General Contractor Practice Exam

What is the purpose of the ribs on deformed rebar?

1. Increase bond between concrete and steel

2. Enhance tensile strength

3. Facilitate easy installation

4. Reduce corrosion

The correct answer is: Increase bond between concrete and steel

The primary purpose of the ribs on deformed rebar is to increase the bond between the concrete and steel. When concrete is poured around the deformed rebar, the ribs create a mechanical keying effect that anchors the steel within the concrete matrix. This enhanced bond is crucial for ensuring that the two materials work together effectively under load, allowing the concrete to resist tensile forces in which it is weak, while the steel provides the necessary tensile strength. The increased surface area provided by the ribs helps in preventing slippage between the rebar and the concrete, leading to improved overall structural integrity. Other options may refer to important aspects of rebar or concrete construction. For instance, enhancing tensile strength pertains more to the material properties of steel itself, while facilitating easy installation relates to the handling characteristics of smooth versus deformed rebar. Reducing corrosion is also important for the longevity of rebar, but the ribs specifically do not serve this purpose; rather, protective coatings or the use of stainless steel rebar typically address corrosion concerns.