Date of Award

8-2009

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Civil Engineering

Advisor

Putman, Bradley J

Committee Member

Amirkhanian , Serji N

Committee Member

Rangaraju , Prasad R

Abstract

The optimization of the available aggregates for highway construction and maintenance is vital both from an economic and environmental perspective. By not optimizing the aggregate supply project costs escalate as a simple response to supply and demand, and just as important the fact that aggregate is a natural resource and a limited one, it is crucial that is used as efficiently as possible. This paper examines specifically the use of aggregates by the South Carolina Department of Transportation, but can easily be adapted to any state. Through DOT and quarry surveys and an examination of aggregate gradation specifications it was determined what specific sieve sizes were significantly different than other states. These specific sizes were then examined to determine if an adjustment of the specifications could better utilize the available aggregates. It was found that times of high construction greatly affect the balance of aggregates, but also that gradation specifications could be adjusted in order to better use the available aggregate sizes. In South Carolina hot mix asphalt pavements is the primary source of over and under utilization. The 3/8-inch and 1/2-inch aggregates sizes are most over-utilized, and these sizes have a relatively tighter specification than other states across the Unites States. The recommendation is to further research performance of possibly wider specs that will utilize some of the more available aggregates in the state. In addition research was recommended in the use of the maximum dust to binder ratio as well as the possibility of a base substitution, which will better utilize the graded aggregate base. As long as performance and cost can be maintained these changes could better optimize the usage of the available aggregates in construction and maintenance.

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