Abstract

A sustainable Self-Compacting Concrete (SCC) was proposed by replacing natural aggregates with recycled coarse aggregates (RCAs) and cement with supplementary cementitious materials (SCMs). A total of 23 SCC mixes, including binary, ternary and quaternary mixes were prepared with three water to binder ratios (0.35, 0.40, and 0.45) and two RCA replacement levels (50%, 100%) as well as two SCM replacement levels (50%, 75%). The fresh state properties, in terms of filling ability, passing ability, viscosity and segregation resistance were studied as well as the hardened state properties. The effect of RCAs and SCMs on the fresh and hardened state properties of SCC mixes was analyzed as well as the influence of using a combination of fly ash, slag and/or silica fume. The test results indicate that SCC incorporating RCAs and SCMs exhibited superior workability and comparable compressive strength and the combination of fly ash, slag and silica fume can compensate for the detrimental effect of RCAs and increase the compressive strength. Thus, the content of RCAs and SCMs can be maximised by using a combination of fly ash, slag and silica fume, which will optimise the sustainability aspect of SCC mixes by minimising cement and nonrenewable natural resources content.

摘要

提出了一种可持续的自密实混凝土 (SCC)，用再生粗骨料 (RCA) 代替天然骨料，用辅助胶凝材料 (SCM) 代替水泥。共制备了 23 种 SCC 混合物，包括二元、三元和四元混合物，其中三种水与粘合剂的比率（0.35、0.40 和 0.45）和两种 RCA 替代水平（50%、100%）以及两种 SCM 替代水平（ 50%、75%）。研究了新鲜状态特性，包括填充能力、通过能力、粘度和抗离析性以及硬化状态特性。分析了 RCA 和 SCM 对 SCC 混合物的新鲜和硬化状态特性的影响，以及使用飞灰、矿渣和/或硅灰组合的影响。测试结果表明，加入 RCA 和 SCM 的 SCC 表现出优异的可加工性和相当的抗压强度，飞灰、矿渣和硅灰的组合可以弥补 RCA 的不利影响并提高抗压强度。因此，RCA 和 SCM 的含量可以通过使用飞灰、矿渣和硅灰的组合来最大化，这将通过最大限度地减少水泥和不可再生自然资源的含量来优化 SCC 混合物的可持续性方面。