RUBBERIZED ASPHALT CONCRETE
WARRANTY PILOT PROJECTS
VOLUME 1 - CONSTRUCTION REPORT
State of California Department of Transportation
Materials Engineering and Testing Services
Office of Flexible Pavement Materials
5900 Folsom Blvd
Sacramento, California 95819
November 15, 2005
RAC Warranty Pilot Projects Volume 1 - Construction Report November 15, 2005
Caltrans/ CIWMB Partnered Research
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EXECUTIVE SUMMARY
Between 2002 and 2004 Caltrans built five pilot projects through its rehabilitation program that contain
specifications for rubberized asphalt concrete ( RAC) overlay and include a 5- year warranty on the RAC
materials and workmanship. The overall objective of these RAC warranty pilot projects was to provide a
“ level playing field” for “ wet process” ( rubber- modified asphalt binders produced in the field or at a
terminal) and “ dry process” ( CRM as an aggregate substitute) rubber- modified mixes that contain a
minimum of 15% CRM ( by total mass of binder).
This report is Volume 1 of a three volume series. Volume 2 is the interim performance report, which
accompanies this report and includes performance monitoring results to date. Volume 3 will be a final
report which will be prepared by Caltrans at the completion of the 5- year performance monitoring period.
This report presents a compendium of the available information related to site conditions, design,
materials, and construction for the five individual RAC warranty projects. It is intended to provide
information to supplement annual performance monitoring data and to help identify factors related to
materials and/ or construction that may affect the performance of the respective RAC pavements. Each of
the 5 projects is presented in an individual chapter that addresses: traffic and environmental data;
preconstruction activities including deflection testing, structural design, pavement condition survey;
selection of performance evaluation sections ( PESs) for warranty enforcement; surface preparation;
construction activities ( e. g., plant, materials, paving equipment, QC/ QA data); post- construction testing
and/ or monitoring. Information and guidelines developed for the Resident Engineers ( RE) overseeing
RAC warranty projects are included in the Appendices which also contain detailed project- specific
information, such as: pre- construction pavement condition survey data, photos, and deflection data;
construction photos; and materials and testing data.
Performance of the respective projects and PESs is to be evaluated over time. Annual monitoring will
provide the performance information required for warranty enforcement. However a full evaluation of
RAC performance requires consideration of materials characteristics ( including but not limited to
gradation, binder content, mixture voids, stability), construction factors including compaction, structural
adequacy of the pavement section including subgrade and base courses, and site conditions including
drainage.
The warranty approach created some confusion regarding needs and responsibilities for sampling and
testing. The warranty specifications did not include requirements for frequency of sampling and testing
and thus available resources ( which were typically limited), rather than the guidelines supplied to the
REs, governed how much testing was performed. There were considerable differences in the amount of
sampling and testing performed for the respective pilot RAC warranty projects by Caltrans, Contractors,
and their respective agents. As a result, there are gaps in the available data. For some projects, the
information needed for in- depth performance analysis is not available. If pavement distress does occur,
additional sampling and testing may be required to identify the likely causes.
Recommendations include continuation of condition monitoring throughout the life of the subject RAC
overlays. Limited District resources may require extending the interval between condition surveys of
PESs to several years, but long term performance documentation would be useful even if limited. In
addition, if Caltrans performs similar studies of any paving material in the future where sampling and
testing are critical to the overall evaluation, it is recommended that the requirements for sampling and
testing be included in the project special provisions to assure that they are followed.
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TABLE OF CONTENTS
1.0 INTRODUCTION ......................................................................................... 1
1.1 BACKGROUND AND OBJECTIVES............................................................................ 1
1.2 ORGANIZATION OF THE REPORT ........................................................................... 2
2.0 VENTURA COUNTY, HIGHWAY 150 ..................................................... 3
2.1 PROJECT LOCATION............................................................................................... 3
2.2 DESIGN CONSIDERATIONS...................................................................................... 3
2.3 PRE- CONSTRUCTION.............................................................................................. 5
2.3.1 Deflection Testing and PES Selection .................................................................... 6
2.3.2 Pavement Condition Surveys and Surface Preparation ......................................... 8
2.4 CONSTRUCTION.................................................................................................... 10
2.4.1 General................................................................................................................. 10
2.4.2 Materials and Mix Design .................................................................................... 10
2.4.3 Asphalt Plant and Construction Equipment ......................................................... 13
2.4.4 QC/ QA Data ......................................................................................................... 13
2.4.5 Observations and Comments................................................................................ 13
3.0 FRESNO COUNTY, HIGHWAY 33......................................................... 15
3.1 PROJECT LOCATION............................................................................................. 15
3.2 DESIGN CONSIDERATIONS.................................................................................... 15
3.3 PRE- CONSTRUCTION............................................................................................ 18
3.3.1 Deflection Testing and PES Selection .................................................................. 18
3.3.2 Pavement Condition Surveys and Surface Preparation ....................................... 18
3.4 CONSTRUCTION.................................................................................................... 20
3.4.1 General................................................................................................................. 20
3.4.2 Materials and Mix Design .................................................................................... 20
3.4.3 Asphalt Plant and Construction Equipment ......................................................... 23
3.4.4 QC/ QA Data ......................................................................................................... 24
3.4.5 Observations and Comments................................................................................ 26
4.0 MERCED COUNTY, HIGHWAY 140 ..................................................... 27
4.1 PROJECT LOCATION............................................................................................. 27
4.2 DESIGN CONSIDERATIONS.................................................................................... 27
4.3 PRE- CONSTRUCTION............................................................................................ 29
4.3.1 Deflection Testing and PES Selection .................................................................. 29
4.3.2 Pavement Condition Surveys and Surface Preparation ....................................... 32
4.4 CONSTRUCTION.................................................................................................... 32
4.4.1 General................................................................................................................. 32
4.4.2 Materials and Mix Design .................................................................................... 36
4.4.3 Asphalt Plant and Construction Equipment ......................................................... 37
4.4.4 QC/ QA Data ......................................................................................................... 37
4.4.5 Observations and Comments................................................................................ 38
5.0 SAN DIEGO COUNTY, HIGHWAY 75................................................... 39
5.1 PROJECT LOCATION............................................................................................. 39
5.2 DESIGN CONSIDERATIONS.................................................................................... 39
5.3 PRE- CONSTRUCTION............................................................................................ 41
5.3.1 Deflection Testing and PES Selection .................................................................. 41
5.3.2 Pavement Condition and Surface Preparation..................................................... 42
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5.4 CONSTRUCTION.................................................................................................... 42
5.4.1 General................................................................................................................. 42
5.4.2 Materials and Mix Design .................................................................................... 43
5.4.3 Asphalt Plant and Construction Equipment ......................................................... 43
5.4.4 QC/ QA Data ......................................................................................................... 44
5.4.5 Observations and Comments................................................................................ 44
6.0 LASSEN COUNTY, HIGHWAY 395........................................................ 45
6.1 PROJECT LOCATION............................................................................................. 45
6.2 DESIGN CONSIDERATIONS.................................................................................... 45
6.3 PRE- CONSTRUCTION............................................................................................ 47
6.3.1 Deflection Testing and PES Selection .................................................................. 47
6.3.2 Pavement Condition Surveys and Surface Preparation ....................................... 47
6.4 CONSTRUCTION.................................................................................................... 48
6.4.1 General................................................................................................................. 48
6.4.2 Materials and Mix Design .................................................................................... 48
6.4.3 Asphalt Plant and Construction Equipment ......................................................... 48
6.4.4 QC/ QA Data ......................................................................................................... 50
6.4.5 Observations and Comments................................................................................ 50
7.0 SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS............ 51
7.1 SUMMARY ............................................................................................................. 51
7.2 CONCLUSIONS....................................................................................................... 52
7.3 RECOMMENDATIONS............................................................................................ 52
8.0 REFERENCES ............................................................................................ 53
APPENDIX A - Resident Engineers Packet
APPENDIX B - Ventura County, Highway 150 Data
APPENDIX C - Fresno County, Highway 33 Data
APPENDIX D - Merced County, Highway 140 Data
APPENDIX E - San Diego County, Highway 75 Data
APPENDIX F - Lassen County, Highway 395 Data
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LIST OF TABLES
Table 1.1 RAC Warranty Projects ................................................................................................................ 2
Table 2.1 Location and Description of Six PESs for Ventura County, Highway 150 .................................. 3
Table 2.2 Ventura Temperature and Precipitation Data................................................................................ 5
Table 2.3 Ventura 2003 Annual Average Daily Truck Traffic Data ( AADT).............................................. 5
Table 2.4 Ventura Caltrans Pavement Design Alternatives.......................................................................... 6
Table 2.5 Ventura Performance Evaluation Section Locations .................................................................... 8
Table 2.6 Ventura Pre- Overlay Patching ...................................................................................................... 9
Table 2.7 Ventura PES EB1, EB2 and WB3 Associated Paving Details.................................................... 11
Table 2.8 Ventura PES WB4, WB5 and WB6 Associated Paving Details................................................. 12
Table 2.9 Ventura Mix Design Data ........................................................................................................... 12
Table 2.10 Ventura RAC Paving Equipment.............................................................................................. 13
Table 2.11 Ventura QC Testing .................................................................................................................. 13
Table 3.1 Location and Description of Six PESs Selected for Fresno County, Highway 33...................... 15
Table 3.2 Fresno Temperature and Precipitation Data................................................................................ 15
Table 3.3 Fresno 2003 Annual Average Daily Truck Traffic Data ( AADT).............................................. 17
Table 3.4 Fresno Pavement Design Alternatives ........................................................................................ 17
Table 3.5 Fresno Recommended Evaluation Section Locations................................................................. 18
Table 3.6 Fresno Pre- Overlay Roadway Condition .................................................................................... 18
Table 3.7 Fresno PES NB1, NB2 and NB3 Associated Paving Details ..................................................... 21
Table 3.8 Fresno PES SB1, SB2 and SB3 Associated Paving Details ....................................................... 22
Table 3.9 Fresno Mix Design Data ............................................................................................................. 23
Table 3.10 Fresno RAC Paving Equipment................................................................................................ 23
Table 3.11 Fresno Summary AC Plant Production Data ............................................................................ 24
Table 3.12 Fresno Daily Test Result Summaries........................................................................................ 25
Table 4.1 Location and description of six PESs selected for Merced County, Highway 140 .................... 27
Table 4.2 Merced Temperature and Precipitation Data .............................................................................. 27
Table 4.3 Merced 2003 Annual Average Daily Truck Traffic Data ( AADT) ............................................ 27
Table 4.4 Merced Pavement Design Alternatives....................................................................................... 29
Table 4.5 Merced PES Deflection Data Summary ..................................................................................... 32
Table 4.6 Merced Caltrans Plant Inspection Summary............................................................................... 33
Table 4.7 Merced PES Paving Associated Activities and Events ( WB)..................................................... 35
Table 4.8 Merced PES Paving Associated Activities and Events ( EB)...................................................... 36
Table 4.9 Merced Mix Design Characteristics............................................................................................ 37
Table 4.10 Merced RAC Paving Equipment .............................................................................................. 37
Table 4.11 Merced Core Log Data.............................................................................................................. 38
Table 5.1 Location and description of four PESs selected for San Diego County, Highway 75................ 39
Table 5.2 San Diego Temperature and Precipitation Data.......................................................................... 39
Table 5.3 San Diego 2003 Annual Average Daily Truck Traffic Data ( AADT)........................................ 39
Table 5.4 San Diego - Caltrans Pavement Design Alternatives.................................................................. 41
Table 5.5 San Diego Mix Design Characteristics ....................................................................................... 43
Table 5.6 San Diego RAC Paving Equipment............................................................................................ 43
Table 5.7 San Diego Test Strip Production Evaluation Summaries ........................................................... 44
Table 6.1 Location and Description of Nine PESs Selected for Lassen County, Highway 395................. 45
Table 6.2 Lassen Temperature and Precipitation Data ............................................................................... 45
Table 6.3 Lassen 2003 Annual Average Daily Truck Traffic Data ( AADT) ............................................. 45
Table 6.4 Lassen Mix Design Characteristics............................................................................................. 49
Table 6.5 Lassen Paving Equipment........................................................................................................... 49
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LIST OF FIGURES
Figure 1.1 Location of RAC Warranty Projects ........................................................................................... 2
Figure 2.1 Ventura Project Location Plan..................................................................................................... 4
Figure 2.2 Ventura Profile Plot of FWD Deflections and HMA Surface Thickness KP 24.4 and 31.7 ....... 7
Figure 2.3 Ventura Profile Plot of FWD Deflections and HMA Surface Thickness KP 31.7 and 38.6 ....... 7
Figure 3.1 Fresno Project Location Plan..................................................................................................... 16
Figure 3.2 Fresno Northbound Deflection Profile and PES Location......................................................... 19
Figure 3.3 Fresno Southbound Deflection Profile and PES Location......................................................... 19
Figure 4.1 Merced Project Location Plan ................................................................................................... 28
Figure 4.2 Merced West Bound Evaluation Section Locations ( stations) .................................................. 30
Figure 4.3 Merced East Bound Evaluation Section Locations ( stations).................................................... 30
Figure 4.4 Merced West Bound Evaluation Section Locations ( KP) ......................................................... 31
Figure 4.5 Merced East Bound Evaluation Section Locations ( KP)........................................................... 31
Figure 5.1 San Diego Project Location Plan............................................................................................... 40
Figure 5.2 San Diego Deflection Evaluation Plot....................................................................................... 42
Figure 6.1 Lassen Project Location Plan .................................................................................................... 46
Figure 6.2 Lassen Deflection Data Evaluation and Section Locations ....................................................... 47
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1.0 INTRODUCTION
1.1 BACKGROUND AND OBJECTIVES
Between 2002 and 2004 Caltrans built five pilot projects through its rehabilitation program that contain
specifications for rubberized asphalt concrete ( RAC) and include a 5- year warranty on the RAC materials
and workmanship. Originally, it was envisioned that seven projects, CAPM or rehabilitation, would be
constructed using the range of crumb rubber modifier ( CRM) technologies. Candidate technologies
included both the “ wet process” ( rubber- modified asphalt binders produced in the field or at a terminal)
and “ dry process” ( CRM as an aggregate substitute). The overall objective of these RAC warranty pilot
projects was to provide a “ level playing field” for rubber- modified mixes that contain a minimum of 15%
CRM ( by total mass of binder).
Shifting some of the risk to the contractor is fundamental to the warranty concept. As such, two standard
special provisions ( SSPs) were developed which required the contractor to warrant the RAC materials and
performance. In the way of review, performance is measured in terms of the following: rutting, raveling,
flushing, delamination, cracking and potholes.
