Influence of Superplasticizer and Alkali Activator Concentration on Slag-Flyash Based Geopolymer

摘要

Sustainable supplementary cementitious material is the prime need in the construction industry. Geopolymer has strong potential for replacing the conventional Portland cement used in mortar and concrete in the industry. This study deals with experimental investigations performed on geopolymer mixes prepared from both ultra-fine ground granulated blast furnace slag and flyash in a certain proportion. Geopolymer mixes were prepared with alkali activator composed of sodium hydroxide solution and varying amount of superplasticizer. The mixes were tested to study fresh and hardened state properties such as setting time, workability, and compressive strength. Influence of concentration of alkali activator on effectiveness of superplasticizer in modifying the properties of geopolymer mixes was also investigated. Results indicated that addition of superplasticizer to ultra-fine slag-flyash based geopolymer is advantageous in terms of setting time, workability, and strength performance but up to certain dosage level. Higher concentration of alkali activator render ineffectiveness in superplasticizer in improving the fresh and hardened state properties of geopolymer mixes.