Controlling Early-Age Cracking in Continuously Reinforced Concrete Pavement: Observations from 12 Years of Monitoring Experimental Test Sections in Houston, Texas

Presented are findings drawn from 12 years of monitoring and analyzing thermal cracking in experimental continuously reinforced concrete (CRC) pavements placed in and around Houston, Texas. Between 1986 and 1995, 85 CRC test sections were built at eight locations (projects) in the greater Houston area. Each project consists of between 8 and 22 experimental sections of slightly different design. These sections were closely controlled and monitored during construction, and periodic condition surveys continue to be conducted. Adjacent placement of the experimental sections in each project minimized the effect of uncontrolled variables such as traffic and climate. The purpose of the study was to evaluate new design elements and construction considerations intended to control earlyage thermal cracking and cracking-related distress caused by coarse aggregate with a high thermal coefficient of expansion. Experimental factors considered include coarse aggregate type, percentage of steel reinforcement, bar size, double or single mat steel, paving time, and paving season. Findings from the study show significant differences in performance between low and high thermal coefficient aggregates, along with some effective methods to minimize them as well as some attempts that were not as successful. Aggregate type and placement season were found to be the most significant factors affecting PCC performance, whereas day or night placement, steel percentage, bar size, and skewed placement proved less significant.