Ideally, a study of this scope and objective should have been based on a carefully crafted experimental
design to include the full range of CRM technologies with “ test” and “ control” sections constructed in
locations that reflect California’s diverse climatic regimes. Given the political pressure to broaden and
expand Caltrans use of scrap tires in paving applications, a side- by- side comparison of RAC and
conventional asphalt concrete mixes might have generated additional supporting data as to performance
and cost effectiveness of RAC. Unfortunately, attempts to identify projects during the planning and
design stage were unsuccessful due to funding cycles and State budget problems. Furthermore,
unfamiliarity with the CRM technology and/ or uncertainty as to likely success may have compounded the
difficulty in recruiting candidate projects. That said, the expected outcomes of the RAC warranty projects
study include the following:
• Uniform application of the construction and performance criteria by the Resident Engineer ( RE)
in decisions regarding the enforcement of the warranty;
• Objective assessment of RAC performance and cost effectiveness; and
• Efficacy of the warranty specification and the resulting process.
As evident by the title, the emphasis of this report is on the construction- related activities of the RAC
warranty projects. Still, to present a relatively complete compendium of the RAC Warranty project
perspective and data, the information packet developed for the RE overseeing the design and construction
of a RAC warranty project is included as Appendix A. This document provides background information
as well as data collection guidelines and standard special provisions for the warranty ( materials,
workmanship and performance). These data collection guidelines encompass the following: pre-construction;
mix design and laboratory testing; sampling and testing during construction; post-construction
condition; and annual monitoring. As to annual monitoring, performance to date of the RAC
warranty projects is addressed in a companion document [ Caltrans, 2005]. Similarly, some project-specific
design elements, e. g. traffic and environment, are included as they are critical factors in long-term
field pavement performance and evaluation thereof.
As noted previously, only five of the original seven projects were constructed. Table 1.1 provides basic
information on the RAC warranty projects, four of which employed the “ wet process” technology. The
Lassen project was constructed using a terminal blend process. Project locations are shown in Figure 1.1.
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Table 1.1 RAC Warranty Projects
District County Route Region Post Mile P( ProMje) c t LKimiliots Post ( KP) P( rmojie) ct Le( nkgmth)
02 Lassen 395 Mountainous 11.8- 24.8 19.0 – 39.9 13.0 19.9
06 Fresno 33 Central Valley 62.4- 69.4 100.4 – 111.7 7.0 11.3
07 Ventura 150 Coastal 15.2- 24.0 24.4 – 38.6 8.8 14.2
10 Merced 140 Central Valley 27.0- 30.2 43.4 – 48.6 3.2 5.2
11 San Diego 75 Coastal 11.0- 17.4 17.7 – 28.0 6.4 10.3
Figure 1.1 Location of RAC Warranty Projects
1.2 ORGANIZATION OF THE REPORT
Each of the 5 projects is described in individual chapters, i. e., Chapters 2 through 6. Typically addressed
for each project are the following: traffic and environmental data; preconstruction activities ( e. g.,
deflection testing, pavement condition survey, design and surface preparation); construction activities
( e. g., plant, materials, paving equipment, QC/ QA data); post- construction testing and/ or monitoring.
Chapter 7 is an overall summary of observations, conclusions and recommendations. As previously
noted, Appendix A is the information packet developed for the RE overseeing the RAC warranty project.
Appendices B through F contain project- specific information: pre- construction pavement condition
survey data; pre- construction photos and deflection data; construction photos; and materials and testing
data.
Lassen
San Diego
Fresno
Ventura
Merced
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2.0 VENTURA COUNTY, HIGHWAY 150
2.1 PROJECT LOCATION
The Ventura RAC Warranty project ( EA No. 07- 105484) is located along State Highway 150 in District
7, Ventura County, in and beyond Ojai, CA, which is primarily a two- lane roadway. The project extends
14.2 km ( 8.8 miles) from PM 15.0 ( KP24.4 at Loma Drive) to PM 23.9 ( KP 38.6 near the second Lion
Canyon Creek Bridge). The project includes sections of roadway with curb and gutter and on- street
parking within Ojai’s central business district, local arterial and residential areas, and winding climbing
and descending sections in rock- cut and embankment transition areas crossing over the foothill.
Figure 2.1 is a vicinity map illustrating the layout of the project. Construction of the RAC overlay for this
project was completed in October 2002. Table 2.1 identifies the location and provides some basic
information on the six PESs selected for this project.
Table 2.1 Location and Description of Six PESs for Ventura County, Highway 150
PES ID Begin KP Begin PM Overlay or Mill/ Fill
EB1 26.738 16.43 Overlay
EB2 31.446 19.35 Overlay
WB3 38.480 23.72 Overlay
WB4 31.850 19.60 Overlay
WB5 29.436 18.10 Mill/ Fill
WB6 25.652 15.75 Overlay
2.2 DESIGN CONSIDERATIONS
The project is located within the Caltrans “ South Coast” climatic area. Precipitation and temperature data
[ Caltrans, 2004a ( Station # 046399)] are shown in Table 2.2. Traffic [ Caltrans, 2004b] in the vicinity of
the project is characterized in Table 2.3.
Several design alternatives were considered by District 7 staff, as shown in Table 2.4, and a 60 mm gap-graded
rubberized asphalt concrete ( RAC- G) overlay was selected. However, the changing nature and
existing structure of the roadway along the length of the project and constraints for matching existing
adjacent structures resulted in four structural sections, with two different thicknesses of RAC. These
structural sections are listed as shown on the project plans, along with a brief description of the RAC mix
and placement.
1. 60 mm RAC overlay ( single lift of 3/ 4” RAC Type G mix)
2. Cold plane existing AC pavement ( 45 mm max depth) and replace with 45 mm of RAC ( single
lift of 1/ 2” RAC Type G mix)
3. Cold plane existing AC pavement ( 60 mm max depth) and replace with 60 mm of RAC ( single
lift of 3/ 4” RAC Type G mix)
4. 45 mm RAC overlay ( single lift of 1/ 2” RAC Type G mix)
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Figure 2.1 Ventura Project Location Plan
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Table 2.2 Ventura Temperature and Precipitation Data
Element Annual
Average Max Temp (° F) 77.7
Average Min Temp (° F) 45.3
Average Total Precipitation ( in) 21.21
Average Total Snow Fall ( in) 0.1
Average Snow Depth ( in) 0.0
Table 2.3 Ventura 2003 Annual Average Daily Truck Traffic Data ( AADT)
PM KP LEG* Description
Vehicle
AADT
Total
Truck
AADT
Total
Truck %
Total
Vehicle
EAL
1- Way
( 1000)
Year
Ver/ Est
16.57 26.1 B JCT. RTE. 33 NORTH 20000 438 2.19 76 03V
16.57 26.1 A JCT. RTE. 33 NORTH 24400 776 3.18 70 03V
18.86 57.6 B OJAI EAST CITY
LIMITS 7800 112 1.44 13 03V
31.95 57.6 A SANTA PAULA NORTH
CITY LIMITS 3900 149 3.81 22 03V
34.39 55.3 B JCT. RTE. 126, SANTA
PAULA FREEWAY 15200 439 2.89 57 03V
* A leg is given for each count location and is denoted by A, B, or O. For traffic volumes purposes, a highway
intersection or interchange has two legs. According to ascending post miles ( route direction) and a post mile
reference at the center of the intersection or interchange, B= back leg, A= ahead leg, and O= traffic volume is equal
for the back and ahead legs.
Ver= Verified; Est= Estimated
Structural Section 1, the 60 mm RAC overlay was used on most of the project where surroundings are
more rural ( east and west ends). Sections 2 and 3 were used in the “ urban” section of the project, where
milling was required to match overlay surface elevation with the existing profile and grade of adjacent
curb and gutter and other structures. Section 4 was located in one relatively short section in the eastern
outskirts of Ojai, which transitioned to Structural Section 1. The plans included details for transitions in
thickness between the structural sections.
2.3 PRE- CONSTRUCTION
The original 60 mm RAC overlay design thickness was based on a deflection study conducted in October
2000 by Caltrans Office of Materials Engineering & Testing Services ( METS). A condition survey made
at the time of this deflection study revealed the presence of longitudinal cracks, transverse cracks and
isolated areas of alligator ( fatigue) cracking.
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Table 2.4 Ventura Caltrans Pavement Design Alternatives
SOUTHBOUND TRAVELED WAY RECOMMENDATIONS FOR A 10- YEAR TI
1. Test Traffic Numbers = 1- 6 ( 0.014)
2. Area Limits ( TI) = 9.0
3. Average Existing KP ( PM) = 24.1/ 25.6 ( 15.0/ 15.9)
4. Average 80th percentile AC Pavement mm ( ft) = 246mm ( 0.81)
5. Tolerable Percentile mm ( in) = 0.402 ( 0.016)
6. Deflection mm ( in) 0.356 ( 0.014)
Alternate 1 - DGAC Overlay - Conduct a
field- review and locate specific areas of
severe distress such as rutting greater
than 15 mm and/ or loose or spalling
pavement. Dig out and repair the
localized distressed areas and seal all
cracks wider than 5 mm. Then:
1. Place dense graded asphalt concrete
( DGAC) 105 mm ( 0.35 ft) thick
2. This will increase the profile grade
105 mm ( 0.35 ft)
Alternate 2 - RAC- G Overlay - Conduct
a field- review and locate specific areas
of severe distress such as rutting greater
than 15 mm and/ or loose or spalling
pavement. Dig out and repair the
localized distressed areas and seal all
cracks wider than 5 mrn. Then:
1. Place rubberized asphalt concrete
Type G ( RAC- G) 60 mm ( 0.20 ft)
thick This will increase the profile
grade 60 mm ( 0.20 ft)
Alternate 3 - COLD PLANE OUSTING,
REPLACE WITH DGAC - Conduct a
field review and locate specific areas of
severe distress such as rutting greater
than 15 mm and/ or loose or spalling
pavement. Cold plane 90 mm ( 0.30 ft)
and stockpile for future use. Dig out and
repair the localized distressed areas and
seal all cracks wider than 5 mm. Then:
1. Place DGAC 90 mm. ( 0.30 ft) thick
2. This will maintain the existing
profile grade
Alternate 4 - SANH- R/ DGAC - Conduct
a field- review and locate specific areas
of severe distress such as rutting greater
than 15 mm and/ or loose or spalling
pavement. Dig out and repair the
localized distressed areas and seal all
cracks wider than 5 mm. Then:
1. Place a rubberized stress absorbing
membrane interlayer ( SANH- R)
2. Place 60 mm ( 0.20 ft) of DGAC,
this will increase the profile grade
60 mm ( 0.20 ft)
Alternate 5 - SANE- F/ DGAC - Conduct
a field- review and locate specific areas
of severe distress such as rutting greater
than 15 mm and/ or loose or spalling
pavement. Dig out and repair the
localized distressed areas and seal all
cracks wider than 5 mm. Then:
1. Place a fabric stress absorbing
membrane interlayer ( SANH- F)
2. Place 75 = ( 0.25 ft) of DGAC
3. This will increase the profile grade
75 mm ( 0.25 ft)
2.3.1 Deflection Testing and PES Selection
Deflection testing ( FWD) was undertaken by Caltrans in October 2000 prior to construction. Deflections
were measured along the project at a typical spacing of 38m ( 125 ft), alternating from one roadway
direction to the opposite at approximate 0.8 km ( 0.5 mi) intervals. Deflection data are shown graphically
in Figures 2.2 and 2.3. Also, these figures show the HMA surface thickness. From these figures it is
evident that there was considerable variability along the project though there were eight ( 8) areas of
reasonable uniformity: two sections exhibited low sensor- 1 deflections ( less than 10 mils); three exhibited
moderate deflections ( 10 to 15 mils); and three exhibited high deflections ( greater than 15 mils).
Deflection data are shown in Appendix B. In conjunction with the deflection data, pavement condition
surveys conducted and FHWA/ LTPP guidelines, six performance evaluation sections ( PES) were selected
for long- term monitoring as shown Table 2.5.
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0
5
10
15
20
25
30
35
24 25 26 27 28 29 30 31 32
Kilo Post
Deflection ( milli- inches)
EB 1
WB 1
EB 5
WB 5
0
100
200
300
24 25 26 27 28 29 30 31 32
Kilo Post
HMA Thickness ( mm)
EB Thickness
WB Thickness
6 WB
( 25.65- 25.50)
1 EB
( 26.74- 26.89)
5 WB
( 29.44- 29.29)
Discarded
2 EB
( 31.45- 31.60)
Figure 2.2 Ventura Profile Plot of FWD Deflections and HMA Surface Thickness KP 24.4 and 31.7
0
5
10
15
20
25
30
35
31 32 33 34 35 36 37 38 39
Kilo Post
Deflection ( milli- inches)
EB 1
WB 1
EB 5
WB 5
0
100
200
300
31 32 33 34 35 36 37 38 39
Kilo Post
HMA Thickness ( mm)
EB Thickness
WB Thickness
4 WB
( 31.85- 31.70) Discarded
3 WB
( 38.48- 38.33)
Figure 2.3 Ventura Profile Plot of FWD Deflections and HMA Surface Thickness KP 31.7 and 38.6
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Table 2.5 Ventura Performance Evaluation Section Locations
PES
ID
Begin
Kilo Post
Begin
Mile Post
Avg.
Deflection
( mils)
Overlay
or
Mill/ Fill
Condition Description
EB1 26.738 16.425 5 ( low) Overlay
L- M severity longitudinal crack along
construction joint; L- M- H severity fatigue
cracking in left wheel path with water bleeding in
first 100 ft; several M- H severity transverse
cracks.
EB2 31.446 19.350 26 ( high) Overlay
Minimal distress: some L severity longitudinal
cracking ( with some water bleeding) and some L
severity ( onset of) transverse cracking.
WB3 38.480 22.721 14 ( mod) Overlay Minimal distress: some L severity longitudinal
and transverse cracking ( onset)
WB4 31.850 19.601 6 ( low) Overlay Probably milled and filled previously. Minimal
distress – onset of transverse cracking.
WB5 29.436 18.101 26 ( high) M/ F Minimal distress: some L severity transverse
cracking and some signs of flushing in WP.
WB6 25.652 15.750 13 ( mod) Overlay Extensive distress: M- H severity transverse and
block cracking.
Based on the FWD deflection data ( low, moderate and high) each section was visually examined for type
and distribution of distress. Overall, there was a relatively wide range of distress, as summarized in Table
2.5 and detailed in the condition survey data sheets in Appendix B. Photos are also included in Appendix
B. Four of the PESs had minimal distress while other exhibited considerable distress, primarily in the
form of transverse and block cracking of varying severity. As a result of the condition evaluation, one of
the candidate sections ( between KP 29.65 and 29.85 in the EB direction) was discarded because of
variability in distress from one end to the other.
