Abstract:
Alkali activated binders (AABs) are a sustainable alternative to Portland cement. They make
use of industrial byproducts rich in aluminosilicates to produce hardened binder which
contain contains hydrous alkali-aluminosilicates under alkaline condition. The local
availability of suitable raw materials (precursors and activators) is a key factor to determine
the utilization of alkali-activated binders in any specific location. This study thus focuses on
using locally available industrial byproducts to make AABs. Rheology and mechanical
properties of Blast furnace slag (BFS)- fly ash binder system activated by sodium hydroxide
and sodium silicate is studied considering different control factors including Na2O/b ratio,
BFS/binder and ⁄ ratio. Na2O/b ratio and ⁄ ratio are optimized
considering the rheology of the alkali activated paste (AAP). The value of BFS/b ratio is then
optimized considering both rheology and mechanical behaviour of AAB system. Alkali activated materials exhibit poor workability in mixing because of high viscosity of the paste
and fast setting. This is great disadvantage considering the placing and transport of the AABs.
In this study, red gypsum and phosphoric acid as additives to enhance the rheological
properties ensuring that the resulting binder have strength comparable to the conventional
cement mortar
