Comparative ultimate tensile strength of concrete and fibre concrete

Abstract

The study is aimed at comparing the ultimate tensile stresses with respect to the crack resistance criteria of concrete and fibre concrete based on theoretical and experimental data. The resistance of concrete to cracking is determined by the ability to resist the formation and growth of cracks. According to the cracking resistance criterion, concrete deformations are limited by the ultimate tensile strength of the concrete matrix, insignificant for heavy concrete, and the introduction of dispersed reinforcement can significantly increase its tensile strength and crack resistance. Recommended methods for calculating the crack resistance of fibre concrete structures are based on the procedures, used to calculate the crack resistance of structures, reinforced with bars, and incompletely account the features of a fibre concrete as a structural material. In addition, although even a significant crack opening cause no effect on the bearing capacity of fibre concrete structures, generally accepted methods for calculating fibre concrete structures exclude cracking. The article discusses various options for calculating the ultimate tensile stresses of concrete and fibre concrete for ensuring crack resistance based on reference normative and experimental data. Dispersed reinforcement with metal fibres was established at least doubling the ultimate tensile strength according to the crack resistance criterion with even lowmodulus fibres effectively improving the crack resistance, which ensures a more reliable operation of structures, including during winter concreting.