Mechanical Properties Research And Finite Element Analysis For PVA Fiber Reinforced Concrete

Fiber reinforced concrete can effectively limit the cement matrix microcracks expansion and extension, and improve the strength of concrete, to make up for the low tensile strength, small elongation, brittleness and other defects of ordinary concrete. This made a lot of scholars put fiber reinforced concrete as a key study, they did much mechanical properties test and numerical simulation about fiber reinforced concrete. The current mainstream numerical simulation method calculates by selecting one model that can best describe the constitutive properties of fiber reinforced concrete, considering it as a composite material.This paper selects polyvinyl alcohol(PVA) fiber reinforced concrete to conduct under axial compressive and flexural tensile tests. While using parametric design alone to establish PVA fiber unit, then importing ANSYS numerical simulation to make the Numerical Simulation and compare with the experimental results. In this paper, the main research work and conclusions are as follows:(1) This paper uses the Grasshopper of Rhinoceros to establish PVA fiber line units these are scattered evenly and distributed over time, and giving element type, material properties to the fibers, then converting into ANSYS recognized file. Connecting fiber unit nodes and concrete elements by Adjacent Regions to generate the restraint equation, setting constitutive relation of concrete and PVA fiber unit respectively. PVA fiber concrete model is established.(2) The author launched the axial compressive test of 100 mm × 100 mm × 100 mm PVA fiber reinforced concrete. The results show comparing with plain concrete, the compressive strength of fiber reinforced concrete of PVA volume content of 0.08%, 0.1% enhance about 3.9%, 1.2% respectively, the fiber concrete’s compressive strength of 0.2% volume fraction of PVA is slightly lower than the plain concrete. While using ANSYS to simulate the experimental, getting the stress- strain curve, it’s conducted that the tendency of the stress-strain curve is broadly consistent with the experimental results, only the peak stress and strain are greater than the test value.(3) The author launched the flexural tensile test of 400 mm × 100 mm × 100 mm PVA fiber reinforced concrete. The results show comparing with plain concrete, the flexural- tensile strength of fiber reinforced concrete of PVA volume content of 0.08%, 0.1%, and 0.2% enhance about 5%, 7 %, and 3% respectively. While using ANSYS to simulate the experimental, getting the load – deflection curve, it’s conducted that the tendency of the load-deflection curve is broadly consistent with the experimental results, only the peak load and deflection are greater than the test value.(4) By observing ANSYS cracks cloud, results show the crack extension of axial compressive test’ block is from the bottom to the upwards, then from the periphery to the middle until the entire block is crushed; the crack extension of flexural- tensile test’ block is from the middle section to the upwards, then expand from the middle to the ends until breaking, but it will not crack through the entire block. Observing from the distortion cloud, in the axial compressive test, the deformation of upper part is significantly greater than the lower part. While in the same horizontal plane, the deformation of the end parts is greater than the intermediate part; In the flexural- tensile test, the deformation of the ends and the middle part is more obvious. While in the same vertical plane, the deformation of upper and lower ends are basically identical.(5) The maximum tensile stress of PVA fiber is 151.42 MPa exporting in the axial compressive tests with ANSYS, less than its maximum tensile strength of 1704 MPa. In the flexural- tensile test, the maximum tensile stress of PVA fiber is 44.24 MPa, it’s also less than its maximum tensile strength. Results show the PVA fiber doesn’t break both in the axial compression test and in the flexural-tensile test. It is the insufficient adhesion(constraint equation) between fibers and concrete which leads to the fiber’s detachment work.