Real fracture toughness of FRC and FGC: size and boundary effects

Abstract The present dilemma is how to simulate the real crack in full depth (FD) fiber-reinforced concrete (FRC), FD FRC, get actual fracture toughness of such fibrous composites, i.e., through-thickness pre-cracks are inappropriate for materials. To overcome this dilemma, a new technique was adopted create pre-matrix (MC) without cutting fibers bridging two surfaces pre-crack. main objective work study size and boundary effects on MC-FD FRC functionally graded (FGC). Forty-eight MC-FGC beams with three different span ratios L / d equal 4, 5, 6, beam depths same have been tested under three-point bending. All pre-MC length ratio ( o ) 1/3. Hooked end steel 1% fiber volume fraction produced FRC. FGC consist layers, layer at tension side, normal strength middle beam, high compression side. applied load versus all beams' mouth opening displacement (CMOD) curves analyzed. load/CMOD results showed that having constant recommended capture independent effect parameters. law (SEL) model (BEM) good candidates predict effect. According maximum non-damaged defect concept, SEL more reliable predicting MC than BEM.