The increasing demand for sustainable construction materials has driven significant interest in utilizing recycled concrete aggregates (RCA). However, the mechanical performance and durability of RCA are often compromised due to the presence of residual mortar. This study explores an innovative surface treatment approach combining abrasion and cement slurry coating to improve the properties of RCA and enhance the performance of recycled aggregate concrete (RAC). Recycled concrete aggregates were subjected to mechanical abrasion, followed by a cement slurry coating, resulting in the production of Surface-Treated Recycled Concrete Aggregates (STRCA). The study evaluates the impact of STRCA on the compressive strength, drying shrinkage, electrical resistivity, and chloride ion penetration resistance of concrete mixes with varying replacement ratios (25 %, 50 %, 75 %, and 100 %). Results revealed that the water absorption of RCA was significantly reduced from 5.35 % to 2.61 % following the treatment. STRCA 25 and STRCA 50 mixtures exhibited compressive strength increases of 30.16 % and 18.99 % at 7 days, and 29.37 % and 17.13 % at 28 days, respectively. Higher replacement levels (STRCA 75 and STRCA 100) resulted in strength reductions, with 3.91 % and 16.64 % decreases at 7 days. Drying shrinkage increased progressively with higher RCA content, showing 1.72 %, 10.91 %, 25.86 %, and 38.79 % increases at 28 days for STRCA 25, STRCA 50, STRCA 75, and STRCA 100, respectively. Electrical resistivity improved for lower replacement levels, with STRCA 25 showing a 3.41 % increase at 28 days, while STRCA 100 exhibited a 26.25 % reduction. The rapid chloride penetration test results showed that STRCA 100 had the highest resistance to chloride ion penetration, with a 22.72 % and 28.69 % increase in passed charge at 28 and 56 days, respectively, compared to the reference concrete. The findings indicate that surface-treated RCA can enhance the mechanical and durability properties of concrete, especially at lower replacement levels, making it a viable option for sustainable construction.

中文翻译：

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通过对再生混凝土骨料进行创新的磨损和水泥浆处理，提高混凝土的耐久性和强度


对可持续建筑材料的需求不断增长，推动了人们对利用再生混凝土骨料 （RCA） 的浓厚兴趣。然而，由于残留砂浆的存在，RCA 的机械性能和耐用性通常会受到影响。本研究探索了一种结合磨损和水泥浆涂层的创新表面处理方法，以改善 RCA 的性能并提高再生骨料混凝土 （RAC） 的性能。回收的混凝土骨料经过机械磨损，然后涂上水泥浆涂层，从而生产出表面处理的再生混凝土骨料 （STRCA）。该研究评估了 STRCA 对不同替代率（25 %、50 %、75 % 和 100 %）的混凝土混合物的抗压强度、干燥收缩率、电阻率和氯离子渗透阻力的影响。结果显示，处理后 RCA 的吸水率从 5.35 % 显着降低到 2.61 %。STRCA 25 和 STRCA 50 混合物在 7 天时抗压强度分别提高了 30.16 % 和 18.99 %，在 28 天时分别提高了 29.37 % 和 17.13 %。较高的更替水平 （STRCA 75 和 STRCA 100） 导致强度降低，7 天时分别降低了 3.91% 和 16.64 %。随着 RCA 含量的增加，干燥收缩率逐渐增加，STRCA 25、STRCA 50、STRCA 75 和 STRCA 100 在 28 天时分别增加了 1.72 % 、 10.91 % 、 25.86 % 和 38.79 %。电阻率在较低的更换水平下得到改善，STRCA 25 在 28 天时增加 3.41%，而 STRCA 100 减少 26.25%。氯离子快速渗透试验结果表明，STRCA 100 对氯离子渗透的抵抗力最高，分别为 22.72% 和 28。与参考混凝土相比，28 天和 56 天的通过费用分别增加了 69%。研究结果表明，表面处理的 RCA 可以提高混凝土的机械和耐久性，尤其是在较低的更换水平下，使其成为可持续建筑的可行选择。