Abstract

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Title:: Experiment on Flexural Toughness of Synthetic Macrofiber Reinforced Reactive Powder Concrete

Author(s):: JIA Fang-fang; HE Kui; AN Ming-zhe; WANG Er-po; LU Zhen-bao; School of Civil Engineering, Beijing Jiaotong University

Keywords:: synthetic macrofiber; reactive powder concrete; flexural toughness; toughness index; residual intensity

Abstract:: In order to evaluate the flexural toughness of synthetic macrofiber reinforced reactive powder concrete, beam specimens were tested under four points flexural method. The contents of synthetic macrofiber were 4.75，9.5，14.25，19 kg·m-3, respectively, and plain reactive powder concrete specimens without fiber were analyzed in contrast. The results show that plain reactive powder concrete specimens without fiber are brittleness, specimens breakdown when the crack is appeared, and the descending branch of loaddeflection curves cannot be collected. While the failure mode of specimens with synthetic macrofiber is ductility and a steady descending branch of loaddeflection curves is collected. At the same time, the curves all have two peaks, presenting the phenomenon of secondary reinforcement. This means that synthetic macrofiber can improve the flexural toughness of reactive powder concrete. Descending branch of loaddeflection curves is flatter and toughness index with the increasing of fiber content. The residual intensity is above 85% of flexural strength when the fiber content (volume fraction) is 1.0%2.0%, which indicates that synthetic macrofiber has excellent crack resistance, and can improve the ductility of bendingtension specimens after cracking.