Study On Utilization Of Crushed Clay Brick From Construction Waste

With the urban construction, renovation and the poor quality level of clay brick production, a large amount of construction waste clay brick is discarded in our country. It not only pollutes the environment, but also occupies land resources. How to use these waste clay bricks effectively is an urgent issue. Crushed clay brick is often overlooked because its mechanical properties is lower than that of the recycled concrete, but the grinding performance of crushed clay brick is good, as its high degree of fine grinding and grinding processing is easy to realize, the available space for utilization of recycled brick powder is greater.This paper analyzes the physical and chemical properties of the recycled brick powder, and studies the influences on cement mortal properties as partial replacement of cement with recycled brick powder, and investigates the activity modification of cement mortar added recycled brick powder according to the compound excitation experiments. Finally, based on the analysis of performance and activity modification effect of recycled brick powder, the non-fired and non autoclaved compression moulding bricks made of recycled brick powder have been produced. The main contents and results are as follows:(1)By comprehensive analysis of the basic physical properties, micro structure and chemical composition of the recycled brick powder, it is concluded that recycled brick powder has great potential as a high quality mineral admixture.(2)The influences on cement and cement mortal properties as partial replacement of cement were studied, including water content for normal consistence, activity index, strength, fluidity and shrinkage performance. It shows the finer the powder the larger water demanded. The highest activity index of recycled brick powder is up to81%. And it is concluded that the regression curve equation between brick powder fineness and activity index. When mixed with recycled brick powder, the shrinkage of cement mortar is reduced, ratio of bending-compressive strength is increased and the ductility is improved.(3)Acording to chemical excitation experiments, the activity modification of recycled brick powder were studied. The results showed that effect of water reducing agent is not obvious when water-cement ratio is0.5, the stimulate effect of calcium chloride and gypsum is good, the reasonable doped amount of sodium silicate ranges from0to1%, the best doped amount of caustic soda is0.8%. With index of28-d compressive strength, the best effect excitation combination reached45.6MPa.(4)The preparation technics of compression moulding brick which is made of recycled brick powder were studied. According to several trials comparing, when the molding pressure is20MPa, water consumption range14%to18%, the effect is good.(5)The compressive and flexural properties of compression moulding brick in the case of different mix proportions were studied. Compressive strength of the best set is up to34.98MPa and flexural strength is6.36MPa.(6)The high temperature resistant and fireproof performances of the compression moulding brick were studied. The strength and mass loss of specimens at600℃and1000℃high temperature were tested respectively, and the results showed that recycled brick powder compression moulding brick have good high temperature resistant and fireproof performance.