Durable Restoration of Reinforced Concrete Grillage Roof Shell of Ensor Gallery in Ostend (B)

The roof of the Ensor-gallery at Ostend is a cylindrical vault, constructed as a coarse grillage of reinforced concrete, with embedded reinforced concrete roof panels with prismatic glass tiles. The concrete ribs of the roof shell were heavily damaged by long term exposure to the chloride containing sea air, causing severe reinforcement corrosion. The paper presents the experimental data on the degradation, as well as the alternative approach used in the restoration project to avoid the loss of a major part of the authentic material. The approach is based on a combination of galvanic cathodic protection with embedded and bored in sacrificing anodes, the application of a chloride-inhibiting impregnation followed by a re-alkalizing treatment on the preserved parts, concrete repair and reconstruction with a self-compacting, shrinkage-compensating, polymer-modified repair mortar. Completely denuded steel reinforcement bars were replaced by glass fiber reinforced polyester rods.