The study presents an appropriate soil recognition process for the production of reliable compressed earth bricks (CEB) in Pala, Mayo-Kebbi West. Samples were collected from the quarries of Goub-goub, Madagascar, Yatilim, Sara and subjected to on-site and laboratory identification tests. After analysis and interpretations of the results, it emerges that the red grainy soil made up of a silty earth taken from the site of Sara is the ideal soil for the earth construction. This soil makes it possible to obtain a good compaction because it is naturally well graded (Cu = 14.40 and Cc = 1.37) and it is little plastic (IP = 13.60) so little sensitive to bad weather. Soil of hard consistency (IC=2.68), it is difficult to scratch with the thumbnail. Also, by stabilizing it with 9% of the rice bran by simple compression in a press of 5 to 10 kN, its compression resistance (CR) after cure of 28 days approaches 11.80 MPa, value between 5 MPa and 20 MPa; an interval required by the International Center for Earth Construction, CRA terre. To be eligible, soil samples from the other three quarries must undergo granular changes by adding missing grain sizes or by reducing/eliminating excess grain sizes so that these soils are reduced to well graded and little plastic. And if there are cracks and/or volumetric changes on bricks made with these types of soils, the present study reveals that a reasonable proportion of mineral, plant or animal binder must be added. Finally, whether it is perfect for construction or not, the earth remains the most desired material by users because, apart from its countless technical, ecological and economic qualities, it also integrates our cultural heritage.

The most used bricks in house building in NDjamena, city of Chad which is situated in semi dry arid area with 600 millimeters of pluviometry per year and 50 °C as highest temperature, are raw clay bricks, terracotta bricks or bricks in ciment block. The raw clay bricks have strong sensibility in water and weak resistance to compression. The terracotta and cement block bricks have high thermal conductivity contrary to the adobe and their manufacturingcontribute to destroy the environment. The aim of this paper is to search Stabilised Earth Block (SEB) bricks whichare made with clay, sand and few percent of cement and respond to climatic, environmental and economic constraints. Therefore, some bricks are built in mixing differentspercents of sand and clay (M1 : 40% sand and 60% clay, M2 : 50% sand and 50% clay, M3 : 60% sand and 40% clay, M4 : 70% sand and 30% clay, M5 : 30% sand, 30% slime and 40% clay, and M6 : 40 % sand, 20% slime and 40% clay) for obtaining physical stabilizationand adding 8%, 10% or 15% of cementin each type of brick for the chemical stabilization. Theuse of moulding press machine grants already the mechanical stabilization to these bricks. Proctor test has allowedto retain M1, M3 and M4 for searching the best values of the rate absorption of water by capillarity , the resistance in compression and the thermal conductivity of these bricks. The results of tests show bricks M3 with 10% of cement have the good values 21,23 g.cm-².min-1/2 of rate absorption, 3,82 MPa of resistance in compression and 0,5W.m-1.°K-1 as thermal conductivity.

Reinforced concrete (RC) constructions are the innovation of sustainable constructions replacing masonry constructions. Despite this, the use of concrete and steel to improve the performance of structural members in service is a recurring problem due to the immediate or overtime appearance of cracks. The objective of this work was therefore to assess the damage phenomena of the steel-concrete interface in order to assess the performance of an RC structure. Samples of approximately 30 cm of reinforcement attacked by rust were taken from broken reinforced concrete columns and beams in order to determine the impact of corrosion on high adhesion steel (HA) and therefore on its ability to resist. The experimental results have shown that the corrosion degradation rates of reinforcing bars of different diameters increase as the diameter of the reinforcing bars decreases: 5% for HA12; 23.75% for HA8 and 50% for HA6. Using the approach proposed by Mangat and Elgalf on the bearing capacity as a function of the progress of the corrosion phenomenon, these rates made it possible to assess the new fracture limits of corroded HA steels. For HA6 respectively HA8 and HA12, their initial limit resistances will decrease by 4/4, 3/4 and 1/4. Based on the results of this study and in order to guarantee their durability, an RC structure can be dimensioned by taking into account the effects of reinforcement corrosion.

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