Basic Properties of SFRC Designed by the Binary Superposition Mix Proportion Method

Abstract

Test of basic properties of steel fiber reinforced concrete (SFRC) was carried out to further study the validity of the binary superposition mix proportion method. The strength grades of SFRC were CF40, CF50 and CF60. The key parameters of the study were the fraction of steel fiber by volume, the thickness of cement paste wrapping steel fibers and the water to cement ratio. The workability of fresh SFRC was measured firstly to satisfy the construction requirement. The compressive strength, tensile strength and flexural-tensile strength of SFRC were tested simultaneously. Based on the test data, the changes of above basic properties of SFRC are analyzed in view of the effects of the fraction of steel fiber by volume and the thickness of cement paste wrapping steel fibers. It shows that the optimum thickness of cement past wrapping steel fibers is 0.8mm. The influencing coefficients in formulas for calculating tensile strength and flexural-tensile strength of SFRC specified in the current technical specification are given out.