Rebar 1/2" x 20' Grade 40, Rebar is used for concrete reinforcement in projects such as foundations, slabs, patios, driveways, sidewalks, curbing, and swimming pools. Common uses for short length rebar are: forming stakes, garden stakes, tent stakes, sprinkler head stakes, connector ties, concrete projects. Rebar is made of unfinished steel and is susceptible to rusting; surface rust will not affect the performance of rebar.