For the construction of the award-winning Gouda Wind Farm concrete towers, 100% locally produced Sika SA products were used.

The Gouda Wind Farm is the first in South Africa to be constructed primarily with locally produced concrete instead of imported steel towers, an innovation for which it received a Fulton Award from the Concrete Society of Southern Africa.

With the emphasis on local content, a range of Sika SA products was specified for the construction of the 46 towers, including Sikadur-31 CF (one ton per tower), Sealing Backing Cord (22km) and SikaGrout-295 ZA (30 tons per tower).

Standing 100m tall, each tower comprised of four precast concrete columns and a final segment carrying the nacelle. The horizontal joints on the tower segments were joined with Sika EVA Backing Strip. This semi-rigid, closed-cell, cross-linked construction foam is designed as a tough, flexible and resilient back-up support material for surface seals in load-bearing joints.

Once joined together, the vertical and horizontal joints were sealed with Sikadur-31 CF and Sikadur-31 DW. Both products are moisture-tolerant, thixotropic, structural two-part adhesives and repair mortars. Sealing Backing Cord was placed into the expansion joints to regulate the depth of seal and to provide a solid backing onto which the sealants were placed.

Mould imperfections were repaired with Sika MonoTop-620, a cementitious, polymer-modified, one-component pore sealer and levelling mortar containing silica fume.

The grouting of all vertical cavities was completed using SikaGrout-295 ZA, a one-component, ultra-high strength, cement-based grout, specifically designed for use in the renewable energy field, under metal bases, between concrete segments and to fill cracks, gaps and large voids. During the project, SikaGrout-295 ZA was sent for fatigue testing and certified for durability.

Sika
Tel: 031 792 5600
Website: www.sika.co.za

Caption: Each tower comprised of four precast concrete columns of 20m in height, which were joined, sealed and grouted together on site.