Experimental investigation on the properties of the interface between RCC layers subjected to early-age frost damage

Abstract

This research presents the macroscopic and microscopic performance of the early-age frost roller compacted concrete (RCC) interface to investigate the influence of pre-curing time and interval time on the performance of the RCC interface subjected to early-age frost damage. Therefore, several RCC specimens were developed under different pre-curing times (12 h, 24 h, 48 h, 72 h and 7 d) and different interval times (4, 12 and 24 h). The shear failure modes, shear strength, pore structure, interfacial transition zone crack width (Wc) and hydration products of the RCC interface were evaluated. Results reveal that the shear strength of early-age frost RCC interface increases with the increase in pre-curing time and decreases with the increase in interval time. In particular, the decrease in shear strength of the early-age frost RCC interface is the most critical after the final setting. The decrease in shear strength between the initial setting and the final setting follows. Moreover, the decrease in shear strength before the initial setting is minimal. The relationship between the macroscopic and microscopic performances of the RCC interface that suffered early-age frost damage was established: the shear strength increases with the decrease in porosity and Wc. Hydrostatic pressure increases are the leading cause of damage in the early-age frost RCC interface. Moreover, the early-age frost RCC interface exhibits higher porosity and Wc and fewer hydration products than the unfrozen RCC interface. Finally, a shear strength of early-age frost RCC was proposed based on the experimental results.