Control Of Early Cracking Of Cement Concrete Bridge Deck Pavement Study On Improvement Of Interalayer Bonding Property

The debonding and early cracking of cement concrete bridge deck pavement are very common and have affected the normal use of highway bridge.Existing research and practice mainly attribute the cause of fracture to shrinkage fracture,and pay less attention to the shrinkage fracture of very early age and the interlayer debonding caused by it.In this paper,theoretical analysis,experimental research and practical application methods are used to study the early cracking control of cement concrete bridge deck pavement layer and the measures to improve the interlayer bonding performance.The main work and achievements are as follows:(1)The causes of cracks in cement concrete bridge deck pavement are investigated.It is found that the shrinkage and interlayer debonding at the very early age are the main causes of cracks in cement concrete bridge deck pavement.(2)The origin and composition of early shrinkage of concrete bridge deck pavement layer are studied,and the control method of plastic shrinkage crack based on pore water saturation,the prediction method of concrete shrinkage based on hydration reaction degree and the determination method of early temperature gradient of concrete bridge deck pavement layer are proposed.Based on the engineering examples,the causes of cracks are analyzed for reference in decision-making.(3)The effect of different grooving parameters on the interlayer bond performance was studied by using the method of cutting the interface roughness and the method of splitting along the joint surface.It was confirmed that the interface roughness was the main factor affecting the interlayer bond,and the interlayer bond strength was much lower than that of intact concrete.The prediction model of bond splitting tensile strength under the main grooving parameters was established for reference in the evaluation of engineering grooving treatment effect.