Effect of filler type and content on mechanical properties and microstructure of sand concrete made with superfine waste sand.

Highlights • The optimal filler/sand ratios of sand concrete using GGBS and FA fillers are 0.13 and 0.11 respectively. • The mechanical properties of sand concrete increase and then decrease with filler content increasing. • Sand concrete made with superfine waste sand presents an excellent abrasion resistance. • Sand concrete with the GGBS filler has higher amount of hydrate products and lower porosity than that with FA. Abstract In this paper, superfine waste sand generated in waterway regulation engineering was used as the main raw material to produce sand concrete. The effects of ground granulated blast-furnace slag (GGBS) and fly ash (FA) on the mechanical properties, abrasion resistance, and microstructure of sand concrete were measured and compared. The results show that the mechanical properties of sand concrete increase and then decrease with increasing filler content. The optimal filler/sand (F/S) ratios of sand concrete using GGBS and FA fillers are 0.13 and 0.11, respectively. With 300 kg/m3 of cement content, the incorporation of 200 kg/m3 and 150 kg/m3 of GGBS and FA filler, respectively, results in maximum compressive strengths of 36.1 MPa and 30.5 MPa, respectively, at 28 days, and the corresponding splitting tensile strengths are 3.03 MPa and 2.15 MPa, respectively. This optimum mix with weight losses of 6.58% and 8.01% for GGBS and FA fillers, respectively, presents an excellent abrasion resistance. Furthermore, the test results of scanning electron microscopy and mercury intrusion porosimeter indicate that sand concrete with the GGBS filler has higher amount of hydrate products and lower porosity than that with FA. These findings verify the potential usage of sand concrete made with superfine waste sand as a substitute for ordinary concrete in local hydraulic engineering. [ABSTRACT FROM AUTHOR]