Predicted corrosion rate on outdoor exposed concrete structures

Abstract

PurposeA significant part of Finnish concrete building stock is relatively young. Thus methods to adopt the existing building stock to climate change are needed. To plan and correctly timing the service actions there is a need to study the rates of different deterioration mechanisms. The reinforcement corrosion in Finnish outdoor exposed concrete structures is almost solely carbonation-induced corrosion. In former studies, it has been shown that active corrosion phase can also have a major effect on the total service life of the structure. The paper aims to discuss these issues.Design/methodology/approachIn this study, the effect of climate change on predicted corrosion rate of concrete reinforcement in projected 2050 and 2100 climates compared to present climate were studied to consider adaptation methods for the climate change. The calculations are based on a corrosion propagation model, which takes into account four different climatic factors: wind-driven rain, temperature, relative humidity and solar radiation.FindingsA significantly higher corrosion rates and thus faster corrosion-induced damage can be expected in the future climate. The increase in corrosion rate is the highest in the late autumn and winter because of the increasing amount of precipitation and weaker conditions for concrete structures to dry. In addition, the duration of high corrosion rate periods is increasing which may shorten the propagation phase. However, corrosion rate is highly dependent on the direction of the greatest climate load and the grade of sheltering which can be taken into account in service life calculations and while planning service actions.Research limitations/implicationsThere are different sources of error because of the uncertainties with both the used model and the climate change scenarios. That is why the results are discussed in more general way than comparing the actual numbers with each other.Originality/valueThe propagation model used in this study has not been used before in adaptation studies. The climate change effect on carbonation-induced corrosion has also been limited while the studies have focused on chloride-induced corrosion.