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CHAPTER 3. DATA BASE DEVELOPMENT Introduction In this project, two separate types of information were collected and stored In a set of project data bases. These information types are agency survey data and project analysis data. The agency survey data stem from the following three sources: ~, , NCEURP project 20-7 task 53 (Scofield 1992) 1992 Salt survey. NCEURP project 1-31 1994 SELL survey. NCHRP project 1-31 1994 selected paving contractor survey. As discussed In chapter 2, the information In these surveys has been used to determine current practices and opinions regarding initial pavement smoothness specifications and testing procedures. In addition, the information has been used to indicate the general direction that States are taking with regard to their specifications and testing methods. ~i, ~ The project analysis data were used to evaluate He importance of initial smoothness and the effectiveness of ~rutial smoothness specifications. These data typically include pavement design, construction, and monitoring data on several highway study sections and pavement projects available from the following sources: . Past roaci tests (e.g., American Association of State Highway Officials [AASHO] Road Test, Western Association of State Highway Officials [WASHO] Road Test). On-going pavement performance studies (e.g., Long-Term Pavement Performance [LTPP] program, FHWA's Rigid Pavement Performance and Rehabilitation [RPPR] study). · Selected SHAs. The data are stored in He Microsoft Access data base management system. This system was selected for a variety of reasons. First, it allows for quick and easy entry of many types of data, as it is operable In bow spreadsheet and data form environments. Second, like over powerful data base programs, it has virtually unlimited capacity since it too operates as a relational data base. However, unlike those other programs, Access features suppler querying and reporting procedures. Most importantly, data contained in Access are easily exportable into Microsoft Excel _ _1_ ~ _1 ~ _ .1 ~ wn~ch) tor tins project, serves as a secondary data base manager. The computerized worksheet available in Excel not only allows quick statistical analyses and preparation of graphs, but also reduces concerns about being able to accurately query and retrieve data. 29
Description of Data Bases Agency Survey Data Bases Work on the agency survey data bases was initiated with the establishment of the NCHRP 20-7 task 53 State survey data base. The tables In this data base were structured such that States are listec! In the first column and the survey questions are listed, in order, in the column headings to the right. The State responses were then manually entered into the appropriate cells. Once He NCHRP I-31 State survey form was completed, the data base for this survey was fully structured using the same format as the NCHRP 20-7 survey data base. As State responses became available, the results were again manually entered into the appropriate cells. As part of the agency surveys, selected paving contractors were contacted in order to obtain the contractor's perspective on pavement roughness measuring procedures and practices. Both AC and PCC paving contractors were contacted. The same procedure for the clevelopment of the agency survey data base was followed for the contractor data base. Project Analysis Data Bases Work on the project analysis ciata bases began with the development of a list of anticipated data base elements. This list, shown in table 7, was prepared following the Strategic Highway Research Program (SHRP) LTPP Data Collection Guide (FHWA 1993), and contains the necessary data elements for conducting later analyses to address the following key project objectives: i. Determine the effect of initial smoothness on the ride quality of the pavement over its life and on pavement service life. 2. Determine the effect of existing smoothness specifications on He initial as- constructed smoothness. 3. Determine He cost-effectiveness of smoothness specifications, including incentives and disincentives. Sources of Data for Project Analysis Data Base Past Road Tests AASHO Road Test The AASHO Road Test represents one of the most comprehensive studies of pavement performance that has ever been conducted. Over 800 AC and PCC pavement study sections were constructed and evaluated from 1958 to 1960. 30
Table 7. Initial list of anticipated data base elements. Section Identification - State Project number Highway number County City Beginning station/milepost Ending station/milepost Direction of travel Functional classification Number of Peru lanes Construction date Pavement Design Information Pavement type Pavement structure (layers and thicknesses) Maintenance and Rehabilitation Information Activity description Date perfo~ed Begnunng location Ending location Extent of activity Distress Monitoring Information Year of measurement Distress types, severities, and quantities Traffic Monitoring Information Cumulative 18-km ESALS Average daily traffic (ADT 2-way) Average daily truck traffic (ADTI 2-way) Initial Roughness Information Equipment type and model Time performed after construction Loners) tested Unit length of paving section tested Positionts) tested Number of passes made per position Method of equipment calibration Roughness index used Roughness