Final answer:
The last step in building a slab on grade is placing reinforcing steel after excavating, fine grading, and forming have been completed.
Step-by-step explanation:
Most people are familiar with reinforcing steel bars, commonly called “rebar”. It is used in bridges, buildings, skyscrapers, homes, warehouses, and foundations to increase the strength of a concrete structure. Rebar is used in concrete to provide additional strength, as concrete is weak in tension, while steel is strong in both tension and compression. Steel and concrete have similar coefficients of thermal expansion, so a concrete structural member reinforced with steel will experience minimal stress as the temperature changes.
When building a slab on grade, the last action that would typically be performed is placing reinforcing steel. The usual sequence of events starts with excavating, where the site is cleared and soil is removed to reach the desired grade. Next, fine grading occurs to ensure a level base and to prepare the soil to support the slab. Then, forming is done to create the edges and shapes of the slab, with wooden forms or other materials. Finally, reinforcing steel, often in the form of rebar or welded wire fabric, is placed to provide tensile strength to the concrete.