Most of State Highway 150 is on a relatively flat grade with little curvature. However, there is a foothill
located between KP 32.5 and 34.5 which the road climbs over. This area exhibited relatively steep
slopes, sharp curves and switchbacks, and some cut/ fill areas. One candidate PES with relatively uniform
deflections was located in this area between KP 33.78 and 33.94, but had to be discarded due to the slopes
and curves.
The PESs were located in areas where overlay thickness was designated as 60 mm. Only one of the PES
locations, WB5, required cold milling prior to overlay ( i. e., mill and fill). For the remaining PES
locations, only minor pre- overlay repairs were performed prior to the RAC overlay. For each of the RAC
Warranty projects, the extent of pre- overlay repairs needed to make the project warrantable, aside from
those required by the project special provisions, was up to the Contractor. With limited exceptions, such
repairs had to be performed at no additional cost to the State and thus had to be included in the RAC bid
price.
2.3.2 Pavement Condition Surveys and Surface Preparation
Results of the pre- construction manual distress surveys of the PESs, completed in September 2002, are
summarized in Appendix B. Photos of the roadway and cores obtained during FWD testing are also
presented in Appendix B. The existing in- place pavement generally exhibited relatively little distress
( including some moderate to severe transverse cracks scattered throughout and spot locations where
pumping, possible base movement, or flushing was observed) except for the west end of the project
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outside the Ojai city limits, which included PESs EB1 and WB6. The pavement in this area exhibited
longitudinal cracks along construction joints and severe fatigue cracking in the wheel paths with evidence
of base failure and water pumping to the surface. This area is at the base of a long tall hill on the south
side of the roadway, which appears to drain directly into the roadbed and is the likely source of the water
in the pavement structure. Deflections in PES EB1 were lower than would be expected based on the
observed structural distress, but there is an old PCC pavement underneath some of the AC in this section
that would affect FWD measurements. Sections of failed pavement in this area were removed and
replaced with conventional DGAC prior to RAC overlay construction and the locations of the patches are
summarized in Table 2.6.
Some pumping of water was observed in PES EB2, which is near Thacher Creek. There may have been
some previous rehabilitation work in the vicinity of PES WB4 ( KP 31.85) although this has not been
verified.
Information provided to the bidders indicated that the minimum thickness of the existing asphalt concrete
was 203 mm. However, cores taken near the high- severity fatigue cracking areas in the west end
indicated an average asphalt concrete thickness of 138 mm, which may account for the observed
structural distress, alligator cracking and base/ subgrade failure. This discrepancy prompted a change order
to add a 19 to 25 mm thick leveling course from Sta. 244+ 45 to Sta. 261+ 00, which corresponds to the
area where most of the patching was done. Conventional DGAC was used for patching and for the
leveling course. The Engineer noted that the leveling course would correct the surface cross slope and
improve the ride quality of the roadway. It will also improve the pavement structural capacity, but does
not provide a cross section equivalent to the 203 mm thickness that was the basis for the 60 mm overlay
thickness design. Therefore, the long term performance of this section of the project and the two PESs
within it may be affected by structural issues.
Table 2.6 Ventura Pre- Overlay Patching
Date Lane Station Length ( m) Width ( m) Area ( m2)
10/ 21/ 2002 EB 247+ 89 to 248+ 29 40 1.22 48.8
10/ 21/ 2002 EB 248+ 60 to 248+ 75.7 15.1 1.68 25.37
10/ 21/ 2002 EB 249+ 15.12 to 249+ 90.92 75.8 1.22 92.48
10/ 21/ 2002 EB 250+ 01.58 to 250+ 27.66 26.08 1.22 31.82
10/ 21/ 2002 EB 250+ 66 to 250+ 94.44 28.44 1.52 43.23
10/ 21/ 2002 EB 251+ 62 to 254+ 04.32 242.32 1.52 368.33
10/ 22/ 2002 EB 254+ 45.77 to 255+ 18.92 73.15 1.22 89.24
10/ 22/ 2002 EB 255+ 39.65 to 256+ 04.27 64.62 1.22 78.84
10/ 21/ 2002 EB 259+ 41.07 to 259+ 59.05 17.98 1.37 24.63
10/ 21/ 2002 EB 260+ 10.26 to 260+ 40.74 30.48 1.22 37.19
10/ 22/ 2002 EB 261+ 14.5 to 261+ 33.7 19.2 0.91 17.47
10/ 22/ 2002 EB 261.67.87 to 262+ 15.69 47.85 1.22 58.38
10/ 22/ 2002 EB 262+ 33.06 to 262+ 47.39 14.33 1.22 17.48
10/ 22/ 2002 WB 259+ 13.63 to 259+ 66.67 53.04 1.52 80.62
10/ 22/ 2002 WB 259+ 95.63 to 260+ 42.87 47.24 1.52 71.8
WB 256+ 16.27 to 256+ 74.77* 29.25 5.25 153.5
Area was divided in half due to grinding only being 4 inches rather
than 8 inches 58.5 m long/ 2 = 29.25 m. Totals 1239.23
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2.4 CONSTRUCTION
2.4.1 General
Paving was done between 7 p. m. and 6 a. m. from 23 September 2002 through 29 October 2002. Traffic
was controlled with the use of two flag personnel and a pilot car. The RAC- G was placed in windrows,
picked up, and spread with a paving machine. Throughout most of the paving operation, the weather was
relatively mild with temperatures ranging from 80 º F in the early evening to the low to mid 50s º F in the
early morning, which is marginal for RAC paving. However there were nights in late October when air
and pavement temperatures dropped below 50 º F which is colder than the minimum of 55 º F typically
specified for RAC paving and may have affected compaction in some areas. The RAC paving lift
thickness ranged from 45 mm to 60 mm, and paving width varied from 3.4 m and 5.4 m. Approximately
1.7 km of the project included steep grades and tight curves which presented some difficulties when
attempting profilograph measurements. Paving was suspended by the contractor on 4 October due to
issues with the California Profilograph. More detailed accounts of the PES paving, including windrow
and mat temperatures, are shown in Tables 2.7 and 2.8.
2.4.2 Materials and Mix Design
The asphalt rubber binder consisted of 13.9% Pacific tire rubber and 4.1% Pacific high- natural rubber
with 80.0% Greka AR- 4000 Paving asphalt and 2.0% San Joaquin Extender Oil ( all by weight of total
binder). Crumb rubber gradation and physical properties of the asphalt rubber binder are summarized in
Appendix B. The crushed aggregate ( 19 mm, 12.5 mm, 9.5 mm) and dust were provided by Vulcan
Materials from its Palmdale source, California Mine ID 91- 19- 0020. The sand source was Best Rock
from Grimes Canyon, California Mine ID 91- 56- 0010. Two mix designs were performed by Vulcan and
verified by BTC Laboratories and the District 7 Materials Lab, a ½ ” mix for the 45 mm overlay, and a ¾ ”
mix for the 60 mm overlay. Mix design target values for the two RAC- G mixes are shown in Table 2.9.
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Table 2.7 Ventura PES EB1, EB2 and WB3 Associated Paving Details
PES EB1 PES EB2 PES WB3
Paved Sunday October 20, 2002
First load down at 7: 30am on the
intersection of Hwy 33.
At approximately 11: 30- 12: 00, the hot
plant sustained an electrical power
surge, as such AC production ceased.
At 11: 19pm the breakdown roller was
still near PES 0+ 00 the temperature was
1940C
At 11: 48 the finishing roller was still on
the test section and the temp was an
average of 1670C at PES STA 0+ 45
At 11: 53, the finishing roller was off the
0+ 00 mark and the temperature was
1610C
Paved Sunday October 28, 2002
Completed the westbound road to the
west end of the project at
approximately 11: 45.
Contractor paved the Villanova turnout
( south side of road).
Hermosa turnout was not milled
correctly and the RAC was a little
deeper than expected, but it may have
turned out to be a good thing. A water
line was hit somewhere in the upper
section, and water flooded the section.
It estimated to be 10 feet under ground
and the water company hit the line at 6
feet and burst a 600 mm main water
line.
Repairs effected this evening.
Contractor moved to pave the partial
section in town on the westbound lane
slightly west of Shady Lane and
extending through Terrace Gardens
and the vacant lot east of Terrace
Gardens.
The trucks sat for a little while and
when the first load hit the grade, the
temp was only 1350C at 03: 15am.
Monday, September 23, 2002
First load of RAC type ARHM- GG- B,
onsite at 8: 20pm, haul time is between 40
minutes and I hour, paving in the west
bound lane first
Began paving 8: 40pm
Completed 9: 30pm. ( 40 min. pave time).
Small area of diesel spill from the tack truck
within the Performance Evaluation Section
between section stations 1+ 13 and 1+ 15, in
the outer wheel path.
Tack is heavy between PES
STA 1+ 10 and 1+ 12
Some dirt in the mix ( windrow) PES STA
1+ 20 - 1+ 50
BTC Laboratories took cores within the
PES Section limits STA 0+ 30 ( top- lift only)
and 0+ 120 ( 314 mm) in the mid- lane.
Paved approx. 940 meters, 1029 Tonnes of
RAC mix
Stopped paving approx. 4: 30am
STA Screed Mat Lift STA Windrow Mat Lift STA Windrow Mat Lift
0+ 00
0+ 15
0+ 30
0+ 75
1+ 50
1130C
1130C
1160C
1660C
1650C
1500C
75mm
74mm
74mm
72mm
72mm
0+ 00
0+ 45
0+ 75
1+ 50
1500C
1550C
1500C
1550C
1460C
1470C
70mm
70mm
70mm
0+ 30
0+ 75
1+ 50
1510C
1510C
1510C
1460C
1470C
70mm
70mm
65mm
Breakdown roller temp ranges from
111- 1260C
Finishing roller temp ranges from 60-
760C
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Table 2.8 Ventura PES WB4, WB5 and WB6 Associated Paving Details
PES WB4 PES WB5 PES WB6
Paved Tuesday October 01, 2002
First load of RAC onsite at 8: 15pm
Began PES at 3: 15am, completed paving
PES at 4: 10am
Ambient air temperature at 12: 45am was
130C.
Paved approx. 732 meters in the west
bound lane and 798 meters in the east
bound lane tonight, finished paving at
5: 15am.
Profile measurements using the James
Cox & Son model CS8200 computerized
Profilograph.
Performed vertical calibration procedure
and checked tire pressure at 25 psi.
Profile measurements began in the outer
wheel path of the east bound lane at
7: 20pm on the original pavement surface
station 322+ 61 to 317+ 22, began left
wheel path profile at 7: 50pm.
Paved Wednesday October 02, 2002
Began paving at 7: 30pm
Paving went smoothly with the
exception of an occasional lag in RAC
delivery.
Last load onsite at 5: 00am
Paved Thursday, October 03, 2002
Began paving at 7: 30pm
Standing water is present in front of the
Capri Hotel next to the curb and gutter,
contractor paved over it.
It took two passes in the west bound lane
to pave PES due to the street parking in
this area.
Began paving the PES 01: 15am,
Completed paving PES 3: 45am
Ambient air temperature during PES
paving 210C
Variability in the thickness
measurements within the PES due to the
mill and fill against the curb and gutter.
Paving went smoothly with the
exception of an occasional lag in RAC
delivery.
Last load onsite at 5: 30am
STA Windrow Mat Lift STA Windrow Mat Lift STA Windrow Mat Lift
0+ 15
0+ 45
0+ 90
1+ 35
1570C
1570C
1570C
1570C
1480C
1490C
1480C
1480C
65mm
70mm
75mm
75mm
0+ 15
0+ 75
1+ 35
1580C
1550C
1430C
1240C
1440C
75mm
75mm
75mm
0+ 15
0+ 75
1+ 30
1580C
1550C
1430C
1490C
1530C
95mm
80mm
95mm
Table 2.9 Ventura Mix Design Data
Sieve Size ( mm) ½ inch RACP- eGrc ent Pas ¾ si ningc h RAC- G
25 100 100
19 100 98
12.5 96 79
9.5 84 70
4.75 36 32
2.36 16 16
0.6 9 9
0.075 1.8 2
% Asphalt ( by weight of aggregate) 7.8 7.6
LA Rattler ( loss at 100) 9.1 ( 10% max)
LA Rattler ( loss at 500) 35.5 ( 40% max)
Sand Equivalent 64 ( 50 min)
Hveem Stability 29 28
VMA, % 19.9 19.6
Air Voids, % 3.1 3.5
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2.4.3 Asphalt Plant and Construction Equipment
The RAC- G mix was produced by Vulcan Materials in a dryer- drum plant located near Saticoy, CA. FNF
Construction produced the asphalt rubber binder at the Saticoy plant, and placed and compacted the
RAC- G mix on Route 150. The paving equipment utilized on the project is shown in Table 2.10.
Table 2.10 Ventura RAC Paving Equipment
Make Type Model
Merle Husky/ Cat Vibratory Paver Model AP 1055B
Caterpillar Steel Wheel Vibratory Roller ( 25,800 lbs) Model CAT 634C
Ingersoll Rand Steel Wheel Vibratory Roller ( 23,400 lbs) Model DA110
Teamstar 2000 gal Tack Truck
2.4.4 QC/ QA Data
FNF’s quality control plan for the test strip included the following testing: for aggregates, gradation, sand
equivalent and LA abrasion; for the RAC- G mix, asphalt rubber content ( by ignition), Hveem stability
and air void content. Quality control testing requirements for RAC production are summarized in Table
2.11. Available QC and QA data are included in Appendix B. Similarly, results of the limited materials
testing conducted by MACTEC ( formerly Law Crandall), including asphalt rubber binder viscosity, RAC
gradation and theoretical maximum specific gravity, are also shown in Appendix B. The test results
indicate aggregate gradation and asphalt rubber content generally conformed to mix design targets and
respective tolerances.
Table 2.11 Ventura QC Testing
Test Parameter Frequency
Fractured Face
Sand Equivalent
Bulk Density
Hveem Stability
1/ day
Gradation
Max Theoretical Density
Asphalt Content ( by ignition)
1/ 5000 tonnes
In- Place Density continuous
2.4.5 Observations and Comments
The contractor had extensive experience with RAC paving such that other than the usual challenges
associated with nighttime paving, construction generally went smoothly. However there were some
recurring issues with RAC delivery that occasionally interfered with paving operations. Haul time from
Vulcan’s Saticoy plant ranged from 40 minutes to one hour, depending on traffic and route which varied
according to paving location within the project site. At times, the trucks were observed to gang ( i. e.
cluster together) along the route, which caused occasional lags in RAC mix delivery and forced the paver
to stop. Such clustering also caused groups of trucks to arrive at the same time, which meant that some
trucks had to wait to unload. Lags in delivery are noted in Tables 2.7 and 2.8 for three of the six PESs.
