Abstract
This study presents a novel method to assess the freeze-thaw exposure of concrete structures. The new Relative Freeze-Thaw Exposure index (RFE) is based on regression model that considers location-related actual freeze-thaw damage observations, number of freeze-thaw cycles and both annual and cycle-related amount of wind-driven rain (WDR) before cycles. The RFE index is then used to compare location-, direction- and climate-related freeze-thaw exposure levels.
It can be concluded that the amount of WDR before each cycle has the most significant effect on freeze-thaw damage. Freeze-thaw exposure level is highest in present climate and remains the highest in Finland’s coastal area regardless of the used climate change scenario. In Finland’s coastal area and southern Finland, the exposure level increases more from eastern and western directions than southern which indicates that the exposure level is getting more evenly distributed. However, the southern direction remains with the most severe exposure in almost every studied case in every location.
Freeze-thaw exposure for outdoor concrete structures is not getting less severe with the changing climate in Finland. The quality of concrete (e.g. success of air-entrainment) and protecting concrete from free water remain the main methods against the initiation of freeze-thaw damage.