Prediction models of compressive mechanical properties of steel fiber-reinforced cementitious composites (SFRCC)

Steel fiber reinforced cementitious composites (SFRCCs), including normal strength concrete (NSC), high strength concrete (HSC), and ultra-high performance concrete (UHPC), have attracted significant attention in research and commercial applications due to their excellent mechanical properties and durability. The compressive performance of concrete reflects the maximum stress that the material can withstand under applied loading, which directly affects the safety and bearing capacity of buildings and is a very important parameter in the design and construction of buildings. Many researchers have experimentally studied the mechanical properties of SFRCC under uniaxial compression and proposed models to predict the compressive properties, such as compressive strength, elastic modulus, and peak strain. However, the test results and quantitative assessment of the existing models in the literature indicate that the goodness of fit of existing models is not well enough. Even under their specific range given in the respective studies, the maximum values of correlation coefficient in regression analysis, R2, are 14.5 % for compressive strength, 36.0 % for elastic modulus, and 42.1 % for peak strain. In addition, the scope of application is not wide enough as soon as the influencing factors considered are not sufficient. This makes that the compressive properties of SFRCC cannot be accurately predicted. In order to overcome these limitations, compression tests on UHPC were conducted in this study, focusing on the most commonly used straight steel fibers (13 mm long and 0.2 mm diameter). Further, modified models for predicting compressive properties were proposed using test data from this study and existing publications, with the R2 of 46.7 % for compressive strength, 48.1 % for elastic modulus, and 48.4 % for peak strain. The new models showed higher accuracy and applicability in predicting SFRCC compressive properties.