Construction World June 2016

MAITLAND RIVER MOUTH PIPELINE Last year Port Elizabeth’s Nelson Mandela Bay Municipality determined that after more than 20 years without maintenance, the city’s main water pipeline at Maitland River Mouth was in need of refurbishment. Engineers from Aurecon turned to Sika to supply its highly durable

products for waterproofing and protection of the pipeline itself, as well as repairs to the concrete base structures supporting the pipeline.

Forming part of Sika’s Concrete Repair and Protection System, Sika FerroGard-903+ and Sika MonoTop-610 were specified by Sika’s John Zehmke.“Corrosion protection provided by these products increases the service life and reduces the maintenance life cycle of reinforced concrete. SP Excel Plant & Civil were contracted to apply the numerous Sika products,” said Zehmke. As a Migratory Corrosion Inhibitor (MCI), Sika FerroGard-903+ was spray applied onto the concrete to form a protective monomolecular layer on the surface of the reinforcing steel. This passivation of the steel delays the onset of chloride-induced corrosion and reduces the rate of corrosion. Based on organic compounds, Sika Ferrogard-903+ does not alter the water vapour diffusion of concrete, prevents development of >

gas generation whilst still in the plastic state of curing, resisting the tendency of grouts to shrink away from restraining surfaces during the setting phase. Remaining cracks in the concrete were injected with Sikadur-52 ZA, a two-part, solvent- free, low viscosity injection liquid, based on high strength epoxy resins. It not only forms an effective barrier against water infiltration and corrosion promoting media, but also structurally bonds concrete sections together. “All of these high performance Sika products used enable easy mixing and application. Upon completion of this yearlong project, 432 m 2 of concrete were completely rehabilitated thereby significantly increasing the expected lifespan of this vital pipeline,“ concluded Zehmke.

incipient anodes and its easy applicationmakes it suitable for use where other repair or prevention options are not affordable. Sika MonoTop-610, a cementitious, polymer modified, one-component, bonding slurry and primer with active corrosion inhibitors, was used for protection of the reinforcing steel. It provides excellent adhesion and good resistance to water and chloride penetration. For repairs on the deteriorated concrete, Sika Rep, a one component, cement-based multi-purpose patching and repair mortar was used. It is shrinkage compensated, vapour permeable and provides excellent adhesion. SikaGrout-212, a high performance, non-cor- rosive, cementitious grout was used for repairing concrete. Easy to mix with an adjustable consistency, it provides rapid strength devel- opment and high final strengths. It expands by

31

CONSTRUCTION WORLD JUNE 2016