This research work is part of a dynamic to support the structural transformation of the Beninese economy and the fight against global warming by valorizing certain mineral resources in the cement industry. The project focuses on the possibility of using metakaolin produced from Kétou kaolins to make blended cements. Following a physico-chemical and environmental characterization of the metakaolins, we determined their pozzolanic reactivity and their mechanical activity index. The results show that the pozzolanicity of metakaolins produced from Kétou kaolins is relatively slow compared with that of portland cement. On the other hand, they can be considered as a type II mineral addition according to EN 206-1, with an activity index of 0.87. This is why we used them to produce five compound cements. Analysis of these cements shows that their strength class remains identical to that of conventional portland cement when the substitution rate remains below 20%. Mortars were produced from these cements and characterized both physically and mechanically. The final conclusion is that Kétou metakaolins can be incorporated as an addition in the production of blended cements. The mechanical properties of mortars made with these cements are better than those of portland cement when the substitution rate does not exceed 10%. The production of compound cements with metakaolins could therefore generate potential gains in the cement industry, since their production is less energy-intensive than that of conventional portland cement. Keywords: cement, metakaolin, mortar, pozzolanic reactivity
BORIS GANMAVO, VALERY K. DOKO