Flexural and Tensile Characteristics of Micro Fiber-reinforced Very High Strength Concrete Thin Panels

The purpose of this research was to experimentally characterize the flexural and tensile characteristics of fiber-reinforced Very High-Strength Concrete (VHSC) panels. The panels were made with a unique mix of cementitous materials achieving compressive strength of 26,000 psi (180 MPa) or greater. VHSC panels were reinforced with polypropylene fibers of 1 inch (25.4 mm) in length and Polyvinyl alcohol (PVA) micro-fibers of 1⁄2 inch length, incorporated at 1.5% by volume. For the flexural behavior, 17×2×3⁄4 inch flat panels were tested under third-point loading tests, while the direct tension experiments were tested on 10×3×1⁄2 inch tension panels under a direct tensile load. Flexural tests were conducted on three panels of plain VHSC, three panels of VHSC reinforced with polypropylene fibers and three panels of VHSC reinforced with 1⁄2 inch micro-fibers. Similar testing program was used to conduct the direct tension tests. Also, compression test conducted on 2×2×2 inch cubes and compressive test conducted on 4 inch by 8 inch cylinders test were used to establish compressive strength and modulus of elasticity respectively. Results show that the compressive strength, tensile strength and fracture toughness of the VHSC panels were much greater than those normally obtained by typical concrete material. The presence of fibers increases the toughness of VHSC specimens between 80 and 190% and increases the tensile strength by 23 to 47%. The modulus of elasticity and Poisson’s ratio recorded herein were determined according to ASTM C 469-02. Laboratory experiments on flexural and tensile properties of thin, very high-strength, fiber reinforced concrete panels, were used to study the material and characterize the panels’ reaction to load. Parameters such as compressive strength, tensile strength, toughness, elastic modulus, Poisson’s ratio and first-crack strength were determined and may be considered for potential use as design parameters in future material improvements.