Which climate zone is described as severe climate with frequent freeze-thaw cycles and heavy salting?

• A. Zone I
• B. Zone II
• C. Zone III
• D. Zone IV

Answer: (C)

The key idea is that climate zones classify environments by how harsh they are for concrete, especially regarding freeze-thaw action and salt exposure. A severe climate with frequent freeze-thaw cycles means water inside the concrete repeatedly freezes and expands, which can cause cracking and surface damage if the mix isn’t designed to tolerate it. Adding heavy salting introduces chloride ions that accelerate corrosion of reinforcing steel and worsen deterioration at the surface. Among the zone classifications, this combination of strong frost action and substantial salt exposure is designated as Zone III, signaling a high level of durability concern without reaching the most extreme end of the scale. In Zone III, you’d expect emphasis on frost-resistant design, typically using air-entrained concrete and appropriate curing and protective measures to manage both freeze-thaw stress and salt exposure.