Effects of POFA replaced with FA on durability properties of GBFS included alkali activated mortars

Abstract

Concrete durability is a major concern in the construction sector worldwide. Recycled industrial and agriculture wastes based concrete production was shown to be beneficial in terms of enhanced durability performance and environmental friendliness. The effects of palm oil fuel ash (POFA) replacement by fly ash (FA) on the durability properties of ternary alkali activated mortars (AAMs) containing ground blast furnace slag (GBFS) was evaluated. The mixes were designed with six levels of POFA replaced by 0, 10, 20, 30, 40 and 50% (by weight) of FA. Durability properties such as porosity, drying shrinkage, resistances to freezing-thawing cycles, wet-dry cycles, abrasion, sulphuric acid and sulphate attack were investigated. The mortar containing 10% of FA as a replacement of POFA disclosed the best compressive strength amongst all the mixes at the age beyond 180 days. The overall durability performance of the AAMs obtained from POFA replaced by FA displayed an enhancement in porosity as well as dry shrinkage and a reduction in the resistances to freezing-thawing cycles, abrasion, acid and sulphate attack.