Measuring Toughness Characteristics of SFRC--a Critical View of ASTM C 1018

American Society for Testing and Materials (ASTM) C1018, Standard Test Method for Flexural Toughness and First-Crack Strength of Fiber-Reinforced Concrete (Using Beam With Third-Point Loading), is conceived to produce toughness parameters independent of the dimensions of the test specimen. This concept appears to be false. In addition, the toughness indices that are required to be reported are shown not to be sensitive to the type and amount of fibers used, and thus do not provide a usable value for characterizing flexural toughness. Furthermore, since the computation of the toughness index values are directly related to the first-crack deflection measurements, a value which is difficult to determine, these values become dependent on the testing equipment used. Proposals for revision of ASTM C1018 are presented to address these concerns.