الفهرس 
INTRODUCTION AND OBJECT OF INVESTIGATION
Methods of InvestigationOnly 14 pages are availabe for public view
 |  | from | 106 |  |  |
| | | from | 106 | | |
Abstract
The formation and later accumulation of excessive amounts of different
industrial solid wastes obtained as by-products from certain industries represent a
big pollution problem due its harmful effects on the health of human being in the
surrounding areas of these industries. Therefore, the environmental mitigation and
reduction of the levels of emissions of these pollutants around these industries show
the utmost necessity of utilization and/or prevention of these harmful pollutants.
The object of this investigation is the utilization of the different industrial solid
wastes for the production of certain autoclaved building units having high
performance and reasonable physico-mechanical characteristics as a result of
hydrothermal reactions between pozzolanic materials and alkaline activators.
The alkaline activators used are cement kiln dust (CKD) (the solid waste
produced from cement industries using the ”dry process”) and hydrated lime
[Ca(OH)2]. The pozzolanic materials used in this investigation are ground
granulated blast-furnace slag(GGBFS) (the solid waste produced from big iron
industries), rice husk ash (RHA) (as a source of active silica obtained by burning
of rice husk), nano-metakaolin (NMK) (as an active pozzolanic material obtained
by burning of nano-kaolin followed by activation at 800 ⁰C) and silica fume (SF)
(as a sort of nano-silica obtained from silicon and ferro-silicon industries) where it
condensed from the exhaust gases in the electric arc furnace during reduction of
quartz).
Several dry mixtures were prepared and subjected to steam under 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 were
examined for their mechanical properties (compressive strength test) and the
crushed samples were ground for other physico-chemical studies; where they are
characterized using X-ray diffraction analysis (XRD), thermogravimetric analysis
(TGA) and scanning electron microscopy (SEM) as well as kinetics of hydration
via the determination of chemically combined water (Wn., %) and free lime
contents at different autoclaved ages.