Properties of waste brick powder-based artificial fine aggregate and its application in concrete

Shortage of natural fine aggregates (NFAs) and large amounts of construction solid waste have become prominent issues in the construction industry. To deal with these problems, this study aims to utilize waste brick power (WBP) to develop WBP-based artificial fine aggregates (AFAs) by high-speed stirring method. In this study, the effects of different proportions of WBP, waste concrete powder (WCP), fly ash (FA), slag powder (SP), calcium hydroxide (Ca(OH)2) and ordinary Portland cement (OPC) on the mechanism, physical and microscopic properties of AFAs were analyzed. Besides, the mechanical properties of concrete using COM AFAs (i.e. the AFAs containing all aforementioned powders) were measured. The results showed the single particle compressive strengths (SPCSs) of WBP-based AFAs increased with the increasing OPC, SP, FA or Ca(OH)2 contents. The WCP contents had a slight effect on the SPCSs. Compared with the NFAs and recycled fine aggregates (RFAs), the apparent density, the loose and close bulk density of COM AFAs reduced, and the loose and close bulk voidages increased. However, the water absorptions of COM AFAs were larger than NFAs, but less than RFAs. It was due to the generation of hydration products during the preparation of AFAs that filled the pores of AFAs. In addition, it was found that the cubic compressive strength and splitting tensile strength of COM AFA concrete using COM AFAs with 20 % OPC content were larger than those of concrete using NFAs and RFAs and COM AFAs with 10 % OPC content.