Study on mechanical properties and damage characteristics of coal-based solid waste cemented backfill

• Published in: Construction & building materials Vol. 368; p. 130373
• Main Authors: Zhang, Jiqiang, Yang, Ke, He, Xiang, Zhang, Lianfu, Wei, Zhen, Zhao, Xinyuan, Fang, Juejing
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 03.03.2023
• Subjects: Coal-based solid waste cemented backfill; Damage evolution; Macroscopic deformation and failure; Mechanical properties; Probability density function; C-S-H; Damage evolution; Coal-based solid waste cemented backfill; UCS; Mechanical properties; Probability density function; SEM; XRD; Macroscopic deformation and failure; CBSWCB; AFt
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2023.130373

•The content of fly ash has the greatest influence on the early strength, and the concentration has the greatest influence on the later strength.•The macroscopic deformation and damage was gradually transformed from plastic and weak splitting damage to brittle and shear damage.•The damage was divided into Compression damage stage, rapid damage stage and Cumulative damage stage. In order to study the mechanical properties and damage evolution law of multi-source coal-based solid waste cemented backfill, the uniaxial compression, acoustic emission (AE) response and microstructure test experiments of coal-based solid waste cemented backfill (CBSWCB) were carried out. The mechanical evolution characteristics and macroscopic deformation and failure laws of CBSWCB under uniaxial compression are studied, the damage equation of CBSWCB based on probability density function is constructed, and the load-bearing damage evolution process of CBSWCB is quantitatively analyzed. The test results show that: 1) The uniaxial compressive strength of CBSWCB can be divided into three regions: low-increasing enhanced region, medium-strength stability zone, and high strength area. 2) The content of fly ash has the greatest influence on the early strength (3d) of CBSWCB, and the concentration has the greatest influence on the later strength (28d) of CBSWCB. 3) The macroscopic deformation and damage of CBSWCB under uniaxial compression was gradually transformed from plastic and weak splitting damage to brittle and shear damage. 4) The evolution of AE parameters of CBSWCB can be divided into rising period, calm period, active period and stable period, and the curve of cumulative AE ringing count shows an obvious “stepped” growth, with the cumulative ringing count increasing slowly in the rising period and stable period, increasing sharply in the active period and leveling off gradually in the stable period. 5) The damage of CBSWCB under uniaxial compression was divided into Compression damage stage, rapid damage stage and cumulative damage stage, and the damage variable gradually increases with the increase of curing age. Based on the damage model, it was further verified that the incomplete damaged residual structure of CBSWCB specimen still has a certain bearing capacity after reaching the peak stress.