The Influence of Activator Composition on the Strength, Shrinkage and Chloride Migration Resistance of Alkali-Activated Slag Mortars

Abstract:

Alkali-activated slag materials are known for their high chloride penetration resistance. This makes them potentially applicable as repair systems for damaged steel-reinforced concrete structures, which are exposed to chloride attack. For this purpose, the influence of the activator composition, i.e. the SiO₂ and Na₂O concentration of the alkaline solution on a) the compressive strength, b) shrinkage and mass change and c) the resistance against chloride penetration of four alkali-activated slag mortars (AASM) were studied. An ordinary Portland cement-based mortar was used as the reference sample. Increasing SiO₂ and Na₂O concentrations increased the strength, shrinkage and mass loss of the AASMs. The resistance of the mortars against chloride penetration was evaluated using the non-steady-state migration coefficient D_nssm obtained from NT BUILD 492. The results indicate that the D_nssm is related to differences in the pore solution of the AASMs rather than to differences in their microstructure. An upcoming study of the authors is going to evaluate this hypothesis by the accelerated chloride penetration (diffusion) test.

• Periodical: Key Engineering Materials (Volume 761)
• Pages: 61-64
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.761.61
• Online since: January 2018
• Authors: Nan Jie Hu*, Götz Hüsken, Gregor J.G. Gluth, Hans Carsten Kühne
• Keywords: Alkali-Activated Slag Mortar, Chloride Migration Coefficient, Shrinkage, Strength

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