Compressive Strength of Geopolymer Concrete: A Review of Alkali/Binder Ratio, Binder Type and Curing Conditions

YILDIRIM, Salih Taner; YILMAZOGLU, Arif; HILAL, Nahla; SOR, Nadhim Hamah

doi:10.22059/ceij.2026.401523.2378

Compressive Strength of Geopolymer Concrete: A Review of Alkali/Binder Ratio, Binder Type and Curing Conditions

Articles in Press

Document Type : Review Paper

Authors

Salih Taner YILDIRIM ¹

Arif YILMAZOGLU ¹

Nahla HILAL ²

Nadhim Hamah SOR ³

¹ Kocaeli University

² University of Fallujah

³ University of Garmian

10.22059/ceij.2026.401523.2378

Abstract

This study systematically reviews the impact of key parameters such as alkali/binder ratio (ABR), binder type, curing temperature (CT), and curing time on the compressive strength (CS) of sustainable geopolymer concrete (GPC). The analysis reveals that CS increases as the ABR decreases, with a ratio of 0.25 representing a critical level for optimizing both workability and strength. An evaluation of different binders, including fly ash (FA), ground granulated blast furnace slag (GGBS), metakaolin (MK), silica fume (SF), and ferrochromium slag (FS), showed that GGBS delivered superior strength performance. A complete replacement of FA with GGBS resulted in a CS increase of up to 397%. Conversely, adding FA, SF, or MK to GGBS-based mixes reduced CS by 41%, 52%, and 58%, while increasing the initial setting time by up to 200%, 180%, and 120%, respectively. The optimal curing conditions for most GPC mixes were identified as a temperature between 75 and 90°C, maintained for 24 to 48 hours. Notably, ambient temperature curing was found to be unsuitable, especially for Class F FA-based GPC, underscoring the necessity of thermal activation for achieving practical strength development.

Keywords

alkali/binder ratio

binder type

compressive strength

curing temperature and time

geopolymer concrete

Subjects