Analysis of material size and shape effects for steel fiber reinforcement self-consolidating concrete

摘要

An experimental program is conducted in this study to evaluate the specimen shape and size effects on the compressive strength of steel fiber reinforced self-consolidating concrete (SFRSCC). The results of fresh and hardened concrete properties are first examined through casting cubic specimens in five different sizes and three sizes of cylindrical specimens with a height-to-diameter ratio of 2. The shape-effect model is then evaluated and the coefficients are obtained. Furthermore, relations between cubic and cylindrical specimens are presented and suggestions for the practical cases are offered. Subsequently, the size effect models SEL, MSEL, MFSL, USEL, and the model proposed by Sim et al. are discussed and the coefficients for self-consolidating concrete (SCC) and SFRSCC are updated. Moreover, cubic and cylindrical specimens are compared regarding crack pattern. The results clearly express that with the increase of steel fibers, the size effect is decreased and the structure becomes more ductile. The size effect in cubes is more pronounced than that of the cylinder. By adding and increasing the steel fiber content, the size effect decreased owing to crack bridging and the reduction of crack growth. Also, failure moves towards the strength criteria region in the SEL and towards the Euclidian regime in the MFSL.