EFFECT OF POLYOLEFIN FIBER ON THE ENGINEERED PROPERTIES OF CEMENT-BASED COMPOSITES CONTAINING SILICA FUME

摘要

This study is aimed to evaluate the engineered properties of cement-based composites which comprise polyolefin fibers and silica fume in the mixes. Material variables include water-cementitious ratio, dosage of silica fume, polyolefin fiber length and dosage. Compressive strength, splitting tensile strength, direct tensile strength, resistivity, rapid chloride penetration test and microscopic observation were conducted. Test results indicate that the specimens containing silica fume have higher compressive strength than fiber and control specimens. The specimens with polyolefin fiber and silica fume have much higher tensile strength and ductility than the control and silica fume specimens. The specimens containing silica fume and polyolefin fiber demonstrate better resistance in chloride penetration than polyolefin fiber composites or silica fume composites. For a given volume fraction, short polyolefin fiber performs better than long polyolefin fiber in improving concrete properties. The specimen containing silica fume significantly increases in resistivity and decreases in total charge passed. SEM microscopy illustrates that the polyolefin fiber acts as the crack arresters in concrete, which can inhibit internal crack propagation.