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Sulphate Resistance of Alkali-Activated Material Produced Using Wood Ash
Yiying Du1, Ina Pundiene1, Jolanta Pranckeviciene1
1Laboratory of Concrete Technology, Institute of Building Materials, Vilnius Gediminas Technical University, Linkmenų Str. 28, LT-08217 Vilnius, Lithuania.
Materials (Basel, Switzerland)
|September 27, 2025
Summary
Wood-ash-based alkali-activated materials (AAMs) show reduced durability in sodium sulphate environments due to ettringite formation. However, incorporating specific precursors enhances sulphate resistance, improving material service life.
Area of Science:
- Materials Science
- Civil Engineering
- Geochemistry
Background:
- Sulphate attack significantly impacts construction material durability and service life.
- Alkali-activated materials (AAMs) offer sustainable alternatives but require assessment in aggressive environments.
Purpose of the Study:
- To evaluate the sulphate resistance of wood-ash-based AAMs incorporating various precursors.
- To understand the microstructural and chemical changes in AAMs under sodium sulphate exposure.
Main Methods:
- Compressive strength, mass, and volume changes were measured before and after sodium sulphate cycles.
- Microstructure, elemental composition, and phase identification were analyzed using X-Ray Diffraction (XRD) and scanning electron microscopy (SEM).
Main Results:
- Sulphate exposure caused material degradation (decalcification, dealumination) leading to significant strength loss (60.42%).
- Binary aluminosilicate precursors improved sulphate resistance, reducing strength loss to 18.60% by forming stable hydrates.
- Calcined phosphogypsum addition enhanced sulphate resistance despite initial mechanical property reduction, promoting a compact microstructure.
Conclusions:
- Wood-ash-based AAMs require careful precursor selection for sulphate-rich environments.
- Optimized AAM formulations can achieve enhanced durability and service life in aggressive sulphate conditions.
- The study provides insights into the mechanisms of sulphate attack and mitigation strategies in AAMs.
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