Influence of variability of oil shale fly ash on compressive strength of cementless building compounds

The variability of fractional, chemical and mineralogical compositions of Israeli oil shale fly ash (OSFA) were examined. The effect of CaOfree content in OSFA and the age of the test specimens, prepared on the basis of daily and monthly OSFA samples, on their compressive strength as well as contribution of interaction of these factors in strength were estimated by the regression analysis and Analysis of Variances (ANOVA). The influence of exposure time of OSFA to ambient air on compressive strength was also assessed. Finally conclusions concerning the OSFA variability and compressive strength of concrete like building compounds were made.