FRACTURE TOUGHNESS INVESTIGATION OF POLYVINYL ALCOHOL REINFORCED CEMENT COMPOSITES BY SINGLE-NOTCHED THIN SHEET

The hardening load-crack mouth opening displacement curves in uniaxial direct tension are obtained for the single-notched thin sheet made of polyvinyl alcohol reinforced cementitious composites. Besides, multiple radiate microcracks arises along the notch tip and some subparallel cracks appear along the whole specimen apart from the notch tip, while some brittle and quasi-brittle composites such as cement paste and concrete split along only one path. So the fracture mechanism of polyvinyl alcohol reinforced cementitious composites is very different from some strain softening composites whose fracture toughness can be evaluated by double-K fracture criterion and fracture energy. Therefore, two toughness evaluation norm of initial fracture toughness and dissipation energy are discussed for polyvinyl alcohol reinforced cementitious composites.