Impact of alkalis and shrinkage-reducing admixtures on hydration and pore structure of hardened cement pastes - Archive ouverte HAL
Article Dans Une Revue Cement and Concrete Research Année : 2024

Impact of alkalis and shrinkage-reducing admixtures on hydration and pore structure of hardened cement pastes

Ippei Maruyama
Matthieu Vandamme
Jean-Michel Pereira

Résumé

The hydration and pore structure of hardened cement pastes containing various amounts of alkali and hexylene glycol -a shrinkage-reducing admixture (SRA)- are studied. Until three months, SRA retards cement paste hydration regardless of alkali content; after seven days at most, this retardation diminishes with time. Alkalis increase the hydration degree at early ages for all pastes. The pore structure coarsens with the SRA: both the specific surface area and the volume of pores with a 5 nm entry size decrease in the presence of the SRA. The magnitude by which the SRA impacts the pore structure reduces with alkali. In alkali media, the C-S-H gel uptakes alkalis and aluminum; modifying the C-S-H structure, the gel pore volume, and the interlayer space. The SRA depletes the alkalis from the solution and may increase the C-S-H alkali uptake, which could lead to changes in the gel pore volume and specific surface area.
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dimanche 26 janvier 2025
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Dates et versions

hal-04662681 , version 1 (26-07-2024)

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Hafsa Rahoui, Ippei Maruyama, Matthieu Vandamme, Jean-Michel Pereira, Martin Mosquet. Impact of alkalis and shrinkage-reducing admixtures on hydration and pore structure of hardened cement pastes. Cement and Concrete Research, 2024, 184, pp.107620. ⟨10.1016/j.cemconres.2024.107620⟩. ⟨hal-04662681⟩
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