CORRELATIONS BETWEEN COMPRESSIVE, FLEXURAL, AND TENSILE BEHAVIOR OF SELF-CONSOLIDATING FIBER REINFORCED CONCRETE

Abstract

Self-consolidating fiber reinforced concrete (SCFRC) is a hybrid concrete that is both self-compacting and fiber reinforced. Use of SCFRC in reinforced concrete members has been shown to result in improved behavior under shear, flexure, and compression relative to conventional reinforced concrete. The aim of this study was to investigate relationships between the compressive and tensile responses of SCFRC as well as relationships between measured compressive and flexural behavior. Such relationships would simplify characterization of the mechanical behavior of SCFRCs based on a relatively limited number of standard tests. A secondary objective was to quantify and report the effect of introducing different volume fractions of four types of steel fiber to SCCs with compressive strengths of 6 and 10 ksi. Four different hooked-end steel fibers were used in this study at volume fractions between 0.5% and 1.5%. Results showed that the post-peak slope in compression and the post-cracking flexural and tensile strengths all increased as fiber volume fraction increased, whereas properties up to development of cracking (or peak strength in the case of compression) were not affected by use of fibers. Among the parameters investigated, it was shown that the post-peak compressive response was most closely correlated with the post-crack peak strength in flexure and the flexural strength corresponding to a mid-span deflection of 0.04 in. It was also found that the within-batch coefficient of variation of post-crack peak tensile and flexural loads decreased significantly when T50 was at least 1.0 second, from an average of 40% to 13%. Of the fibers investigated, the RC-80/30-BP had the greatest impact on mechanical performance for a given volume fraction and the 3D RC-55/30-BG fiber had the least.