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As noted previously, difficulties with the California profilograph measurements occurred on the east end
of the project including the foothill area. The lags in RAC- G mix delivery likely also contributed to
problems with achieving smoothness.
On some nights, ambient temperatures dropped below 55 º F. Temperature measurements of the windrows
and the mat behind the paver generally indicate relatively good temperature control within the PESs, but
there were some deviations over the duration of RAC overlay placement that may have affected
compaction at some locations.
Prior to construction, the Contractor had expressed concerns with the suitability of using RAC- G in on-street
parallel parking areas. MACTEC has been informed that some scuffs and raveling have been
reported in these areas, but does not have specific location information at this time. It should be noted
that there was reportedly some standing water on the pavement in PES 6WB in front of the Capri Hotel
when it was overlaid with RAC- G which may have interfered with bonding of the overlay at this location.
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3.0 FRESNO COUNTY, HIGHWAY 33
3.1 PROJECT LOCATION
The Fresno RAC Warranty project ( EA No. 06- 343534) is a two- lane roadway located along State
Highway 33 in District 6, Fresno County, between Mendota and Firebaugh, CA. The project extends 7.0
mi ( 11.3 km) from PM 62.4 ( KP 100.4 near Bass Avenue) to PM 69.4 ( KP 111.7 near Main Canal
Bridge). The subject section of Highway 33 is located in an agricultural area and also serves as a farm- to-market
route. The RAC overlay for this project was constructed in August 2003. Figure 3.1 is a vicinity
map illustrating the layout of the project. Table 3.1 identifies the location and provides some basic
information on the six PESs selected for this project.
Table 3.1 Location and Description of Six PESs Selected for Fresno County, Highway 33
PES ID Begin KP Begin PM Deflection Level Overlay or Mill/ Fill
NB1 103.31 64.25 High Overlay
NB2 106.37 66.15 Low Overlay
NB3 109.50 68.10 Moderate Overlay
SB1 110.07 68.45 Low Overlay
SB2 107.49 66.85 High Overlay
SB3 105.39 65.54 Moderate Overlay
3.2 DESIGN CONSIDERATIONS
The project area is located within the Caltrans ‘ Central Valley’ climatic area. Precipitation and
temperature data [ Caltrans, 2004a ( Station # 043257)] are shown in Table 3.2. Traffic [ Caltrans, 2004b]
in the vicinity of the project is characterized in Table 3.3.
Table 3.2 Fresno Temperature and Precipitation Data
Element Annual Readings
Average Max Temp (° F) 76.4
Average Min Temp (° F) 50.2
Average Total Precipitation ( in) 10.88
Average Total Snow Fall ( in) 0.1
Average Snow Depth ( in) 0.0
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Figure 3.1 Fresno Project Location Plan
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Table 3.3 Fresno 2003 Annual Average Daily Truck Traffic Data ( AADT)
Post
Mile
Kilo
Post LEG Description
Vehicle
AADT
Total
Truck
AADT
Total
Truck %
Total
Vehicle
EAL
1- Way
( 1000)
Year
Ver/ Est
62.25 100.2 B MENDOTA, JCT.
RTE 180 EAST 5800 1682 29 394 01E
62.25 100.2 A MENDOTA, JCT.
RTE 180 EAST 6400 1280 20 138 01E
70.56 113.5 B FIREBAUGH, 8TH
STREET 8700 1653 19 240 01V
70.56 113.5 A FIREBAUGH, 8TH
STREET 7500 1425 19 207 01E
Ver= Verified; Est= Estimated
Although several design alternatives were considered, as shown in Table 3.4, a 60 mm gap- graded
rubberized asphalt concrete ( RAC- G) overlay was selected.
Table 3.4 Fresno Pavement Design Alternatives
TRAVELED WAY RECOMMENDATIONS FOR A TEN- YEAR TI
1. Design TI ( TI) = 9.5
2. Average 80th percentile AC Pavement mm ( inch) = 0.751mm ( 0.030)
3. Tolerable Percentile mm ( in) = 0.356 ( 0.014)
4. Average AC thickness mm ( in) 0.136 ( 0.45)
Alternate 1 - Cold Plane/ DGAC Overlay Conduct a
field- review and locate specific areas of severe distress
such as rutting greater than 15 mm and/ or loose or
spalling pavement. Mill the existing AC pavement to
remove the chip seal 30 mm ( 0.10 ft) deep and
stockpile for future use. Dig out and repair the localized
distressed areas and seal all cracks wider than 5 mm.
Then: Place 120 mm ( 0.40 ft) of dense graded asphalt
concrete ( DGAC). This will increase the existing
profile grade 90 mm ( 0.30 ft).
Alternate 2 - RAC- G Overlay Conduct a field- review and locate
specific areas of severe distress such as rutting greater than 15 mm
and/ or loose or spalling pavement. Dig out and repair the localized
distressed areas and seal all cracks wider than 5 mm. Then: Place 60
mm ( 0.20 ft) of rubber asphalt concrete- gap graded ( RAC- G). This
will increase the existing profile grade 60 mm ( 0.20 ft)
Alternate 4 - COLD PLANE EXISTING, REPLACE WITH DGAC
This alternative is especially useful to maintain grade at the structures.
Conduct a field- review and locate specific areas of severe distress
such as rutting greater than 15 mm and/ or loose or spalling pavement.
Mill 195 mm ( 0.65 ft) of the existing structural section and stockpile it
for future use. Dig out and repair any remaining localized distressed
areas. Then: Place 195 mm ( 0.65 ft) of DGAC. This will maintain the
existing profile grade.
Alternate 3 - COLD- PIANE EXISTING, REPLACE
WITH HRAC - Conduct a field review and locate
specific areas of severe distress such as rutting greater
than 15 mm and/ or loose or spalling pavement. Mill
the existing AC pavement to remove the chip seal 30
mm ( 0.10 ft) deep and stockpile this material for future
use. Then mill an additional 45mm ( 0- 15 ft) to reclaim
asphalt pavement ( RAP) for hot recycling. Dig out and
repair the localized distressed areas and seal all cracks
wider than 5 mm. Then: Place 150 mm ( 0.50 ft) of hot
recycled asphalt concrete ( HRAC). This will increase
the existing profile grade 75 mm ( 0.25 ft).
Remarks - Prior to choosing hot recycling as the planned alternative, a
preliminary investigation must be made of the existing asphalt
concrete pavement. Depending on the variation in the properties of the
existing in- place material, recycling may not be appropriate. See
Deputy Directive DD- 17 dated November 17, 1993 on Recycling
Asphalt Concrete.
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3.3 PRE- CONSTRUCTION
Based upon the design drawings and verified from pre- construction coring, the existing roadway
consisted of 136 mm of existing asphalt concrete ( Type B) on 365 mm of base. As noted in the previous
section, the contract work included a 60 mm RAC overlay of the existing roadway with new construction
widening of the north bound lane. Additionally, a conventional asphalt concrete leveling blanket was
planned on the south bound lane. The 60 mm RAC overlay design was based on a deflection study
conducted in September 2000 by METS. A pavement condition survey made at the time of the deflection
study revealed the presence of intermittent alligator cracking, rutting and pumping, and nearly continuous
transverse and longitudinal cracking. A chip seal covered the entire project.
3.3.1 Deflection Testing and PES Selection
Pre- construction deflection testing was conducted in mid- March 2003 using a Falling Weight
Deflectometer ( FWD). Based upon the FWD data and pavement condition, six performance monitoring
sections along State Highway 33 were selected, as shown in Figures 3.2 and 3.3. Based upon the average
deflections, two sections were selected within each range: low ( between 9 and 11 mils), medium ( between
14 and 17 mils) and high ( between 22 and 27 mils). Table 3.5 identifies the location and average
deflections within each PES.
Table 3.5 Fresno Recommended Evaluation Section Locations
PES ID Begin Kilo Post Begin Mile Post Avg. Deflection ( mils) Stationing
NB1 103.377 64.249 27.2 ( high) 148+ 17 to 149+ 69
NB2 106.434 66.149 10.5 ( low) 178+ 75 to 180+ 27
NB3 109.570 68.098 14.7 ( med) 210+ 13 to 211+ 65
SB1 110.133 68.448 9.2 ( low) 214+ 24 to 215+ 76
SB2 107.558 66.848 22.6 ( high) 188+ 48 to 190+ 00
SB3 105.462 65.545 16.9 ( med) 167+ 50 to 169+ 02
3.3.2 Pavement Condition Surveys and Surface Preparation
Pre- construction manual distress surveys were completed on each PES in July 2003. Results are detailed
in Appendix C and summarized in Table 3.6. Transverse cracking and large areas of patching were
observed within the project limits. Also evident was wheel path and non- wheel path longitudinal
cracking, though the majority of cracks were sealed. Prior to the RAC overlay a conventional dense-graded
asphalt concrete leveling blanket was placed on the south bound lane. The pre- overlay preparation
work was completed in July 2003.
Table 3.6 Fresno Pre- Overlay Roadway Condition
PES Station General Condition
NB1 148+ 17 to 149+ 69 Large areas of patching
NB2 178+ 75 to 180+ 27 Sealed transverse cracking
NB3 210+ 13 to 211+ 65 Sealed longitudinal and transverse cracking
SB1 214+ 24 to 215+ 76 No visible distress
SB2 188+ 48 to 190+ 00 Right wheel path flushing, left wheel path patching, with water
pumping evident.
SB3 167+ 50 to 169+ 02 Flushing, water pumping and patching with sealed block cracking
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0
5
10
15
20
25
30
35
61 62 63 64 65 66 67 68 69 70
Post Mile
Deflection normalized to 9- kips, mils
Directly Under Loading Plate
Approximate PES Location
Figure 3.2 Fresno Northbound Deflection Profile and PES Location
0
5
10
15
20
25
30
35
61 62 63 64 65 66 67 68 69 70
Post Mile
Deflection normalized to 9- kips, mils
Directly Under Loading Plate
Approximate PES Location
Figure 3.3 Fresno Southbound Deflection Profile and PES Location
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3.4 CONSTRUCTION
3.4.1 General
RAC paving was done during the day between 11 and 21 August 2003. The range in ambient air
temperature was 33 º C to 38oC. The range in pavement surface temperature was 49oC to 60oC.
A pre- construction meeting was held at the District 6 office in Lemoore, CA on 7 August 2003 to discuss
the data collection needs. In attendance were the following:
Jim Wilson
Del Bains
Sarbjit Deol
Lee McClatchey
Clifford Curry
Chris Antonucci
Mark Potter
Caltrans, RE
Caltrans Sr. Engineer
Caltrans Inspector
Lees Paving ( Contractor)
Curry Group ( Contractor)
LAW Crandall
LAW Crandall
Highlights of the meeting were as follows:
• Bains approved McClatchey’s request to use the same mix design as that used for the Menefee
project.
• McClathchey informed Wilson that BSK Labs would be employed for quality control,
specifically to check temperatures, thickness, rolling patterns, and collect samples. Also, he
indicated that test results would be reported to the RE within 4 days of sampling, though he did
not indicate what testing would be performed.
• Bains informed the group that the District 6 laboratory would be conducting tests comparable to
that required for a “ QC/ QA” project.
The first load of RAC hot mix arrived on- site about 0830 on 11 August 2003. The contractor spread tack
at approximately 0.19 liter per meter2 then began paving in the south bound lane, and shoulder ( paving to
the north). Paving equipment consisted of two paving machines, one each for the mainline and shoulder,
and two steel drum vibratory rollers, one per paver. A tandem static steel roller was used for finish
rolling of the shoulder and mainline. The rolling pattern for the mainline and shoulder consisted of five
passes in vibratory mode, and one- full coverage with the static roller.
The paving operation went smoothly, with windrow temperatures reported to be approximately 127 º C to
130 º C. After paving approximately 1,021m the paving operation began paving in the north bound lane
and shoulder ( paving to the north) to even the paved lanes at the end of the day’s construction. Tables 3.7
and 3.8 include paving highlights of the PESs.
3.4.2 Materials and Mix Design
The asphalt rubber binder was produced by FNF Construction, Inc. and consisted of 18% crumb rubber
( 75% scrap tire and 25% high natural rubber) and 2.5% extender oil by weight of total binder. The base
asphalt cement was an AR- 4000 from San Joaquin refinery. Physical properties of the asphalt rubber
binder and blend viscosities as well as crumb rubber gradations are summarized in Appendix C. Table
3.9 includes results of tests on the 19 mm RAC- G mix performed by Caltrans District 6 Materials staff.
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Table 3.7 Fresno PES NB1, NB2 and NB3 Associated Paving Details
PES NB1 PES NB2 PES NB3
Paved August 13, 2003
Daily paving started 08: 50 hrs
PES Paved 14: 00 hrs.
Three boxes of RAC samples, about 75
lb, were obtained at station 148+ 90.
Paved August 15 & 18, 2003
This Performance Evaluation Section is
170 meters north of Shaw Road
intersection. The contractor paved the
taper for the Shaw road turn out, and
stopped 29 meters into PES at Sta.
179+ 07 at 13: 15 hrs., then backed up to
begin paving the south bound lane,
paving to the north. No samples taken.
Aug 18 at 08: 30 beginning at station
179+ 07, 29 m into PES. Four boxes of
RAC samples were collected at station
179+ 72.
There was a 30 minute wait for a haul
truck at station 189+ 20. Paving of SB 2
was completed at 16: 40 hrs
Paved August 20, 2003
First truck onsite at 09: 05 hrs.
Began paving at STA 207+ 40 NB
09: 30 hrs. began paving shoulder of PES,
and began main line paving in NB3 at
09: 45 hrs.
Four boxes of RAC samples collected at
10: 00 hrs at Sta 211+ 00.
Paving completed on PES at 10: 15 hrs.
Air Temp Mat Temp
@ Roller
Windrow
Temp
Air
Temp
Mat Temp @
Roller
Windrow
Temp
Air
Temp Screed Temp Windrow
Temp
330C
380C 90- 1250C > 1250C 330C
380C 90- 1250C 90- 1250C 330C
380C
650C
710C
820C
850C
Windrow Length 92- 100 m
Average one- way haul time 1- 2 hrs
Weather, Clear, dry with a slight breeze
Windrow Length 31- 61 m
Breakdown Roller from Paver 16- 76m
Average one- way haul time 1- 2 hrs
Weather, Clear with a slight breeze
Air Voids 6- 10% in mat
Oil Content 6.5- 7.5%
Stabilities 25, 27
Paving Equipment Setup
Tack Speed @ 0.18925 per m2
Paver Spread rate = 12 mm
SKI Length – 2 @ 9.1 m
Paver installed with Joint Matcher
Dynapac 13 Ton - C522 frequency set to High – reading @ 58
5 Rolling passes in vibratory mode in both directions.
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Table 3.8 Fresno PES SB1, SB2 and SB3 Associated Paving Details
PES SB1 PES SB2 PES SB3
Paved August 20 2003
12: 50 hrs an ambulance drove on the hot
mat in the northbound lane adjacent to
the PES SB1.