measurements Extended Roughness Information Equipment type and model Dates of testing Lanes tested Unit length of paving section tested Positions tested Number of passes made per position Method of equipment calibration Roughness index used Roughness measurements T~e-series serviceability data, based largely on slope variance measurements made win a longitudinal profiling device, were obtained for all of the sections. The AASHO Road Test data were obtained and entered into Excel spreadsheets. Rigic} pavement section data, such as pavement design, loading information, and present serviceability ratings (PSRs), were manually entered from appendix A of The AASHO Road Test Special Report 6IE (AASHO 1962~. Only He data for replicate study sections were entered, as only Hose sections allow for the direct comparison of serviceability trends. In addition, He PSRs provided In Special Report 6lE are smoothed ratings and represent only a portion of He ratings that were typically assigned on 2-week intervals over the 2-year study period. Sunilar data on the flexible pavement sections were obtained from a computerized ASCH file and were Imported into Excel. Unlike He rigid data, however, the flexible data contained cumulative load applications and unsmoothed serviceability ratings assigned at the specified 2-week intervals. I~ike before, replicate sections were then extracted from He original data file and placed into a second data file for direct · ~ examination. 31
WASHO Road Test Test data from the WASHO Road Test on various conventional AC pavement designs were found In The WASHO Road Test Part 2 (HRB, 19551. These data included initial anc! extended roughness measurements for the years of the road test (October 1952 through May 1954) using a Bureau of Public Roads (BPR) Road- Roughness Indicator. The roughness measurements, and corresponding load applications, of forty 300-ft (91.5-m) experimental sections were entered into Excel for analysis of roughness trends. San Diego County Test Road Test data on various AC pavement sections constructed as part of the San Diego County Experimental Base Project were also unearthed (Shook, 1976~. A total of 35 test sections, having different base types and Sicknesses, were included In this experunent, which was begun In 1966 and discontinued in 1973. The prime interest In this experiment was He serviceability trends of similar sections, as defined by cumulative equivalent IS,000-Ib (80-kN) s~ngle-axie loads (ESALs) and present serviceability index (PSI) calculations (determined In part by slope variance measurements made with the ChIoe profiler). Alabama Pavement Roughness Study A pavement study done by the Alabama Highway Department in the 1960s also yielded roughness data for analysis in the NCHRP 1-31 project (Holman, 1969~. This study involved initial and extended roughness testing of several AC and PCC pavement projects located on various Alabama highways. The roughness measurements were made with the BPR Road-Roughness Indicator on 0.5-mi (0.~-km) intervals, thereby resulting In time-series measurements for multiple, f~xed-~nterval highway sections. As with the other road tests, pertinent data were extracted from He report and entered Into Excel. Minnesota Flexible Pavement Design Study (Investigation IS3) In 1963, the Minnesota DOT began a study of many ~n-service, flexible pavement sections located on various trunk highways throughout the State (Kerston and Skok 1968~. The purpose of the study was to evaluate the flexible pavement design procedures used by the department at that time and to determine how He findings and concepts of the AASHO Road Test could be applied to their pavement design procedures. A total of 50 pavement sections, built or overlaid in He late 1950s and early 1960s, were identified and monitored for performance Trough 1967. The sections were conventional AC designs, with asphalt layer thicknesses ranging mostly from 1.5 to 7.5 in (38 to 190 mm) and granular base layer thicknesses ranging from 6 to 22 in (150 to 560 mm). Roughness measurements were made win He BPR Roughometer, both at the time of construction and during each of the 5 years (1963 through 1967) 32
that the sections were evaluated. Pertinent data were extracted from the report and entered into Excel for analysis. On-Going Pavement Performance Studies LTPP The LTPP program is a coordinated, 20-year nationwide study of pavement performance. The program consists of General Pavement Studies (GPS) and Specific Pavement Studies (SPS). The GPS is of ~n-service pavements and consists of 866 flexible and rigid sections. The SPS is targeted at specific issues In pavement performance and contains specially constructed sections. A COpy of release 6 of the GPS data base was obtained in January 1995, with submission of nearly complete data tables for all nine GPS experunents (i.e., GPS-! through GPS-9~. A major problem noted with the GPS data was the absence of nutial roughness measurements. For every GPS section, only extended roughness measurements for the years 1989 through 1993 were available. Although the recent SHRP P020 project (Daleiden, et al., 1994) was found to contain estimates of initial PSIs for many of the GPS test sections (the PST data were either calculated from initial roughness measurements, extrapolated and calculated from subsequent roughness measurements, or estimated using