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Title |
Effects of Micro-Steel and Aramid Fibers on the Mechanical Properties and Toughness of a Crack-Healing Mortar
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Authors |
이기연(Ki-Yeon Lee) ; 양근혁(Keun-Hyeok Yang) |
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DOI |
https://doi.org/10.4334/JKCI.2025.37.4.473 |
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Keywords |
접합부 모르타르; 균열치유; 인성; 섬유보강 joint; mortar; crack healing; toughness; fiber reinforced |
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Abstract |
This study presents a preliminary investigation into the development of a crack-healing mortar for precast concrete joints, designed to enhance crack healing, control, and toughness. For the purpose of promoting crack-healing, 4 % of the mortar volume was replaced with an inorganic material and bacteria-based healing agent proposed by Yoon et al. (2022) and Lee et al. (2024). To improve tensile resistance and toughness, micro steel fiber content was varied from 0.25 % to 0.5 %, and aramid fiber content from 0.5 % to 0.75 % by volume. The compressive toughness index of the fiber-reinforced mortar was evaluated based on the stress?strain relationship in accordance with ASTM C1018. Flexural toughness was evaluated using both the flexural toughness index (per ASTM C1018) and the residual flexural strength values (as defined in fib Model Code 2010). Experimental results showed a crack-healing rate of 93 % at 28 days. Mortars reinforced with a hybrid combination of micro steel and aramid fibers exhibited the most ductile descending slopes in both the flexural load?displacement and flexural stress?CMOD (crack mouth opening displacement) relationship. Notably, compared to specimens reinforced with 0.5 % micro steel fibers alone, those incorporating a hybrid of 0.25 % micro steel fibers and 0.25 % aramid fibers exhibited higher residual flexural strength when crack widths exceeded 2.5 mm. These findings indicate that the proposed mortar design approach demonstrates good potential for application in precast concrete joints, offering improved crack-healing capacity and mechanical toughness.
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