January 2007
Guideline: UCPRC- GL- 2005- 01
Pavementt Prreserrvattiion Sttudiies
Techniicall Adviisorry Guiide
Author: D. Jones
Partnered Pavement Research Program ( PPRC) Contract Strategic Plan Element 3.2.9:
Development of Guidelines for Effective Maintenance Treatment Evaluation Test
Sections
PREPARED FOR:
California Department of Transportation
Division of Research and Innovation
Office of Roadway Research
PREPARED BY:
University of California
Pavement Research Center
UC Davis, UC Berkeley
GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide i
DOCUMENT RETRIEVAL PAGE Guideline No: UCPRC- GL- 2005- 01
Title: Pavement Preservation Studies Technical Advisory Guide
Author: D. Jones
Prepared for:
Caltrans
FHWA No:
S/ CA/ RI- 2006/ 25
Date:
January 2007
Strategic Plan No:
3.2.9
Client Reference No:
SPE 3.2.9
Status:
Final
Abstract:
This document provides guidelines for the establishment, monitoring and reporting of pavement
preservation experiments in California. Information is provided in chapters covering:
• Management and responsibilities
• Project fundamentals
• Experiment work plan
• Site selection
• Experiment construction
• Experiment monitoring
• Forensic investigations
• Laboratory testing
• Data analysis, reports and implementation
• Data management and documentation
• Example experiment work plans, checklists and forms
The document aims to assist with achieving successful completion of experiments and implementation of
the findings.
Keywords:
Pavement preservation, experiment evaluation
Proposals for implementation:
Follow protocol in all future pavement preservation and innovative product experiments. Update
as required.
Related documents:
Pavement Preservation Studies Technical Advisory Guide ( UCPRC- GL- 2005- 01)
Signatures:
D. Jones
1st Author
J. Harvey
Technical
Review
D. Spinner
Editor
J. Harvey
Principal
Investigator
M. Samadian
Caltrans Contract
Manager
ii GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide iii
DISCLAIMER
The contents of this report reflect the views of the authors who are responsible for the facts and
accuracy of the data presented herein. The contents do not necessarily reflect the official views
or policies of the State of California or the Federal Highway Administration. This report does not
constitute a standard, specification, or regulation.
DOCUMENT REVIEW AND IMPLEMENTATION STATUS
This document has been reviewed within the University of California Pavement Research
Center, by the Caltrans Division of Research and Innovation, and by the Caltrans Division of
Maintenance, Office of Pavement Preservation and its appointed reviewers.
The document can be used as a guide for the design, construction, and assessment of
pavement preservation experiments. The document is released as a draft for implementation for
a period of 12 months, ending December 2007. Any comments or recommendations to improve
the document, based on use during implementation, should be forwarded to the Chief of the
Office of Pavement Preservation. A revised document, incorporating comments received, will
be released in January 2008.
iv GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide v
PROJECT OBJECTIVES
The objective of this project is to improve the quality of data and analyses obtained from
Pavement Preservation and Innovative Product Experiments in California, and promote
statewide implementation of the findings of successful studies.
This objective will be met after completion of three tasks:
1. Prepare and discuss a draft table of contents for a detailed guideline on undertaking
pavement preservation and innovative product experiments
2. Prepare a detailed guideline
3. Prepare a summarized “ glove- box” version of the detailed guideline
This document addresses Task No 2.
vi GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide vii
TABLE OF CONTENTS
LIST OF TABLES ............................................................................................................................... ....... xii
LIST OF FIGURES........................................................................................................................ ............ xiii
PURPOSE OF THIS GUIDELINE............................................................................................................... xv
1. INTRODUCTION................................................................................................................... .......... 1
1.1. Background..................................................................................................................... .... 1
1.2. Pavement Preservation Definitions...................................................................................... 3
1.3. Key Activities..................................................................................................................... .. 4
1.4. Typical Pavement Preservation Activities............................................................................ 5
1.5. Quality Management............................................................................................................ 6
1.5.1 Caltrans Project Delivery Quality Management Plan .............................................. 7
2. MANAGEMENT AND RESPONSIBILITIES.................................................................................... 9
2.1. Introduction .......................................................................................................................... 9
2.2. Staffing....................................................................................................................... ....... 10
2.2.1 Project Champion.................................................................................................. 11
2.2.2 Project Engineer/ Project Manager ........................................................................ 11
2.2.3 Database Manager ................................................................................................ 12
2.2.4 Instrumentation Technician ................................................................................... 13
2.2.5 Evaluation Team.................................................................................................... 13
3. PROJECT FUNDAMENTALS ....................................................................................................... 15
3.1. Introduction ........................................................................................................................ 15
3.2. Study Proposals................................................................................................................. 16
3.2.1 Pre- proposal .......................................................................................................... 17
3.2.2 Background Study ................................................................................................. 17
3.2.3 Full Proposal.......................................................................................................... 18
3.3. Experimental Design.......................................................................................................... 20
3.3.1 Terminology........................................................................................................... 20
3.3.2 Types of Experiment.............................................................................................. 22
3.3.3 Factorial Experimental Designs............................................................................. 23
3.3.4 Replicate Studies................................................................................................... 25
3.3.5 Evaluation Criteria ................................................................................................. 25
3.3.6 Failure Criteria ....................................................................................................... 26
3.3.7 Experiment Completion ......................................................................................... 26
3.4. Quality Management.......................................................................................................... 26
3.4.1 Documentation Management ................................................................................ 27
3.4.2 Responsibility ........................................................................................................ 27
viii GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
4. EXPERIMENT WORK PLAN......................................................................................................... 29
4.1. Introduction ........................................................................................................................ 29
4.2. Procedure .......................................................................................................................... 30
4.2.1 Project Planning Meeting ...................................................................................... 30
4.2.2 Work Plan Write- up ............................................................................................... 31
4.2.3 Work Plan Review................................................................................................. 32
4.2.4 Approval ................................................................................................................ 32
4.3. Experiment Work Plan Content ......................................................................................... 32
4.4. Experiment Work Plan Format........................................................................................... 34
4.4.1 Table of Contents .................................................................................................. 34
4.4.2 Title and Numbering .............................................................................................. 34
4.4.3 Example................................................................................................................. 35
4.5. Experiment Initiation .......................................................................................................... 35
4.6. Revisions ........................................................................................................................... 35
4.7. Quality Management.......................................................................................................... 35
4.7.1 Documentation Management ................................................................................ 36
4.7.2 Responsibility ........................................................................................................ 36
5. SITE SELECTION...................................................................................................................... ... 37
5.1. Introduction ........................................................................................................................ 37
5.2. Procedure .......................................................................................................................... 38
5.2.1 Desktop Study ....................................................................................................... 39
5.2.2 Site Visit................................................................................................................. 40
5.2.3 Safety Considerations ........................................................................................... 43
5.2.4 Environmental Considerations .............................................................................. 43
5.2.5 Other Considerations............................................................................................. 43
5.2.6 Preliminary Site Report and Approval ................................................................... 44
5.3. Experimental Section Numbering ...................................................................................... 44
5.4. Experimental Section Layout and Marking ........................................................................ 45
5.5. Instrument Installation........................................................................................................ 46
5.6. Weather Station ................................................................................................................. 47
5.7. Checklists..................................................................................................................... ..... 47
5.8. Final Site Report and Approval.......................................................................................... 47
5.9. Quality Management.......................................................................................................... 47
5.9.1 Data Management ................................................................................................. 48
5.9.2 Responsibility ........................................................................................................ 48
6. EXPERIMENT CONSTRUCTION.................................................................................................. 49
6.1. Introduction ........................................................................................................................ 49
6.2. Pre- Construction Assessment ........................................................................................... 50
GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide ix
6.2.1 Reference Standards ............................................................................................ 51
6.3. Construction Assessment .................................................................................................. 52
6.3.1 Proprietary Products.............................................................................................. 52
6.3.2 Observation ........................................................................................................... 53
6.3.3 Measurement......................................................................................................... 54
6.3.4 Reference Standards ............................................................................................ 55
6.4. Material Sampling .............................................................................................................. 55
6.4.1 Reference Standards ............................................................................................ 57
6.5. Instrument Installation........................................................................................................ 57
6.5.1 Reference Standards ............................................................................................ 57
6.6. Checklists..................................................................................................................... ..... 57
6.7. Construction Report and Approval..................................................................................... 57
6.8. Quality Management.......................................................................................................... 58
6.8.1 Data Management ................................................................................................. 58
6.8.2 Responsibility ........................................................................................................ 59
7. EXPERIMENT MONITORING ....................................................................................................... 61
7.1. Introduction ........................................................................................................................ 61
7.2. Background..................................................................................................................... .. 62
7.2.1 Attributes Of Distress............................................................................................. 62
7.2.2 Training and Calibration of Evaluators .................................................................. 67
7.3. Operational Issues ............................................................................................................. 68
7.3.1 Notifications ........................................................................................................... 68
7.3.2 Equipment ............................................................................................................. 68
7.3.3 Road Closures and Traffic Control ........................................................................ 69
7.4. Monitoring Timetable ......................................................................................................... 69
7.5. Protocols and Criteria ........................................................................................................ 70
7.5.1 Failure Criteria ....................................................................................................... 70
7.5.2 Reference Standards ............................................................................................ 71
7.6. Visual Assessment............................................................................................................. 71
7.6.1 Reference Standards ............................................................................................ 73
7.7. Measurements ................................................................................................................... 73
7.7.1 Reference Standards ............................................................................................ 75
7.8. Failure Investigations......................................................................................................... 75
7.9. Sampling ............................................................................................................................ 75
7.9.1 Reference Standards ............................................................................................ 76
7.10. Forensic Studies............................................................................................................. 76
7.11. Checklists ....................................................................................................................... 76
7.12. Quality Management ...................................................................................................... 76
x GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
7.12.1 Quality Control..................................................................................................... 77
7.12.2 Data Management ............................................................................................... 77
7.12.3 Responsibility ...................................................................................................... 78
8. FORENSIC INVESTIGATIONS ..................................................................................................... 79
8.1. Introduction ........................................................................................................................ 79
8.2. Record of Decision............................................................................................................. 81
