DefinePK

Abstract

This study investigated the performance of geopolymer bricks that were produced using fly ash, chippings and sodium hydroxide (NaOH) solution. Brick mixtures were designed with solution-to-binder ratio of 0.35. The NaOH solutions of 5, 8, 10 and 12 M were used as alkaline activators. The effect of NaOH concentration on properties of geopolymer bricks, including compressive strength, ultrasonic pulse velocity, thermal conductivity, and electrical resistance was investigated. In addition, the scanning electron microscope (SEM) was also used to observe the microstructure of geopolymer bricks. Test results indicated that the compressive strength, ultrasonic pulse velocity, thermal conductivity, and electrical resistance of geopolymer bricks increased with increasing NaOH concentration. Furthermore, SEM micrographs showed a higher hydrate rate of fly ash in brick samples with higher NaOH concentration. All brick samples investigated in this study exhibited a good quality with compressive strength of above 10 MPa, ultrasonic pulse velocity of above 2500 m/s, and electrical resistance of above 2 k