Volcanic ash and pumice as cement additives: pozzolanic, alkali-silica reaction and autoclave expansion characteristics

This study reports the results of investigation to assess the suitability of volcanic ash (VA) and pumice (VP) powder to be used as cement additives. Pozzolanic activity of VA and VP was tested according to the Italian standard and found to be acceptable. The strength activity index with Portland cement and the effectiveness of VA and VP admixture in controlling alkali-silica reaction and autoclave expansion were tested according to ASTM standards. Mortar cubes were specially prepared as per ASTM standards for these studies using different mixes with varying percentages of VA and VP (0-40%) as cement replacement. The results are then compared with ASTM requirements to assess the suitability of VA or VP as cement additives.