Investigation of the Deterioration of Medium-Rise-Wall Type Reinforced Concrete Buildings with External Insulation in Snowy Cold Districts

Abstract

We have clarified that external insulation reduces the probability of reinforcement corrosion in reinforced concrete buildings in cold snowy districts by 45–78%. Renovation of external insulation is one of the effective methods for improving the insulation performance and durability of reinforced concrete buildings, but there are almost no data that demonstrate durability. Therefore, the carbonation depth and the cover depth were investigated for six medium-rise-wall type reinforced concrete buildings in Hokkaido, Japan, which had been refurbished for external insulation. As a result, it was clarified that the external insulation suppressed the carbonation depth by 30% or more, even when the bonding method of the external insulation was different. In addition, it was clarified that the external insulation further suppressed carbonation in walls where the carbonation depth tended to increase in snowy cold districts. Specifically, external insulation reduced carbonation by up to 35% on surfaces that tend to dry out due to sunlight, and by 49% on surfaces that are affected by water that deteriorates the concrete surface layer.