Semester

Spring

Date of Graduation

2014

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

John P. Zaniewski

Committee Co-Chair

John Quaranta

Committee Member

Avinash Unnikrishnan

Abstract

In recent years there have been several instances of premature failures of pavements in West Virginia due to rutting. While there are various potential causes for the failures, aggregate density within the mix when designed at 80 gyrations was of specific concern to this thesis and was compared to the maximum dry density of the aggregate as measured using ASTM D4253-00. The objective of this research was to determine if the aggregate in the asphalt concrete mixture was reaching a dense configuration.;The Bailey Method was used to choose gradations and the selected research methodology supported the evaluation of the Bailey Method as a means for estimating changes in mix volumetric properties with changes to aggregate gradation. Aggregate density at various locking point definitions, as well as, N des and Nmax of 80 and 125 gyrations respectively, were evaluated to assess the effects of compacting to current Ndes level versus locking point.;Statistical methods were used to analyze the various test results including, line of equality charts and t-tests to test for equality. All results were evaluated at a 95% confidence level for consistency. It was determined that the aggregates in the asphalt concrete specimens achieved a dense aggregate structure when compacted to 80 gyrations when compared to the dry density specimens. Also, as the CA ratio increases the IDT strength increases indicating more resistance to rutting in the field. This could be a useful tool in choosing a gradation as the CA ratio can be determined from the gradation.

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