Ruiz-Agudo Cristina, Cölfen Helmut
Physical Chemistry, Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany.
Chem Rev. 2024 Jun 26;124(12):7538-7618. doi: 10.1021/acs.chemrev.3c00259. Epub 2024 Jun 14.
Understanding the crystallization of cement-binding phases, from basic units to macroscopic structures, can enhance cement performance, reduce clinker use, and lower CO emissions in the construction sector. This review examines the crystallization pathways of C-S-H (the main phase in PC cement) and other alternative binding phases, particularly as cement formulations evolve toward increasing SCMs and alternative binders as clinker replacements. We adopt a perspective, which recognizes the existence of critical intermediate steps between ions in solution and the final crystalline phases, such as solute ion associates, dense liquid phases, amorphous intermediates, and nanoparticles. These multistep pathways uncover innovative strategies for controlling the crystallization of binding phases through additive use, potentially leading to highly optimized cement matrices. An outstanding example of in cementitious materials is the synthetically produced mesocrystalline C-S-H, renowned for its remarkable flexural strength. This highly ordered microstructure, which intercalates soft matter between inorganic and brittle C-S-H, was obtained by controlling the assembly of individual C-S-H subunits. While large-scale production of cementitious materials by a bottom-up self-assembly method is not yet feasible, the fundamental insights into the crystallization mechanism of cement binding phases presented here provide a foundation for developing advanced cement-based materials.
了解水泥结合相从基本单元到宏观结构的结晶过程，可以提高水泥性能、减少熟料用量并降低建筑行业的二氧化碳排放量。本综述研究了C-S-H（硅酸盐水泥的主要相）和其他替代结合相的结晶途径，特别是随着水泥配方朝着增加矿渣微粉（SCMs）和替代胶凝材料以替代熟料的方向发展。我们采用一种观点，即认识到溶液中的离子与最终结晶相之间存在关键的中间步骤，如溶质离子缔合物、致密液相、无定形中间体和纳米颗粒。这些多步途径揭示了通过使用添加剂来控制结合相结晶的创新策略，有可能产生高度优化的水泥基体。水泥基材料中一个突出的例子是合成的介晶C-S-H，它以其卓越的抗弯强度而闻名。这种高度有序的微观结构通过控制单个C-S-H亚基的组装，在无机且脆性的C-S-H之间嵌入了软物质。虽然通过自下而上的自组装方法大规模生产水泥基材料目前还不可行，但本文所阐述的对水泥结合相结晶机制的基本见解为开发先进的水泥基材料奠定了基础。
