Study On The Performance Of Activated Waste Rubber Powder Modified Asphalt And Asphalt Mixture

With the rapid development of automobile industry,the problem of waste tire pollution becomes more and more serious.The main component of waste tire is vulcanized rubber,the cost of desulfurization and reuse the vulcanized rubber is high,and it is difficult to degrade under natural conditions,so the countries are constantly looking for the ways to reuse waste tires.The waste tire rubber powder has the advantages of high thermal insulation and elastic resilience,and can be used as an alternative material or an asphalt modifier in the field of road engineering,which can improve the quality of pavement and prolong the service life.It is hoped that through the research of waste rubber powder modified asphalt,the application of waste rubber powder in asphalt pavement engineering will be expanded,and the environmental pollution caused by waste tire will be reduced.In this paper,the waste tire rubber powder were modified through microwave activation and alkali treatment,and crumb rubber modified asphalt(AR)was prepared,the impact of the powder particle size and dosage on asphalt were analyzed.The three indexes,resilient recovery ability,segregation stability and rheological property of microwave activation rubber powder asphalt,alkali treatment rubber powder asphalt,ordinary rubber powder asphalt and matrix asphalt were tested and compared.The mix ratio design and molding process of crumb rubber modified asphalt mixture were studied,and the road performance of crumb rubber modified asphalt mixture was tested and evaluated,study of crumb rubber modified asphalt mixture ratio design and molding process;and the modified asphalt mixture of crumb rubber road tested and evaluated the performance.Finally,the road performance of crumb rubber modified asphalt mixture was tested by the test section.The penetration index,softening point and ductility of microwave activation rubber powder asphalt,alkali treatment rubber powder asphalt,ordinary rubber powder is higher than the matrix asphalt.When the rubber power in the microwave activated crumb rubber asphalt is 14%,the penetration index is 0.49,the softening point is 58 ?,5? ductility is 19.5cm,with the decrease of the size of the rubber powder,three,the penetration index,softening point and ductility of the three rubber powder modified asphalt were increased.When the rubber power in microwave activated asphalt modified is 80 mesh,the penetration index of the asphalt reach the highest,and the value is 0.68,the softening point is 58.5?,5?ductility is 19.1cm.The elastic recovery ability and the stability of the separation showed that the elastic recovery rate of the alkali treated rubber powder modified asphalt was the largest,and the value is 78%.and the difference of the segregation softening point of microwave absorbing rubber asphalt was the lowest,the value is 1.5%,and the stability was the best.The results of rheological properties show that the storage modulus of the microwave activated crumb rubber asphalt microwave is the largest,the phase angle is the smallest,the rutting factor is the largest,and the rheological properties are the best.Through the analysis of the results of the above four kinds of asphalt,the results show that the temperature sensitivity of the microwave activated rubber powder asphalt is weak,and the rheological property and the segregation stability are better than those of the other three kinds of asphalt.The properties of microwave activated crumb rubber modified asphalt can meet the requirements.Therefore,the microwave activated crumb rubber modified asphalt were used in the mixture.Mixture ratio design of crumb rubber modified asphalt mixture were studied,the discontinuous gradation is beneficial to form a skeleton dense structure,it has enough space to accommodate the elastic waste rubber powder modified asphalt,and enhance the anti deformation ability of mixture.Finally,the discontinuous graded AR-AC13 as the mixture ratio,the optimum asphalt aggregate ratio is 6.36%.based on the index of void ratio(VV),the molding technology of crumb rubber modified asphalt mixture were studied,the effect of compaction times and compaction temperature on the porosity of mixture(VV)were analyzed,the results show that the compaction times and the compaction temperature of crumb rubber modified asphalt mixture are 75 times and 160-170?,which is more appropriate.The high temperature stability,low temperature crack resistance and water stability of the continuous gradation AR-AC13,discontinuous gradation AR-AC13 and continuous gradation of AC-13 mixture were analyzed.The test shows that the waste rubber powder is helpful to improve the pavement performance of asphalt mixture,compared with the continuous gradation AC-13,the road performance of discontinuous graded AR-AC13 has greatly improved,the dynamic stability of discontinuous gradation AR-AC13 is2.67 times of continuous gradation of AC-13,low failure strain increased by 26.33%,TSR index increased from 85.5% to 86.6%.The mechanical property of the continuous gradation AR-AC13,discontinuous gradation AR-AC13 and continuous gradation of AC-13 mixture were analyzed.under the condition of high temperature,the discontinuous gradation of AR-AC13 has the maximum dynamic modulus,andown high elastic deformation capacity,it shows that the discontinuous graded AR-AC13 has better resistance to deformation at high temperature.Quality inspection was carried out on the test section of crumb rubber modified asphalt mixture,The basic performance of the test section can meet the specification.