Synthesis and Multi-Scale Mechanical Characterization of CSH

本研究旨在了解作为水泥主要水化产物的硅酸钙(C-S-H)的性质及其在水泥基复合材料强度和断裂中的作用。最近墨西哥湾油井破裂及其对环境的影响要求我们彻底了解水泥养护制度的重要性，包括高压和高温对水泥水化产物微观结构的影响，以及这种微观结构对水泥的力学、冲击和抗断裂性能的影响。本研究的目的是探索C-S-H的合成基本工艺，关联其纳米和微观结构特征，进一步了解其蠕变、冲击强度和断裂韧性等力学性能。范围集中在改变硅酸钙(C/S)比例(C/S比例从0.6%到1.5%)以及在不同的温度和压力组合下发生水化过程时，C-S-H的纳米和微观结构特征如何改变。通过对不同养护条件下合成的C-S-H的测试，了解水化条件对C-S-H的硅酸盐聚合和水结构的影响，以及C-S-H的纳米结构对其蠕变、断裂和冲击强度的影响。资金将用于支持新墨西哥大学(UNM)的研究生和本科生：这是一所为少数族裔服务的机构。这项工作将填补一个重大的知识空白，因为大多数在该领域工作的研究人员都集中在C-S-H的化学和微观结构性质上，而关于C-S-H的力学特性的研究非常有限。如果成功，我们将揭示C-S-H的一些主要力学特性，包括蠕变、断裂和冲击强度。成功的研究调查将导致水泥制造业产生必要的变化，以生产耐冲击的水泥基复合材料。

This research project aims at understanding the nature of calcium-silicate-hydrate (C-S-H) as the main cement hydration product and its responsibility in the strength and fracture of cement based composites. The recent fracture of oil well in the Gulf of Mexico and its associated environmental impact necessitate a thorough understanding of the significance of cement curing regimes, including high pressure and temperature on the microstructure of cement hydration products and the influence of that microstructure on the mechanical, impact and fracture resistance of cement. The goal of the research is to investigate the fundamental process for synthesis of C-S-H, to correlate its nano and microstructure features, and to further understand its mechanical characteristics including creep, impact strength and fracture toughness. The scope focuses on how the nano and microstructural features of C-S-H are altered when the calcium-silicate (C/S) ratio is changed (ratios ranging from 0.6 to 1.5) and when the hydration process occurs under different combinations of temperatures and pressures. By testing C-S-H synthesized under varying curing conditions, we will understand the significance of hydration conditions on silicate polymerization and water structure of C-S-H and how C-S-H nanostructure affects its creep, fracture and impact strength. Funds will be used to support graduate and undergraduate students in University of New Mexico (UNM): a minority serving institution. This work will fill a major knowledge gap as most researchers working in the field have focused on the chemical and microstructural nature of C-S-H and very limited research has provided information on the mechanical characteristics of C-S-H. If successful, we will reveal some major mechanical characteristics of C-S-H including creep, fracture and impact strength. Successful research investigation shall lead to necessary changes in cement manufacturing to produce impact-tolerant cement-based composites.