Laboratory Experimental Study On Regeneration Of Large Amount Of Waste Asphalt Mixture

The test material is the waste asphalt mixture produced by the renovation of Xuanhua section of national highway 112.Through the extraction test of the mixture,the aging of the old asphalt mixture in this section is evaluated.The mixture design and road performance test of recycled asphalt mixture was studied.The economic and environmental benefits of recycled asphalt mixture with large amount of admixture are analyzed.The conclusion is as follows:(1)The content of waste asphalt is 4.06%.Only the softening point meets the requirements of the specification,and the ductility and penetration are far less than the requirements of the specification,which shows that the asphalt aging is serious.Through the screening test of the mineral aggregate in the waste asphalt mixture(RAP material),it is found that the grading curve is near the grading curve of AC-13 mixture,which indicates that the mineral aggregate can still meet the requirements of the road.(2)The amount of asphalt regenerant determined by performance design method is 11%.According to the determination of three major indexes of recycled asphalt,it can be seen that adding recycled agent will lead to the decrease of thermal stability of asphalt.(3)The mixture ratio of recycled asphalt mixture with different rap content was obtained by numerical method.(4)Marshall test was carried out on recycled asphalt mixture with different rap content to obtain the corresponding optimum asphalt content.The results show that the optimal asphalt content first decreases and then increases with the increase of RAP content,the stability first increases and then decreases with the increase of RAP content,and the flow value increases with the increase of RAP content.(5)The road performance test of recycled asphalt mixture with different rap content shows that the increase of rap material will increase the high temperature stability,decrease the water stability and low temperature stability of asphalt mixture.(6)Adding a certain amount of solubilizer can effectively improve the regeneration effect of recycling agent on waste asphalt.According to the test,the reasonable amount of solubilizer is between 10% and 20%.(7)Using recycled asphalt mixture can bring considerable economic and environmental benefits.Taking Xuanhua section of national highway 112 as an example,481 tons of asphalt and 11375 tons of earth rock resources can be saved each year when the waste asphalt mixture is used in the production of recycled asphalt mixture.It is not only conducive to the recycling of resources,but also solves the problem of the damage of asphalt waste to the ecological environment in this area.