Study On Adhesion Strength Of Bridge Deck Overlays Using Crumb Rubber Concrete

Crumb rubber concrete is a new type of concrete studied by many scholars in the world now, characterized by low elastic modulus, large deformation, high energy dissipation and extremely good crack resistance, which meet the need of bridge deck overlays. There are many deficiencies of traditional materials, such as asphalt concrete and Portland cement concrete, which make the overlays weak link of whole deck system. More important, the working performance and durability of the bridge is affected. So it develops a new application on engineering to use crumb rubber concrete in bridge deck overlays.In this paper, the shear bond strength between crumb rubber concrete and current concrete is obtained by experiment, which contains 0, 5%, 12.5% rubber. The results indicate that with the increase of rubber content, shear bond strength gradually increases, then reaches its peak,and decreases even less than current concrete with 12.5% rubber.After analyzing stress feature of bridge deck overlays, with a simplified computation mode of overlays, the mechanical equations are obtained under some necessary presumptions. In the aspect of mechanics ,conclusions are listed as follows: (1)There is close connection between the destruction of overlays and shear adhesion strength. (2)Fracture interval of overlays has nothing to do with materials, while fracture size is related with materials.Finally ANSYS is used to study structure stress and strain under different deck overlays materials, different intensities of contacts in the static and dynamic conditions. The results show that: (1)Structural deflection increases, while elastic modulus of deck overlays decreases. (2)The stress of the pavement layer is closely related with deck overlays materials, so the use of crumb rubber concrete decreases the layer shear. (3)The stress of steel in the deck overlays is related with materials, while using crumb rubber concrete increases the steel stress of the same nodes. (4)The mechanics of overlays and bridge deck is directly affected by shear bond property, which is highly required in engineering. (5)The contact stiffness fkn is taken 0.1 and 1, and the results difference is less than 6%. The smaller is selected to improve computational efficiency. Therefore, it can be judged preliminarily that the deck system is more rational when crumb rubber concrete deck is applied as bridge deck overlays material.