OPTIMIZATION OF ALKALI ACTIVATION OF GROUND GRANULATED SLAG WITH MINING TAILS

Pablo Santizo Matheu, Ashley Waldron, Benjamin Varela

Abstract: Previous studies have shown that the reinforcement of alkali activated ground granulated blast furnace slag (GGBFS) with Wollastonite micro-fibers enhances the compressive strength and thermal stability of the composite. Compressive strength of alkali activated slag with 10% of Wollastonite per mass reached a 7 day compressive strength of 55.15 MPa (8000 psi). However, the estimated cost of this formulation is six times greater than similar concretes based on ordinary Portland cement. Different aggregates were tested to reduce the cost of this formulation. It was found that when mine tailings were added, the 7 day compressive strength reached 41.36 MPa( 6000 psi)), the setting time doubled and the cost was reduced by 2/3. These results are promising for the development of a cost effective formulation. Based on these results, a two factorial design with a three level design of experiments was conducted to explore the joint effect of Wollastonite and mine tailings on alkali activated GGBFS. In order to find the significant factors, the compressive strength would act as the response variable. The setting time and cost of each combination is also considered to find the optimal combination resulting from the experiment.

Keywords: Wollastonite micro-fibers, ground granulated blast furnace slag, alkali-activation, reinforcement, mine tailings

DOI: https://doi.org/10.15623/ijret.2014.0325017