Effect of confining pressure on shear resistance of ultra-high-performance fiber reinforced concrete

Abstract

Effect of confining pressure on the shear resistance of ultra-high-performance fiber-reinforced concrete (UHPFRCs), containing 1.5% volume content (1.5 vol.-%) of short smooth steel fiber (SS, l = 13, d = 0.2 mm) and long smooth steel fiber (LS, l = 30, d = 0.3 mm), was investigated using a new shear test method. Three levels of confining pressure were generated and maintained to the longitudinal axis of the specimen prior shear loading was applied. The test results exhibited that the shear strength of UHPFRCs was obviously sensitive to the confining pressure: the higher confining pressure produced higher shear strength. UHPFRC reinforced with 1.5 vol.-% long smooth steel fiber exhibited higher shear resistance than those reinforced with short smooth steel fiber, regardless of confining pressure levels. The confined shear strength could be expressed as an empirical function of unconfined shear strength, confining pressure, and tensile strength of UHPFRCs.

Keywords:

UHPFRCs, shear resistance; confining pressure effect; smooth fiber.