Estimation of pozzolana content in Portland pozzolana cement

A simple and rapid method based on cold and dilute hydrochloric acid has been developed to determine pozzolana content in Portland pozzolana cements (PPC). The method is applicable to different types of pozzolana even in the absence of original samples of ingredients used in the production of PPC. A 5% (v/v) solution of HCl (sp. gr. 1.18) cooled below 10°C is used to digest the cement sample and separate out pozzolana content. The estimation is completed in about 4 hours time. The results obtained by this method for different PPCs made from different samples of fly ash, calcined clay and rice-husk clay pozzolana were fairly accurate (within ± 7.5% error) and were better than those obtained by picric acid method and even modified picric acid method.