Development of bricks from a combination of waste plastics, wood dust and sand

Abstract

Every day, Uganda generates over 600 metric tons of waste plastics. Woodworking generates a lot of wood dust in the same country, yet only 10% of it is used locally. This research explored a supplementary measure that sustainably utilizes waste plastics and wood dust to make bricks, which can replace and reduce on the use of cement and sand respectively in brick making. PET waste plastic, pine wood dust and Lake sand specifically were used during this study. By weight percentage, bricks were developed from three distinct mixing ratios of 5:3:2, 2:2:1 and 3:5:2 (waste plastics: wood dust: sand). A rudimentary procedure of melting PET waste in a mini metallic drum and mixing it with wood dust and sand was employed to make bricks with dimensions of 205mm×105mm×65mm. The compressive strength and water absorption of these bricks were evaluated using ASTM D695 – 15 and ASTM D570 – 95, respectively. The greatest and lowest compressive strength values were 8.7 MPa and 1.5 MPa, respectively, and the highest and lowest water absorption values were 9.7 % and 2.1 %, respectively. According to the two-way ANOVA test, the compressive strength values of the bricks made from different mixing ratios (raw material loading) differed significantly (P<0.05), while there was no significant difference (P>0.05) for bricks made from the different wood dust particle sizes. The water absorption percentages for bricks produced of varying mixing ratios and wood particle sizes differed significantly (P<0.05) in the same test. The compressive strength increased as wood dust content and particle size decreased while water absorption increased as the wood dust content and particle size increased. The investigated parameters improved as the PET waste wt % increased, and the same was true for the constant sand wt %, while the wood dust content had the opposite effect. The manufactured bricks have the potential to be used in both load-bearing and non-load-bearing structures, as a result of the acquired outcomes and observations made during the short-term assessment.