The International Centre of Research and Applied Technology for Alkali Aggregate Reactions has confirmed AAR-mitigating potential in ash from April’s Eyjafjallajökull volcano eruption, crediting the material’s particle fineness and approximately 60% silicon dioxide content. Using methods from ASTM C 1260 Multi-Laboratory Study of the Accelerated Mortar Bar Test for Alkali-Silica Reaction, staff at the Mannvit Engineering-housed facility prepared specimens from control (100% portland cement) and ash (5% portland cement substitution) mixes. After the bars’ 14-day exposure in a NaOH solution, Centre founder Børge Johannes Wigum ([email protected]) observed dramatically lower AAR expansion in the ash (0.02%) versus the control (0.45%) specimens.
According to Mannvit Concrete Scientist Karsten Iversen ([email protected]), the ash’s chemical composition is similar to fly ash, adding that she and colleagues also examined grain-size distribution compared to portland cement and fly ash, plus fresh and hardened mortar properties. Test results indicate that the volcanic ash, if feasible to quarry, could have potential as a concrete additive.
— www.manvit.is
