Date of Award


Degree Name

Master of Science


Civil Engineering


Soheil Nazarian

Second Advisor

Imad Abdallah


The use of recycled materials in Asphalt Concrete (AC) mixes is highly promoted in the transportation industry. Recycled materials minimize the use of virgin materials, reduce the consumption of resources, and cut costs for new construction or rehabilitation projects. The incorporation of Reclaimed Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS) in the AC mixture is promoted as long as equal or improved performance is achieved. The Texas Department of Transportation (TxDOT) is currently placing asphaltic concrete (AC) mixes that are lasting less than their expected performance life when recycled materials are used.

The objective of this Thesis is to present a performance comparison between virgin mixes and recycled mixes placed in Texas. The study includes a network level analysis that contains merged data from four different TxDOT databases at a statewide level from 2008 to 2015. Results from the Hamburg Wheel Tracking Test (HWTT) and Indirect Tensile Strength (IDT) were used in order to better understand the impact of the recycled materials in the laboratory performance. Similarly, life predictions in terms of fatigue cracking were incorporated into the study. At project level, results from the HWTT, IDT and Overlay Tester (OT) were used to characterize the performance of the AC mixtures in the laboratory. Field performance results were obtained through the collection of condition surveys that include cracking and rutting surveys.

The data merging process from different databases permitted the evaluation of the impact of RAP and RAS in the AC mix performance. The integration of the network and project level data lead to a better understanding of the use of recycled materials in Texas, their laboratory performance and their susceptibility to fatigue cracking and rutting.




Received from ProQuest

File Size

83 pages

File Format


Rights Holder

Berenice Salaices Gomez