The Research On Microcosmic Action Mechanisms And Road Performances Of Coal Waste Powder Asphalt Mortar

At present,coal still plays an important role in the world energy supply system.But in the process of coal production,coal waste that pollutes the environment was produced.A large amount of coal waste disorderly stacking near coal mines and coal washing plants has caused serious economic and environmental problems.In order to widen the ways of processing and reusing coal waste,explore the application prospect of coal waste used in road engineering,coal waste powder was produced as filler used in asphalt mixtures.The road performances and microscopic action mechanisms of coal waste powder asphalt mortar and mixture were studied in this paper.(1)Under the condition of different filler-asphalt ratios of 0.6,0.8,1.0,1.2,1.4,the coal waste powder(CWP),coal waste ash(CWA),limestone powder(LS),25%CWP+75%LS,50%CWP+50%LS and 75%CWP+25%LS asphalt mortars were researched.The soften point,force ductility,dynamic shear rheology(DSR),bending beam rheological(BBR)and the Brookfield viscosity tests were conducted.The results show that,compared to LS,CWP especially CWA,significantly improves the high temperature stability and temperature sensitivity of asphalt mortar,the low temperature performance is decreased to some extent,and the workability was basically the same.(2)The particle size analysis,scanning electron microscopy(SEM)and X-ray diffraction(XRD)were performed on CWP,CWA and LS.The infrared spectrum(IR)test was performed on the three types of asphalt mortars.The results show that,compared with LS,the particle size of CWP,especially CWA,is smaller,and there are more pore structure and active mineral compositions in CWP and CWA.As a result,they shows different road performances.According to IR test,there was no new functional groups in CWP asphalt mortar.Therefore,the CWP and asphalt are only simple physical cementing.(3)The composition of AC-13 mineral mixture was designed.Then Marshall method was used to design the optimum asphalt-aggregate ratios of AC-13 asphalt mixtures with different fillers.The results show that the optimum asphalt contents of the six kinds of asphalt mixtures are equal to 5.2%,5.2%,5.0%,5.0%,5.1%and 5.2%.(4)The AC-13 asphalt mixtures containing six types of fillers were prepared.Then Rutting test,bending test,splitting test,immersion Marshall test and freeze-thaw split test were carried out on six kinds of asphalt concrete.The results show that,compared with LS asphalt concrete,the performances of rutting resistance in high temperature and water stability of CWP,especially CWA,asphalt concretes are improved to some extent,while the low temperature performance is decreased.