Strain-hardening cementitious composites (SHCCs) are durable, ductile, fiber-reinforced cement-based materials. While fly ash (FA) is often used to partially replace Portland cement in SHCCs to enhance material performance, it can lead to long setting times and slow strength development. To address these limitations, this study investigates the use of aluminate cement as partial replacements for Portland cement in FA-based SHCCs. Furthermore, the study aims to fill a significant knowledge gap by thoroughly examining the influence of aluminate cement on the workability, durability, and strain-hardening behavior of SHCCs. Aluminate cements encompass both calcium sulfoaluminate (CSA) cement and calcium aluminate cement (CAC), distinguished by their composition rich in calcium aluminate phases. This study investigated the use of CSA and CAC cements as partial replacements for Portland cement in SHCCs. Both fresh and hardened properties of the CSA- and CAC-SHCCs were examined, while their microstructures and chemical phases were investigated using SEM and XRD analyses. Results showed that CSA and CAC cements reduced fluidity, setting time, and drying shrinkage but increased porosity and early strength development for SHCCs. CSA-SHCCs showed enhanced impermeability due to the refinement of interior pore space through the hydration products. While all modified SHCCs retained tensile strain hardening behavior, the tensile performance degraded due to the hydration effects of ye'elimite and calcium aluminates. The reduced tensile strain capacity was elucidated using the theory of steady-state crack opening.

中文翻译：

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铝酸盐水泥对应变硬化水泥基复合材料耐久性和力学性能的影响

应变硬化水泥基复合材料 (SHCC) 是耐用、延展的纤维增强水泥基材料。虽然粉煤灰 (FA) 通常用于部分替代 SHCC 中的波特兰水泥以提高材料性能，但它可能导致凝结时间长且强度发展缓慢。为了解决这些局限性，本研究研究了在 FA 基 SHCC 中使用铝酸盐水泥作为波特兰水泥的部分替代品。此外，该研究旨在通过彻底研究铝酸盐水泥对 SHCC 的和易性、耐久性和应变硬化行为的影响来填补重大知识空白。铝酸盐水泥包括硫铝酸钙（CSA）水泥和铝酸钙水泥（CAC），其特征在于其成分富含铝酸钙相。本研究调查了在 SHCC 中使用 CSA 和 CAC 水泥作为波特兰水泥的部分替代品。对 CSA-和 CAC-SHCC 的新鲜和硬化性能进行了检查，同时使用 SEM 和 XRD 分析研究了它们的微观结构和化学相。结果表明，CSA 和 CAC 水泥降低了 SHCC 的流动性、凝结时间和干燥收缩，但增加了孔隙率和早期强度发展。由于水化产物细化了内部孔隙空间，CSA-SHCC 表现出增强的抗渗性。虽然所有改性 SHCC 都保留了拉伸应变硬化行为，但由于 ye'elite 和铝酸钙的水合效应，拉伸性能下降。使用稳态裂纹张开理论阐明了降低的拉伸应变能力。