Effect of Curing Temperature on Properties of Compressed Lateritic Earth Bricks Stabilized with Natural Pozzolan-Based Geopolymer Binders Synthesized in Acidic and Alkaline Media

The present work aims to evaluate the curing temperatures on the engineering and structural properties of the compressed earth blocks (CEBs) produced using natural pozzolan-based acid and alkali-geopolymers as alternative binders. A fixed 15 wt% of binder made with both acid and alkaline solution and natural pozzolan was used to stabilize the laterite soils. Prior, the 7 days aged pressed samples were oven-cured at 45, 55, 65, and 75 & DEG;C for 2 days before covering and storing at room temperature for 28 days. The obtained products were subjected to physicochemical, mechanical, structural and microstructural characterizations. These include optical microscopic (OM), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), percentage of water absorption, dry and wet compressive strengths, and capillary rate flow. The results revealed that the acidic binder was more efficient for the stabilization of the blocks compared to the alkaline one. The values of the dry compressive strength were 17.48, 26.50, 26.00, 25.00, and 25.00 MPa, and 9.36, 9.75, 11.64, 10.08, and 9.00 MPa at 25, 45, 55, 65, and 75 & DEG;C for the acidic binder stabilized block and alkaline binder blocks, respectively. Furthermore, at 45 and 55 & DEG;C in acid and alkaline mediums, respectively, the lowest capillary rise values of 3.30 and 6.25 for acid-stabilized and alkaline-stabilized CEBs were recorded, making this value the optimal temperature for the consolidation process during the stabilization of CEB-based lateritic using the alternative activating binder. However, curing temperatures above 45 & DEG;C for the acidic-stabilized CEBs and 55 & DEG;C for the alkaline-stabilized CEBs reduce the mechanical performance of the end products.