Study On Grading Standard Of Waste Concrete Recycled Coarse Aggregate After Performance Test And Intensified Treatment

With the development of the economy and the prosperity of the construction industry,a lot of waste concrete is produced every year in the world,their handling and stacking not only occupy the land,pollute the environment,but also cause huge economic losses.Therefore,it is urgent to solve the problem of waste concrete.Recycled coarse aggregate can make the most reasonable and efficient use of waste concrete,Save the land occupied by the dumping of construction waste,improve the added value of construction waste resource utilization.At the same time,recycling of these waste concrete has also greatly reduced the consumption of natural resources and the consumption of resources and energy in the process of mining and transportation of natural resources.In addition,the random stacking of waste concrete has caused many traffic accidents,and the safety of people's lives has been affected,and people's normal life has been affected.However,because there is no standard recycled coarse aggregate classification method,recycled coarse aggregate is difficult to be applied to practical engineering,and its utilization rate is very low.This paper is aimed at the extensive characteristics of waste concrete sources,the purpose is to enhance the classification of strengthening regenerated coarse aggregate,Recycled coarse aggregate and strengthening recycled coarse aggregate were studied for the physical properties,working properties and mechanical properties.According to the test methods of natural aggregate,the properties of recycled coarse aggregate and strengthening recycled coarse aggregate including particle gradation,water absorption,apparent density,crushing index value etc were tested.The difference between the basic properties of the recycled coarse aggregate and the recycled coarse aggregate is analyzed and compared.It is found that the basic index performance of recycled coarse aggregate is not significantly different from that of strengthening recycled coarse aggregate,and has a great relationship with the source of raw concrete.At the same time,the reference literature is used,and the water absorption and crushing index are used as the technical index for evaluating the regenerated coarse aggregate.Under the condition of the mixture ratio of raw concrete C30,recycled coarse aggregate with different chemical solutions is used to replace recycled aggregate concrete with 40%,70% and 100% replacement rates,and the effects of reinforced recycled coarse aggregate and recycled coarse aggregate on the performance and mechanical properties of recycled concrete are studied respectively.It is found that the performance and mechanical properties of recycled coarse aggregate concrete are less than those of recycled concrete.On the basis of reference to the classification method of recycled coarse aggregate at home,combined with the actual situation of strengthening recycled coarse aggregate in China,comprehensive analysis of this test data,it is proposed that for the low strength recycled concrete under the substitution rate of less than 70%,it is suggested that the classification index of recycled coarse aggregate strengthened by chemical solution in China take the water absorption rate and crushing index as the main index,and the service life and impurity are used as the secondary classification index.