Experimental Study On Durability And Compressive Strength Of Recycled Concrete

Crushed waste concrete can be adopted as coarse aggregate to produce recycled concrete,which realizes the cyclic utilization of resources.Recycled concrete has advantages on economic and social benefits and accords with the concept of sustainable development.So it has attracted entensive attention and has become research hotspot in recent years.The durability and mechanical properties of recycled concrete has significant deference with ordinary concrete because initial defects would be brought in its waste concrete aggregate during crushing process,which limits its application into construction of reinforced concrete structures in coast and ocean,de-icing salt and other harsh environments.Therefore,this topic aims to study the effect of sodium chloride solution soaking condition on durability and mechanical properties of recycled aggregate concrete.Firstly,specimens of three different water-cement ratios and six different immersion ages are placed into chloride solution to investigate the effect of water-cement ratio and immersion age on durability of recycled aggregate concrete.In addition,some comparative experiments about silica fume between recycled concrete and ordinary concrete are carried out.The results show that chloride diffusion coefficient increases along with water-cement ratio and decreases with immersion age.The impervious performance to chloride of recycled concrete is improved by the incorporation of silica fume and the impervious performance of recycled concrete appears close to that of ordinary concrete.Secondly,the experiment on compressive strength of recycled concrete of three water-cement ratios in six immersion ages are carried out to study on the effect of water-cement ratio and immersion age.Moreover,the compressive strength is also tested through comparative experiment about silica fume between recycled concrete and ordinary concrete.The results show that the compressive strength of recycled concrete increases rapidly in the early stage and slowly in the later stage.And the compressive strength decreases while water-cement ratio increasing.The incorporation of silica fume can effectively improve the compressive strength of recycled concrete.The relative compressive.