Study On Performance Of PVA-Fiber-Reinforced Cement-based Composite Materials

Higher strength bas been a goal for hundred years since concrete was developed.As an important structural material, strength is the main performance index of concrete.High strength is always deemed to be the essential feature of quality concrete. Whileaiming at high strength, people found many concrete structures generated cracks andeven broke down because of inferior material. The destructions are not caused by theinadequate strength, but by bad durability. Therefore, durability of concrete has been asimportant as strength and other performance indexes. People bring forward the conceptof high performance concrete. Mixing method is the primary approach for getting highperformance cement-based composite materials and fibrous reinforcement is core.Superposition principle is significant for increasing performance of materials.Although fiber concrete has more advantages than ordinary concrete, it still comesin restricts in engineering practice. For example, workability is relatively worse. Andfiber will lump or even break off during mixing, setting and vibrating. Adhesiveperformance also needs to be improved. The application is greatly restricted due to thehigh price of fiber. The PVA fiber is a kind of chemical fiber of low price, high strengthand high elastic ratio. PVA fiber has theoretical better reinforcement effect in concretethan other chemical fibers. But the study of PVA fiber applied in cement-basedcomposite materials is not attached importance. Taking PVA fiber from certain domesticfactory as subject investigated, this paper studied adhesive performance of PVA fiberand concrete, anti-crack effect of PVA in concrete and effects of various length andquantity of PVA on cement-based composite materials, which was compared to PP(polypropylene) fiber popularized in and out of nation. When cement-based compositematerials were mixed into PVA fiber, crack resistance was effectively improved andtensile strength was obviously increased. Not only deformation and destruction feature,but also shock resistance, impermeability, anti-shrinkage and bending ductility wereimproved in some degree. Tests showed that improvement in concrete performance ofPVA fiber was better than that of PP fiber. But PVA fiber would decrease workability ofconcrete. This study indicated that PVA fiber is an ideal reinforcement and anti-crackmaterial for concrete.