Initiation and Fracture Characteristics of Different Width Cracks of Concretes under Compressional Loading

Applied Sciences

Bu Li¹  Lizhou Wu²  Jianting Zhou²  Jingzhou Xin²  Hong Zhang²  Jun Yang² 

[1] China Southwest Geotechnical Investigation & Design Institute Co., Ltd., Chengdu 610052, China;State Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing Jiaotong University, Chongqing 400074, China;

关键词: crack;    concrete material;    uniaxial compression;    strength;    mixed-mode fracture criterion;   

DOI  :  10.3390/app12104803

来源: DOAJ

【 摘 要 】

A stress concentration at a crack tip may cause fracture initiation even under low-stress conditions. The maximum axial stress theory meets the challenges of explaining the fracture propagation of a non-closed fracture of cracked concretes under compressional loading. Uniaxial loading tests of single-crack concrete specimens were carried out and a numerical simulation of fracture propagation under uniaxial compression was performed. The radial shear stress criterion for a mode-II fracture is proposed to examine the stress intensity factor (SIF) of the pre-crack specimens under compressional loading. When the maximum radial shear stress at the crack tip is larger than the maximum axial tensile stress, and the maximum dimensionless SIFs can satisfy f_rθmax/f_θmax > 1 and f_rθmax/f_θmax > K_IIC/K_IC ($f_{\theta \max }=K_{\mathrm{Ie}}/{\sigma }_y^{}\sqrt{\pi a}$ and $f_{r\theta \max }=K_{\mathrm{II}\mathrm{e}}/{\sigma }_y^{}\sqrt{\pi a}$ are maximum dimensionless mode-I and mode-II SIFs, respectively), the crack will extend along the direction of the maximum radial shear stress. The influence of the single-crack angle and width on the mechanical properties of the specimens was examined. The experimental and numerical results indicate that the existence of cracks can considerably weaken the strength of the specimen. The distribution and width of the cracks had a significant effect on the specimen strength. The strength of the concrete specimen initially decreased and then increased with increasing fracture angle. The failure mechanism and rupture angle of pre-crack brittle material while considering crack width will be discovered.

【 授权许可】

Unknown