Quantification of cracking localization in fibre-reinforced concrete beams

FIBRE CONCRETE 2017

Werzbrger, S.^1 ; Karinski, Y.S.^2 ; Dancygier, A.N.^1,2

Faculty of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Technion City, Haifa

32000, Israel^1

National Building Research Institute, Technion - Israel Institute of Technology, Technion City, Haifa

32000, Israel^2

关键词: Fibre content;    Fibre reinforced concrete;    Flexural cracks;    Flexural ductility;    Localization phenomena;    Low reinforcement ratios;    Reinforcement ratios;    Structural elements;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/246/1/012024/pdf
DOI  :  10.1088/1757-899X/246/1/012024

来源: IOP

【 摘 要 】

The paper presents an analysis of cracking localization in beams made of fibre-reinforced concrete with conventional reinforcement. This phenomenon has been quantified by the ratio m/n between the number of the significantly wide cracks and the total number of flexural cracks that developed within the constant moment zone of the beams. It is shown that beams with larger reinforcement ratio had larger values of m/n, that is, lower cracking localization. For the given concrete mix, when the reinforcement ratios ρ were larger than ∼2% cracking localization was diminished. Furthermore, for low values of ρ, m/n ratios of the specimens with lower fibre contents are somewhat larger than those of the specimens with larger content. It is also shown that as the reinforcement ratio decreases below ∼0.5% the normalized mid-span ultimate deflections decreases as well, which corresponds with the observation of the cracking localization phenomenon for low reinforcement ratios. For larger reinforcement ratio, when m/n increases above ∼0.6, there is no effect of cracking localization on the ultimate deflection. Moreover, in this range of r the values of d are 1.0, as commonly expected for RFC structural elements. It is noted that the ultimate deflection of the beams corresponds to their flexural ductility.