On the structure and the formation of the structure of C-S-H phases in future cementitious binders

混凝土是我们这个时代的主要建筑材料。在全球范围内，水泥是混凝土中最重要的粘结剂。但水泥的制造与二氧化碳的强烈排放有关。为了减少这些排放，目前全世界都在制定替代方案。从中期来看，一个很好的选择是用复合材料(SCM)部分取代波特兰水泥熟料。波特兰(复合)水泥与水的反应导致纳米级硅酸钙水合物(C-S-H)相的形成--硬化混凝土中的主要水化相。这些阶段决定了混凝土的大部分宏观性能。C-S-H的结构和结构形成目前还不够清楚，是建议的主要主题。必须了解成功应用新水泥的参数，并为这些粘结剂的新应用铺平道路。在两位申请者的合作基础上，有关结构形成的新方法将从基础科学转移到工程学。这一点甚至更重要，因为已经发现晶体的形成不仅限于单体-单体的结合。此外，前驱物相的聚集也是一种潜在的结晶(非经典结晶)途径。这为混凝土宏观性能的设计开辟了新的视角。在第一部分(实际体系)中，研究了不同超临界胶凝材料水泥中C-S-H相的形成条件。在第二部分中，用纯方法(模型系统)合成了这些相。在第三部分中，主要用分析超速离心法和动态光散射法研究了通过潜在前驱物相形成的结构和外加离子的影响。在这里，如果胶凝体系中确实存在潜在的前驱体相，则具有中心意义，因此是非经典结晶理论的进一步迹象。在第四部分中，主要研究了C-S-H相的结构(晶格、溶解度)，特别关注了SCM引入的外来离子(浓度和种类)的影响。在这里，必须满足对合成和方法的高要求。因此，光谱学、电子显微镜以及同步辐射的衍射将相辅相成。最后对集料与水泥石的界面过渡区进行了研究。在这里，我们期望搭建一座从基础科学到具体科学的桥梁。该项目的结果将进行跨学科讨论，并在适当的期刊上发表。进一步了解水泥这一最重要的反应产物的结构和结构的形成是该提案的主要目的。

Concrete is the main building material in our time. At a global level, cement is the most important binder within the concrete. But the manufacture of cement is associated with a strong emission of CO2. In order to reduce these emissions, alternatives are currently worked out worldwide. In a medium-term, a good alternative is to partly substitute Portland cement clinker by composite materials (SCMs). The reaction of Portland(composite) cements with water leads to the formation of nanoscaled Calcium-Silicate-Hydrate (C-S-H) phases -the main hydrate phases in hardened concrete. These phases are responsible for most of all macroscopic properties of concrete. Both structure and formation of structure of C-S-H are currently not sufficiently known, and are the main subjects of the proposal. It is essential to know both parameters for the successful application of the new cements and also to pave the way for these binders for new applications. New approaches regarding structure formation will be transferred from the fundamental science to engineering based on the collaboration of the two applicants. This is even more important, since it is found that crystal formation is not restricted only to monomer-monomer attachment. Also the aggregation of precursor phases is a potential route for crystallization (non-classical crystallization). This opens new perspectives in the design of the macroscopic properties of concrete.The proposal is systematically subdivided into five parts. The conditions of formation of C-S-H phases is investigated within cements with different SCMs during the first part (real system). In the second part, these phases are synthesized in a pure way (model system). Within the third part, the formation of the structure via potential precursor phases and the impact of foreign ions is mainly investigated by means of Analytical Ultracentrifugation and Dynamic Light Scattering. Here it is of central relevance if potential precursor phases do exist in cementitious systems, and thus are further indications for the non-classical crystallization theory. In the fourth part, the investigation of the structure (crystal lattice, solubility) of these C-S-H phases is mainly focused with special attention on the impact of the foreign ions introduced by SCMs (concentration and kind). Here high requirements have to meet regarding synthesis and methods. Thus, spectroscopy, electron microscopy as well as diffraction with synchrotron radiation will complementary be performed. The interfacial transition zone between aggregates and cement stone is investigated in the last part. Here we anticipate to build a bridge from fundamental science to concrete. The results of the project will be interdisciplinary discussed and published in appropriate journals. To get a step forward in understanding the structure and the formation of the structure of the most important reaction product of cement is the main aim of the proposal.