The suitability of replacing Portland cement by an as received dealuminated
calcined kaolin waste obtained from an alum production factory through the extraction
of aluminum, also by dealuminated samples treated with lime solution, is investigated.
The chemical and mineralogical compositions of the samples are measured. Their
pozzolanic reactivity and their surface areas were determined. The effect of
replacement on the setting time, the flowability, rate of flowability loss and strength of
mortars was tested and compared to control OPC samples and others containing silica
fumes.
It was found that the as received dealuminated kaolin and that treated with lime
possess higher pozzolanic reactivity and show larger surface areas than silica fumes.
The incorporation of the as received dealuminated kaolin in OPC paste accelerates the
setting time; while the lime-treated samples lead to retardation. The flowability of the
OPC mortar is little affected by the as received DK samples and is strongly reduced by
the lime-treated one and silica fumes. The three admixtures cause strong flowability
loss with time. The 56d-compressive and |
