Correct Response: D. Rebar (short for reinforcing bar) is a steel bar that is added to concrete because of its tensile strength. This combination of concrete and rebar is known as reinforced concrete. Reinforced concrete combines the compressive strength of concrete with the tensile strength of the steel rebar. Since concrete is already extremely strong under compression (A), improving this property is not a primary reason for adding rebar. In fact, adding too much rebar can lead to compression failure because of a mismatch between tensile and compress strength. The adding of rebar has no appreciable effect on curing (B). To reinforce concrete to withstand torsion (C) forces, steel fibers are used instead of rebar.
