Impact of aggregate gradation and type on asphalt mixture characteristics

This thesis addresses the impact of aggregate gradation and type on Hot Mix Asphaltic Concrete (HMAC) characteristics. Several different, but related topics are covered and results from several experiments are presented. An overview of HMAC is presented, covering factors affecting mixture characteristics and performance in addition to a review of the literature relating to aggregate gradation and type. The results of a study of construction data from the Texas State Department of Highways and Public Transportation (SDHPT) are presented. Two laboratory studies were conducted relating to asphalt content, aggregate gradation and aggregate type. The summarized results and interpretations of these results are included. The economic impact of specifications changes currently proposed by the SDHPT to improve HMAC quality is addressed. Finally, conclusions and recommendations are drawn based on all preceding material.