EVALUATION AND COMPARISON OF THE PHYSICAL PROPERTIES OF FIBRILLATED POLYPROPYLENE FIBER-REINFORCED CONCRETES

A comparative evaluation of physical properties for plain concrete and concrete reinforced with collated fibrillated polypropylene fibers is presented. Three concentrations of fibers, 0.1, 0.2, and 0.3 percent by volume, were evaluated. Evaluation included concretes with the fiber dosages indicated and a plain or control mix in two series: (a) fresh concrete properties, namely slump, unit weight, vebe time, air content, and concrete temperature; and (b) hardened concrete properties, such as compressive strength, static modulus, modulus of rupture, and pulse velocity at 7 and 28 days--the second being the replicate. Toughness indexes based on ASTM C1018, as well as the flexural toughness factors, were calculated. In addition, an equivalent flexural strength based on the Japanese standard was obtained. Inspection of plastic mixes and failed test specimens showed that there was no balling of fibers during mixing and fabrication of test specimens. There was a slight increase in the flexural strength as the fiber content increased. Addition of fibers produced less than 5% difference in the static modulus, compressive strength, and pulse velocity. On the basis of I sub 5, I sub 10 and I sub 20 toughness index data, the fiber concretes exhibited elasto-plastic behavior.