Preparation Study Of Construction Waste Slurry Backfill Material

As the circular economy theory saying, “garbage is the resource that put in the wrong place”. The construction waste can be used as other materials filling after crushed, so it is still a resource which has potential value. Lack of construction waste disposal of the construction waste processing technology to effectively open-air stacking or landfill method of original state,not only make a large number of cultivated land in long-term occupation, but also do harm to the rivers, water, soil and vegetation.Plasma volume expansion of filling materials, which use fly ash, building waste powder,slag, red mud solid waste as base material, cement, gypsum, lime and so on accessories to make a new filling materials. The research of plasma volume expansion filling materials technology which use construction waste, the main goal is to transfer construction waste slurry expansion to filling materials, combine construction waste with filling mining, they both benefit each other. This not only solves the increasingly serious problem of construction waste,but also filling the mining goaf, ensure mining safety, and avoid damage to the ecological environment.We made a feasibility analysis about the preparation of the construction waste slurry body filling materials. Through experiments, we discussed the optimum technological parameters.When the construction waste expansion material filling slurry concentration was 55%, it could ensure the slurry with a certain degree of mobility, and no bleeding and segregation. The content of cement and lime restrict each other, the incorporation of excess lime, caused by high concentration of sodium hydroxide slurry, reduce the system of liquid phase concentration of Ca2+, liquid Ca(OH)2 reduction will restrict the hydration reaction of the cement. In the end,cement and lime content was 20%, 5%. Based on the subject before the study, we had achieved the optimal ratio of accessories which was 12%.In order to ensure the feasibility of construction waste slurry base expansion filling material in mine filling, we made a research about the optimum formulation prepared filling specimens, including the slurry viscosity, filling body strength, rheology, anti carbonization ability. The test shows that the performance of construction waste slurry body filling materials was excellent, meet the needs of underground filling.We used XRD, SEM, TG-DSG and so as to observe the hydration products of construction waste slurry backfill material. we found that the early hydration products wasettringite, the later period was silicon-aluminum gel. According to the hydrating theories of cement, lime, gypsum, the cementing mechanism of construction waste slurry backfill material was due to the instability of vitreous structure material of Ca O-Si O2-Al2O3 system was broken,chemical bond of Si-O, Al-O is fractured,. By erosion,the surface of the particles dissolve,Construction waste powder and supplementary material carried on the hydration reaction,and generate ettringite and gel material, so as to support the internal structure of the filling body.