Skip to Main content Skip to Navigation
Journal articles

Supercritical drying of cementitious materials

Abstract : Techniques to characterize the microstructure of hydrated cement require dried materials. However, the microstructure of hydrated products is significantly altered by high capillary forces during drying when using the conventional drying methods. To avoid drying stresses when preparing samples, we have employed supercritical drying (SCD) which has been used for decades to prepare aerogels that undergo no shrinkage during drying, but has rarely been used for cementitious materials. The pore solution is first replaced with isopropanol, and then with trifluoromethane (R23). The temperature and pressure are raised above the critical point, where no menisci or capillary pressure can exist; therefore, the dried samples are free of artifacts created by stresses. Images from scanning electron microscope show less compact morphology for supercritically dried samples than that dried by conventional methods, while BET surface areas of SCD samples are very close to samples dried by isopropanol replacement method. This can be explained by the fact that isopropanol and supercritical fluid enter the micropores and block them. The nature of the chemical interactions of isopropanol and R23 with cement pastes are still not clear, but no reaction products were identified in the present study.
Document type :
Journal articles
Complete list of metadata

Cited literature [70 references]  Display  Hide  Download

https://hal-enpc.archives-ouvertes.fr/hal-01622913
Contributor : Zhidong Zhang Connect in order to contact the contributor
Submitted on : Tuesday, October 24, 2017 - 6:03:40 PM
Last modification on : Wednesday, October 31, 2018 - 11:20:04 AM
Long-term archiving on: : Thursday, January 25, 2018 - 3:05:43 PM

File

CCR2017_SCD_experiment.pdf
Files produced by the author(s)

Identifiers

Collections

Citation

Zhidong Zhang, George Scherer. Supercritical drying of cementitious materials. Cement and Concrete Research, Elsevier, 2017, 99, pp.137-154. ⟨10.1016/j.cemconres.2017.05.005⟩. ⟨hal-01622913⟩

Share

Metrics

Les métriques sont temporairement indisponibles