Concrete has been used in the UK as a primary construction material for many years. Although an extremely versatile material, concrete does require maintenance in order to extend the life of many structures.
Concrete can be damaged by various processes, such as the expansion of corroding reinforcement, freezing of trapped water, fire or radiant heat, aggregate expansion, sea water effects, bacterial corrosion, leaching, erosion by fast-flowing water, physical damage and chemical damage from carbonation, chlorides, sulfates and acids.
The most common cause of concrete deterioration is Carbonation. Carbonation is the reaction of carbon dioxide in the environment with the calcium hydroxide in the cement paste. This reaction produces calcium carbonate and lowers the pH to around 9. At this value the protective oxide layer surrounding the reinforcing steel breaks down and corrosion becomes possible. The reaction of carbon dioxide and calcium hydroxide only occurs in solution and so in very dry concrete carbonation will be slow. In saturated concrete the moisture presents a barrier to the penetration of carbon dioxide and again carbonation will be slow. The most favourable condition for the carbonation reaction is when there is sufficient moisture for the reaction but not enough to act as a barrier. In most structures made with good quality concrete, carbonation will take several (or many) years to reach the level of the reinforcement.
Churchill carry out concrete repairs to all types of concrete structures such as; bridges, buildings, water towers, bund tanks and Silos.