15: 00 hrs began paving shoulder on PES
SB1.
Four boxes of RAC samples were
collected on SB1 15: 30 hrs at
STA 215+ 00.
This section was completed at 16: 00 hrs.
Paved August 18, 2003
Collected four boxes of RAC samples
15: 50 hrs at STA 188+ 95
There was a 30 minute wait for a haul
truck at station 189+ 20.
Paving of SB2 was completed at 16: 40
hrs
Paved August 15, 2003
Paved at 14: 00 hrs.
4 boxes of RAC, about 100lb, were
collected within the section limits at
STA 168+ 18.
Contractor completed the paving of this
section at 14: 28 hrs.
Two pavers– mainline and shoulder.
One vibratory roller per.
Air Temp Mat Temp
@ Roller
Windrow
Temp Air Temp Mat Temp
@ Roller
Windrow
Temp Air Temp Mat Temp
@ Roller
Windrow
Temp
330C
380C 90- 1250C 90- 1250C 330C
380C 90- 1250C 90- 1250C 330C
380C 90- 1250C 90- 1250C
Windrow Length 31- 61 m
Breakdown Roller from Paver 16- 76 m
Average one- way haul time 1- 2 hrs
Weather, Clear with a slight breeze
Paving Equipment Setup
Tack Speed @ 0.18925 per m2
Paver Spread rate = 12 mm
Ski length – 2 @ 9.1 m
Paver installed with Joint Matcher
Dynapac 13 Ton - C522 frequency set to High – reading @ 58
5 Rolling passes in vibratory mode in both directions.
Temperatures are surface measurements obtained by infrared device operated by others. Although the
values listed in Tables 3.7 and 3.8 may not accurately represent the temperature inside the windrow or
under the mat surface, these measurements indicate that the mix had cooled considerably from the
consistent 150 to 152 º C surface temperature measured in the haul trucks. Surface cooling creates
temperature segregation that results in differential compaction. The reported mat surface temperatures are
low, which would also be expected to interfere with achieving adequate compaction.
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Table 3.9 Fresno Mix Design Data
Aggregate Gradation Specimen Characteristics
Sieve Size ( mm) Target
Value
Contract
Compliance Detail Result
25.4 100 100 Percent Oil
Content 7.0 7.5 8.0 8.5
19 99 99- 100 Hveem
Stabilometer 36 40 54 46
12.5 84 79- 89 VMA % 17.3 18.5 18.6 18.2
9.5 66 61- 71 Air Voids % 3.6 4.04 3.05 1.62
4.75 34 29- 39 Swell ( mm) Kc 1.0
2.36 21 18- 26 Swell ( mm) Kf 1.0
0.6 11 6- 14
0.075 2 2- 7 Recommended Bitumen Content 7.2 - 7.5 %
Aggregate Quality Tests Percent of Crushed Particles
Test Result Spec. Sieve Size ( mm) % Aggregate Type
Crushed Coarse % 98 90 Bin 5 19mm 21
Crushed Fine % 100 90 Bin 4 12.5mm 23
LA Rattler ( 100 revs) - 10 Bin 3 9.5mm 32
LA Rattler ( 500 revs) 21 40 Bin 2 Dust 10
Coarse
Sand Equivalent, 50 min. 83 50 Bin 1 Sand 14 Fine
Test Number 6- 03- 046, 30 May 2003
3.4.3 Asphalt Plant and Construction Equipment
The equipment utilized is listed in Table 3.10. The RAC- G mixture was supplied by Vulcan Materials’
Friant AC drier- drum plant. An example of Caltrans plant inspection reports is shown in Table 3.11.
Table 3.10 Fresno RAC Paving Equipment
Make Type Model
Ingersoll Rand
Blaw Knox
Paver with CMI Pickup Machine ( 3.7 m mainline
paving) Model 5510
Ingersoll Rand
Blaw Knox
Paver with Lincoln Pickup Machine ( 2.4 m
shoulder paving) Model 4410
Dynapac 13 Ton Tandem Roller Model C522
Dynapac 10 Ton Tandem Roller ( shoulder paving) Model C232
Hyster 10 Ton Tandem Static Roller ( Finish rolling
shoulder and mainline)
Various 33 Double Trailer Belly Dumps
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Table 3.11 Fresno Summary AC Plant Production Data
Base Asphalt Grade Asphalt Modifier Scrap Tire CRM High Natural
79.95% AR400 2.05% 13.86% 4.14%
Plant Production Report Items
Date Details Recording
Asphalt Oil Temp 2040C ( 4000F)
Viscosity Tube 2600, 2800, 3800 cPa
AC Batching Started 07: 00 am
AC Daily production 1970 Tonnes
Production rate 325 Tonnes/ hr
Oil % 7.5 %
August 11, 2003
Mix Temp 1560C ( 3140F)
Truck Mix Temps from 08: 19 hr to 12: 45 hr 152- 1560C
Rate of AR Blend 20 Tonnes/ hr
August 18, 2003
Bin 5
Bin 4
Bin 3
Bin 2
Bin 1
AR Blend wet
19mm Aggregate
12.5mm Aggregate
9.5mm Aggregate
Rock- dust
Sand
6.8%
29%
22%
25%
10%
14%
Rate of AR Blend 20 Tonnes/ hr
Bin 5
Bin 4
Bin 3
Bin 2
Bin 1
AR Blend wet
19mm Aggregate
12.5mm Aggregate
9.5mm Aggregate
Rock- dust
Sand
6.8%
22%
25%
29%
10%
14%
August 20, 2003
Truck Mix Temps from 07: 45 hr to 14: 45 hr 150- 1520C
* Data extracted from Caltrans Plant Inspection Report notes.
3.4.4 QC/ QA Data
BSK Laboratories performed quality control sampling and testing, as well as construction monitoring.
BTC collected and split samples with District 6 lab for purposes of quality assurance testing. Material
testing results are included in Appendix C. Table 3.12 presents the available test results.
Target asphalt rubber binder content was 7.5% by weight of dry aggregate. Results of tests performed by
Caltrans and presented in Table 3.12 yielded asphalt rubber binder contents that ranged from 5.03 to
8.04% ( average 7.03% for 31 tests). Corresponding gradation results could not be located. QC test results
from BSK Laboratories show a narrower range of binder contents, from 5.90 to 7.59%, with an average of
6.9% for 30 tests. Very few individual test results were higher than the mix design target. However 19 of
the total 61 test results reviewed yielded asphalt rubber binder contents less than 6.9%, which raises
concerns about potential for raveling and long- term durability. The minimum asphalt rubber binder
content for RAC- G is set at 7.0% by dry weight of aggregate because RAC- G pavements with lower
binder contents reportedly tend to ravel and have not performed well.
Six sets of two cores each ( 1A- B through 6A- B) were tested for in- place air voids content. Compaction of
sets 1, 2, and 3 was good, with air voids contents ranging from 6.1 to 7.0%. However sets 4 and 5 yielded
relatively high in- place air voids contents ranging from 10.3 to 11.8%, which may be a function of low
placement and compaction temperatures. Core set 6 had marginal air voids contents of 9.2 and 9.8%.
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Table 3.12 Fresno Daily Test Result Summaries
Daily Test Results
Aug 11 Aug 12 Aug 13 Aug 14 Aug 15 Aug 16 Aug 18 Aug 20
Characteristic
PES
Paving PES
Paving PES
Paving
PES
Paving
Sieve Size ( mm)
25.0
19.0
12.5
9.5
4.75
2.36
1.18
0.600
0.300
0.150
0.075
100
100
88
71
37
23
17
11
7
5
3.8
100
99
83
65
32
21
15
9
6
4
3.1
7.98
7.41
7.53
7.33
7.56
7.58
7.35
6.99
6.10
7.30
6.53
7.36
7.00
6.96
7.20
6.42
6.99
7.21
7.40
5.03
6.12
7.03
6.41
7.70
7.27
6.96
5.54
7.58
7.03
8.04
7.06
Bitumen ( CT 382)
6.63
7.40
7.56
7.02
6.80
5.96
6.82 7.20 7.03
7.30 7.37 6.84
6.06
6.37
7.59
CT 382
6.57
7.46
7.50
6.96
6.74
5.90
6.76 7.14 6.97
7.24 7.31 6.78
6.00
6.31
7.53
2.33
2.33
2.31
2.32
2.34
2.35
2.31
2.32
2.28
2.34
2.25
2.28
2.29
2.33
2.30
2.30
2.30
2.29
2.33
2.32
2.32
2.33
2.31
2.32
2.32
2.33
2.29
2.32
2.30
2.34
2.33
Specific Gravity
Briq. ( CT 308)
2.33
RICE Theo. BSG
ASTM 2041 2.402 2.418
20
24
27
33
23
20
38
40
37
34
47
51
48
36
38
40
37
35
37
42
40
34
37
29
21
42
50
25
49
12
31
Stabilometer
25 27 37 40 45 37 40 -
Air Voids
1.40
2.06
2.78
2.37
1.47
1.01
2.98
2.97
5.71
1.74
6.44
4.20
4.22
2.58
3.56
4.49
3.81
3.98
2.06
5.34
4.01
2.51
4.01
2.15
2.64
2.58
5.95
2.27
3.77
0.93
2.47
* Results extracted from Caltrans Test reports TL- 0302
** Contractor Lab BSK results report in bold font
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3.4.5 Observations and Comments
RAC construction appeared to run smoothly. However, if the typical windrow and mat surface
temperatures of 90- 125 º C reported for the PESs are correct, then the RAC- G mix was placed and
compacted at excessively low temperatures in spite of the relatively high ambient and pavement
temperatures. Caltrans specifies a minimum spread temperature of 138 º C, minimum breakdown
compaction temperature of 135 º C, and completion of breakdown compaction before the mix temperature
drops below 121 º C. Windrow temperature readings of 82 º C and 85 º C for PES NB3 are likely erroneous.
At such low temperatures, the RAC- G mix would be very stiff and difficult to spread; workability would
be poor at best and compaction difficult to achieve.
Asphalt rubber binder content results indicate a wide range of contents, nearly one- third of which fell
below the SSP minimum requirement of 7.0% by weight of dry aggregate. This could have major impacts
on performance of the resulting RAC- G pavement. Areas with low binder contents may ravel relatively
quickly, particularly if in- place air voids contents are high. Only two tests yielded binder contents more
than 0.4% higher than the 7.5% design target. The relatively low binder content results do not indicate
potential for flushing or bleeding of the RAC- G mix, which are not typical distresses for RAC- G
pavements. However 18 of 31 laboratory- compacted specimens had mixture voids below 3.0% which
raises some concerns about potential for flushing or bleeding in the overlay.
During performance monitoring, binder content and in- place air voids content should be considered as
factors in the RAC evaluation. The low compaction in some areas of the project is likely to affect long-term
pavement performance, and may increase potential for rutting ( primarily as further consolidation
under traffic) and decrease resistance to moisture damage. Areas with good compaction and sufficient
binder would be expected to perform better and to be less likely to ravel.
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4.0 MERCED COUNTY, HIGHWAY 140
4.1 PROJECT LOCATION
The Merced RAC Warranty project ( EA No. 10- 0A5804) is a two- lane roadway located along State
Highway 140 in District 10, Fresno County, near Merced, CA. The project extends 3.2 miles ( 5.2 km)
from PM 27.0 ( KP 43.4) near McSwain Road to PM 30.2 ( KP 48.6), 0.8 mi ( 1.2 km) east of Applegate
Road. The RAC overlay for this project was constructed in September 2003. Figure 4.1 is a vicinity map
illustrating the layout of the project. Table 4.1 identifies the location and provides some basic
information on the six PESs selected for this project.
Table 4.1 Location and description of six PESs selected for Merced County, Highway 140
PES ID Begin KP Begin PM Deflection Level Overlay or Mill/ Fill
WB1 47.737 29.69 High Overlay
WB2 46.931 29.19 Moderate Overlay
WB3 44.759 27.84 Low Overlay
EB1 44.221 27.50 Low Overlay
EB2 45.258 28.15 High Overlay
EB3 45.894 28.54 Moderate Overlay
4.2 DESIGN CONSIDERATIONS
The project area is located within the Caltrans ‘ Central Valley’ climatic area. Precipitation and
temperature data [ Caltrans, 2004a ( Station # 045532)] are shown in Table 4.2. Traffic [ Caltrans, 2004b]
in the vicinity of the Merced RAC project is characterized in Table 4.3.
Table 4.2 Merced Temperature and Precipitation Data
Element Annual Readings
Average Max Temp (° F) 76.4
Average Min Temp (° F) 47.3
Average Total Precipitation ( in) 12.36
Average Total Snow Fall ( in) 0.0
Average Snow Depth ( in) 0.0
Table 4.3 Merced 2003 Annual Average Daily Truck Traffic Data ( AADT)
Post
Mile
Kilo
Post LEG Description
Vehicle
AADT
Total
Truck
AADT
Total
Truck %
Total
Vehicle
EAL
1- Way
( 1000)
Year
Ver/ Est
16.22 26.1 B JCT. RTE. 165 3400 357 10.5 73 97E
16.22 26.1 A JCT. RTE. 165 3300 383 11.6 95 97V
35.78 57.6 B MERCED, JCT.
RTES. 99/ 59 9800 392 4 80 98V
35.79 57.6 A MERCED, JCT.
RTES. 99/ 59 16500 990 6 167 98V
Ver= Verified; Est= Estimated
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Figure 4.1 Merced Project Location Plan
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Although several design alternatives were considered by District 10 staff, as shown in Table 4.4, a 60 mm
rubberized asphalt concrete ( RAC- G) overlay was selected.
Ten- year design recommendations for a TI = 9.5 were based on the deflection study conducted in July
2000. Additionally, pavement condition survey ( PCS) data, photo logs and longitudinal profile data
( International Roughness Index of 108) were considered. Records indicate that an approximate 30 mm
AC overlay had been placed on the project in late 1997 or early 1998. Cracks reflected through this
overlay within 2 years. A distress survey conducted at the time of the deflection study indicated the
presence of intermittent alligator, transverse and longitudinal cracking with occasional pumping and
rutting.
