Research On Key Control Technology Of Warm Stone Mastic Asphalt Stone Pavement

Due to the high viscosity of rubber asphalt and the high construction temperature requirements of SMA mixture,the construction temperature of rubber asphalt SMA is as high as 180?~210?,which is 20?~40? higher than the general hot mix asphalt mixture.This creates certain difficulties for the construction of rubber asphalt SMA pavement and increases environmental pollution.By introducing warm mixing technology into the rubber asphalt SMA mixture,the construction workability of the rubber asphalt SMA mixture at lower temperature is improved,thereby reducing the mixing and construction temperature,and effectively solving the rubber asphalt pavement production and construction.The problems faced are in line with the green development concept proposed by the National 13 th Five-Year Plan.Firstly,through the laboratory test,the effects of different types and different amounts of warming agent on the penetration,ductility,softening point and aging performance of rubber asphalt were analyzed.The DSR test was used to study the temperature of the mixture and its rubber content.According to the influence of asphalt rutting factor,the viscosity-temperature regression equation of different warm-mixed rubber asphalt was obtained by Brinell rotational viscosity test,and a reasonable mixing and construction temperature range was determined by the equation.The test results show that: the amount of Sasobit warming agent should not exceed 4%,the mixing amount of DWMA-1 and Longfu EWMA warming agent should not exceed 6‰;Sasobit,DWMA-1 and Longfu EWMA three mixed rubber asphalt mixtures The mixing and compaction temperature drops are about 25?,20?and 22?,respectively.Secondly,using the Bailey method to design the gradation of three different coarse and fine aggregate ratios,the Marshall parameters are obtained through laboratory tests,and the best grades of the three grades are determined by the most compact state design method,and the ratio of oil to stone and tradition The SMA mix ratio design method yields an optimum ratio of oil to stone of only 1%.With 3% as the target void ratio,Marshall compaction test was carried out on three kinds of warm rubber asphalt SMA at different compaction temperatures.The test results showed that Sasobit,DWMA-1 and Longfu EWMA were mixed with SMA.The 154?,161? and 158?,almost the same compaction temperature as obtained in Chapter 2.The effect of warming agent on the road performance of rubber asphalt SMA was analyzed by laboratory test.The results show that Sasobit can significantly improve the high temperature performance of the mixture.DWMA-1 and Longfu EWMA have little effect on high temperature performance,but three kinds of warming agent It will reduce the water stability and low temperature crack resistance of the mixture to varying degrees.Considering the road performance of the mixture,EWMA warm rubber asphalt SMA has the best performance.The low temperature fracture damage parameters of the mixture were obtained through laboratory tests.The meso-crack propagation characteristics and fatigue properties of the rubber asphalt SMA mixture were simulated based on the NSCB meso-fracture model.The results show that the analysis of stress,displacement and crack propagation characteristics shows that the stress state and deformation trend of the NSCB mesoscopic model are consistent with the actual loading process.The crack propagation characteristic leaching is close to the actual cracking condition of the green mixture,indicating the NSCB mesoscopic model.is correct.The fatigue characteristics of each mixed rubber asphalt SMA under different stress ratios were calculated and analyzed,and the corresponding fatigue regression equation was obtained.Finally,the temperature field model of 3D pavement construction was established by using ABAQUS finite element software.The temporal and spatial distribution of temperature field of warm mix rubber asphalt SMA pavement was analyzed,and the influence of various factors on pavement temperature field and effective compaction time was analyzed.The main factors affecting the effective compaction time of the warm-mixed rubber asphalt SMA pavement were the paving layer thickness,wind speed and initial paving temperature through orthogonal experimental design and grey correlation analysis.The warm mixed rubber asphalt pavement was obtained by multiple linear regression analysis.The relationship between effective compaction time and various influencing factors provides guidance for pavement construction;analyzes the pavement construction temperature field under adverse environmental conditions,indicating that the warm mixed rubber asphalt pavement is hot mixed rubber under construction under low temperature or high wind conditions.Asphalt pavement can extend its construction time,but the ambient temperature must not be lower than 5?,and the wind level cannot exceed 4 levels.