Date of Graduation

8-2025

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering (MSCE)

Degree Level

Graduate

Department

Civil Engineering

Advisor/Mentor

Braham, Andrew

Committee Member

Hall, Kevin

Second Committee Member

Sasidharan, Lekshmi

Keywords

BMD; LMLC; Long term performance; MEPDG; RPMLC; Superpave

Abstract

Asphalt mix design has advanced significantly since the 1930s, with Balanced Mix Design (BMD) emerging to address durability concerns found in the Superpave method by optimizing binder content based on performance criteria. The performance of bituminous mixtures can be assessed through laboratory testing. These tests require proper sample preparation, and various techniques are employed for this purpose. Understanding the differences between these techniques is essential for the successful application of bituminous mixtures in the field. The objective of this study is to assess the differences in the predicted long-term performance of two sample preparation techniques, Lab Mix Lab Compacted (LMLC) and Reheated Plant mix Lab Compacted (RPMLC). The study also assessed the differences in predicted long-term performance between Superpave mixtures and BMD mixtures. Predicted long-term performance was assessed using AASHTOWare Pavement ME software (MEPDG). The study found that RPMLC samples generally have a higher dynamic modulus than LMLC, resulting in lower IRI, permanent deformation, and bottom-up cracking but higher top-down cracking. These reductions ranged from 0.075% to 0.92% for IRI, 1.06% to 10.40% for total permanent deformation, 3.10% to 31.98% for AC layer deformation, and 0.58% to 3.75% for bottom-up cracking. Permanent deformation was notably affected by sample preparation, with RPMLC showing up to 32% variation compared to LMLC. A slight increase in top-down cracking was observed, while thermal cracking remained virtually unchanged, reflecting its weak dependency on dynamic modulus and stronger ties to binder and volumetric properties, which were similar between the mixture. Superpave mixtures had significantly higher IRI and thermal cracking than BMD mixtures, indicating BMD mixtures have better performance, with performance differences ranging from 251% to 611% for thermal cracking, clearly showcasing the benefits of BMD. RMSE proved to be the most effective metric for analyzing changes in dynamic modulus supported by R-squared values of 72% for total structural deformation and 74% for AC layer deformation, while pointwise differences were valuable for identifying directional trends. Overall, variation in dynamic modulus accounted for over 60% of the differences in IRI, 78% of the deformation in the asphalt concrete layer between LMLC and RPMLC, and approximately 40% of the variation in thermal cracking between BMD and Superpave mixtures.

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