project records, specifications, or personal experience), the estimates were not deemed reliable enough to use for analysis. To make use of at least some of the data, however, several GPS sections built after 1986 were identified for possible analysis. Consideration was given to allowing He first LTPP roughness measurements (1989 and 1990) to serve as the Initial roughness values for these sections, despite a lag of up to 3 years following construction. In November, 1994, and October, 1995, attempts were made to collect and evaluate LTPP SPS data. However it was found that the data were either not available or had not passed the minimum level of quality checks. RPPR An on-going study being conducted for He Federal Highway Adm~rustration (FHWA) on rigid pavement performance is another source of data for the NCHRP 1-31 project (Smith, et al., 1995~. Pavement sections in He RPPR study range between 12 and 27 years in age and differ foremost by pavement type, cross-section, and base type. Initial and intermediate roughness measurements were made on some of the sections using measuring devices that varied from State to State. In 1992, roughness measurements were made on all sections using a South Dakota-type profiler. 33
Selected State Highway Data Although the above sources provided data useful to the study, the SHAs were the primary focus In the data collection and analysis process. To help identify candidate sources) agencies were asked the following questions on the State survey: Type of roughness measuring equipment used on new construction? Type of roughness measuring equipment used for extended monitoring? ~ Availability of iriitial roughness data on AC, PCC, and AC overlay pavements? · Availability of extended roughness data on AC, PCC, and AC overlay pavements? Agency's willingness to provide roughness data for examination? . Based on the responses to these questions, several States were identified as potential sources for supplying pavement project data. In anticipation of soliciting data from selected SHAs, a two-part data request package was developed, which consisted of a statement of request for pavement project data, a synopsis of He current study, and a detailed list of the types of data needed for several pavement projects. The first part of the data request package pertained to the solicitation of initial and extended pavement roughness data. These data were to be used In the analysis of initial pavement smoothness versus both ride quality over a pavement's life and pavement service life. Pavement projects targeted in this request included those with specific pavement designs (e.g., AC full-depth, CRC) that are largely available In the selected State and have been in service for several years. The second part of the data request package pertained to the solicitation of comprehensive pavement design and construction data. These data were to be used In analyzing the effect of initial smoothness specifications on Initial smoothness and in assessing He cost-effectiveness of crucial smoothness specifications. Pavement projects targeted in this request included those with specific pavement designs built both before and after the unplementation of a smoothness specification. In order to gauge the difficulty of obtaining He required data and to better estimate the number of States to ultimately target, He research team ~rutiated pilot data collection efforts with He Illinois Depar~anent of Transportation (DOT) and the California DOT (i.e., CALTRANS). The data collection experiences at bow agencies provided the team win a better sense of the types of data that could reasonably be requested. Two separate data collection rounds were made in order to maximize the amount of data for analysis. The following summarizes the results of those data collection efforts carried out win the selected SHAs. 34
IZZinois The Illinois DOT provided historical files containing roughness measurements taken of newly constructed highway pavements built throughout Illinois between 1959 and 1990. These roughness measurements were taken with the BPR Roughometer along I-mi (~.6-km) intervals keyed by station number. Extended roughness data were also available for all interstate highways. As such, several interstate sections, having BPR Roughometer test results, were identified for examination. Each of these sections were at least 5 mi (S km) in length so that the roughness trends of multiple replicate sections (i.e., sections with the same design, traffic, and climate) could be examined. Data tables were developed for each of these projects that inclucled general information (e.g., location, clesian, etc.) about each project, as well as the initial roughness measurements. -c' ~ The extended roughness data kept by the Illinois DOT consisted of IRI measurements keyed by milepost and taken on 0.