Research On Durability Evaluation Method Of Cement Concrete Pavement

The early disease of cement concrete pavement is serious at present, the disease caused by the road of insufficient durability has seriously restricted the development of the cement pavement. But the existing evaluation system of durability of concrete pavement is not perfect, can not meet the needs of the development of cement pavement. Therefore a perfect evaluation system for pavement is urgent need, to provide a reference for pavement design, maintenance and rehabilitation. To improve the road evaluation system, this paper based on several typical diseases caused by insufficient durability roads, such as cracks, broken plates, disengaging, dislocation, analyzed the generation mechanism of pavement disease and influencing factors; from the perspective of road material and structure composition, proposed evaluation index of concrete durability, and established the durability evaluation system of the concrete pavement.In this paper, fracture toughness, flexural-tensile strength and the index of the anti-scour ability of the base course are proposed as the evaluation index of the load-resistant performance. Through quadratic regression testing design and laboratory experiment, concludes the suggested value the index of the load-resistant performance and the optimum mixture ratio of cement concrete to meet the durability requirements. In the perspective of weathering resistance, obtained a result that air content is the main factor of the control of the performance of material frost-resistance and the deicer -scaling resistance, selected air control as the control parameter of the durability of concrete. As the same time, the range of pavement materials air content was given to meet the weathering resistance.In the perspective of Structural durability, Radius of the cavity was proposed as the index of the cavity beneath slab, and the prediction model of the erosion and cavity beneath slab was simplified, and the pavement condition classification was divided according the radius of cavity beneath slab; the amount of the faulting was selected as the index of faulting, the amount of the faulting was predicted and the relation was established among the amount of the faulting, the number of standard axle loads and the anti-scour coefficient; aspect of joint load-transfer, dowel bars'looseness is the immediate cause of the attenuation of load transfer, and the calculation formula of load transfer ability was proposed which considers the amount of looseness, and it can reduce the attenuation of joint load-transfer capacity by control the dowel bar diameter and the foundation modulus; according to condition that the influence of temperature warping was serious, analyzed the influences of thickness, temperature gradient, the base modulus to the workability of the panel and proposed using the thickness of the panel and base modulus to control the temperature warping and improve the durability of the concrete pavement.Synthesizes the above analysis, in this paper, Making a systematic suggestion for the concrete durability evaluation system and the process of comprehensive evaluation. At last, from the perspective of the material composition, mixture ratio and structure design, several advices and measures were proposed to improve the durability of cement concrete pavement.