Protection against Chloride Ingress from De-icing Salts & Freeze/Thaw Cycling on Alpine Bridges
Background
Motorway bridges in this Alpine region are exposed every winter to sub-zero temperatures and heavy snow, needing liberal use of de-icing salts to keep them open.
Such salts, combined with frequent freeze-thaw cycling, impose a heavy burden on reinforced concrete structures and the bridges were starting to show signs of deterioration, which needed to be arrested.
The Solution
Cementitious Coating 851 was selected by the Highways Authority as the ultimate in protective coatings, not only waterproofing to provide resistance to cycles of freezing and thawing, but also forming an exceptional barrier to both chlorides and carbon dioxide. 851 is a proven defence against carbonation and has exceptional resistance to water penetration – amazingly 2mm coating offers equivalent water permeability to approximately 1 metre of structural quality concrete. It is capable of being applied at temperatures as low as 5oC, and it retains a degree of flexibility to take up the demands of thermal movement without cracking or loss of adhesion.
Client
Italian Highways Authority
Project Profile - Valle d'Aosta Bridges