Improving the essential characteristics of Lake Chad diatomaceous earth for the ecological construction.

Abstract

In the Lake Chad region, diatomaceous earth is the type of soil that is easily accessible, but its use for construction presents challenges due to its specific characteristics.  This study aims to characterize the physico-chemical and mechanical properties of these soils after adaptive treatment, consisting to add a small amount of lime.  The X-ray diffraction reveals a composition of 73% quartz, 2.3% kyanite, 21% carbon and 1.58% of other minerals.  The measured pH is 8.3, indicating this diatomite soil can be stabilize.  Stabilized and Compressed Earth Blocks (SCEBs) were molded using six formulations (0% of lime added, 2%, 4%, 6%, 8% and 10%) and cured in three groups (groups of 7, 14 days and 30 days). The measure of their compressive strength denotes the SCEBs without lime, after 30 days of curing, show strength of 2 MPa and the SCEBs with 10% of lime exhibit a high compressive strength of 4.27 MPa, according to several standards of Compressed Earth Blocks. Thus, the addition of lime allow for the production of quality SCEB for construction. Regarding thermal properties, experiments on SCEBs show that thermal conductivity decrease with the addition of lime, from 0.194 W/m.°C to 0.370W/m.°K, and remain widely above 0.065 W/m.°K which is good value for thermal insulation. Finally, above 4% of lime, the mass loss (0.24%) is negligible