Influence of superplasticizers on the structure-property relationship of fresh cement pastes analyzed by novel rheological combined techniques

采用新型流变组合技术分析高效减水剂对新拌水泥浆体结构-性能关系的影响

• 批准号: 386871659
• 负责人: Professor Dr. Manfred Wilhelm
• 金额: --
• 依托单位: Arbeitsgruppe Polymere Materialien
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/386871659?language=en
• 关键词: Influence; superplasticizers; structure; property; relationship

Our goal is to develop different novel strategies and concepts in order to describe the deformation and flow processes of fresh concrete on the basis of molecular processes, taking also into account mesoscopic processes. One important point is the analysis and penetration of the relevant processing operation of fresh concrete using rheology as the main technique and combined it in-situ with complementary methods (dielectric, NMR, SAXS and IR) offering molecular or structural information. Rheology is highly influenced by the morphology and the molecular properties of the investigated materials, e.g. fresh concrete. Rheology can establish the result of the interplay between molecular structure and mechanical properties, the combination of rheology with complementary methods allows to gain unique information about molecular dynamic, structure of time and shear dependent phenomena.Rheo-dielectric: the combination of rheological and dielectric properties can give detailed information about the relation between local molecular relaxation dynamics e.g. water and the macroscopic response to mechanical forces. In mortar or concrete, the cement paste is submitted to different shear stresses during processing and settling, e.g. the pouring of the material into a mould or framework. Therefore, rheological measurements will be carried at different rates for different durations.Rheo-NMR: Providing adequate moisture content in cement-based materials is important during hydration of the cement paste to ensure proper development of their mechanical and durability properties. Water is involved in the formation and deterioration of concrete either as a pure liquid or by carrying aggressive species. 1H-NMR relaxation time studies of hydrating cement based materials combined with rheology can be used to study simultaneously the molecular dynamics via NMR and the corresponding mechanical response for fresh concrete mixtures.Rheo-IR: This method will be implemented during the proposed project to study the chemistry of cement hydration. In the proposed project the hydration of fresh cement samples will be monitored by means of infrared spectroscopy. The mechanisms of the interaction between individual particles or between particles and the carrier liquid will be investigated with Rheo-IR technique for a better understanding of the rheological behavior of fresh building material suspension. To accomplish first this, we need to develop a new setup that is able to simultaneously measure rheological and infrared spectra with an improved sensitivity to directly correlate mechanical nonlinearity with IR spectroscopy. The new and worldwide unique combined methods will enable the investigation and analysis of the interaction of reactive (hydrating) particles, including the ability to quantify the effects of morphology, chemistry, temperature, time, etc. leading to a more complete model of particle interactions in fresh concrete materials.

我们的目标是制定不同的新型策略和概念，以根据分子过程来描述新鲜混凝土的变形和流动过程，并考虑到介观过程。一个重要的一点是，使用流变学作为主要技术的新鲜混凝土的相关加工操作进行分析和渗透，并将其与提供分子或结构信息的互补方法（介电，NMR，SAXS和IR）相结合。流变学受到所研究材料的形态和分子特性的高度影响，例如新鲜混凝土。流变学可以建立分子结构与机械性能之间相互作用的结果，流变学与互补方法的组合可以获得有关分子动态，时间和剪切依赖现象的独特信息。RHEO-DIELECTRIC：RHEOLE-DIELECTRIC：流变学和介电特性的组合可以提供有关局部局部遗物的详细信息。有关局部相关性的信息。水和对机械力的宏观反应。在砂浆或混凝土中，水泥糊剂在加工和沉降过程中以不同的剪切应力提交，例如将材料倒入模具或框架中。因此，在不同的持续时间内将以不同的速率进行流变学测量。RHEO-NMR：在水泥糊的水合过程中，在基于水泥的材料中提供足够的水分含量很重要，以确保其机械和耐用性的适当发展。水与混凝土形成和恶化是纯液体或携带侵略性物种。与流变学结合的水合水泥材料的1H-NMR松弛时间研究可用于通过NMR同时研究分子动力学，以及对新鲜混凝土混合物的相应机械响应。RHEO-IR：将在建议的项目中实现此方法，以研究水泥化学的化学水平。在拟议的项目中，将通过红外光谱法监测新鲜水泥样品的水合。将使用Rheo-IR技术研究单个颗粒之间或颗粒与载体液体之间相互作用的机制，以更好地理解新鲜建筑物材料悬架的流变行为。首先，我们需要开发一种能够同时测量流变学和红外光谱的新设置，并具有提高灵敏度直接将机械非线性与IR光谱相关的灵敏度。新的和全球独特的组合方法将使反应性（保湿）颗粒相互作用进行研究和分析，包括量化形态，化学，化学，温度，时间等效果的能力。导致新鲜混凝土材料中粒子相互作用的更完整模型。