Making history once again, Sika’s products and systems were top-choice in the construction of South Africa’s first ever Open Cycle Gas Turbine (OCGT) power station in the industrial outskirts of Atlantis, Western Cape. Situated on what once was sand dunes, the mammoth project was completed in two phases spanning four and a half years.

The significance of this new power plant cannot be underestimated. Eskom proposed the construction of the OCGT as a back-up power supply to relieve the pressure of South Africa's growing demand for electricity. Because constructing this power station was no small feat, it was of vital importance that the very best construction materials and solutions were used and Sika was very willing to provide the requisite expertise. Fiast, a German-based company, and one of the contractors recruited as part of the team for this R4 Billion project, designed and supplied all the mechanical units on site. While Fiast was responsible for the installation of these units in the Phase I, Phase II saw contractors Siemens (electrical experts) and Lesedi (steelwork) jointly taking charge. Roshcon Civil Engineering was also a valued player in this project, especially since the company holds the unofficial world-record for having completed Phase I and Phase II the fastest.

Together these contractors specified the use of Sika's high performance products, namely; SikaGrout-212, Sikadur-Combiflex, Sikadur-31 CF Normal, SikaTop Armatec 110 EpoCem, Sika MonoTop-612 and Sika MonoTop-615 HB. The project required extensive concrete repairs due to bad weather conditions and local unskilled labour, as well as comprehensive product training for all those working on-site. Additionally, the OCGT diesel tanks required the construction of concrete containment tanks in case of possible leakage.

The structural grouting required on site had to be of a high quality and Sika’s expansive cementitious grout, SikaGrout-212, fit the description perfectly. 3,000 bags of this non-corrosive, easy-to-use powder were mixed with water and used, under machine bases and between base and plinth plates, for its load-bearing capability. SikaGrout-212 offers an adjustable consistency, very good flow characteristics, rapid strength development and high final strengths. The Sikadur Combiflex Joint Sealing System, which consists of flexible Hypalon waterproofing tape and a suitable Sikadur epoxy adhesive (in this case Skadur-31 CF Normal), was used to seal all wall and floor joints in the concrete diesel containment tanks. Since the contracts for this project required the use of local labour, extensive training on the correct implementation of this system was conducted.

Approximately 5,000 linear metres of Sikadur-Combiflex ‘bandage’ (200mm x 2mm) for sealing high movement and irregular joints, was used together with 5500 litres of Sikadur-31 CF Normal, a two-part thixotropic epoxy resin adhesive. When fixed to a joint, this system allows irregular movement in more than one direction, whilst maintaining a high quality seal which is impervious to liquids and of definitive mechanical strength.

General concrete repairs were possible thanks to 300 kits of three-part SikaTop Armatec 110 EpoCem, a cement-based, epoxy-modified, anti-corrosion coating and bonding agent. This product has excellent adhesion to steel and concrete, contains corrosion inhibitors, and serves as an effective barrier against penetration of water and chlorides. Designed as a high strength repair and reprofiling system for concrete substrates, Sika MonoTop-612, is a cementitious, polymer modified, low permeability, high strength mortar containing silica fume and synthetic fibre reinforcement. The concrete surfaces on site received this repair mortar treatment in order to ensure that the structure would remain steadfast for years to come.

The final Sika product used on the OCGT project was Sika MonoTop-615 HB. Sika MonoTop-615 HB was developed to be used as a high build cementitious, polymer modified, one component repair and reprofiling mortar containing silica fume. 750 Bags were used to repair small defects on edges and joint sides, to form and finish joints and coverings.

The OCGT turbines project was successfully completed on schedule, despite challenges presented by unskilled labour and environmental conditions. Sika has once again proved its standing of one of the leading pioneers in the South African construction industry. Not surprising, considering 2010 marks Sika's 21st anniversary of trade in South Africa and a centenary of international trade.