Experimental Study On Pavement Concrete Reinforced By Layered Hybrid Fiber

Based on the analysis of superior and weak properties on plain concrete and only one fiber reinforced concrete, in view of the problems existing in the study of fiber reinforced concrete, a new type of fiber reinforced concrete is developed in this paper, which is called Layered Hybrid Fiber Reinforced Concrete (LHFRC). Allow for economy and properties, steel fiber, propylene fiber and polyacrylonitrile fiber are selected to jumble at small addition (by volume). Steel fiber is scattered on the top and the bottom of specimen, while propylene fiber or polyacrylonitrile fiber is equably scattered in concrete. First, through contrast experiment of six kinds of concrete, the effects of three types of fiber on concrete are discussed and the elementary mechanical properties(such as compressive strength, tensile strength, bending strength, modulus of bending, compressive stress-strain relationship) of LHFRC are obtained. Next, the optics microscope and scanning electric microscope tests demonstrate that propylene fiber and polyacrylonitrile fiber are scattered equably, the combination with concrete is perfect. At the same time, the anti-cracking function of propylene fiber or polyacrylonitrile fiber is found, which is good to the durability of concrete. The reinforcing and failing mechanism of LHFRC are investigated. Finally, load stress and temperature stress of hybrid pavement slab are calculated through Finite Element Method(FEM) with Winkler's soil model, Von Mises' strength theory and three-dimension block element for mesh-division. The testing result and analysis demonstrate that the properties of concrete(strength, anti-crack , toughness, durability etc.)are improved greatly by hybrid fiber, therefore, LHFRC can be widely applied to pavement, industrial ground, hydraulic engineering, buildings and other fields.