The focus of this study is to investigate the effect of using coarse recycled concrete aggregates (RCAs) as an alternative material to natural coarse aggregate on the fresh, mechanical and durability behavior of concrete reinforced with steel fiber. Eighteen unique concrete mixes with RCA content of 0%, 50%, and 100% and steel fiber content of 0%, 1%, and 2% were prepared, and tests were performed to study slump, density, compressive and splitting tensile strengths, flexural behavior, surface hardness, surface abrasion resistance, water absorption, and sorptivity of each mix. It is shown that concrete containing RCA has a lower unit weight, compressive, splitting tensile and flexural strength, flexural toughness, surface hardness, and abrasion resistance, and a higher water absorption and sorptivity in comparison with conventional concrete. An increased compressive, splitting tensile and flexural strength, flexural toughness, surface hardness, and abrasion resistance, and a decreased water absorption and sorptivity of concrete with an increased steel fiber content from 1% to 2% is less significant compared to those from 0% to 1%. The results also show that, at RCA content of 50%, incorporating 1% steel fiber develops a concrete mix with similar or even better properties compared to unreinforced conventional concrete. At 100% RCA content, incorporating 2% steel fiber develops a concrete mix with similar properties to unreinforced conventional concrete having water to cement ratio of 0.3, but inferior properties to unreinforced conventional concrete having water to cement ratio of 0.5. These findings indicate that recycled aggregate concrete with similar or even better properties compared to concrete with natural aggregate can be developed through properly designing mixes, providing a great avenue toward the production of green construction material for structural applications.

中文翻译：

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含粗再生混凝土骨料的钢纤维混凝土的力学性能和耐久性能

本研究的重点是研究使用粗再生混凝土骨料 (RCA) 作为天然粗骨料的替代材料对钢纤维增强混凝土的新鲜、机械和耐久性行为的影响。制备了 18 种 RCA 含量为 0%、50% 和 100% 以及钢纤维含量为 0%、1% 和 2% 的独特混凝土混合物，并进行了测试以研究坍落度、密度、压缩和劈裂拉伸强度，弯曲行为、表面硬度、表面耐磨性、吸水率和每种混合物的吸附性。结果表明，与常规混凝土相比，含RCA的混凝土具有较低的单位重量、抗压、劈裂抗拉和抗弯强度、抗弯韧性、表面硬度和耐磨性，以及更高的吸水率和吸水率。与 0% 相比，钢纤维含量从 1% 增加到 2% 时，混凝土的抗压强度、劈裂强度和弯曲强度、弯曲韧性、表面硬度和耐磨性的增加以及混凝土吸水率和吸水率的降低不那么显着到 1%。结果还表明，在 50% 的 RCA 含量下，加入 1% 的钢纤维可开发出与未增强的常规混凝土相比具有相似甚至更好性能的混凝土混合物。在 100% RCA 含量下，加入 2% 钢纤维可开发出一种混凝土混合物，其性能与水灰比为 0.3 的无筋常规混凝土相似，但性能不如水灰比为 0.5 的无筋常规混凝土。