Stabilization/solidification of sand-washing slurry used for porous cold-bonded ceramsite

Solid waste is considered a promising resource to manufacture environment-friendly building materials. A huge amount of sand-washing slurry is generally generated from construction sites and plants, and its improper accumulation can pose a major threat to the ecology and the environment. To reuse this sand-washing slurry, a porous cold-bonded ceramsite was prepared using a foaming agent based on crushing technology. The influences of the sand-washing slurry content and the foaming agent content on the engineering properties of ceramsite were investigated. The microstructure of ceramsite was analyzed by scanning electron microscopy, and its crystal structure was revealed by X-ray diffraction. In addition, the inner structure of ceramsite was explored by X-ray computed tomography. The sample with a sand-washing slurry content of 70% and a foaming agent content of 15% exhibited the lowest strength, indicating that the sample with higher water absorption capacity and porosity had lower compressive strength. As an excessive amount of sand-washing slurry could decrease the mechanical properties of ceramsite, a proper mixing proportion is required to produce ceramsite. These results suggest that there is potential in using sand-washing slurry to develop a porous structure light-weight aggregate. This ceramsite could potentially be applied in landscaping and agriculture.