Engineering and Applied Science Research (Jul 2022)
Pozzolans: A review
Abstract
Natural and artificial pozzolans are widely used in building materials and play an increasingly important role in minimizing costs and mitigating environmental effects in the manufacturing of building materials. These pozzolans can be obtained as by-products from various industries, generally they are wastes without any application or added value. However, when implemented in cement mixtures, their effectiveness is somewhat questionable. Therefore, it is necessary to determine the properties, characteristics, and behavior of these materials. This study aims to summarize the main pozzolans used in building materials. Volcanic pozzolans, pozzolans of sedimentary origin, fly ash, blast furnace slag, silica fume, metakaolin, ceramic wastes, demolition, and construction wastes, rice husk ash, bagasse ash, biomass ash, and paper sludge were considered. The chief characteristics studied were particle size, specific area chemical composition, and mineralogical composition. In addition, the impact on mechanical properties and durability in cement mixtures using pozzolans was analyzed. It was observed that the mechanical properties of cement mixtures change by increasing pozzolan replacement. The maximum percentage of replacement depends on the characteristics of the pozzolan. In the case of durability, pozzolans decrease absorption and permeability by reducing the porosity of the binder. This decreases acid diffusion and autogenous shrinkage, thus improving concrete durability. Finally, future studies are suggested to consider the implementation of artificial intelligence techniques and machine learning algorithms to improve the properties of the concrete mixtures.
