ReinforcedConcrete

Concrete is the most widely used construction material in the world. Its evolution into reinforced concrete, introduced at the end of the 19th century, revolutionised modern architecture by allowing the tensile structural limits of artificial stone to be overcome.

The base mix consists of a hydraulic binder (generally Portland cement), stone aggregates of various grain sizes (sand, gravel) and water. The addition of chemical admixtures — plasticisers, air-entrainers or retarders — makes it possible to modify its rheological properties when fresh and its performance once hardened.

The hardening process does not occur by drying, but through a complex exothermic chemical reaction known as cement hydration, which gives the matrix its characteristic hardness and mechanical strength over time.

The success of reinforced concrete (RC) rests on two principles: the compatibility of the thermal expansion coefficients between steel and concrete (almost identical) and the highly alkaline environment (pH ~13) generated by the cement, which protects the steel reinforcement from oxidation (passivation).

To ensure durability, it is essential to design a correct concrete cover, i.e. the layer of concrete that separates the reinforcement from the external environment, protecting it from carbonation and chloride attack.