Effects of Nanomaterials Reinforced Aggregate on Mechanical Properties and Microstructure of Recycled Brick Aggregate Concrete

In this paper, the effects of nano-SiO2 and nano-Al2O3 on the brick aggregate properties, compressive strength of brick aggregate concrete at different ages, and microstructure of brick aggregate concrete are investigated. The results show that the water absorption of recycled brick aggregate decreases with the increase of nanomaterials solution concentrations, and the crush index of recycled brick aggregate decreases. Nano-SiO2 and nano-Al2O3 improve the compressive strength of recycled brick aggregate concrete at different ages, and the effect of nanomaterials on the early strength of concrete are more obvious. With the increase of nano-solution concentration, the compressive strength of nano-SiO2 reinforced brick aggregate concrete increases first and then decreases, while that of nano-Al2O3 reinforced brick aggregate concrete increases. The internal structure of nanomaterials reinforced brick aggregate is denser, micro cracks and pores are filled with hydration products, and the interfacial transition zone is more compact.