Research On Index Of Asphalt Mixture Water Stability Testing Based On The Strength Theory

Moisture damage has become one of the important form of the early damage of high-graded highway asphalt pavement in our country. Invasion of moisture into the pavement structure and promotes one or more of the visible forms of distress mentioned such as stripping, raveling, fatigue damage and finally reduces strength of pavement. The current test methods of evaluation index(Marshall stability divide splitting strength ) is mainly mixture indirect tensile ability And the method can not be very good at distinguishing the ability of resistance to water damage between different chemical composition of materials , sometimes the assessment results does not conform to practical application of pavement .In addition, studies show that aging factor has big influence in the performance of asphalt, but the study of aging factor moisture damage is relatively rare. In view of the above reasons, this paper based on water stability factor, considered the impact of aging factor, put forward a new kind of evaluation index to mixture water stability.Firstly, base on the coulomb Moore--strength theories of asphalt mixture, this paper chooses the uniaxial pressure test method to measure indexes of cohesion, friction Angle and shear strength. By analyzing evolution and susceptibility of those indexes under different environment factors choose of value as index, and reference standard test index proposed residual cohesion index, then analysis the variability of cohesion index.In research of environmental factor simulation, this paper analyses the action ways of moisture in pavement, choose 120h, 85 degrees oven aging as the way to simulate aging factor, with the analysis rate of different combination of moisture and aging factor simulation to cohesion index, eventually determine choice 60 degrees soaking 48 hours as cohesive index of environmental effect simulation method. Secondly, under 120h, 85 degrees oven aging and 60 degrees soaking combining different environment conditions, measure and calculate the residual cohesion index of the three different SiO2 content aggregate mixture at 60 degrees and 48 hours soaking, analysis the influence of residual cohesion in the different combination of environmental effect and material chemical composition.Finally ,comparing the penetration test residue cohesion index,the specification Marshall immersion remnants stability and the freeze-thaw splitting trials TSR results, has proved the effective and sensitivity of residual cohesion index.