APPENDIX A. SPS-1 PROJECT SUMMARIES

Appendix A includes an overview and summary of each SPS-1 project relative to the experiment plan.  Each overview includes a general description of the project’s location and specific values for the key factors of the experiment factorial (table 1).  Any deviations from the initial project nomination and any difficulties reported during construction are identified and briefly discussed.   In addition, a summary of the materials data that are available is provided herein.  As stated in chapter 2, the number of tests required for each project varies with the number of supplemental sections built within each project.

A summary of the data completeness for each project is presented in tabular format for the construction and the monitoring data elements. Data completeness and any project deviations are used in determining an adequacy code that is assigned to each project.  This code represents a numerical scale from 0 to 5 and provides an overall rating of the project in regards to fulfillment of the original experimental objectives and expectations.  A definition of this numerical scale is given below.

ALABAMA

The Alabama project was built on U.S. 280 east of Opelika, AL, in 1992.  U.S. 280 is a four-lane road with an estimated 16 percent trucks.⁽¹⁷⁾  It was estimated that this project would  receive 237,000 ESALs annually.  The project was constructed with AC shoulders.

The project was planned for the wet-no-freeze environmental zone with a fine-grained subgrade and would fill column N of the experiment factorial (refer to table 1).  The subgrade found on the project varied from lean clay with sand to sandy silt.  All samples showed that the subgrade fell into the fine-grained category.  The project site receives 1,340 mm of rainfall each year on average and has an annual freeze index of 9 °C-days, which is considered to be a wet-no-freeze climate.

This project includes sections 010101 through 010112 in the experiment design and also includes three supplemental sections.  Table 43 contains a summary of the data available for this project. It also provides the pavement section design for each section of the project.  

Construction Difficulties

During construction, a mechanical problem was encountered with the track paver used to place the HMA material.  The paver was repaired and the paving operations were restarted.  Just after paving operations began again, rain began to fall.  The rain delay caused some of the material to be laid at temperatures below the optimum compaction range. 

Several days later, further mechanical problems were encountered with the paver.  At this point, the track paver had to be abandoned.  A construction joint was placed in section 010111 and paving operations were continued using a rubber-tired paver.  Although great care was taken when paving on top of the PATB layer, some deformation was noticed on the layer when temperatures reached 29 °C. In addition, some heavy vehicle traffic was noted on top of the PATB layer prior to the placement of the ATB layer.  The contractor was notified of the problem and construction traffic was limited from that time forward until the PATB layer was protected adequately.  No other problems were noted during construction of the project.

Project Deviations

This project was not recorded as having any significant deviations.  Appendix B contains a set of tables that compares the guidelines for construction of an SPS-1 project to actual as-built project information.  Several of the sections deviated from the thickness requirements by more than 6 mm, which is the requirement set by FHWA.  The DGAB contained more material passing the No. 200 sieve than allowed.  The other requirements for which data was present in the IMS indicated that this project did follow the recommended guidelines.

Data Completeness

Table 43 summarizes the monitoring data that were available for this project.  As shown in this table, the longitudinal profile, transverse profile, distress, and FWD data meet the biennial data collection requirements.  The requirements for initial data collection for these elements were met.

Table 44 provides a summary of the testing data available for this project.  While most of the testing has been completed on the subgrade, the remaining layers still require a substantial amount of testing.

This project does not have any traffic data.  This section has neither WIM data nor ESAL estimates from the State.  The ESAL estimates from the State have been used previously to fill in years where WIM data was not collected.

The AWS for this project includes 1,394 days of data although the project has been completed for 2,282 days.  However, the directive requiring the installation of the AWS was not published until September 12, 1994, more than 1 year after the completion of the Alabama SPS-1 project.  This project has a complete set of climatic data from the NOAA database.

Table 43.  Summary of key project monitoring data for the Alabama SPS-1.

Site key information summary

Key monitoring data availability summary — Number of tests recorded in I MS to date

Table 44. Summary of available materials testing data on the Alabama SPS-1.

ARIZONA

This project was built on U.S. 93 north of Kingman, AZ in 1993.  U.S. 93 is a four-lane road with an estimated 34 percent trucks. It was estimated that this project would receive approximately 3.7 million ESALs over a 20-year design period.

The project was planned for the dry-no freeze environmental zone with a coarse-grained subgrade and would fill column Y of the experiment factorial.  This project has an average annual freeze index of 1 °C-days. On average, 241 mm of rain falls each year on the project.  The subgrade ranged from a clayey sand with gravel to a well-graded gravel with silt and sand.  All samples of the subgrade were coarse-grained materials.

This project includes sections 040113 through 040124 in the experiment design and four State supplemental sections.  Section 040159 was renumbered as 04A901. Table 45 contains a summary of the available data for this project. It also provides the pavement section design for each section of the project.

Construction Difficulties

An inordinate amount of rain fell on the subgrade during preparation and prior to paving.  The subgrade became excessively saturated.  Portions of the fill material began pumping.  However, these areas were replaced prior to paving operations.⁽¹⁸⁾

Project Deviations

Several sections were built with a thickness outside the 6-mm range allowed by the construction guidelines. In particular, Section 040122 was to be constructed with a base of ATB over PATB.  The data show that this section includes a layer of DGAB.

The DGAB on Sections 040119 and 040122 did not meet the gradation requirements.  The lift thickness used on Sections 040114 and 040121 was larger than that noted in the construction guidelines.  Also, the gradation requirements were not met for the surface HMA mix.

