Experimental Study On The Effect Of Waste Plastic Aggregate On The Mechanical Properties Of Cement-stabilized Macadam Mixture

Semi-rigid base layer has many advantages such as high strength,good water stability and good resistance to freezing and thawing,so it has been widely used in our country.But there are many problems in practical application,among which the most prominent one is pavement cracking,and the most problems are related to the base material.On the other hand,considering the shortage of raw materials for construction and the environmental pollution caused by waste plastic treatment,this paper puts forward the idea of replacing coarse aggregate in cement stabilized macadam with plastic aggregate in equal volume,and explores the mechanical properties and toughness of cement stabilized macadam mixed with plastic aggregate,so as to lay a foundation for the research of cement stabilized macadam material modification and the engineering application of plastics.This paper explains the structure composition and strength formation mechanism of cement stabilized macadam,and puts forward an evaluation method for the toughness of cement stabilized macadam.The test sets up six different plastics contents,measures the toughness of cement stabilized macadam by energy method and tension-compression ratio,and completes the compressive strength test,splitting strength test,flexural tensile strength test and toughness test.At the same time,the paper also explores the feasibility of adding plastic aggregate into cement stabilized macadam.The results show that the 7-day compressive strength of the 4%~20% Plastics Group meet the standards.In these specimens maintained for 28 days,compared with the non-plastics group,the volume density,compressive strength,splitting strength and flexural tensile strength of the 4%~20% Plastics Group are reduced by 0.31%~2.22%,5.81%~24.48%,1.27%~22.31% and 4.44%~25.56%,respectively.The displacement change under constant load shows that the deformation ability of the plastics aggregate is better than that of the non-plastics group.The toughness and tension-compression ratio of different plastics content increased firstly and then decreased with the increase of plastics content,reaching the maximum at 16% of plastics content,while the toughness and tension-compression ratio of non-plastics group were the minimum.The above results show that it is feasible to replace coarse aggregate in cement stabilized macadam with plastic aggregate in equal volume.On the one hand,plastic aggregate will reduce the compressive strength,splitting strength and flexural tensile strength of cement stabilized macadam,and the reduction will be greater with more plastic content.On the other hand,plastic aggregate can reduce the volume density of cement stabilized macadam,make it lighter,and improve the deformation ability and toughness of cement stabilized macadam.