Comparison
Macro fibre or steel mesh? Where they actually differ on site
Three-dimensional dispersion, corrosion, labour and programme. Macro fibre reinforcement versus steel mesh — measured against the pour, not the brochure.
Steel mesh has been the standard for ground slabs for decades. Macro synthetic fibre reinforcement claims to replace it. This piece sets the marketing aside and looks at where the two systems really part company on site.
Two dimensions versus three
Steel mesh is a plane. It sits at one height within the slab section and provides reinforcement only in that plane. Maintaining concrete cover, keeping the mesh from being pushed down during the pour, lapping the joints — all of that work exists to hold that plane in place.
Macro fibre disperses through the whole section. At 220,000 fibres per kilogram it works in every direction. You feel the difference exactly where mesh is weakest: edge and corner cracking.
Corrosion: a line item that disappears
With steel mesh, concrete cover is not a preference but a requirement, because the corrosion risk is real. In coastal structures, waste-water plants and humid cold stores that risk shapes the whole design.
Macro fibre is 100% polypropylene copolymer. Water absorption is zero and it is completely immune to corrosion. The concept of concrete cover disappears — and with it all the labour, checking and risk attached to that line.
Programme and labour
Laying mesh is skilled ironworking. Material has to reach site, be cut, laid, lapped and held in position through the pour.
Fibre is added to the concrete in the truck mixer. Application time typically drops by 50%. That is not only cost but programme: the next trade starts a day earlier.
Where fibre is not the answer
To be straight about it, fibre is not for everything. In structural elements requiring a static calculation — beams, columns, load-bearing walls — tensile reinforcement is still steel, and your project engineer's approval is essential. Fibre's territory is ground slabs, industrial yards, car park decks, sprayed concrete and precast elements.
Three questions to decide
- Is this element structural by calculation, or a slab on grade?
- Is corrosion or chemical exposure part of the calculation?
- How many days does the programme allocate to laying mesh?
On most industrial floor projects those three answers point at fibre. To be sure, send us the loads and the section — we will run the comparison for your project.
