Experimental study on effect of replacing pumice and fly ash on the durability of alkali-activated slag concrete

Portland cement production, using a lot of resources and energy, emits a significant amount of carbon dioxide, which can be a worrying factor for the environment. Alkali-activated materials prepared with aluminosilicates and alkaline activators are among the eco-friendly alternatives of Portland cement in concrete production and have been extensively studied in the last few decades because of their environmentally friendly nature and high resistance against harmful exposures. In this research, alkali-activated slag-based concrete has been made by replacing slag with 15% and 30% by fly ash and 10% and 20% by pumice powder. Tests of compressive strength, splitting tensile strength, water absorption and accelerated corrosion of rebar were considered for evaluating effect of replacements on mechanical properties and durability of concrete. The results show that the replacement of slag with different amounts of pumice and fly ash leads to the weakening of the mechanical characteristics, the increase of permeability and water absorption, as well as the reduction of the potential of protecting the rebar against corrosion caused by chloride ion attack. Due to the degree of permeability and low porosity in the sample containing 100% slag, the amount of corrosion in this mixed design specimens, is the lowest compared to other mixed designs.

Experimental study on effect of replacing pumice and fly ash on the durability of alkali-activated slag concrete Keywords:

Alkali-activated slag concrete , Durability , Corrosion , Low calcium fly ash , Pumice powder.