This article focuses on the evaluation and determination of the geotechnical characteristics of lateritic soils in South-West Chad (Kélo-Pala) with a view to better use in road construction. The study shows that borrowing volumes range from 29374.4 m3 to 87920 m3. The lateral soils studied consist of a mixture of fine particles and gravel with low plasticity. On the physical side, loans have a sieve percentage of 0.08 mm, ranging from 13.7% to 24.8% with an overall average of 18.9%. These values give the soils studied a grainy character. The liquidity limit of the soils studied ranges from 17.2% to 27.4% with an average of 21.17% and the plasticity index ranges from 3.6% to 9.3% with an average of 7%. These results show that the materials studied are noninflating with a small percentage of fine particles. They belong to class A-2-4 according to the HRB classification and class S5 (CBR> 30) according to the LCPC classification. On the mechanical side, the borrowings studied show that the optimal content ranges from 7.3% to 10.1% with an average of 8.55% and the optimal dry density ranges from 2.07g/cm3 to 2.2 g/cm3 with an average of 2.12 g/cm3. The CBR index ranges from 61% to 98% with an average of 79.90%. These results show that the engravers studied belong to class Gl1 and are usable and usable in road construction according to the recommendations of the CEBTP.

The purpose of this study is to determine the dry and wet mechanical resistances after immersion in water of bricks of 15 x 20 x 40 cm3 in sand mortar (cinder blocks) and 10 x 14 x 28 cm3 compressed lateritic mortar bricks (BTC) stabilized with cement. The experimental results obtained show that the 28-day compressive strength values of the 12% cinder blocks and those of the 10% cement Btcs are respectively 2.55 MPa and 7.90 MPa. These values are in accordance with the normative values recommended by the Building Materials Centre (CMC) in N'Djamena (2.4 MPa) and the Land Materials Research Centre (CRATerre) (5 MPa). In the presence of moisture, the loss of resistance is only 28% for BTC and 46% for cinder blocks. Also, the bricks have a suction capacity ranging from 2.50 to 5.02 g/cm² S1/2 for BTC and 6.12 to 10.90 g/cm². S1/2 for cinder blocks. These values are all less than 20 g/cm². S1/2, a value imposed by NF P 554. A comparison of the results of this work shows that, with the same cement content, during dry seasons as in rainy seasons, Btcs are more resistant and more economical than cinder blocks.

Pathological analysis of adobe (banco) constructed habitats in the city of N'Djamena in Chad shows that the most frequent defects observed are, among others, the abundant appearance of cracks, the erosion of external walls, water infiltration and subsidence. At different stages of identification for the choice of material (earth), brick production and its implementation, this work proposes simple and practical solutions to avoid the above mentioned defects resulting from traditional techniques. Thus, geotechnical tests are proposed to identify the right soil, rice bales must replace the straw for earth treatment and finally a foundation system (insulated sole - primer post - underbody wall - sill) of reinforced concrete must be constructed to ensure the stability of the structure.