Multi-scale performance study of concrete with recycled aggregate from tannery sludge

In response to China's rapid urbanization and the increasing accumulation of construction waste, it is essential to rationalize waste treatment without damaging the environment. Besides, natural mineral resources such as stone and sand are incredibly scarce. Therefore, it is urgent to find replaceable materials. The main objective of this study is to find a substitute for construction materials obtained by treating industrial tannery sludge harmlessly and effectively to evaluate its application in concrete. This paper explores the physical and mechanical properties of concrete mixed with sludge, and different pores were characterized by Nuclear Magnetic Resonance（NMR）. The result showed that replacing 4 % fine aggregate by sludge will not have significant adverse effect on the properties concrete under the condition that coarse aggregate is 100 % recycled and 10 % cement is replaced by sludge. Industrial sludge substitution for cementitious materials and fine aggregates can alleviate the problem of industrial sludge disposal to a certain extent, which is conducive to sustainable development.