Mixed-mode fracture toughness of high strength FRC: a realistic experimental approach

Abstract Unfortunately, fibrous composite materials' mixed-mode fracture toughness ( K eff ) was measured using inappropriate through-thickness cracked (TTC) specimens. The problem with such specimens is the ignorance of fibers in pre-notch surfaces, i.e., no fiber bridging behind crack tip. In present paper, a real fiber-reinforced concrete (FRC) experimentally determined matrix (MC) Traditional were also adopted for comparison. effect length (35 mm, 50 and hybrid fibers, 50% from each length) mode mixity M e ), = 0, 1/4, 1/2 studied. Hooked end steel volume fraction equal to 1% used. All beams crack-length-to-beam-depth ratio 0.3 tested under three-point bending I mixed-mode. span/depth two all Since there equation predict MC inapplicability Griffith's theory due difference paths, new realistic procedures suggested overcome this dilemma. results indicated that recorded lower initiation load than peak load. contrast, coincides case TTC This reflected role tip retarding reach their ultimate capacity after initiation. increased increasing . Although long higher energy, on FRC marginal minor loads. specimen approach estimating FRC.