Performance assessment of geopolymer building bricks incorporating sanitary ware sludge waste

Abstract

The sludge waste from a sanitary ware production line was used in the manufacturing of geopolymer bricks. The sludge was first dried and then fired at 800ºC. The fired powder was characterized using XRF, XRD, Particle size analysis. Caustic soda and slaked lime were used at percentages of 1% and 6 – 10% respectively. The waste was mixed with the caustic materials in molds whereby geopolymerization took place to produce the required bricks. After four weeks of curing, the produced bricks were tested for their physic-mechanical properties It was found that the compressive strength increased with the degree of geopolymerization and that the properties of the obtained bricks generally conformed to ASTM C 62 / 2017 standard for mixes consisting of 0.5% NaOH, 6% Ca(OH)2 and 45% water. These results were confirmed by SEM imaging.