An investigation of the toughness and compressive toughness index of steel fiber reinforced concrete.

In this paper, various methods for determining the toughness of steel fiber reinforced concrete (SFRC) are compared and evaluated using five criteria. The ASTM C1018-85 method mostly conforms to these criteria and, hence, is accepted as the foundation for China's standard test method of compressive toughness of SFRC. It is proposed that the critical-load point replace the first-crack point in defining the compressive toughness index based on an analysis of the onset and propagation of cracks in concrete under uniaxial compressive loading. The transient coefficient for load-carrying capacity is also given to indicate the variational characteristic of toughness. Experiments were carried out to verify the validity of the recommended index.