Influence of the use of corn straw fibers to connect the interfacial transition zone with the mechanical properties of cemented coal gangue backfill

• Published in: Construction & building materials 2023-02, Vol.367, p.130334, Article 130334
• Main Authors: Wang, Haochen, Feng, Guorui, Qi, Tingye, Gao, Xinyu, Wang, Chaoyu, Wang, Linfei, Zhang, Zhicheng
• Format: Article
• Language: English
• Subjects: Cemented coal gangue backfill; Corn straw fiber; Interfacial transition zone; Mechanical properties; Surface treatments
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2023.130334

[Display omitted] •Different treatments of corn straw fibers were prepared and tested.•A plant fiber reinforcement method aimed at ITZ was proposed.•The failure criterion of CCGB mixed with corn straw fiber was established.•The optimum corn straw fiber content for the mechanical properties of CCGB is 1 %–2 %. Cemented coal gangue backfill (CCGB) is a cement-based mixture containing coarse aggregates and is used to fill the goaves of underground coal mines. However, CCGB currently faces contradiction between its mechanical properties and material costs. Based on the technical idea of strengthening the weakest link of the mechanical properties (i.e., interface transition zone (ITZ)), a plant fiber reinforcement method for CCGB aimed at the ITZ was proposed. Moreover, using this method, aqueous-treated and alkaline-treated corn straw fibers, accounting for 1 %, 2 %, and 3 % of the mass of the coarse aggregate, were added to the CCGB. The effects of corn straw fibers on the uniaxial compressive strength, splitting tensile strength, shear strength, and drying shrinkage of CCGB were studied. The failure response characteristics of the specimen in the process of uniaxial compression were monitored using digital image correlation (DIC) and acoustic emission (AE) technology. The failure criterion of CCGB mixed with corn straw fiber was established based on the Mohr–Coulomb shear strength theory. The results demonstrated that adding 1 %–2 % corn straw fiber improved the mechanical properties of CCGB at an early age (before 28 days), but it was necessary to control the increase in drying shrinkage. The effect of alkaline treatment on corn straw fiber was better than that of aqueous treatment. This study will benefit the green development and resource utilization of solid biomass waste.