Concrete Repair
Concrete repair still remains the core activity of our business. Reinforced concrete is a very durable construction material but it needs to be maintained like most other products if it is to achieve its design life. Apart from physical damage to the concrete the main reason for deterioration is corrosion of the reinforcement, the most common cause within the UK being carbonation the other chlorides. One mechanism by which the passive surface conditions of reinforcing steel can be disrupted, and serious corrosion damage can set in, is known as carbonation. Through the ingress of carbon dioxide from the external atmosphere and its reaction with the pore solution, the pH of the pore solution tends to decrease (become more acidic). A decrease in internal pH levels to around 8 has been reported. The carbonation "front" gradually penetrating into concrete can be revealed on cross sections treated with an indicator solution. When this "front" reaches the embedded reinforcing steel, it is clearly more vulnerable to corrosion damage. Relatively porous concrete, wet/dry exposure cycles, low concrete cover and relatively high levels of carbon dioxide have been associated with an increased corrosion risk. A more complex reinforcing steel corrosion mechanism is chloride-induced attack. Harmful chloride species can originate from the original mix ingredients or from the external environment, notable de-icing salts applied in cold climates and marine exposures. Once conditions conducive to corrosion damage on the reinforcing steel surface have been established, the formation of voluminous corrosion products will generate tensile stresses in the concrete and subsequent spalling on the concrete cover. Extensive cracking in, and loss of, the protective cover obviously leave the reinforcing steel particularly vulnerable to further corrosion damage from the external environment. Through inspection, testing and analysis we at Churchill refurbishment Ltd look to formulate long term cost effective repair solutions based on a structural design life obtained from you the client. We are approved applicators of the Fosroc, Sika and Flexcrete concrete repair systems and often work with our material suppliers to offer back to back warranties on materials and workmanship.