Study On Crack Mechanism And Maintenance Technology Of Semi-rigid Pavement In Freeway

As many early freeways become overhauled, the repair task is becoming serious. As the major style of pavements in our country, semi-rigid pavement has turned up much early damage because of the over loading, Among the reasons of the overhauling, crack damage plays an important role, and the crack causes water damage in advance. So it is important to repair the crack. Depending on the overhauling of Jiqing Freeway, this paper summarises the experience in the crack maintenance, studies the styles and mechanism of crack damage in freeway, and optimizes the maintenance technics.This paper summarizes the distribution of crack damage in Jiqing Freeway, then it gains the changing rules of the crack damage according to annual checking data, meanwhile, based on the distributing and changing rules of the crack damage, it analyses the mechanism of crack's emerging and developing in theory.This paper studies the token measure of damage and maintenance measure, puts forward the suggested token measure, which can indicate the distributing and changing rules. The study puts forward scientific measure in damage analysis, maintenance measure evaluation and maintenance management.Using ANSYS, this paper does three-D finite element analysis in three conditions, which contain pavement with perfect structure, crack in grass roots and surface crack, it studies the stress in pavement under the conditions of temperature and standard traffic load, explains the mechanism of crack's emerging and developing, then it studies the inducing effect of the transverse crack to other damage, especially to the longitudinal crack, and finally gains the mechanism.The paper analyses crack repairing measure, puts forward that the notching should be confirmed by the crack shape and the shape should be designed with circle, ellipse.Optimized measure is done to the original design measure in Qingdao section, in allusion to the common crack at grass roots, the paper analyses the stress in three conditions, which include structures with up grass roots milled and not, structure with up grass roots left and fiberglass geogrid covered, in the end, the reasonable milling layer is come up with.The study has important significance in the maintenance and prevention of the damage in freeway.