海水拌养混凝土固-液界面非匀质溶解动力学过程和水化时变规律

Seawater mixing concrete technology is one very important way to accelerate the construction of offshore projects and realize the marine resources utilization. Yet the hydration mechanism of cementitious materials under the coupling of multiple inorganic salts contained in seawater and the wide span of temperature still remains unclear. This project will be the first time to apply Digital Holographic Microscopy on characterizing the 3D topography at the solid-solution interface on nano-scale in real time and in situ. The solid-solution interface dissolution rate distribution will be quantitatively characterized, the time dependent growth of hydration products will be revealed under the coupling effect of multiple salts and temperature. Based on the heterogeneous dissolution behavior, the hydration kinetic model will be developed. The microstructure will also be investigated, based on which the 3D thermodynamic microstructure model will be established. Therefore, the hydration mechanism and microstructure development of cementitious materials under the coupling of multiple salts and temperature will be revealed essentially. This study will provide the theoretical support for the optimization of seawater mixing concrete durability in the future.

海水拌养混凝土技术是实现海洋地材资源化，加速海洋离岸工程建设的重要途径。然而，海水中多盐-温度耦合作用下的水化机理却不明确。本项目将率先运用数字化全息显微技术，纳米尺度上实时、原位监测胶凝材料纳米尺度上的三维形貌变化，定量表征固-液界面溶解速率的分布，揭示多盐-温度交互作用下胶凝体系水化产物生长的时变规律，建立基于胶凝材料非匀质溶解的水化动力学模型。探明微结构的形成与演变过程，建立基于热动力学的3D微结构演化模型。进而，从源头上阐明多盐-温度耦合作用下胶凝材料的水化机理和微结构演变机制，为优化海水拌养混凝土的长期服役性能提供重要的理论依据。

海水拌养混凝土技术是实现海洋地材资源化和加速海洋离岸工程建设的重要途径，而海水中氯离子和硫酸根等离子对钢筋混凝土耐久性的危害行为有待进一步探明和抑制。本项目针对水泥基材料在盐离子环境下的溶解行为和水化时变规律，利用数字化全息显微镜技术监测了水泥重要矿物铝酸三钙在纯水和盐溶液中的溶解行为差异，克服了传统方法无法准确测量高活性水泥矿物纯溶解速率的局限性，同时也证实了硫酸根离子对抑制铝酸三钙早期溶解的作用机理。项目组研究了海水无机盐对水泥体系的水化作用机理及水泥浆体早期性能的影响，探明了海水无机盐对于水化进程、水化产物种类及形貌以及浆体流变性能和力学性能的影响规律，进一步分析研究了海水拌养技术的适用性。