Present Serviceability Rating Computation From Reported Distresses

The National Performance Management Measures; Assessing Pavement Condition for the National Highway Performance Program provided in Subpart C of 23 CFR Part 490 includes an alternative method to report pavement conditions for Interstate and non-Interstate National Highway System locations where the speed limit is less than 40 mph.(1) This alternate method uses present serviceability ratings (PSR) to report pavement condition in lieu of using the International Roughness Index, measures of rutting and faulting, and percentage of cracking where the posted speed limit is less than 40 mph. Per 23 CFR 490.309(b)(1)(iv), the portion of the Interstate mainline highway pavements where PSR is allowable includes border crossings and toll plazas.(1) To address stakeholder concerns about the appropriate application of PSR, the Federal Highway Administration (FHWA) developed resources to support agencies that prefer to use PSR as an alternate pavement-condition-rating system, where permitted. In addition, many agencies do not collect PSR on their pavement segments; instead, they use Pavement Condition Index (PCI) or other indices computed from measured surface distresses in their pavement management systems. In light of this, section 490.309(b)(2)(iii) also allows State DOTs to convert other pavement-condition-assessment methods (e.g., the U.S. Army Corps of Engineers PCI) to PSR if the State establishes to FHWA's satisfaction that the conversion produces pavement condition ratings equivalent to the PSR method. In support of this rule, FHWA has developed this report to provide an approach for estimating PSR from measured surface distress data. It also illustrates correlations between commonly used indices and the PSR, as described in the Highway Performance Monitoring System Field Manual.(3) The appendix includes a guide for using a Microsoft(R) Excel(R)-based PSR Computation Workbook that was developed to assists with estimating PSR from measured surface distresses.(2)

This interim report documents the field performance of nine concrete pavement projects that incorporate recycled concrete aggregate (RCA) in the construction of the pavement. Multiple sections were evaluated on many of the nine projects, due to perceived differences in performance levels or variations in pavement design (such as the use of virgin aggregate or the inclusion of dowel bars). All told, a total of 17 sections (of which 12 contain RCA) were subjected to an extensive field testing program, consisting of pavement condition surveys, drainage surveys, falling weight deflectometer (FWD) testing, coring, and serviceability assessments.