LTPP Data Analysis: Influence of Design and Construction Features on the Response and Performance of New Flexible and Rigid Pavements (2005)

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50 CHAPTER 3 - AND EXTENT 3.1 INTRODUCTION This chapter presents a summary on the available data and extent of various performance measures for SPS-1, SPS-2 and SPS-8 experiments. For this study DataPave (Release 17, January 2004) was the primary data source. However, data from previous releases and other sources were used only to supplement the level E data from Release 17. The construction information of each site was obtained from the construction reports. The essential data required for this study can be broadly classified into following categories: • Site Information: site information, construction issues, climatic and traffic data. • Material Data: Material type and properties for various bound and un-bound pavement layers. • Pavement Structure: Layer type and thickness information and other design features such as lane width, shoulder type and dowel bar diameter etc. • Monitoring Data: Longitudinal and transverse profiles, distress and deflections (FWD). • Dynamic Load Response Data: Response data for instrumented sections. 3.2 IDENTIFICATION OF DATA ELEMENTS The relevant variables contained in the SPS-1, SPS-2 and SPS-8 experiments can be divided into: (1) dependent variables, and (2) independent variables. The dependent variables are those used to describe pavement response and performance. Measures of pavement response are those measures that do not cumulate with time. The bulk of pavement responses in these experiments are surface deflections from Falling Weight Deflectometer (FWD) testing. For flexible pavements, FWD testing is conducted in the wheel path and outside the wheel path. For rigid pavements, FWD testing is done at several locations on the PCC slab (see Figure 2-3). Other pavement responses collected in the SPS-1 and SPS-2 experiments include strain data and vertical deflections at various depths. These measurements are only available from the instrumented sections in the Dynamic Load Response (DLR) experiments. DATA AVAILABILITY

51 Measures of pavement performance are those that cumulate with time (e.g., alligator cracking in flexible pavements). These are collected using both manual and automated surveys. The independent variables are those that describe the design and construction factors. These can be divided into: (1) main variables, and (2) exogenous (or confounding) variables. Main variables are those used to specify the design matrices of the respective SPS experiments (e.g., base type). Whereas, the variables that have potential impacts on pavement response and performance but are not controlled in the experiment design were considered as exogenous variables. Exogenous variables that are independent of the main experiment variables are the actual cumulative traffic (KESALs) and age. All other exogenous variables are associated with the main design and construction variables. These include: (1) material properties of the various pavement layers, which constitute the structural factors in the design matrix, and (2) climatic factors, which describe the four climatic zones in the matrix. Table 3-1and Table 3-2 list the relevant independent and dependent variables identified for flexible (SPS-1 and SPS-8) and rigid (SPS-2 and SPS-8) pavements, respectively. After the identification of the relevant variables, a relational database was developed for this research. The development of database is briefly discussed next.

52 Table 3-1 Categorized list of variables for flexible pavements (SPS-1 and SPS-8) Factor Factors Environmental Factors No. of days with Freezing Temperature No. of days with temperature>32oC Annual No. of days with precipitation Annual No. of days with high precipitation Avg. Annual No. of FT cycles FI, Degrees-Days Avg. Annual Precipitation Environmental Zone Avg. Max Temperature, oC, Avg. Min Temperature, oC, Avg. Temperature Range, oC Asphalt Concrete Material Properties AC Grade Target AC Thickness, mm Thickness deviations, mm AC Back calculated Resilient Modulus AC Indirect Tensile Strength after MR Test, kpa AC Indirect Tensile Strength Prior to MR Test, kpa AC Instantaneous Resilient Modulus at 5, 25 and 40 oC, MPa AC Total Resilient Modulus at 5, 25 and 40 oC, MPa Bulk Specific Gravity of AC Mix Water absorption for AC mix aggregate AV% AC% AC mix gradation (all sieves) AC viscosity at 60 oC Aggregate Base Material Properties Target base thickness, mm Thickness deviations, mm Type of base (GB, TB, PATB) Granular base Compaction (Max. density and OMC) Base back calculated resilient modulus Avg. Lab based granular base resilient modulus Base gradation (all sieves) Atterberg Limits (LL, PL, PI) Subgrade Material Properties Subgrade soil type Subgrade Compaction (Max. density and OMC) Subgrade back calculated resilient modulus K1 ,K2 and K5 parameters from the resilient modulus testing for subgrade Avg. Lab based granular base resilient modulus Subgrade gradation (all sieves) Atterberg Limits (LL, PL, PI) Embankment heights (cut or fill) Traffic/Age Cumulative Annual Traffic in KESALs Average Annual Traffic in KESALs Age, Years Performance Alligator Cracking (fatigue) Transverse Cracking Longitudinal Cracking in WP and NWP Bleeding Raveling Roughness (IRI) Rutting Response Deflections Various Deflection Basin Parameters Strains (DLR) Note: The variables in bold are the potential main factors (independent variables) and performance/response (dependent variables). The variables in italics were considered as exogenous factors.

53 Table 3-2 Categorized list of variables for rigid pavements (SPS-2 and SPS-8) Factor Factors Environmental Factors No. of days with Freezing Temperature No. of days with temperature>32oC Annual No. of days with precipitation Annual No. of days with high precipitation Avg. Annual No. of FT cycles FI, Degrees-Days Avg. Annual Precipitation Environmental Zone Avg. Max Temperature, oC, Avg. Min Temperature, oC, Avg. Temperature Range, oC Concrete Material Properties Target PCC Thicknesses, mm Thickness deviations, mm PCC Flexure Strength, psi PCC Compressive Strength, psi PCC Splitting Tensile Strength, psi PCC Mix gradation (all sieves) Aggregate Base Material Properties Target base thickness, mm Thickness deviations, mm Type of base (GB, TB, PATB) Granular base Compaction (Max. density and OMC) Base back calculated resilient modulus Base gradation (all sieves) Atterberg Limits (LL, PL, PI) Subgrade Material Properties Subgrade soil type Subgrade Compaction (Max. density and OMC) Subgrade back calculated resilient modulus Subgrade gradation (all sieves) Atterberg Limits (LL, PL, PI) Embankment heights (cut or fill) Traffic/Age Cumulative Annual Traffic in KESALs Average Annual Traffic in KESALs Age, Years Performance Map Cracking Transverse Cracking Longitudinal Cracking in WP and NWP Longitudinal Spalling Transverse Spalling Pumping Faulting Roughness (IRI) Rutting Response Deflections Various Deflection Basin Parameters Strains (DLR) Note: The variables in bold are the potential main factors (independent variables) and performance/response (dependent variables). The variables in italics were considered as exogenous factors.

54 The data used in this study are “Level E” data from the NIMS database (Release 17.0) for SPS-1, SPS-2 and SPS-8 experiments. All data were extracted from the Release 17.0 CD. The DLR data contained in the DataPave 3.0 database is insufficient and/or inadequate for the analysis. The flowchart describing the process of data extraction from the DataPave Release 17.0 is shown in Figure 3-1. The database has been set up such that the linkage between different data elements is preserved. This was done using ACCESSTM, EXCELTM and SPSSTM software. This relational database allows for describing the data in different ways by combining various factors according to the specific objective of the particular analysis at hand. Tables and figures produced and presented in the data availability section for all experiment designs are example outcomes of this data structure. For cases where multiple data values were available for a data element, the values were averaged to obtain a best estimate. For example, IRI values were averaged over several runs for each section and for a particular date. Deflection measurements were averaged for several load levels for a particular test date. To complement/cross-check the inventory data available in Release 17.0, construction reports for all sections within the SPS-1, -2 and -8 experiments were obtained.

55 Figure 3-1 Data Extraction Process Flow Chart Select the states, experiment type (SPS-1, SPS-2 or SPS-8) Database Exploration and Extraction module Data Type? Performance Data Monitoring Module • Cracking • Rutting • Roughness, IRI • Faulting • Pumping • Spalling Climatic Data Climate Module • Temperatures related data • Precipitation and moisture related data Traffic Data Traffic Module • Historical traffic ESALs • Monitored traffic ESALs and axle load spectrum Response Data Monitoring Module • Deflections • Strains Material Properties/Inventory Testing/SPS Specific Module • Thicknesses • As built type and quality of materials in various pavement layers • Laboratory testing data Select the required Field in each Table to export the necessary data Export the selected data to Excel or Access

56 The construction reports were reviewed for the purpose of obtaining additional detailed information on construction and design features. They also include problems encountered during construction of the SPS pavement sections. Some of these problems have been highlighted in this Chapter. The reports were useful in confirming/disproving conflicting information as well as identifying and explaining some anomalies in the performance. After extraction of all relevant data elements and building the analysis database, the data were reviewed to determine: • the availability of main (design and construction) factors and exogenous (confounding) factors in the identified data element tables, • the availability and extent of response and performance data, • the variability of response and performance measures, and • the variability of the main and exogenous factors. The sections below present the details of the information on the availability and extent of these variables for SPS-1, SPS-2 and SPS-8 experiments, respectively. 3.3 DATA AVAILABILITY IN SPS-1 EXPERIMENT Table 3-3 presents the overall availability of the relevant data elements within the SPS-1 experiment in Release 17.0 of DataPave. This includes both the main design and construction factors as well as other exogenous factors such as traffic, material, and environmental data. The data is presented as a percentage of the total number of sections for the main factors, while for the exogenous factors, data is expressed as a percentage of the total number of sites (states) included in the experimental design matrix. The table shows that the data availability for the main factors is high, while that of the exogenous factors is somewhat lower. In particular, the availability of traffic data (61% for monitored data and 50% for estimated/historical data) is lower than expected and should be improved. It should be noted that traffic estimates from construction reports are available for all but one site [MI (26)]. The availability of relevant data elements is discussed in detail in the subsequent sections.

57 Table 3-3 Summary of SPS-1 data elements availability Data Category Data Type Data Availability, % Site Information Construction Reports Climatic data Virtual Weather Station Annual Temperature Annual Precipitation Automatic Weather Station Monthly Temperature Monthly Precipitation Traffic data Traffic Open date Estimated ESALs Monitored ESALs Axle Load Spectrum 94 100 100 83 83 100 50 61 72 Material Data Asphalt Layer Core Examination Bulk Specific Gravity Max Specific Gravity Asphalt Content Asphalt Resilient Modulus Penetration Viscosity Asphalt Specific Gravity Aggregate Gradation Fine Aggregate Particle Shape Layer Thickness Unbound Base Gradation Subgrade Subgrade Gradation Atterberg Limits Subgrade Modulus 99 89 42 56 15 49 48 47 56 26 100 20 44 56 51 Pavement Structure Layer details Type Representative thicknesses Constructed thicknesses Shoulder information Type Width Thickness 100 100 94 86 86 86 Monitoring** FWD data Deflections Temperature at Testing Backcalculated Moduli Manual Distresses data Longitudinal Profile (IRI) Transverse Profile (Rut Depth) 100 99 6 100 100 100 Note: ** Data is said to be available for a section even if it is available for one survey.

58 3.3.1 General Site Information This section of the report presents the summary of the site identification and location, construction report availability and important dates associated with each of the SPS-1 projects. Also the details of other factors such as climate and traffic, which pertain to a particular site in the SPS-1 experiment, will be discussed in this section. Construction Reports The construction reports have been prepared for each site by the supervisory consultant on the project. These documents contain the details of the construction process from conception to the completion. In addition, these reports presents information on the geometric layout of various sections within a site, construction issues (deviations from the guidelines, if any), traffic, environmental conditions during the construction and material quality control data. These reports are available for all the sites in the SPS-1 experiment except MI (26). A summary of the construction issues at each of 18 sites is given in Appendix A1. These construction issues can be helpful in explaining any poor performance at a particular site. Climate Data The climate data were essentially used in defining boundaries between various climatic regions. The average annual rainfall for each site is considered as discriminating variable between “wet” and “dry” regions, whereas, average annual freezing index is used to locate each site in “freeze” and “no-freeze” regions. The climate data is available form two sources in LTPP database— Automatic Weather Stations (AWS) and Virtual Weather Stations (VWS). The AWS data are collected by a weather station installed at each of SPS-1 experiment site. AWS data for three sites; NV (32), OH (39) and WI (55) are not available in the Release 17.0 of the database. The VWS data are collected from the existing weather stations in the vicinity of a specific site in the SPS-1 experiment. Climate data for all the sites are available from VWS. Therefore, in DataPave, the climate data from VWS have been used to classify each site in a particular climate region/zone.

