Enhancement of impact resistance for low water/binder cementitious composites (LWBCC) based on porous aggregate: From the perspective of macroscopic and microscopic

Abstract

Impact resistance is an important index of durability of concrete materials. As a kind of porous aggregate, pottery sand has the ability to absorb impact energy, which can be used to improve the impact resistance of cement-based composites. This study intends to use macro and micro method to analyze the influence of pottery sand on the impact resistance of low water/binder cementitious composites (LWBCC). Firstly, a series of mix proportions are designed according to the characteristics of each raw material and pottery sand. Then, the compressive strength and impact resistance of the test blocks are tested and the cracks of the test block are further analyzed. The results show that the incorporation of pottery sand can significantly improve the impact resistance of the test blocks. The fractal dimension of the crack pattern shows a decreasing trend after an initial increase with the increase of the pottery sand content. Finally, the micro-structures of pottery sand and river sand LWBCC samples are further analyzed by nanoindentation and SEM. The interfacial transition zone (ITZ) between the LWBCC matrix and pottery sand is proved to be better compared with that between the matrix and river sand. It is established that the incorporation of pottery sand as fine aggregates can effectively improve the impact resistance of concrete materials.