Effect of raw material ratio on properties of phosphogypsum- blast furnace slag cold bonded aggregate

Abstract In order to solve the serious environmental problems caused by the storage of phosphogypsum (PG) and alleviate the consumption of natural aggregates such as sand and gravel. PG, blast furnace slag and cement were prepared into round particles of 5–13 mm by disc granulator. The effects of different raw material ratios on the properties of phosphogypsum-slag cold bonded aggregate were studied. Additionally, the physical characteristics and mechanical strength of PBCA were examined across different proportions of PG and blast furnace slag. By elevating the PG content from 60–90%, there was a notable decline in the bulk density of PBCA from 1021 kg/m3 to 953 kg/m3 after 28 d. Additionally, the cylinder compressive strength of PBCA decreased significantly from 16.22 MPa to 1.96 MPa when subjected to dry conditions. Furthermore, the water absorption rate witnessed a notable increase from 6.01–13.41%. MIP analysis showed that with the increase of PG content, the internal pore size of PBCA gradually increased, and the proportion of pores larger than 200 nm increased.