59 Traffic Data Heavy truck traffic plays a vital role in determining the level of performance in flexible pavements. The traffic data in terms of ESALs per year was obtained from different sources. These sources can be summarized as; • IMS Database: The LTPP IMS database contains traffic data in the following forms; o Monitored Data—data obtained from weigh-in-motion equipment installed at each SPS-1 site. o Estimated Data—data obtained from the DOT’s based on their best estimates from the previous history of the highway section. o Axle Load Spectrum—data obtained from the axle weight data; this is essentially similar to monitored data. The lack of traffic data for various states in the LTPP database has given rise to the quest for reasonable traffic estimates for the missing states. Therefore, other sources were explored, including: • Construction Reports—the estimated design ESALs were taken from construction reports for all the states in the SPS-1 experiment. • FHWA VTRIS database—this was used for estimating the average truck factors for each site, once the ADTT is known from the construction reports, the ESALs per year were estimated for a particular site. • Previous Studies—the available studies on SPS-1 [1, 2] were also used to extract traffic information. Finally, the ESALs per year were estimated by combining the information from all the sources and confidence levels were assigned to the quality of available traffic data. Table 3-4 summarizes the traffic data availability for all the states within the SPS-1 experiment. The importance of traffic data can not be ignored in pavement design and analysis; however; in this research only the traffic estimate is required to neutralize its effects between different sites.

60 Traffic opening date is the date on which a newly constructed project was opened to traffic. This data is available in the database for all sites. The age of a section has been calculated using traffic opening date and corresponding last survey date.

61 Table 3-4 KESAL per year for SPS-1 Experiment KESALs per year LTPP Other Sources Summary Statistics State Code Monitored Estimated Axle Spectrum Const. Reports FHWA- RD-01- 166 NCHRP- 499 Mean Median Std CoV Proposed Confidence Level Remarks Alabama, AL 1 - - - 237 237 - 237 237 - - 237 Low Taken from Construction Report Arizona, AZ 4 236 277 160 185 185 250 214 211 52 24% 214 High Mean value of first four columns Arkansas, AR 5 332 959* 438 170 170 420 475 385 341 72% 385 Med. Median value is adopted by ignoring Const. Report and Estimated Delaware, DE 10 - 414 - 203 203 440 309 309 149 48% 309 Low Mean of Const. Report and Estimated Florida, FL 12 464 - 448 530 1463* 460 481 464 44 9% 464 High Median value of first four columns Iowa, IA 19 29* 171 133 130 130 150 116 132 61 52% 132 Med. Median value by ignoring monitored Kansas, KS 20 203 241 200 268 - 250 228 222 33 14% 228 High Mean value of first four columns Louisiana, LA 22 - - - 524 524 - 524 524 - - 524 Low Only Const. Report Michigan, MI 26 77 - 189 - - 70 133 133 79 59% 189 Med. Only from Axle Load Spectrum Montana, MT 30 - - 81 174 - - 127 127 66 52% 127 Med. Mean value of first four columns Nebraska, NE 31 111 136 87 119 119 100 113 115 21 18% 113 High Mean value of first four columns Nevada, NV 32 525 492 323 560 799 540 475 509 105 22% 475 High Mean value of first four columns New Mexico, NM 35 147 150 125 393 393 150 204 149 127 62% 149 High Ignore Const. Report Ohio, OH 39 390 - 380 507 - 70 426 390 71 17% 390 High Median value of first four columns Oklahoma, OK 40 - - - 281 280 - 281 281 - - 281 Low Only Const. Report Texas, TX 48 - - - 1000 10 - 1000 1000 - - 360 Low *Using construction report traffic data & TF from FHWA Virginia, VA 51 257 917* 187 - 330 454 257 403 89% 257 High Ignore Estimated value Wisconsin, WI 55 - - 134 189 - - 161 161 39 24% 161 Med. Mean value of first four columns Note: * Data considered as outlier

62 3.3.2 Material Data The data pertaining to various material related properties of various pavement layers in the construction of each pavement section have been categorized in material data. The data used in this research mainly include the material properties of the subgrade soil (passing #200 sieve and Atterberg Limits). These data were used to verify the subgrade soil classification (fine or coarse). However, in Release 17.0 of the DataPave this data is only available for 44% and 45% of the sections for soil gradation and plasticity index respectively. Therefore, the materials code available in the materials field was used to get the soil type for each section within SPS-1 experiment. 3.3.3 Design versus Actual Construction Review The SPS-1 experiment is based on the fractional factorial design i.e., all the combinations between levels of various factors were not taken in the design factorial. However, the design matrix was populated with equal number of sites within each climatic zone. To ascertain the homogeneity of the planned experiment with actual sections in the field, in this section the site and structural factors will be compared between as-designed versus as-constructed. First a brief discussion on the construction issues will be presented, and then the deviations in the site and design features within the SPS-1 experiment will be presented. Construction Issues The construction guidelines as discussed in Chapter 2 were specified for each site within the experiment. However, there were some deviations and construction issues related to the some of the sites. This information was obtained from the construction reports. A brief site wise discussion on construction issues can be found in Appendix A1. Some of major construction issues which may have adverse effects on the pavement performance for some particular sites in SPS-1 experiment are summarized below. For SPS-1 site in Kansas [KS (20)], it was mentioned in the construction report that: • The contractor experienced several problems during construction, many of which were caused by the weather. The area experienced much higher than average precipitation during spring 1993, resulting in delays and a wet subgrade. To dry out the subgrade, the contractor was allowed to incorporate fly ash.

63 • During the FWD testing, high deflections were measured in the base in some areas. • There was also segregation in the mix; these problems were “corrected” with adjustments in construction methods. Similarly for Texas [TX (48)], it was found that most of the sections prematurely failed in rutting [3]. This rutting was attributed mainly to asphalt layers because of following reasons: • Excessive asphalt content in the top layer. • Change in the gradation of the aggregates without modifying the asphalt mix. Site Factors The SPS-1 experiment design stipulates that a total of twenty four (24) similar designs will be replicated across eighteen (18) sites in the US. The experiment, designed in a factorial manner to enhance implementation practicality, permits the construction of 12 test sections (0101-0112 or 0113-0124) at one site with the complementary 12 test sections to be constructed at another site within the same climatic region on a similar subgrade type[4]. Table 3-5 lists the intended sites in each subgrade type within the SPS-1 experiment [1, 2]. However, the LTPP IMS data (DataPave 3.0) shows that the sites within the SPS-1 experiment design are not balanced. This deviation was found to be mainly due to: (i) different cutoff values used for categorizing the “wet/dry” and “freeze/non-freeze” environments and, (ii) difference between geographical locations and particular climate at a specific site. The climatic data available for the sites were used to categorize sites into four (4) climatic zones according to LTPP definitions for the climatic zones. All the SPS-1 sites were appropriately classified. Figure 3-2 shows the scatter plot between rainfall and freezing Index (FI) for all sites in SPS-1 experiment. The as-constructed location of the different sites is shown in Table 3-6. Further, it can be seen that there are more sites available in wet climate (8 and 6 in “freeze” and “no-freeze” respectively). There are only four sites in the dry climate (DF and DNF zones); the two sites present in DF zone are constructed on a coarse subgrade type. Therefore, the effect of subgrade type can not be determined in DF zone. These deviations are expected to affect the analysis (the experiment design will become unbalanced). Consequently, the analysis of the SPS-1 experiment design mainly focuses on the WF and WNF zones.

64 Table 3-5 Intended SPS-1 site factorial [1] Wet Dry Subgrade Type Freeze Non-Freeze Freeze Non-Freeze Total IA, OH AL KS NM Fine VA, MI LA NE OK 10 DE FL NV TX Coarse WI AR MT AZ 8 Total 6 4 4 4 18 0 200 400 600 800 1000 1200 Avg. Annual Freezing Index (C-day) 200 400 600 800 1000 1200 1400 1600 A vg . A nn ua l R ai nf al l ( m m ) 1 4 5 10 12 19 20 22 26 30 31 32 35 39 40 48 51 55 Figure 3-2 Scatter plot showing site distribution by climate WF WNF DF DNF

65 Table 3-6 SPS-1 site factorial — From DataPave 3.0 Weta Dryb Subgrade Type Freezec Non-Freezed Freeze Non-Freeze Total IA (19) OH (39) AL (1) - NM (35) Fine KS (20) MI (26) NE (31) LA (22) VA (51) - - 9 DE (10) FL (12) TX (48) NV (32) - Coarse AR (5) WI (55) OK (40) MT (30) AZ (4) 9 Total 8 6 2 2 18 Note: a. Wet Regions — Average Annual Rainfall > 20 inches (508 mm) b. Dry Regions — Average Annual Rainfall < 20 inches (508 mm) c. Freeze Regions — Average Annual Freezing Index > 83.3 oC-day (150 oF-day) d. Non-Freeze Regions — Average Annual Freezing Index < 83.3 oC-day (150 oF-day)

66 Design Factors The design or structural features which are considered to be the main experimental factors in the SPS-1 experiment are: • AC Thickness (4 versus 7 inches) • Base Thickness (8, 12 and 16 inches) • Base Type (DGAB, ATB and ATB/DGAB) • Drainage (No or Yes) Each of the above features will be reviewed in this section to identify any deviation from the target values. The asphalt and base layers were targeted for 2 and 3 thickness levels respectively; however, the construction of these target values may contribute variability in these thicknesses. The amount of variability introduced by the construction and how this variability can affect the analysis will be discussed in this section. Layer Thickness The as-constructed asphalt and base thickness were compared with their respective target thickness. The results of this comparison are given below. AC Thickness: The SPS-1 experiment has two levels of HMA surface thickness — 4-inch (102 mm) and 7-inch (178 mm). The allowable deviation from the target HMA surface thickness according to guidelines is 6.53 mm. Table 3-7 shows the summary statistics for each level of asphalt thickness. Among sections with target thickness of 102 mm, the as-constructed thicknesses between all 18 sites has a coefficient of variation (CoV) of 12.7% with about 43% of the sections within the allowable deviations and 49% sections having more asphalt thickness than the allowable upper limit. Only 7.5% of the sections have slightly less asphalt thickness than the allowable lower limit. Similarly, for the pavement designs which were targeted for 178 mm, the as-constructed asphalt thickness has a CoV of about 9% with about 78% of the sections meeting the tolerable limits or having higher asphalt thickness than the upper limit. The frequencies of as-constructed asphalt thickness are shown in Figure 3-3, whereas Figure 3-4 shows the scatter of asphalt thickness in different sites within the SPS-1 experiment. The overall low values of CoV for as-constructed asphalt thickness between all sites show that the asphalt thickness was quite well controlled during construction, especially for 7-inch (178 mm)target HMA surface thickness.

67 Base Thickness: The SPS-1 experiment has three levels of base thickness— 8-inch (203 mm), 12-inch (305 mm) and 16-inch (406 mm). The allowable deviation from the target base thickness according to guidelines is 12.7 mm. The summary statistics for as-constructed base thicknesses at each level are shown in Table 3-7. Among sections with target thickness of 203 mm, the as- constructed thicknesses between all 18 sites has a coefficient of variation (CoV) of 10.1% with about 65% of the section within the allowable deviations and 25.3% sections having more base thickness than allowable higher limit. Only 9.2% of the sections have slightly less thickness than allowable lower limit. Similarly, the designs which were targeted for 305 mm, the as- constructed thickness has a CoV of 4.7% with about 79% of the sections meeting the tolerable limits or either have higher thickness than the higher limit. The designs with targeted 406 mm of base thickness have a CoV of 4.6% with about 22% of the section having slightly less thickness than the lower limit. The frequencies and scatter plots of as-constructed base thicknesses are shown in Figure 3-5. The overall low values of CoV for as-constructed base thickness for all levels between all sites show that the base thickness was also quite well controlled during the construction. The variations between as-constructed and target thickness for asphalt and base within some sites have shown significant difference (see Figure 3-4 and Figure 3-5). This variation may affect the pavement performance for these sites; therefore, the deviations between target and actual thickness were taken as covariates in the analysis of variance.