Table 4.4 Merced Pavement Design Alternatives
10 YEAR REHABILITATION RECOMMENDATIONS
Alternative I Dense Graded Asphalt Concrete ( DGAC) Plus
Rubberized Asphalt Concrete ( Warranty) Overlay – Conduct field
review and locate specific areas of severe distress such as rutting
greater than 15 mm and/ or loose or spalling pavement. Repair the
localized distressed areas and seal all cracks wider than 5 mm.
Then:
Place 45 mm of dense graded AC
1. Place 45 mm of rubberized asphalt concrete ( Warranty)
2. This alternative will increase the existing profile grade 90
mm
Alternative 2 Rubberized Asphalt Concrete ( Warranty)
Overlay - Conduct a field review and locate specific
areas of severe distress such as rutting greater than 15
mm and/ or loose or spalling pavement. Repair the
localized distressed areas and seal all cracks wider than
5 mm. Then:
1. Place 60 mm of rubberized asphalt concrete
( Warranty).
2. This alternative will increase the existing profile
grade 60 mm.
4.3 PRE- CONSTRUCTION
Based upon pre- construction coring the existing pavement structure consisted primarily of 179 mm of AC
over 195 mm of aggregate base ( AB). Core photographs are shown in Appendix D.
4.3.1 Deflection Testing and PES Selection
Prior to construction FWD testing was undertaken in June 2003 as part of the PES selection process.
Deflection data are included in Appendix D. Figures 4.2 to 4.5 illustrate the variation in deflection along
the project route. Figures 4.2 and 4.3 provide deflection profile plots for the EB and WB lanes in
stationing ( meters), whereas Figures 4.4 and 4.5 provide similar data in kilo- post ( KP) units. The
allowable limits reflect a range of relatively uniform deflections within which the PES was chosen.
Tables 4.5 shows the locations of the PESs selected.
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0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
10000 11000 12000 13000 14000 15000
Stations Along Project, ( m)
Defection, ( mils)
Sensor 1
Sensor 8
Trends
Trends
Low Area
Sta. 108+ 21- 115+ 52
High Areas
Sta. 116+ 29- 127+ 46
and
Sta. 138+ 82- 147+ 67
Medium Areas
Sta. 128+ 34- 138+ 01
and
Sta. 148+ 46- 152+ 76
Allowable
Recommended
Figure 4.2 Merced West Bound Evaluation Section Locations ( stations)
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
10000 11000 12000 13000 14000 15000
Stations Along Project, ( m)
Deflection, ( mils)
Sensor 1
Sensor 8
Trends
Trends
Low Area
Sta. 101+ 80- 112+ 25
Medium Area
Sta. 125+ 94- 134+ 83
High Areas
Sta. 113+ 07- 124+ 34
and
Sta. 135+ 62- 147+ 65
Allowable
Recommended
Figure 4.3 Merced East Bound Evaluation Section Locations ( stations)
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0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
43.000 44.000 45.000 46.000 47.000 48.000 49.000
Location Along Project ( KP)
Deflection, ( mils)
Sensor 1
Sensor 8
Trends
Trends
Low Area
KP 44.2- 44.9
High Areas
KP 45.0- 46.1 and
KP 47.2- 48.1
Medium Areas
KP 46.2- 47.2 and
Allowable 48.2- 48.6
Recommended
Figure 4.4 Merced West Bound Evaluation Section Locations ( KP)
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
43.000 44.000 45.000 46.000 47.000 48.000 49.000
Locations Along Project, ( KP)
Deflection, mils
Sensor 1
Sensor 8
Trends
Trends
Low Area
KP 43.5- 44.6
Medium Area
KP 45.9- 46.8
High Areas
KP 44.7- 45.8 and
KP 46.9- 48.1
Allowable
Recommended
Figure 4.5 Merced East Bound Evaluation Section Locations ( KP)
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Table 4.5 Merced PES Deflection Data Summary
Section ID # Deflection Level & Mean Value Section Location
WB1 High ( 28.0 mils) Station 144 + 37 to 142 + 85
WB2 Medium ( 16.0 mils) Station 136 + 31 to 134 + 79
WB3 Low ( 11.0 mils) Station 114 + 58 to 113 + 06
EB1 Low ( 10.0 mils) Station 109 + 20 to 110 + 72
EB2 High ( 26.0 mils) Station 119 + 57 to 121 + 09
EB3 Medium ( 16.0 mils) Station 125 + 94 to 127 + 46
4.3.2 Pavement Condition Surveys and Surface Preparation
As noted previously, the most recent Caltrans pavement condition survey was completed in July 2000 at
which time the distress observed included intermittent alligator, transverse and longitudinal cracking with
occasional pumping and rutting. There are no records available as to the extent of surface preparation
undertaken, which included repair of localized areas of cracking and rutting; grade adjustment; crack
sealing, etc. A conventional DGAC leveling course of varying thickness was placed prior to RAC
construction. Limited pre- construction photos are included in Appendix D.
4.4 CONSTRUCTION
4.4.1 General
A pre- construction meeting was held 12 September 2003 to discuss the data collection needs. In
attendance were the following:
Kewal Virk
Sam Sirang
Dave Bracy
Mike Erickson
Clifford Curry
Andrew Brigg
Mark Potter
Caltrans, RE
Caltrans Inspector
Caltrans Plant Inspector
W. Jackson Baker ( Contractor)
Curry Group ( Contractor)
LAW Crandall
LAW Crandall
Highlights of the meeting were as follows:
• It was agreed that data collection would be overseen by Kewal Virk for distribution to LAW
Crandall.
• Coring by the Curry Group would be done immediately after the construction in coordination
with onsite Caltrans staff.
• PESs limits would be marked by LAW Crandall with wooden stakes.
RAC production for the PESs began on 12 September 20003. Since the plant ran short of binder after
having produced only 175 tonnes, the test strip quantity was reduced from its original 200 tonnes to 150
tonnes. RAC paving began on 15 September 2003 with the arrival seventeen ( 17) double trailer belly
dump trucks hauling RAC mix from the Baker’s LeGrand asphalt plant, about 32 miles from the project
site. Highlights from plant inspection summaries and PESs paving are shown in Tables 4.6 to 4.8. RAC
paving was completed on 19 September 2003.
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Table 4.6 Merced Caltrans Plant Inspection Summary
September 15, 2003
Time Detail
7: 20 Asphalt plant was fired up, with the early mix being wasted
7: 35 Asphalt production
Mix Temperature 163° C ( 375° F)
Cold feed settings used for test strip produced aggregate that was out of spec on 19 mm screen
Bin settings
Bin 5 ( 19mm)- 8%
Bin 4 ( 12.5mm)- 18%
Bin 3 ( 9.5mm)- 47%
Bin 2 ( dust)- 22%
Bin 1 ( sand)- 5%.
8: 00 An aggregate sample was taken at 0800 with 60 Tonnes made to check new cold feed settings.
12: 00 Sample found out of spec on the 19 mm. The sample was split.
Cold feed settings were changed to
Bin 5 - 9%;
Bin 4 - 24%;
Bin 3 – 42%;
Bin 2 - 19%; and
Bin 1 - 5%.
12: 45 Sample was taken - AC plant and binder plant appear to be running smoothly. Total output was 75 loads and 1770
Tonnes ( 1951 tons). Plant ran smoothly throughout the day and no discrepancies were noted.
5: 30 Two batches ( 1000 gallons) of binder had been made. Viscosities were checked 45 minutes after core temp ( 163° C)
had been reached. Viscosities ( centipoise, cPs) were 2500 and 3400. Mix design spec 78% AR- 4000, 15% CRM,
5% high- natural rubber and 2% extender oil. Recipe being used for blending was 79.5% AR- 4000, 14% CRM, 4%
high- natural rubber and 2.5% extender oil. Viscosity of batch 3 was 1900, batch 4 – 2600 cPs, batch 5 – 2200, and
batch 6 – 2300. Blending operations proceeded smoothly and no discrepancies were noted. A total of 10 batches
( 40,000 gallons) were blended. 10,000 gallons of binder remained at the end of the day.
15: 59 The last truck loaded
September 16, 2003
Time Detail
6: 00 AC plant fired up and began keeping mix at 0620. Early material was wasted and silos were cleaned out.
First truck was loaded at 0629. Cold feed settings were bin 5 ( 7/ 8)- 10; bin 4 (- 1/ 2)- 22%; bin 3 ( 3/ 8)- 45%; bin 2
( dust)- 18% and bin 1 ( sand)- 5%. 7% binder was being used. Plant ran continuously throughout Tuesday. No
discrepancies were noted. Contract tester took 5 aggregate samples. Total output was 88 loads and 2104 Tonnes
( 2319.5 tons).
629
Rubber plant began day with 10,000 gallons of binder in two tanks. After cure time at 163° C ( 375° F) viscosity in
each tank was 2,000. Recipe is 79.5% AR- 4000, 14% CRM, 4% high- natural rubber and 2.5% extender oil.
Blending proceeded smoothly and supplied all the binder needed by the AC plant. The viscosity of batch 3 was
2000 and of batch 4 was 2000. A total of 9 batches ( 36,000 gallons) were blended. No binder remained at the end of
the day. One binder sample and one extender oil sample was taken.
15: 59 The last truck loaded
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Table 4.6 Merced Caltrans Plant Inspection Summary ( Cont.)
September 17, 2003
Time Detail
6: 10 Plant fired up. Early material was wasted and silos were cleaned out. Mix was kept until 06: 20
6: 24 First truck was loaded. New cold feed settings were used. They were bin 5 ( 7/ 8)- 10%; bin 4 ( 1/ 2)- 22%; bin 3 ( 3/ 8)-
43%; bin 2 ( dust)- 20%; and bin 1 ( sand)- 5%. Change was made to add more # 200 particles to the mix. 7% binder
was being used. Plant ran continuously throughout Tuesday and no discrepancies were noted. Total output was 87
loads and 2034 Tonnes ( 2242 tons).
Rubber plant began blending with no binder carried over from the previous day. Recipe being used is 79.5% AR-
4000; 14% CRM; 4% high- natural rubber and 2.5% extender oil. Viscosities were checked before any binder was
used. A total of 11 batches ( 45,000 gallons) were blended. The viscosity of batch 1 was 2500; batch 2 – 2700; batch
3 – 2300; batch 4/ 5 – 2500; batch 6/ 7 – 2500 and batch 8/ 9 – 2900. Blending operations proceeded smoothly and no
discrepancies were noted. Total output was 87 loads and 2034 Tonnes ( 2242 tons).
1600 The last truck was loaded
September 18, 2003
Time Detail
6: 53 Plant fired up. Early material was wasted and silos were cleaned out. Mix was kept until 0620
7: 18 First truck was loaded
Transfers were being used. Cold feed settings were bin 5 ( 7/ 8)- 10%; bin 4 ( 1/ 2)- 22%; bin 4 ( 1/ 2)- 22%; bin 3 ( 3/ 8)-
43%; bin 2 ( dust)- 20%; and bin 1 ( sand)- 5%. 7% binder was being used. Plant shut down at 0910 with full silo.
Total output was 24 loads and 534.4 Tonnes ( 589 tons).
No binder was held over from the previous day. Two batches were blended and combined for reaction. The
viscosity was 2000. This was enough binder to meet the need of the AC plant for today. One binder sample was
taken.
15: 28 The last truck was loaded
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Table 4.7 Merced PES Paving Associated Activities and Events ( WB)
PES WB1 PES WB2 PES WB3
Paved Monday September 15, 2003
Contractor began paving PES WBI
( 144+ 37 to 142+ 85) @ 10: 20
Completed paving of PES WBI ( 144+ 37
to 142+ 85) @ 10: 34
RAC lay down temp recorded with
contractor infrared device
One five ( 5) gallon bucket of
RAC material collected from windrow
within PES limits.
Paved Monday September 15, 2003
Contractor began paving PES WB2
( 136+ 31 to 134+ 79) @ 11: 30
Completed paving PES WB2 ( 136+ 31 to
134+ 79) @ 11: 45
One five ( 5) gallon bucket of
RAC material collected from windrow
within PES limits.
Contractor decided to raise RAC mix
temperature at the plant. Delivery temp
recorded @ 1520C
Caltrans Plant Inspector indicated that
QC checks on the 9.5 mm ( 3/ 8")
aggregate showed material was out of
spec.
Plant production stated as 280 Tonnes of
RAC per hour. West bound ( 126+ 20)
mat sanded and opened to traffic.
Contractor paving @ Applegate road
intersection @ 14: 30
PES RAC mix samples from WBI and
WB2 labeled and loaded for shipment to
METS TransLab @ 15: 00
Lay- down paving production ended @
16: 40 ( 126+ 20), excluding roller work.
Tuesday, September 16, 2003
First RAC load onsite @ 07: 15 17
double trailer belly dump trucks hauling
the RAC mix.
Haul time of approximately 45 minutes
Contractor applied tack and began
paving west bound lane
Paving PES WB3 ( 114+ 58 to 113+ 06)
@ 09: 23
Average ground pavement temp 300F
One five ( 5) gallon bucket RAC mix
collected from the windrow ( 113+ 80)
Completed paving PES WB3 @ 09: 30
Sanded and open to traffic 12: 00
Air Temp Mat Temp
@ Roller
Windrow
Temp Air Temp Mat Temp
@ Roller
Windrow
Temp Air Temp Screed
Temp
Windrow
Temp
270C 1030C 1390C 270C 116- 1360C 1520C 310C 1270C 1400C
Mat temp behind paver screed 1270C
Breakdown roller mat temp 1160C
Breakdown roller operating
approximately 10m behind Paver.
Distance from breakdown roller to
paving screed approx 10m
Average one- way haul time 45 min
Finishing Roller @ PES WB2 ( Mat
temp. 520C
Average breakdown roller temp, 1040C
Distance from breakdown roller to
paving screed approx 10m
Finish roller operator stated that the
temperature range of the mat during
finish rolling targeted between 660C and
820C
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Mat temperature for PES WB1 is very low, and may have interfered with compaction. The compaction
temperatures for PES WB2 varied and finish rolling temperature is very low; compaction may also be an
issue for this evaluation section. Table 4.8 indicates similar temperature issues for PES EB1- EB3.
Table 4.8 Merced PES Paving Associated Activities and Events ( EB)
PES EB1 PES EB2 PES EB3
Tuesday, September 16, 2003
Started paving PES EBI
( 109+ 20 to 110+ 72) @ 14: 00
One five ( 5) gallon bucket of the RAC
material collected from windrow
( 110+ 00)
Completed paving @ 14: 15 Section
110+ 00 sanded and opened to traffic
14: 50
Project level and PES digital photos
taken and logged off construction
operations.
