Acceleration of cement hydration with synthetic calcium silicate hydrates II - Mechanism of action and significance for alternative binders

合成水合硅酸钙加速水泥水化 II - 替代粘合剂的作用机制和意义

• 批准号: 314734048
• 负责人: Professor Dr. Dietmar Stephan
• 金额: --
• 依托单位: Fachgebiet Baustoffe und Bauchemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/314734048?language=en
• 关键词: Acceleration; cement; hydration; synthetic; calcium

Portland cement-based binders are currently the most used synthetic material on earth. As a result, the cement industry is responsible for about 8% of the anthropogenic CO2 emissions. Moreover, the industry is growing. A reduction of the clinker share in composite cements results in a slower reaction kinetics which must be compensated by effective accelerators. The project "Acceleration of cement hydration with synthetic calcium silicate hydrates II - mechanism and implications for alternative binders" aims to adapt the promising concept of C-S-H seeding to other SCMs and binders. In a first step, a deeper understanding of the mechanism shall be obtained. The acceleration of cement hydration by artificial C-S-H is commonly attributed to the nucleation of hydration products on the extra surface. However, clear evidence for this assumption is missing. Moreover, additional information about seed and product interaction is needed for a tailored synthesis of individual seeding materials. This first goal shall be achieved indirectly by investigating the interaction of well-characterized concrete additives with C-S-H seeds in cement. Moreover, the direct interaction of seed and binder shall be investigated by separating the reaction environment and in-situ methods. In-situ infrared studies conducted in the previous project proved to be very promising and provided valuable information on the reaction process during C-S-H synthesis. The method is now to be adapted to the entire binder system as part of the proposed project. The work is supplemented by modelling the hydration process. Based on the results, targeted modifications of the C-S-H seed will be investigated to reveal the full potential of the method. To this end, an inorganic approach will be pursued in which crystalline C-S-H phases are produced, or foreign atoms are incorporated into the structure of the amorphous C-S-H. On the one hand, organic composites are to be produced with concrete admixtures to obtain multifunctional additives; on the other hand, the interaction with polymers, whose influence on the morphology of minerals is known, is to be investigated. The results from the first two work packages will be combined to achieve the last objective - adapting the method to alternative binders. Initially, binders whose reaction product is calcium silicate hydrate, as in Portland cement, will be analyzed. Finally, binders with different hydration products such as calcium aluminate cement shall be activated by tailored nucleation seeds.

波特兰水泥基粘结剂是目前地球上使用最多的合成材料。因此，水泥行业占人为二氧化碳排放量的8%左右。此外，该行业正在增长。复合水泥中熟料份额的减少导致反应动力学变慢，这必须通过有效的促凝剂来补偿。“用合成硅酸钙水合物加速水泥水化II ----替代粘结剂的机理和意义”项目旨在使C-S-H引晶的前景概念适用于其他SCM和粘结剂。第一步，应更深入地了解该机制。人工C-S-H对水泥水化的加速作用通常归因于水化产物在水泥表面的成核作用。然而，这一假设缺乏明确的证据。此外，需要关于种子和产品相互作用的额外信息来定制合成单独的种子材料。这第一个目标应通过研究良好表征的混凝土添加剂与水泥中C-S-H种子的相互作用间接实现。此外，种子和粘结剂的直接相互作用应通过分离反应环境和原位方法来研究。在上一个项目中进行的原位红外研究被证明是非常有前途的，并提供了有价值的信息的反应过程中C-S-H合成。作为拟议项目的一部分，该方法现在将适用于整个粘结剂系统。这项工作的补充是模拟水合过程。基于结果，将研究C-S-H种子的靶向修饰，以揭示该方法的全部潜力。为此，将采用无机方法，其中产生结晶C-S-H相，或将外来原子并入无定形C-S-H的结构中。一方面，有机复合材料将与混凝土外加剂一起生产，以获得多功能添加剂;另一方面，将研究与聚合物的相互作用，其对矿物形态的影响是已知的。前两个工作包的结果将结合起来，以实现最后一个目标-使方法适应替代粘合剂。首先，将分析反应产物为水合硅酸钙的粘合剂，如波特兰水泥。最后，具有不同水化产物的粘合剂，如铝酸钙水泥，应通过定制的成核种子进行活化。