Tension stiffening behaviors of reinforced ultra-high performance concrete

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This study aims to analyze the various fiber volume fractions (1%, 2% and 3%) and reinforcement diameters (16, 18 and 20 mm) on the tension stiffening mechanisms and effect of ultra-high performance concrete (UHPC) through the axial tensile test of reinforced UHPC (RUHPC). The results reveal that the tensile response of RUHPC can be categorized into four stages: elastic, cracking, crack development and post-yield. Both fiber volume fraction and reinforcement diameter significantly influence crack development and distribution, with distinct patterns observed in cracking load, equivalent stiffness, yield capacity, and toughness. The study further analyzes the mechanisms by which fiber volume fraction and reinforcement diameter affect the tension stiffening of RUHPC at various stages. Additionally, a tension stiffening characterization model and a UHPC tensile constitutive model were proposed, effectively predicting the tension stiffening behavior of UHPC materials and components under varying fiber volume fractions and reinforcement diameters.