Switzerland-based waterproofing, protecting and reinforcing products supplier Sika provided the range of products used in the refurbishment of the Nelson Mandela Bay metropolitan municipality’s main city water pipeline at the Maitland river mouth, in the Eastern Cape.

The pipeline, which has not undergone maintenance for several years, underwent a major refurbishment that started in March 2014 and was completed in June 2015.

Concrete repair and protection products used in the Maitland River Mouth pipeline refurbishment project included the Sika MonoTop-610 primer and the Sika FerroGard-903+ corrosion inhibitor, besides others. These products increase the service life and reduce the maintenance life cycle of reinforced concrete, owing to the corrosion protection they provide, says Sika construction area sales manager John Zehmke.

Sika FerroGard-903+ is a migratory corrosion inhibitor, which was sprayed on the concrete surface of the water pipeline to form a protective monomolecular layer on the surface of the reinforcing steel.

“This passivation of the steel assists in delaying the onset of chloride-induced corrosion and reduces the overall rate of corrosion”, Zehmke tells Engineering News.

The inhibitor is based on organic compounds, such as amino alcohols and organic and inorganic inhibitors, and it does not alter the water vapour diffusion of concrete. It also prevents the development of incipient anodes and the easy application process makes it suitable for repair and prevention of corrosion cells.

Sika MonoTop-610 is a cementitious, polymer-modified, one-part component bonding slurry and primer with active corrosion inhibitors used for the protection of the reinforcing steel. It provides adhesion and good resistance to water and chloride penetration.

“These high-performance Sika products used on the refurbishment project enabled easy mixing and application. Upon completion of this year-long project, 432 m2 of concrete was completely rehabilitated, thereby significantly increasing the expected life span of this vital pipeline,” adds Zehmke.

Other products used in the Maitland River Mouth pipeline included SikaGrout-212, a high-performance, noncorrosive, cementitious grout used to repair concrete. It has a special blend of shrinkage-reducing and plasticising/water-reducing agents, and compensates for shrinkage in both the plastic and hardened states. As a structural grout, it provides the advantage of multiple fluidity with a single component.

Sikadur-52 ZA – a two-part solvent-free and low-viscosity injection liquid based on high-strength epoxy resins – was used to rehabilitate the remaining cracks in the concrete.

More about Sika

Sika is a global speciality chemicals company, with its South African head office in Durban and branches throughout the provinces, including Gauteng, theEastern Cape and the Free State.

Headquartered in Baar, Switzerland, it supplies the building, construction and manufacturing industries with materials used in the sealing, bonding, damping, reinforcing and protection of load-bearing structures.