Assessing the suitability of fly ash and rice husk ash from Misamis Oriental, Philippines in producing bricks for pedestrian and light traffic applications

Fly ash (FA) and rice husk ash (RHA) are agro-industrial wastes generated continually thereby requiring sustainable and environment-friendly ways in the treatment process. This study aimed at assessing the suitability of FA and RHA from Misamis Oriental, Philippines in producing bricks that can possibly be used for pedestrian and light traffic purposes. Quantitative experimental method was used in the study. Bricks were manufactured utilizing 40 to 95% Class F-type FA, 0 to 55% Class F-type RHA, 5% bentonite as the binder, 800？C-firing temperature and 4-8 hours-firing time. Scanning electron microscopy (SEM) was used for morphological characterization of the bricks. % FA utilization was directly proportional to compressive strength of the bricks but inversely with water absorption, abrasion resistance and saturation coefficient. % RHA utilization was inversely proportional to compressive strength but directly proportional to the other mechanical properties. Firing time had no effect at all. SEM revealed that internally, bricks were combination of spherically and irregularly-shaped particles. Parameters used produced bricks but not suitable for pedestrian and light traffic purposes. It is recommended to increase the firing temperature and vary other parameters in the production such as %water added, number of days of air drying, molding pressure among others.