The Study of Soil Chemistry in the Guinean Coastal Zone

Abstract

The present study focuses on the particle size and chemical characteristics of three types of soils: Kénendé, Limbita 1 and Limbita 2, with a view to their use in the manufacture of mud bricks. Particle size analyses reveal that the soil of Kénendé contains 16% gravel, 49% sand and 35% silt and clay, while Limbita 1 has a high gravel content (31.2%) and Limbita 2 a high proportion of sand (47%) and fines (51%). The latter composition is favourable to the cohesion, good drainage and mechanical resistance of the bricks. On the other hand, the high gravel content of the soil of Limbita 1 could compromise the strength of the material if no fines enrichment is envisaged. Chemically, all three soils have an acidic pH (5.5 to 5.8), below the recommended standards (6.5 to 8.5), which can affect the performance of the binders. Temperatures of 26˚C to 27˚C are favourable for the solidification of materials. Electrical conductivity and dissolved solids reveal a slight salinity at Kenendé and Limbita 1, and almost zero at Limbita 2. Chloride and sulphate levels are particularly high in Kénendé, posing a risk of efflorescence and deterioration of the bricks. In conclusion, the floor of Limbita 2 is the most suitable, both physically and chemically, for the manufacture of sustainable bricks. The soils of Kénendé and Limbita 1 require corrective treatments.