Application Of Glass-fiber To Delay Reflective Crack In Asphalt Overlay

At present, the reflective cracking in the asphalt overlay paved on the existing cement concrete pavement is the common problem. The problems of reflective cracking in composite pavements are studied by home and overseas scholars. But reasonable and feasible technique measure is not formed. This paper is based on Hubei province's project of used roads'reformation in city of Huanggang, studied the delaying reflective cracking of glass-fiber on the asphalt overlay.This paper has analysed the take form mechanism reflective cracking's expansion way of compound roads, as well as the damage to the roads; ananalysed some prevention measures on the reflective cracking. The main prevention methods have:increase the asphalt concrete overlay thickness, lay a piece of stress absorption layer, between the old portland cement concrete pavement and asphalt concrete overlay, and so on. This paper also anasysed the good qualities and shortcomings two main kind of stress absorption layer, and according what I am studying is the loading stress here, finally choose the glass-fiber to be the stress absorption layer.The subject adopts the layered elastic system theory, builds two models of the compound road, and analyzes the analytic solution of stress and displacement according the borders conditions.Finally, I build three-dimensional finite element model of the compound road based on ANSYS, carry out comparative analysis by a few form data, and find out:with the increase of the asphalt's thickness, the composite pavement's stress will decline, but the asphalt can not too thick, as on the one hand it is too expensive, on the other hand the effect is not obvious when the asphalt is too thick; with the increase of the asphalt's modulus of elasticity, the composite pavement's stress will decline; with the increase of the glass-fiber's modulus of elasticity, the composite pavement's stress will decline; and the glass-fiber's modulus of elasticity also can not be too big, as when it is too big, the stress under the asphalt will increase. Usually, we choose the glass-fiber with the lower modulus of elasticity.