The impact of alkaline solution to fly ash ratio with different molarities of sodium hydroxide on self-compacted geopolymer concrete

This study article examines the effect of changing the alkaline solution to flash ratio on the strength and workability of a self-compacted geopolymer concrete mix, including fly ash. To create geopolymer concrete mixes, a ratio of alkaline solution to fly ash of 0.6, 0.7, and 0.8 is utilized, while the ratio of sodium silicate (Na2SiO3) to sodium hydroxide (NaOH) remained constant at 3. A sodium silicate (Na2SiO3) mixer with three sodium hydroxide molarities (10 M, 12 M and 14 M correspondingly) has produced the alkaline solution. The specimen was cured at 80 degrees Celsius for 24 h and kept at room temperature until testing. The experimental results suggest that when the ratio of alkaline solution to fly ash increases, the workability of geopolymer concrete rises, but the compressive strength falls. Therefore, alkaline Solution to Fly Ash ratio of 0.6 to 0.7 is most likely recommended for self-compacting concrete mixing and hardening property of fresh geopolymer concrete. Additionally, it is demonstrated that increasing the sodium hydroxide dose decreases the workability of fresh concrete but increases the compressive strength. Copyright (c) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials, Processing & Characterization.

Automated summary

This study examines the impact of changing the alkaline solution to fly ash ratio on the strength and workability of self-compacted geopolymer concrete. The results suggest that increasing the ratio of alkaline solution to fly ash improves workability but reduces compressive strength. Therefore, a ratio of 0.6 to 0.7 is recommended for optimal self-compacting concrete mixing and hardening of fresh geopolymer concrete.