Evaluation On The Damage Condition And Analysis Of The Formation Causes Of Longitudinal Cracks On Bituminous Pavement In Seasonal Frozen Region

This thesis is made with the data on the basis of field investigation of high-class highway in the seasonal frozen region in Heilongjiang province, statistics is spread on the regularity of place distribution of longitudinal cracks on bituminous pavement, and the result shows: longitudinal cracks of high-class highway have the centrosymmetric distribution symmetrically with median separator as the center, and mainly rest in the left and right wheel track on the passing lane and carriageway of freeway. While the longitudinal cracks on the motor way distribute dissymmetrically. On the left, longitudinal cracks mainly appear on the right wheel track of carriageway, and on the right, they often spread near the central line of the way and the left and right wheel track. Evaluation model of destruction grade of longitudinal cracks is set up with the matter-element theory of extenics, in which the qualitative and quantitative evaluation is made for the index on length and width of cracks through the calculation of extension dependent degree. And the dependent degree is in token of damage degree of longitudinal cracks and the relation between various classes, thereby it can be realized to estimate the classes to which damage degree of longitudinal cracks belong. To specify the main formation causes of bituminous pavement for different routes in the seasonal frozen region, compositive analysis on the longitudinal cracks formation will spread on the basis of the form of longitudinal cracks and its regularity of place distribution, as well as transportation load and frost thawing, and the result shows that under temperature, water, height of subgrade and transportation load, the main causes rest in reflection of longitudinal cracks on base course, shortage of subgrade strength after frost thawing, differential frost heave of road, ununiformity of subgrade bearing capacity from water invasion and differential subsidence of new and old subgrades. The result can provide parameters for road design and technical approval for maintenance and management. And there will be practical significance in prolonging the life of highway and in improving the service in the seasonal frozen region.