68 Table 3-7 Summary of comparison between target and as-constructed layer thickness Comparison with allowable deviation Pavement Layer / Target thickness Count Mean (inches) Std CoV (%) < Lower limit With tolerable limit > Upper limit AC Layer 4-inch (102 mm) 7-inch (178 mm) 106 106 4.38 7.12 0.557 0.654 12.7 09.2 < 3.75=7.5% < 6.75=21.7% 3.75-4.25=43.4% 6.75-7.25=37.7% >4.25=49.1% >7.25=40.6% Base Layer 8-inch (203 mm) 12-inch (305 mm) 16-inch (406 mm) 87 89 36 8.26 11.9 15.9 0.84 0.56 0.74 10.1 04.7 04.6 <7.50=9.2% <11.5=21.3% <15.5=22.2 7.50-8.50=65.5% 11.5-12.5=66.3% 15.5-16.5=61.1% >8.50=25.3% >12.5=12.4% >16.5=16.7% 0 5 10 15 20 25 30 35 40 45 -3 3- 3. 5 3. 5- 4 4- 4. 5 4. 5- 5 5- 5. 5 5. 5- 6 AC Thickness (inches) N o. o f s ec tio ns 0% 20% 40% 60% 80% 100% Pe rc en t s ec tio ns b el ow (a) Cumulative frequency for actual AC thickness— 4”target 0 5 10 15 20 25 30 35 -5 5- 5. 5 5. 5- 6 6- 6. 5 6. 5- 7 7- 7. 5 7. 5- 8 8- 8. 5 8. 5- AC Thickness (inches) N o. o f s ec tio ns 0% 20% 40% 60% 80% 100% Pe rc en t s ec tio ns b el ow (b) Cumulative frequency for actual AC thickness— 7”target Figure 3-3 Frequency plot for actual AC thickness

69 State A C T hi ck ne ss ( in ch es ) 555148403935323130262220191210541 6.0 5.5 5.0 4.5 4.0 3.5 4 (a) Scatter plot of actual AC Thickness — 4”target State A C T hi ck ne ss ( in ch es ) 555148403935323130262220191210541 10 9 8 7 6 5 4 7 (b) Scatter plot of actual AC Thickness — 7”target Figure 3-4 Scatter plot for actual AC thickness by site

70 0 5 10 15 20 25 30 35 40 -6 .5 6. 5- 7 7- 7. 5 7. 5- 8 8- 8. 5 8. 5- 9 9- 9. 5 9. 5- Base Thickness (inches) N o. o f s ec tio ns 0% 20% 40% 60% 80% 100% Pe rc en t s ec tio ns b el ow (a) Cumulative frequency for actual base thickness— 8”target State B as e T hi ck ne ss ( in ch es ) 555148403935323130262220191210541 13 12 11 10 9 8 7 6 8 (b) Scatter plot of actual base Thickness — 8”target 0 5 10 15 20 25 30 35 -1 0. 5 10 .5 -1 1 11 -1 1. 5 11 .5 -1 2 12 -1 2. 5 12 .5 -1 3 13 -1 3. 5 13 .5 - Base Thickness (inches) N o. o f s ec tio ns 0% 20% 40% 60% 80% 100% Pe rc en t s ec tio ns b el ow (c) Cumulative frequency for actual base thickness— 12”target State B as e T hi ck ne ss ( in ch es ) 555148403935323130262220191210541 14 13 12 11 10 12 (d) Scatter plot of actual base Thickness — 12”target 0 2 4 6 8 10 12 14 -1 4. 5 14 .5 -1 5 15 -1 5. 5 15 .5 -1 6 16 -1 6. 5 16 .5 -1 7 17 -1 7. 5 17 .5 - Base Thickness (inches) N o. o f s ec tio ns 0% 20% 40% 60% 80% 100% Pe rc en t s ec tio ns b el ow (e) Cumulative frequency for actual base thickness— 16”target State B as e T hi ck ne ss ( in ch es ) 555148403935323130262220191210541 20 18 16 14 12 10 16 (f) Scatter plot of actual base Thickness — 16”target Figure 3-5 Frequency and scatter plots for actual base thickness

71 3.3.4 Extent and Occurrence of Distresses This section of the report presents the availability of the pavement performance data for all SPS-1 sites. The availability of the performance data will be discussed in terms of extent and occurrence of a particular performance measure. The pavement performance measures considered in this research include: a. Fatigue cracking (total area, sq-m) b. Longitudinal cracking-WP (length, m) c. Longitudinal cracking-NWP (length, m) d. Transverse cracking (length, m) e. Rut depth (mm) f. Roughness (IRI, m/km) It should be noted that various severity levels of the first four distresses were simply added to calculate the total cracking area or length. The change in roughness (∆IRI= IRIlatest- IRIo) was considered in the roughness analysis. The extent (mean distress) and occurrence (frequency of distress) are presented below for each performance measure based on data from DataPave (Release 17.0). Fatigue Cracking Figure 3-6 shows the occurrence of fatigue cracking in all SPS-1 sections by design and site factors. Based on the latest available data (Release 17.0), about 62% of the sections have exhibited some level of fatigue cracking whereas about 38% of the sections have not yet shown any signs of fatigue [see Figure 3-6 (d)]. Similarly, Figure 3-7 presents the extent of fatigue cracking by design and site factors. The distribution of latest age for all sections is presented in Figure 3-8. It shows that about 10% of the sections can be considered as young (< 3 years), while the overall average for latest age of all sections is 6.5 years. Figure 3-9 shows the variation of fatigue cracking within each site of the SPS-1 experiment.

72 40% 45% 50% 55% 60% 65% 70% 4 7 DG AB AT B AT B/ DG AB 8 12 16 ND D Design Factors P e r c e n t o f s e c t i o n s c r a c k e d (a) Extent of occurrence of fatigue cracking by design factors 40% 50% 60% 70% 80% 90% 100% WF WNF DF DNF F C Site Factors P e r c e n t o f s e c t i o n s c r a c k e d (b) Extent of occurrence of fatigue cracking by site factors 0 10 20 30 40 50 60 70 80 90 -0 0-2 5 25 -50 50 -75 75 -10 0 10 0-1 25 > 1 25 Fatigue Cracking, sq-m N u m b e r o f s e c t i o n (c) Frequency of sections for fatigue cracking 38% 35% 11% 5% 2% 3% 6% -0 0-25 25-50 50-75 75-100 100-125 > 125 (d) Distribution of sections for fatigue cracking Figure 3-6 Occurrence of fatigue cracking — SPS-1 experiment

73 0 10 20 30 40 50 60 70 4 7 DG AB AT B AT B/ DG AB 8 12 16 ND D Design Factors A v e r a g e f a t i g u e c r a c k i n g , s q - m (a) Average fatigue cracking by design factors 0 10 20 30 40 50 60 70 80 WF WNF DF DNF F C Site Factors A v e r a g e f a t i g u e c r a c k i n g , s q - m (b) Average fatigue cracking by site factors Figure 3-7 Extent of fatigue cracking— SPS-1 experiment 0 10 20 30 40 50 60 70 80 90 < 3 3-5 5-7 7-9 9-11 Age (years) N u m b e r o f s e c t i o n (a) Frequency of sections for latest age 10% 22% 18% 39% 11% < 3 3-5 5-7 7-9 9-11 (b) Distribution of sections for latest age Figure 3-8 Age distribution of all cracking distresses — SPS-1 experiment

74 State Fa ti gu e C ra ck in g (s q- m ) 555148403935323130262220191210541 350 300 250 200 150 100 50 0 116 114 120 113 113 1072 102 107 102 119 116 Figure 3-9 Fatigue cracking by site — SPS-1 experiment

75 Longitudinal Cracking-WP Figure 3-10 shows the occurrence of longitudinal cracking-WP in all SPS-1 sections by design and site factors. Based on the latest available data (Release 17.0), about 46% of the sections have exhibited some level of longitudinal cracking whereas about 54% of the sections have not yet shown any signs of cracking [see Figure 3-10 (d)]. Similarly, Figure 3-11 presents the extent of longitudinal-WP cracking by design and site factors. Figure 3-12 shows the variation of longitudinal cracking-WP within each site of the SPS-1 experiment. Longitudinal Cracking-NWP Figure 3-13 shows the occurrence of longitudinal cracking-NWP in all SPS-1 sections by design and site factors. Based on the latest available data (Release 17.0), about 68% of the sections have exhibited some level of cracking whereas about 32% of the sections have not yet shown any signs of cracking [see Figure 3-13(d)]. Similarly, Figure 3-14 presents the extent of longitudinal- NWP cracking by design and site factors. Figure 3-15 shows the variation of longitudinal cracking-NWP within each site of the SPS-1 experiment. Transverse Cracking Figure 3-16 shows the occurrence of transverse cracking in all SPS-1 sections by design and site factors. Based on the latest available data (Release 17.0), only 35% of the sections have exhibited some level of transverse cracking whereas about 65% of the sections have not yet exhibited any transverse cracking [see Figure 3-16 (d)]. Similarly, Figure 3-17 presents the extent of transverse cracking by design and site factors. Figure 3-18 shows the variation of transverse cracking within each site of the SPS-1 experiment.

76 30% 35% 40% 45% 50% 55% 4 7 DG AB AT B AT B/ DG AB 8 12 16 ND D Design Factors P e r c e n t o f s e c t i o n s c r a c k e d (a) Extent of occurrence of LC-WP cracking by design factors 30% 40% 50% 60% 70% 80% 90% WF WNF DF DNF F C Site Factors P e r c e n t o f s e c t i o n s c r a c k e d (b) Extent of occurrence of LC-WP cracking by site factors 0 20 40 60 80 100 120 140 -0 0-2 5 25 -50 50 -75 75 -10 0 10 0-1 25 > 1 25 LC-WP, m N u m b e r o f s e c t i o n (c) Frequency of sections for LC-WP cracking 54% 24% 8% 2%1% 3% 8% -0 0-25 25-50 50-75 75-100 100-125 > 125 (d) Distribution of sections for LC-WP cracking Figure 3-10 Occurrence of LC-WP — SPS-1 experiment

77 0 10 20 30 40 50 60 70 4 7 DG AB AT B AT B/ DG AB 8 12 16 ND D Design Factors A v e r a g e L C - W P , m (a) Average LC-WP by design factors 0 10 20 30 40 50 60 70 80 90 WF WNF DF DNF F C Site Factors A v e r a g e L C - W P , m (b) Average LC-WP by site factors Figure 3-11 Extent of LC-WP — SPS-1 experiment State L C - W P ( m ) 555148403935323130262220191210541 250 200 150 100 50 0 118 104 114 102 123 116 104 Figure 3-12 LC-WP by site — SPS-1 experiment

78 50% 55% 60% 65% 70% 75% 4 7 DG AB AT B AT B/ DG AB 8 12 16 ND D Design Factors P e r c e n t o f s e c t i o n s c r a c k e d (a) Extent of occurrence of LC-NWP cracking by design factors 50% 60% 70% 80% 90% 100% WF WNF DF DNF F C Site Factors P e r c e n t o f s e c t i o n s c r a c k e d (b) Extent of occurrence of LC-NWP cracking by site factors 0 10 20 30 40 50 60 70 80 -0 0-2 5 25 -50 50 -75 75 -10 0 10 0-1 25 > 1 25 LC-NWP, m N u m b e r o f s e c t i o n (c) Frequency of sections for LC-NWP cracking 32% 19%6%4% 6% 5% 28% -0 0-25 25-50 50-75 75-100 100-125 > 125 (d) Distribution of sections for LC-NWP cracking Figure 3-13 Occurrence of LC-NWP — SPS-1 experiment

79 1 21 41 61 81 101 121 4 7 DG AB AT B AT B/ DG AB 8 12 16 ND D Design Factors A v e r a g e L C - N W P , m (a) Average LC-NWP by design factors 0 20 40 60 80 100 120 140 160 180 WF WNF DF DNF F C Site Factors A v e r a g e L C - N W P , m (b) Average LC-NWP by site factors Figure 3-14 Extent of LC-NWP — SPS-1 experiment State L C - N W P ( m ) 555148403935323130262220191210541 300 250 200 150 100 50 0 122 119 117 114 Figure 3-15 LC-NWP by site — SPS-1 experiment

