Fatigue Damage And Life Prediction Of Concrete

Cement concrete pavement is one of the most important structural styles of high-way. However, with the increasing mileage of construction year by year, the concrete pavement damaged prematurely becomes more and more obvious, which is mainly caused by the repeated loads act on it ,and finally fatigue failure occurs. Therefore, it is very fundamental to research the fatigue properties of concrete, identify whether the pavement damage accurately, determine the location and extent of damage, and then predict the fatigue life of concrete pavement. The research method combined the Finite Element analysis with theory is adopted in this article. Based on the previous experiment results, research the damage characteristic of concrete with the damage mechanics theory, define the appropriate damage variable and calculate the fatigue life from cumulative damage law.In the essence, the fatigue failure of concrete is the process of fatigue cracks initiate, propagate, and fracture finally. It is also the process of energy dissipation. So two new fatigue life predicted models are proposed, which is separately based on the plastic energy on the critical plane, and the total strain energy on the critical plane. Verifications of the models are achieved by comparing the predictions obtained by using the new models and experimental dates of concrete specimen under different loading conditions.Then, predict the fatigue life of concrete pavement under different load locations with the model of total strain energy based on critical plane. In addition, in view of the fact that more and more serious overload phenomenon nowadays, this article analyses the case from standard load and overload. Some repairing measures can be adopted for the pavement on time, according to the calculations and the three stages of concrete fatigue damage development. So as to bring some practical engineering significance.Finally, research the relations of fatigue crack growth rule and the crack tip plastic strain energy with Macroscopic Fracture Mechanics. So a fatigue crack growth model based on crack tip plastic strain energy is proposed. And predict the fracture crack growth life of a concrete plate with center crack.