The main objective of this study is to characterize the physico-chemical and mineral properties of clay materials from Burkina Faso to produce stabilized compressed earth blocks (CEBs). The reactivity of the clay materials was tested based on the electrical conductivity of solutions and the compressive strength of CEBs stabilized with 0-20 wt% CCR (calcium carbide residue) and cured for 45 days at 40±2 °C. Pabre and Kossodo respectively contain the highest fractions of clay (20-30%) and gravel (40%). Saaba and Pabre contain the highest content of kaolinite (60˗70%) and quartz (45-60%) and recorded the highest and lowest reactivity, respectively. The compressive strength of CEBs stabilized with 20% CCR improved tenfold (0.8 to 8.3 MPa) for Saaba and only 2.6 (2 to 7.1 MPa) for Pabre. The clay materials in the present study are suitable to produce CCRstabilized CEBs for load-bearing construction.

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Earth stabilization, using two by-products available in Burkina Faso: Calcium Carbide Residue (CCR) and Rice Husk Ash (RHA), improved the performance of compressed earth blocks (CEBs). The effect of adding CCR or CCR: RHA (in various ratios) to the clayey earth was investigated. CEBs were molded by manually compressing moisturized mixtures of earthen materials and 0-15 % CCR or CCR: RHA (various ratios) with respect to the weight of earthen material. The results showed that, with 15 % CCR: RHA in 7: 3 ratio, the compressive strength of CEBs (6.6 MPa) is three times that of the CEBs containing 15 % CCR alone (2.2 MPa). This improvement was related to the pozzolanic reaction between CCR, clay and RHA. These CEBs comply with the requirement for wall construction of two-storey housing.