80 25% 30% 35% 40% 4 7 DG AB AT B AT B/ DG AB 8 12 16 ND D Design Factors P e r c e n t o f s e c t i o n s c r a c k e d (a) Extent of occurrence of transverse cracking by design factors 0% 10% 20% 30% 40% 50% 60% 70% 80% WF WNF DF DNF F C Site Factors P e r c e n t o f s e c t i o n s c r a c k e d (b) Extent of occurrence of transverse cracking by site factors 0 20 40 60 80 100 120 140 160 -0 0-1 0 10 -20 20 -30 30 -40 40 -50 > 5 0 TC, m N u m b e r o f s e c t i o n (c) Frequency of sections for transverse cracking 65% 20% 9% 1%1% 2% 2% -0 0-10 10-20 20-30 30-40 40-50 > 50 (d) Distribution of sections for transverse cracking Figure 3-16 Occurrence of transverse cracking — SPS-1 experiment

81 0 2 4 6 8 10 12 14 16 18 20 4 7 DG AB AT B AT B/ DG AB 8 12 16 ND D Design Factors A v e r a g e t r a n s v e r s e c r a c k i n g , m (a) Average transverse cracking by design factors 0 5 10 15 20 25 WF WNF DF DNF F C Site Factors A v e r a g e t r a n s v e r s e c r a c k i n g , m (b) Average transverse cracking by site factors Figure 3-17 Extent of transverse cracking — SPS-1 experiment State T C ( m ) 555148403935323130262220191210541 90 80 70 60 50 40 30 20 10 0 121 115 102 121 119105 Figure 3-18 Transverse cracking by site — SPS-1 experiment

82 Rut Depth Figure 3-19 shows the extent of rut depth in all SPS-1 sections by design and site factors. Based on the latest available data (Release 17.0), about 29% of the sections have exhibited less than 5 mm of rut depth whereas about 71% of the sections have shown more than 5 mm rut depth, with 10% of the section showing more than 15 mm of rut depth [see Figure 3-19 (d)]. Figure 3-20 shows the variation of rut depth within each site of SPS-1 experiment. Figure 3-21 shows the age distribution of all the pavement sections for the latest rut depth measurement. Roughness Figure 3-22 shows the extent of change in IRI (∆IRI) for all SPS-1 sections by design and site factors. Based on the latest available data (Release 17.0), about 23% of the sections have exhibited a negligible change in IRI whereas about 77% of the sections have shown some level of change in IRI, with 10% of the section showing ∆IRI more than 0.4 m/km [see Figure 3-19 (d)]. The data is also summarized for the initial IRI (smoothness just after the construction). Figure 3-23 shows the extent of the initial IRI by design and site factors. It can be seen that about 84% of the sections were built with initial IRI of less than 1.0 m/km and about 16% of the sections with initial IRI more than 1.0 m/km [see Figure 3-23 (d)]. Figure 3-24 shows the variation of roughness within each site of the SPS-1 experiment. Figure 3-25 presents the age distribution of all the sections at the latest roughness profile measurement.

83 6 7 8 9 10 4 7 DG AB AT B AT B/ DG AB 8 12 16 ND D Design Factors A v e r a g e R u t D e p t h ( m m ) (a) Average rut depth by design factors 0 2 4 6 8 10 12 WF WNF DF DNF F C Site Factors A v e r a g e R u t D e p t h ( m m ) (b) Average rut depth by site factors 0 10 20 30 40 50 60 70 -5 5-7 7-9 9-11 11-13 13-15 > 15 Rut Depth, mm N u m b e r o f s e c t i o n (c) Frequency of sections for rut depth 29% 25% 20% 7% 4% 5% 10% -5 5-7 7-9 9-11 11-13 13-15 > 15 (d) Distribution of sections for rut depth Figure 3-19 Extent of rut depth — SPS-1 experiment

84 State R u t D e p t h ( m m ) 555148403935323130262220191210541 30 25 20 15 10 5 0 113 115 117 102 119 115 112 102 Figure 3-20 Rut depth by site — SPS-1 experiment 0 10 20 30 40 50 60 70 80 90 -3 3-5 5-7 7-9 9-11 Age (years) N u m b e r o f s e c t i o n (a) Frequency of sections for latest age 3% 12% 38% 31% 16% -3 3-5 5-7 7-9 9-11 (b) Distribution of sections for latest age Figure 3-21 Age distribution of rut depth measurement — SPS-1 experiment

85 0.0 0.1 0.2 0.3 0.4 0.5 4 7 DG AB AT B AT B/ DG AB 8 12 16 ND D Design Factors A v e r a g e I R I ( m / k m ) (a) Average change in IRI by design factors 0.00 0.10 0.20 0.30 0.40 WF WNF DF DNF F C Site Factors A v e r a g e D I R I ( m / k m ) (b) Average change in IRI by site factors 0 10 20 30 40 50 60 70 80 90 -0 0-0.2 0.2-0.4 0.4-0.6 0.6-0.8 0.8-1 > 1 ∆IRI, m/km N u m b e r o f s e c t i o n (c) Frequency of sections for change in IRI 23% 39% 18% 10% 4% 3% 3% -0 0-0.2 0.2-0.4 0.4-0.6 0.6-0.8 0.8-1 > 1 (d) Distribution of sections for change in IRI Figure 3-22 Extent of ∆IRI— SPS-1 experiment

86 0.5 0.6 0.7 0.8 0.9 1.0 4 7 DG AB AT B AT B/ DG AB 8 12 16 ND D Design Factors A v e r a g e I R I o ( m / k m ) (a) Average initial IRI by design factors 0.5 0.6 0.7 0.8 0.9 1.0 WF WNF DF DNF F C Site Factors A v e r a g e I R I o ( m / k m ) (b) Average initial IRI by site factors 0 20 40 60 80 100 120 -0.6 0.6-0.8 0.8-1 1-1.2 1.2-1.4 >1.4 IRIo, m/km N u m b e r o f s e c t i o n (c) Frequency of sections for initial IRI 9% 48% 27% 14% 2% -0.6 0.6-0.8 0.8-1 1-1.2 1.2-1.4 (d) Distribution of sections for initial IRI Figure 3-23 Extent of IRIo— SPS-1 experiment

87 State C h a n g e i n I R I ( m / k m ) 555148403935323130262220191210541 3.0 2.5 2.0 1.5 1.0 0.5 0.0 113 101 107 102 113118 105 102 108 120 119 107 (a) Change in IRI by site State I n i t i a l I R I ( m / k m ) 555148403935323130262220191210541 1.75 1.50 1.25 1.00 0.75 0.50 124 116 108 116 (b) Initial IRI by site Figure 3-24 Roughness by site — SPS-1 experiment 0 20 40 60 80 100 -3 3-5 5-7 7-9 9-11 Age (years) N u m b e r o f s e c t i o n (a) Frequency of sections for latest age 9% 7% 25% 42% 17% -3 3-5 5-7 7-9 9-11 (b) Distribution of sections for latest age Figure 3-25 Age distribution of roughness measurement — SPS-1 experiment

88 3.3.5 Dynamic Load Response Data (DLR) — Flexible Pavements This section of the report summarizes the data availability for the instrumented flexible pavement sections in OH (39). According to Ohio University report [5], eight series of controlled truck tests had been completed on these instrumented pavement sections as shown in Table 3-8. Each series of tests followed a similar pattern with regards to how the tests were setup and conducted. The general steps followed during each test are discussed in reference [5]. Only series II data and part of series IV data are available in DataPave (Release 17.0). Also data pertaining to instrumented SPS-8 sections in Ohio are not available in the database. The testing setup details have been obtained from DLR_TEST_MATRIX table. The locations of strain gauges and LVDTs data were obtained from DLR_STRAIN_CONFIG_AC and DLR_LVDT_CONFIG tables. The depth at which strain gauges were installed is not available in the DataPave; therefore this data was obtained from Ohio University report [5]. The peak strain, deflection and pressure data were extracted from DLR_STRAIN_TRACE_SUM_AC, DLR_LVDT_TRACE_SUM_AC and DLR_PRESSURE_TRACE_SUM_AC tables. Only data collected from these instrumented sections in 1996 and 1997 are available in DataPave. The specifics of the tests during series II (in 1996) are listed in Table 3-9 and Table 3-10. The test dates for which strain data are available in DataPave are shaded in grey. Table 3-11 details the series IV test sequence, which is available in the Release 17.0 version of DataPave.

89 Table 3-8 Controlled vehicle parameters Dynamic Parameters Test Dates Test Series Truck No. Passes Section Monitored Load Speed No. Axles Axle Spacing Tires Veh. Dyn. 12/95 3/96 I CNRC 144 1 X X X X 8/96 II Single Tandem 85 87 6 X X 6/97 III CNRC Tandem 127 122 7 7 X X X X X X X X 7/97 8/97 IV Single Tandem 77 77 12 X X 10/98 V Single Tandem 72 60 8 X X 9/99 10/99 VI Single Tandem 86 86 8 X X 10/99 VII Single Tandem FWD Dynaflect 30-60/sec. 30-60/sec 50 drops/sec. 20 read/sec 7 X X 4/01 5/01 VIII Single Tandem 80 80 10 X X Source: [5] Table 3-9 Series II Truck Parameters – ODOT Single-Axle Dump Truck Date Nominal Load (kips) Rear Axle (kips) Nominal Speed (mph) Load I.D Run No. 8/6/96 18 18.45 30,40,50 C 1-14 8/7/96 18 18.45 30,40,50 C 1-14 8/9/96 22 22.23 30,40,50 C 1-13 Source: [5] Table 3-10 Series II Truck Parameters – ODOT Tandem-Axle Dump Truck Rear Axle Load (kips) Date Nominal Load (kips) Lead Rear Nominal Speed (mph) Load I.D Run No. 8/2/96 32 16.62 16.23 30,40,50 A 1-17 8/3/96 32 16.62 16.23 30,40,50 A 1-15 8/5/96 42 21.14 21.38 30,40 B 1-11 8/6/96 42 21.14 21.38 30,40,50 B 1-16 Source: [5] Table 3-11 Series IV Truck Parameters – ODOT Single-Axle Dump Truck Date Nominal Load (kips) Rear Axle (kips) Nominal Speed (mph) Load I.D Run No. 7/2/97 18 17.35 30,40,50 K 1-20 7/3/97 22 24.95 30,40,50 L 1-18 Source: [5]

90 It was also observed that not all the runs conducted during each test series for a specific date and sections are available in the strain data (see Appendix A3). Furthermore, strain data is not available for all gauges or all speed levels. For example, in section 39-102 data recorded for only 3 strain gauges are available in the database, whereas, the instrumentation plan for this section shows that there are 6 strain gauges located under the asphalt layer. Appendix A3 show the average peak strain values of the data for different offset categories. Data summaries were also prepared for surface deflection data (from LVDT) and pressure data (from pressure cells) within each section, and are attached in Appendix A3. Discrepancies in Dynamic Load Response Data The data availability for dynamic load response for the SPS-1 experiment in the current version of DataPave has highlighted several discrepancies. These deficiencies can seriously affect the usefulness of this data for any type of analysis; some of these shortcomings are highlighted here for future improvements: • Keeping in consideration the amount of data collected for these instrumented sections; only limited data from series II and series IV are currently available (DataPave Release 17.0). • The direction of strain gauges (Longitudinal or transverse) is not available in DataPave. These had to be obtained from the Ohio University report [5]. • Similarly, the depth of strain gauges from the surface is also currently missing from the database. • In order to validate the dynamic load response mechanistically, the material properties for pavement layers have to be calculated at the time of testing. To facilitate this objective, the time of testing and temperature should be included as a part of dynamic load response data. Also it would have been useful to have data from FWD testing conducted at the locations at the strain gauges and pressure cells.

