CORROSION
Asset maintenance is a lifelong journey Routine maintenance of reinforced concrete structures is essential to extend their productive life. Ignoring the warning signs will significantly increase the cost of repair, and may pose a risk in extreme cases in terms of weakened structural integrity, says Wayne Smithers, manager: Technical Ser vices, Sika South Africa. By Alastair Currie
16
IMIESA July 2021
T
he first prize is to apply a protective coating on all new reinforced concrete structures – a widespread practice globally, but an uncommon one in South Africa. However, the added upfront cost has been proven to reduce the frequency and extent of future structural repairs and potential failures. “The most common causes of steel reinforcement corrosion are carbonation and chloride ingress. However, there are a host of other factors that include alkali-silicate reaction, chemicals, electrolysis, dampness and leakage, impurities in the water used to produce the concrete, and internal moisture – or combinations of these. Structural movement and overloading are
other contributing factors that can trigger corrosion,” explains Smithers. “That’s why it’s crucial to understand the root causes of corrosion before embarking on any repair solution.” As a specialty chemicals company, Sika is a market leader in the development and production of corrosion management systems and products. Some of the most widely used products include SikaTop Armatec-110 EpoCem. The latter is a cementitious, epoxy-resin-compensated, three-component coating material with corrosion inhibitor, used as a bonding primer, as well as for reinforcement corrosion protection. Another key product is Sika MonoTop-412 NFG – a one-component, polymer-modified, fibre-reinforced, low-shrinkage repair mortar with corrosion