8.3. Level of Detail .................................................................................................................... 82
8.4. Close- out Monitoring.......................................................................................................... 84
8.5. Level 1 Forensic Assessments .......................................................................................... 84
8.6. Test Pit Location ................................................................................................................ 84
8.7. Coring ............................................................................................................................... 87
8.7.1 Reference Standards ............................................................................................ 87
8.7.2 Equipment ............................................................................................................. 88
8.7.3 Procedure .............................................................................................................. 88
8.7.4 Core Logging ......................................................................................................... 89
8.8. Test Pit Excavation ............................................................................................................ 89
8.8.1 Reference Standards ............................................................................................ 89
8.8.2 Equipment ............................................................................................................. 89
8.8.3 Procedure .............................................................................................................. 90
8.8.4 Excess Materials ................................................................................................... 92
8.9. Marking, Packaging and Shipping ..................................................................................... 92
8.9.1 General Provisions ................................................................................................ 92
8.9.2 Sample Code Number ........................................................................................... 92
8.9.3 Labels and Tags .................................................................................................... 93
8.9.4 Packaging.............................................................................................................. 94
8.9.5 Shipping................................................................................................................. 94
8.10. Core and Test Pit Logging.............................................................................................. 94
8.10.1 Reference Standards .......................................................................................... 95
8.10.2 Logging Procedure .............................................................................................. 95
8.11. In- pit Testing................................................................................................................. 104
8.11.1 Reference Standards ........................................................................................ 104
8.11.2 In situ Density and Moisture Measurements ..................................................... 104
8.11.3 Dynamic Cone Penetrometer ( DCP) Testing .................................................... 106
8.11.4 Other Testing..................................................................................................... 106
8.12. Test Pit Repair .............................................................................................................. 106
8.12.1 Asphalt Concrete Pavements............................................................................ 106
8.12.2 Portland Cement Concrete Pavements............................................................. 107
8.12.3 Site Cleanup ...................................................................................................... 107
GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide xi
8.13. Project Site Report ....................................................................................................... 108
8.14. Checklists ..................................................................................................................... 108
8.15. Quality Management .................................................................................................... 108
8.15.1 Data Management ............................................................................................. 108
8.15.2 Responsibility .................................................................................................... 109
9. LABORATORY TESTING ........................................................................................................... 111
9.1. Introduction ...................................................................................................................... 111
9.2. Tests ............................................................................................................................... 112
10. DATA ANALYSIS, REPORTS AND IMPLEMENTATION.......................................................... 113
10.1. Introduction................................................................................................................... 113
10.2. Data Analysis................................................................................................................ 114
10.3. Reports ......................................................................................................................... 114
10.3.1 Construction Reports......................................................................................... 114
10.3.2 Progress Reports............................................................................................... 115
10.3.3 Experiment ( Research) Reports........................................................................ 115
10.3.4 Implementation Reports .................................................................................... 116
10.4. Implementation ............................................................................................................. 116
11. DATA MANAGEMENT AND DOCUMENTATION...................................................................... 119
11.1. Introduction................................................................................................................... 119
11.2. Project File.................................................................................................................... 119
11.3. Checklists ..................................................................................................................... 120
11.4. Data Collection Forms .................................................................................................. 120
11.5. Numbering Systems ..................................................................................................... 121
11.5.1 Experiment Proposal Register........................................................................... 121
11.5.2 Experiment Register .......................................................................................... 122
11.5.3 Report Number Register ................................................................................... 123
11.6. Data Validation and Storage......................................................................................... 124
11.7. Project Closure ............................................................................................................. 125
12. BIBLIOGRAPHY................................................................................................................... ...... 127
APPENDIX A: PROPOSED CALTRANS INNOVATION PROCESS ..................................................... 130
APPENDIX B: CHECKLISTS .................................................................................................................. 138
APPENDIX C: EXAMPLE EXPERIMENT WORK PLAN........................................................................ 154
APPENDIX D: DATA COLLECTION FORMS......................................................................................... 162
APPENDIX E: EXAMPLE SAMPLE LABEL........................................................................................... 180
xii GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
LIST OF TABLES
Table 1.1: Pavement preservation purpose ................................................................................................. 3
Table 1.2: Typical pavement preservation activities .................................................................................... 6
Table 3.1: Example layout of factorial experimental design....................................................................... 25
Table 7.1: General description of degree classification ............................................................................. 64
Table 7.2: General description of extent classifications ............................................................................. 65
Table 7.3: Examples of physical measurements........................................................................................ 73
Table 8.1: Forensic investigations associated with pavement preservation activities ............................... 80
Table 8.2: Checklist for test pit logging ( wearing course) ........................................................................ 100
Table 8.3: Severity and extent descriptors for wearing course layer assessment ................................... 101
Table 8.4: Checklist for test pit logging ( bound layers) ............................................................................ 102
Table 8.5: Severity and extent descriptors for bound layer assessment ................................................. 102
Table 8.6: Checklist for test pit logging ( unbound layers) ........................................................................ 103
Table 8.7: Severity and extent descriptors for unbound layer assessment ............................................. 103
GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide xiii
LIST OF FIGURES
Figure 1.1: Components of pavement preservation ..................................................................................... 1
Figure 1.2: Flowchart of key activities .......................................................................................................... 5
Figure 2.1: Typical staff organization chart for pavement preservation experiments ................................ 11
Figure 3.1: Flowchart for project approval.................................................................................................. 16
Figure 3.2: Flowchart for background study............................................................................................... 19
Figure 3.3: Flowchart for factorial experimental design ............................................................................. 24
Figure 4.1: Flowchart for development of an experiment work plan .......................................................... 30
Figure 5.1: Flowchart for site selection....................................................................................................... 38
Figure 5.2: Example layout of experimental section ( one lane width)........................................................ 45
Figure 6.1: Flowchart for experiment construction ..................................................................................... 50
Figure 7.1: Flowchart for experiment monitoring........................................................................................ 62
Figure 7.2: Flow diagram – five point classification system....................................................................... 65
Figure 7.3: Diagrammatical illustration of extent ........................................................................................ 66
Figure 8.1: Flowchart for forensic investigations........................................................................................ 81
Figure 8.2: Flowchart for determining level of detail of the forensic investigation...................................... 83
Figure 8.3: Test pit layout ........................................................................................................................... 86
Figure 8.4: Examples of core locations on asphalt concrete sections ....................................................... 86
Figure 8.5: Examples of core locations on portland cement concrete sections ......................................... 87
Figure 8.6: Plan view of test pit face to be logged ..................................................................................... 96
Figure 8.7: Zoning of the test pit face......................................................................................................... 96
xiv GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
Guideline purpose xv
PURPOSE OF THIS GUIDELINE
This guideline has been written to assist Caltrans staff with establishing and monitoring pavement
preservation experiments. Experience has shown that, although numerous such experiments have been
built in the past, very little useful information that can be used to make informed decisions about
implementing the treatment, technology, procedure or product state- wide results. There are a number of
reasons for this including movement and turnover of staff, inappropriate experimental designs, insufficient
data collection and/ or loss of interest over time ( i. e., experiment is never completed). Considerable time
and expense are incurred during the establishment of experiments. Failure to complete an experiment
invariably means that it will be repeated by someone else, somewhere else at a later date. The same
applies to experiments that although completed, are not coordinated at state level.
This guideline provides direction on the following:
• Establishing a study team and assigning responsibilities
• Justification for doing an experiment
• Developing an experiment work plan
• Locating, marking out and establishing the site
• Construction of the experiment
• Monitoring the experiment
• Data analysis
• Reporting and implementation
• Data management
By applying the principles discussed in the guideline, the following can be achieved:
• Statistically valid, scientifically correct and defendable answers obtained within a determined time
period
• Results from every experiment established, regardless of the movement of individuals within and
out of the organization
• Findings that are applicable state- wide and useable by individuals outside the study
• Justification for expenses incurred
• Justification for statewide implementation
• Justification for changes to specifications and practices
• Accountability of individuals involved
• Prevention of duplication of effort
xvi GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
1. Introduction 1
1. INTRODUCTION
1.1. Background
Pavement preservation represents a proactive approach in maintaining highways.
It enables State Departments of Transportation ( DoTs) to reduce costly, time
consuming rehabilitation and reconstruction projects, and the associated traffic
disruptions. With timely preservation the traveling public can be provided with
improved safety and mobility, reduced congestion, and smoother, longer lasting
pavements.
A Pavement Preservation program consists primarily of three components
( Figure 1.1):
• Preventive maintenance
• Minor rehabilitation ( non structural)
• Routine maintenance activities
Figure 1.1: Components of pavement preservation
Caltrans invests millions of dollars each year in pavement preservation activities.
Documented performance of the pavement preservation practices during these
activities is important so that Caltrans can determine which alternatives are most
appropriate under particular circumstances. Many factors contribute to this decision
including:
• Nature of the problem requiring maintenance
• Existing pavement geometry
• Construction materials
• Location ( District)
• Traffic
• Safety
MTAG
Crack seal
Shoulder fog seal
Diamond grinding
Pavement
preservation
Minor
rehabilitation
Preventive
maintenance
Routine
maintenance
2 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
• Environment
• Cost
• Current practice and available equipment
To establish the most appropriate pavement preservation practice or to assess
the performance and effectiveness of new materials or equipment, experiments
are usually constructed and then monitored over a period of time. Provided that
an appropriate experimental design is followed, the experiment is monitored
regularly and objectively and the data is suitably interpreted, these experiments
can contribute significantly to the understanding of pavement preservation and
the state- wide implementation/ adoption of the most appropriate and cost-effective
practices.
However, in many instances, the purpose of the experiment is not clearly defined,
accepted monitoring standards are not adhered to, data are not effectively
captured, and the experiment is not completed with a result on which a decision
can be made with regard to state- wide implementation. Alternatively, the
originator of the experiment moves and his/ her successor may not be aware or
may not be willing to sustain the exercise. Consequently, inconclusive results are
often obtained and the new procedure or practice is not adopted. Invariably, the
experiment is repeated elsewhere by another individual, often with the same
inconclusive result.
The purpose of this document is to provide Caltrans personnel with guidelines for
the consistent design, construction and monitoring of experimental sections,
capturing and storing data and interpreting and documenting the results. This
guideline supplements the “ Maintenance Technical Advisory Guide ( MTAG)” and
the “ Guide to the Investigation and Remediation of Distress in Flexible
Pavements” and uses information from those documents as well as past test
section project evaluations located throughout the State of California.
The document is presented in two parts:
• A comprehensive document providing detailed information on establishing
and monitoring pavement preservation test sections ( this document).
• A summary guide in the form of brief descriptions and checklists on key
components of establishing and monitoring pavement preservation test
sections.
The purpose of this document is to
provide Caltrans personnel with
guidelines for the consistent
design, construction, and
monitoring of experimental
sections, capturing and storing
data, and interpreting and
documenting the results.
1. Introduction 3
1.2. Pavement Preservation Definitions
The distinctive characteristics of pavement preservation activities compared to construction, rehabilitation and
emergency maintenance are that they restore the function of the existing roadway system and extend its service
life, but do not increase capacity or strength ( Table 1.1).
