Date of Award

2026

Abstract

Efficient and effective rehabilitation of existing pavements is a continuing priority for transportation agencies seeking to maintain safe, reliable, and cost-effective networks. Asphalt overlays are widely used to restore ride quality and extend service life of both asphalt and concrete pavements; however, their long-term performance is often limited by thermal and reflective cracking. These distresses accelerate moisture infiltration, increase maintenance demand, and shorten overlay life, especially in cold-climate regions. Ensuring that overlay designs adequately account for structural configuration, traffic, climate, subgrade conditions, and mixture-level fracture resistance is therefore critical to avoid premature failure and excessive life-cycle costs.This dissertation advances performance-based design of asphalt overlays by integrating replicate-level data screening, laboratory cracking indices, field performance observations, and mechanistic modeling to improve prediction and selection of mixtures for thermal and reflective cracking resistance. First, a robust outlier detection framework was developed for asphalt mixture fracture tests to improve the reliability of performance indices prior to analysis. The approach uses parametric fitting of post-peak Load–CMOD curves and multivariate robust estimators to identify and remove abnormal replicates, thereby strengthening subsequent statistical inferences. Next, a comprehensive database of Minnesota overlay projects was assembled, integrating mix design variables, structural and traffic descriptors, climatic indicators, and Disc-Shaped Compact Tension (DCT) fracture indices. Multi-stage statistical analysis (bivariate and partial correlations, regression, and mutual information) was used to identify governing variables for roughness progression and cracking. Overlay thickness, truck traffic, low-temperature binder grade, soil type, and pre-existing cracking emerged as dominant drivers, while DCT-based fracture energy and post-peak indices provided additional mechanistic information. Complementing the network-level analysis, ten experimental overlay mixtures with different binder grades and modifiers (plastics, rubbers, and fibers) were evaluated at MnROAD under reheated and laboratory-aged conditions using a suite of low- and intermediate-temperature tests. Connecting Letters Report analysis and rank-difference comparisons with early field cracking data showed that the PG 58S-28 control mixture consistently exhibited the poorest performance, while softer PG-34 controls and fiber- or rubber-modified mixtures provided superior cracking resistance. Among the test indices, G-Rm, FI, and CPR demonstrated the strongest alignment with early field performance, with G-Rm offering a particularly practical balance of sensitivity and predictive capability. Finally, four mechanistic and mechanistic-empirical tools (AASHTOWare PavementME™, TxACOL, FlexPAVE™, and IlliTC) were applied using common traffic, climate, structural, and material inputs to predict thermal and reflective cracking. Comparison of model-based mixture rankings with observed early field reflective cracking showed that the three cracking-focused tools, TxACOL, FlexPAVE™, and IlliTC, consistently identified the PG 58S-28 control as a poor performer, with IlliTC achieving the closest overall agreement with the early field ranking based on the number of critical thermal events. Collectively, this work provides a unified, performance-based framework, from data screening to laboratory testing, statistical correlation, and mechanistic simulation, to support more reliable selection and specification of asphalt overlay mixtures for long-term resistance to thermal and reflective cracking.

Document Type

Dissertation

First Advisor

Eshan V Dave

Second Advisor

Fei Han

Third Advisor

Marek Petrik

Department or Program

Civil and Environmental Engineering

Degree Name

Doctor of Philosophy

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