Study On Composite High Modulus Asphalt Pavement Of Tunnel

In the highway tunnels which have been built,the cement concrete pavement structure is the most widely used.However,in the closed tunnel environment,the noise caused by the cement pavement is large and the driving comfort is not high.Some researchers began to apply asphalt pavement to highway pavement,the cement concrete pavement and asphalt concrete pavement into a composite asphalt pavement structure.Asphalt pavement has a very good flexibility,can ease the road during the road generated by the impact of stress,reduce tire wear.In recent years,with the vehicle overload,the phenomenon of traffic channeling frequent,some asphalt pavement in less than a year's time there have been varying degrees of rutting,pits,cracking and other early diseases,the use of asphalt pavement performance Resulting in a certain impact,reducing the service life of asphalt pavement,but also increased the asphalt pavement maintenance costs.Therefore,it is necessary to propose a new type of tunnel compound asphalt pavement structure,to further improve the performance of composite asphalt pavement to meet the growing demand for traffic volume.In this study,the modulus of the asphalt mixture was increased by the addition of PR MODULE high modulus admixture.The influence of different dosage of high modulus admixture on the optimum aspect ratio of asphalt mixture was studied by Marshall test method.The influence of high modulus admixture on the road performance of asphalt mixture was analyzed by rutting test,low temperature bending test,soaking Marshall test,freeze-thaw splitting test and so on.A good reasonable dosage of high modulus admixture was proposed.By adding the grinding slag powder,polyvinyl alcohol fiber method,the ordinary cement concrete made of high bending toughness concrete,to improve the anti-bending strength of cement concrete.The high ductility,high toughness and micro-cracking characteristics of PVA fiber are fully utilized,and the maximum width of the crack is controlled within 100 ?m.Slag powder is a superfine active mineral material,mainly play the role of filling andvolcanic ash effect.In this study,a new type of tunnel composite asphalt pavement structure is proposed: high modulus asphalt concrete surface layer + interface waterproofing layer + high bending toughness concrete lower layer + leveling layer + tunnel surrounding rock foundation.By analyzing the three-dimensional finite element model of ANSYS,the stress distribution of the composite structure and the inter-layer interface under the load and temperature gradient of the composite asphalt pavement are analyzed,and the rationality of the composite high modulus asphalt pavement structure is verified,Which provides important parameters for the rational design of composite asphalt pavement.