Analysis On The Influence Of Interlayer Bonding Conditions On Pavement Cracking Of Main Road In Beijing And Its Improvement

Investigation of asphalt pavement condition revealed that cracking accounts for more than 70% of distresses.The drilled asphalt pavement cores showed that the top layer and the middle layer of asphalt pavement was separated and the interlayer bonding was almost completely lost,which accelerated fatigue cracking.Therefore,a good state of interlayer bonding between layers is the key for asphalt pavements to keep good road performance and prolong the service life.Firstly,the upper and lower layers were selected in order to study the interlayer performance.Comparative evaluation of 3 kinds of upper layer asphalt mixtures and 3 middle layer asphalt mixtures commonly used in Beijing were tested and evaluated on road performance after mixture accelerated aging.The upper and lower layers were recomanded based on balanced peformance.Secendly,pavement analysis models with interlayer contact conditions were developed,the influence of different interlayer bonding states,pavement temperature,horizontal load and thickness of surface layer on interlayer shear force were analyzed by using ABAQUS.Through orthogonal simulation,the technical requirements for interlayer shear strength was proposed.Thirdly,shear test and drawing test were used to evaluate and rank the performance of 5 kinds of interlayer bonding materials.Test results demostrated the influence degree of temperature,freeze-thaw cycle and aging on interlayer bonding properties.Finally,a new type of composite beam fatigue test which can evaluate the effect of interlayer bonding materials on the fatigue life of asphalt pavement was developed to improve the evaluation method of interlayer bonding properties.The results showed the interlayer bonding effect had a good correlation with fatigue life,the fatigue resistance property of the composite beam which used the rubber and SBS composite modified asphalt as interlayer material was the best.