Microstructure as a key parameter for understanding chloride ingress in alkali-activated mortars

Scientific paper - Original scientific paper

• Author: Antonino Runci
• Author: John Provis
• Author: Marijana Serdar
• Author's institution: University of Zagreb; Faculty of Civil Engineering
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Civil Engineering

Abstract (english)

This study aims to evaluate the influence of microstructural properties on the chloride diffusion resistance of alkali-activated materials (AAMs) based on blast furnace slag and/or fly ash, with variable activator doses (represented as Na2O%). Resistance to chloride penetration was tested using accelerated chloride penetration (NT BUILD 443) and chloride migration (NT BUILD 492) tests. Addition of slag to alkali-activated mortars mainly based on fly ash reduced porosity and chloride permeability. Chloride penetration decreased with increasing Na2O%, but porosity and pore structure did not follow the same trend. The pore threshold (dth) and critical pore radius (rcrit) determined by mercury intrusion porosimetry had a good correlation with the chloride diffusion coefficient. Both the quantification of reaction products and the correlation between chloride penetration and pore surface area indicated that physical chloride adsorption on the C-A-S-H/N-A-S-H gel surfaces predominated over chemical chloride binding.

• Keywords (english): Alkali-activated materials; Chloride diffusion; Chloride migration; Microstructure; Porosity; Chloride binding capacity
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Cement & concrete composites
• Numbering: vol. 134, 104818
• e-ISSN: 1873-393X
• URN:NBN: urn:nbn:hr:237:782443
• Publication: 2022
• Type of resource: Text
• Access conditions: Open access
• Created on: 2024-09-04 20:00:16