Production of fly ash-based geopolymer bricks through geopolymerization process

• Main Author: Wan Mastura, Wan Ibrahim
• Format: Thesis
• Language: English
• Published: Universiti Malaysia Perlis (UniMAP) 2014
• Subjects: Fly ash (FA); Geopolymer; Brick; Geopolymerization
• Online Access: http://dspace.unimap.edu.my:80/dspace/handle/123456789/33150
• Institution: Universiti Malaysia Perlis

Utilization of fly ash as a raw material for geopolymer brick production seems to be a logical solution that allows for the conservation of natural resources, abates further pollution and preserves the environment. Fly ash-based geopolymer have been studied by several researchers worldwide for several decades due to their excellent mechanical properties. Geopolymer is a type of amorphous alumino-silicate material which can be synthesized by polycondensation reaction of geopolymeric materials, and alkali solutions. This study has been conducted to produce fly ash-based geopolymer bricks by means of pressure forming without firing procedure and low energy consumptions. The experiments were conducted on fly ash-based geopolymer bricks by varying the ratio of fly ash-to-sand (1:2 - 1:5, by mass of ratio), curing time (1 - 24 hours) and curing temperature (room temperature - 80°C). Compressive strength, water absorption, dimensional test and density analysis was set as the mechanical properties to be tested on the fly ash-based geopolymer bricks. The compression test and water absorption test were measured at 1, 3, 7, 28 and 60 days. Results of the investigation indicated that there was decrease in compressive strength when the ratio of fly ash-to-sand increase. However, the strength was increased with increase in curing time and curing temperature. Compressive strength up to 20.3 MPa was obtained with curing at 70 °C for a period of 24 hours at 60 days of ageing. The density of geopolymer bricks ranged between 1800 Kg/m3 to 1950 Kg/m3. The microstructural properties of fly ash-based geopolymer bricks were investigated by using XRD and SEM analysis.