Abstract
To solve the problem on the serious loss of bond strength of shotcrete in hot and dry environments, the measures for improving the bond strength were explored by mixing mineral admixtures or fiber materials into shotcrete mixture. The bond strengths between shotcrete and rock in hot and dry environments were measured by splitting method, and macroscopic, mesoscopic and microscopic analyses were carried out on shotcrete specimens. The results show that: in hot and dry environments, the bond strengths all decrease when mixed with mineral admixtures, and especially for the fly ash, with which the bond strength of shotcrete decreases by 36.7%. Mixing polypropylene fibers into shotcrete makes its bond strength decrease by 10.2%, but for steel fibers, it will be improved by 41.8% compared with basic mix proportion. Moreover, according to submicroscopic measurement and microscopic analysis, the influence mechanisms of mineral admixtures and fiber materials have been explored to some extent. Therefore, it’s feasible and effective to improve the bond strength by adding steel fibers in hot and dry environment.
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Cui, S., Xu, D., Liu, P. et al. Exploratory study on improving bond strength of shotcrete in hot and dry environments of high geothermal tunnels. KSCE J Civ Eng 21, 2245–2251 (2017). https://doi.org/10.1007/s12205-016-0901-y
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DOI: https://doi.org/10.1007/s12205-016-0901-y