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Durable Mortar Mixes Using 50% of Activated Volcanic Ash as A Binder
Andrés Játiva1, Andreu Corominas2, Miren Etxeberria1
1Department of Civil and Environmental Engineering, Polytechnic University of Catalonia, Jordi Girona 1-3, B1-104A, 08034 Barcelona, Spain.
Materials (Basel, Switzerland)
|May 7, 2025
Summary
Volcanic ash (VA) can replace Portland cement in mortars when its reactivity is enhanced. Calcination, alkali activation, and specific curing methods significantly boost mortar strength and durability.
Area of Science:
- Materials Science
- Civil Engineering
- Geochemistry
Background:
- Volcanic ash (VA) is a widely available pozzolanic material.
- Low reactivity of VA limits its use as a supplementary cementitious material (SCM).
- Enhancing VA reactivity is crucial for its broader application in cement replacement.
Purpose of the Study:
- To evaluate methods for improving the reactivity of volcanic ash.
- To assess the impact of activation and curing on mortar properties.
- To optimize volcanic ash-based mortar performance.
Main Methods:
- Calcination of volcanic ash (CVA) at 700 °C.
- Alkali activation using sodium silicate (Na2SiO3), calcium chloride (CaCl2), and sodium carbonate (Na2CO3).
- Combination with other SCMs (lime, fly ash, blast-furnace slag) and evaluation under moist and heat curing regimes.
Main Results:
- Alkali activation (2% Na2SiO3, 1% CaCl2) and heat curing (70 °C for 3 days) significantly increased 28-day compressive strength in 50% VA mortars.
- Addition of fly ash (10%) and slag (5%) further enhanced strength.
- Heat-cured mortars showed reduced shrinkage, lower water absorption, and improved acid resistance, especially with CVA and CaCl2.
Conclusions:
- Optimized activation and curing methods enable effective use of 50% volcanic ash as a cement replacement.
- These strategies enhance early-age strength, reduce shrinkage and water absorption.
- Improved acid resistance is achieved, making VA-based mortars suitable for demanding applications.
Keywords:
alkali-activatedcalcinationcementhigh-volume volcanic ashmortarsupplementary cementitous materialthermal curingMore Related Videos
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