Table 1.1: Pavement preservation purpose
Purpose
Category Activity
Increase
capacity
Increase
strength
Reduce aging Restore
serviceability
Construction New construction
Reconstruction








Rehabilitation Major rehabilitation
Structural overlay






Pavement
Preservation
Minor rehabilitation
Preventive maintenance
Routine maintenance





Maintenance Reactive maintenance
Catastrophic maintenance


Different pavement preservation terminology is often used by local and State
DoTs. This can cause inconsistency relating to how preservation programs are
applied and their effectiveness measured. To overcome these inconsistencies, the
Federal Highway Administration ( FHWA) has proposed a number of definitions
( FHWA Memorandum on Pavement Preservation Definitions, 09/ 12/ 05).
• Pavement Preservation is “ a program employing a network level, long- term
strategy that enhances pavement performance by using an integrated, cost-effective
set of practices that extend pavement life, improve safety and meet
motorist expectations.” ( FHWA Pavement Preservation Expert Task Group )
• Preventive Maintenance is “ a planned strategy of cost- effective treatments
to an existing roadway system and its appurtenances that preserves the
system, retards future deterioration, and maintains or improves the
functional condition of the system ( without significantly increasing the
structural capacity).” ( AASHTO Standing Committee on Highways, 1997)
• Minor rehabilitation consists of non- structural enhancements made to the
existing pavement sections to eliminate age- related, top- down surface
cracking that develop in flexible pavements due to environmental exposure.
Because of the non- structural nature of minor rehabilitation techniques,
these types of rehabilitation techniques are placed in the category of
pavement preservation.
Pavement preservation - chip
seal
Preventive maintenance - dowel
bar retrofit
4 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
• Routine Maintenance “ consists of work that is planned and performed on a
routine basis to maintain and preserve the condition of the highway system
or to respond to specific conditions and events that restore the highway
system to an adequate level of service.” Source: AASHTO Highway
Subcommittee on Maintenance
Definitions of the other activities listed in Table 1.1 are:
• Pavement Reconstruction is required when a pavement has either failed or
has become functionally obsolete. It entails the replacement of the entire
existing pavement structure with an equivalent or increased pavement
structure.
• Major Rehabilitation consists of “ structural enhancements that extend the
service life of an existing pavement and/ or improve its load carrying capacity.
Rehabilitation techniques include restoration treatments and structural
overlays.” Source: AASHTO Highway Subcommittee on Maintenance
• Corrective Maintenance activities are performed in response to the
development of a deficiency or deficiencies that negatively impact the safe,
efficient operations of the facility and future integrity of the pavement section.
Corrective maintenance activities are generally reactive, not proactive, and
performed to restore a pavement to an acceptable level of service due to
unforeseen conditions.
• Catastrophic Maintenance describes work activities generally necessary to
return a roadway facility back to a minimum level of service while a
permanent restoration is being designed and scheduled. Examples of
situations requiring catastrophic pavement maintenance activities include
concrete pavement blow- ups, road washouts, avalanches, or rockslides.
1.3. Key Activities
The design, construction, monitoring and reporting of experimental sections can be
divided into a number of key activities, all of which are equally important in ensuring
that relevant data are captured and interpreted in such away that an informed
decision can be taken on the implementation of the findings of an experiment.
These activities include:
• Delegating responsibility
• Preparing an experimental design
Routine maintenance - crack
repair
Pavement reconstruction
Major rehabilitation
Corrective maintenance
Catastrophic maintenance
1. Introduction 5
• Selecting and establishing a suitable site
• Construction
• Monitoring
• Forensic studies
• Laboratory testing
• Data management
• Reporting and implementation
A flow chart of the process is provided in Figure 1.2. Each activity is discussed in
more detail in the following chapters.
Figure 1.2: Flowchart of key activities
1.4. Typical Pavement Preservation Activities
Various pavement preservation activities are performed on highways. Certain
activities are preventive in that they are performed before any significant distress
Fog seal
Establish team
Identify need for
experiment
Prepare experiment workplan
Laboratory testing
Prepare proposal
Select and establish site
Construct experiment
Forensic Monitor experiment investigation
Analyze data
Prepare reports
Prepare implementation plan
Implement
6 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
has occurred. Others are remedial and are carried out to repair distresses in the
pavement. Many routine activities are unlikely to be assessed in research
experiments and will not be covered in any detail in this document. Typical
activities that may well be researched are listed in Table 1.2. The list is not
exhaustive and only provides an example of activities commonly investigated in
pavement preservation experiments. The list does include issues such as
drainage, pavement markings, barriers, water crossings and vegetation control,
although investigations can be undertaken on these with a view to improving
techniques or assessing new products.
Table 1.2: Typical pavement preservation activities
Activity* Area treated Preventive Remedial
Thin overlays
Ultra- thin overlays
Bonded wearing course
Microsurfacings
Chip seals
Slurry seals
Fog seals
Total













-
Crack seal
Crack fill
Joint seal
Patching
Partial- depth concrete repair
Full- depth concrete repair
Edge repair
Diamond grinding
Dowel bar retrofit
Selective
-
-
-
-
-
-
-
-









-
* Activities may include the use of mechanical improvements such as
geotextiles or geogrids
Throughout this document, where appropriate, activities will be referred to as ‘ total’
and ‘ selective’ treatments as detailed in the table.
1.5. Quality Management
Quality management is the coordination of activities to direct and control an
organization with regard to quality. A quality management system is used to guide
this process and, in the case of pavement preservation test sections, refers to
Caltrans’ structure for managing its processes and activities that transform inputs
of resources into a product or service which meet the organization’s objectives,
namely ensuring consistently designed and tested experiments that provide good
quality data that can be used with confidence to develop and implement
procedures to improve delivery of infrastructure in California.
Slurry seal
Microsurfacing
Thin overlay
Quality management is the
coordination of activities to direct
and control an organization with
regard to quality.
1. Introduction 7
Where there is employee turnover, the quality management system and its
associated documentation is an aid to continuity of operations. It assists in
managing operations based on procedures and not people and helps to prevent
unacceptable changes in practice that may occur as a result of changes in
personnel.
Quality management encompasses a number of key components.
1.5.1 Caltrans Project Delivery Quality Management Plan
The Caltrans Project Delivery Quality Management Plan ( QM) was established to
implement and document a fully integrated project delivery " Quality System" that
would be applied to all transportation projects regardless of funding source,
sponsorship, or who performs the work. This plan focuses on the delivery of
Quality Transportation Projects, emphasizing accountability and utilizing
continuous improvements, to assist the Department in achieving its mission to
" Improve mobility across California”.
Quality Management ( QM)
Quality management consists of discrete activities that establish the quality
objectives, policy, and responsibilities; and implements these responsibilities with
the aid of Program Reviews ( PR), Independent Assurance ( IA), Quality Assurance
( QA), Quality Control ( QC), and continuous improvement within each of these
activities.
Program Review ( PR)
Program review includes those activities that establish the objectives and
requirements for quality, based on program level evaluations of trends and
performance measures. Program Review should cause validation, modification, or
redirection of business practices related to project delivery.
Independent Assurance ( IA)
Independent assurance are those activities performed at the corporate level
( Division Chiefs and District Directors) to help assure that quality management
practices are in place, functioning, and effective. Independent Assurance should
cause continuous improvement in policies and procedures related to project
delivery.



8 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
Quality Control ( QC)
Quality Control refers to the operational processes, practices and activities
performed by the project team during the project delivery process. It is used to
verify that deliverables are of acceptable quality and that they meet the
completeness and correctness criteria established in the quality planning process.
Quality Control is conducted continually throughout a project and is the
responsibility of team members and the project manager.
Quality Assurance ( QA)
Quality Assurance does not refer directly to the specific deliverables themselves
but rather to the process used to create the deliverables. In general, quality
assurance activities focus on the processes used to manage and deliver the
solution, and can be performed by a manager, client or a third- party reviewer. For
instance, an independent project reviewer might not be able to tell if the content of
a specific deliverable is acceptable. However, they should be able to tell if the
deliverable seems acceptable based on the process used to create it. They can
determine, for instance, whether reviews were performed, whether it was tested
adequately, whether the client approved the work, etc.
Quality assurance includes activities performed at the district management
( functional management) level, during the project delivery process. They provide
the confidence that the project team is fulfilling established project requirements
and expectations.
QC
Example
1 st level data checks by
another team member after
monitoring
QA
Example
Establishment of an
evaluator training and
calibration procedure to
ensure consistency in
evaluations
2. Management and Responsibilities 9
2. MANAGEMENT AND RESPONSIBILITIES
2.1. Introduction
A team of suitably qualified and experienced personnel is required to manage, establish and evaluate
pavement preservation experiments in close liaison with
other units who have responsibility for the road. This
team will be accountable for optimizing the establishment
and evaluation of pavement preservation experiments
and presentation of the highest quality data possible in a
format that is useable by other Divisions within Caltrans.
The establishment and evaluation of experiments is
expensive. Outcomes may result in state- wide changes
to current practice and specifications and implementation
might be scrutinized by many individuals within the state,
Establish team
Identify need for
experiment
Prepare experiment workplan
Laboratory testing
Prepare proposal
Select and establish site
Construct experiment
Forensic Monitor experiment investigation
Analyze data
Prepare reports
Prepare implementation plan
Implement
10 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
as well as nationally and internationally. Roles and responsibilities thus need to be clearly defined and
monitored by means of appropriate job descriptions, key- result areas and performance evaluation.
2.2. Staffing
The success of each pavement preservation experiment
is directly dependent on the individuals that develop the
experiment plan, establish the section, do the
evaluations, undertake laboratory tests, and collect, store
and analyze the data. The roles and responsibilities of
each position in the team thus need to be clearly defined
to ensure that relevant positions in the team are
accountable for the actions required to effectively deliver
each part of the project. It is important to ensure that
positions, and job descriptions for those positions, are
not created around individuals, but rather to achieve optimal functionality. This will ensure continuity and
sustainability of an experiment when staff changes occur - an important issue given the long- term nature
of many experiments.
Depending on a particular project, one person may undertake more than one role, but must then accept
responsibility for each. Positions will usually form part of a larger job description ( e. g., the District
Materials Engineer may also be the Project Engineer for a pavement preservation experiment).
In the event of staff changes, the project champion will need to ensure that the new staff member
assumes the responsibilities of the job description, including those linked to pavement preservation
experiments. The job description should be sufficiently comprehensive to ensure that the new incumbent
is aware of his/ her responsibilities and can accomplish them once adequate training has been carried out.
Typical staffing requirements associated with pavement preservation experiments include the following:
• Project Champion
• Project Engineer/ Project Manager
• Database Manager
• Instrumentation Technician
• Evaluation Team
Certain functions could be carried out by the same person, and the positions are unlikely to be full- time
The recommended staffing structure is illustrated in Figure 2.1.
