A comparative study of the evaluation methods for pozzolans

Abstract

The range of methodologies available for pozzolan classification, predicated on different viewpoints, may occasionally offer conflicting judgements regarding pozzolans. The present study compared the results obtained by assessing several natural pozzolans, silica fume and fly ash within the requirements of ASTM C618 and ASTM C1240. In addition, binary combinations of the pozzolans and Portland cement were investigated using EN 196-5. The outcomes manifested some anomalies between the different approaches. Complementary observations (such as environmental scanning electron microscope, insoluble residue and hardened concrete properties) were conducted to further clarify the results. The compressive strength and depth of water penetration of the concrete specimens containing the pozzolans revealed that EN 196-5 had superior compatibility with real concrete performance. This suggests that EN 196-5, which was originally developed for pozzolanic cements, can successfully determine the activity of Portland pozzolanic cements containing natural pozzolans, silica fume and fly ash.