Numerical Analysis Of Reinforcing Effect Of Rigid Anti-Crack Stickers Joint In Asphalt Pavement Covering Old Cement Concrete Pavement

Adding an asphalt overlay to the old cement concrete pavement can not only utilize the residual strength of the original cement concrete pavement,but also improve the service performance and driving comfort of the pavement.However,the joint of the original cement concrete pavement is the weakest position of the overlay structure,and the reflective cracks and local weak supports at the bottom of the slab are easily generated in this position.Aiming at this problem,this thesis proposes a high-strength anti-crack sticker—rigid anti-crack sticker,which is set at the joint and composed of steel plates.The three-dimensional finite element numerical analysis method is used to analyze the mechanical response of the pavement structure under the vehicle load and the effect of the rigid anti-crack stickers.The main research work includes:(1)Summarize the generation and expansion mechanism of reflective cracks in the asphalt pavement covering old cement concrete pavement structure according to the existing literature,establish a finite element model of the cement concrete overlaid asphalt surface structure,and conduct a preliminary analysis of the strength of the joints.Under the action of vehicle load,there is a problem of stress concentration at the bottom of the asphalt layer at the joint.Aiming at this problem,a reinforcement scheme of setting rigid anti-crack stickers at the joints is proposed,and the key analysis parameters of the pavement structure are summarized in combination with the mechanical analysis theory of the overlay pavement structure.(2)The analysis of the key parameters of the rigid anti-crack stickers to improve the asphalt pavement covering old cement concrete pavement structure shows that the rigid anti-crack stickers can improve the pavement by reducing the vertical displacement of the pavement structure and the deflection difference on both sides of the joint under vehicle load.The overall stiffness of the structure improves the load transfer capacity at the joints,reduces the stress extreme value at the bottom of the asphalt layer and improves the stress distribution of the pavement structural layer.The influence of rigid anti-crack stickers and overlay parameters changes on the overlay pavement structure with rigid anti-crack stickers is further analyzed,and different influencing factors(width dimension of rigid anti-crack stickers,modulus and thickness of asphalt overlays)are obtained.Mechanical response law of pavement structure under overlay.(3)Aiming at the problem that the overlaid structural layer is prone to disease under the weak support of the slab bottom at the joint,a finite element model of the overlaid structure based on the Winkler foundation is established,and the overlaid structure before and after the rigid anti-crack stickers is established on the slab bottom.Mechanical responses under different weak support conditions.The results show that the rigid anti-crack stickers have a good inhibitory effect on the deflection of the overlay structure caused by the deterioration of the bottom support,and alleviate the shear damage caused by the weak support at the bottom of the slab.