91 3.4 DATA AVAILABILITY IN SPS-2 EXPERIMENT This section of the report is a discussion on data availability for the SPS-2 experiment. DataPave (Release 17, January 2004) was the primary data source for the study. Data from previous releases and other sources were used only to supplement the DataPave (Release 17) data. The construction information for each site was obtained from construction reports, climatic data for WI (55) (not available in Release 17) was obtained from DataPave 3.0, and distress maps were used to determine transverse crack locations. Data that were used for this study can be broadly classified into categories as summarized in Table 3-12. A brief description of each data type and its availability are presented in the subsequent sections. Table 3-12 Data Categories and their description Serial No. Data Type Details 1 Site Information Site Location information, Construction information, Climatic data, Traffic data 2 Materials data Properties of materials of different layers for test sections 3 Pavement Structure data Layer type and thickness information, and information about other design features such as lane width, shoulders and dowels 4 Monitoring data Profile, Distress, Deflection (FWD), and Faulting data 5 Dynamic Load Response (DLR) data Instrumentation and testing information, pavement response data 3.4.1 General Site Information The information that is common to all sections at a test site has been categorized under this heading. Construction Reports Construction reports were prepared for each site by the concerned consultant and department of transportation. These documents describe the construction process from conception to completion. In addition, the reports present information on the pavement geometric layout, construction issues (and deviations, if any), traffic, environmental conditions during construction, and material quality control data. These reports are available for all the sites in the

92 experiment. A summary of construction issues at each of the 14 sites can be found in Appendix B1. Climatic data In the LTPP database, climatic data is available from two sources- Virtual Weather Station (VWS) and Automated Weather Station (AWS). A wide range of variables that define the climate are available. The climatic zones in LTPP are defined based on two parameters: average annual precipitation and average annual freezing index. These two variables were used to confirm the climatic classification of each site. AWS data for DE (10) is not available from Release 17 of DataPave. Data for all other sites are available from AWS. Climatic data from VWS is available for all sites except WI (55), in Release 17. VWS data for this site was obtained from DataPave 3.0. VWS data are available for 17 years for all sites expect CA and WI for which 49 years of data are available. Traffic data The traffic data available in the LTPP database is presented in three forms: Monitored, Estimated and Axle Distribution. Traffic data availability is shown in more detail in Table 3-13. Traffic being one of the most important factors that determine pavement performance, inconsistency in traffic data was compensated, to some extent, by estimating an average annual traffic (called ‘proposed’ traffic) for each of the sites based on all the three sources of traffic data. The ‘proposed’ traffic is used as a covariant in the analyses.

93 Table 3-13 Summary of Traffic data availability KESALs per year State ID Monitored Construction reports Estimated Axle Distribution NCHRP Report 499 Proposed Arizona, AZ (4) 1054 - 1200 1021 1220 1092 Arkansas, AR (5) - 1700 1969 2041 2160 1903 California, CA (6) - 2405 - - - 2405 Colorado, CO (8) 350 454 395 246* 320 400 Delaware, DE (10) - 300 410 - 430 355 Iowa, IA (19) 56* 330 94* 424 70 377 Kansas, KS (20) 732 870 670 1283* 740 757 Michigan, MI (26) 1872 1330 - 1313 1780 1505 Nevada, NV (32) 813 799 492* 499* 790 806 North Carolina, NC (37) 830 - 1499 * 600 1300 715 North Dakota, ND (38) - 419 432 - - 426 Ohio, OH (39) 612 797 - 415 630 608 Washington, WA (53) 462 875* 194* 286* 350 462 Wisconsin, WI (55) - 180 - 122 - 151 Note: * Data considered as an outlier

94 Traffic opening date is the date on which traffic was allowed to pass over the newly constructed test sections. This data is available in the database for all the sites. The age of a section was calculated using this date and the corresponding last survey date. 3.4.2 Materials data Data pertaining to the materials used in the construction of pavement sections have been categorized as Materials data. The data that were used for this study include the material properties of subgrade soil (percent passing #200 sieve) and PCC layer (mix design information, coefficient of thermal expansion, unit weight, etc.), apart from strength testing results of lean concrete and PCC. Subgrade Subgrade soil data in the form of percent passing #200 sieve (available for all sites) were used to classify subgrade soil as either “fine” or “coarse” and compare results with subgrade soil classification data that are available from other sources in DataPave. Lean Concrete The compressive strength data for LCB are available for 96 % of the sections. The 7-day compressive strength was used to compare with the stipulated target strength of 3.5 MPa [4]. Portland Cement Concrete All the details of PCC mix design such as cement content, aggregate content (coarse and fine), water content, and additive type are available for all sites except WI (55). For most of the sites which have data, two types of mixes were used, one for each of the two levels of target 14-day flexural strength. In DE (10) more than two types of mixes were used, and PCC mix design data are available for all the sections. Though not a part of the experiment design, PCC compressive strength, split tensile strength, and modulus of elasticity are also reported in the database. The mechanical properties of concrete were recorded at 7, 14 and 365 days after casting. Compressive strength and split tensile strength data from testing of core samples are also available. Table 3-14 below is a

95 summary of data availability for PCC mechanical properties (except for flexural strength) from DataPave Release 17. Only 52% of the sections in the SPS-2 experiment have 14-day flexural strength data. Data for sections in CA (6) and ND (38) are not available. The 14-day flexural strength data were used for comparison with specified target strengths. Table 3-15 is a summary of flexural strength data availability. Coefficient of thermal expansion (CTE) of PCC is an important requirement for conducting a thermal analysis. CTE data are unavailable in DataPave of Release 17. Data were obtained from Portland Cement Concrete Pavements, FHWA. However, CTE data was available only for 16 sections, which are from 8 different sites within the SPS-2 experiment. Table 3-16 below is a summary of CTE data obtained from FHWA. Figure 3-26 is a plot showing CTE of PCC for as a function of aggregate type.

96 Table 3-14 Summary of data availability (percent of sections) for PCC properties Compressive Strength Tensile Strength Site ID Core Fresh Core Fresh Elastic Modulus 4 83 50 92 50 92 5 0 0 0 0 25 6 25 50 50 0 100 8 92 100 92 100 100 10 50 50 67 25 42 19 83 50 100 50 100 20 0 92 0 83 0 26 42 42 42 42 50 32 92 50 92 50 92 37 0 50 75 0 100 38 25 0 25 0 100 39 92 50 75 42 83 53 92 58 100 58 100 55 0 0 0 0 100 Table 3-15 Summary of availability (percent of sections) PCC flexural strength data % of sections with data Site ID 14-day 28-day 365-day 4 75 75 75 5 58 58 58 6 0 0 0 8 100 100 92 10 50 50 50 19 50 50 50 20 100 100 92 26 42 42 50 32 50 50 50 37 25 33 42 38 0 42 92 39 50 50 50 53 58 58 58 55 58 58 0

97 Table 3-16 CTE data obtained from FHWA Site ID Aggregate Type SHRP ID CTE, in/in/oC 5 - 0215 10.2 5 - 0220 11.3 10 Diorite 0205 11.6 10 Diorite 0208 9.2 10 Diorite 0211 9.5 19 Limestone 0224 9.6 20 Limestone 0207 10 20 Limestone 0208 10.65 32 - 0203 10.9 32 - 0208 13.9 32 - 0209 11.1 37 Granite 0203 8.9 37 Granite 0204 11.9 39 Limestone 0204 10.2 55 - 0222 8.8 55 - 0223 9.8 8 8.5 9 9.5 10 10.5 11 11.5 12 Diorite Limestone Granite Aggregate type C TE , i n/ in /C x 1 0e -6 Figure 3-26 CTE of PCC with different aggregate types

98 3.4.3 Pavement Structure data All data that relates to the structure (cross-section) of the pavement sections have been categorized in this section of the report. The data has been used to compare as- designed thicknesses with as-built thicknesses. Information about layer type and thickness is available for all test sections in the experiment. Information about the size and spacing of dowel bars is available for all the sections except for 4 sections in WA (53). Though not a part of the experiment design, details about the shoulders have been obtained. No information about the shoulders is available for the site WI (55). 3.4.4 Monitoring data All data that are collected during distress surveys and during FWD testing has been categorized as Monitoring data. Longitudinal profile data, distress data, faulting data, and deflection data fall under this category. These data are available for all the sections in the experiment. Table 3-17 is the summary of data availability (from Release 17 of DataPave) in all the classifications of data listed above.

99 Table 3-17 Summary of data availability for SPS-2 experiment Data category Data type Data Availability, % of sections Site information Construction reports Climatic data Virtual Weather Station Annual Temperature Annual Precipitation Automated Weather Station Monthly Temperature Monthly precipitation Traffic data* Traffic Open date Monitored Estimated Axle Distribution data 100 93 93 93 93 100 65 71 78 Materials data Subgrade Sieve analysis Classification Backcalculated moduli Lean Concrete Base Compressive Strength Portland Cement Concrete PCC mix data 14-day Flexural Strength Compressive Strength Split tensile Strength Static modulus of Elasticity CTE + Unit weight 53 100 0 96 100 52 92 91 78 0 63 Pavement structure Layer details Type Representative thickness Dowel bar details Diameter Length Spacing Shoulder information Type Width Thickness 100 100 98 98 98 93 93 93 Monitoring** Profile data (IRI) Distress data Faulting data FWD data Deflection Temperature during testing 100 100 100 100 100 Note: *Monitored, Estimated, or Axle Distribution data is considered to be available for a site even if the data is available only for one year. **Data is said to be available for a section even if it is available for just one year. + CTE data is not available in DataPave. It was obtained from FHWA for this study.

100 A detailed discussion on data availability for each site can be found in Appendix B1. 3.4.5 Design versus Actual Construction Review A brief discussion on construction guidelines was presented in Chapter 2. A review of all the features in the experiment was conducted to identify deviations from design. In this section of the report, a comparison between as-designed and as- constructed features of the experiment is presented. A brief discussion on the construction issues will be followed by a discussion on the deviations, if any, in the design and site features of the experiment. The design versus construction review for each site can be found in Appendix B1. Construction Issues Information regarding construction issues was obtained from the construction reports. A detailed site-specific discussion on construction issues can be found in Appendix B1. Some of the major issues in the SPS-2 experiment are below: • Shrinkage cracks in LCB were observed soon after construction at sites AZ (4), CA (6), DE (10), MI (26), NV (32), NC (37), ND (38), and WA (53). • PCC mixes that were different from what was stipulated were used at DE (10), NV (32) and OH (39) sites, respectively. • Construction delays occurred due to bad weather at sites MI (26) and ND (38). • Improper size dowel bars were used at CA (6) and NC (37) sites. At CA (6) site, 32 mm and 38 mm diameter bars were used in both thinner and thicker slab sections. At the NC (37) site, all the sections were constructed with 38 mm – diameter dowel. • Underground structures were present at sites IA (19) and KS (20) within the monitoring length of the sections. • Repairing (such as Partial depth repairs, full depth repairs, crack sealing, and shoulder restoration) was done to some sections (20-0201, 32-0201, and all the sections at the sites in AR (5) and ND (38) after opening the sections to traffic. A review was done for those factors in the experiment that have corresponding guidelines. The features for which the review was conducted include: 9 Site factors o Subgrade soil type, and o Climatic zone. 9 Design factors o Layer thickness, and o 14-day flexural strength of PCC.

