Principal research consultant, Basic Research Section, Chemical/Physical Research Department, Portland Cement Association, Skokie, IL
Although the potential for substantial energy conservation by the use of fly ash in blended cements is well recognized, present test methods and standard specifications do not appear to be adequate to insure predictable performance. A review of the literature led to an analysis of the scientific bases for existing tests for water requirement for pozzolanic activity. Questions are raised concerning the use of fixed proportions in both tests. It is suggested that proportions be adjusted in the mortar flow test to take into account the 45-μm (No. 325) sieve residue of the fly ash. It is also suggested that variable proportions of fly ash and cement be used in the pozzolanic activity tests to facilitate optimization of concrete properties.
Paper ID: CCA10260J