TY - JOUR

T1 - Is freeze-drying an alternative to solvent exchange for the hydration stop of cementitious suspensions?

AU - Kißling, Patrick A.

AU - Lübkemann, Franziska

AU - Mundstock, Alexander

AU - Lohaus, Ludger

AU - Haist, Michael

AU - Caro, Jürgen

AU - Bigall, Nadja C.

N1 - Funding Information: The study was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – projects BI 1708/5-1, LO 751/26-1 [77] as well as by the project BI 1708/4-1. In addition, the project leading to these results has in part received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 714429 ). The authors thank A. Feldhoff for access to XRD. The authors thank A. Krabbenhöft (IW) for ESEM measurements. The authors thank Heidelberger Cement AG for providing the cement during the DFG SPP 2005 priority program. The authors thank the Laboratory for Nano- and Quantum Engineering (LNQE) for support.

PY - 2022/9

Y1 - 2022/9

N2 - In order to understand the rheological properties of cementitious suspensions at early stages, among other phases, the formation of ettringite and its time-dependent influence, whether by amount or morphology, has to be examined in detail using a suitable method to stop the hydration process. It is state-of-the-art to exchange water with isopropanol, however, the water initially remains in the system possibly leading to reduced time resolution. Our group raised the question if freeze-drying or the combination of the water-isopropanol exchange with subsequent freeze-drying might be a suitable technique to achieve an almost complete hydration stop at any time. Recently, it was shown under which circumstances low-pressure characterization techniques can be employed without destroying the samples due to loss of crystal bound water. Here, by implementing these recent results, we show under which circumstances freeze-drying indeed can be employed as fast hydration stop method.

AB - In order to understand the rheological properties of cementitious suspensions at early stages, among other phases, the formation of ettringite and its time-dependent influence, whether by amount or morphology, has to be examined in detail using a suitable method to stop the hydration process. It is state-of-the-art to exchange water with isopropanol, however, the water initially remains in the system possibly leading to reduced time resolution. Our group raised the question if freeze-drying or the combination of the water-isopropanol exchange with subsequent freeze-drying might be a suitable technique to achieve an almost complete hydration stop at any time. Recently, it was shown under which circumstances low-pressure characterization techniques can be employed without destroying the samples due to loss of crystal bound water. Here, by implementing these recent results, we show under which circumstances freeze-drying indeed can be employed as fast hydration stop method.

KW - Cementitious suspension

KW - Freeze-drying

KW - Hydration stop

KW - Time-variant analysis

UR - http://www.scopus.com/inward/record.url?scp=85132746995&partnerID=8YFLogxK

U2 - 10.1016/j.cemconres.2022.106841

DO - 10.1016/j.cemconres.2022.106841

M3 - Article

AN - SCOPUS:85132746995

VL - 159

JO - Cement and concrete research

JF - Cement and concrete research

SN - 0008-8846

M1 - 106841

ER -