101 Each of the above features will be reviewed individually to identify deviations, if any, from the guidelines. Site Factors Subgrade type: In AR (5), sections 0222 and 0223 were constructed on fine-grained soils while all the other sections were constructed on coarse-grained soils. Similarly, in NV (32), sections 0201 and 0205 were built on coarse-grained soils whereas the other sections were built on fine-grained soils. At the CO (8) site, 5 sections were constructed on coarse-grained soils while the other 7 were constructed on fine-grained soils. Climatic zone: The climatic data (VWS data) were used to categorize sites into 4 climatic zones according to the LTPP definitions for climatic zones. All the SPS-2 sites were appropriately classified. Figure 3-27 is a scatter plot showing all the sites in the experiment and LTPP criteria (reference lines at 508 mm and 83.3 oC-day) regarding climatic zones. 0 200 400 600 800 1000 1200 1400 Avg. Annual Freezing Index, C-day 200 400 600 800 1000 1200 1400 A vg . A nn ua l P re ci pi ta tio n, m m 4 5 6 8 10 19 20 26 32 37 38 39 53 55 Figure 3-27 Scatter plot showing distribution of sites by climate Design Factors Layer Thickness: PCC thickness and DGAB thickness for the test sections were compared with their respective target thicknesses. Results from the comparison are WFWNF DFDNF

102 discussed below. Table 3-18 is a summary of as-designed versus as-constructed comparison for PCC layer and the base layers. The allowable range of thickness does not apply to bases other than DGAB, as the guidelines do not define a range. PCC thickness: The experiment has two levels of PCC thickness- 203 mm and 279 mm. The allowable deviation from the target PCC thickness according to the guidelines is 6.4 mm. Among sections with target thickness of 203 mm, only 28 sections (33 %) conform to the allowable deviation of 6.4 mm. The remainder of the sections (67%) were built either thicker or thinner by more than 6.4 mm. Figure 3-28 is the cumulative frequency graph of PCC thickness. 0 5 10 15 20 25 30 35 40 <=180 180-197 197-209 209-220 220-240 240-260 Thickness range, mm N o. o f s ec tio ns 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Pe rc en t s ec tio ns b el ow No. of sections Percent sections below Figure 3-28 Cumulative frequency plot for actual thickness of sections with target thickness of 203 mm Among sections with a target thickness of 279 mm, 44 sections (53 %) conform to the allowable deviation of 6.4 mm. Figure 3-29 is the cumulative frequency graph showing the percent of sections and number of sections below the corresponding thickness values. Base thickness: Though there are no guidelines limiting deviation from design thickness for LCB and PATB, the allowable deviation from target elevation for DGAB is 12.7 mm. Figure 3-30 is a cumulative frequency distribution of actual base thickness of DGAB sections (target thickness of 152.4 mm). 80% of the sections built on DGAB have thickness that falls within the allowable range (see Table 3-18), as defined by the guidelines.

103 0 5 10 15 20 25 30 35 40 45 50 <273 273-285 285-300 300-315 Thickness range, in. N o. o f s ec tio ns 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Pe rc en t s ec tio ns b el ow No. of sections Percent sections below Figure 3-29 Cumulative frequency plot for actual thickness of sections with target thickness of 279 mm 0 5 10 15 20 25 30 35 40 45 <=140 140-165 165-190 190-215 215-240 240-260 Base thickness, mm N o. o f s ec tio ns 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Pe rc en t s ec tio ns b el ow Percent sections below No. of sections Figure 3-30 Cumulative frequency plot for actual base thickness of sections on DGAB Table 3-18 Summary of deviation in thickness from design Layer Type Target Thickness, mm Count, no. of sections Mean, mm Standard Deviation, mm Coefficient of Variance, % Below allowable range, % sections Within allowable range, % sections Above allowable range, % sections 203 84 212 12 5 7 33 60 PCC 279 83 286 9 3 4 53 43 DGAB 152 56 163 34 21 4 80 16 LCB 152 56 160 10 6 - - - PATB 102 55 101 14 14 - - - DGAB below PATB 102 55 114 36 32 - - -

104 PCC Flexural Strength: At each site, 6 sections have a target 14-day flexural strength of 3.8 MPa and the other 6 sections have target 14-day flexural strength of 6.2 MPa. Comparisons between the actual flexural strengths and target 14-day strength were made. Figure 3-31 through Figure 3-36 are cumulative histograms for flexural strength at 14, 28 and 365 days. It is evident from the plots that at 365 days most of the sections that failed to reach the target at 14 days have reached their target strengths. Among the sections with target PCC 14-day flexural strength of 3.8 MPa, 7 sections, of the 44 sections for which data are available, failed to meet the criterion of 3.4 MPa at 14-days. At 28-days just 1 of the sections failed to meet the criterion and at 365 days all the sections have met the criterion. Among sections with target 14-day PCC flexural strength of 6.2 MPa flexural strength data are available for 42 sections. Of these sections, 16 sections failed to meet the target of 5.6 MPa at 14-days. Eight sections met the criterion at 28 days and 5 more met the criterion of 5.4 MPa at 365 days. Other features Dowel diameter: It was stipulated in the guidelines that all the sections with 203 mm target PCC slab thickness have 32 mm diameter dowels while the sections with 279 mm have 38 mm diameter dowels. Improper size dowel bars were used at CA and NC sites. At CA site, 32 mm and 38 mm diameter bars were used in both thinner and thicker slab sections. At the NC site, all the sections were constructed with dowels of diameter 38 mm. At all other sites no deviation was observed.

105 0 2 4 6 8 10 12 14 <2 .8 2. 8- 3. 1 3. 1- 3. 4 3. 4- 3. 8 3. 8- 4. 1 4. 1- 4. 5 4. 5- 4. 8 4. 8- 5. 2 5. 2- 5. 5 14-day Flexural strength, psi N um be r o f s ec tio ns 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Pe rc en t o f s ec tio ns Number of sections Percent sections below Figure 3-31 Cumulative frequency graph for 14-day flexural strength of sections with target strength of 3.8 MPa 0 2 4 6 8 10 12 14 2. 8- 3. 1 3. 1- 3. 4 3. 4- 3. 8 3. 8- 4. 1 4. 1- 4. 5 4. 5- 4. 8 4. 8- 5. 2 5. 2- 5. 5 5. 5- 5. 9 5. 9- 6. 2 6. 2- 6. 6 28-day Flexural strength, psi N um be r o f s ec tio ns 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Pe rc en t o f s ec tio ns Number of sections Percent sections below Figure 3-32 Cumulative frequency graph for 28-day flexural strength of sections with target strength of 3.8 MPa 0 2 4 6 8 10 12 14 3. 4- 3. 8 3. 8- 4. 1 4. 1- 4. 5 4. 5- 4. 8 4. 8- 5. 2 5. 2- 5. 5 5. 5- 5. 9 5. 9- 6. 2 6. 2- 6. 6 6. 6- 6. 9 365-day Flexural strength, psi N um be r o f s ec tio ns 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Pe rc en t o f s ec tio ns Number of sections Percent sections below Figure 3-33 Cumulative frequency graph for 365-day flexural strength of sections with target strength of 3.8 MPa

106 0 2 4 6 8 10 12 14 <2 .8 2. 8- 3. 1 3. 1- 3. 4 3. 4- 3. 8 3. 8- 4. 1 4. 1- 4. 5 4. 5- 4. 8 4. 8- 5. 2 5. 2- 5. 5 5. 5- 5. 9 5. 9- 6. 2 6. 2- 6. 6 6. 6- 6. 9 14-day Flexural Strength, psi N um be r o f s ec tio ns 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Pe rc en t o f s ec tio ns Number of sections Percent sections below Figure 3-34 Cumulative frequency graph for 14-day flexural strength of sections with target strength of 6.2 MPa 0 2 4 6 8 10 12 14 4. 1- 4. 5 4. 5- 4. 9 4. 8- 5. 2 5. 2- 5. 6 5. 5- 5. 9 5. 9- 6. 2 6. 2- 6. 6 6. 6- 7. 0 7. 0- 7. 3 7. 3- 7. 7 7. 7- 8. 0 365-day Flexural Strength range, psi N um be r o f s ec tio ns 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Pe rc en t o f s ec tio ns Number of sections Percent sections below Figure 3-35 Cumulative Frequency graph for 28-day flexural strength of sections with target strength of 6.2 MPa 0 2 4 6 8 10 12 14 3. 5- 3. 8 3. 8- 4. 2 4. 2- 4. 5 4. 5- 4. 9 4. 9- 5. 2 5. 2- 5. 6 5. 6- 5. 9 5. 9- 6. 3 6. 3- 6. 6 6. 6- 7. 0 7. 0- 7. 3 7. 3- 7. 7 7. 7- 8. 0 28-day Flexural Strength range, psi N um be r o f s ec tio ns 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Pe rc en t o f s ec tio ns Number of sections Percent sections below Figure 3-36 Cumulative frequency graph for 365-day flexural strength of sections with target strength of 6.2 MPa

107 3.4.6 Extent and Occurrence of Distresses This section of the report is a discussion on the extent of selected distresses that have occurred in the test sections of the experiment. The pavement performance measures considered include, a. Transverse cracking (number of cracks and percentage of slabs cracked), b. Longitudinal cracking (total length, m), c. Wheelpath joint faulting (mm), and d. Roughness (IRI, m/ km). The list of distresses considered for analyses was determined in agreement with the NCHRP panel for this study. The extent of occurrence (% sections that have shown the distress), and the frequency distribution will be presented for each type of distress based on the latest data available. The extent of occurrence of distresses was studied, as it has a bearing on the selection of the type of analysis procedures to be employed for analysis of the data. Though the analyses procedures help derive conclusions from the data it is imperative that the extent of occurrence of distresses be considered along with the conclusions. Transverse Cracking As per the latest data, 26% of the sections (excluding the site in NV) have exhibited transverse cracks. Figure 3-37 and Figure 3-38 show the magnitude and extent of cracking in the SPS-2 sections. Figure 3-39 and Figure 3-40 show the distribution of transverse cracking as a function of design and site factors. The site-wise occurrence of transverse cracking in the SPS-2 test sections is shown in Figure 3-41. It is evident from the plot that the sections in Nevada, NV (32) have distinctly higher cracking than sections in any of the other sites.

108 0 20 40 60 80 100 120 0 0-25 25-50 50-100 Percent slabs cracked N u m b e r o f s e c t i o n s Figure 3-37 Frequency distribution of percent slab cracked 73% 18% 8%1% 0 0-25 25-50 50-100 Figure 3-38 Distribution of transverse cracking by percent slabs cracked 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50% DF DNF WF WNF C F Site factor levels P e r c e n t o f s e c t i o n s c r a c k e d Figure 3-39 Occurrence of transverse cracking by site factor 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50% D G A B L C B P A T B 8 1 1 D N D 5 5 0 9 0 0 1 2 1 4 Design factor levels P e r c e n t o f s e c t i o n s c r a c k e d Figure 3-40 Occurrence of transverse cracking by design factor

109 4 5 6 8 10 19 20 26 32 37 38 39 53 55 State ID 0 50 100 150 200 250 N um be r o f t ra ns ve rs e cr ac ks 0213 0205 0205 02060205 0218 0222 0218 0218 0217 0202 0201 0217 0218 0217 0201 0205 Figure 3-41 Site-wise occurrence of transverse cracking for SPS-2 test sections Longitudinal Cracking The extent of occurrence of longitudinal cracking is shown in Figure 3-45 and Figure 3-46. As per the latest data from Release 17, 28% of sections exhibited longitudinal cracking. 7% of the sections have the total length of longitudinal cracking of at least 20 m. Figure 3-47 and Figure 3-48 show the distribution of longitudinal cracking by site and design factors. Like in the case of transverse cracking, the sections at the Nevada site have exhibited notably higher magnitude of distresses compared to sections in other sites.

110 4 5 6 8 10 19 20 26 32 37 38 39 53 55 State ID 0 20 40 60 80 100 N um be r of L on gi tu di na l c ra ck s 0206 0206 02060209 0218 0213 0217 0213 0217 0205 0208 0201 0217 0218 0217 0218 0205 Figure 3-42 Site-wise occurrence of longitudinal cracking in SPS-2 test sections Wheel path Joint faulting The site-wise occurrence of faulting in the test sections is shown as box plots in Figure 3-43. It is evident from the plot that less than 5 joints per section have faulting greater than 1.0 mm, in a vast majority of the sections. The extent of occurrence of wheel path joint faulting is given in Figure 3-49 and Figure 3-50. Figure 3-51 and Figure 3-52 show the distribution of faulting by site factors and design factors. Roughness (IRI) The site-wise status of current roughness in the test sections is shown as box plots in Figure 3-44. It is evident from the plot that in most of the sections the current roughness is less than 1.8 m/km. The status of roughness in the test sections is given in Figures 3-53 and 3-54. Figure 3-55 and Figure 3-56 show the distribution of roughness by site factors and design factors.

