Asphalt Pavement Overlay Mechanical Analysis And Fatigue Life Prediction

The asphalt overlay is one of the mostly used measures in maintenance and rehabilitation of highway asphalt pavement, according to the character of asphalt overlay, finite element method is employed to analyze the mechanical condition of the overlay and the overlay's fatigue life is estimated with fracture mechanics.The mechanical condition of the overlay under vehicle load, temperature stress and the coupling of vehicle load and temperature stress is calculated , the factors effect the mechanical condition of the overlay are analyzed; the mechanical condition is calculated when geosynthetics is laid and the geosynthetics' inhibition to reflective crack is analyzed; based on fatigue fracture mechanics, the fatigue propagation life of asphalt overlay under vehicle load and temperature stress is estimated and contrasted with the practical engineering; on account of fatigue propagation life, this paper brings forward the structural design method of overlay. It is shown that the characters of pavement structure (such as modulus, thickness of overlay and width of crack etc.) and the properties of vehicle load (as axle load, distribution of load and horizontal load) have different effect on the mechanical condition of the overlay, and there are some regularities to find; there is great temperature stress in overlay caused by low temperature, while the stress in overlay decreases because the coupling of temperature stress and vehicle load; the use of geosynthetics has inhibition to the propagation of crack in the overlay; and it is feasible to estimate the fatigue life of the overlay accurately by the theory of fatigue fracture mechanics.