Contractor completed mainline paving
and began paving east bound shoulder at
Bert Crane intersection ( paving
eastbound) @ 15: 30
Tuesday, September 16, 2003
Paving PES EB2
( 119+ 57 to 121+ 09) @ 12: 10
One five ( 5) gallon bucket of the RAC
material collected from the windrow
( 120+ 40)
Completed paving PES EB2 @ 12: 20
This section ( 120+ 40) was sanded and
opened to traffic @ 14: 50
Tuesday, September 16, 2003
Start paving the east bound lane
( 127+ 31) @ 11: 44
37m section of PES EB3
( 125+ 94 to 127+ 46) paved
Monday, September 15, 2003.
Construction joint located @ PES. 0+ 15
Contractor paved remaining 15 meters of
P. E. S within approx. 2 min.
One five ( 5) gallon bucket of RAC
material sampled from windrow
( 126+ 01).
Breakdown roller operating approx 30m
behind paving screed
Pavement @ 126+ 01 sanded and opened
to traffic 16: 40
Air Temp Mat Temp
@ Roller
Windrow
Temp Air Temp Mat Temp
@ Roller
Windrow
Temp Air Temp Screed
Temp
Windrow
Temp
310C 1070C 1420C 310C 1140C 1410C 310C 1270C 1430C
Average RAC mat temp behind paving
screed 1290C
Average existing pavement ground temp.
530C
Mat temp during the finish rolling 680C
Average temp. @ Breakdown roller
Distance from breakdown roller to
paving screed approximately 28m.
Average existing pavement ground temp.
500C
Average temp, RAC mat behind the
paving screed 1290C
Distance of breakdown roller 30m
behind paving screed
Existing pavement ground temp. 1130C
RAC mat temp behind paving screed
Average temp @ breakdown roller 980C
4.4.2 Materials and Mix Design
The asphalt rubber binder for the RAC mix was produced by Greka Oil. The binder included 15% scrap
tire crumb rubber, 2% high natural crumb rubber, and 5% extender oil. The design binder content was
7.0% ( by dry weight of aggregate). The target values for the aggregate gradation of the 12.5 mm
maximum RAC- G mix are shown in Table 4.9.
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Table 4.9 Merced Mix Design Characteristics
Aggregate Gradation Specimen Characteristics
Sieve Size ( mm) Target Value
Contract
Compliance Detail Result
25 100 100 Percent Oil Content 7
12.5 95 79 Hveem Stabilometer 36
9.5 81 69 VMA % 15.8
4.75 37 53 Air Voids % 4.2
2.36 22 33 Swell ( mm) Kc 1.1
0.6 13 21 Swell ( mm) Kf 1.1
0.075 5.1 5
0.075 3.3 0- 8
Aggregate Quality Tests Percent Of Crushed Particles
Test Result Spec. Sieve Size ( mm) % Aggregate Type
Crushed Coarse % 97 90 Bin 5 19mm 8
Crushed Fine % 93 90 Bin 4 12.5mm 18
LA Rattler ( 100 revs) 4 10 Bin 3 9.5mm 47
LA Rattler ( 500 revs) 19 40 Bin 2 Dust 22 Coarse
Sand Equivalent, 50 min. 61 50 Bin 1 Sand 5 Fine
4.4.3 Asphalt Plant and Construction Equipment
The equipment utilized is listed in Table 4.10.
Table 4.10 Merced RAC Paving Equipment
Make Type Model
Barber Green Paving Machine Model # BG 260B
Lincoln Pickup Machine Model # 31004
Ingersoll Rand 12 Ton Tandem Vibratory Roller Model # DD 11 OHF
Hypac 12 Ton Tandem Static Roller Model # C778A
Terra Gator Sanding Truck 1603T
Asphalt Trucks 17 Double Trailer Belly Dump Trucks Various
Tack Truck Tandem Axle Unknown
4.4.4 QC/ QA Data
RAC loose mix ( 12 5- gallon buckets) and binder samples ( 1 quart to 1 gallon) were taken at the plant
between 15 and 19 September 2003 and sent to METS TransLab for testing at a later date. Upon
completing the shoulder paving on 17 September 2003, all PESs limits and coring locations were re-marked.
The Curry Group extracted cores on 19 September 2003 and backfilled with a high strength PCC
product. Twelve ( 12) cores were extracted, 2 per PES. Table 4.11 includes the core log data, but no test
data were provided for evaluation of in- place air voids. Construction photos are located in Appendix D.
The lack of typical QC and QA data reflect the difference in the approach to this warranty project.
MACTEC was not authorized to perform any mix testing for information. We have not located any
materials characterization information to use in evaluating the performance of the RAC mix placed at this
site, and urge Caltrans to retain their loose mix samples in case such testing may be needed in the future.
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Table 4.11 Merced Core Log Data
PES Section Stationing Core ID Core Location Total Thickness ( mm)
WB1 144+ 37 to 142+ 85 WB1A 144+ 67 253
WB2 136+ 31 to 134+ 79 WB2A 136+ 66 365
WB2 136+ 31 to 134+ 79 WB2B 134+ 49 254
WB3 114+ 58 to 113+ 06 WB3A 114+ 88 278
WB3 114+ 58 to 113+ 06 WB3B 112+ 76 293
EB1 109+ 20 to 110+ 72 EB1A 109+ 50 321
EB1 109+ 20 to 110+ 72 EB1B 110+ 42 335
EB2 119+ 57 to 121+ 09 EB2A 119+ 87 238
EB2 119+ 57 to 121+ 09 EB2B 120+ 79 308
EB3 125+ 94 to 127+ 46 EB3A 126+ 24 393
EB3 125+ 94 to 127+ 46 EB3B 127+ 16 306
4.4.5 Observations and Comments
Overall, the RAC paving operation appeared to have run smoothly and continuously, however it appears
that there were some issues with relatively low mix temperatures during compaction. The primary delay
in the paving operations was associated with base preparation, i. e., quantity of the conventional DGAC
leveling course mix and the RAC overlay. The delay was related to contractual issues of measurement
and pay. The contractor’s experience with RAC was obvious and led to a smooth operation but
temperature control issues may have adverse effects on performance of the resulting RAC- G pavement.
No test results are available for gradation, binder content, mixture voids, or in- place air voids contents to
incorporate in the performance evaluation.
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5.0 SAN DIEGO COUNTY, HIGHWAY 75
5.1 PROJECT LOCATION
The San Diego RAC Warranty project ( EA No. 11- 230104) is located along the two southbound lanes
and shoulders of State Highway 75, District 11, San Diego County, between Coronado and Imperial
Beach, CA. The project extends 6.4 mi ( 10.3 km) from PM 11.0 ( KP 17.7) to PM 17.4 ( KP 28.0). This
portion of State Route 75 begins at Rainbow Dr in the city of Imperial Beach and ends at the Naval
Amphibious Base Gate 4 in the city of Coronado. There is a cross street with a left turn lane and an
under- crossing within the project limits at approximately station 235+ 80. The RAC overlay for this
project was constructed between April 21 and May 15, 2003. Figure 5.1 is a vicinity map illustrating the
layout of the project. Table 5.1 identifies the location and provides some basic information on the four
PESs selected for this project after the RAC- G was placed.
Table 5.1 Location and description of four PESs selected for San Diego County, Highway 75
PES ID Begin KP Begin PM Deflection Level Overlay or Mill/ Fill
SB- 1 26.50 16.48 Low Overlay
SB- 2 23.07 14.35 High Overlay
SB- 3 20.48 12.74 Moderate Overlay
SB- 4 18.81 11.70 Moderate Overlay
5.2 DESIGN CONSIDERATIONS
The project area is located within the Caltrans “ South Coast” climatic area. Precipitation and temperature
data [ Caltrans, 2004a ( Station # 047740)] are shown in Table 5.2. Traffic [ Caltrans, 2004b] in the vicinity
of the San Diego RAC project is characterized in Table 5.3.
Table 5.2 San Diego Temperature and Precipitation Data
Element Annual
Average Max Temp ( º F) 69.9
Average Min Temp (° F) 56.4
Average Total Precipitation ( in) 10.22
Average Total Snow Fall ( in) 0.0
Average Snow Depth ( in) 0.0
Table 5.3 San Diego 2003 Annual Average Daily Truck Traffic Data ( AADT)
Post
Mile
Kilo
Post Leg Description
Vehicle
AADT
Total
Truck
AADT
Total
Truck %
Total
Vehicle
EAL
1- Way
( 1000)
Year
Ver/ Est
9 14.5 A SD JCT RTE 5 71000 2130 3 151 85V
18.47 29.7 B CORONADO
POMONA AVE 30000 570 1.9 51 86E
19.586 31.5 B JCT RTE 282 32000 768 2.4 46 84V
19.586 31.5 A JCT RTE 282 26000 884 3.4 81 86E
Ver= Verified; Est= Estimated
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Figure 5.1 San Diego Project Location Plan
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Although several design alternatives were considered by District 11 staff, as shown in Table 5.4, a 60 mm
gap- graded rubberized asphalt concrete ( RAC- G) overlay was selected.
Table 5.4 San Diego - Caltrans Pavement Design Alternatives
TRAVELED WAY RECOMMENDATIONS FOR A 10- YEAR TI
1. 10 yr TI = 8.5
2. Average AC Depth = 88 mm / 150 mm cement treated base
3. Average 80th % deflection = 0.254 mm
4. Tolerable deflection = 0.330 mm
5. Reflective depth requirements governs the design
Alternate 1 - Mill 105 mm of the
existing AC and cement treated base;
Remove and replace any failed areas;
Clean and seal cracks equal to or wider
than 6 mm ( 1 / 4"); Place 105 mm
DGAC.
Alternate 2 - Remove and replace any
failed areas; Clean and seal cracks equal
to or wider than 6 mm ( 1 / 4"); Overlay
with 105 mm DGAC.
Alternate 3 - Mill 45 mm of the existing
AC; Remove and replace any failed
areas; Clean and seal cracks equal to or
wider than 6 mm ( 1 / 4"); Place 60 mm
RAC- Type G ( Rubberized Asphalt
Concrete).
Design Notes - Rutting greater than 13 mm and/ or loose pavement identifies locations of specific areas of severe failure. Dig out
and repair these localized areas and seal all cracks wider than 6 mm.
1. For Alternate 1, the shoulder section should be as follows: Mill 30 mm of the existing AC and replace with 30 mm
DGAC. For Alternate 2, the shoulder section should be the same as the traveled way recommendation. For Alternate 3,
the shoulder section should be as follows: Mill 30 mm of the existing AC and replace with 30 mm RAC.
2. The alternates are equal sections and are in no order of preference. Alternate 2 may require shoulder backing.
3. The recommended aggregate grading for DGAC is Type A ( 19 mm maximum, medium).
4. RAC is Type G Rubberized Asphalt Concrete and should conform to the requirements specified for Type A Asphalt
Concrete in Section 39, " Asphalt Concrete", of the Standard Specifications and the most current SSP.
5. The recommendations in this report are valid for a period of 18 months prior to PS& E.
6. Locations of dig outs should be determined 6 to 9 months before construction. The locations and quantities should be
determined by the Project Engineer, Maintenance, or the District Materials Lab.
5.3 PRE- CONSTRUCTION
The 60 mm RAC overlay design was based on a June 2002 deflection study ( Dynaflect JILS- 1313)
conducted by the Office of Materials Engineering & Testing Services personnel. Manual distress data
gathered in conjunction with the deflection testing of 2002 revealed a pavement in poor condition with
continuous transverse cracking and intermittent longitudinal and alligator cracking. A chip seal had been
applied, though the date of its application could not be confirmed. The average thickness of the existing
AC, as determined from pavement cores, was 88 mm over a cement treated base. Although the design
plans indicated that there was 100mm class II base over 457mm of select fill, the contractor found that
there was no Class II base between stations 187+ 78 to 188+ 82 and 191+ 91 to 194+ 23. Also, the
contractor noted the presence of portland cement concrete about 2000ft north of Rainbow Dr and near
station 239+ 15. Pavement condition and core photos may be found in Appendix E.
5.3.1 Deflection Testing and PES Selection
Ideally, FWD testing and a pavement condition survey would have been done immediately preceding
construction to establish the location of the PESs. Unfortunately, due to staffing and budget constraints
as well as construction scheduling, these two critical tasks did not occur in a timely manner. Instead,
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post- construction FWD test data collected in February 2005 and summarized in Figure 5.2 were used to
select the 4 PESs as previously shown in Table 5.1.
0.0
5.0
10.0
15.0
20.0
25.0
11 12 13 14 15 16 17 18
Post Mile
FWD Maximum Deflection ( mils) - Outside SB Lane
Southbound Lane OWP
A
B
C
D
E
F
Figure 5.2 San Diego Deflection Evaluation Plot
5.3.2 Pavement Condition and Surface Preparation
As noted previously, pavement condition survey data were limited to that gathered in June 2002. Dig-outs
and cold milling were done during the first two weeks in April 2003. Information with regard to dig-out
locations or extent of milling operation was not available.
5.4 CONSTRUCTION
5.4.1 General
Paving was completed in 18 production days within a 25- day window from 21 April 2003 to 15 May
2003. The cold plane- grinding operation ran ahead of the paving operation, with the length removed each
production cycle being paved that day. Shoulder paving was done in the same mode. Temperatures
recorded during the day- time paving operation ranged from a morning low of 12oC to late afternoon high
of 19oC. Traffic was controlled with the use of 2 flag personnel and a pilot car. RAC lift thickness
ranged from 45 mm to 60 mm, 3.4 meters wide. The material was generally placed at temperatures above
152oC.
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5.4.2 Materials and Mix Design
The asphalt rubber binder was an AR- 4000 ( Valero Refining, Wilmington, CA) with 20% CRM ( 75%
scrap tire and 25% high natural) from First Nation Recovery, Mecca, CA, and 3% extender oil ( Raffex
170 ACB, Tricor Refining, Oildale, CA). Hanson Industries provided both the coarse and fine aggregate
from its Carroll Canyon and Pala sources, respectively. The asphalt rubber binder was produced by FNF
Construction, Fullerton, CA, and the mix design was developed by Kleinfelder, Inc. San Diego, CA. The
design target values for the 12.5 mm maximum RAC- G mix are shown in Table 5.5.
