Utilization of fly ash from the bargny coal-fired power plant in cement matrix structures under mechanical stress

The objective of this work is to valorize unconventional fly ash from the Bargny coal-fired power plant in order to address issues related to the durability of cementitious structures, but also to provide economic and environmental solutions related to industrial waste storage. To this end, an experimental study was conducted to characterize the materials used, in particular the physicochemical and mechanical properties of fly ash, Dangoté cement, and manufactured cement in which clinker is replaced by fly ash at different levels (0%, 5%, 10%, and 20%), as well as a complete identification of aggregates (sand, basalt, flint, and limestone) for hydraulic concrete. First, the results show that the ashes studied are siliceous, spherical in shape, and have a Blaine specific surface area equal to 4126 cm²/g. In addition, the activity indices found, with values of 77% and 96% at 28 days and 90 days respectively, show that the ash is pozzolanic according to the specifications of standard (1). Furthermore, the use of these fly ashes as a substitute product increases the Blaine specific surface area of the cement produced, and therefore its workability, and the mechanical strengths at 28 days are higher than the characteristic strengths given by the standard (3) for a substitution rate of up to 20%. The durability study proves that the use of ash results in fewer connected pores accessible to water in the material.