Sika’s Macro and Micro Fibres came to the fore recently when concrete slabs were laid in Tzaneen, Limpopo Province for a large chicken breeding company. In terms of European Union regulations, cracking of flooring where livestock is housed must be completely eliminated to prevent bacterial growth, which can cause contamination of the stock.

The cost of disease on poultry farms results in low production performance meaning fewer eggs, less meat, slow growth rate, and poor product quality. Three elements of biosecurity help to reduce such infections - segregation and traffic control, cleaning, and disinfection. When all dirt is removed, little organic material is left for disease agents to thrive in. Eliminating cracking in the floor slabs will reduce the spaces in which bacteria breed and therefore concrete floors are highly recommended, as they are easy to clean. Due to very high on-site temperatures during this project, the occurrence of shrinkage cracking in the fresh concrete was highly likely, but the problem was solved when Sika assured the client and the contractor, Echo Coldrooms, that their Macro and Micro Fibres were the ideal solution.

As an alternative to welded mesh reinforcing, Sika Fibres F-Macro X 40/0.8 was mixed with the concrete prior to placement of the slabs. Consisting of structural synthetic polypropylene macro fibres with an X-shaped cross sectional surface area – 40mm in length x 0.8mm in diameter, this highly effective product provides excellent bonding while increasing the load bearing and energy absorption capacity of concrete. Sika Fibres F-Macro X 40/0.8 is corrosion resistant, increases the flexural strength, while its high impact and abrasion resistance increases the durability of concrete. This homogenous reinforcement is ideally suited for use in mining, tunneling, slope stabilization, pipes and culverts, blast resistant structures, safes, cellars as well as pavements and road overlays.

Due to the mechanical properties of Sika Fibres F-Macro X 40/0.8, Echo Coldrooms was able to enlarge the saw cuts and construction joints in the floors. This allows for more movement between the slabs, which reduces tension in the concrete slabs and further minimizes threats of cracking.

As an additional reinforcement and specifically for control of early plastic shrinkage and settlement cracking, Sika Micro Fibres was added to the concrete. This product consists of 12mm long Fibsol polypropylene micro fibres that reduce the tendency for plastic and drying shrinkage-cracking. Improving durability, abrasion resistance and impact resistance in newly cast concrete, these fibres also reduce water migration and permeability. Sika Fibres are applicable to all types of mortars and concrete which demonstrate a tendency to cracking, such as façade render, precast products, as well as roads, pavements and concrete slabs and overlays.

Both Sika Macro and Micro Fibre products are safe and easy to use. Construction time reduced to an absolute minimum owing to their being pre-mixed with the concrete in the Ready Mix trucks, and by eliminating the placement of welded mesh.