No abstract

No abstract

This study presents the development of a probability model for pavement slippage failure. A measurement method for a tack coat residual application rate in a field core through binder extraction was developed and verified. It was found that implementing a measurement method for tack coat quality acceptance is feasible. Pavement investigations were performed on two slippage failure cases in Indiana and confirmed that the residual application rates of slippage failed sections were significantly lower than those of non-failed sections. A slippage failure probability model in terms of residual application rates was developed through binary logistic regression analysis. The model can be used to determine appropriate residual application rates in consideration of its uniformity from a distributor and to develop tack coat specifications based on slippage failure probability.

SMA is to be designed based on SMA volumetric properties in terms of air voids content (Va), voids in the mineral aggregate (VMA), and adequate stone-on-stone contact. For construction quality assurance (QA) purposes, INDOT currently accepts SMAs based on aggregate gradation and asphalt binder content. Thus, there is a discrepancy between SMA design criteria and construction acceptance. To better align design and construction, it is necessary to consider SMA volumetric properties in the use of QA. For HMA mixtures, INDOT has already transitioned from volumetric QA acceptance procedures to PWL. Today, SMA still uses adjustment points not based on robust statistics for QA acceptance. SMA QA samples and QA data sets were collected from projects constructed in 2019 and tested in the laboratory. The Hamburg Wheel Track Test (HWTT) was performed on the 2019 QA samples to evaluate SMA rutting performance. Additionally, the PWL for HMA was applied to the 2019 SMA QA data to see if the HMA PWL method would work for SMA. Possible SMA QA measurements were compared to past QA data and HMA QA measurements. In addition, Voids in the Coarse Aggregate (VCA) was evaluated as a possible SMA QA measurement. Finally, using the suitable QA measurements for SMA, a PWL parameter study was performed to find PWL that provides a Pay Factor (PF) equivalent to the current SMA Adjustment Point (AP) PF. The current SMA QA measurements (binder content, gradation, and density) are recommended for Indiana's SMA PWL. Based on the results of applying PWL to SMA QA data for the last four years, SMA PWL specification limits are recommended. Also, the SMA PF equations are suggested to get the SMA PWL to have PF equivalent to the current AP PF.

The focus of this study is the evaluation of the effects of deficiencies in design-level values of effective binder content (ΔV_be) on the top-down and bottom-up fatigue cracking performance of hot mix asphalt (HMA) mixtures using AASHTOWare Pavement ME Design structural simulation program. Using an analytical-mathematical-based methodology, this study also aims to predict the reduction in fatigue service life (i.e., top-down, and bottom-up fatigue cracking) of asphalt pavements that are most sensitive to the variation (ΔV_be). Two types of mixes with varying levels of V_be are used to simulate the fatigue cracking performance of a full-depth pavement structure. For each of the three studied cases, one asphalt course has a variable value of V_be, while the two other courses have a fixed value of V_be. Results indicate that the ΔV_be of 3% reduced 50% to 70% of fatigue cracking service life. Additionally, Pavement ME shows a limitation to account for the effect of V_be in the intermediate course on the bottom-up fatigue cracking.