Table 5.5 San Diego Mix Design Characteristics
Aggregate Gradation Specimen Characteristics
Sieve Size ( mm) Target Value Contract
Compliance Detail Result
25.4 100 100 Percent Oil Content 7.4
19 99 99- 100 Hveem Stabilometer 31
12.5 86 79- 93 VMA % 19.2
9.5 66 59- 73 Air Voids % 5.1
4.75 33 26- 40 Swell ( mm) Kc 1.1
2.36 21 16- 26 Swell ( mm) Kf 1.1
0.6 12 7- 17
0.075 3.3 0- 8
Aggregate Quality Tests Percent Of Crushed Particles
Test Result Spec. Sieve Size ( mm) % Aggregate Type
Crushed Coarse % 98.8 90 Bin 5 19 13
Crushed Fine % 99.5 90 Bin 4 12.5 20
LA Rattler ( 100 revs) 4.1 10 Bin 3 9.5 21
LA Rattler ( 500 revs) 18.9 40 Bin 2 Dust 12
Coarse
Sand Equivalent, 50 min. 54 50 Bin 1 Sand 12 Fine
5.4.3 Asphalt Plant and Construction Equipment
RAC was produced at the CCAC, Otay, CA drum plant. A test strip was placed on 10 April 2003 on the
northbound side between stations 187+ 150 and 198+ 645. The equipment used on the project is listed in
Table 5.6.
Table 5.6 San Diego RAC Paving Equipment
Make Type Model
Merle Husky/ Cat Vibratory Paver Model AP 1055B
Caterpillar Steel Wheel Vibratory Roller Model CAT 364C
Ingersoll Rand Steel Wheel Vibratory Roller Model DD110
Teamstar 2000 gal Tack Truck
Terra Gator Sanding Truck 1603T
R/ T Backhoe w/ Spreader Box
Brace Brace Broom BD250B
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5.4.4 QC/ QA Data
Kleinfelder, Inc. performed extensive QC sampling, testing and construction monitoring. Daily QC test
results are may be found in Appendix E. Results of tests for gradation, asphalt rubber binder content and
relative compaction complied with mix design targets and tolerances with only a few relatively minor
exceptions. Results from the test trip are summarized below in Table 5.7.
Table 5.7 San Diego Test Strip Production Evaluation Summaries
Characteristic Results of QC Tests Spec Limits
Sand Equivalent 62 > 50
Stability 34 > 25
Air Voids (%) 4 7- Mar
Binder Content 6.9 6.9- 7.9
Gradation (% passing)
19mm 97.7 90- 100
9.5mm 68.3 59- 73
4.75mm 30.7 24- 40
2.36mm 18 16- 26
0.6mm 9.7 7- 17
0.075mm 1.4 0- 8
RC (%) 94.3 > 94
5.4.5 Observations and Comments
Due to staffing and budget constraints as well as construction scheduling, no onsite details of PES paving
are available. Although no materials sampling and testing was performed by Caltrans, the Contractor’s
QC results do not indicate any apparent materials problems. A review of Caltrans daily inspection diaries
indicated no unusual occurrences during the paving operation.
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6.0 LASSEN COUNTY, HIGHWAY 395
6.1 PROJECT LOCATION
The Lassen RAC Warranty project ( EA No. 02- 258504) is a two- lane roadway located along State
Highway 395 in District 2, Lassen County, near Doyle, CA. The project extends 13.0 mi ( 20.9 km) from
PM 11.8 ( KP 19.0) to PM 24.8 ( KP 39.9). Figure 6.1 is a vicinity map illustrating the layout of the
project. Table 6.1 identifies the location and provides some basic information on the nine PESs selected
for this project. The modified binder dense- graded asphalt concrete ( MB- D) overlay was constructed in
August 2004. Although paved with the same material, i. e., a 60 mm lift of 19 mm MB- DGAC, the
section between PM 17.6 and PM 22.5 is not covered by the warranty.
Table 6.1 Location and Description of Nine PESs Selected for Lassen County, Highway 395
PES ID Begin KP Begin PM Deflection Level Overlay or Mill/ Fill
NB- 1* 24.89 15.48 Low Overlay
NB- 2* 27.48 17.09 Moderate Overlay
NB- 3 33.91 21.09 High Overlay
NB- 4 34.72 21.59 Moderate Overlay
NB- 5 35.52 22.09 Low Overlay
NB- 6* 36.23 22.53 Moderate Overlay
NB- 7* 37.92 23.58 High Overlay
SB- 8* 38.06 23.67 High Overlay
SB- 9 28.43 17.68 High Overlay
* covered by warranty
6.2 DESIGN CONSIDERATIONS
The project is located within the Caltrans “ High Desert” climatic area. Precipitation and temperature data
[ Caltrans, 2004a ( Station # 042504)] are shown in Table 6.2. Traffic [ Caltrans, 2004b] in the vicinity of
the project is characterized in Table 6.3.
Table 6.2 Lassen Temperature and Precipitation Data
Element Annual
Average Max. Temp (° F) 67.1
Average Min. Temp ( º F) 34.0
Average Total Precipitation ( in) 11.47
Average Total Snow Fall ( in) 22.1
Average Snow Depth ( in) 0.0
Table 6.3 Lassen 2003 Annual Average Daily Truck Traffic Data ( AADT)
Pm Kp Leg Description
Vehicle
AADT
Total
Truck
AADT
Total
Truck %
Total
Vehicle
Eal
1- Way
( 1000)
Year
Ver/ Est
4.615 7.4 B JCT RTE 70 West 9400 975 10.4 226 02E
4.615 7.4 A JCT RTE 70 West 6100 915 15.0 223 02E
29.84 48.0 A Garnier Rd 4500 963 21.4 254 02E
Ver= Verified; Est= Estimated
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Figure 6.1 Lassen Project Location Plan
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6.3 PRE- CONSTRUCTION
The basis for the 60 mm overlay design is assumed to be the deflection testing ( Dynaflect) conducted on
in September 2000 between KP 19.0 and KP 39.1. There was no deflection testing conducted after
surface repair and preparation was completed. In July 2004, the Office of Pavement Rehabilitation
conducted deflections testing ( FWD) test prior to the placement of the MB- D overlay on the non-warranted
section. Deflection data and photos showing pre- overlay pavement condition are provided in
Appendix F.
6.3.1 Deflection Testing and PES Selection
Nine PES sections were established based upon analysis of deflection studies noted in the preceding
section. As shown in Figure 6.2, only five sections are covered by the RAC warranty.
0.0
0.5
1.0
1.5
2.0
2.5
3.0
11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
US 395 Post Mile
Dynaflect Maximum Deflection ( mils) - NB Lane
Warranty Section Contract Change Order Section Warranty
MS 1
MS 5 ( SB)
MS 2 MS 3 MS 4
PES
PES
PES
PES
Northbound PES PES PES PES PES
Southbound
Dynaflect
Sept 2000
FWD Data
( one- tenth)
June 2004
+ Northbound
x Southbound
Low Mod High
Warranty PES 1 PES 2
PES 6
PES 7
PES 8
CCO PES 5 PES 4 PES 3
PES 9
Section Relative Deflection
Type
PES Dir PM Limits Relative
Deflection
Section
Type
1 NB 15.48- 15.57 Low Warranty
2 NB 17.09- 17.19 Mod Warranty
3 NB 21.09- 21.19 High CCO
4 NB 21.59- 21.69 Mod CCO
5 NB 22.09- 22.19 Low CCO
6 NB 22.53- 22.62 Mod Warranty
7 NB 23.58- 23.67 High Warranty
8 SB 23.67- 23.58 High Warranty
9 SB 17.68- 17.59 High CCO
Figure 6.2 Lassen Deflection Data Evaluation and Section Locations
6.3.2 Pavement Condition Surveys and Surface Preparation
Prior to placing the RAC warranty overlay, the contractor placed a scrub seal using a Polymerized
Asphalt Surface System ( PASS) in October 2003. The PASS scrub seal was part of the contractor’s
original repair strategy to seal cracks, prevent reflective cracking, and rejuvenate the existing pavement
surface. Note that the PASS scrub seal was placed only on the warranted sections of the project. With
warm weather in early 2004, the scrub seal bled and created a slippery surface with low skid numbers. To
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remedy the problem, the contractor opted to place a “ Type A” 12.5 mm thin blanket AC overlay using a
PBA binder over the entire scrub seal area. The AC overlay was to serve two purposes: to temporarily
enhance frictional resistance and to act as a leveling course prior to placing the RAC overlay.
As noted previously, an 8- kilometer section ( KP 28.3 to KP 36.3) of this project was also overlaid with
RAC but is not covered by the warranty. District 02 decided to have the contractor overlay the section
“ AS IS” by Contract Change Order ( CCO). The section was excluded from warranty since there was no
repair done to the existing pavement prior to placing the overlay.
6.4 CONSTRUCTION
6.4.1 General
Based on the test strip placed 28 June 2004 the contractor reduced the binder content from 5.3% to 5.1%.
Paving was done between 3: 00 p. m. and 5: 00 a. m, starting on 7 June and was completed on 7 August
2004. Ambient temperatures at the time of paving, ranged from 90° F in the late afternoon to 50° F in the
early morning hour. Traffic control setup included two changeable message signs ( CMS), two flag
personnel, and one pilot car. Paving was from south to north with the sequence as follows: NB mainline,
NB shoulders, SB mainline, and SB shoulders. Mainline paving widths varied from 3.5 m to 3.8 m and
shoulder widths varied from 2.4 m to 2.7 m. Payment for the RAC warranty sections was per square
meter and the non- warranty section was per tonne. Total RAC warranty and non- warranty tonnes placed
were 24,644 and 14,048, respectively.
6.4.2 Materials and Mix Design
Valero Refining provided the AR- 4000 binder modified with 15% crumb rubber as a terminal blend. The
laboratory report and certified batch blend record are found in Appendix F. The source of the aggregate
was the Martin Marietta Pit in Sparks, NV. Lime slurry marination of the aggregate was required. The
worksheet is included in Appendix F. The dense- graded mix design was performed by CGI and verified
by Caltrans District 02 Materials Lab. Target values of the job mix formula and verification data are
listed in Table 6.4. The Contractor’s target values for aggregate gradation generally conform to
requirements for Caltrans Type A 19- mm Maximum, Coarse except that the target value for percent
passing the 4.75 mm ( No. 4) sieve size falls outside the gradation limits presented in Section 39 of the
Caltrans Standard Specifications. The gradation used in verification is finer on most sieve sizes and
conforms more closely to the Caltrans 19- mm Maximum, Medium gradation limits.
6.4.3 Asphalt Plant and Construction Equipment
Atlas Contractors, Inc. supplied the rubberized asphalt concrete from its batch plant in Sparks, NV. Haul
distance from the plant to the project site was approximately 50 miles and haul time was approximately
1 ½ hours. As expected, rush hour traffic tended to increase the haul time. The paving equipment used on
the project is shown in Table 6.5.
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Table 6.4 Lassen Mix Design Characteristics
MIX GRADATION
Sieve Size ( mm) Contractor Mix
Design Target
Caltrans
Verification
Contractor Mix
Design ( Modified)
19 100 100
12.5 78 79
9.5 67 69
4.75 51 53
2.36 34 33
0.6 17 21
0.075 4.9 5
Mix Properties
OBC, BDWA, % 5.3 5.3 5.1
Stability, 37 min. 42 46
VMA,% 15.8
% Air Voids 4.0 5.2
Swell 0.12 0.001
Kc 1.1
Kf 1.1
Aggregate Properties
Crushed Coarse, 90% min. 100 100
Crushed Fine, 90% min 100 100
LA Rattler
@ 100 rev, 10% max. 4 5
@ 500 rev, 25% max. 18 23
Sand Equivalent, 50 min. 67 75
Bin Proportioning
Sieve Size ( mm)
19 30 30 33
12.5 13 13 14
9.5 10 10 10
Dust 22 22 22
Sand 25 25 21
Table 6.5 Lassen Paving Equipment
Terex/ Cedarapids 552 Paver
Terex/ Cedarapids MS 2 pick- up machine
Ingersoll- Rand DD130 ( 13 metric ton) steel- wheel
tandem vibratory roller
Ingersoll- Rand DD110HF ( 11.4 metric ton) steel-wheel
tandem vibratory roller
BearCat 2000- gallon tack distributor truck
Single and double belly- dump trucks
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6.4.4 QC/ QA Data
Quality control sampling, testing and construction monitoring was subcontracted to CGI. RAC samples
were collected behind the paver and split with Caltrans using sample splitters. The tests run by CGI
included gradation, stability, binder content, air void content, sand equivalent, and density. The QC
results in Appendix F indicate that gradation and binder content were, with few exceptions, consistently
within tolerance of the mix design targets. Mixture voids during MB- D mix production were somewhat
low, ranging from 2.2 to 3.3%. It is not clear if the relative compaction results listed are based on the mix
design air voids target or air voids contents measured during production. The former would yield about 5
to 8% in- place air voids, the latter about 3 to 4.5% in- place air voids. In- place air voids contents of 3% or
less may indicate increased potential for rutting. Limited stability test results ranged from 28 to 33, which
exceeds the RAC- G minimum of 23, but is low for a dense- graded mix. Since this was not a “ QC/ QA”
project Caltrans performed similar “ shadow” testing. Also, CGI used the California Profilograph to
assess ride quality, i. e., smoothness, as part of construction QC.
6.4.5 Observations and Comments
During construction of the test strip on 28 June 2004, tearing of the mat was observed. Furthermore,
within six hours of compaction, wheel path rutting was observed that indicates a “ tender” mix. This type
of behavior corresponds with the observed low mixture voids and stability values and relatively high
compaction. Because of the warranty strategy, as opposed to a “ Section 39” project, the RE was not
permitted to take action.
Although the new Cedar Rapids paver was equipped with automated screed control, the contractor chose
to operate it manually because of unspecified difficulties. Additionally, the paving crew did not seem to
communicate effectively and work as “ a team,” perhaps because they had not worked together previously.
Insufficient haul trucks throughout construction made for a “ stop and go” operation, which in some
instances halted the paver for 30 to 45 minutes. “ Stop and go” operation of the paver typically introduces
“ dips” in the pavement that adversely affect smoothness and ride quality. Moreover, prolonged “ stops” of
the paving operation allow the paving material to cool resulting in non- uniform and/ or inadequate
compaction. The RAC warranty specification did not include a smoothness requirement ( CA
Profilograph) since the lift thickness of single lift is less than 75 mm. However, the straightedge
requirement in Section 39- 6.03, “ Compacting,” of the Standard Specifications was used.
Paving in low light conditions presented difficulty in visually assessing mix consistency. Fortunately,
segregated mix observed in the windrow was removed prior to collection by the pick- up machine and
subsequent transfer to the paver hopper.
Although aggregate gradation and binder content were in substantial conformance with mix design
targets, the low mixture voids and relatively stability values raise concerns regarding resistance to rutting.
However if the MB- D mixture does not rut, the low voids may be beneficial in improving resis