Durability of concrete containing a natural pozzolan as defined by a performance-based approach

This paper deals with the application of a performance-based approach on the durability of concrete made with an Algerian natural pozzolan. The evaluation of the durability of concrete was based on the comparison of durability indicators with a reference concrete usually found in Algeria. The properties measured included general indicators (water porosity, gas permeability, capillary absorption and Portlandite content) and specific indicators related to degradation phenomena that might occur in Algeria: corrosion induced by carbonation and chlorides, and chemical attacks by sulphates and acids. For the specific degradations, the indicators measured included carbonation depths, chloride diffusion coefficients, chloride permeability, expansion and sulphate profiles, and depth of leaching due to ammonium nitrate attack. The results showed that general durability indicators were almost equivalent for all the types of concrete tested, highlighting the importance of using specific indicators for each type of exposure. The results of specific indicators for corrosion and acid attacks showed that increasing the pozzolan content led to higher resistance of the concrete. Thus, it is possible to improve the durability of typical concretes currently made in Algeria by using local materials.