~-mi (0.16-km) Intervals using a Soup Dakota-type profiler. Extender] roughness measurements for the subject interstate projects for the years 1990 through 1993 were furnished by Me DI~nois DOT in hardcopy form. These data, along with pavement monitoring data obtained from the Illinois Pavement Feedback System (IPFS), were then entered into the data tables previously created. The majority of projects selected for analysis from Bl~nois were CRC. Of 41 total projects, 37 were CRC, 2 were AC overlays on CRC, and 2 were AC overlays on JRC. Although several IRC paving projects were completed In the early 1960s, all of those projects have since been overlaid two or three times. California In conjunction with the Illinois data collection effort, a series of visits were made to CALTRANS to determine the availability and suitability of their data. Through these visits, it was learned that the historical roughness data was generally not adequate for analysis. This determination was made during the process of obtaining and examining a sampling of historical roughness data on several highway projects In District 8. Among the reasons for excluding these data were the following: . . ,~ No specific initial roughness values were available for projects older than 2 to 3 years. All PCC pavements and some AC pavements were built to meet a specified roughness level (profile index < 7 ~n/mi [0.~! m/km] for PCC and < 5 in/ml ro.os m/km] for AC) and the resulting orofilo~ranh test orc~file.s _ _ , , , _ , _, ~ ~_ were typically retained for only 2 to 3 years. ~. ~ -to A- o---r-- ---- r------ Extended roughness testing was not performed consistently on a fixed-~nterval basis. Extended roughness measurements were begun by the Pavement Management Division in 1978. A fleet of PCA Roadmeters was deployed every 2 years to monitor the roughness of every lane-mile of highway pavement in California. Depending on the relative roughness of a project, 35
measurements were made on intervals between ~ and 3 mi (~.6 and 4.83 km) long. Maintenance treatments and rehabilitation work for portions of a given pavement project further compounded the ability to generate accurate time- series roughness data. Arizona The Arizona DOT provided an initial data package contairung historical roughness data on 12 highway projects. This package included three individual paving projects for each of four general pavement designs (AC, JPC, AC/AC, and AC/JPC). Each project inclucLed initial and extended roughness measurements taken on 1-ml (~.6-km) intervals using the Mays Meter. General information (e.g., location, design), traffic estimates, and conclition survey data was also provicled for each project. The Arizona DOT provided a second data package containing historical roughness data on ~ additional highway projects (2 JPC, 3 AC, and 3 AC/AC). As with their first package, each project included initial and extencled roughness measurements taken on 1-ml (~.6-km) intervals using the Mays Meter. Likewise, general information on each of these projects was also provided. Georgia The Georgia DOT also provided historical roughness data in response to both data requests. Their first package included data on 12 individual paving projects-three projects for each of the same four pavement designs (AC, lPC, AC/AC, and AC/JPC) proposed by the Arizona DOT. Their second package included data on three AC/AC projects and three AC/JPC projects. Each of the 18 total projects Included initial and extended roughness measurements taken on I-mi (~.~km) intervals using a modified Mays Meter. General project information, traffic estimates, and maintenance Information were also furnished for these projects. Comprehensive initial roughness data for the State of Georgia was contributed to the study shortly after its outset. These data, which consisted of summary-type roughness measurements for all new construction and resurfacing projects occurring between 1980 and 1995, were entered into Excel for the purpose of examining the effects of initial smoothness specifications on initial pavement smoothness. Additional statewide initial roughness trends, spanrung the years 1968 through 1980, were also made available for analysis. Towa Historical roughness data on Free JPC pavement projects were submitted by Me Iowa DOT. Initial roughness measurements for these projects were made with the California profilograph on 0.~-mi (0.16-km) intervals, whereas extended roughness measurements were made with the International Cybernetics Corporation (ICC) MDR 4090 South Dakota-type profiler on 0.025-mi (0.04-km) intervals. General information and traffic estimates were also provided for these projects. 36
Iowa also possessed comprehensive initial roughness data. Various summary- type roughness data were provicled by the Iowa DOT for new AC and PCC construction and AC resurfacing projects completed between 1982 and 1993. These data included California profiIograph measurements, South Dakota profiler measurements, and BPR Roughometer measurements of both primary and secondary highway facilities. Kentucky The Kentucky Department of Highways (DOH) provided pavement management evaluation forms on nearly all interstate and parkway pavement projects in Kentucky. These forms contained general project Information, condition survey results, and summary-type rideabilitr indexes (RI) computed annually from the time of construction. The RIs were derived from roughness measurements taken by response-type road roughness measuring systems (RTRRMS), the most recent of which is the Mays Meter. Detailed RIs for 20 selected Interstate and parkway projects were also provided by the Kentucky DOH. These projects, which included four different pavement types JPC, AC, AC/JPC, and AC/AC), were all constructed after 1980 when Mays Meter test results for I-mi (~.6-km) evaluation Intervals became available. Michigan A total of 47 Interstate and primary highway projects throughout Michigan were originally identified for historical roughness analysis. These projects included IS PCC pavements, 17 AC pavements, and 12 AC/PCC pavements, built during He 1970s and mid 1980s. The extended roughness data obtained during He on-site visits were for the years 1989 Trough 1994, and were made on 0.