Influence of metahalloysite on mitigating alkali-aggregate reaction in concrete
Year: 2025
Type: article
Abstract: The durability of concrete structures can be compromised by alkali-aggregate reaction, a chemical process between the alkalis and reactive minerals within the aggregate. The reaction produces a gel of hydrated sodium-potassium-calcium silicate that expands in the concrete, deteriorating it. Adding mineral admixtures to concrete is recognized as a highly effective strategy to mitigate expansion due to alkaliaggregate reactions. This study investigated the use of a natural mineral admixture, metahalloysite, to mitigate the reaction effects. Expansion tests were conducted according to ASTM C441. The microstructure of the expanded specimens was examined using computed tomography and scanning electron microscopy coupled with X-ray microanalysis. The results showed that the 25% cement substitution with metahalloysite significantly lowered the swelling of the concrete specimens, keeping it within safe limits. Microstructural examination of the specimens without admixture showed numerous cracks in the aggregate grains, the presence of reaction products, and ettringite crystals. Specimens with admixture showed the presence of non-swelling sodium-potassium silicate gel and a dense C–S–H phase with a reduced C/S ratio.
Source: Archives of Civil Engineering
Authors: Zdzisława Owsiak, Anna Leks
Institution: Kielce University of Technology
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $652
OpenAlex ID: W4414415509
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