Research On Effects Of Nano-ZnO On Anti-Aging Performence Of Ethylene Propylene Diene Monomer Modified Asphalt And Its Mixture

Rubber asphalt has good resistence to low temperature,so it is widely used for road construction in cold area.However,rubber asphalt will age during long-term use,Aging will cause pits,looseness and other diseases on the asphalt road.It will also seriously deteriorate the low temperature performance of rubber asphalt pavement,resulting in low temperature cracks on the pavement.Nano-ZnO has a strong ability to shield ultraviolet light,it can also improve the thermal aging resistance of asphalt to a certain extent.Nano-ZnO is used to modify EPDM asphalt to improve its anti-aging properties and extend its service life.Firstly,test and analyze will be carried on the raw materials to obtain the technical indicators of the raw materials.The composite modified asphalt will be prepared by blending,and the effect of nano-ZnO on the performance of EPDM asphalt will be studied through asphalt segregation test,bitumen penetration system tset and dynamic shear rheological test.The results show that the addition of nano-ZnO improves the thermal storage stability and high-low temperature performance of the modified asphalt,and its resistance to deformation is also enhanced.Secondly,according to the aging scheme,the composite modified asphalt with different EPDM and Nano-ZnO content is subjected to short-term aging and long-term UV aging,and the performance test of the aging residue is performed.The effect of the blending dosage of the two modifiers on the anti-aging performance of the composite modified asphalt will be studied to determine the reasonable blending dosage of the modifiers.The results show that the incorporation of Nano-ZnO improves the thermal aging resistance of asphalt to a certain extent.It can obviously improve the anti-ultraviolet aging ability of the modified asphalt,but its improvement effect will weaken with the extension of ultraviolet aging time.the composite modified asphalt has the best anti-aging performance when the Nano-ZnO content is 3%.The change of EPDM content has little effect on the aging resistance of modified asphalt.Finally,the effects of Nano-ZnO on the anti-aging properties of the composite modified asphalt mixture will be studied by conducting low-temperature bending test,immersed Marshall test and freeze-thaw splitting test on the unaged and aged asphalt mixture.The results show that,compared with EPDM asphalt mixture,the composite modified asphalt mixture has a smaller change in tensile strength,strain value,and bending stiffness modulus after aging,;the residual stability ratio and freeze-thaw spliting strength ratio of the composite modified asphalt mixture are higher than that of EPDM asphalt mixture,and their change rate is relatively small after aging.