This paper aims to examine the effect of coal gangue aggregate (CGA), fly ash (FA), and ground-granulated blast slag (GGBS) on the rheological, mechanical and microstructure properties of concrete. The rheological properties, compressive strength, splitting tensile strength, flexural strength, and uniaxial tensile behaviour of coal gangue concrete (CGC) were determined, and the microstructure of the concrete mixtures were investigated by use of XRD and SEM analyses. The results revealed the action mechanism of CGA and mineral admixtures on the microstructure and macroscopic properties of CGC. FA first increased and then decreased the yield stress and plastic viscosity, while GGBS considerably increased the yield stress and plastic viscosity. Furthermore, a constitutive model was established for CGC containing FA and GGBS under compression. The proposed stress–strain model for CGC is accurate and can be used for nonlinear analysis of structures made of this type of concrete. Moreover, the addition of FA and GGBS consumes calcium hydroxide, but increases products such as hydrated calcium silicate aluminate. These findings elucidate the understanding and optimisation of CGA use in concrete production, while contributing to lowering carbon emissions.

中文翻译：

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粉煤灰和磨细高炉矿渣煤矸石混凝土的性能：流变性、力学性能和微观结构

本文旨在研究煤矸石骨料（CGA）、粉煤灰（FA）和磨细粒化高炉矿渣（GGBS）对混凝土流变、力学和微观结构性能的影响。测定了煤矸石混凝土（CGC）的流变性能、抗压强度、劈裂拉伸强度、弯曲强度和单轴拉伸性能，并通过 XRD 和 SEM 分析研究了混凝土混合物的微观结构。结果揭示了CGA和矿物掺合料对CGC微观结构和宏观性能的作用机制。 FA先增大后减小屈服应力和塑性粘度，而GGBS显着增大屈服应力和塑性粘度。此外，还建立了压缩下含有 FA 和 GGBS 的 CGC 本构模型。所提出的 CGC 应力-应变模型是准确的，可用于由此类混凝土制成的结构的非线性分析。而且，FA和GGBS的添加消耗了氢氧化钙，但增加了水合硅酸铝酸钙等产物。这些发现阐明了对 CGA 在混凝土生产中使用的理解和优化，同时有助于降低碳排放。