Towards the production of high performance autoclaved binding products from industrial solid wastes

Abstract EN

The object of this investigation is to study the possible production of autoclaved building products using several industrial solid wastes, produced as by-products from certain industries, as pozzolanic materials activated using alkaline activators namely, cement kiln dust (CKD) and hydrated lime [Ca(OH)2].

The ground granulated blast-furnace slag (GGBFS)-cement kiln dust (CKD) mixes were made with and without nano-metakaolin (NMK) and silica fume (SF) as additives.

The four dry mixtures were prepared and subjected to hydrothermal conditions in the autoclave at a pressure of 8 atmospheres of saturated steam for different curing ages of 0.5, 2, 6, 12 and 24 hours.

The autoclaved specimens, thus produced were examined for their chemical and mechanical properties.

These specimens are characterized using thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) as well as compressive strength and kinetics of hydration via the determination of chemically combined water (Wn, % ) and free lime contents at different autoclaved ages.

From the results obtained it was found that the autoclaved products obtained from the autoclaved pastes with addition silica fume (SF) or nano-metakaolin (NMK) possesses improved physico-chemical and mechanical characteristics.

In addition, the extent of enhancement of mechanical properties increases with increasing NMK or SF addition.