Study On Construction Temperature And Test Parameters Of Rubber Powder Asphalt Mixture With High Viscosity And High Elasticity

The tendency of heavy load of vehicles becomes increasingly obvious a amid the development of China’s economy and transportation,leading to relatively low adaptability of ordinary asphalt pavement to current traffic situation.As a result,it is necessary to select the rubber powder asphalt with high viscosity and elasticity to improve the road performance of asphalt mixture.According to the study,the asphalt mixture with high viscosity elasticity enjoys excellent road performance,yet reasonable construction temperature is the key premise.The asphalt is easy to age if the construction temperature is too high,and low construction temperature cannot bring the asphalt mixture into full play.But,at present,the construction temperature is not determined directly in accordance with the "viscosity-temperature" curve of asphalt mixture,but mainly according to the corresponding curve of asphalt.For matrix asphalt,the temperature obtained by this method is in a reasonable range.For modified bitumen,the temperature is usually too high.Therefore,this paper analyzed the method of using mixing power of mixing machine to determine the construction temperature of rubber powder high viscosity high elastic asphalt,and studied the test parameters of mixing machine.In this paper,the reaction mechanism,dry process and wet process of rubber powder high viscosity and high elastic asphalt are analyzed.The road performance of AC rubber powder with high viscosity and high elasticity asphalt mixture was studied by Marshall test.Analysis of viscosity-temperature curve is used to determine the powder of the construction of high viscous elastic asphalt temperature deficiency.This study found through the correlation between the rheological equation of the Bingham model and the mixing power model of the asphalt mixture,establish the viscosity of asphalt mixture mixing model based on power.The equivalent mixing power method is used to determine the powder high viscous elastic best construction temperature of asphalt mixture.In order to meet the test requirements,the mixer was improved.Based on the vertical shaft mixer,a frequency conversion speed regulating device was added and a power testing system was built.EDEM simulation software was used to simulate the change of asphalt mixture uniformity in the mixing cylinder.It was determined that the filling rate of the improved mixer should not be less than 50%,and the reasonable speed should be200deg/s～250deg/s.The simulation results were verified by testing the mixing power,and the mixing weight of asphalt mixture was determined to be 10kg～14kg(filling ratio62.5%～87.5%),and the motor speed range was 35r/min ～50r/min(210deg/s～300deg/s).The consistency has been found between the experimental results and the simulations.The improved mixer was used to mix the asphalt mixture under reasonable mixing parameters.The mixing temperature of rubber powder asphalt mixture with high viscosity and elasticity was confirmed as 177℃ and the compaction temperature as 155℃ in the way of equivalent mixing power.The construction temperature determined by mixing power of rubber powder and high viscosity and high elastic asphalt mixture is significantly lower than that determined by "viscosities and temperature" test curve of rubber powder and high viscosity and high elastic asphalt mixture,which is more consistent with the actual engineering situation.According to the above research results,the construction temperature of the asphalt mixture with high viscosity and high elasticity was verified in the actual engineering application and all indicators were proved to demonstrate the conformance to the specification.