Interaction between cement and cellulose ether

对未来水泥建筑材料的主要需求之一是大幅减少二氧化碳足迹。开发新的、更可持续的水泥是一个持续的过程，将导致各种各样的可用性。建立关于这些可持续水泥与混凝土和砂浆生产中使用的外加剂相互作用的基本知识是一个重大挑战，需要解决这个问题，以使可持续水泥进入更广泛的应用领域。因此，该项目旨在研究羟基乙基甲基纤维素（HEMC）与基于可持续水泥的砂浆的相互作用。这将为可持续水泥在干砂浆行业的应用铺平道路。所研究的水泥被选中代表可能的砂浆生产在不久的将来在中国和欧洲。该提案的新方法不仅是将中国和德国的研究更紧密地联系在一起，而且还拓宽了现有的分析方法，带来了根本性的新见解。工作包包括仔细表征和选择原材料（WP1），研究HEMC与各个胶凝相的基本相互作用（WP2），以及监测含有HEMC的可持续砂浆的性能。由于HEMC应用于干砂浆以增加保水性，因此研究的一个主要方面集中在水的流动性表征上。因此，质子核磁共振弛豫测量将在同济大学工作组（WP2）中建立。将在Bauhaus-Universität上开发计算机断层扫描在3D水平上表征干砂浆孔隙度的补充应用。HEMC的另一个副作用是阻碍水合作用。通过研究各个水泥组分（阿利特、铝酸盐、scm -阿利特混合物）与HEMC的相互作用，并将其分解为溶解和沉淀过程（WP2），我们将对缓凝机理有一个基本的了解。对含有可持续水泥和HEMC的砂浆性能进行表征将记录其性能并实施适当的测试方法（WP3）。该方法将在完善基础知识的基础上，促进HEMC在干砂浆中的安全应用。

One of the major demands on future cementitious building materials is a dramatically reduced CO2 footprint.Development of new, more sustainable cements is an ongoing process that will lead to a broad variety of availablecements. Establishing basic knowledge on the interaction of these sustainable cements with admixtures used inconcrete and mortar production is a major challenge, which needs to be solved to bring sustainable cements into awider field of application. Thus, the proposed project aims to investigate the interaction of Hydroxy Ethyl MethylCellulose (HEMC) with mortars based on sustainable cements. This will pave the way to an increased applicationof sustainable cements in the dry mortar industry. The investigated cements are selected to represent possiblecandidates for mortar production in the near future in China and in Europe.The new approach of the proposal is not only to bring Chinese and German research closer together, but alsoto widen the available analytical methods to bring fundamental new insights. Work packages include carefulcharacterization and selection of raw materials (WP1), study of the basic interaction of HEMC with individualcementitious phases (WP2), and monitoring of the properties of sustainable mortars containing HEMC.Since HEMC are applied to dry mortars to increase water retention, one main aspect of the investigationfocuses on the characterization of the mobility of water. Therefore, proton NMR relaxometry will be establishedin the working group at Tongji University (WP2). Complementary application of computed tomography tocharacterize the porosity of dry mortars at a 3D level will be developed at the Bauhaus-Universität. Another sideeffect of HEMC is the retardation of hydration. A basic understanding of the mechanism of retardation will begained by investigations on the interaction of individual cement components (alite, aluminate, SCM-alite blendsetc.) with HEMC and by separating into dissolution and precipitation processes (WP2). Characterization of mortarproperties containing sustainable cements and HEMC will document performance and implement proper testmethods (WP3). This approach will lead to the safe application of HEMC in dry mortars based on sound basicknowledge.