无形三酸盐的热力学稳定性和反应性
Alastair T M Marsh1, Thiago R S Nobre2, Marjorie Etchevers1
1Laboratory of Construction Materials, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland. alastair.marsh@epfl.ch.
概括
无形三酸比其晶体形式更具热力学稳定性. 尽管如此,无形形式的化速度更快,这表明水泥材料的复杂反应动力学.
科学领域:
- 材料科学 材料科学 材料科学
- 化学工程是化学工程的重要组成部分.
- 物理化学 物理化学
背景情况:
- 酸水合物 (C-S-H) 对水泥性能至关重要.
- 了解水合动力学和水泥相的热力学稳定性对于开发先进的建筑材料至关重要.
- 三酸盐 (C3S) 是波特兰水泥的主要成分,显著影响其性能.
研究的目的:
- 与其晶体形式相比,研究无形三酸 (C3S) 的热力学稳定性.
- 分析无形C3S与晶体C3S的水合反应动力学.
- 为了阐明热力学稳定性和C3S水化中的反应速率之间的关系.
主要方法:
- 使用动力模型对C-S-H生长进行分析.
- 使用热量计测量来监测水化反应.
- 比较三酸的无形和晶体形式.
主要成果:
- 无形三酸比其晶体对应物具有更高的热力学稳定性.
- 与晶体C3S相比,水化反应在无形的三酸中开始更快.
- C3S的动力和热力学特性受到其结构状态 (无形与晶体) 的影响.
结论:
- 三酸的无形状态提供了增强的热力学稳定性.
- 尽管稳定性更高,但无形C3S表现出加速的化动力学.
- 这表明无形相可能在早期水化和水泥性能中发挥重要作用.
相关概念视频
Strength and Heat of Hydration
617
The hydration of cement is an exothermic reaction in which heat is generated as cement hydrates. This heat of hydration is critical to cement's strength development. The rate at which this heat is generated affects the temperature rise, with a majority of the heat being released early in the hydration process, half within the first three days, and about 75% within the first week.
The heat of hydration for each cement compound is significant; for instance, tricalcium aluminate (C3A) and...
The heat of hydration for each cement compound is significant; for instance, tricalcium aluminate (C3A) and...
617
Hydration of Cement
757
Hydration of cement is a chemical reaction between cement particles and water. This process occurs primarily through two mechanisms: through-solution and topochemical. In the through-solution process, anhydrous compounds dissolve into their constituents, hydrates form in the solution, and then precipitate from the supersaturated solution. The topochemical process involves solid-state reactions at the cement particle surface. The through-solution process dominates the topochemical process at the...
757
Polymer Classification: Crystallinity
3.7K
Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
3.7K
Ionic Crystal Structures
16.7K
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
16.7K
Sulfate Attack on Concrete
654
Sulfate attack on concrete is a deterioration process characterized by a whitish discoloration beginning at the edges and corners, accompanied by cracking and spalling. This phenomenon occurs when sulfates react with the components of hardened concrete, forming compounds like calcium sulfate and calcium sulfoaluminate which occupy more space than the substances they replace, causing the concrete to expand and disrupt.
Sulfates from sources like soil, groundwater, or industrial effluents...
Sulfates from sources like soil, groundwater, or industrial effluents...
654