2. Management and Responsibilities 11
Figure 2.1: Typical staff organization chart for pavement preservation experiments
The job descriptions for those positions that are involved with the experiment should be modified to
include the additional duties, in line with Caltrans requirements, each with clearly defined roles and
responsibilities. Each modification/ appointment should be accepted in writing by the appointee and filed
with his/ her employment documentation. Thereafter the individual should be held accountable for those
responsibilities and performance should be rated on achievements related to them.
2.2.1 Project Champion
The Project Champion is typically the Maintenance Engineer. Although this individual may not have
initiated the research ( i. e., the Project Proposer), he/ she will have overall responsibility for the experiment.
These responsibilities include:
• Liaison with other interested and affected divisions and offices within Caltrans
• Overall program management and accountability
• Securing sustainable funding to complete the study
• Strategy development and review
• Project identification in line with the strategy
• Delegation of authority to the Project Engineer
• Project Experiment Work Plan approval
• Quality management of outputs
• Industry liaison, coordination feedback and implementation
The Project Champion may also establish a panel consisting of the proposer, experts in the treatments of
processes being assessed, and industry, for some of these duties.
2.2.2 Project Engineer/ Project Manager
The Project Engineer is often, but not necessarily, the initiator or proposer of the experiment. He/ she is
responsible for overall project management, compiling the Experiment Work Plan and then ensuring that it
is correctly implemented. If a new product is being assessed, the project Engineer shall follow the
guidelines for new product evaluation. He/ she will coordinate and lead evaluations and laboratory testing
Project Champion
Project Engineer Database Manager
Instrument Technician Evaluation team
12 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
ensuring that appropriate evaluations and testing are being carried out to meet the objectives of the
Experiment Work Plan. He/ she will discuss the need for changes to the Experiment Work Plan and will be
responsible for preparing the first- level report for the test. Involvement in second level analysis and
reporting may also be required and will depend on the investigation. This individual reports to the Project
Champion and his/ her job description and key result areas should accommodate the following
responsibilities for which he/ she should be held accountable and evaluated against:
• Liaison with the Project Champion on all aspects pertaining to the experiment( s)
• Liaison with product/ technology providers if applicable.
• Maintain a Project File in which all documentation relevant to the experiment is stored
• Preparation of Experiment Work Plans, project experiment designs and project specifications
• Management of and delegation of authority to the Instrumentation Technician and Evaluation Team
• Site location
• Layout of the experiment
• Test and control section construction
• Supervision of instrument installation and calibration
• Coordination of associated laboratory testing and control sample storage
• Training and calibration of evaluators
• Evaluations
• Liaison with the Database Manager to ensure that data is useable, in the correct format, and
distributed to the required individuals
• Data validation, first level analysis of results and reporting
2.2.3 Database Manager
The Database Manager should report to the Project Champion and should have the following
responsibilities for which he/ she should be held accountable:
• Provide input to the project Experiment Work Plan in terms of data formats, database requirements
and naming and numbering conventions
• Establish a database architecture to suit the Experiment Work Plan for each project
• Remind the Project Engineer of scheduled monitoring visits
• Liaise with the Project Engineer and Laboratory Manager to ensure timely and accurate capture of
data into the database
• Quality checks on all data
• Maintain the database including links to Experiment Work Plans and reports, backups and updating
of all files and all backups to the latest software versions
• Ensure that all data files are appropriately stored and that raw data is never altered
• Ensure that a backup is made of the Project Engineers relevant hard drive files on completion of
each project and stored together with other files from the project
2. Management and Responsibilities 13
• Facilitate report printing and distribution in suitable formats
• Ensure long- term availability and accessibility of all records in the database
• Establish and maintain an archive of all reports and documents prepared on pavement preservation
experiments within the office of the Chief of Pavement Preservation
2.2.4 Instrumentation Technician
If test sections are instrumented, an Instrumentation Technician may need to be appointed. This
individual will report to the Project Engineer and his/ her job description and key result areas should
accommodate the following responsibilities for which he/ she should be held accountable:
• Instrument installation and calibration
• Training of assistants
• Ensuring that a sufficient inventory of instrument components and consumables is maintained and
that orders for replacement are placed in a timely way.
2.2.5 Evaluation Team
The Evaluation Team is led by the Project Engineer and should have the following responsibilities:
• Evaluation of the experiment( s) according to the requirements of the Experiment Work Plan
• Submission of data to the database manager
• Assistance to the Project Engineer with first level analysis
14 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
3. Project Fundamentals 15
3. PROJECT FUNDAMENTALS
3.1. Introduction
The project fundamentals revolve around the need to do the experiment and the implications of
implementing the findings. Pavement preservation
experiments are built for a variety of reasons,
primarily to understand the behavior, performance
and potential benefits of doing something new or
differently. However, experience has shown that in
many instances, the objectives for constructing an
experiment are often not fully thought out, insufficient
background study is carried out, inappropriate data is
collected, monitoring programs and protocols are not
adhered to, the results are not written up, and the findings are not implemented. Therefore, it is
imperative that the reason for initiating the experiment is fully understood and that a comprehensive
Establish team
Identify need for
experiment
Prepare experiment workplan
Laboratory testing
Prepare proposal
Select and establish site
Construct experiment
Forensic Monitor experiment investigation
Analyze data
Prepare reports
Prepare implementation plan
Implement
16 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
experimental design is prepared in order to ensure that the objectives are met and, if successful, the
procedure being evaluated can be adopted as standard practice, where appropriate, with confidence.
Someone also needs to take and maintain overall responsibility throughout the life of the experiment,
which includes handing it over to another individual if that person moves within the organization, or leaves.
In this chapter, study proposals, background studies and experimental designs are introduced. A flow
chart depicting the processes covered in this chapter is provided in Figure 3.1.
Figure 3.1: Flowchart for project approval
3.2. Study Proposals
Study proposals are considered in two phases by Caltrans - pre- proposal and full proposal. A summary of
a process proposed by Caltrans Division of Maintenance, Office of Pavement Preservation, is provided in
Appendix A, with full details on meeting the requirements provided in the following chapters. The pre-
Problem identification
Accept?
Yes
Yes
No
No
Preliminary study proposal
Continue?
Background study
Record of decision
Experiment Work Plan
Experimental design
Record of decision
Terminate study
Prelim experimental design
Yes
No
Accept?
Detailed study proposal
3. Project Fundamentals 17
proposal, discussed below, is essentially submitted as a justification to undertake the study. The full
proposal provides more detail and is submitted after additional work has been carried out.
3.2.1 Pre- Proposal
The pre- proposal should be prepared as the first step in the process and should include the following:
• Project title
• Project Proposer and Project Champion and their contact information
• A purpose definition in the form of a problem statement or hypothesis, for example:
o “ Evaluate the performance of proprietary grids for preventing reflective cracking in thin
overlays” or “ Pothole filler ‘ A’ is better than Pothole filler ‘ B’”
• Details on the proposed process or innovation including:
o Description
o Patent information if applicable
o Conditions under which it has been designed to perform. Distress conditions should be
consistent with descriptions in the Maintenance Technical Advisory Guide ( MTAG) and/ or
Caltrans Pavement Condition Survey Manual.
o Selection criteria used to determine where the process or innovation can be used
o Specifications including design and construction/ application
o Information on where it has been used, including field performance data
• Reasons and justification for undertaking the study
• Potential benefits of the study, both monetary and operational
Pre- proposals should be approved by the Pavement Preservation Task Group Chair and, if a new product
is being considered, the New Products Coordinator. Once approved, a background study should be
undertaken to gather sufficient information on which to base a decision on proceeding with or halting a
study.
3.2.2 Background Study
Before embarking on a detailed research study and construction of
experiments that could be both expensive and time consuming, the
proponent should carry out a background study to see if similar studies
have been carried out elsewhere in the state, in the country or
internationally. The study can be done through Caltrans libraries and
on the Internet ( e. g., Google search and Google Scholar search). A
detailed literature review, interviews and even some pilot laboratory
testing may be required before a decision is made to continue with the study. A brief state- of- the- art
report should be prepared on completion of this phase summarizing:
• Overview of why the study is being undertaken and the potential benefits to Caltrans
18 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
• Findings of the literature review, including:
o Details on any similar research that has been carried out
o The reasons why the practitioners undertook the study
o Status of the study
o How the findings were implemented and what the implications were
• Results from the preliminary laboratory study if undertaken
• Applicability of the findings to California
• Justification to continue or discontinue the study
• Proposed experimental design
The justification to continue with a study would typically be based on the following ( see Figure 3.2 and
Checklist 1 in Appendix B):
• No similar work had been carried out elsewhere
• The findings were not applicable to California ( e. g., different materials or climate)
• The research was not carried out in a scientific manner such that statistically valid results were
obtained
• The experiment could be considered as a replicate of the previous experiment with data being used
to enhance the analysis and reliability of the findings
• The experiment could be considered as another cell in the experimental design covering a specific
aspect ( e. g., environmental or traffic) not covered in the previous experiment
3.2.3 Full Proposal
A full proposal should be prepared after completion of the background study. This proposal should
include the content from the pre- proposal and background information documents, as well as:
• Potential partners ( those who have a vested interest in the results and who could make technical,
financial or “ in- kind” contributions)
• Project logistics, including:
o Potential locations for the experiment
o Estimated project costs
o Potential problems, impacts and remedies
o Warranties
o Safety and environment, including any material safety data sheets ( MSDS), safety forms
received from the product suppliers and any additional safety and environmental issues that
need to be addressed
• Proposed work plan ( see Chapter 4) and timetable
• Estimated study budget
• Definition of success, including the performance and cost criteria that will define success compared
to current Caltrans practice.
3. Project Fundamentals 19
• Details on how the findings would be implemented including expected deliverables, who would lead
the implementation process and probable timetable and cost
• Signed commitment by the project team to complete the study
Figure 3.2: Flowchart for background study
Background study
Has research been
done?
Are findings applicable
to Caltrans?
Are findings
statistically valid?
Will repeating the
study advance
knowledge?
Will additional
experiment accelerate
implementation?
Prepare experimental
design
Abandon experiment Record of decision Record of decision
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
20 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
A decision to proceed with the experiment should be made by the Project Champion after review of the
background study report and full proposal. A record of decision should be documented. A checklist for
preparing/ reviewing proposals is provided in Appendix B ( Checklist 2). Once approved, details on the
experiment should be added to a central register of experiment proposals, maintained by the Chief of the
Office of Pavement Preservation. The experiment register is discussed in Chapter 11. A project file
should be opened by the Project Engineer and a copy of the approved proposal filed together with any
other relevant documentation. Copies of the Project File should be kept by the Project Champion,
Database Manager and any other individuals involved in the study who will need access to relevant
information.
3.3. Experimental Design
The experimental design is a fundamental component of the
Experiment Work Plan, which is discussed in the following chapter.
Sufficient time and effort should always be given to organizing the
experiment properly to ensure that the right type of data, and enough
of it, is available to answer the questions of interest as clearly and
efficiently as possible. This process is called experimental design.
