Pilot Implementation of Optimized Aggregate Gradation for Concrete Paving

摘要

In an effort to identify the benefits of using optimized aggregate gradation (OAG) in paving concrete, three test sections were constructed; each in Wichita Falls (US287 northbound), Fort Worth (SH114B northbound), and Dallas (SH121 westbound) Districts. Both normal aggregate gradation (NAG) and OAG sections were placed side by side in Wichita Falls project. Only OAG sections were placed in Forth Worth and Dallas projects. Fresh and hardened concrete properties of NAG and OAG concretes in Wichita Falls project and OAG concrete in Fort Worth and Dallas projects were evaluated. For the evaluation of pavement performance as affected by the use of NAG and OAG concretes, efforts were made to measure early-age CRCP performance indicators such as crack spacing and crack widths. Since the same cement contents and water-cement ratios were used in NAG and OAG concretes, there was little difference in strength-related hardened concrete properties. On the other hand, differences were observed in in-situ COTE and drying shrinkage between NAG and OAG concretes, with lower values for OAG concrete. Even with lower in-situ COTE and drying shrinkage, more cracks formed in OAG concrete than in NAG concrete section, which signifies the effects of other factors such as setting temperatures on cracking behavior of CRCP. It is expected that better long-term performance will be achieved with OAG concrete due to the lower values of COTE and drying shrinkage.