Mechanical properties and microscopic mechanism of solid waste based binder solidified stone waste

Abstract

The stone waste generated by stone industry occupy land resources, cause safety hazards and need to be efficiently resourcefully utilized. In this study, the CGF solid waste based binder (abbreviated as CGF) with calcium carbide residue (CCR), ground granulated blast furnace slag (GGBS), and fly ash (FA) as components was developed to solidify the stone waste. Through “treating waste with waste”, the resource utilization of solid waste was realized. The mechanical properties and reaction mechanism of CGF solidified stone waste were investigated through unconfined compressive strength (UCS), XRD, and SEM–EDS tests. The results show that CGF has the better solidify effect on stone waste, and its strength meets the requirements of the road base material standards. Compared to cement, the CGF solidified stone waste existed higher UCS at both 7 and 28 d of curing. The UCS of CGF solidified stone waste reaches 2.93 and 4.42 MPa under curing of 7 and 28 d at 5% binder content, which is 1.61 and 1.37 times higher that of P.O. 42.5 cement. Furthermore, the primary mineral-based stone wastes will not react with the binder, and the CGF generates gelling products such as C-S–H C-A-H, and C-A-S–H through alkali-activated reactions between the components of CGF. These gelling products enhance the UCS of solidified stone wastes through cementing and filling effects. The findings provide a feasible approach with low-carbon emission and low-cost for resourceful utilization of stone wastes.