The Experimental Study On The Bond Behaviour Between Steel Bar And Recycled Concrete After Freezing And Thawing

With the rapid development of the construction, the demand for concrete rapidly increase, which make the coarse as raw material for concrete insufficient. At the same time, environmental problems have become a serious problem with the increase of construction waste. So, Waste concrete can be made of recycled aggregate concrete again as a kind of renewable resources,which can reduce natural sand mining in order to avoid resource exhaustion and reduce the pollution of the environment.It is important to study the durability of recycled concrete that involves resistance to freeze-thaw, chloride corrosion and so on. Several deterioration mechanisms may coexist in all erosive environment actually.Therefore,it is necessary to study the properties of concrete subjected to multiple deterioration mechanisms. In the north cold regions of China,the marine concrete structures are both suffering from the frost and seawater erosion. the frost resistance and mechanic performance of recycled concrete and the bond behavior between recycled concrete and steel bar will be destroyed after freezing and thawing. It is very important for concrete structure to research the bond behavior between recycled concrete and steel bar after freezing and thawing. This paper mainly studies frost resistance and the bond behavior between recycle aggregate concrete and steel bar, referring to the research result to recycled concrete.(1) The mechanical property of recycled aggregate concrete after 0、25、50、75、100 freeze-thaw cycles in water and 3.5 % Na Cl solution are tested in this paper,using the replacement percent of 30%、60%、100%. The influence of freeze-thaw cycles to mass loss and the change of the relative dynamic elastic modulus of concrete are investigated. Study on the influence of recycled coarse aggregate replacement rate on the frost resistance properties of recycled concrete.(2) The experiment study of the influence of freeze-thaw cycles in freshwater and in 3.5 % sodium chloride solution to the bond behavior between recycled concrete with 60% recycled aggregate replacement ratio and steel bar with different diameters.