~-mi (0.16-km) intervals using a GM ProfiIomeler~. Although, it was later discovered that nutial roughness data were unavailable for many of the sections, a few of the original 47 projects those with time lapses between construction and the first roughness measurement of 3 years or less were stiD considered In He analysis. Minnesola A total of 26 AC, PCC, and AC overlay construction projects were identified In Minnesota, located on various Interstate, U.S., and State highways. A summary of the data provided by Minnesota includes the following: GM ProfiIometer~ root-mean-square (RMS) and BPR Roughometer roughness index data on I-mi (~.~km) Intervals for all selected PCC projects. Time-series IR] (South Dakota-type profiler) and PSR data on 1-ml (~.6-km) intervals for all selected projects. Traffic data for all selected projects. Distress (surface rating [SR]) data for all selected projects. 37
Cross-section and construction/rehabilitation data were also made available. Since lime-series IR] data were only available starting In 1989 and since construction acceptance testing of AC (new and overlay) projects was not formally begun until 1995, AC project selection focused on the construction years of ~ 988 through 1991. This way, the time lapse between construction and the first roughness measurement was usually limited to 2 years and at least 4 to 5 years of roughness trends could be analyzed. The selected PCC projects consisted of pavements built between 1985 and 1991. These projects were tested for construction acceptance using a GM ProfiIometer~ and, in a few instances, the BPR Roughomeler. Washington The Washington DOT provided historical roughness data on various interstate and primary highway projects throughout Washington state. These data included test results from various pieces of inventory testing equipment used over the years by the pavement management group. From about 1972 through 1976, a Mays Meter was used to measure roughness (on 1-ml [~.~km] Intervals) of highway pavements every other year. Then, from 1977 through 1990, a Cox PCA Roadmeter was used on an annual or biennial (every two years) basis to measure roughness on the same Interval. Finally, starting in 1991, a South Dakota profiler was used annually to measure roughness on 0.~-mi (0.16-km) intervals. A total of 22 AC, PCC, and AC overlay projects were selected for analysis, win most being built In the mid to late 1970s and the early to mid 1980s. Cross-section, traffic, and ma~ntenance/rehabilitation data for the selected projects were obtained In conjunction with the time-series roughness data. Although Washington has tested new PCC pavements for construction acceptance since about 1973 (using the California profiIograph), these records were not available. However, nearly all of the projects included pavement management tests performed within 2 years of construction. Wisconsin The Wisconsin DOT provided a substantial amount of roughness and serviceability data on several interstate and trunk highway projects In Wisconsin. Other key types of data, including cross-section, traffic, distress, and maintenance/rehabilitation information, were also available. The PS] data spanned the years 1980 to 1995, with interstate projects having annual measurements and Me trunk highways having measurements every other year. The PST data for the years 1980 through 1989 were computed from Wisconsin (Mays) Road Meter roughness measurements using statistically derived conversion equations. Starting In 1990, a South Dakota-type profiler was used to measure 38
roughness, which likewise was converted to PST using regression equations. In most instances, the first roughness/serviceability measurement for post 1979 construction projects was taken the same year that the project was opened to traffic. Some projects, however, were noted as having the first measurement the year following construction completion. Summary Many data sources were tapped In order to obtain useful historical roughness data for examination under this study. Not all of the anticipated data were obtained, but those that were obtained were thoroughly processed and entered into a data base. A summary of the data base development effort is provided In table S. This table shows the types of data that were targeted from We various sources and the status of the data compilation work. 39
Table S. Summary of data sources for analysis data base. ~Type of Data ~Data Received, Processed, ~ lData Source ~Available | Analyzed l AASHO Road Test ~Serviceability Yes WASHO Road Test ~Roughness Yes San Diego County Road Test ~Serviceability Yes ~ Alabama Roughness Study ~Roughness Yes ~ l Minnesota Investigation 183 ~Serviceability Yes l _ v LTPP GPS I Roughness 1es l RPPR l Roughness . es l 1 Arizona l Roughness Yes l l Georgia T Roughness Yes l l Illinois l Roughness Yes l ~Iowa r Roughness Yes l l Kentucky l Roughness Yes ~ 1 Michigan l Roughness Yes l l Minnesota l Roughness Yes l l South Dakota l Roughness Yes l l Washington l Roughness Yes l I . l Serviceability Yes l Wisconsin l (some roughness) l 40
