Substantial investment in the WesTrack Pavement Test Facility (WesTrack) by the Federal Highway Administration (FHWA) under contract DTFH61-94-C-00004 has assembled technologies, created a public/private sector team, and provided data necessary to produce essential pavement engineering and construction tools, such as performance-related specifications and evaluations of field performance of Superpave-designed hot mix asphalt (HMA).
The project was started in October 1994. Construction of the first pavement test sections on WesTrack, a 2.9-kilometer (km) oval loop in western Nevada, was completed in October 1995, and truck loading was initiated in March 1996. The two-year truck loading of the track was completed by FHWA in early 1998; all construction-related QC and performance survey testing was also completed in 1998.
FHWA expended $13 million of the total $14.5 million budgeted to complete the construction, trafficking, and related testing. Data analysis, PRS development, and reporting remain to be accomplished. However, development of the final products was at risk because the 1998 highway legislation, TEA-21, did not provide the final $1.5 million for the WesTrack contract. In November 1998, AASHTO approved the use of NCHRP funds to complete the remaining, specific work tasks in the current FHWA contract as NCHRP Project 9-20.
The objectives of this research were to (1) develop performance-related specifications (PRS) for HMA pavement construction by examining how deviations in materials and construction properties, such as asphalt content and degree of compaction, affect the eventual pavement performance; and (2) provide early field verification of the Superpave mix design method.
The project is complete. The final report has been published as NCHRP Report 455: Recommended Performance-Related Specification for Hot-Mix Asphalt Construction: Results of the WesTrack Project - [ Part A
, Part B, Part C
, Part D
, Part E
, Part F
, Part G
]. The forty-four supporting technical reports are available online as NCHRP Web-Only Document 111
. The HMA SPEC
software is not available for public distribution; it has been superseded by a PRS developed from the Mechanistic-Empirical Pavement Design Guide
software in Project 9-22. The WesTrack database can be downloaded here