The durability of the repaired patch is a complex issue and its performance is affected by workability of the repair concrete in its fresh state, temperature at time of placement, early age compressive strength and bond development, cracking susceptibility (dimensional stability) and resistance to freeze-thaw cycles. In addition, it is also affected by external factors such as, usage of deicer salts and magnitude of the traffic load. The focus of this project was on identifying critical properties that control long-term performance of repair concretes, especially rapid-setting commercial materials extended using pea gravel (nominal size aggregate 9.5 mm). Extensive literature review indicated that the current ASTM C 928 requirements fall short with respect to specifying performance criteria for key parameters that influence the durability of the repaired systems. This paper presents results and analysis of laboratory investigation of four commercial rapid-setting materials (CRSMs). Both fresh (slump flow, setting time) and hardened (compressive strength, slant shear bond strength, cracking susceptibility, drying shrinkage and resistance to freeze-thaw cycles) properties were evaluated. It was observed that measurement of flowability was critical for the assessment of workability of repair concrete. The investigation also showed that many of the available CRSMs do not have sufficient freezing and thawing resistance.
Abstract