Fiber Reinforced Concrete: Residual Flexure Strength Enhancement Using Surface Modified Fibers

Fiber reinforced concrete often fails due to poor adhesion between polymer fibers and the cement matrix which is caused by fiber flat and chemically inert surfaces. Such a phenomenon can be overcome by modifying the fibers with plasma treatment which activate and roughen their surfaces. Polypropylene-polyethylene and polypropylene macro-fibers were exposed to low-pressure cold dioxygen plasma treatment for 30 seconds. In order to quantify how plasma treated fibers can affect mechanical response of fiber reinforced concrete, notched specimens containing 0.75 vol. % of reinforcement were made and subjected to three-point bending test. It was shown that specimens with modified fibers exhibited up to 40 % improvement in residual flexural tensile strength than those containing reference reinforcement.