Filling performance of self-protecting underwater mortar via aggregate interstices in the water environment

Although numerous studies have explored the performance of mortar with aggregates, research into the principles governing the filling of mortar in aggregate interstices in water environments, as well as strategies for effective filling, remains limited. This study investigates the effects of several factors on the filling of aggregate interstices by mortar, including the pouring environment, aggregate size, flowability, and maximum particle size of sand. Additionally, it examines the relationship between concrete porosity and strength at both the macroscopic and microscopic levels across different environments, namely air and water. The findings indicate that a reduction in the aperture ratio (Dr) increases the likelihood of granular blocking, thereby reducing the efficiency of mortar filling. Moreover, compared to the air environment, in the water environment, the reduction in pressure differential slightly decreases the mortar filling capability, which in turn leads to a higher porosity in the concrete, manifesting as lower compressive strength of the concrete. Furthermore, a formula has been derived to accurately forecast the outcomes of mortar filling within aggregate interstices.