Abstract
A raw clay material from Burkina Faso has been characterized for pozzolan elaboration. The analysis showed that
SiO2 (45.91 wt. %), Al2O3 (28.29 wt. %) and Fe2O3 (9.75 wt. %) are the main oxides and kaolinite (71 wt. %) is the principle mineral. The sample has been activated at 680 °C during 2 or 5 hours. The pozzolanic activity has been accessed by coupling several methods. The chemical methods showed the good lime fixing ability by the activated sample. At the first 24 hours, more than 50 wt. % of the lime is fixed and at 28 days around 90 wt. % of lime are fixed. Mineralogical analyses showed the disappearing of portlandite (CH) and the formation of new C-S-H hydrates. The pozzolanic index (81 %) calculated from mechanical strength of mortars made with 25 wt. % substitution of cement by the pozzolan confirm it suitability for portland cement replacement in the field of building materials.