Economic Aspect of Hybrid Fiber Reinforced Composite

The aim of this presentation is to recommend an economical technique for preparing fiber-reinforced mortar for blast resistant structures using polymer fibers. Fiber-reinforced concrete was developed to improve ductility by preventing micro-cracking. It is also used to strengthen blast resistant structures, and to prevent spalling under the fire conditions. Because of the better mechanical properties and bonding performance, metal fiber is mainly used for the blast resistant structure. However, because of the high cost of the fiber, the cost of the reinforced cementitious composite is higher than normal concrete. This is especially true for short steel fiber where its high cost has to be weighed against its outstanding performance. As a solution, a more economical substitute can be found in polymer fibers of nylon and polyvinyl alcohol fibers, which cut costs without a significant decrease in performance. In this study, for fiber-reinforced mortar, each fiber and combination of fibers incorporated made up 1% to the total volume of the mortar. For fresh state properties, although the mortar contained combined fibers, there was no significant decrease in flow and air content. As the polymer fibers were combined with steel fibers, approximately 35% of tensile strength and 12% of flexural strength decreased. However, from the strain-stress relationship, the fiber-reinforced mortar with combined fibers showed more favorable results than single steel fiber. The results of this study are expected to contribute on the economic approach of fiber-reinforced cementitious composites using combined fibers.