Research On Reusing Construction Waste In Cement Production

Construction waste was generated in the process of building construction,maintenance,demolition, most of that was the solid waste. It included concrete,abandoned brick,asphalt concrete and construction waste scattered mortar and concrete and so on. With the rapid development of the construction industry, the total amount of construction waste increased rapidly, As in recycling construction consuming large energy, it has been limited tin he application of construction waste. Most of the re-used construction waste for general backfill, as the basis for building or road. It occupies land and may cause secondary pollution. In this paper, using concrete, construction waste burning cement clinker as raw materials for the applications reuse construction waste.Separating the waste concrete aggregate from matrix bonding used the methods of heat treatment and mechanical. Obtained substrate heated treatment under different temperature as mixed materials according to different ratio of bonding component, and used in cement. The results show that, The combination of heat and mechanical force can be separated the waste concrete aggregate and matrix bonding component effectively. In the context of 500℃, the higher the heating temperature, the separation efficiency. Waste concrete was separated from the matrix composition can prepare the binding materials with hydration activity. The hydration activity related the burning temperature. When heated to 500℃, The results show that, substrate bonding component was 20 percents, the intensity of the samples'3d,28d near the comparison sample. Hydrated minerals formed well observed by XRD and SEM.Burning cement clinker used construction waste as raw materials, prepared raw materials with construction waste that will be properly handled in the proportion of 10%, 15%, 20%, 25% , fired clinker at 1450℃. In the conventional burning temperature, cement clinker was burned with the components of construction waste as raw materials. The mineral composition of cement clinker the same as ordinary Portland cement observed under XRD and SEM. the appearance of major minerals in the clinker is clear and develop well. The product was observed hydration 3 and 28 days under XRD and SEM. Mineral's formation and morphology was basically the same with ordinary Portland cement. The content of f-CaO each group clinker was less than 1.5%. The raw material prepared construction waste as raw material components has good burnability. The grade of strength can reach the standards of ordinary Portland cement. When the incorporation of construction waste was 20%, the compressive strength of hydration 28 days was 68.4Mpa.The application of activator in the process of burning cement clinker used construction waste as raw material. Because there was some inert of SiO₂ in construction waste. Choose some of the activating agent, find the optimal solution that can increase the activity of SiO₂, by the amount of each activator and the effect of different activators. The results show that, the levels of f-CaO was lower in Clinker, the burnabilitywas well. The content of f-CaO showed a decreasing trend as the dose of activator increased, and showed a growing trend with the alkaline of activator was lower. The minerals were clear in cement clinker. The quality of mineral and mechanical properties was proportional to the amount of activator and the alkaline intensity of activator. The compressive strength is highest when the activator was NaOH and the adding ratio is 2%. And the formation of mineral was best when observed By SEM,XRD,EDS.