Date of Award

2023-05-01

Degree Name

Doctor of Philosophy

Department

Civil Engineering

Advisor(s)

Soheil Nazarian

Second Advisor

Imad N. Abdallah

Abstract

The engineering properties of asphalt mixtures change with time. Shortly after placement, asphalt concrete (AC) layers are more susceptible to rutting. As the pavement ages, the AC layer becomes stiffer, brittle, and thus more susceptible to cracking. Current protocols provide guidelines for the selection of materials, the determination of the material proportions (e.g., aggregates and binder content), and the evaluation of the engineering properties (e.g., cracking and rutting potentials) of any given asphalt mix design. However, these protocols do not consider the impact of aging on the mixture. This study investigated existing and novel laboratory methods to determine protocols that simulate the two aging states needed to design an asphalt mixture to resist rutting and cracking and provide information on how curing affects the physical and engineering performance of binders and mixtures. This study leveraged existing research studies and available performance data along with a systematic test matrix to optimize the curing conditions. The wide range of tests conducted in this study indicated that the minimum time to achieve levels of long-term aging using an optimized laboratory protocol would be close to 24 hrs. The steady state of aging for ranking different mixes may be adequately achieved after a period of 24 hrs (including 2 hrs of short-term aging) by aging loose mixture in a conventional laboratory oven. The efficiency of another aging protocol using pressure to accelerate aging has been demonstrated. This method can be used to characterize the performance of mixes more accurately under long-term aging within a period of 24 to 48 hrs.

Language

en

Provenance

Recieved from ProQuest

File Size

p.

File Format

application/pdf

Rights Holder

Benjamin Arras

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