Admixture driven Rheology and Carbonatization pathways of Recycled Concrete Fines (ARCTIC)

该提案涉及到碳化再生混凝土细粉作为未来补充胶凝材料（SCM）的价值。这种新方法结合了许多可持续性方法，即回收、二氧化碳捕获和水泥熟料减少。因此，在碳酸化水泥浆（cCP）领域的研究对于我们发达社会的未来具有重要意义（在德国，建筑垃圾总量约为每年6000万吨）。该领域仍然年轻，许多问题是开放的，例如，关于cCP作为SCM的反应性、水化动力学、机械性能和耐久性。该建议侧重于再生混凝土细粉的碳酸化过程产生的非常大的表面积。这又导致高的水需求，并因此导致低的强度值和不令人满意的耐久性。在这里，我们建议研究策略，以改变所得的表面，无论是化学添加剂或水热后处理。此外，基于聚羧酸酯醚（PCE）的超增塑剂也可以提供显著的减水效果，但迄今为止还没有与碳酸化混凝土细粉组合进行研究。因此，该项目将处理以下专题：a）了解碳酸化产生的大表面积的起源，B）改变的策略c）开发PCE与cCP组合的结构-活性关系，并鉴定用于在含有cCP的水泥体系中减少水的最佳结构作为新型SCM，d）了解新型SCM的反应性，这取决于它们的表面和所使用的PCE化学，以及最后，e）了解新型SCM对水泥水化的影响。

The proposal deals with the valorization of carbonated recycled concrete fines as future supplementary cemenititous material (SCM). This new approach combines many sustainability approaches, namely recycling, capture of carbon dioxide and cement clinker reduction. Hence, research in this field of carbonated cement pastes (cCP) is of great importance for the future of our developed society (construction waste amount to approx 60 million tons per year in Germany). The field is still young and many questions are open, e.g. concerning the reactivity of cCP as SCM, hydration kinetics, mechanical properties and durability. This proposal focuses on the very large surface area which is generated by the carbonation process of recycled concrete fines. This in turn leads to a high water demand and as a consequence to low strength values and unsatisfying durability. Here, we propose to study strategies to change the resulting surface by either chemical additives or hydrothermal post treatment. Additionally, superplasticizers based on polycarboxylate ethers (PCE) also can provide a significant water reduction but have not been studied in combination with carbonated concrete fines as of yet. Consequently, the project will deal with the following topics: a) Understanding the origin of the large surface area generated by carbonation, b) strategies of changing (especially reducing) this surface area, c) developing a structure-activity relationship for PCE in combination with cCP and identifying the best structures for water reduction in cement systems containing cCP as novel SCM, d) understanding the reactivity of the novel SCM depending on their surface and PCE chemistry used and finally, e) understanding the influence of the novel SCMs on cement hydration.