A Study On Durability Of Recycled Concrete With Early Strength Agent

With rapid development of Chinese economy and urbanization,a large number of waste concrete is produced because of the removal,reconstruction and reinforcement of old buildings.If the waste concrete is dealt with improperly,serious ecological environmental problems will appear,so will certain damages to our society;if suitable treatment is done,the construction waste can be changed into things of value,which can not only save resources but also can bring about economic benefits.Another dimension,with continuous exploitation of natural resources,they are exhausted day by day.In consideration of the Chinese strategy of sustainable development,the construction waste is also required to have cyclic utilization.Therefore,it is extremely important to study strength and durability of recycled concrete in order to transport it safely to construction site.In this paper,the influence of early strength agent on the strength,frost resistance and permeability of recycled concrete was studied by contrast test.Besides,some achievements are obtained.In this paper,based on three kinds of water binder ratio and different replacement ratio of recycled aggregate,the experiment design of recycled concrete is carried out.Meanwhile,a comparison is made with recycled concrete without adding early strength agent on equal conditions in order to study strength of recycled concrete.Afterwards,the influences of early strength agent,replacement rate of recycled aggregate and glue ratio on strength of recycled concrete are analyzed.In this paper,the frost resistance of prepared recycled concrete is studied..The result shows that early strength agent can improve frost resistance of the concrete;glue ratio and replacement rate of recycled aggregate have important effect on the property.Besides,there is a negative correlation between frost resistance and glue ratio as well as replacement rate of recycled aggregate.That is to say,frost resistance of recycled concrete will be poorer with the increase of glue ratio and replacement rate of recycled aggregate.The impervious performance of prepared recycled concrete is studied in this paper.The result shows that early strength agent can improve the impervious performance of the concrete;There is a negative correlation between replacement rate of recycled aggregate and glue ratio and water permeability resistance of the concrete.