Department of Mechanical Engineering, Escola Superior de Tecnologia de Setúbal, Instituto Politécnico de Setúbal, 2910-761 Setúbal, Portugal.
Microsc Microanal. 2013 Oct;19(5):1222-30. doi: 10.1017/S1431927613001463. Epub 2013 May 15.
Several authors have reported the workability, mechanical properties, and durability of concrete produced with construction waste replacing the natural aggregate. However, a systematic microstructural characterization of recycled aggregate concrete has not been reported. This work studies the use of fine recycled aggregate to replace fine natural aggregate in the production of concrete and reports the resulting microstructures. The used raw materials were natural aggregate, recycled aggregate obtained from a standard concrete, and Portland cement. The substitution extent was 0, 10, 50, and 100 vol%; hydration was stopped at 9, 24, and 96 h and 28 days. Microscopy was focused on the cement/aggregate interfacial transition zone, enlightening the effect of incorporating recycled aggregate on the formation and morphology of the different concrete hydration products. The results show that concretes with recycled aggregates exhibit typical microstructural features of the transition zone in normal strength concrete. Although overall porosity increases with increasing replacement, the interfacial bond is apparently stronger when recycled aggregates are used. An addition of 10 vol% results in a decrease in porosity at the interface with a corresponding increase of the material hardness. This provides an opportunity for development of increased strength Portland cement concretes using controlled amounts of concrete waste.
几位作者已经报道了用建筑废料替代天然骨料生产的混凝土的工作性、力学性能和耐久性。然而，尚未有系统的再生骨料混凝土微观结构特征的报道。本工作研究了用细再生骨料替代细天然骨料生产混凝土，并报告了所得的微观结构。所用的原材料为天然骨料、从标准混凝土中获得的再生骨料和波特兰水泥。取代程度为 0、10、50 和 100 体积%；水化在 9、24、96 小时和 28 天停止。显微镜观察重点放在水泥/骨料界面过渡区，说明掺入再生骨料对不同混凝土水化产物的形成和形态的影响。结果表明，再生骨料混凝土表现出普通强度混凝土中过渡区的典型微观结构特征。尽管随着取代率的增加整体孔隙率增加，但使用再生骨料时界面粘结显然更强。添加 10 体积%会减少界面处的孔隙率，同时材料硬度相应增加。这为使用控制量的混凝土废料开发高强度波特兰水泥混凝土提供了机会。
