**3. Conclusion**

This chapter mainly reviews FA as basic raw materials, which can be introduced in the production of concretes so-called geopolymer concrete. As per several reports, a huge quantity of FA is disposed and landfilled. Besides, it has been estimated that the cement industry contributes approximately 7% of global warming, due to the substantial increase in carbon dioxide. The raw materials and the manufacturing process of the conventional cement are found to be the main reason behind this increase. As a solution for this serious environmental issue, much research has been conducted to investigate other alternative materials to Portland cement. FA is the most investigated material, due to its suitability and its physicochemical properties including microstructure, reaction mechanism, and characterization as normalized by ASTM C618.

The chemical composition analysis shows that FA consists of a complex oxide mixture of aluminosilicate glasses and other crystalline elements with the presence of the amorphous phase. This latter explains the high reactivity of FA and its suitability as a mineral admixture for cement and concrete.

Numerous studies show that including FA in the production of geopolymers concrete provides a greater mechanical and microstructure properties, due to its physical characteristics compared to that given by OPC. These findings make the use of FA of particular interest to researchers. As a result of the excellent properties, geopolymer-based FA has been successfully applied in various traditional and new applications. It is believed that the progress researches in geopolymers area especially in the utilization of industrial by-products have been intensified and consisted as a significant step to introduce geopolymers technology in the construction industry and particularly in marine applications.
