Date of Award

January 2020

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Civil Engineering

First Advisor

Daba S. Gedafa

Abstract

In the United States (US), there are more than 2 million miles of paved roads. About 93 percent of those are surfaced with asphalt mixtures (flexible pavements). Shortage of natural resources, environmental impact of pavement life cycle and pavement distress are the major concerns of the pavement industry. Higher percentage Reclaimed Asphalt Pavement (RAP) usage, alternative asphalt pavement additives and development of performance related pavement analysis are the major factors to improve sustainability of the pavement. In this dissertation, extensive studies were conducted on the use of sustainable materials and performance analysis. Use of Waste Cooking Oil (WCO) and Soy Oil (SO) modified high percentage RAP asphalt pavement and the potential use of wastewater sludge (WWS) as compaction aid additive and Warm Mix Additive (WMA) were investigated. Rate dependent normalized low-temperature cracking performance analysis was also conducted to better differentiate between the mixes and for better correlation with mix design parameters. Results showed that using 15% SO and 12.5%WCO with 2.5%virgin binders as rejuvenator it is possible to recycle 85%RAP binders (72.5% based on aggregate weight) while maintaining similar performance as compared to the control Hot Mix Asphalt (HMA). The optimum dosage of WWS based on Performance Grade (PG) 58-28 binder was 1%. The use of 1% WWS as additive significantly improved the fatigue and low-temperature cracking performance of modified mixes compacted at 50°F lower compaction temperature than the control HMA. Based on the effect of WWS on field mixed lab compacted HMA project results, it is inferred that WWS is a potential pavement compaction aid and performance enhancer additive. Generally, it improved the cracking performance of the HMA and reduced the compaction effort by maintaining the rutting performance within the specifications limit. It was also concluded that WWS improved fatigue and low-temperature cracking resistance of the control (0 %), 40% RAP, and 60% RAP mixes using RAP from two different sources and different age. The effect of WWS on fatigue cracking performance increased with RAP content, while the effect of WWS on low-temperature cracking decreased with RAP content. The WWS can be used as a compaction aid for longer construction season and lesser energy consumption. Results also showed that rate normalized GF parameters better differentiate mixes with high RAP content. The results also correlated better with binder performance and percentages of RAP content in the mix.

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