111 4 5 6 8 10 19 20 26 32 37 38 39 53 55 State ID 0 10 20 30 40 N o. o f j oi nt s w ith fa ul tin g > 1. 0 m m 208 222 Figure 3-43 Site-wise occurrence of faulting in SPS-2 test sections 4 5 6 8 10 19 20 26 32 37 38 39 55 State ID 1.00 2.00 3.00 4.00 C ur re nt R ou gh ne ss (I R I) , m /k m 0206 0201 Figure 3-44 Site-wise occurrence of final roughness values for SPS-2 test sections

112 0 20 40 60 80 100 120 0-25 25-50 >50 Total length of longitudinal cracking N u m b e r o f s e c t i o n s Figure 3-45 Distribution of longitudinal cracking 73% 22%5% 0-25 25-50 >50 Figure 3-46 Distribution of longitudinal cracking 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% DF DNF WF WNF C F Site factor levels P e r c e n t o f s e c t i o n s c r a c k e d Figure 3-47 Extent of longitudinal cracking by site factors 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50% D G A B L C B P A T B 8 1 1 D N D 5 5 0 9 0 0 1 2 1 4 Design factor levels P e r c e n t o f s e c t i o n s c r a c k e d Figure 3-48 Extent of longitudinal cracking by design factors

113 0 20 40 60 80 100 120 0 20 40 60 80 100 Percent of joints faulted >=2.0 mm N u m b e r o f s e c t i o n s Figure 3-49 Distribution of percent joints faulted >=2.0 mm 0% 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% DF DNF WF WNF C F Site factor levels P e r c e n t o f j o i n t s Figure 3-50 Extent of faulting >=2.0 mm in site factors 62% 33% 1%4% 0 0-20 20-40 >40 Figure 3-51 Percent of joints that faulted >= 2.0 mm 0% 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% D G A B L C B P A T B 8 1 1 D N D 5 5 0 9 0 0 Design factor levels P e r c e n t o f j o i n t s Figure 3-52 Extent of faulting >=2.0 mm in design factors

114 0 10 20 30 40 50 60 70 80 90 <1 1-1.5 1.5-2 2-2.5 >2.5 Roughness, m/ km N u m b e r o f s e c t i o n s Figure 3-53 Distribution of roughness, m/ km 6% 50% 38% 3%3% <1 1-1.5 1.5-2 2-2.5 >2.5 Figure 3-54 Distribution of roughness, IRI/ km 1.25 1.35 1.45 1.55 1.65 1.75 DF DNF WF WNF C F Site factor levels A v e r a g e r o u g h n e s s , m / k m Figure 3-55 Extent of roughness in site factors 1.25 1.35 1.45 1.55 1.65 1.75 D G A B L C B P A T B 8 1 1 D N D 5 5 0 9 0 0 1 2 1 4 Design factor levels A v e r a g e r o u g h n e s s , m / k m Figure 3-56 Extent of roughness in design factors

115 3.4.7 Dynamic Load Response Data (DLR) — Rigid Pavements This section of the report summarizes the extent of data available in Release 17 for the DLR experiment. Ohio DLR Experiment Five series of tests were conducted on the sections. Only data from test series II and IV conducted in 1996 and 1997 are available. The specifics of these tests are summarized in Appendix B3. North Carolina DLR Experiment The NC DLR data is available for testing conducted in the years 1994 through 1997. For each section data are available for testing series ‘a’ through ‘h’. Appendix B3 summaries of testing details on the instrumented sections of NC DLR experiment, from the available data. The number of runs for which data are available is also given in Appendix B3.

116 3.5 DATA AVAILABILITY IN SPS-8 EXPERIMENT – FLEXIBLE PAVEMENTS This section of the report summarizes the data availability for flexible pavement sections in the SPS-8 experiment. The availability of all relevant data elements is summarized in Table 3-19. The table shows that availability of the main factors is high, while that of the exogenous factors is somewhat lower. In particular, the availability of traffic data is low; however, the impact of traffic data may be insignificant for the SPS-8 experiment if all the sites have very limited traffic. The availability of the relevant data elements in SPS-8 experiment is discussed in the following sections of the report. 3.5.1 General Site Information Each site has unique characteristics, which can be mainly explained by the particular climatic and soil conditions at a particular location. The SPS-8 experiment mainly focuses on pavement performance based on the environmental aspects of sites in combination with different subgrade types. The particular site information can be further divided into construction, climate and traffic. Construction Issues The construction reports prepared by the supervisory consultants for each site were reviewed to identify the deviations/problems during the construction of each site. These deviations might be helpful in explaining the unusual trends in performances (premature failures) at a particular site. The summary of deviations has been prepared for all 15 sites in the SPS-8 experiment and is given in Appendix C.

117 Table 3-19 Summary of SPS-8 data element availability –Flexible pavements Data Category Data Type Data Availability, % Site Information Construction Reports Climatic data Virtual Weather Station Annual Temperature Annual Precipitation Automatic Weather Station Monthly Temperature Monthly Precipitation Traffic data Traffic Open date Estimated ESALs Monitored ESALs Axle Load Spectrum 93 93 93 47 47 93 60 33 33 Material Data Asphalt Layer Core Examination Bulk Specific Gravity Max Specific Gravity Asphalt Content Asphalt Resilient Modulus Penetration Viscosity Asphalt Specific Gravity Aggregate Gradation Fine Aggregate Particle Shape Layer Thickness Unbound Base Gradation Subgrade Subgrade Gradation Atterberg Limits Subgrade Modulus 80 75 78 78 19 69 65 69 81 21 100 78 78 84 44 Pavement Structure Layer details Type Representative thicknesses Constructed thicknesses Shoulder information Type Width Thickness 100 100 100 93 93 93 Monitoring** FWD data Deflections Temperature at Testing Backcalculated Moduli Manual Distresses data Longitudinal Profile (IRI) Transverse Profile (Rut Depth) 100 100 13 100 100 100 Note: ** Data is said to be available for a section even if it is available from only one survey.

118 Climatic Data As explained before for the SPS-1 experiment, the average annual rainfall and average annual freezing index were used to classify each site into four climatic regions. The classification definitions for each zone were taken from the LTPP DataPave. The summary of the climatic data from the VWS for all sites in SPS-8 is given in Table 3-20. Only climatic data for CA (6) is not available in Release 17.0 of DataPave. Traffic data The SPS-8 experiment design stipulates that traffic volume in the study lane be at least 100 vehicles per day but not more than 10,000 ESAL per year. Therefore, it is important to check the traffic not exceeding the threshold specified for this experiment. The traffic data is only available for 8 out of 15 sites from estimate and monitoring modules of DataPave (Release 17.0). No traffic data is available for AR (5), CA (6), MO (29), NJ (34), NM (35), NC (37) and WI (55). 3.5.2 Material Data The material properties of all the layers in a pavement system play a very significant role in its future performance. The SPS-8 Experiment was designed to study the specific effects of a range of environments on the pavement performance; therefore the material properties which are susceptible to climatic changes need to be investigated. In this experiment the subgrade type was a factor (fine or coarse), while the asphalt mix and base material properties were assumed to be uniform across all states. The subgrade material properties were investigated. The summary of soil gradation and Atterberg limit information required for classification is given in Table 3-21.

119 Table 3-20 Summary of Environmental data of the sections in SPS-8 State Climatic Zone AATP1 (mm) AIPD2 (days) WDPY3 (days) Avg. Days Above 32 oC Avg. Days below 0 oC AAT4 (oC) FI (deg days) FT (cycles) 050800 WNF 1374 34 133 64 52 17 46 48 080800 DF 372 7 95 31 162 10 326 142 280800 WNF 1427 37 145 52 65 16 57 60 290800 WF 1079 27 144 37 105 13 167 92 29A800 WF 945 22 137 29 112 12 334 84 300800 DF 371 4 132 4 198 6 574 163 340800 WF 1071 27 119 8 68 13 127 56 350800 DNF 346 5 92 83 99 15 9 100 360800 WF 891 17 193 5 130 9 437 87 370800 WNF 1342 33 151 36 46 17 14 47 390800 WF 972 24 153 10 130 10 374 96 460800 DF 423 8 96 25 175 7 978 107 480800 WNF 1015 24 131 99 19 20 10 18 48A800 WNF 846 22 100 94 35 19 21 34 490800 DF 473 7 118 8 198 7 498 170 530800 WF 510 7 137 30 91 11 169 73 53A800 WF 386 3 135 33 88 11 163 71 550800 WF 814 17 151 4 175 6 1015 96 Note: 1-Average Annual Total Precipitation (mm), 2-Average Intense Precipitation Days in a year, 4-Wet Days per Year, 4-Average Annual Temperature

120 Table 3-21 Subgrade soil properties for SPS-8 flexible pavements State SHRP ID -# 200 HYDRO_02 HYDRO_002 HYDRO_001 COARSE_SAND FINE_SAND SILT CLAY COLLOIDS LL PL PI Expansive SG Zone Frost 5 0803 77 34 16 - 0 24 60 16 - 29 17 12 N F WNF Y 5 0804 58 34 18 - 3 30 40 18 - 34 15 10 N F WNF Y 6 A805 11 5 2 - 28 61 9 2 - - - 0 N C DNF N 6 A806 14 5 2 - 29 57 12 2 - - - 0 N C DNF N 29 0801 63 49 25 22 0 10 38 25 22 44 19 26 Y F WF Y 29 0802 59 57 43 37 2 6 22 43 37 68 26 42 Y F WF Y 29 A801 92 77 41 38 2 2 36 41 38 57 22 35 Y F WF Y 29 A802 87 70 36 30 3 3 35 36 30 58 19 40 Y F WF Y 30 0805 9 6 2 66 11 6 2 - - - 0 N C DF N 30 0806 8 6 2 - 14 11 6 2 - - - 0 N C DF N 34 0801 8 3 1 - 16 67 7 1 - - - - N C WF N 34 0802 7 4 1 - 19 67 7 1 - - - - N C WF N 36 0801 27 13 7 7 5 54 21 7 7 8 5 2 N C WF N 36 0802 6 6 4 - 32 57 3 4 - 0 0 0 N C WF N 37 0801 8 7 2 - 6 84 8 2 - - - 0 N C WNF N 37 0802 12 8 4 - 12 76 8 4 - - - 0 N C WNF N 39 0804 71 55 28 - 8 15 43 28 - 30 17 13 N F WF Y 46 0803 27 16 12 1 64 20 4 12 36 19 17 N F DF Y 46 0804 35 30 19 10 26 28 35 4 17 39 18 21 Y F DF Y 48 0801 54 17 10 7 23 38 40 10 - 16 9 7 N F WNF N 48 0802 51 23 12 - 7 39 33 12 - 29 23 6 N F WNF N 49 0803 35 19 10 - 9 15 22 10 - 29 15 14 N C DF N 49 0804 34 21 10 - 7 12 23 10 - 37 18 19 Y C DF N 53 0801 61 29 9 - 8 8 53 9 - 31 25 6 N F WF N 53 0802 42 21 5 - 8 7 37 5 - - - 0 N C WF N 55 0805 12 7 3 - 20 28 8 3 - - - 0 N C WF N 55 0806 14 9 4 - 26 29 11 4 - - - 0 N C WF N Note: Colloidal Content >15% & PI>18, for expansive soils this criterion was adopted (source: Holtz (1959) and U.S.B.R (1974)) Silt, coarse clay having more than 15% material finer than 0.02 mm to be dangerous for frost heave (Source: Holtz & Kovacs, 1981)

121 In addition, two critical aspects of soil behavior were further investigated from the available soil data: expansion of clayey soils in dry zones and frost susceptibility in freeze zones. The active soils were identified by using the following criteria [6]: • Expansive Soils─ colloidal content >15% and PI>18 • Frost Susceptible Soils─ silt, coarse clay having > 15% material finer than 0.02 mm. By using the above criteria, the subgrade soils in States 29 (Missouri), 46 (South Dakota, section 0804) and 49 (Utah, section 0804) were classified as active (expansive) soils, while sections in States 5 (Arkansas), 29 (Missouri), 39 (Ohio, section 0804) and 46 (South Dakota) were identified as having subgrade soils with frost heave potential. 3.5.3 Design versus Actual Construction Review According to the original experiment design as discussed in chapter 2, 12 sites were essential required with two different structural designs. These sites were selected based on the geographical location so that they may be located in different climatic regions. However, due to site specific climatic data the region identified at the design stage may be different. Similarly, the target layer thickness may have variability due to construction. The specific as-constructed site conditions are discussed in the section below. Construction Issues The construction guidelines for SPS-8 sections were discussed in chapter 2. The construction deviations for each site were taken from the construction reports and are summarized in Appendix C. Site Factors The SPS-8 flexible experiment design required that two different structural designs should be repeated in at least 12 sites. However, the actual data on the site factors (climate and subgrade) showed that there are 15 sites in the SPS-8 flexible experiment and currently these are distributed according to Table 2-8. There are 7 sites in WF, and 3 sites each for WNF, DF and DNF zones, respectively. Almost half of the sites were constructed on coarse subgrade, and the others were built on fine subgrade soil.

