Rearch On Environmental Burden Of Concrete And Disposal Optimization Of Waste Concrete Based On LCA

With the accelerating development of urbanization, the resources and environmental issues have been arousing big concerns. As the basis of the main industry, construction needs large quantities concrete which consumes a large amount of resources and energy during its production and usage, and vast construction waste concrete increase sharply. According to the related research, the amount of waste concrete will reach 3.811 billion tons in 2020 in China.In this thesis, the concrete was chosen as the research object, the relevant data of concrete and cement in Beijing were collected and the life cycle environmental impacts were quantitatively analylized including its production, transportation, use, removal and disposal. The results showed the environmental impacts of various grade concretes in their production processes were diffierent with the values increase by the order as C100 > C80 > C60 > C50 > C40 > C30. The reason was the raw materials input in the various grade concrete increased. Among the chosen environmental impact categories, the RI of the concrete production and the use stage was the largest, which is mainly resulted from the mining and processing of raw materials and concrete mixing. The RI of 1m3 concrete of C30 was 1.53 kg PM2.5 eq during its whole life cycle while the RI at its production stage, use, the landfill and transport were 0.38 kg, 1.05 kg, 0.09 kg, 1.13 x 10-5 kgPM2.5eq, respectively. The RI in the whole life cycle of concrete mainly came from the concrete production stage and using stage, which accounted for about 25% and 69%, respectively. On the basis of the obtained results of concrete environmental impact assessment, analysis of the main environmental problems and its influencing factors of the various stages of the life cycle of concrete, the effective and positive suggention was put forwarded in order to reduce the resource consumption, improve the energy effiency and protect environment in the concrete production activities.Then, in order to make a optimization selection of disposal the waste concrete among three methods of the direct landfill, the basic packing and recycled aggregate, an optimal analysis model for disposal the waste concrete was established based on the actual conditions of Beijing. Comprehensively considerring environmental costs and economic input and based on the theory of life cycle assessment and social willingness to pay, the model explored the method to quantitatively evaluate the environmental impact of environmental costs using the social willingness to pay. Then the economic input of three ways to deal with the waste concrete were quantitatively analyzed on the basis of the given environmental costs, demolition cost, transport cost, disposal cost and market factors. The results showed the method of the recycled aggregates when disposal of C30 waste concrete was benefit for the environment, and the value of environmental costs was 10.2 yuan/m3; In terms of economic input, the results showed that the cost of the basic packing was the least with a value of 126.32 yuan/m3, but the method was obviousy limited by the space and materials because only a little of waste concrete ban be the basic pacing. The economic input of recycled aggregate was the most with a value of 208.18 yuan/m3; Comprehensively considering environmental costs and economic input and at the actual situations of Beijing, the recycled aggregates way for disposal the waste concrete was the optimal with a value of 197.98 yuan/m3.At the end, on the basis of the resluts above, the corresponding measures and suggestions in management system, production technology to industrial chain have been put forwarded in order to promote the resource recycling waste concrete in Beijing.