Contribution À L'amélioration De La Durabilité Du Béton Dans Les Zones Enterrées De La Wilaya De Ouargla Par L’ajout Des Minéraux Locaux

Résumé: The low of Ouargla facing serious problems that affect durability of concrete of large number of structures, especially those buried lake foundations, paving, pipes etc.... and a several buildings need to be repaired or rebuilt because of their advanced state of deterioration. the southern Algeria is adorned by sand dunes which occupies 6% of its surface, and the previous studies show that the addition of silica fume in concrete improves its strength and durability due to its amorphous structure and its high finesse that gives to it a very good filling capacity, and strong pouzzolanlité, but concrete is still little used because of their high costs because the production of silica fume is limited in industry silicon. The use of sand dune that contains more than 96 % of silica as a proposal would be in reducing costs and improving the durability of underground structures. To achieve our goal we made a similar experimental program with many studies in the same field of study. First we characterize the materials used, after that we study the effect of additions by adding sand dune crushed of Ouargla, and silica fume with varied percentages (0 %, 2 %, 4%, 8%) and we study the effect of cement type on the mechanical properties and on porosity of the concrete in three environment of conservation; standard environment, groundwater environment and water sulphate environment at différent ages. This group of tests confirmed a number of results found in the literature concerning the performance concrete with additions particularly silica fume and its resistivity against sulfate therefore their durability in Ouargla milieu. It also confirms that the CRS is sulphate-resisting cement, so the causes of degradation of buried concrete structure built by CRS come from another source. The addition of 2% crushed sand dune in concrete is an optimal value to improve its strength and durability. Note that the abundance of sand dunes in our area hence the need to take into consideration global interest of the introduction of finely crushed sand dunes in the concrete industry.

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