Research On Mechanical Properties And Crack Self-healing Of PVA Fiber Reinforced Cementitious Composites

The brittle cracking of ordinary concrete materials have great impact on theperformance of engineering structures,sothe emergence of the modern highperformance concrete composite materials will play an important role to alleviatethe dilemma. To meet this demand, the paper developed the PVA fiber reinforcedconcrete composites (PVA-FRCC).It has high performances such asself-compacting, high ductility, small fracture width and self-healing crack. Themain work is as follows:(1) In order to achieve self-compacting properties, it’s be studied on theoptimum content of super plasticizer and viscosity agent of the fresh PVA-FRCC bytesting the flow properties and viscosity.(2) It’s been studied thatthe effects of different content of fly ash and differentfiber contenton the compressive strength of the PVA-FRCC. The comparativestudies of the concrete in varied ages have been carried through four-point bendingtest.The test results showed that: the compressive strength of concrete mixed withPVA fiber is higher than the concrete with PVA. By adding PVA fibers can increasethe strength of concrete. Different content of Fly ash have different compressivestrength. Specimen under the same condition, the longer the age, the bigger thestrength through the four-point bending test.(3)It’s research on PVA fiber reinforced cement-based composites self-healingproperties. Through the PVA-ECC tensile specimens, conservation under differentconditions, the use of high-power optical microscope to observe the crack surfacePVA-ECC self-healing, On this basis, explore the PVA-ECC mechanism andself-healing process, and after further analysis of self-healing properties ofPVA-ECC reason for the difference from healing.(4) Utilizing the finite element simulation of fiber pulled out from the matrix,come to a conclusion: fiber tensile strength is low, the bonding strength betweenfiber and matrix interface is high, crack penetrates the fiber matrix, fibre is brokenand the material is fractured; Fiber tensile strength is high, the bonding strengthbetween the fiber and matrix interface is low, the fiber is pulled out from the matrix before the fiber is broken.