The composition and pozzolanic properties of pulverised fuel ashes

The pozzolanic activities of the fly ashes and other materials examined in previous papers1,2 have been determined by two chemical methods based on estimating the amount of acid-soluble material that is produced when a pozzolan reacts with lime. The conclusions reached from these results, on the relative importance of the factors that determine the activity of an ash, agree with those previously based on the crushing strengths of fly ash mortars, as already presented. There was a close relation between the amount of chemical reaction taking place in a mortar and the strength it developed, but short-term chemical assessments showed no relation to long-term crushing strengths. It was concluded that chemical methods were unlikely to have any practical value for predicting the long-term strength of a mortar in the field.