MNNIT Allahabad, Prayagraj, U.P, India.
Environ Sci Pollut Res Int. 2022 Aug;29(36):54167-54180. doi: 10.1007/s11356-022-19638-5. Epub 2022 Mar 16.
In this experimental study on self-compacting concrete (SCC), the Manufactured sand (M-sand) and Fly ash (FA) were utilised for partial replacement of Natural sand (N-sand) and Ordinary Portland Cement (OPC), respectively. N-sand was partially replaced by M-sand at various percentage levels, after the dose of FA in the mix was optimised. In terms of compressive strength, the optimum replacement level of OPC by FA was 20%, whilst for replacement of N-sand by M-sand it was 50%. Two types of mixes were prepared to compare the macro and micro level properties of SCC, i.e., SCC-I (100%OPC + 100%N-sand) and SCC-II (80%OPC + 20%FA + 50%N-sand + 50%M-sand). The characteristics of fresh concrete mixes were determined using Slump flow, T time, V-funnel, L-box, U-box, and J-ring tests. After 28 days of curing in tap water, both types of specimens were exposed to a solution of ammonium sulphate [(NH)SO] containing sulphate salt concentration of 2.0 g/l for 360 days to test their durability. Loss in compressive strength, weight change, sorptivity, and micro-structural changes (XRD, SEM, and EDS) all were evaluated for up to 360 days. It was found that the use of FA and M-sand in concrete makes it more environmental-friendly and durable, as well as have better performance in a sulphate environment.
在这项自密实混凝土（SCC）的实验研究中，利用机制砂（M-sand）和粉煤灰（FA）分别替代天然砂（N-sand）和普通波特兰水泥（OPC）的部分用量。在优化了混合中的 FA 剂量后，N-sand 被 M-sand 以不同的百分比替代。就抗压强度而言，FA 替代 OPC 的最佳替代水平为 20%，而 N-sand 替代 M-sand 的最佳替代水平为 50%。制备了两种类型的混合物来比较 SCC 的宏观和微观特性，即 SCC-I（100%OPC + 100%N-sand）和 SCC-II（80%OPC + 20%FA + 50%N-sand + 50%M-sand）。使用坍落度流动度、T 时间、V 漏斗、L 箱、U 箱和 J 环试验来确定新拌混凝土混合物的特性。在自来水养护 28 天后，将两种类型的试件分别暴露在含有 2.0g/l 硫酸盐盐浓度的硫酸铵[(NH)SO]溶液中 360 天，以测试其耐久性。直至 360 天，评估了抗压强度损失、重量变化、吸水性和微观结构变化（XRD、SEM 和 EDS）。结果发现，在混凝土中使用 FA 和 M-sand 可使其更环保、更耐用，并且在硫酸盐环境中具有更好的性能。
