Impact of Three State Practices on Effectiveness of Hot-Mix Asphalt Overlay

Abstract

The effectiveness of pavement treatments is a function of several factors, including material quality, design, distribution of pavement condition states (conditions and rates of deterioration) before treatment, and construction quality. Because of these factors, state highway agencies have established estimates of treatment service lives with significantly wide ranges. These wide ranges make the calculation of treatment benefits or effectiveness a difficult task unless the role of each factor that affects service life is well understood. This study analyzed the impacts of the state of the practice of Colorado, Louisiana, and Washington on the effectiveness of thin (< 2.5 in.) hot-mix asphalt (HMA) overlay treatment. This paper reports that analysis of time-series pavement condition and distress data of previously treated pavement sections can be tabulated in a matrix format to demonstrate a snapshot examination of past practice. Such matrices are called treatment transition matrices (T2Ms). The data in the matrices express the probability that a pavement treatment will have certain effectiveness. T2Ms for pavement projects subjected to thin HMA overlays by three state highway agencies are discussed. Differences in treatment effectiveness were related to differences in the state of the practice in the three states. Selection of treatment timing and project boundaries significantly affected treatment effectiveness, and similar states of the practice yielded similar treatment effectiveness.