Due to increased development in the area, the existing Pentz Street Sewage Pumping Station in Wellington, Western Cape was finding it difficult to cope. In 2011 the Drakenstein Municipality determined to construct a new pump station.

Lyners Consulting Engineers were contracted to design the pump station and Exeo Khokela was awarded the construction contract. Sika was elected to supply their universal waterproofing products and joint sealants. However, a decision was pending on which supplier would be providing the vitally important chemical resistant products required for the project. Once the advantages of using two outstanding products in the Sikagard range were recognised, Sika won the contract, thereby increasing their input on the project from 340m2 to 1650m2, or from 20% to 100% of the surface areas.

Contractors commenced phase one of the project in November 2011. To ensure no leaks would occur between the various concrete segments, SikaSwell-P Profiles and SikaSwell S-2 were applied in the construction joints of each segment. Both products swell in contact with water, are highly economical, easy to apply on a variety of different substrates, and adaptable of fitting many different detailing tasks. SikaSwell-P Profiles are preformed and requires no hardening time, no welding and is available in various types and dimensions. SikaSwell S-2 is a one-part polyurethane sealant with an optimized expansion rate that prevents damage to fresh concrete during curing. It is permanently water resistant and is used as bedding adhesive for the SikaSwell Profile.

Sika Cemflex (300 litres), an acrylic based emulsion, combined with cement to produce a waterproofing agent, was applied to the structure externally.  Mixed with Portland cement and water, Cemflex forms effective waterproofing slurry that is watertight, non-toxic and UV stable. To initiate chemical protection of the internal walls of the pump station, Sikagard-720 EpoCem ZA (440 kits) was applied as a Temporary Moisture Barrier (TMB). Providing easy and fast application, this three-part, epoxy-modified, cementitious, fine-textured mortar, is applied under epoxy or polyurethane resins, over high moisture content substrates, even green concrete. It requires minimum waiting time prior to application of other Sika resin-based finish products. Sikagard-720 EpoCem ZA may also be used as a leveling mortar, a pore sealer and in food processing plants. Sikagard-63 N (155 kits), a solvent-free, two-part, epoxy resin coating was subsequently applied as the second layer of chemical protection to the inside of the pump station. This abrasion-resistant universal coating material is designed for normal to highly aggressive chemical environments, is easy to apply, liquid proof and provides excellent chemical and mechanical resistance.

In some areas of the construction, the casting of concrete had not gone according to plan, resulting in additional Sika products being specified for repair work. Sikadur-32 N, a solvent-free, moisture insensitive, structural epoxy bonding agent, was used to bond steel anchors into the defective concrete prior to application of fresh concrete. Its tensile strength is far greater than that of concrete and it can be applied to damp substrates.

A second dowelling epoxy used for these repairs was Sikadur-31 CF Normal, a moisture tolerant, thixotropic, structural adhesive based on a combination of epoxy resins and special fillers. It may be used as an adhesive and repair mortar on numerous surfaces, as well as for joint filling and crack sealing. It hardens without shrinkage, is impermeable to liquids and provides good chemical resistance. Both these Sikadur products are easy to mix and apply and provide excellent adhesion.

To bond new concrete to old (wet to dry) SikaTop-Armatec 110 EpoCem was used. This cement-based, epoxy-modified, three-component bonding agent may also be used as an anti-corrosion coating for reinforcing steel. It provides excellent adhesion with a high degree of mechanical strength. These areas were then patched with Sika Rep LW, a one-component, non-sag, cement-based repair mortar that is easy to mix, apply and finish and which provides a compatible surface for the application of Sika’s coating products. Suitable for exterior, interior, vertical or overhead surfaces, this multi-purpose mortar is shrinkage compensated, permeable to water vapour and provides excellent adhesion.

The first phase of this project took approximately 11 months to complete, with delays, caused by bad weather conditions, twice resulting in flooding of the site. The second phase is scheduled to take three months to complete, during which time further high performance Sika products will be used. The new Pentz Street Pump Station has been designed to accommodate existing and future flow from industrial and residential developments and is expected to service the Wellington area for the next 25 years. Just another example of Sika’s ability to prove the sheer quality and efficacy of its products.