The Clearwater Corporate Office Park project in Gauteng’s East Rand is one of the largest office buildings to use hollow core floor slabs in South Africa. The use of polypropylene fibres in the concrete flooring applications provided major benefits for the client, contractors and various stakeholders who were involved in the project.

Concrete and cement admixture specialist CHRYSO Southern Africa supplied Chryso Durus S400 Macro Fibre for the project. The fibres are an integral component of the screed that was placed on top of hollow core slabs, which are located on all three above ground storeys of the structure. Each hollow core slab received a concrete topping, the bottom and middle floors having a 50mm thick concrete topping, while the third – the roof – received a thicker topping of 75mm.

Because of its association with UK-based Adfil Construction Fibres and Oxifibre, CHRYSO Southern Africa was able to offer a unique fibre solution that enhances the durability of the screed by combining the strength of concrete with the flexibility of the polypropylene fibre product. It also minimises surface cracking in the concrete.

Electrical, plumbing and data services are housed in the conduits, which are normally located below steel mesh that is traditionally used to prevent plastic shrinkage cracking in the screed. John Swart from the contracting firm on the project, Ludikon, says that one of the major challenges on this project was insufficient space to use conventional steel reinforcement, because of the large volume of service conduits that had to be installed within the topping.

“We therefore used a fibre solution that resulted in significant time savings on the project too,” commented John. Other benefits of the fibres included impact resistance and the ability to facilitate a multi-directional plastic shrinkage cracking reduction matrix.

For more information, contact Chryso on +27 (11) 395 9700 or via