This article aims to study the effects of adding steel fibers and galvanized recycled spring on mechanical properties and crack development in the fine-grained concrete exposed to the acidic environment containing magnesium sulfate. To this end, specimens containing 0.3% and 0.6% of steel fibers and springs, respectively, by concrete volume, were built in normal temperature using 10 cm × 20 cm standard steel formworks so as to conduct the compressive and tensile strength tests. All specimens were cured in 28 days exposed to the environment containing 0%, 5%, and 10% of magnesium sulfate. Based on the results, addition of steel fibers and recycled spring improves the compressive and tensile strength by 50% and 60%, respectively. Moreover, the specimens containing recycled spring better withstood against the acidic environments in comparison with the specimens including steel fibers. In general, it was found that due to the negligible difference between the strength of the specimens, the application of metal-recycled spring in the fine-grained concrete is technically and economically justifiable.

中文翻译：

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掺有再生钢弹簧的细粒混凝土在酸性条件下的性能试验研究

本文旨在研究添加钢纤维和镀锌再生弹簧对暴露在含硫酸镁酸性环境中的细粒混凝土力学性能和裂缝发展的影响。为此，在常温下使用 10 cm × 20 cm 标准钢模板建造混凝土体积分别含有 0.3% 和 0.6% 钢纤维和弹簧的试件，以进行抗压和抗拉强度试验。所有样品均在暴露于含有 0%、5% 和 10% 硫酸镁的环境中 28 天后固化。根据结果​​，钢纤维和再生弹簧的添加分别提高了 50% 和 60% 的压缩和拉伸强度。而且，与含有钢纤维的试样相比，含有再生弹簧的试样能更好地耐受酸性环境。总的来说，发现由于试件强度之间的差异可以忽略不计，金属再生弹簧在细粒混凝土中的应用在技术和经济上都是合理的。