Study On The Properties Of APAO And EVA Compound Modified Asphalt And Its Mixture

The compound modified asphalt usually adopts two or more modifiers to modify the asphalt,which can complement the perf ormance of modifiers and make the performance of asphalt more comprehensive.As an amorphous structure thermoplastic resin material obtained by the copolymerization of ethylene and vinyl acetate monomer,EVA has good compatibility with asphalt and has a go od effect on improving its high and low temperature performance.Moreover,EVA can be recycled from waste plastics,which can effectively reduce the waste of resources and reduce environmental pressure.However,Under the condition of high temperature,EVA modified asphalt is easy to separate from asphalt,and its elastic recovery ability is poor,which easily leads to rutting on the road surface.As a low molecular amorphous plastic material,APAO not only has good high temperature stability and elastic recovery ability,but also has a good effect on the low temperature performance of asphalt.Based on the properties of the above two modifiers,this study proposes that EVA and APAO are jointly used to modify the asphalt,to prepare the composite modified asphalt with the advantages of both,and to be used in the mixture research.The main contents of this paper are as follows:Firstly,through the routine three indicators test,elastic recovery test,rheological test,segregation test and aging performance test,to explore the effect of changing the name of the modifier,to determine the optimal dosage.The results showed that the addition of EVA and APAO enhanced the high and low temperature performance of asphalt.The addition of APAO improves the storage stability and aging resistance of asphalt.However,when the mixing amount of APAO and EVA is too high,the improvement effect is not obvious.Considering the modification effect and economic benefits of the modifier,it is recommended that the dosage of APAO should not exceed6%,and that of EVA should be 2%.Secondly,Fourier infrared spectrometer was used to analyze the changes of functional groups and their chemical composition of asphalt before and after the modification of APAO/EVA composite modified asphalt,and the mechanism of action of APAO,EVA and asphalt.The results showed that two new fronts of 739cm^-1 and968cm^-1 were generated after APAO was added with asphalt,and two new fronts of1243cm^-1 and 1740cm^-1 were generated after EVA was added with asphalt,and these four new fronts could be found in the composite modified asphalt.This indicates that after the addition of APAO and EVA to the asphalt,the chemical reaction between the additives and the asphalt occurred,and new functional groups were generated,which made the structure of the composite modified asphalt more stable.Finally,two kinds of asphalt with excellent performance were selected from the asphalt test results:6%APAO+2%EVA and 4%APAO+2%EVA.The asphalt mixture was tested and compared with SBS,70#and"6%APAO".High and low temperature.The results showed that the high temperature stability,water stability,fatigue performance and energy of APAO/EVA modified asphalt mixture were significantly improved,and the resilience modulus and anti-aging performance of SBS modified asphalt mixture were far better than that of SBS modified asphalt mixture.In terms of low temperature performance,compared with SBS modified asphalt mixture,the strain value was increased,the stiffness modulus was reduced,and the low temperature performance was improved obviously.After comprehensive performance comparison,it is found that the performance of 6%APAO+2%EVA is more outstanding and more suitable for road pavement.