Experimental Research On Durablity Of Modified Polypropylene Fiber Reinforce Concrete

For nearly two decades, infrastructure construction in our nation have been developed rapidly, most of which is concrete engineering. Through the investigation and study in recent decades, concrete materials show a series of durability of the effects of physical phenomena under the adverse environment and operating conditions, such as concrete carbonization, protective layer spalling, crack extension, reinforcing steel bar rusting, infiltrating and freeze thawing damage, aggragate chemical attacking, etc.That is why improving the durability while ensuring the concrete structure intensity have become a hot topic in academia. Currently, engineers mainly improve concrete durability through adding steel fiber, synthetic fiber, or both which they mutual act and complement with each other. Concrete mixing with modified polypropylene fiber (which is also called resemble wire-steel fiber) and common polypropylene fiber are designed to research. Based on a large number experiment and detailed theoretical study, the effects on concrete which is exert by the different fiber quantity groups are analyzed and compared. The main research work and achievement are as follows:1.7 quantity groups of modified polypropylene fibers are designed in the experiment. Concret performance experiment and mechanical experiment which include slumps test, fiber dispersity test and resist compression, bending test and fracture energy test is imposed to preliminary confirm the modified pp-fiber influence of the concrete performance and mechanical property.2. The other experiment focus on extensive research on durability of concrete. Carbonization, impervious performance, crack resistance, chloridion diffusion, frost resisting, rush strength and hyperthermia performance of different quantity modified pp-fiber is tested and analyzed. The effect of modified pp-fiber on durability of concrete is researched, and the optimum mix proportion which can improve durability of concrete is obtained accordingly.Experimental studies of modified polypropylene fiber reinforced concrete indicate that:modified polypropylene fiber doping could partly improve durability of reinforced concrete,expericially on the performance of frost resisting,chloride ion diffusion resisting,impermeability,crack resistance and high temperature resistance.For this reason, modified polypropylene fiber could be put into use and extended to road engineering and irrigation project.