Concrete admixture from University of Colorado, Boulder uses a polymer that inhibits ice formation to increase the concrete's freeze‑thaw resilience.

Benefits

  • Frost‑resistant
  • Resilient

Applications

  • Bridge design
  • Building design
  • Construction

UN Sustainable Development Goals Addressed

  • Goal 9: Industry Innovation & Infrastructure

  • Goal 11: Sustainable Cities & Communities

The Challenge

Concrete is one of the most common building materials, yet is vulnerable to damage from environmental exposure. In regions that have large temperature swings, concrete roads and buildings go through ‘freeze-thaw cycles’, where the water freezes and expands inside the concrete, forming ice crystals that create enough pressure to create cracks and cause damage. To mitigate against the damage caused by freeze-thaw cycles, engineers add air-entraining admixtures, which add microscopic bubbles to the mixture to help prevent freezing. However, the bubbles lower the strength of the material and make it more porous, making it more likely that water and salt will get in. If water enters the concrete and the temperature drops to freezing, ice can form, and the structure can crumble and spall.

Innovation Details

The concrete admixture contains polymer molecules with anti-freezing abilities. The researchers mimicked anti-freeze proteins found inside the cells of certain organisms. The proteins bind to ice crystals and prevent them from growing. The bio-inspired polymers were able to effectively reduce the size of ice crystals by 90%. A concrete mix containing the polymer was able to withstand 300 freeze-thaw cycles without losing its initial strength.