Data Completeness

Table 46 provides information about the materials data available for this project.  The materials testing on this project appears to be essentially complete, with the following exceptions:

• The permeability test has not been run on the DGAB or the subgrade layer.
• Resilient modulus testing has not been completed on the DGAB nor is the moisture content information available for this layer.
• Finally, the ATB and HMA surface layers do not have results from the moisture susceptibility test or the NAA test for fine aggregate particle shape.

On average, the monitoring requirements have been met for the longitudinal profile, FWD, distress, and rut depth monitoring as shown in table 45.  However, the requirements for the initial monitoring were not met.

Traffic data are available for 5 years of monitoring.  For all of the sections within the project, 1,544 days worth of WIM data are available.

This project has approximately 1,480 days of AWS data of the 2,129 days after construction.  However, this project was completed approximately 1 year prior to the requirement for an AWS.  This project has 17 years of data from the NOAA database.

Table 45. Summary of key project monitoring data for the Arizona SPS-1.

Site key information summary

Key monitoring data availability summary — Number of tests recorded in I MS to date

Table 46. Summary of available materials data on the Arizona SPS-1.

ARKANSAS

The Arkansas project was built on U.S. 63 southeast of Jonesboro, AR, in 1992.  U.S. 63 is a four-lane road with an estimated 20 percent trucks.⁽¹⁹⁾  It was estimated that this project would annually receive 170,000 ESALs.  The project was constructed with AC shoulders.

The project was planned for the wet-no freeze environmental zone with a coarse-grained subgrade and would fill column Q of the experiment factorial.  This project has an average annual freeze index of 47 °C-days.  On average, 1,224 mm of rain falls each year on the project.  The subgrade samples were classified as either poorly graded silt with sand or silty sand.  All samples of the subgrade were coarse-grained materials.

This project includes sections 050113 through 050124 in the experiment design.  The State did not build any supplemental sections at this site.  Table 47 contains a summary of the data available for this project. It also provides the pavement section design for each section of the project.

Construction Difficulties

During placement of the edge drains, the contractor discovered that there was insufficient fabric available to overlap on to the pavement as specified.  The edge drain was removed and replaced in accordance with the specifications.

Rain also caused delays during construction.   It was noted in the construction report, however, that the surfaces were allowed to dry prior to resuming construction in each case.

Project Deviations

Several sections did not meet the maximum 6-mm variation from the specified thickness. In particular, the average thickness of the DGAB on Section 010114 was less than half of the required thickness.  A review of the minimum and maximum thicknesses from the rod and level surveys illustrates that none of the sections met the required thicknesses.

A further review of the construction data shows that the surface HMA mix did not meet the mix design requirements.   The mix design was to meet a minimum stability of 8 kN with a flow between 2 mm and 4 mm.  The surface mix on this project had a stability of 7.9 kN and a flow of 1.8 mm.

Data Completeness

Table 47. Summary of key project monitoring data for the Arkansas SPS-1.

Site key information summary

Key monitoring data availability summary — Number of tests recorded in I MS to date

The longitudinal profile, FWD testing, and distress surveys all met the requirements for long- term monitoring.  However, the transverse profile measurements have not met this requirement. In addition, none of the monitoring was conducted within the time requirements for the initial site visit.

Traffic data are available for 1 year on this project.  These data include 89 days of continuous WIM measurements.

This project includes more than 1,100 days of AWS data of the 2,007 days after construction.  This project was completed prior to the directive requiring the installation of an AWS.  This project also has 17 years of climatic data from the NOAA database.

Table 48. Summary of available materials testing data on the Arkansas SPS-1.

DELAWARE

The Delaware project was built on U.S. 113 close to Ellendale, DE, in 1995.  U.S. 113 is a four-lane road with an estimated 10 percent trucks.⁽²⁰⁾  It was estimated that this project would annually receive 203,200 ESALs.  The project was constructed with AC shoulders.

The project was planned for the wet-freeze environmental zone with a coarse-grained subgrade and would fill column L of the experiment factorial.  This project has an average annual freeze index of 58 °C-days. On average, 1,145 mm of rain falls each year on the project.  The subgrade samples were classified as poorly graded sand.  All samples of the subgrade were coarse-grained materials.

This project includes Sections 011001 through 011012 in the experiment design and two supplemental sections.  Table 49 contains a summary of the data available for this project. It also provides the pavement section design for each section of the project.

Construction Difficulties

Some of the shoulder probes were unable to be completed at the required depth of 6 m due to a high water table. In addition, some of the Shelby tubes were unable to collect samples of the subgrade soils for no obvious reason.  The ditches on the sides of the project were shallow, which prevented the outlets for the edge drains from being placed at the recommended 76-m spacing.

Project Deviations

The average thickness of at least one layer on all of the sections, except Sections 011001 and 011002, deviated from the design thickness by more than 6 mm.  The maximum and minimum for every layer for every section deviated from the design thickness by more than the allowable 6 mm.

The gradation of the aggregate in the HMA surface mix did not meet the required less than 40 percent passing the No. 4 sieve.  The other requirements listed were generally followed.

Data Completeness

Table 50 contains a summary of the materials testing data available for this project.  The materials testing on this project is partially complete.  The only test results available for the subgrade are the resilient modulus tests.  The base layer only has permeability testing completed.  The only tests remaining for the HMA layers are the moisture susceptibility and the maximum theoretical specific gravity.

Table 49.  Summary of key project monitoring data for the Delaware SPS-1.

Site key information summary

Key monitoring data availability summary — Number of tests recorded in I MS to date