Resource recycling sustainability assessment in ready-mixed concrete manufactured on energy consumption and environmental safety in China.

Abstract

With the rapid development of construction industry, consumption of ready-mixed concrete has increased rapidly in China. As a kind of green building material and waste comprehensive utilization product, industrial solid waste-based ready-mixed concrete have better performance in terms of resource conservation and durability. However, some typical issues are associated with industrial solid waste resource recycling in ready-mixed concrete production process such as energy and material consumption, as well as leaching pollutant emissions. So, a "life cycle assessment" of the particular elements has been carried out, determining the resources consumption of all the processes of the ready-mixed concrete production. Through preparation of several different strength grades of concrete, the embodied energy and resources consumption indicator are quantitative evaluation. In addition, the environmental safety assessment was also proposed. The results show a certain linear relationship of concrete with various strength grade and its resources consumption, the higher strength grade, the more resources consumption potentials in the production of concrete. In this case, the linear correlation coefficient R2=0.98313 between them, and the equivalent coefficient's order of the main resources, is as follows: the first is oil, then natural gas, iron ore, limestone, gypsum, and fly ash, and the last is coal. The more preceding shows more scarcity. Meanwhile, the general leaching of heavy metals Cu, Zn, Ni, Cr, Pb, Cd, and Ba of solid waste-based C20 concrete were also checked out. So, to further ensure the environmental safety, the potential ecological risk method was adopted to assess the heavy metal security and solid waste resource utilization.