Abstract Strength development and shrinkage and creep behavior of recycled aggregate concrete as well as durability aspects such as carbonation and chloride ion penetration were investigated. Except for Control concrete, natural fine aggregate was replaced by recycled fine aggregate at a rate of 0%, 15%, 30%, or 50% while natural coarse aggregate was completely replaced by recycled coarse aggregate (RCA). Two different recycled fine aggregates were used: Recycled fine aggregate (RFA) and CO2 treated recycled fine aggregate (CRFA). Compressive strength of recycled aggregate concrete at all ages tested was reduced from that of the Control concrete. CO2 treatment of recycled fine aggregate improved not only the aggregate physical properties but also the strength of recycled aggregate concrete. The compressive strength reduction was 19% or less at 100% RCA + 15%–50% RFA replacement level while it was 11% or less at 100% RCA + 15%–50% CRFA replacement level after 28 days. Shrinkage and creep strains were measured for up to 300 days. Shrinkage of concrete with 100% RCA was 12% larger than that of Control concrete, while shrinkage of concretes with 100% RCA + 30% RFA or 30% CRFA replacement increased by about 25%–30%. In the creep test, creep coefficient and specific creep of all recycled aggregate concretes increased by about 20–35% over that of the Control. CO2 treatment of recycled fine aggregate resulted in up to 15% improved strength of recycled aggregate concrete, but showed little improvement on shrinkage and creep. Durability of recycled aggregate concrete evaluated in terms of carbonation and chloride ion penetration was reduced from that of the Control concrete.

中文翻译：

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混凝土的强度、收缩和蠕变以及耐久性方面，包括经过 CO2 处理的再生细骨料

摘要 研究了再生骨料混凝土的强度发展和收缩蠕变行为，以及碳化和氯离子渗透等耐久性方面。除对照混凝土外，天然细骨料以0%、15%、30%或50%的比例被再生细骨料替代，而天然粗骨料完全被再生粗骨料（RCA）替代。使用了两种不同的再生细骨料：再生细骨料 (RFA) 和 CO2 处理的再生细骨料 (CRFA)。所有测试年龄的再生骨料混凝土的抗压强度都低于对照混凝土的抗压强度。CO2 处理再生细骨料不仅提高了骨料的物理性能，而且提高了再生骨料混凝土的强度。28 天后，100% RCA + 15%–50% RFA 替代水平的抗压强度降低为 19% 或更低，而 100% RCA + 15%–50% CRFA 替代水平的抗压强度降低为 11% 或更低。测量收缩和蠕变应变长达 300 天。100% RCA 混凝土的收缩率比对照混凝土大 12%，而 100% RCA + 30% RFA 或 30% CRFA 替代的混凝土的收缩率增加了约 25%–30%。在蠕变试验中，所有再生骨料混凝土的蠕变系数和比蠕变比对照组增加了约 20-35%。CO2 处理再生细骨料可使再生骨料混凝土的强度提高 15%，但收缩和蠕变几乎没有改善。