The Research On Properties And Material Mechanical Parameters Of Pinggang Steel Slag Asphalt Mixture

As a big steel country,China produces a large amount of steel slag every year,but the utilization rate of steel slag is only about 30%.In order to solve the redundant waste steel slag,we should actively find ways to consume large quantities of steel slag.In this paper,Pinggang steel slag is used to replace natural stone.The mix proportion design of gradation AC-13,AC-20,and AC-25 is carried out,and its road performance and structural design parameters of steel slag asphalt pavement are studied.The test results provide data support for the popularization and application of steel slag asphalt mixture.1)Taking Pinggang steel slag as the research object,its basic physical and mechanical properties were studied.The chemical composition,mineral composition and microstructure of the steel slag were studied by X-ray fluorescence spectrometer(XRF),X-ray diffraction analysis(XRD)and scanning electron microscope(SEM).The performance tests of limestone,mineral powder,70#road petroleum asphalt and SBS modified asphalt have been carried out,and the test results show that they all meet the requirements of the specification.2)Based on the volume-mass conversion method of aggregates,the mix proportions of three grades of AC-13,AC-20,and AC-25 steel slag asphalt mixtures were designed,and limestone asphalt mixtures of the same grade were set as the control group.Finally,the optimal oil-stone ratios of three graded steel slag-asphalt mixtures of AC-13,AC-20,and AC-25 were determined to be 5.2%,4.7%,and 4.3%,which were 0.4%,0.3%,and 0.2%higher than the control group.3)The road performance of AC-13,AC-20,AC-25 steel slag asphalt mixture and limestone asphalt mixture was studied.The results show that compared with the control group,the steel slag asphalt mixture has better high temperature rutting resistance and water stability.With the increase of the nominal maximum size of the asphalt mixture,the improvement effect of the steel slag on the low temperature performance of the asphalt mixture is weakened.The results of the volume expansion test of steel slag show that the volume expansion rates of the three steel slag asphalt mixtures meet the requirements of the specification.4)Taking AC-13,AC-20,AC-25 graded steel slag asphalt mixture and limestone asphalt mixture as the research objects,the uniaxial compression dynamic modulus test and the uniaxial penetration shear strength test were carried out.The results show that the dynamic modulus of the asphalt mixture increases with the increase of the maximum nominal size of the gradation,and the recommended value range of the dynamic modulus of the steel slag asphalt mixture is given;the ultimate service life of steel slag asphalt pavement and ordinary asphalt pavement are 17 years and 16 years,respectively.The annual construction cost of steel slag asphalt pavement material is 15,973 yuan/year·km lower than that of ordinary asphalt pavement.Steel slag asphalt pavement is more economical and durable.In this paper,the relevant physical and mechanical properties of Pinggang steel slag as coarse aggregate for road use are studied.Therefore,the application of steel slag to asphalt pavement is technically feasible and economical.The research results in this paper can provide a reference for the popularization and application of steel slag.