CONCERT_CCair
Component additive approach to predict Cement paste Rheology considering Secondary Cementitious Materials and their special effect on thixotropy and concrete de-airing behaviour
SPP2005 DFG grant SCHA 1854/4-1
Duration: March 2021‒2024
Project leader: Prof. Dr. Thorsten Schäfer
Person in charge: Steffen Hellmann, Frank Heberling, Johannes Lützenkirchen (beide KIT-INE) & Dr. Teba Gil Diaz, Daniel Jara Heredia
Cooperation partner: LUH (Univ.-Prof. Dr.-Ing. Michael Haist) + BUW (Prof. Dr.-Ing. Horst Michael Ludwig)
Project page Concert CCairExternal link
Description:
The collaborative project "Component additive approach to predict Cement paste Rheology considering Secondary Cementitious Materials and their special effect on thixotropy and concrete de-airing behaviour; CONCERT-CCair" within the SPP 2005 is a joint venture between the Bauhaus University Weimar (Prof. Dr.-Ing. Horst-Michael Ludwig), the Leibniz Universität Hannover (LUH; Prof. Dr.-Ing. Michael Haist) and the Friedrich Schiller University Jena (Prof. Dr. habil. Thorsten Schäfer) . Close cooperation within CONCERT and the multi- and interdisciplinary SPP 2005 consortium with researchers from Physics, Chemistry, Materials Science, Civil Engineering and Mineralogy offers unique prerequisites for transferring the findings from basic research into applications.
One of the most essential features of concrete is that it can be shaped in any desired manner by simply pouring and casting. The goal of the casting process in this context is (i) to mold the concrete to the desired shape requiring extensive knowledge on the rheological properties of the concrete and (ii) to remove unwanted air-bubbles from the fresh concrete. Whereas a reasonably clear picture of the mechanisms governing the rheology of cement suspensions made from Ordinary Portland Cement (OPC) starts to emerge, the knowledge of the effect of Secondary Cementitious Materials (SCMs) is still scarce. These materials, however, play an essential role in reducing the CO2 footprint of concrete. The most relevant and promising alternatives for OPC are calcined clays (CCs; see e.g. [1,2]) as well as limestone powders (LSP; see e.g. [3,4] or combinations thereof. The first goal of the current proposal is to extend this approach from pure OPC to CCs and LSPs by studying the influence of hydration of these materials on particle interaction and paste rheology. The two mentioned SCMs are known to strongly influence the thixotropy [5] and thus the de-airing behaviour of concrete, which will be investigated in a second goal of the project. For these topics of study, a series of approaches will be combined involving sample characterization (e.g., XRD, XRF, calorimetry, SEM-EDX, BET, ICP-OES, spICP-MS), the development of surface complexation models (i.e., by means of AFM-measurements and zeta-potentials), and quantification of the rheological properties of hydration products and cement systems (e.g., rheometer, NMR, vibration test systems, etc.).
References:
[1] Scrivener, K.; Martirena, F.; Bishnoi, S.; Maity, S. Calcined clay limestone cements (LC3). In: Cement and Concrete Research vol. 114, (2018), pp. 49–56.
[2] Trümer, A.; Ludwig, H.-M.; Schellhorn, M.; Diedel, R. Effect of a calcined Westerwald bentonite as supplementary cementitious material on the long-term performance of concrete. In: Applied Clay Science vol. 168, (2019), pp. 36–42.
[3] Heberling, F.; Bosbach, D.; Eckhardt, J.; Fischer, U. et al. Reactivity of the calcite–water-interface, from molecular scale processes to geochemical engineering. In: Applied Geochemistry vol. 45, (2014), pp. 158–190.
[4] Voglis, N.; Kakali, G.; Chaniotakis, E.; Tsivilis, S. Portland-limestone cements. Their properties and hydration compared to those of other composite cements. In: Cement and Concrete Composites vol. 27, (2005), No. 2, pp. 191–196.
[5] Nazário Santos, F.; Raquel Gomes de Sousa, S.; José Faria Bombard, A.; Lopes Vieira, S. Rheological study of cement paste with metakaolin and/or limestone filler using Mixture Design of Experiments. In: Construction and Building Materials vol. 143, (2017), pp. 92–103.
[6] Sannac S, Tadjiki S, Moldenhauer E (2013) Single Particle-ICP-MS – an outstanding way to characterize individual nanoparticles. In: Agilent eNewsletter. Available via: https://www.agilent.com/en/newsletters/accessagilent/2013/sep/nanoparticles. Accessed 16 Feb 2021
[7] Laborda F, Bolea E, Jiménez-Lamana J (2014) Single particle inductively coupled plasma mass spectrometry: a powerful tool for nanoanalysis. Anal Chem 86:2270–2278. https://doi.org/10.1021/ac402980q.
