Seal Coat Damage Evaluation Due to Superheavy Load Moves Based on a Mechanistic-Empirical Approach (0-5270-1)

The number of superheavy load (SHL) moves has increased drastically within the past 5 years in Texas. Along with the increasing SHL moves, the Texas Department of Transportation (TxDOT) has become increasingly aware of the rising concerns associated with fresh seal coat damage caused from SHL moves. Concerned about the effects of SHL moves on seal coat placed routes, TxDOT sponsored a research project with the Texas Transportation Institute to characterize critical factors related to the failure mechanism of seal coat, propose a mechanistic approach to evaluate failure potential, and develop a guideline for regulating SHL moves to mitigate further seal coat damages. This report describes research efforts and findings to propose a mechanistic approach to evaluate seal coat damage potential via charactering material properties playing a vital role in controlling seal coat behavior subject to SHL moves and validating the proposed mechanistic approach based on pilot field tests conducted in the Bryan and San Antonio Districts taking into account different levels of critical factors identified from this study. Moreover, the efforts were extended to establish a database on SHL routing information gathered from the TxDOT Construction Division from the pavement reviews conducted over the past 5 years in order to review the current guideline for SHLs. The project offered the first opportunity to provide a guideline for regulating SHL moves in order to preserve routes with fresh seal coats by delivering a tool that can be used to evaluate the route in a timely fashion before SHL moves occur.