Integration of Rolling Wheel Deflectometer Deflection Measurements into Pavement Management Systems

Abstract

The Louisiana Department of Transportation and Development (DOTD) conducted a research project with the rolling wheel deflectometer (RWD) on approximately 1,400 mi of asphalt concrete roadways. The major outcomes of the study were evaluation of the effectiveness of the RWD as a structural assessment tool on Louisiana highways and the introduction of the RWD index (RI). The purpose of this study was to define RI ranges for treatment selections or pavement structural conditions linked to current methods of the Louisiana DOTD's pavement management system; multivariate (factor analysis) and descriptive [analysis of variance (ANOVA)] statistical methods and fuzzy logic functions were used. The factor analysis revealed that the RI could be used as a single index for assessing pavement structural conditions. ANOVA revealed that the RI could not be used to establish the four treatment methods typically used by the Louisiana DOTD but that it could be used to infer whether a pavement was structurally sound or deficient. If the pavement were determined to be structurally deficient, additional structural evaluation, such as with a falling weight deflectometer, would be required. Fuzzy logic and set theory were used to establish fuzzy functions for structurally sound and structurally deficient pavement conditions along with RI threshold ranges per thickness group. Equations were derived to produce RI threshold values for pavement thicknesses less than 12 in. The equations may be used for pavements thicker than 12 in., but with caution. For large segments of roadways, algorithms were used to assess whether pavements were structurally sound or structurally deficient on the basis of RI.

Research Trends in Pavement Management during the First Years of the 21st Century: A Bibliometric Analysis during the 2000–2013 Period

“…Nevertheless, as these tools need to interrupt the traffic to operate, their use at the network level is limited, alternative devices are introduced, especially the rolling wheel deflectometer (RWD), because it can measure at traffic speeds. In Louisiana, an acceptable repeatability of RWD measurements at different test speeds was demonstrated [85], and the RWD index was developed as a useful index for pavement structural condition assessment, but not for selection of the correct treatment [86].…”

Evaluating pavement management treatment selection utilising continuous deflection measurements in flexible pavements

“…Table 1 presents the pavement treatments that correspond to the five pavement distress group ranges. Treatments 1 and 2 are generally structurally related, treatment 3 can be either structurally or functionally related, with the latter being the most probable, and treatments 4 and 5 are functionally related (Khattak et al 2007(Khattak et al , 2008Gaspard et al 2013). As presented in Table 1, multiple indices may be used to assign a treatment.…”

“…This limitation can be a source of error in the assignment of treatments (Gaspard et al 2013). The authors postulate that two types of errors exist because of the lack of consideration of structural conditions: adding structure to a pavement that does not require it (Type I error -false positive) and not adding structure to a pavement that requires it (Type II error -false negative).…”