The first thing we have to be clear about is:

Micro fiber (fibers up to 20mm in length) and macro fiber (fibers from 21mm in length) do not compete with each other.
Each one has a totally different function in a concrete slab or screed.
The micro fiber cannot do the function of the macro fiber and the macro fiber cannot do the function of the micro fiber.
If we make a mistake in choosing the type of fiber in our project, our money will be totally wasted and the hearth will not get ANY BENEFIT.
If we make the wrong fiber, worse than the previous point, our screed will deteriorate because it lacks the fiber it needed.
The micro fiber is necessary in ALL Slabs / Slabs since it replaces the electrowelded mesh placed in the upper third of the slab. The microfiber works from the first minute of its addition, stitching the microcracks that occur in the concrete due to plastic shrinkage at the very moment of its appearance. In this way, it increases its density, decreases its porosity, decreases the penetration of air, water, carbonation and its capillary absorption, increasing the resistance to first flexural breakage. In short, it PREVENTS CRACKING due to excess loads and increases its useful life.
The macro fiber works after a crack has occurred due to overloading at the base of the slab. Thanks to its large size, it sews the cracks produced by an overload, preventing them from spreading and reaching the surface.

The micro fiber is always necessary, but the macro fiber is not it in 95% of the cases. (The macro fibers replace the lower mesh of a double mesh)

FIBRATEC offers its customers a range of fibers that are capable of responding in the most appropriate way to the needs of any pavement to replace the mesh. Our fibers have certain characteristics that, in any case, always exceed their competencies, both in final cost and in effectiveness and convenience. From the outset, they do not leave tips or hairs on the surface of the hearth, in addition to being the best performing in the world.

When a pavement is going to be designed, we must first calculate the stresses that will be generated in said pavement to determine what type of fiber to use. To do this, we will use Westergaard stress calculations. FIBRATEC has developed a online stress calculation that already incorporates the information resistance that our V12-AM micro fiber is capable of providing. In this way, anyone can calculate these stresses in just 15 seconds and determine if the hearth can be made with V12-AM (AR micro fiberglass) or else, they should opt for synthetic macro fibers and eventually some micro fibers. for microcracking.

As explained in our video , the Westergaard calculation shows us whether the loads to be exerted on the slab are large enough to cause an overload crack or not.

Traditionally, when the stresses resulting from the design were small compared to the stress that the concrete can withstand in flexion (in the case of a concrete of 25MPa (H25) around 3.3 MPa – 3.4 MPa), a shoe mesh (electrowelded mesh) in the upper third of the slab. This mesh does not serve to increase the resistance of the hearth as is often the common belief. Its task is to absorb the stresses of the plastic shrinkage of the concrete, ensuring that the existing micro-cracks in the concrete remain micro-cracks and do not become larger (it immobilizes the concrete of the upper layer of the slab).

Our 13mm FIBRATEC V12-AM microfiber made in Japan with the highest zirconium content in the world does that job infinitely better, providing a series of benefits as described above, that a shoe mesh cannot provide. ( See detailed information of V12-AM ) </ u>

If, on the contrary, the stresses that are going to be exerted on the floor of our project are higher than those that the concrete can withstand in flexion, we will know in advance that at the base of our floor (slab) cracks will form due to overloads. Traditionally this would lead us to place a double mesh (double electrowelded mesh). The lower mesh, placed at a distance between 3 and 5 cm from the base, would be in charge of holding the cracks that appeared at the base of the slab due to overload. This mesh placed in the lower third would prevent the propagation of these cracks towards the surface.

We recommend the addition of synthetic macro fibers to replace the mesh placed in the lower third of the double mesh. In particular, the Japanese two-component macro synthetic fiber BARCHIP MQ58 , which unlike others, will not leave any traces on the surface of the slab as long as it will have a quartz polished finish. Using V12-AM and MQ58 simultaneously is equivalent to placing a double mesh. (double mesh)

Our online calculation, by the way, also indicates the viability of the V12-AM microfiber screed to replace the mesh fitted in the upper third. It tells us how much point weight the screed can support depending on the dosage of the fiber, the condition of the terrain, the type of concrete selected, the thickness of the slab and the type of loads (racks, forklifts, car, truck …) .


  • SITUATION A: The screed is viable with V12-AM micro fiber
  • SITUATION B: The screed requires structural reinforcement with BARCHIP macro fibers in order to “provide residual resistance to stop the propagation of post cracks. break ”.

SITUATION A (Your screed can support loads only with the use of V12-AM in dosages ranging from 1 to 3 kg / m 3 ):

You compare the loads that your screed will have to bear, with the loads that our online calculation shows. If the online calculation indicates that the concrete fibred with V12-AM can