EFFECTS OF STABILIZERS ON THE MECHANICAL PROPERTIES OF A CLAY USED IN ECO-CONSTRUCTION

Earthen building materials are attracting renewed interest due to the high cost of binder-based construction materials such as cement. Added to this is the environmental pollution caused by their production. To reverse this trend, current research efforts are focusing on developing and improving the mechanical properties of earth-based materials and stabilizers, commonly referred to as eco-materials. Against this backdrop, we manufactured Guinea clay bricks using the following formulations: clay + lime (5 % and 10 %), clay + fibers (0.25 %, 0.5 % and 0.75 %), and clay + lime + fibers (ratios 8/0.35 % and 12/0.35 %), and studied their physical and mechanical properties after 14 and 28 days. The results show an increase in the compressive and flexural strength of the bricks.
The formulation with the best performance was that with 12 % lime and 0.35 % fiber, with compressive and flexural strength values of 9.14 MPa and 2.10 MPa, respectively, after 28 days of drying. This formulation is comparable to mortar made with 9 % CEM I 42.5 R cement, mixed with soil containing 30 % clay and silt, 40 % sand, and 30 % gravel, with optimum moisture content and cured for 28 days, reaching 9.30 MPa.  Our study shows that clay bricks with 5% lime at 28 days are lighter in bending, with an apparent density of 1.8 g/cm³, compared to bricks obtained with the other two formulations and those made of natural clay.