Study On Asphalt Mixture Design And Pavement Performance For Ultra-thin Overlay

The ultra-thin overlay is a kind of preventive maintenance technology.Its method has good effect and fast construction speed,which is beneficial to prolong the service life of the pavement and can reduce the repair rate of the pavement.However,China has not yet introduced corresponding specifications for this technology to guide production practices.Based on this,this paper carried out indoor experimental study on ultra-thin overlay asphalt mixture,and discussed its engineering application,aiming to further solve the problem of pavement maintenance and repair.The main work of this study is as follows:(1)The principle of selecting raw materials for ultra-thin overlay asphalt mixture is proposed,including aggregate,filler,asphalt binder and adhesive layer emulsified asphalt.After selecting the raw materials,the corresponding indicators were tested,and the results showed that the raw materials used in this study all met the requirements of the specification.(2)Considering that the current specification is 4.75 mm mesh hole and 9.5mm mesh hole far distance,in order to better control the gradation curve of ultra-thin overcoat asphalt mixture,7mm control mesh hole is added;The maximum nominal particle size of the ultrathin overcoat asphalt mixture is determined to be 1.18 mm for the thickness of the aggregate.The ultra-thin overlay asphalt mixture with different void ratios is designed by CAVF method.The skeletal characteristics of the mixture were ensured;after determining the optimum amount of asphalt,the test and analysis of the three mixtures under the optimal asphalt dosage showed that the method can be used as the grading design method for the ultra-thin overcoat.(3)The pavement performance analysis of the three kinds of mixed materials under the optimal asphalt dosage was carried out,including high temperature stability,low temperature crack resistance,water stability,anti-sliding performance and interlayer adhesion performance.Three different temperatures were selected for the low temperature crack resistance trabecular bending test.The bending strength,bending strain and stiffness modulus of the three mixtures were studied.The water immersion Marshall test and the freeze-thaw split test were selected to evaluate the water stability of the mixture.The initial anti-slip properties of the mixture and the attenuation of the anti-sliding properties and the effect of temperature on the attenuation of the sliding properties were investigated.The interlaminar shear resistance of the mixture was studied by the oblique shear test.The optimum adhesion layer of the three ultra-thin overlay was determined,and the influence of temperature on the interlaminar shear strength was analyzed.(4)The construction requirements and quality inspection of ultra-thin overlay asphalt mixture were carried out,including the evaluation and treatment of old roads,construction process discussion,quality control and post-work inspection.