Experimental Study On The Mechanics And Frost Resistance Of Rubber Recycled Concrete

Improper methods of waste disposal,such as construction waste landfills,have had a significant negative impact on the ecological environment.Recycling construction waste and using recycled aggregate to prepare recycled concrete can not only reduce economic costs but also alleviate resource consumption,which has good economic and ecological benefits.In view of the current situation that recycled concrete is difficult to popularize and apply in cold areas in northern China,adding an appropriate amount of waste rubber aggregate to recycled concrete can significantly improve the frost resistance of concrete,reduce the impact of waste rubber on the environment,and improve the recovery rate of resources.In this paper,rubber powder with particle size of 100 mesh is selected to prepare concrete specimens with rubber powder contents of 0%,2.5%,and 5% and recycled coarse aggregate contents of 0%,30%,50%,and 70%,respectively,and the properties,mechanical properties,and frost resistance of the rubber recycled concrete mixture are studied.The life cycle assessment method is used to analyze the carbon emissions of rubber recycled concrete in its whole life cycle.The main research contents and conclusions are as follows:(1)The performance of a rubber recycled concrete mixture is studied experimentally.The results show that with the increased rubber powder content,the slump and air content of recycled concrete decreased and increased,respectively.When the content of recycled coarse aggregate increases from 30% to 70%,compared with recycled concrete mixed with 2.5%rubber powder,the slump of recycled concrete mixed with 5% rubber powder decreases by16.7%-21.2%,and the air content increases by 22.9%-25.0%.(2)The mechanical properties of rubber recycled concrete are studied experimentally.The results show that the mechanical properties of recycled concrete show a downward trend with the increase in rubber powder content.Based on the content of rubber aggregate,recycled coarse aggregate,and rubber recycled concrete strength reduction coefficient,the compressive strength calculation model of rubber recycled concrete is established.At the same time,the relationship model between elastic modulus and compressive strength of rubber recycled concrete is established.(3)Through the frost resistance test of rubber recycled concrete,the damage change law of concrete with different contents of rubber powder and recycled aggregate is studied.The freeze-thaw damage model of rubber recycled concrete is established and its life is predicted.The test results show that when the selection range of recycled coarse aggregate is less than50%,the recycled concrete has good frost resistance when adding 2.5%.(4)The carbon emissions of rubber recycled concrete in its whole life cycle are studied.The results show that the carbon emission of recycled concrete mixed with rubber powder is lower than that of ordinary concrete,and the preparation of rubber recycled concrete has low carbon potential.Through the curve fitting of data,the relationship between the compressive strength of rubber recycled concrete and carbon emissions in the whole life cycle is established.