What is the defining characteristic of prestressed concrete?

The defining characteristic of prestressed concrete is the application of an initial compression load. This process involves introducing compressive stresses in the concrete before it is subjected to working loads. By doing so, the internal stresses counteract the tensile stresses that occur when the concrete is put under load, particularly in areas where tension may develop. This enhances the concrete's ability to bear heavier loads and reduces the risk of cracking due to tension.

Prestressing is typically achieved through techniques such as pre-tensioning, where steel tendons are stretched before the concrete is cast, and post-tensioning, where tendons are tensioned after the concrete has cured. This initial compression is fundamental because it helps to improve the structural performance of the concrete while also enabling longer spans and thinner sections than conventional reinforced concrete.

Other options do not encapsulate what makes prestressed concrete distinct. While increased resistance to tension might seem relevant, it does not define prestressed concrete in the same way that the initial compression load does. The use of lightweight aggregates or being similar to standard concrete does not relate specifically to the characteristics that define prestressed concrete.