The large-scale recycling of concrete waste and its high-value utilization are key research topic in the field of sustainable building materials. This paper investigated the properties of fully recycled mortar made with thermoactivated recycled cement and recycled fine aggregate (RFA) up to 100%. The 600 °C thermoactivated recycled cement contained active compounds such as CS and CaO. Substituting recycled cement for ordinary Portland cement reduced the hydration reaction and enlarged the pore structure of paste, but mixing active admixture could improve the micro-structure of recycled cement paste. Incorporating recycled cement and RFA decreased the mechanical strength of mortar, as well as elevated the drying shrinkage and transport properties. The detrimental impact of incorporating recycled cement on the performance degradation was more prominent than that of RFA incorporation. Nevertheless, the properties of fully recycled mortar with both 100% recycled cement and RFA still achieved a relatively satisfactory level. Besides, recycled mortar made with recycled cement derived from cement paste waste exhibited superior performance to that made with recycled cement from concrete waste. Substituting active admixture for 10% recycled cement could obviously improve the strength and permeability resistance of fully recycled mortar. Therefore, optimizing the replacement rate of recycled cement, RFA and active admixture is expected to prepare the fully recycled mortar with good performance. The maximal utilization of concrete waste could be achieved through preparing fully recycled mortar with the use of recycled cement and RFA completely instead of natural sand and ordinary Portland cement. This approach resulted in lower CO emissions and provided superior environmental benefits.

中文翻译：

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结合使用100%热活化再生水泥和再生骨料制备全再生砂浆：性能评估和改性

混凝土废弃物的大规模回收及其高值化利用是可持续建筑材料领域的重点研究课题。本文研究了由热活化再生水泥和再生细骨料 (RFA) 制成的完全再生砂浆的性能，最高可达 100%。 600℃热活化再生水泥含有活性化合物，如CS和CaO。用再生水泥替代普通硅酸盐水泥，减少了水化反应，增大了浆体的孔隙结构，但掺入活性外加剂可以改善再生水泥浆体的微观结构。掺入再生水泥和 RFA 降低了砂浆的机械强度，并提高了干燥收缩和运输性能。掺入再生水泥对性能下降的不利影响比掺入 RFA 更为突出。尽管如此，100%再生水泥和RFA的全再生砂浆的性能仍然达到了相对令人满意的水平。此外，用水泥浆废料中的再生水泥制成的再生砂浆表现出优于用混凝土废料中的再生水泥制成的再生砂浆的性能。用活性外加剂代替10%再生水泥可明显提高全再生砂浆的强度和抗渗性能。因此，优化再生水泥、RFA和活性外加剂的替代率有望制备出性能良好的全再生砂浆。采用再生水泥和RFA完全替代天然砂和普通硅酸盐水泥制备全再生砂浆，可以实现混凝土废料的最大化利用。这种方法降低了二氧化碳排放量，并提供了卓越的环境效益。