Prestressed concrete is made by embedding strands of high-strength steel into the concrete. Prestressed concrete plants have the equipment to carry out this hefty task.
Prestressed concrete found its fame during the European reconstruction after World War II. The construction of prestressed concrete was an engineering feat that allows for lighter and more shallow concrete structures without losing any of the strength. Many limitations that engineers faced in the past when designing concrete structures were able to be surpassed with the advancement of prestressed concrete.
The steel strands are stretched before being placed into the mold. The steel strands are then stretched to nearly 80 percent of their ultimate strength, which is around 30,000 lbs. of added tension and, once this is achieved, the concrete is poured on top. Once the concrete is at its needed strength, the steel tendons are released from the abutments that stretched them and, as the steel regains its original length, tension is applied to the concrete itself, creating more stress and strength.
Prestressed concrete is commonly used in commercial building wall panels, piles and bridge girders. This type of concrete is ideal because of its flexibility due to the internal steel tendons.