The specific questions that the experiment is intended to answer must be clearly identified together with
known or expected sources of variability in the experimental units. One of the main aims of a designed
experiment is to reduce the effect of these sources of variability on the answers to questions of interest.
That is, the experiment should be designed in order to improve the accuracy and precision of the answers.
The experimental design is a basic plan of how the study/ experiment will be carried out in order to draw a
valid conclusion. It should consider all relevant dependent and independent variables and should be
sufficiently comprehensive such that a statistically valid conclusion is arrived at. Where appropriate, the
experimental design should not be restricted to single experiments and instances, and replicates and
variables should be considered to ensure that the results are applicable throughout the state or that the
limitations of the procedure, technology or product are fully understood such that it is not implemented
where it will not perform satisfactorily.
3.3.1 Terminology
The following terminology is commonly used in the preparation of experimental designs:
• Treatments - In experiments, a treatment is something that researchers ‘ administer’ ( e. g., the
comparison of different chip seals to assess which has the least stone loss after opening to traffic).
Treatments are usually divided into ' levels', where level is either a categorical variable ( e. g., Binder
A, B and C) and/ or an amount or magnitude ( e. g., different binder spray rates or temperatures).
3. Project Fundamentals 21
• Factor - A factor of an experiment is a controlled independent variable; a variable whose levels are
set by the experimenter. A factor is a general type or category of treatments. Different treatments
constitute different levels of a factor ( e. g., three different binder types are applied at different
temperatures. The binders are the experimental units and the application temperatures are the
treatments, where three different temperatures constitute three levels of the factor ' type of binder').
Typical factors that may be considered in an experimental design include, but are not limited to:
o Traffic and type of vehicle
o Environment ( weather, subgrade conditions, water table, etc.)
o Materials
o Type of pavement
o Geometry and slope
o Construction factors ( e. g., binder temperature, compaction equipment)
o Laboratory test methods that can be correlated with field performance
• Factorial Design - A factorial design is used to evaluate two or more factors simultaneously. The
treatments are combinations of levels of the factors ( e. g., three binder types, applied at two different
temperatures, in three different climatic zones at two different traffic levels [ total of 36 sections]).
The advantage of factorial designs over one- factor- at- a- time experiments is that they are more
efficient and they allow interactions to be detected. Factorial designs are commonly used in road
experiments.
• One Way Analysis of Variance - is the comparison of several groups of observations, all of which
are independent but possibly with a different mean for each group. A test of great importance is
whether or not all the means are equal. The observations all arise from one of several different
groups ( or have been exposed to one of several different treatments in an experiment). ‘ One- way’ is
classified according to the group or treatment.
• Two Way Analysis of Variance - is a way of studying the effects of two factors separately ( their
main effects) and ( sometimes) together ( their interaction effect).
• Completely Randomized Design - the structure of the experiment in a completely randomized
design is assumed to be such that the treatments are allocated to the experimental units completely
at random.
• Randomized Complete Block Design - is a design in which the subjects are matched according to
a variable which the experimenter wishes to control. The subjects are put into groups ( blocks) of
the same size as the number of treatments. The members of each block are then randomly
assigned to different treatment groups. ( e. g., A researcher is carrying out a study of the
effectiveness of four different crack sealants. He/ she has 100 cracks on which to assess the
sealants and plans to divide them into four treatment groups of 25 cracks each. Using a randomized
block design, the cracks are assessed and put into blocks of four according to width; the four widest
cracks are the first block, the next four widest are the second block, and so on to the 25th block.
22 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
The four cracks of each block are then randomly assigned, one to each of the four treatment
groups).
• Main Effect and Interaction Effect - the main effect is the simple effect of a factor on a dependent
variable. It is the effect of the factor alone averaged across the levels of other factors. ( e. g., the
results of experiments indicate that two different fog seals and one chip seal were all effective in
extending the life of a pavement surfacing ( main effect of fog seal and main effect of chip seal).
When fog seals and chips seals are considered in combination; the two fog seals might have
worked equally well ( main effect of fog seal); fog seal A and a later chip seal showed the benefits of
both ( main effect of fog seal A and main effect of chip seal). However, it might have been found
that the use of fog seal B, followed by a later chip seal showed the benefits of both plus a ‘ bonus’,
such as significantly extended life of the chip seal, known as an interaction effect ( main effect of fog
seal B, main effect of chip seal plus an interaction effect).
• Interaction - is the variation among the differences between means for different levels of one factor
over different levels of the other factor.
• Randomization - is the process by which experimental units ( the basic objects upon which the
study or experiment is carried out) are allocated to treatments; that is, by a random process and not
by any subjective and hence possibly biased approach. The treatments should be allocated to units
in such a way that each treatment is equally likely to be applied to each unit. Randomization is
preferred since alternatives may lead to biased results. It tends to produce groups for study that
are comparable in unknown as well as known factors likely to influence the outcome, apart from the
actual treatment under study. The analysis of variance F tests assume that treatments have been
applied randomly.
• Control - is a ‘ do nothing’ or a standard treatment to which the performance is compared ( e. g., an
experiment to assess the ability of grids to reduce cracking must include a control where no grid is
used, built to exactly the same specifications, but excluding the grid).
• Replicate - is a repetition of an experiment to quantify the influence of factors such as variability in
materials, construction procedures, climate, traffic, etc. Replicates can be constructed at the same
site ( e. g., to assess variability in materials) and/ or at different sites ( e. g., to assess influence of
climate or traffic). Replicates improve the statistical validity of the experiment, but are often
overlooked in the experimental design.
3.3.2 Types of Experiment
Pavement preservation experiments can take many forms, including but not limited to one or a
combination of the following:
• Assessing a new strategy/ treatment/ technology ( i. e., does this technology “ work”?)
• Comparing one strategy/ treatment/ technology with another ( i. e., which is the “ best” treatment?)
• Refining a strategy/ treatment/ technology ( i. e., what is the “ best way” to do this treatment?)
• Understanding a treatment/ technology ( i. e., “ how” does this technology work?)
3. Project Fundamentals 23
They will typically involve both laboratory and field
experiments. Testing may be phased, beginning with
laboratory tests that will screen a comprehensive
experimental design, followed by accelerated pavement
testing ( Heavy Vehicle Simulator ( HVS)), if appropriate, on
a refined ( reduced) experimental design, and then
completed with full- scale field ( pilot) experiments where
an even more refined experimental design is assessed.
The first two phases will provide confidence for the
engineers to test under actual traffic and environmental
conditions. Laboratory testing is relatively inexpensive and is used as a screen. Accelerated pavement
testing is considerably more expensive than laboratory testing, but still much cheaper than field studies. It
should be noted that accelerated pavement testing with the HVS is only appropriate for assessing the
effects of load and cannot be used for assessing the effects of speed, wheel turning and dynamic loading,
or environmental factors such as aging, diurnal temperature changes and wet and dry seasons.
For example, in an assessment of thin maintenance overlays using modified binders, the performance of
all possible binder and aggregate combinations can be tested in a laboratory using fatigue beam and
shear tests. The best performing combinations can then be subjected to accelerated pavement testing,
which will provide an indication of which combinations can be tested in full- scale pilot studies with
confidence.
3.3.3 Factorial Experimental Designs
As mentioned above, factorial experimental designs are often used in pavement preservation
experiments. Care must be taken in deciding on the factors that will be assessed in order to keep the
experiment focused and manageable. It should be remembered that the addition of a factor will result in
an exponential increase in the number of cells in the factorial design. For example, assume an
experiment to compare two modified binders with a conventional binder in a chip seal application is
proposed. This will require three test sections for a basic experiment without a replicate. If performance
is considered to be influenced by traffic, and three different traffic levels are considered, the factorial
increases to 3x3 cells or nine sections ( typically at three different locations). If application temperature is
also raised as an issue and two different temperatures are considered, the factorial increases to 3x3x2 or
18 sections, and so on. Partial factorial experiments are often used where not all cells are assessed, but
instead a selection is tested to identify trends. Unrealistic combinations can also be eliminated to reduce
the number of sections.
A flow chart depicting the factorial experimental design decision process is shown in Figure 3.3.
24 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
Figure 3.3: Flowchart for factorial experimental design
Key purpose of experiment ( a x n)
Can other treatments
be considered for
comparison ( b)?
Will performance be
influenced by climate
( c)?
Will performance be
influenced by traffic
( d)?
Will performance be
influenced by
subgrade ( e)?
No Yes
Identify other treatments ( bn)
Identify climatic regions ( cn)
E. g.,
Central coast
Inland valley
High desert/ high mountain
Low mountain/ north coast
South coast
South mountain
Identify traffic classes ( dn)
E. g.,
Traffic index < 7
Traffic index 7- 10
Traffic index 11- 14
Traffic index > 14
Identify subgrade classes ( en)
E. g.,
R value < 10
R value 15 - 25
R value > 30
Will performance be
influenced by other
factors ( f)?
Identify other factors ( fn) E. g.,
Construction variables
Pavement type
Calculate number of experiments
( a x b x c x d x e x f)
No Yes
No Yes
No Yes
No Yes
( b = 0)
( c = 0)
( d = 0)
( e = 0)
( f = 0)
3. Project Fundamentals 25
An example layout of a factorial experimental design for an assessment of chip seals is shown in
Table 3.1. The control would typically be standard practice and Seals 1- 3 would, for example, be:
• A tighter grading ( e. g., < 5 percent material larger or smaller than nominal aggregate size) with
standard binder
• A rubber modified binder with standard grading
• A tighter grading with rubber modified binder
Table 3.1: Example layout of factorial experimental design
Climate Traffic Pavement Surface treatment
condition Control Seal 1 Seal 2 Seal 3
Good
Low
Poor
Good
Coastal
High
Poor
Good
Low
Poor
Good
Valley
High
Poor
Good
Low
Poor
Good
Mountain
High
Poor
3.3.4 Replicate Studies
Replicate studies are important in many types of experiment, especially where variables ( construction,
material variability, weather) can influence performance of the treatment being assessed. The inclusion of
replicates will improve the reliability of the findings. Two types of replicate need to be considered:
• Replications within the same test section, typically used to deal with construction, material, and/ or
pavement variability within the test section.
• Replications between other regions, materials, pavement types, climates and/ or traffic, etc. in the
state to identify boundaries to implementation, if these are not already being considered as factors
in the experimental design.
Replications are often overlooked as they are considered to be too expensive. However, experience has
shown that if sufficient replicates are not built and assessed, satisfactory implementation is rarely
achieved as engineers are resistant to apply new technologies that were not proven under their specific
conditions. Replicates can be considered as part of the factorial experimental design as depicted in
Figure 3.3.
