MECHANICAL PROPERTIES OF PVA FIBER REINFORCED CEMENT COMPOSITES FABRICATED BY EXTRUSION PROCESSING

Discontinuous polyvinyl alcohol (PVA) fiber reinforced cement matrix composites fabricated by an extrusion process were investigated. The extruded composites have exhibited a postpeak strain hardening type of response with an enhanced composite strength. Tensile strength of extruded composites was dependent on the fiber fraction used, while the flexural strength and deflection at the peak load were influenced by both the fiber fraction and the matrix composition. Larger fiber volume fraction, longer fiber length, and higher cement content lead to a higher flexural strength, a larger deflection at peak, and a higher elastic modulus. Fracture process was studied using laser Moire interferometry and scanning electron microscopy. It was observed that sequential multiple cracking was associated with the strain hardening type of response and that the spatial distribution of fibers can control the sequence of multiple cracking. Interface between fiber and matrix was also studied using continuous, aligned fibers and with the help of Moire interferometry.