Research On Mechanism Of Horizontal Cracks In Bilayer Continuous Reinforced Concrete Pavement

Continuous reinforced concrete pavement(CRCP)'s economy and durability are reasonably guaranteed when applied to roads with heavy traffic and heavy loads.At present,due to insufficient understanding of the new forms of damage and the mechanism of CRCP disease,horizontal crack is often attributed to punchout,which leads to deviations in the design and research stage.This thesis analyzes the generation and development of cracks from the three crack development stages of CRCP,including early transverse cracking,transverse cracking during service,and horizontal cracking.The early concrete transverse cracking calculation model was established through the measurement of the bilayer CRCP early historical temperature,to provide calculation basis and construction suggestions for preventing and reducing the early transverse cracks.The dynamic response of CRCP under vehicle load is measured;the elastoplastic constitutive of concrete is selected;the dynamic response model is calibrated,and the influence of various factors on the transverse cracking of CRCP is simulated and analyzed.The development of different initial transverse cracks is simulated.When the range of cooling or the vehicle load increases,the transverse crack extends to the depth of the road panel will be exacerbated,and the longitudinal steel will share a large amount of tensile stress when the crack propagates to the longitudinal steel,and the concrete near the steel layer also has tensile stress concentration at the same time.A calculation model based on the failure mechanism of horizontal cracks is proposed.The sensitivity analysis results show that the reinforced concrete bond-slip constitutive is the main source of tensile stress causing horizontal cracking of CRCP;controlling the width of the transverse crack can greatly reduce the risk of horizontal cracks;high elastic modulus,low linear expansion coefficient of concrete material,double layer of steel reinforcement and properly moving down the position of the lower reinforcement,good adhesion between the surface and the base layer,not wide or too narrow transverse crack spacing are beneficial to reduce the occurrence of horizontal cracks.The subsequent development process of the horizontal crack after the initial crack in the concrete near the CRCP steel layer under temperature and vehicle load is simulated.