3.3.5 Evaluation Criteria
Key evaluation criteria, on which the success of the treatment will be decided, need to be established for
each experiment. These should be linked to the experiment objective. For example, if two modified
26 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
binders are being compared in a chip seal experiment, the key evaluation criteria will probably be
raveling/ stone loss over time. Evaluation criteria are discussed in more detail in Chapter 7.
3.3.6 Failure Criteria
In any experiment, it is important to establish and
understand what the failure criteria for any
experiment are and what action needs to be taken
when failure occurs. Examples of failure criteria
include rut depth, stone loss and length or area of
cracking.
It should be remembered that most learning with
regard to pavement performance and behavior will
be derived from understanding the failure mechanism. It is thus preferable to design experiments in such
a way that failure will occur on certain sections. Researchers should be encouraged to adopt this line of
thinking and to avoid only designing experiments that do not ‘ fail’. Care will need to be taken when
selecting experiment locations to ensure that road users are not endangered and that maintenance or
rehabilitation of the section can be rapidly undertaken without major disruption to traffic.
3.3.7 Experiment Completion
The criteria for deciding when an experiment is completed should also be determined in the experimental
design. This will be the point at which sufficient data has been collected such that an informed decision
can be made on whether to adopt/ proceed with implementation or reject the strategy/
treatment/ technology. It could be time ( e. g., level of performance after a period of elapsed time) or
performance based ( e. g., no improvement over control in terms of performance indicators).
3.4. Quality Management
Quality management issues pertaining to the roles and responsibilities described in this
chapter include:
• Preparation of study proposals
• Completion of a background study to determine whether the research has already
been undertaken and/ or is relevant to California
• Consideration of an experimental design that will provide sufficient data such that statistically valid
conclusions can be drawn with respect to the objectives of the study
• Approval of the preliminary project proposal, background study and detailed proposal by the Project
Champion

3. Project Fundamentals 27
• Approval by the Pavement Preservation Task Group Chair in line with the Caltrans Innovation
Process
• Documentation of all records of decision
• Opening a central Project File containing all documentation relevant to the study
3.4.1 Documentation Management
At the beginning of any experiment, a Project File should be opened by the Project Proposer. All
documentation associated with the study should be kept in this file. Copies of relevant documents should
be sent to the project team. Once a proposal has been approved and a project team assembled, the
Project Engineer ( often also the Project Proposer) should assume responsibility for the Project File in
his/ her capacity as Project Manager.
A register of all project proposals should be centrally maintained, together with a record of decision on
whether to proceed or not. This will limit unnecessary duplication of research.
3.4.2 Responsibility
The Project Engineer is responsible for:
• Preparing and submitting the project proposals
• Undertaking or delegating someone to undertake the background study
• Writing the background study report
• Opening and maintaining a Project File
• Distributing copies of relevant documents to the project team
The Project Champion is responsible for:
• Guiding the proposals through the Innovation Process
• If a phased approach is followed, approving the background study
• Deciding on whether to proceed with the full study in collaboration with the Pavement Preservation
Task Group Chair
• Completing a record of decision
• Updating the central experiment register in the Office of Pavement Preservation ( see Chapter 11).
28 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
4. Experiment Work Plan 29
4. EXPERIMENT WORK PLAN
4.1. Introduction
The Experiment Work Plan is a comprehensive document detailing the objectives of the experiment, the
experimental design, the control, evaluation procedures, and responsible persons. It should be
considered a “ live” document in that changes during the course of the
experiment are often necessitated. An Experiment Work Plan must be
prepared for every experiment once the decision to proceed with an
experiment is made by the Project Champion and Pavement
Preservation Task Group Chair after completion and review of the
background study and detailed proposals ( see Appendix A).
In this chapter, the procedure for preparing an experiment work plan,
the work plan content and format and revisions to the work plan are discussed. A flow chart of the
process covered in this chapter is provided in Figure 4.1.
Establish team
Identify need for
experiment
Prepare experiment workplan
Laboratory testing
Prepare proposal
Select and establish site
Construct experiment
Forensic Monitor experiment investigation
Analyze data
Prepare reports
Prepare implementation plan
Implement
30 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
Figure 4.1: Flowchart for development of an experiment work plan
4.2. Procedure
The preparation of an Experiment Work plan involves four main stages:
• Project planning meeting
• Work plan write up
• Work plan review
• Work plan approval
4.2.1 Project Planning Meeting
The project planning meeting is held to agree on the test objective and to formulate a framework for the
test such that appropriate data will be collected.
The following individuals should participate:
• Project Champion
• Project Engineer
• Database Manager
• District Engineer( s) and maintenance staff from the districts in which the experiments are planned
• Other interested parties, for example, suppliers of products that are being evaluated, and
contractors who will be undertaking the work
Add experimental spec number
Discussion workshop following
set agenda
Incorporate changes
Schedule experiment
Approve
Write draft experimental spec
Yes
Accept?
Distribute to working group
Experiment work plan
No
4. Experiment Work Plan 31
The agenda for the project planning meeting should
include:
• Objective of the experiment
• Implications of the findings from the background
study
• Experimental design to meet the test objective
• Control experiment for comparative purposes
• Experiment location
• Construction requirements
• Instrumentation and equipment required to provide data for envisaged outcome
• Monitoring program
• Monitoring procedure
• Failure and experiment completion criteria
• Associated laboratory experiments
• Data collection, validation and storage
o Frequency of data collection
o Data validation ( visual, comparison with previous measurement, within predefined parameters)
o Data transfer to Database Manager ( timing, medium)
• Reports
• Criteria to be met for strategy/ treatment/ technology/ procedure/ product to be adopted as standard
practice
• Implementation plan if successful
• Repairs to road after testing
• Other
The Project Engineer should facilitate the project planning meeting and minute the discussion. These
minutes will be used to prepare the Experiment Work Plan.
The above agenda framework should be used as a checklist to ensure that all relevant issues are
discussed and that a satisfactory outcome has been recorded for each. A copy of the agenda in checklist
form is provided in Appendix B ( Checklist 3).
4.2.2 Work Plan Write- Up
The Project Engineer should write the Experiment Work Plan based on the agreements reached at the
project planning meeting. Although each Experiment Work Plan will differ according to the objective, a
generic content and table of contents should be adhered to, to ensure that all relevant issues are
documented. Guidelines for content and table of contents are provided in the following sections.
32 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
Responsibilities for preparing the Experiment Work Plan include those of the:
• Project Champion - responsible for ensuring that the test objectives are aligned with Caltrans
policy and procedures
• Project Engineer - responsible for preparing the Experiment Work Plan and liaising with the team
members
• Database Manager - responsible for providing information on data collected from past experiments
with which the proposed experiment may be compared, naming and numbering conventions,
formats, data transfer, database design and population and data and report archiving
4.2.3 Work Plan Review
The draft Experiment Work Plan should be reviewed by the project planning meeting attendees. The
review should focus on technical content and correctness only. Fundamental changes to what was
agreed upon at the meeting should not be made. The Project Engineer should coordinate the review
process and is responsible for setting deadlines for comments, receiving comments, discussing changes
with the team members and revising the document.
4.2.4 Approval
The final Experiment Work Plan should be approved with the following signatures:
• Project Champion
• Project Engineer
• Database Manager
• District Engineer( s)
4.3. Experiment Work Plan Content
The following information should be included in the Experiment Work Plan. Details on each component
are discussed in more detail in later chapters.
• Objective of the test
• Staffing and contact details
• Responsibility and reporting matrix
o Report preparation
o Report approval
o Health and safety
o Environmental considerations
o Data collection
o Data validation
o Data submission
o Data storage
4. Experiment Work Plan 33
• Experimental design, including details on replicates and controls
• Section detail
o Section number
o Section details including district, county, route number, lane number and GPS coordinates
o Test panel position
o Pavement description
o Construction, rehabilitation or maintenance required before testing can begin
o Checklists
• Instrumentation
o Inventory of instruments
o Location and/ or depth
o Calibration
o Measurement specifications
o Data collection requirements ( number and location of
points and conditions under which measurements will be
recorded)
o Checklists
• Evaluation program
o Evaluation requirements
o Protocols/ methods/ criteria to be followed
o Failure criteria definition
o Associated laboratory testing
o Checklists
• Data collection, validation and storage
o Start date
o Frequency of data collection
o Data validation ( visual, comparison with previous measurement, within predefined parameters)
o Data transfer to Database Manager ( timing, medium)
o Criteria to be met for experiment completion
o Checklists
• Reports
• General notes
Checklists should be prepared for each phase of the experiment. These should be used to guide the
process and ensure that all parts are completed. They should be signed off by the responsible individuals
on completion of a task.
34 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
It should be noted that experimental designs should always have an end point. It is thus imperative to
include criteria that once met, will result in the termination of the experiment monitoring, data analysis and
lead to a recommendation adopting the strategy, treatment, technology, procedure and/ or product.
The above list can be used as a checklist to monitor content of the document. An example of such a
checklist is provided in Appendix B ( Checklist 4).
4.4. Experiment Work Plan Format
4.4.1 Table of Contents
The Experiment Work Plan should be formatted as follows ( see Checklist 5 in Appendix B):
• Title Page
• Approval signatures
• Revision Notes
• Table of contents
o Chapter 1: Objective of the test
o Chapter 2: Staffing and contact details
o Chapter 3: Responsibility and reporting matrix
o Chapter 4: Experimental design
o Chapter 4: Section detail
o Chapter 5: Instrumentation
o Chapter 6: Monitoring program
o Chapter 7: Data collection, validation and storage
o Chapter 8: Reports
o Chapter 9: General notes
o Appendices: Checklists and forms
4.4.2 Title and Numbering
The title of the Experiment Work Plan should be a brief descriptor of the project.
Each Experiment Work Plan prepared should have a unique number to facilitate tracking of updates and
changes and for archiving and retrieval purposes. The numbering system for Caltrans Pavement
Preservation Experiments documents is maintained by the Chief of the Office of Pavement Preservation
and is kept centrally ( instead of District level) to track experiments statewide. It is linked to the proposal
register described in the previous chapter. The document numbering system is discussed in Chapter 11.
4. Experiment Work Plan 35
4.4.3 Example
An example of an Experiment Work Plan for a pavement preservation experiment is provided in
Appendix C.
4.5. Experiment Initiation
The experiment can be initiated as soon as:
• The Project Champion has given final written approval for the work plan
• An experiment number has been issued by the Chief of the Office of Pavement Preservation
• The project team has accepted responsibility for the tasks assigned to them in the work plan
A copy of the approval should be kept in the Project File. A checklist for experiment initiation is provided
in Appendix B ( Checklist 6).
4.6. Revisions
The Experiment Work Plan is a live document and might change during the course of an experiment as
monitoring progresses. Changes must only be made in order to meet the original objectives of the study
and must be agreed to by all individuals involved in preparing the original Work Plan. Examples of
changes may include different monitoring intervals, the use of different equipment to measure specific
parameters, additional tests, maintenance interventions, etc. Extensions of the experiment may also be
justified.
