What technique is used in partial prestressing to mitigate cracks in concrete structures?

In partial prestressing, the primary goal is to enhance the structural integrity and longevity of concrete structures while controlling cracking under service loads. Incorporating rebar into the mix is a widely recognized method to achieve this.

Rebar, or reinforcing steel, works by providing tensile strength to the concrete, which naturally has high compressive strength but low tensile strength. When the concrete is subjected to tensile stresses, the embedded rebar can help absorb those forces, thereby reducing the likelihood of cracks. The combination of prestressed tendons and rebar allows for a more balanced approach, where the prestressed anchors tension in the concrete, while the rebar helps manage potential cracking when the structure is in use.

The other options, while they may have their own benefits in specific contexts, do not directly address the fundamental mechanics of crack mitigation in the same way as incorporating rebar does. Surface sealants primarily serve as a protective barrier rather than a structural reinforcement, high-strength fibers can increase toughness but do not provide the same level of crack control as rebar, and reducing water content mainly affects workability and strength development but does not specifically target cracking mitigation. Thus, incorporating rebar is the most effective technique within the framework of partial prestressing for controlling cracks.