3 ms·

It only corrodes if it's not completely encased in concrete. The concrete stops the reaction. And, if one portion of the rebar is not encased it will eventually

• adolph 3mo ago
  This is something I wasn't aware of that is fascinating. The ph balance of the rebar's environment determines the progression of oxidation. There was a guy in the 1920's who observed this and had the idea to put cement in paint; it was so successful he renamed the company to cement spelled backwards. Inside the concrete, Ca(OH)₂, which is generated by the hydration of cement, creates a strongly alkaline environment, with a pH value of more than 12.7. In this environment, a passivation film forms on the surface of the rebar to prevent corrosion. However, the pH of the concrete decreases as micro-cracks develops and chloride from the outside infiltrates the rebar. Eventually, as the environment inside the concrete becomes neutralized, the corrosion of the rebar accelerates, which reduces the overall durability and stability of the reinforced concrete structure. https://www.sciencedirect.com/science/article/pii/S095006182503908X https://www.sciencedirect.com/science/article/pii/S095006182... A sighting of preserved steel reinforcing bars sticking out of old concrete rubble piqued the curiosity of our company founder, Albert C. Bean, Sr. After investigating this finding, his company, Armor Oil & Chemical Company, began producing a patented cement-filled coating formulation that, in its updated form, still protects structures from corrosion today. https://tnemec.com/about/ https://tnemec.com/about/