STUDIES ON THE EFFECT OF THE COPPER AND ZINC CONTENT IN A SILICA BY-PRODUCT MATERIAL WHEN USED IN MORTAR

Mortars were prepared with an industrial incinerator waste material si milar to silica fume as an additive to or a partial replacement for ce ment to investigate whether the copper and zinc contents present in th e waste material had an adverse effect on the compressive strength. Wh en used as a cement replacement, high copper contents (0.69, 0.96, 1.3 8% by weight of pozzolanic material ) were detrimental to the early st rength development. Lower copper contents (0.24 and 0.48% by weight of pozzolanic material) did not affect the strength development. When us ed as an additive to cement in mortar, the copper content of the mater ial did not affect the strength development . Higher compressive stren gth compared to a control resulted when the material was used as a 10, 15, or 20% additive to cement (based on the percent weight of cement) . Conclusions regarding the effect of the zinc content could not be dr awn due to the significant copper concentration relative to the concen tration of zinc in the waste material.