Which type of concrete uses high tensile strength steel strands as reinforcement?

• A. Reinforced Concrete
• B. Post-Tensioned Concrete
• C. Prestressed Concrete
• D. Precast Concrete

Answer: (C)

Prestressed concrete uses high-tensile steel strands to introduce compressive forces into the concrete before it takes loads. By tensioning these strands (either before the concrete is poured or after it has cured), the member remains in compression under service loads, which greatly reduces cracking and allows longer spans and lighter sections. This is why identifying the use of high-tensile strands points to prestressed concrete.

Reinforced concrete relies on ordinary steel reinforcement to resist tensile stresses after cracking, not to pre-compress the member. Precast refers to the manufacturing method, not the reinforcement approach, though prestressing can be used in precast elements as well. Post-tensioned concrete is a form of prestressed concrete where the tendons are stressed after the concrete has hardened, which is a subset of prestressed concrete.