Design And Performance Research Of Rubberized Asphalt Thin-layer Topping Mixture

As a new type of pavement maintenance technology,rubber asphalt thin layer grinds waste rubber tires into rubber powder,prepares rubber asphalt according to a certain process,and applies it to pavement maintenance.Good,to achieve sustainable development of road construction.In this paper,relying on the key research and development projects in Guangxi,the research on the surface of rubber asphalt thin layer is carried out,which is of great significance for its application in the maintenance of highways in high temperature and rainy areas.Summarize the relevant specifications and standards of rubber thin-layer covering,determine the performance index requirements of raw materials,and measure the test results;set the thickness of the thin-layer covering to 2.5cm,and the porosity of 4%;based on the empirical method,formulate 8 types of 10-type gradation,There are 4 types of 8-type grading,and the Marshall volume index and the best oil-to-stone ratio of each grade are determined,and the VV and VMA prediction models are established.To study the effects of gradation,fiber and SBS content in asphalt on the high temperature,low temperature and water stability of asphalt mixture,0.25%wood fiber was added to the 10E gradation mixture,and on this basis,the SBS content was added as 0.5%,1.5%and 2.5%rubber asphalt were used to determine the corresponding properties of the mixture.In addition,the effects of thickness and freeze-thaw times on high temperature and water stability were also studied.The research shows that:adding wood fiber and increasing the content of SBS can significantly improve the performance of the mixture;reducing the thickness of the specimen,the rut depth of the mixture will decrease to a certain extent;grading has a significant effect on the performance of the mixture,with the Dc value and CA With the increase of the value,the DS value of the dynamic stability increases,the D value increases,and the maximum flexuraltensile strain value decreases;and the prediction model of the high temperature and low temperature performance of the mixture is established from the perspective of gradation.The manual sand laying method and the pendulum value method were used to measure the anti-skid performance of the mixtures at all levels,and based on the self-developed accelerated wear equipment of the research group,the decay law of the anti-skid performance of the asphalt mixture was explored.The research shows that with the decrease of Dc value,the pendulum value and structural depth increase continuously;the anti-slip decay rate of the 8-type gradation mixture is less than that of the 10-type gradation;increasing the load force will accelerate the anti-slip performance of the asphalt mixture.Attenuation rate;and from the perspective of gradation,the prediction model of anti-slip attenuation of the mixture is established.Carry out the anti-loose performance test of the mixture,and carry out the orthogonal test to improve the discrimination of the anti-loose ability of the mixtures at all levels.The research shows that the anti-looseness of the mixture is mainly affected by the gradation and the bituminous membrane;the anti-looseness of the mixtures at different levels can be clearly distinguished under the conditions of a water bath of 20℃,10 steel balls,and a rotation of 700 revolutions.Based on the Overlay Test equipment,the anti-reflection crack performance of the mixtures at all levels is studied.The research shows that:with the increase of the D value,the critical fracture energy value continues to increase;the cracking index is linearly negatively correlated with the critical fracture energy and load loss,and the load The loss and the critical fracture energy have a linear positive correlation.Based on Pavecool software to explore the influence of different factors on the effective compaction time of pavement compaction,the research shows that the paving thickness has the most obvious effect on the effective compaction time,followed by the effect of air temperature,followed by the wind speed,and the initial temperature has the smallest effect.