Experimental Research On The Mechanical Properties Of PVA Fiber Reinforced Cementitious Composite

Concrete was invented more than 100 years ago,and has been widely applied in many engineering areas, because its many advantages, such as high compressive strength, a wide range of sources, the traditional construction craft simple and so on merits. on the other hand, its shortcomings such as brittleness and easy to crack limit its development. The modern engineering structures ask for higher and higher performance of concrete because of their developing trend to great span, light type, tall building, expansion to underground and sea as well as the direction for human being to intellectualized society. In order to overcome its own defects of cement-based material and increase its toughness, adding some textile fiber in the cement substrate may improve cement substrate performance, which is one of the regular methods. Based on those, lots of experimental researches have been done on PVA fiber reinforced cementitious composite such as uniaxial compression tests, direct tensile test, four-point bending test, bending and so on in this article and the following works have been completed:1, Detailing ingredient and fiber composition mechanism of PVA fiber reinforced cementitious composite substrate; trying to match many times for its composition material's mixture ratio, the material release sequence, the agitation craft and so on; satisfying the material the operating performance request; obtaining a variety of physical and mechanical properties.2, Doing the uniaxial compression experiment of cubic and prism specimens of PVA fiber reinforced cementitious composite; obtaining its compressed stress - strain curve; analyzing its compressed stress - strain curve characteristic and influences of the different substrate allocated proportion and the textile fiber parameter.3, Conducting the direct tensile experiments for straight plate-shaped and dumbbell-shaped specimen of PVA fiber reinforced cementitious composite; obtaining PVA fiber reinforced cementitious composite ultimate tensile strain that is about 1.8%; showing the feature of obvious strain hardening because of the appearance of many small fine cracks in both straight plate-shaped and dumbbell-shaped specimens; reinforcing the tensile zone with a thin aluminum plate on the end of specimen and avoiding the appearance of cracks in the tensile zone on the end of specimen or even tensile failure firstly; analyzing and simplifying tensile stress-strain curves according to the experimental results and obtaining tensile constitutive equation of PVA fiber reinforced cementitious composite.4, Testifying the excellent deformation capacity of PVA fiber reinforced cementitious composite materials through the plate four-point bending test; evaluating quatitatively flexural toughness of PVA fiber reinforced cementitious composite through ASTM-C 1018 toughness indexes and JCI-SF4 equivalent bending strength method; proving the much higher flexural strength of prism specimens with fiber than without fiber through the bending test.