Interaction between cement and cellulose ether

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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.