Efficient maintenance method for water supply facilities focused on the carbonation of concrete

摘要

In water supply facilities such as distribution reservoirs, the inner surface of reinforced concrete (RC) tanks isoften coated with resin paint or the concrete cover depth is increased to protect the concrete from surfacedeterioration. However, there is little published research on carbonation – one of the main causes of concretedeterioration – in relation to RC tanks, leaving room for improvement with regard to methods for preventing surfacedeterioration. This study discusses the impact of surface coating and environmental conditions on thecarbonation rate of concrete based on a survey of the present state of RC tanks of the Sapporo WaterworksBureau. Coating was found to have an inhibitory effect on carbonation. Because the carbonation rate of concreteused for the inside and outside of RC tanks was slow, the sufficient concrete cover depth to protect rebar fromcarbonation while in service was found to be 75 mm for RC tanks without coating.