Medhat S. El-Mahllawy
Housing and Building National Research Center
Egypt
Title: Effect of activation of granulated blast- furnace slag on the properties of unfired eco-friendly clay bricks
Biography
Biography: Medhat S. El-Mahllawy
Abstract
This laboratory study was undertaken to evaluate the properties of eco-friendly clay specimens incorporating ground granulated blast-furnace steel slag (GGBS) which activated by cement kiln dust (CKD) and quicklime (QL) of various dosages (5-10wt.%). The use of activated GGBS in the manufacture of unfired clay bricks is, however, still a novel process in Egypt although it has been used previously in some countries. Five mixes were prepared and laboratory specimens were made and cured up to 60 days. X-ray diffraction (XRD) and differential thermal analysis (DTA) were used to characterize the raw materials and specimens. In addition, physical and mechanical properties of the hydrated specimens were measured and their results were illustrated graphically. Also, durability of the cured specimens against collapsibility in water was assessed. The addition of quicklime and cement kiln dust to the GGBS improved the investigated engineering properties of the unfired stabilized specimens. This is due to the pozzolanic reaction that results in the accumulation of additional calcium silicate hydrates (CSH) and calcium aluminate hydrates (CAH) gel within the pore structure. This resulted in the enhancement of the properties in the investigated mixes after 7 days of curing, particularly 14 days, with superiority to the clay-cement-lime-GGBS mix rather than the clay-cement – CKD- GGBS mix. In general, the specimens contained GGBS activated by 5wt.% quicklime had the most potential effect on the studied properties.