Weak Points and Failures of Concrete Bridges in Cold Regions : A Literature Review

In cold regions, de-icing salts are commonly applied to roads and bridge decks during winter to prevent icing and facilitate traffic flow. However, the use of de-icing salts can damage the concrete surface and cause reinforcement corrosion. Additionally, bridges in cold regions are affected by freeze-thaw cycles, which can lead to scaling on the concrete surface and internal damage, such as Durability (D-) cracking. Reinforcement corrosion and freeze-thaw damage are the most common causes of concrete failure in bridge structures in cold regions. Concrete bridges in cold regions are also susceptible to alkali-silica reaction (ASR), a chemical reaction between the alkaline pore solution in concrete and silica in aggregates. ASR causes expansion, map cracking on the concrete surface and degrades the mechanical properties of the concrete. Scour is identified as the primarily cause of bridge failures in many regions, according to previous studies, and scour damage often worsens during flooding. Ice floes are identified as the third most common cause of hydraulic bridge failures. Their heavy weight and high velocity can damage various bridge components. These failure mechanisms can lead to severe damage, cause bridges to fail, significantly reduce the service life of the bridge, or, in the worst case, result in collapse. The objective of this master thesis is to study these weak points and failures in concrete bridges in cold regions and identify preventive measures to improve the durability and extend the service life of concrete bridges in future bridge designs. The aim is to increase knowledge and understanding of concrete bridge failures in cold regions to prevent and minimize these bridge failures in the future. The study is based on a literature review in which the causes of bridge failures are identified, and preventive measures for each failure are analysed and described, primarily based on design codes. Case studies of bridge failures are presented and discussed. The impacts of climate change on theses failure mechanisms are also discussed, resulting in accelerated deterioration of concrete structures due to changes in atmospheric CO2 concentration, temperature and relative humidity.