LOWERING FOAM INDEX IN HIGH-CARBON FLY ASHES FOR CONCRETE APPLICATIONS

摘要

These experiments indicate that both unburned carbon and soluble ions such as calcium and magnesium can have an impact on FI. Their relative effects are most likely dependent on the properties of the carbon and mineral components of the fly ash and not their relative proportions in the ash. Thermal treatment of the fly ashes under oxidative conditions clearly has an impact on FI. Conductance measurements of fly ash thermally treated under inert conditions does suggest a decrease in the solubility of ions which are known to interfere with the fatty acids surfactant in the FI test, thus lowering the FI values.