Several additives can enhance the strength of concrete, each working in a different way:
Supplementary cementitious materials (SCMs)
These include fly ash, slag, and silica fume. They react with the byproducts of hydration (the chemical process when cement hardens) to form additional cementitious compounds, densifying the concrete and increasing strength.
Superplasticizers
These admixtures improve the workability of concrete, allowing for a lower water-to-cement ratio. Since excess water weakens concrete, superplasticizers indirectly contribute to a stronger final product.
Fiber reinforcement
Steel or synthetic fibers dispersed in the concrete mix improve its tensile strength and resistance to cracking, especially from shrinkage or impact.
