Experimental Research On The Behavior Of Polypropylene Fibre And Rubber Modified High Strength Concrete Under High Temperature

Being an important developing direction, because of its virtues, such as big modulus, little distortion , high strength concrete is being used in wider and wider range. But one of its obvious disadvantage is the trench to explode under high temperature, and that will lead to cast of concrete, the exposure of the steel bar and the descend of the endurable capacity of the construction or the most serious outcome that the building breaks down. There has been a lot of methods to improve this defect of high strength concrete, for example, adding steel fibres, polypropylene fibres, or mixing the two ones into the concrete. Being a high molecule material hard to decompose in normal environment, the dealing of the wasted rubber has been a global problem having something to do with environment protecting and resources using. The mixing of the processed rubber powder can obtain many merits , for example, improving the shake performance, the penetrating of water and gas, the performance of extend and toughness, lowing down the concrete' s mass, isolating the noise, penetrating the water and gas, and that has been applied in engineering widely.The mixing of polypropylene fibres and recyled rubber not only can improve the exploded performance of the high strength concrete under high temperature, but also can make use of much more rubber and low down the polypropylene fibres' s quantity. Through mixing , this paper study the improving value for the exploded performance of high strength concrete. The study is as follows:1 By comparing, this paper got the affection of the rubber, polypropylene fibre and the two ones to the new maken concrete' s slamp and expanded value. The outcome indicated that the work performance of the concrete mixed by polypropylene fibre and rubbe powder is better than that only mixed by polypropylene fibre;2 By comparing the exploding appearance of the samples, got the different improved effect of the exploding performance of the samples mixed by polypropylene fibres, rubber and the two ones. The outcome indicated that the value for improving exploding by mixing polypropylene fibre and rubber powder is the same as polypropylene fibre only, but the former had huge economical and environment protecting benefit;3 Got the variational value of the compressive strength of the samples through the experiment of the cubic compressive strength after high temperature, and compared the variational value of the compressive strength of the samples mixed by polypropylene fibres only, rubber fibers only and the two ones through comparing the residual compressive strength ratio. The outcome indicated that the variational value of the compressive strength didn' t have obvious difference between the high strength concrete mixed by polypropylene fibre and rubber powder or polypropylene only or rubber powder only;4. Compared the variation of the quality of the samples after high temperature and the improved degree to exploding samples mixed by polypropylene fibres only, rubber only or the two ones through comparing the loss ratio of the samples. The outcome indicated that the exploding improved effect for the high strength concrete mixed by the polypropylene fibre and rubber is better than that mixed only by rubber powder, and it achieve the same effect as the polypropylene.The mixing of the polypropylene fibre and the rubber powder proved the resistance of high strength concrete to high temperature, the improved effects are not obvious different between the low and high volume.