Compound Mixing and Properties of Recycled Brick with Construction Spoil

To solve the increasing construction spoil (CS),the feasibility of making recycled brick from CS and compound construction spoil (CCS) from different sources was studied,the grain composition,chemical composition,mineral composition,liquid limit,plastic limit and plastic index of CS were tested,the process of extrusion molding,drying and sintering were observed,and the density,24h water absorption,compressive and flexural strength of recycled bricks were tested,and the micro appearance of recycled brick was observed by SEM.It was found that only few kinds of CS can make recycled bricks directly,however the recycling rate of CS could increase to 100% through compound methods.The particle composition and mineral composition of the CS could be adjusted by compounding,while the clay minerals content of CCS increases,the plasticity also increases,and it is easier to be extruded into shape,but also easier to crack while drying.CS with larger clay mineral content produces more low-eutectic during sintering,which leading the lower porosity,higher density,and higher compressive and flexural strength of recycled brick.The compressive strength of recycled bricks could be improved up to 26.7% through reasonable compounding.Finally,a rapid identification and compounding method of making recycled bricks from CS was established,by testing the liquid limit,plastic index or the particle distribution curve and clay mineral composition of CS,the feasibility of making recycled bricks from CS can be quickly identified,and a reasonable compound design can be calculated.