Abstract：
Low flexural strength and toughness have posed enduring challenges to cementitious materials. As the main hydration product of cement, calcium silicate hydrate (C-S-H) plays important roles in the mechanical performance of cementitious materials while exhibiting random microstructures with pores and defects, which hinder mechanical enhancement. Inspired by the \"brick-and-mortar\" microstructure of natural nacre, this paper presents a method combining freeze casting, freeze-drying, in situ polymerization, and hot pressing to fabricate C-S-H nacre with high flexural strength, high toughness, and lightweight. Poly(acrylamide-co-acrylic acid) was used to disperse C-S-H and toughen C-S-H building blocks, which function as \"bricks\", while poly(methyl methacrylate) was impregnated as \"mortar\". The flexural strength, toughness, and density of C-S-H nacre reached 124 MPa, 5173 kJ/m3, and 0.98 g/cm3, respectively. The flexural strength and toughness of the C-S-H nacre are 18 and 1230 times higher than those of cement paste, respectively, with a 60% reduction in density, outperforming existing cementitious materials and natural nacre. This research establishes the relationship between material composition, fabrication process, microstructure, and mechanical performance, facilitating the design of high-performance C-S-H-based and cement-based composites for scalable engineering applications.
摘要：
低抗弯强度和韧性对胶凝材料提出了持久的挑战。作为水泥的主要水化产物,水化硅酸钙(C-S-H)在胶凝材料的力学性能中起重要作用,这阻碍了机械增强。灵感来自天然珍珠质的“砖与砂浆”微观结构，本文提出了一种结合冷冻铸造的方法，冷冻干燥,原位聚合,并进行热压，以制造具有高抗弯强度的C-S-H珍珠质，高韧性，和轻量级。聚（丙烯酰胺-共-丙烯酸）用于分散C-S-H和增韧C-S-H结构单元，它的功能是“砖块”，而聚(甲基丙烯酸甲酯)浸渍为“砂浆”。抗弯强度,韧性,C-S-H珍珠母密度达到124兆帕，5173kJ/m3和0.98g/cm3。C-S-H珍珠质的抗弯强度和韧性分别是水泥浆的18倍和1230倍,分别,密度降低了60%,优于现有的胶凝材料和天然珍珠层。本研究建立了材料成分之间的关系，制造工艺,微观结构，和机械性能，促进高性能C-S-H基和水泥基复合材料的设计，用于可扩展的工程应用。
