Wang Shuping, Peng Xiaoqin, Tang Luping, Cao Chunpeng, Zeng Lu
College of Materials Science and Engineering, Chongqing University, Chongqing 400045, China.
Department of Architecture and Civil Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden.
Materials (Basel). 2018 Nov 25;11(12):2367. doi: 10.3390/ma11122367.
Calcium silicate hydrate (C-S-H) synthesized by a hydrothermal process from lime and siliceous materials was oven-dried and compressed into compacts. The microstructure and compaction properties of the resulting powders were characterized. The results show that the powders containing an amorphous structure become hardened compacts immediately after compression. Compacts with high strength but a relatively lower bulk density were produced. Amorphous C-S-H plays a key role in the bonding formation during powder compaction. According to the Heckel plots, particle rearrangement and plastic deformation were involved in the compaction of C-S-H powders. Point contact between C-S-H particles due to particle rearrangement dominates at a low compression pressure (i.e., <20 MPa). Van der Waals forces and hydrogen bonding are the main bonding types. Plastic deformation occurs at a higher compression pressure (i.e., >60 MPa), which results in surface contact. Consequently, a solid bridge forms, and the strength of compacts increases rapidly. These findings provide novel insight into the utilization of materials containing amorphous calcium silicate hydrate.
通过水热法由石灰和硅质材料合成的硅酸钙水合物（C-S-H）经烘干后压缩制成坯块。对所得粉末的微观结构和压实性能进行了表征。结果表明，含有无定形结构的粉末在压缩后立即变成硬化坯块。制备出了具有高强度但堆积密度相对较低的坯块。无定形C-S-H在粉末压实过程中的粘结形成中起关键作用。根据赫克尔图，C-S-H粉末的压实涉及颗粒重排和塑性变形。在低压缩压力（即<20 MPa）下，由于颗粒重排导致C-S-H颗粒之间的点接触占主导。范德华力和氢键是主要的键合类型。在较高压缩压力（即>60 MPa）下发生塑性变形，导致表面接触。因此，形成了固体桥，坯块强度迅速增加。这些发现为含无定形硅酸钙水合物材料的利用提供了新的见解。
