Lightweight Aggregate Made From Waste Residue Of Construction,Reclamation Of Waste Foundry Sand Dust And Sludge

In recent years,with the reform of the wall materials, building energy conservation and the development of high-rise building, Lightweight Aggregate and it's products have developed quite rapidly, which have a excellent performance(low density, high strength, heat insulation, heat resistant, frost-hardy, and strong anti-seismic performance),adaptability, energy-saving effect is remarkable, and have a better economic and social benefit, so it is widely used in building materials industry.In this paper, on the basis of analyzing the chemical composition of waste residue of construction,reclamation of waste foundry sand dust and sludge, it shows that the suitable chemical composition of raw material is similar to the clay raw materials, so it can be used as main raw material for sintering Lightweight Aggregate.According to the composition of raw materials, determined the suitable ratio of raw materials for sintering Lightweight Aggregate by the single factor test and orthogonal test. By the greast difference analyses and analysis of variance of orthogonal experiments, it shows that the suitable ratio of raw materials for sintering Lightweight Aggregate is waste residue of construction of 50%～80%, reclamation of waste foundry sand dust of 10%～28%and sludge of 10%～22%.In the conditions of suitable ratio of raw materials, the best sintering Lightweight Aggregate parameter have been confined throught studing the effects of forming pressure and sintering system on the properties of lightweighe aggregate, the results showed that the optimum conditions for sintering high-strength lightweighe aggregate is forming pressure of 6 MPa, preheating temperature of 350℃,preheating time of 15min, sintering temperature at 1140℃and sintering time of 20 min, and the properties of production satisfy the national standard GB 17431.1-1998.By adopting SEM, XRD and TG-DTA etc, combining the result of macrostructure and micmstrueture performance of the Lightweight Aggregate, preliminary analysis the formation mechanism of sintering the lightweight aggregate. And detect the Lightweight Aggregate products'leaching rate of heavy metals, the results show that the Lightweight Aggregate products can be used as building material and it will not cause secondary pollution to the environment.Preliminary study use the Lightweight Aggregate as the principal material which obtained from this experiment making for Lightweight Aggregate concrete, it shows the properties of Lightweight Aggregate concrete satisfy the requirements of LC25 of industry standard JSJ 51-2002, and which used in engineering can achieve a better economic, social and environmental benefits.