EFFECT OF COARSE AGGREGATES ON THE DESIGN AND PERFORMANCE OF CRCP IN TEXAS

Abstract

This study, conducted by the Center for Transportation Research at The University of Texas at Austin, investigates the impact of coarse aggregate types on the performance of Continuously Reinforced Concrete Pavements (CRCP) in Texas. Texas State Department of Highways and Public Transportation specifications typically do not differentiate between aggregate types, assuming equivalent performance if certain criteria like grading and hardness are met. However, field observations have indicated significant performance disparities in CRCPs constructed with different aggregates, particularly crushed limestone (LS) and siliceous river gravel (SRG). Through extensive laboratory testing and the development of a mechanistic model (CRCP), this research evaluates the properties of concrete mixes containing LS and SRG aggregates, including their modulus of elasticity, tensile strength, thermal coefficient of expansion, and drying shrinkage. The findings suggest that aggregate type significantly affects CRCP performance, influencing crack spacing, crack width, and steel stress. Consequently, the study presents design charts enabling the construction of CRCPs with equivalent performance using either aggregate type. This research not only challenges the prevailing assumption regarding aggregate interchangeability in CRCP construction but also offers practical guidelines for pavement design that accommodates the distinct properties of LS and SRG aggregates. (Abstract generated by AI tool ChatGPT 4)