Research On The Properties Of Polypropylene Macro-Fiber Concrete

In the modern civil engineering, cement concrete has become the indispensable building material. Application of ordinary concrete is limited due to its inherent shortcomings. Polypropylene fiber is a new type of reinforced fiber, which has a lot of benefits. Therefore, research on the properties of polypropylene fiber concrete is benefit to promoting the application of polypropylene fiber concrete in engineering.In this paper, the performances of fresh concrete and mechanical properties, durability of hardened concrete were studied with different contents of polypropylene fine fiber, polypropylene macro-fiber and hybrid polypropylene fibers. And this research work provides the experimental basis for application use of polypropylene macro-fiber in concrete engineering.The results show that mixing polypropylene macro-fiber with concrete can reduce fresh concrete slump and increase the air content of fresh concrete. When the mixed content of polypropylene macro-fiber up to 6kg/m3, slump of fresh concrete decreased obviously. The compressive strengths of 7d and 28 d hardened concrete decreased with the increase of polypropylene macro-fiber content and compare to the compressive strength of reference concrete, but the compressive strength of 7d and 28 d hardened concrete did not decreased haipidly. The splitting strength and flexural strength nearly decreased comparing with the reference concrete. Shock resistance of hardened concrete increased significantly with the increase of polypropylene fiber content.When concrete mixed with hybrid polypropylene fibers, which have most influence on the impact prperties. And when hybrid fibers content is(1.6+6.0)kg/m3, the Shock resistance of which increased about 3.6 times compared to reference concrete. Shrinkage and carbonation depth of hardened concrete in various age were nearly same or slightly smaller to reference concrete.