Effects of basalt and glass chopped fibers addition on fracture energy and mechanical properties of ordinary concrete: CMOD measurement

• Chopped basalt and glass fibers with 24 mm lengths were used for producing of concrete specimens.
• Four different fiber contents (0.5, 1, 2 and 3 kg/m3) were selected for basalt and glass fiber reinforced concrete.
• Fracture energy and mechanical properties of basalt and glass fiber reinforced concrete were evaluated.
• Microstructures of the fiber reinforced concrete were investigated.

This study investigates fracture behavior of basalt fiber reinforced concrete (BFRC) and glass fiber reinforced concrete (GFRC) comparatively. For this purpose, three-point bending tests were carried out on notched beams produced using BFRC and GFRC with 0.5, 1, 2 and 3 kg/m3 fiber contents to determine the value of fracture energy. Fracture energies of the notched beam specimens were calculated by analyzing load versus crack mouth opining displacement (CMOD) curves by the help of RILEM proposal. In addition, microstructural analysis of the three components; cement paste, aggregate, basalt and glass fiber were performed based on the Scanning Electron Microscopy and Energy-Dispersive X-ray Spectroscopy examinations and analysis were discussed. The results showed that the effects of the fiber contents on fracture energy were very significant. The splitting tensile and flexural strength of BFRC and GFRC were improved with increasing fiber content whereas a slight drop in flexural strength was observed for high volume of fiber content. On the other hand, effect of fiber addition on the compressive strength and modulus of elasticity of the mixtures was insignificant.