Utilization of concrete slurry waste for soil stabilization

The stabilization of clay soils is one of the crucial problems of engineering, because it determines the long-term stability and operability of structures, especially in case of infrastructure. Present work is focused on the experimental investigation of the utilization of concrete slurry waste (CSW), which is generated during ready-mix concrete production, as a stabilizing agent of clay soil. The alkaline character and content of cement residues in the studied waste material provide suitable potential for the proposed application. The contribution of CSW to soil stabilization was investigated in terms of compressive strength, the California bearing ratio (CBR) and Immediate bearing index (IBI). The nature of the stabilization process was documented by scanning electron microscopy (SEM) and monitored by thermal analysis and X-ray powder diffraction (XRD). The performed experimental program was organized as benchmark test to express the stabilizing properties of CSW in comparison to ordinary Portland cement (OPC). The studied CSW contributes to soil stabilization by the calcium ion exchange, what was documented by IBI, and by the formation of hydraulic products. The studied CSW attained a stabilizing effect by 38% than with the same dose of OPC in terms of compressive strength. The studied waste material has great potential to achieve economic and environmental savings, if applied to soil stabilization.