This study focuses on the mineralogical, geochemical and petrographic characterization of three granite rock samples (LTP, LTS and LTMB) from Foumban, West Region of Cameroon. Fusibility tests were carried out on the samples containing the highest amount of alkali to assess the potential of these materials as fluxing admixture for ceramics. The results show that the granite consists of alkaline feldspars, notably orthoclase and microcline of perthitic micro-texture, plagioclases (in particular albite) and also mafic minerals such as amphibole and pyroxene. The quantity of alkali in the samples is quite high (16.83% for LTS, 17.08% for LTMB and 18.87% for LTP) compared to standard data. Fusibility tests carried out on the samples having the highest alkali content (LTMB and LTP) showed that the vitreous phase appears between 1050˚C and 1100˚C in these samples when they were heated. The Fe 2 O 3 and TiO 2 content of LTMB (3.01% and 1.49% respectively) led to a brown colour of its fired product. Therefore, based on their composition, these materials can be used as feldspathic fluxes for the formulation of ceramic products.

The present work consists of a statistical study of the properties of the soils of the locality of Monatele used for the confection of compressed and stabilized earth bricks by calcination. This study is based on sixteen (16) samples taken from four (04) sites, namely, Nkolossananga, Nkol-Medock, Avoh, and Enieg. The results of the chemical and mineralogical tests show that the soils sampled are composed of quartz, Kaolinite, Hematite, Muscovite, Calcite, Rutile, Pyroxene, Montmorillonite, and Illite, with variable proportions. The water content of these soils varies from 10.32 to 26.35%. The granulometric analysis supported by Methylene Blue reveals dominant proportions of clay ranging from 32.8 to 53.7%. The plasticity test shows that the studied soils are almost essentially medium plasticity clays and high plasticity clays depending on the case. The HBR classification identifies them as clayey and silty soils belonging to classes A-7-6 and A-5. The physical-mechanical tests carried out on the fired brick specimens show that the density decreases with the increase of the temperature, while the water absorption, the flexural strength, and the compressive strength increase under the same conditions. The statistical study of the studied properties shows good correlations between the different granular classes present in the studied soils. In particular-0.79 between the proportions of gravels and silts and-0.68 between sands and clays. The values of methylene blue and plasticity also show interesting correlations with the percentage of silt, namely, 0.52 and 0.54, respectively. The Pearson correlation matrix also reveals that mechanical strength, water absorption, density, and firing temperature show good correlations with each other. These allow for the establishment of predictive models for compressive strength with a correlation coefficient R 2 = 0.83.

In order to promote the use of calcined clays and volcanic scoria from the western Cameroon as Supplementary Cementitious Material (SCM), the physical, chemical and mechanical properties of fresh and hardened cements were investigated. The cement was formulated by substituting 10, 20, 30, and 40% of clinker by calcined clays from Mayouom (Mkm) and Balengou (MKb), and volcanic scoria from Foumbot (PNf). For each of the three raw materials, the loss on ignition is less 1%, the sum %SiO 2 + %Al 2 O 3 + %Fe 2 O 3 is greater than 70%, amorphous phase is present and pozzolanic reactivity with the Chappelle test is greater than 80% of Ca(OH) 2 consumed. This makes it possible to classify MKm, MKb and PNf among the pozzolanic materials. The addition of calcined clay to the clinker, result to an increase in the water to cement ratio, unlike the Foumbot pozzolan, which does not really affect this ratio. The three raw material act as setting retarders, with PNf having a greater retarding effect than MKm and MKb. The compressive strengths of the cements formulated in this study shows that with 10% clinker substitution, cements of class 42.5 can be obtained, and that from 20% onwards, the cements obtained are of class 32.5. However, an addition of more than 20% PNf in the clinker produces cements with strength less than 30 MPa at 28 days. Calcined clay from Balengou and Mayouom could be used as a viable alternate source of SCM for cement production with better performances compared to volcanic scoria from Foumbot.