Any changes to the Experiment Work Plan must be documented in a revision and a new version issued.
The new version must be re- approved before implementation. The changes and section numbers in
which the changes have been made should be listed on the first page of the revised document.
The Project Engineer is responsible for changes, obtaining approvals, circulation of the revised document
and ensuring that the changes are implemented.
4.7. Quality Management
Quality management issues pertaining to the roles and responsibilities described in this
chapter include:
• The preparation of a responsibility matrix
• The preparation of a comprehensive Experiment Work Plan that defines and
allocates all responsibilities required to meet the objectives of the experiment
• Approval of the Experiment Work Plan by all contributors

36 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
• Documenting all changes to the Experiment Work Plan in revised documents that are re- approved
and issued with a revision number and date
• Setting criteria for experiment termination and subsequent decision making on whether or not to
adopt the strategy, treatment, technology, procedure and/ or product as standard Caltrans practice.
4.7.1 Documentation Management
The Experiment Work Plan should be stored in the Project File. New versions of the Work Plan should be
circulated to all relevant parties by the Project Engineer.
4.7.2 Responsibility
The Project Engineer is responsible for:
• Project Management
• Compiling and revising the Experiment Work Plan. It is imperative that this responsibility remains
with the Project Engineer, unless he/ she delegates it to someone else, in order to prevent
uncoordinated and unapproved changes to the Experiment Work Plan that may adversely influence
meeting the original objectives.
• Ensuring that new versions of the Experiment Work Plan are approved, distributed and added to the
Project File
The Project Champion retains overall responsibility for approving and implementing the Work Plan.
5. Site Selection 37
5. SITE SELECTION
5.1. Introduction
Site selection is critical. The site needs to be representative of roads, traffic and environment where the
pavement preservation strategy might be used if proved
successful in the proposed experiment. If feasible,
experiments can be combined to optimize monitoring
schedules and comparisons between ongoing
performances of the different studies. All experiments
should include a control section and replicates. Control
sections are typically the standard pavement
preservation strategy that would have been used. For
example, if a new chip seal design is being assessed,
the experiment should include a section constructed using the existing chip seal design so that a direct
comparison of performance can be made. Replicates are typically included to assess variability at each
Establish team
Identify need for
experiment
Prepare experiment workplan
Laboratory testing
Prepare proposal
Select and establish site
Construct experiment
Forensic Monitor experiment investigation
Analyze data
Prepare reports
Prepare implementation plan
Implement
38 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
site and the influence of, for example, climate and traffic between sites. Replicates for assessing the
effect of traffic and/ or structure can often be accommodated by using side- by- side experiments on
different lanes/ directions if traffic differences between the lanes/ directions are sufficiently large.
In this chapter, site selection procedure, experiment numbering, layout and marking, and instrument
installation are discussed. A flow chart depicting the processes covered in this chapter is provided in
Figure 5.1.
Figure 5.1: Flowchart for site selection
5.2. Procedure
The identification and selection of experiment sections will depend on the specific criteria and objectives of
the study. The following general issues should, however, be considered when selecting sections:
• Sections should be representative of the issue being investigated and results obtained from these
sections should be representative of other roads with similar conditions.
• Where possible experiments should be conveniently located for monitoring and or demonstration
purposes.
Site visit
Layout and mark
Assign experiment number
Desktop study
Yes
Meet
requirements?
Site selection
No
Select uniform sections
Schedule construction
Install instruments
5. Site Selection 39
• Individual sections within the experiment, including the control, should be similar in terms of
alignment, structure, traffic carried, and condition. Side- by- side sections should not be used for
direct comparison, but can be used for replicates to assess differences in traffic and/ or structure.
• The establishment of the section should not pose a safety hazard to road users, or be positioned so
that the safety of the persons monitoring the section is jeopardized.
• The road on which the section is being located should not be maintained, rehabilitated or resealed
within the planned monitoring period, unless assessment of that intervention is part of the
monitoring program and prior warning is given to the Project Engineer.
• Sections should be located as close as possible to traffic counting/ weigh- in- motion stations, unless
a station is incorporated into the section.
• Sections should be selected such that testing to “ failure” of certain sections can be completed and
then repaired without significant impacts to the road user.
 Road is curved, sight distance is
limited, and structure is inconsistent  Road is straight, safe and
consistent
The procedure involves three main stages:
• Desktop study
• Site visit
• Approval
5.2.1 Desktop Study
The desktop study, undertaken by the Project Engineer in consultation with the District Engineer( s), is
done to identify and evaluate all available alternatives that meet the requirements of the Experiment Work
Plan in general and the experimental design in particular, bearing in mind that pavement preservation
experiments are typically incorporated into planned pavement preservation activities. A shortlist of
potential sites, including replicates if applicable, will be prepared as an output. A checklist, based on the
40 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
requirements of the Experiment Work Plan, should be completed to ensure that no issues are overlooked.
An example of a desktop study checklist is included in Appendix B ( Checklist 7). Examples of issues to
consider include, but are not limited to:
• Can the planned strategies/ treatments be accommodated in the operation?
• Can the planned pavement preservation strategy/ treatment on the selected section be used as a
control?
• Is the planned operation long enough to accommodate the
experiments, each of which must be long enough to ensure that
the contractor can construct a representative section?
• Is the alignment uniform?
• Is the planned operation long enough to accommodate
replicate sections?
• Are there any potential problems with later monitoring activities
( e. g., road closures)?
• Are there constraints outside the Experiment Work Plan that
could influence the use of the site ( e. g., safety or environmental
issues)?
• Is appropriate construction equipment available?
• Are there appropriately trained personnel to do the treatments?
• Can the contractual arrangements be modified to
accommodate the experiment?
The selected sites should be ranked according to appropriateness. If replicate sections are required,
these should be identified in the ranking. Ranking can be simplified by giving a score ( on a scale of 1 to 3
where 1 is satisfactory, 2 is acceptable with exceptions and 3 is unsatisfactory) to each of the above
questions.
5.2.2 Site Visit
Following the desktop study, the Project and District Engineers and, if applicable, the supplier( s) of any
products that might be evaluated, should visit the selected locations and identify the most appropriate
site( s). Non- destructive ( e. g., profile, falling weight deflectometer) and/ or destructive [ e. g., test pit, coring,
Dynamic Cone Penetrometer ( DCP)] testing, together with a visual assessment, may be required to
characterize the site. Criteria used to select sites could include, but not be limited to:
• Total and selective surface treatments
o Riding quality [ e. g., International Roughness Index ( IRI)]
o Cracking ( e. g., length of crack in mm/ km plus crack width or percentage area cracked)
o Rut depth ( e. g., mm)
o Bleeding/ punching [ e. g., severity ( 1- 5) and extent ( percentage area)]
5. Site Selection 41
• Total surface treatments
o Age ( e. g., years or period since last treatment)
o Skid resistance [ e. g., Skid Number ( SN)]
o Pavement structure ( e. g., deflection in micron, DCP number, back calculated modulus)
• Selective treatments
o Potholes
Site selection based on pavement structure ( FWD) Site selection based on skid resistance ( Dynamic
friction tester)
Uniformity of these criteria, and specifically the pavement structure, within the selected site is critical to the
success of the experiment so that comparisons of performance between sections and other analyses are
accurate. The identification of uniform sections within the selected site is thus an important task.
Uniformity is relative to the length of the experiment. For short sections [ e. g., < 200 m ( 600 ft)] there
should be minimal variation in the key parameter being assessed. For longer sections ( e. g., 1.0 km or
1.0 mile), some variability is inevitable, but at least the middle 300 m ( 1,000 ft) should be uniform and the
key parameter should not differ by more than 10 percent on the remainder of the section.
Issues to consider when selecting uniform sections include, but are not limited to:
• Total and selective surface treatments
o Riding quality - the entire length of the available road should be measured and uniform
sections of the required length selected from the data. A variation of not more than
10 percent is permissible. Sections can be distributed along the length of the available road
and need not all be next to each other. If there is a distinctive change over the length of the
section, then replicates can be considered, one in a smoother area and one in a rougher area.
o Cracking - the characteristics of the cracking, in terms of the evaluation criteria used, should
be consistent along the length of the section.
42 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
o Rut depth - the rut depth should not vary by more than ± 3.0 mm ( 0.1 in.) along the length of
the section
o Bleeding/ punching - the severity and extent of the bleeding and/ or punching should be the
same throughout the length of the experiment. Replicates can be considered if the severity
and/ or extent change by more than one rating point along the length of the selected site.
Consistent cracking on selected section Consistent bleeding/ stone loss on selected section
Inconsistent rutting and cracking Inconsistent spalling, cracking, and faulting
• Total surface treatments
o Age - the entire length of the section should be the same age and should have been
constructed at the same time as part of the same contract.
o Skid resistance - the entire length of the available road should be measured and uniform
sections of the required length selected from the data. A variation of not more than
10 percent is permissible. Sections can be distributed along the length of the available road
and need not all be next to each other. If there is a distinctive change over the length of the
section, then replicates can be considered, one in the smoother area and one in the rougher
area.
5. Site Selection 43
o Pavement structure - sufficient deflection and/ or DCP measurements should be taken to
ensure that at least five readings are used to identify any one section. Thus a measurement
should be taken at least every 20 m. A variation of not more than 10 percent is permissible.
Sections can be distributed along the length of the available road and need not all be next to
each other. If there is a distinctive change over the length of the section, then replicates
should be considered.
5.2.3 Safety Considerations
Pavement preservation experiment sections should only be located where they will have minimum impact
on road user safety and on the safety of individuals and equipment during monitoring exercises.
Experiments should thus only be located where there is good visibility and sufficient space to
accommodate traffic.
5.2.4 Environmental Considerations
Test sections should not be constructed in sensitive environments where construction activities may have
significant impacts or where runoff or leachate from treatments could influence surrounding ecosystems.
Environmental conditions should also not influence the sections in any significant way unless they are
included as factors in the experimental design. For example, the experimental sections should have
adequate drainage.
Example of a safe experimental section Example of an environmentally sensitive road -
experiments should be avoided in these areas.
5.2.5 Other Considerations
There are a number of other issues that should be considered when selecting a site or sites for an
experiment. These include, but are not limited to ( see Checklist 8 in Appendix B):
• Where possible, the proposed sections should be conveniently located for monitoring and
demonstration purposes
44 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
• Planned maintenance or rehabilitation on the road during the period of experimentation should be
established and the consequences determined. If planned maintenance is not part of the
evaluation, steps will need to be taken to ensure that none takes place.
• Where possible, sections should be located as close as possible to traffic counting, weigh- in- motion
and/ or weigh stations to ensure that accurate traffic records are used in the analyses.
