Effect of Plasticizer and Superplasticizer on Rheology of Fly-Ash-Based Geopolymer Concrete

摘要

An attempt has been made in this investigation to study the variation of yield stress, plastic viscosity, and slump of fly-ash-based geopolymer concrete with the variation of lignin-based plasticizer dosage and polycarboxylic-ether-based superplasticizer dosage. It has been observed that a critical value of molar strength of sodium hydroxide exists that is equal to 4 M. Beyond this critical molar strength, superplasticizer and plasticizer have an adverse effect on yield stress, plastic viscosity, and slump offly-ash-based geopolymer concrete. Below the critical molar strength of sodium hydroxide, there is a decrease in both the rheological parameters and an increase in slump. Lignin-based first-generation plasticizer shows better performance in terms of workability over third-generation superplasticizer below the critical value of molar strength. It was also observed that there is a good correlation between the rheological parameters and slump for fly-ash-based geopolymer concrete incorporating plasticizer and superplasticizer.