Steel Rebar

Concrete, while highly durable under compressive stresses, is inherently limited in tensile capacity. This disparity arises from the material's brittle nature and low tensile strength, which makes it prone to cracking under flexural or tensile loads. Reinforcement with steel rebar, possessing high tensile strength and ductility, addresses this limitation by effectively absorbing and distributing tensile stresses within the structural matrix. When combined, the rebar-concrete composite material benefits from the compressive strengths of concrete and the tensile resilience of steel, allowing for a significant enhancement in load-bearing capacity and structural integrity. Additionally, rebar provides confinement, reducing potential deformation, and imparts ductility, which is essential in resisting dynamic loads and seismic activity. This synergistic relationship between concrete and steel rebar is critical in maintaining long-term durability and reliability in reinforced concrete structures.  

Foam composites reinforced only with glass reinforced fibre are equally brittle and prone to cracking; for epoxy, vinyl ester and polyester resin to reach the impact and tensile resistance needed for the boats, planes and rockets it is used; multiple layers are needed. To reduce this need steel mesh and steel rebar is used for the same reason it is used in structural concrete.