Concrete seems like it can last forever. There is a good reason for thinking that because concrete construction has been around since about 1200-1400 B.C. The Romans used it in their construction projects and many of their structures, such as the concrete dome of the Pantheon in Rome still exists today. It remains one of the most durable manufactured building materials used around the world. To get rid of it requires concrete saws, demolition hammers, concrete crushers, mounted breakers, and even explosives.

Though extremely hard and dense, concrete can suffer damage. Chemicals, weather, impacts, thermal stress, insufficient reinforcement, and even age can take a toll on concrete. The good news is concrete rehabilitation can often repair the damage.

Blackwell’s, Inc. contracted to rehabilitate concrete structural beams

We recently did work to rehabilitate the concrete structural beams and concrete ceiling in a unique and historic grist mill built in the 1820s. The mill was in use for over 100 years grinding corn and wheat, while at the same time generating hydro-electric power.

Close examination of these photos of the concrete ceiling of the mill reveals the imprint of the wooden forms used to cast the concrete during construction of the mill. The photos also show the corrosion of the exposed rebar reinforcement and the spalling of the concrete on the ceiling and the structural beams.

These are the steps in the concrete rehabilitation

1. The ceiling was “sounded” to check for hollows and cavities in the concrete ceiling and structural beams
2. Spalled and delaminated concrete, as well as old pieces of the wooden forms were removed
3. Vapor blasting removed oxidation and rust on the exposed reinforcement rebars
4. The entire ceiling was vapor blasted to remove limescale and to profile the ceiling and beams for the eventual application of a repair mortar
5. A repair mortar made of a cementitious material, a binding polymer, and a corrosion inhibitor rehabilitated the beams and ceiling
6. The beams and ceiling were pressure washed in preparation for a waterproof coating material
7. A concrete waterproof coating was applied to the ceiling, the structural beams, and the upper three feet section of the vertical wall

The concrete rehabilitation project was completed.over