Basic Theoretical Analysis And Research Of Fatigue Damage On Semi-Rigid Pavement

With the development of high grade road in our country these years,the highway system has been basically established. But, following some new problems, the early corruption of the roads has become more and more serious. The combination between semi-rigid base and asphalt surface course is the main form of high grade road in our country that has been used widely. The reflection crack in surface layer which caused by rupture of the base layer often occurs that proved huge economic losses. It becomes an important subject that the civil engineers have to resolve. The injury of road structures under the vehicular load,temperature and humidity effect of the surroundings belongs to fatigue damage. The main measures to deal with fatigue problem of road structure are experiential way based on experiments and mechanical way based on the strength theory. But the effects of these measures were unsatisfactory in actual application. The main reason is lack of researching on the injury mechanisms. So we have not enough reasonable method bases in practice.This paper has discussed the essential characteristic of irreversible damage through the energy viewpoint. It uses the methods of solid mechanics and thermodynamics of irreversible processes to analyze the reason of the defects of old analysis measures for fatigue problem and sum up the main generation mechanism of irreversible damage in different pavement-materials. The innovation point in this subject is to connect the conception of"entropy"which shows the irreversible processes in thermodynamics with the irreversible processes in structural damages and using thermodynamical quantities to represent the constitutive relation of irreversible damage with the entropy production. It has described the damage process of pavement in mathematical form and sums up the principal pathways for prolonging the life of road. Especially, the thesis tries to use the profound meaning of entropy in other disciplines to enrich and expand the conception of pavement design, shows some new opinions about functional pavement design which is based on allocation of irreversible damage.