Extraction and analysis of pore solution of cement paste: desaturation and resaturation cycles using a non-destructive method by gas injection

Abstract

The aim of the present study is to extract the pore solution from cement pastes and mortars with high W/C ratio by a non-destructive method. The sample is placed in a hydrostatic cell under a confining pressure and an inert gas under high pressure is applied at one end to force a movement of interstitial water. As a result of the non-destructive nature of this method, successive extractions were carried out on cement pastes with W/C ratio equal to 0.7: the first one is directly performed on three initially saturated samples and the second one after drainage and resaturation by two chemically different solutions to observe the exchanges between the saturating solution and cementitious matrix. The chemical analysis results of K⁺, Na⁺, SO₄²⁻, Mg²⁺, Ca²⁺, Li⁺ and Sr²⁺ show that the volume of extracted water is representative of concentrations of the various ionic species present in a pore solution of cement pastes.

Keywords:

• Cement pastes
• pore solution
• extraction method
• non-destructive method
• chemical analysis
• curing condition

Notes

1. Interstitial extracted solutions were diluted with osmosis water, and the concentrations present in Table 3 correspond to the concentrations calculated taking into account the volume extracted from each extraction.