Study On Mechanical Properties Of PVA Fiber Reinforced Cementitious Composite Containing Nano-particles

In recent years, great attention has been paid to PVA fiber reinforced cementitious composites due to its ductility and high toughness and the characteristics of strain hardening and multiple crarking. And a large amount of researches have been carried out at home and board. Nano material has shown great potential applications in many fields as a new material with the unique nano effect. As research continues and costs fall, nano materials have expanded into high performance concrete. However, in the present study, the research on the mechanical properties and fracture property of PVA fiber reinforced cementitious composites containing nano-particles are rare. Through a large number of experiments, this paper shows the effect of fundamental mechanical properties, the evaluation results of flexural toughness and fracture performance influenced by the PVA fiber volume fraction, the nano-particles content and the particle size of quartz sand. The main contents are as follows:(1)The preparation theory of PVA fiber reinforced cementitious composites containing nano-particles was analyzed, and twenty series of mix proportion were determined. The influencing rule of the PVA fiber volume fraction, the nano-particles content and the particle size of quartz sand on the workability of PVA fiber reinforced cementitious composites containing nano-particles was obtained though the test of slump spread.(2)With 28d as test age, by using cube compressive strength test, axial compressive strength, cube compressive strength test after bending test, the influencing rule of the PVA fiber volume fraction, the nano-particles content and the particle size of quartz sand on the compression properties of PVA fiber reinforced cementitious composites containing nano-particles was obtained.(3) With 28d as test age, by using bending test, the influencing rule of the PVA fiber volume fraction, the nano-particles content and the particle size of quartz sand on the bending capability of PVA fiber reinforced cementitious composites containing nano-particles was obtained.(4) With 28d as test age, the flexural toughness was studied by the tests of three dividing point loading with beam specimens which size is 100mm ×100mm× 400mm. The influencing rule of the PVA fiber volume fraction on the flexural toughness of PVA fiber reinforced cementitious composites containing nano-particles was obtained with analyzing the test results by the evaluation method for flexural toughness of steel fiber reinforced concrete.(5) With 28d as test age, the fracture performance was studies by three-point bending test with pre-sawed beam specimens which size is 100mm×100mm×400mm. The influencing rule of the PVA fiber volume fraction, the nano-particles content and the particle size of quartz sand on fracture porperty of PVA fiber reinforced cementitious composites containing nano-particles was obtained by analyzing the effective crack length, initial fracture toughness, unstable fracture toughness, fracture energy as the evaluation indexes.