• In many instances, it is desirable to test the road to the predefined failure criteria. The implications
of testing to failure, including required repairs and disruptions to traffic need to be determined
before committing to a site.
5.2.6 Preliminary Site Report and Approval
Once a site, or sites if a factorial experimental design is being followed or replicates are being considered,
has been selected, a brief site report should be prepared by the Project Engineer detailing the following:
• Site selection process
• Criteria used to select individual sections
• Exact locations of each section ( mileage from a fixed point and GPS coordinates)
• Measured parameters for each section
• Safety and environmental considerations
The Experiment Work Plan should also be updated to incorporate the exact section locations and
numbering and a new version issued.
Approval of the location( s) should be signed off by the following individuals:
• Project Champion
• Project Engineer
• Database Manager
5.3. Experimental Section Numbering
Each experiment, and section within the experiment if
applicable, should be assigned a unique number for
management purposes. A number should be obtained
from the Chief of the Office of Pavement Preservation.
This number will be linked to the proposal and experiment specification registers described in the previous
chapter. Examples of the register format and numbering system are provided in Chapter 11.
Obtaining the experiment and section numbers should be the responsibility of the Project Engineer. The
numbers used should correspond to those used in the Experiment Work Plan and on all subsequent
reports.
PPTS/ 3/ 05/ 1/ 1
5. Site Selection 45
5.4. Experimental Section Layout and Marking
Labeling and marking of the test sections and control should be the responsibility of the Project Engineer.
Once selected the test sections should be labeled, marked and instrumented according to the
requirements of the Experiment Work Plan. Suitable signs should be erected at either end of the
experiment with experiment details and a contact number or website where Caltrans staff can obtain
additional information and notify the Project Engineer of any observations or interventions that may be
necessary.
The length of the experiment will be detailed in the Experiment Work Plan and will vary depending on the
treatment being assessed. Typical sections lengths are:
• Total surface - 200 m ( 600 ft)
• Selective surface - sufficient length to have at least 12 replicates with the same treatment ( i. e.,
12 cracks, 12 potholes, 12 joints)
Long test sections are more representative of the road and allow the collection of larger quantities of data.
However, they are time consuming to evaluate and variability along the length of the section will need to
be accounted for. The length of the test section thus needs to be optimized such that the experiment
objectives can be satisfactorily met.
• Experimental sections that assess total surface treatments can be divided into two parts - a larger
experiment over which riding quality is measured ( e. g., 500 m) and a shorter section ( e. g., 200 m)
in the middle where the visual assessment and more precise measurements are taken. The same
applies to experiments where construction is a factor. The larger experiment will typically cover a
full- day production ( e. g., 1.5 km or 1.0 mi) with one or more representative 200 m ( 600 ft) sections
within the larger experiment. Each detail section can be further divided into panels to facilitate
evaluation. The control section dimensions should be identical to those of the experiment. An
example of a layout typically used for experiments assessing total surface is provided below
( Figure 5.2):
A 1 2 3 4 5 B 6 7 8 9 10 C
< 20m> 5 x 15m 10m 5 x 15m < 20m>
200 m
Not to scale
Figure 5.2: Example layout of experimental section ( one lane width)
46 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
• 2 x20 m ( 65 ft) panels ( A and C) at either end for destructive testing ( DCP, density and moisture
content, core)
• 1 x10 m ( 32 ft) panel ( B) in the middle for destructive testing ( DCP, density and moisture content,
core)
• 10 x15 m ( 50 ft) panels ( 1 - 5 and 6 - 10) for general performance assessment
The GPS coordinates of the start of Panel A, center of Panel B, and end of Panel C of each section and
the chainage ( distance from the post- mile marker) at the beginning and end of each section should be
taken and recorded in the database to facilitate location.
Each section should be marked as follows:
• Signboards with the section number should be erected at either end of each section against the
fence line/ edge of the road reserve. If additional sections are incorporated for riding quality
measurements, additional signs should be erected at the start and end point as well.
• Each section should be demarcated and numbered with white road marking paint ( Figure 5.2).
Locator points for specific measurements [ e. g., deflection ( FWD)] should also be painted.
A “ map” of each section should be drawn after completion of the demarcation and filed in the Project File
at a central point to facilitate future assessments. An example of an experiment map is provided in
Appendix C.
5.5. Instrument Installation
In certain instances, experimental sections may be instrumented in order to collect specific data.
Instrumentation requirements will be detailed in the Experiment Work Plan. Typical instrumentation could
include, but is not limited to:
• Temperature or temperature/ humidity buttons
• Thermocouples
• Strain and or deflection gages
• Crack activity measuring instruments
• Traffic counters and or weigh- in- motion sensors
Instrumentation should be installed and calibrated as prescribed by
the manufacturer/ supplier, if necessary by trained, experienced and competent technicians.
The control section must be instrumented exactly the same as the experimental sections.
The Project Engineer must oversee the calibration and installation of the instrumentation.
Crack activity measurement
5. Site Selection 47
5.6. Weather Station
Weather data will be an important component of the analysis. If
there is no suitable weather station in the vicinity of the
experiment, a station comprising at least a thermometer
( maximum and minimum) and a rain gage should be erected as
close as possible to the section.
5.7. Checklists
Checklists for site location, layout and marking and instrumentation should be completed and signed off by
the Project Engineer and approved by the Project Champion. Examples of checklists for the chapter are
provided in Appendix B.
5.8. Final Site Report and Approval
Once the site has been marked, signed, and instrumented, a final site report should be prepared by the
Project Engineer and approved. This report will incorporate the preliminary site report detailed earlier,
together with the following:
• Experiment number
• Experiment map
• Details of instrumentation location, installation, and calibration
Approval of the site report should be signed off by the following individuals. Report approval signifies that
construction can commence.
• Project Champion
• Project Engineer
• Database Manager
5.9. Quality Management
Quality management issues pertaining to the roles and responsibilities described in this
chapter include:
• Identification of a suitable location for the experiment
• Issuing each section a unique number
• Layout of the sections according to the Experiment Work Plan
• The drawing of a “ map” of the section with all relevant information including instrumentation
• The completion and signing of checklists for each stage

48 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
5.9.1 Data Management
Data collected during this phase of the experiment will typically include a “ map” of the experiment ( treated
sections and control), a list of the instrumentation with locations and details of calibration, and details of
the weather station. Section numbers will need to be recorded in a central experiment register. All
documentation generated during this phase of the experiment should be added to the Project File.
5.9.2 Responsibility
The Project Engineer has overall responsibility for:
• Locating the experiment
• Laying out and marking the sections
• Obtaining experiment and section numbers
• Preparing a “ map” of the experiment
• Overseeing the calibration and installation of the instrumentation
• Revising the Experiment Work Plan
• Completing all checklists
• Recording the details of the experiment in the experiment register
• Maintaining the Project File
The Database Manager is responsible for:
• Entering the experiment details in the database
The District Engineer is responsible for:
• Approving the location of the site
The Project Champion has overall responsibility for:
• Ensuring that the site meets the objectives of the experiment
• Ensuring that all Caltrans requirements in terms of safety and environment are met
• Approving all checklists
6. Experiment Construction 49
6. EXPERIMENT CONSTRUCTION
6.1. Introduction
The performance of any road is directly related to the quality
of construction. It is therefore imperative that the construction
process is closely observed so later performance can be
related back to it. Since pavement preservation strategies are
being evaluated, it is also very important that the road is
comprehensively evaluated before any work is undertaken in
order to determine the level of success of the strategy.
When undertaking any assessments, observations or
measurements, it should always be kept in mind that the data
Establish team
Identify need for
experiment
Prepare experiment workplan
Laboratory testing
Prepare proposal
Select and establish site
Construct experiment
Forensic Monitor experiment investigation
Analyze data
Prepare reports
Prepare implementation plan
Implement
50 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
will ultimately be used in an analysis to determine the effectiveness of the technique and/ or product being
assessed. Careful consideration should thus be given to the manner in which the assessments are
recorded such that quality analysis can be undertaken and valid conclusions drawn.
In this chapter, pre- construction assessment, construction assessment, material sampling and instrument
installation are discussed. A flow chart for the chapter is shown in Figure 6.1.
Figure 6.1: Flowchart for experiment construction
6.2. Pre- Construction Assessment
The experiment should be systematically and comprehensively assessed prior to construction. The
assessment criteria used should be as detailed in the Experiment Work Plan and should remain consistent
throughout the study. The California Pavement Condition Survey Manual and/ or the FHWA Distress
Identification Manual for the Long- term Pavement Performance Program should be used together with any
additional requirements detailed in the work plan. Profile, riding quality and deflection, if specified in the
Experiment Work Plan, should all be measured according to documented procedures.
Typical issues to consider in the pre- construction assessment include, but are not limited to ( see
Checklist 10 in Appendix B):
Construction assessment
Report
Instrument installation
Pre- construction assessment
Experiment construction
Material sampling
Schedule monitoring
Yes
Construction
satisfactory?
No
Reject experiment
6. Experiment Construction 51
• Relevant distresses listed in the Visual Assessment Guide/ Distress Identification Manual including,
but not limited to:
o Cracking ( fatigue, block, edge, longitudinal, reflection, transverse, corner, durability)
o Potholes and/ or existing patching and patch deterioration
o Surface Deformation ( rutting, shoving)
o Surface Defects ( bleeding, polished aggregate, raveling, map cracking, scaling, popouts)
o Miscellaneous Distresses ( lane- to- shoulder drop- off, lane- to- shoulder separation, water
bleeding and pumping, blowouts)
o Joint Deficiencies ( joint seal damage, spalling, faulting)
o Longitudinal profile/ riding quality
• Skid resistance
• Drainage on the road
• Drainage away from the road
• Structure ( FWD, DCP)
Structural assessment. Note salt in cracks. Poor drainage may influence experiment
performance.
All observations should be recorded on a Pre- assessment Visual Assessment Form. The form in the
Pavement Condition Survey Manual can be used. Alternatively, a customized form that suits the
experiment, based on the form used in the Pavement Condition Survey Manual, can be used ( Example
Forms 1 and 2 in Appendix D). Any additional notes relevant to the experiment should also be noted on
the form.
6.2.1 Reference Standards
• Caltrans Pavement Condition Survey Manual
• Distress Identification Manual for the Long- Term Pavement Performance Program
52 GL- 2005- 01: Pavement Preservation Studies Technical Advisory Guide
6.3. Construction Assessment
Every aspect of the construction process, from preparation of the surface through cleaning up excess
materials ( e. g., brooming after chip seal application) can influence later performance of the treatment.
The entire process thus needs to be observed and systematically documented so later performance can
be linked to the construction process where applicable. Such observation may also form the basis of a
motivation to change construction practices or training programs within Caltrans to address any specific
problem areas.
Examples of critical areas requiring observation include, but are not limited to:
• Calibration of the spray and stone application rate on fog seals and chip seals