Effect of precursor and water to binder ratio on water permeability of alkali activated mortars

Thi Nhan Nguyen, Quoc Tri Phung, Lander Frederickx, Diederik Jacques, Alexandre Dauzeres, Jan Elsen, Yiannis Pontikes

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This work investigates the water permeability of alkali-activated materials (AAMs), which is one of the key transport properties beside the diffusivity to assess the material durability. The AAMs were produced from granulate blast furnaces slag (BFS) and metakaolin (MK) with various water/binder ratios of 0.35, 0.45, 0.55, and 0.75, 0.85, 0.95 for BFS and MK based AAMs, respectively. Herein, a direct method using a constant flow controlled by a syringe pump, which has been successfully applied on conventional concrete, was used to measure the permeability of the AAMs. Data was then compared with the OPC mortars with similar w/b ratios. The results reveal that the permeability of BFS activated mortars is comparable to the one of OPC mortars. Both BFS and MK based AMMs are highly sensible with the changes in w/b ratio. The higher the w/b ratio, the higher the permeability. The extent in changing permeability with w/b ratio is stronger for BFS compared to MK based AMMs. Furthermore, a correlation between water permeability and microstructure obtained by nitrogen adsorption of the investigated AAMs is highlighted, which indicates that the permeability of MK based mortars is mostly controlled by capillary pores, while gel pores significantly affect the permeability of BFS based mortars.
Original languageEnglish
Title of host publication4th International Rilem Conference on Microstructure Related Durability of Cementitious Composites · list the conference papers
PublisherTU Delft - Technische Universiteit Delft
Number of pages10
ISBN (Electronic)9789463664226
StatePublished - 29 Apr 2021
Event2021 - 4th International RILEM conference on Microstructure Related Durability of Cementitious Composites : (Microdurability2020) - Online
Duration: 29 Apr 202125 May 2021


Conference2021 - 4th International RILEM conference on Microstructure Related Durability of Cementitious Composites

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