MIXED MODE FRACTURE OF THE GEOPOLYMER COMPOSITES REINFORCED WITH RECYCLED STEEL FIBERS

Abstract

For the fiber-reinforced composites, strength-based criteria alone may fail to evaluate the bending response due to the long tail of the load-displacement curve. Hence, the fracture characterization of fibered composites has gained great attention worldwide. In this study, the mixed-mode fracture performance of the recycled steel fiber-reinforced geopolymer concrete was examined experimentally. The main test parameters were the amount of steel fibers (0 and 2% by mass) and the offset ratios of the edge notch (β = 0, 0.2, and 0.4). Several notched prisms were produced and tested under a deformation-controlled three-point bending test. Deformation maps on the surface of the specimens were derived through the digital image correlation method. Experimental results were discussed concerning the first cracking load, ultimate load, critical crack mouth opening displacement, critical crack mouth sliding displacement, and fracture energy. Based on the experimental findings, it can be stated that the peak flexural loads were increased by 666%, 1327%, and 400%, respectively for the 0, 0.2, and 0.4 notch offset ratios due to the use of recycled steel fiber. The fracture energies of the plain specimens were proportional to the notch offset ratio, but they fluctuated for the fiber-reinforced specimens because of the uneven distribution of fibers.