Experimental study on Alkali Activated Fine Aggregate in mortar and Masonry Blocks

Abstract

The present study focused on development of Alkali Activated Fine Aggregate (AAFA) by palletization method. AAFA were manufactured using Ground Granulated Blast Furnace Slag (GGBS) and alkali activator solution at ambient conditions. Sodium hydroxide of six molarity and sodium silicate to sodium hydroxide ratio of 2.5 was used. The alkali activated fine aggregates were prepared using a drum mixer by maintaining a certain rotation angle and speed. AAFA processed a rough texture. The flow properties of the plastering mortar (1:3) were studied by replacing sand by Alkali activated fine aggregate. Mortar cubes were tested to determine the characteristics of alkali activated fine aggregate mortar. Compressive strength and modulus of elasticity of the mortar were evaluated at the age of 28 days. Results indicate that speed of the mixer influence the properties of alkali activated fine aggregate. AAFA exhibited lower specific gravity, high water absorption, and lesser bulk density compared to manufactured sand. The flow of mortar increases by increasing the percentage of Alkali Activated Fine Aggregate, up to a 60% replacement of M-sand for a water cement ratio of 1.3. Beyond 60% replacement, there is a bleeding in the mix. The compressive strength of Alkali activated Fine aggregate mortar gives consistently optimum compressive strength up to an 80% replacement of AAS by M-sand. The manufactured aggregates were found to be suitable in making plaster/masonry mortar and for making masonry units.