Study On The Mechanical Properties Of Pva-high Toughness Cementitious Composites

Since the concrete's birth, people improve its strength by continuous efforts, but they often ignore its toughness, tensile strength of concrete is better than compressive strength is the problem that has not been satisfactorily answered. PVA fiber reinforced cementitious composites is a kind of mixture of concrete, mineral admixture, water, fine aggregate particle whose size is less than 5mm and PVA fiber composite material is made of cement-based material. The notable features of the material are:In the direct tension case, the ultimate tensile strain corresponding to the ultimate load is higher than 3%, resulting pseudo strain hardening and multiple cracking phenomenon. And the cracking in many cracks, the cracks' average width is about the 80μm with stability. The paper describes the PVA fiber reinforced cement based composites' research progress in domestic and abroad and its application. These developments indicate that PVA fiber reinforced cement based composite materials will occupy a more important position in the future engineering field. This article is mainly from the following aspects of the material's basic properties to start the study:1. Determine the order of the various components of the projection to ensure that fibers do not become bundles in the matrix group and evenly distributed. In addition, the mixture's fluidity is determined, and the excellent work of the material is shown.2. In the compressive strength test, with the different ratio 70.7mmX70.7mmX70.7mm cube block average compressive strength is between the 21.66MPa to 63.77MPa and mean compressive strength decreases with the content of the fly ash in the matrix increases.3. To study the material's flexural strength under three-point bending by using bending test, flexural strength mean value is between 16.95MPa in 12.46MPa, and with in the same applies with compressive strength, flexural strength decreases as fly ash content is monotonically increasing.4. Measured by four-point bending test material load-deflection curve, the proportion of the ultimate flexural strength, flexural strength, flexural elasticity modulus and flexural toughness index is studied. In the experiment's mix proportions, the sheet specimens' maximum deflection can reach 27mm.5. By direct tensile test to study the tensile properties, ultimate tensile strain of the specimen can up to 2.09%.