Research On Fatigue Life Prediction Of Damaged Pavement Concrete Based On Meso-scale

Cement concrete pavement is one of the most important part of roads in China. However, with the growth of road traffic mileage, early fatigue crack in concrete pavement has become more and more serious. The main reason is that concrete macro-fatigue will result in meso-damage and meso-damage accumulation also may cause fatigue crack for concrete pavement. Therefore, through researching on micro-mechanics damage of concrete and predicting accurately fatigue life, it has a very important significance to take protective measures in advance for prolonging service life of concrete pavement. Supported by Specialized Research Fund for the Central Universities, this article is to predict fatigue life of concrete through researching evolutional mechanism of fatigue damage. Firstly, according to theory of continuum damage mechanics, it’s presented damage parameter with the help of stress redistribution. Secondly, it’s also given the method how to determine damage parameter through considering fatigue cumulative damage under multi-level different stress loading. Finally, fatigue model of concrete based on mesoscopic damage is put forward. In addition to increasing life of concrete, it can improve design level for concrete pavement and push the development of concrete pavement in China. The main conclusions are drawn:(1)Through analyzing damage constitutive mode of concrete, it’s very convenient to calculate with Kachanov model and applied to research on micro-mechanics damage of fatigue model for concrete. Above all, it has been systematically introduced fatigue cumulative damage of concrete. Based on that, it’s appropriate to determine damage parameter of concrete pavement by applying Miner rule.(2)It has been researched on evolution mechanism of concrete damage and analyzed effective stress drop and stress redistribution of damaged concrete. Finally, it has been discussed relationship between effective stress redistribution and damage parameter and also established expression between real stress level of damaged concrete and damage parameter.(3)Considering effects of effective stress redistribution, it has deduced fatigue damage model of concrete based on fatigue damage theory of concrete through analyzing fatigue properties under multi-level stress loading. Based on traffic volume investigation, it’s calculated fatigue cumulative damage with Miner rule during service life to predict fatigue life of concrete through fatigue equation of concrete.(4)Through investigating traffic volume for T highway in K8+900, it has predicted fatigue life of damaged concrete pavement and compared fatigue life based on fatigue damage equation of concrete with fatigue life of fatigue test. Last but not least, it can predict accurately fatigue life for concrete by using this model.