Highlighting of Design and Mechanical Behavior of Adobe Clay Bricks Made with Biomass Waste

This work focuses on the design and the study of mechanical behavior of new adobe clay bricks material made from local ecological materials for use in construction. The hydraulic binder used is a clay mineral material from the Sibang district in Gabon, and the biomass consists of sawdust from tropical wood species (okoume) combined with additives such as sugar cane molasses and cassava starch. The sawdust comes from okoume, where the selected protocol is based on their availability and widespread use locally. Preleminary tests done on clay show detailed analyses using laser granulometry, chemical analysis of major elements in total rock, X-ray diffraction on total rock and oriented samples (normal and heated to 550°C and ethylene glycol), infrared spectroscopy, cation exchange capacities, and scanning electron microscopy. The mixture of sawdust from okoume, padouk, azobe specie and 85% Sibang clay allowed for the design of bricks with quality facades. The respective compression strength tests resulted in 6.44 MPa, 3.15 MPa and 3.13 MPa, where the mixture containing the okoume sawdust showed a resistance, of 6.44 MPa, two times higher than the others. The adobe bricks incorporating sawdust from okoume, padouk and azobe woods are in compliance with the French standard for compressed earth blocks. The sawdust-wood mixture combined with clay is an ecological material and an alternative to the use of traditional concrete blocks in Gabon.