Study On Compaction Property Of Rubber Asphalt Mixture

Rubber asphalt is a kind of asphalt cement which is made up of crumb rubber and asphalt that have fully swelling reaction at high temperature,the incomplete dissolved rubber particles play a rather complicated role in asphalt and asphalt mixture and still will swell during the process of rolling into shape.Compared with other asphalt mixtures,rubber asphalt mixture boasts low modulus and large rebound deformation,therefore,compaction control becomes the key of quality control of rubber asphalt pavement.In this way,it is significant to focus on the studies of influence factors of compaction capacity of rubber asphalt mixture.First,this thesis focuses on the gradation composition design of rubber asphalt mixture.Based on the methods of gradation design and the tests on raw materials,several mixture gradation curves are drawn up.Moreover,employing Marshall compaction method,in combination with the test results of the high-and low-temperature capacity of mixture,the thesis gets that when the passing rate of sieve pore of 4.75 mm controlled by gradation composition is between 30%and 35%,the rubber asphalt mixture has better comprehensive capacity.Next,it studies on the properties of aggregate.According to the studies employing Marshall compaction method and gyratory compaction method,the content of acicular particles of aggregate will affect its mechanical property and the forming of mixture during the compaction;the more coarse aggregate indicates the poorer compactibility,which has deeper influence even than the apparent viscosity of asphalt.Based on the gyratory compaction test on mixtures prepared with rubber asphalt of different viscosities and different powder fineness,the rubber asphalt mixture should be compacted under high temperature but not excessively high.It is suggested to control the initial temperature between 180℃ and 185℃.Finally,the thesis lays emphasis on the construction of test road.At the construction site,thermal infrared imager is employed to monitor the temperature during the compaction process of asphalt rubber pavement,in this way,we get that the paving temperature has great influence on the compaction effect of pavement and the variation of mixture temperature mainly happens in the earlier and later phases of skip unloading.It is recommended that the road roller should increase the times of compaction and shorten the distance of initial compaction within two to three minutes after mixture unloading and suitably increase compaction distance in the medium phase of unloading.