122 Design Factors The design or structural features which are considered to be the main experimental factors in SPS-8 flexible pavement experiment include: • AC Thickness [4-inch (102 mm) versus 7-inches (178 mm)] • Granular Base Thickness [(8-inch (203 mm) versus 12-inch (305 mm)] The summary of the as-constructed and target thicknesses for all flexible pavements is given in Table 3-22. 3.5.4 Extent and Occurrence of Distress The age of the section is a very important factor in the SPS-8 experiment, as a higher age of a particular section will translate in higher environment related distresses. Figure 3-57 shows the latest age for all flexible pavement sections in SPS-8. Further age distribution of flexible pavements among the SPS-8 sections is shown in Figure 3-58. The age data for SPS-8 sections shows that most of these sections are aged below seven years and are in the early stage on the performance curve. The distress data for the SPS-8 sections was obtained from the files MON_DIS_AC_REV (cracking and non-load related distresses data), MON_T_PROF_INDEX_SECTION (rutting data) and MON_PROFILE_MASTER (roughness). Figure 3-59 and Figure 3-60 show the occurrence and distribution of distresses in the SPS-8 Experiment flexible pavements. The available distress data in Data Pave (Release 17) has only shown five types of distresses in all SPS-8 flexible pavements. Figure 3-60 (a) shows the distribution of rutting in SPS-8 flexible pavement sections. It can be observed that only 9% of the sections have shown more than 5 mm of rutting, where as in the majority of the sections (60%) rutting ranges from 3 to 5 mm. A low amount of rutting is expected in the SPS-8 pavements since load is the major cause of rutting in flexible pavements. Figure 3-60 (b) shows the distribution of roughness data (IRI) based on its magnitude. The data suggests that the majority of sections did not exhibit high levels of roughness, with only 9% of the population with IRI greater than 2 m/km.

123 Table 3-22 Construction details of the flexible pavement sections in SPS-8 State SHRP_ID Subgrade Type AC GB GS 1 SS2 TS Target AC Target GB 5 0803 F 3.8 7.3 4 8 5 0804 F 7.2 12.7 7 12 6 A805 C 4.2 8.2 4 8 6 A806 C 6.6 12.2 7 12 28 0805 C 4 9 4 8 28 0806 F 7 12 7 12 29 0801 F 4.9 7.8 4 8 29 0802 F 7.5 11.5 7 12 29 A801 F 4.3 8.3 4 8 29 A802 F 6.9 12.3 7 12 30 0805 C 4.5 7.1 4 8 30 0806 C 6.9 11.8 7 12 34 0801 C 3.5 7.8 4 8 34 0802 C 6.8 11.6 7 12 35 0801 F 4.4 9.7 4 8 35 0802 F 7.3 12.6 7 12 36 0801 C 4.9 8.4 168 4 8 36 0802 C 7.6 10 156 7 12 37 0801 C 4 8.7 4 8 37 0802 C 7 11.5 7 12 39 0803 F 3.9 7.9 36 4 8 39 0804 F 6.6 11.9 30 7 12 46 0803 F 4.8 8 4 8 46 0804 F 7.2 12 7 12 48 0801 F 4 8.5 10 4 8 48 0802 F 5.5 10.7 10 7 12 49 0803 C 4.9 7.8 41.2 4 8 49 0804 C 6.9 12 41.2 7 12 53 0801 F 3.7 8 38.4 4 8 53 0802 C 6.8 11.7 38.4 7 12 55 0805 C 4.4 8 4 8 55 0806 C 7 12 7 12 Note: 1-Granular subbase, 2-SS represents subgrade layer, the thickness in this column is the fill

124 0 1 2 3 4 5 6 7 8 9 10 5- 08 03 5- 08 04 6- A 80 5 6- A 80 6 28 -0 80 5 28 -0 80 6 29 -0 80 1 29 -0 80 2 29 -A 80 1 29 -A 80 2 30 -0 80 5 30 -0 80 6 34 -0 80 1 34 -0 80 2 35 -0 80 1 35 -0 80 2 36 -0 80 1 36 -0 80 2 37 -0 80 1 37 -0 80 2 39 -0 80 3 39 -0 80 4 46 -0 80 3 46 -0 80 4 48 -0 80 1 48 -0 80 2 49 -0 80 3 49 -0 80 4 53 -0 80 1 53 -0 80 2 55 -0 80 5 55 -0 80 6 Section ID A ge (y ea rs ) Figure 3-57 Age of the flexible pavements in SPS-8 0 2 4 6 8 10 12 14 <2 2-5 5-7 7-9 >9 Age (years) N o. o f s ec tio ns (a) Frequency of age 6% 37% 38% 16% 3% <2 2-5 5-7 7-9 >9 (b) Distribution of age Figure 3-58 Age distribution in the SPS-8 sites ─ flexible pavements

125 31% 69% Alligator Cracking No distress 38% 62% Long. Cracking (WP) No distress 53% 47% Long. Cracking (NWP) No distress 22% 78% Transverse Cracking No distress 22% 78% Ravelling No distress Figure 3-59 Distribution of distresses in SPS-8 flexible pavements sections 3% 28% 60% 9% -1 1-3 3-5 5- (a) Average Rut (mm) 38% 53% 3% 6% -1 1-2 2-3 3-4 (b) Average IRI (m/km) Figure 3-60 Distribution of IRI and Rutting in SPS-8 flexible pavements

126 3.6 DATA AVAILABILITY FOR SPS-8 EXPERIMENT– RIGID PAVEMENTS This section of the report describes data availability for rigid pavement sections in the SPS-8 experiment. All the data types are summarized in Table 3-28; these are similar to the ones described for SPS-2 experiment. 3.6.1 General Site Information Construction Reports Like in the case of SPS-2 sites, the construction reports contain information about the construction process, geometric layout, construction issues, etc. Construction reports are available for all the six sites in the SPS-8 experiment. A summary of the site-specific information can be found in Appendix C. Climate Data The data on climate at the SPS-8 sites is available from AWS and not from VWS as in the case of SPS-2 sections. This information was used to calculate average annual temperature and precipitation at the sites. Then the classification of the sites was confirmed with the derived data. Traffic Data Table 3-29 is a summary of the traffic data available for the rigid pavement sections in SPS- 8 experiment. It is evident form the data that, the traffic on the sections in Ohio (39) is higher than the stipulated upper limit, which is 10,000 ESAL. Traffic data are also available from the construction reports of the sites. A summary of traffic data obtained from construction reports is Table 3-25. It is evident that the AADT for sections in AR (5), MO (29), and WA (53) is below the lower limit of 100 vehicles/day. 3.6.2 Design versus Actual Construction Review Figure 3-61 and Figure 3-62 show the PCC slab thickness deviations for the two thickness levels. Similarly, Figure 3-64 shows the deviations in the base layer thickness. With the exception of the sections in the sites in Texas (48) and Washington (53), all the other sections are in compliance with the stipulated base thickness.

127 Table 3-23 Summary of data availability for SPS-8 experiment –Rigid pavements Data category Data type Data Availability, % of sections Site location information Construction reports Climatic data Virtual Weather Station Annual Temperature Annual Precipitation Automated Weather Station Monthly Temperature Monthly precipitation Traffic data* Traffic Open date Monitored Estimated Axle Distribution 100 0 0 7 7 0 14 14 0 Materials data Subgrade Sieve analysis Atterberg Limits Classification Lean Concrete Base Compressive Strength Portland Cement Concrete PCC mix data Flexural Strength Compressive Strength Split tensile Strength Static modulus of Elasticity CTE 100 100 100 0 100 71 86 86 86 0 Pavement structure Layer details Type Representative thickness Dowel bar details Diameter Length Spacing Shoulder information Type Width Thickness 100 100 0 0 0 100 100 100 Monitoring** Profile data (IRI) Distress data Faulting data 100 100 100 *Monitored, Estimated, or Axle Distribution data is considered to be available for a site even if the data is available only for one year. **Data is said to be available for a section even if it is available for just one year.

128 Table 3-24 Summary of available traffic data Site ID SHRP ID Year Traffic (ESAL) 8 0811 1997 1000 (Estimated) 8 0811 1998 1000 (Estimated) 8 0811 1999 1000 (Estimated) 8 0812 1997 1000 (Estimated) 8 0812 1998 1000 (Estimated) 8 0812 1999 1000 (Estimated) 39 0809 1997 66824 (Monitored) 39 0810 1997 69317 (Monitored) Table 3-25 Summary of traffic data available from the construction reports Site ID 2-way AADT used to calculate design traffic, vehicles/ day Design ESAL, KESAL/ yr 5 38 Not Available 8 2500 12.95 290800 50 96.5 29A800 118 Not Available 39 500 Not Available 48 Not Available 2.15 53 60 182.5 0 50 100 150 200 250 5-0809 8-0811 29-0807 29-A807 39-0809 48-A807 53-A809 Section ID PC C sl ab th ic kn es s, m m Figure 3-61Thickness deviations in sections with target PCC thickness of 203 mm

129 240 250 260 270 280 290 300 310 320 5-0810 8-0812 29-0808 29-A808 39-0810 48-A808 53-A810 Section ID PC C sl ab th ic kn es s, m m Figure 3-62 Thickness deviations in sections with target PCC thickness of 279 mm 0 50 100 150 200 250 5-0809 5-0810 8-0811 8-0812 29- 0807 29- 0808 29- A807 29- A808 39- 0809 39- 0810 48- A807 48- A808 53- A809 53- A810 Section ID Ba se th ic kn es s, m m Figure 3-63 Deviation from target base thickness of 152 mm

130 The experiment design stipulates that the target 14-day flexural strength of the PCC slab concrete be 3.8 MPa (550 psi). Figure 3-64 gives a summary of concrete test data for each section. It can be noted from the table that all the sections for which data are available have concrete of sufficient average 14-day flexural strength as stipulated in the experiment design. 3.6.3 Distress Occurrence The distresses in SPS-8 sections as of Release 17 have been summarized in

131 Table 3-26. Faulting of joints occurred in all the sections except the ones at the Washington site. In 12 of the 14 sections in the experiment, less than 40% of the joints have measurable faulting. In half of the sections, 3 to 20% of the joints faulted more than 1.0 mm. Figure 3-65 shows the distribution of IRI in SPS-8 sections. 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 5-0809 5-0810 8-0811 8-0812 39-0809 39-0810 48-A807 48-A808 53-A809 53-A810 Section ID A ve ra ge 1 4- da y fle xu ra l s tr en gt h, p s Figure 3-64 Average 14-day flexural strength of PCC

132 Table 3-26 Distresses in SPS-8 sections Site ID SHRP ID Trans. Cracks Long. Cracks Corner Breaks Long. Spalling Length Trans. Spalling Trans. Spall Length Scaling No. 5 809 0 0 0 46.2 0 0 0 5 810 0 0 0 37.5 0 0 0 8 811 5 7.7 1 0 2 0.8 1 8 812 0 0 0 0 0 0 0 29 807 3 0.5 0 37.4 1 0.5 0 29 808 0 0 0 4.5 0 0 0 29 A807 0 0 0 0 0 0 0 29 A808 0 0 0 0 0 0 0 39 809 1 0 0 0.7 0 0 0 39 810 0 0 0 78.8 0 0 0 48 A807 0 0 0 0 0 0 0 48 A808 0 0 0 0 0 0 0 53 A809 0 0 0 0 0 0 0 53 A810 0 0 0 0 1 0.4 0 0 1 2 3 4 5 6 7 8 9 10 <1.5 1.5-2.0 2.0-2.5 2.5-3.0 3.0-3.5 3.5-4.0 IRI range, m/km N um be r o f s ec tio ns Figure 3-65 Current IRI in SPS-8 sections