Concrete technology
Upon request, we compile a complete recipe for our projects, taking into account the type and quantity of the planned fibers.
The addition of fibers to concrete can be done in a precast plant, at a concrete mixing plant, and in special cases, dosed on-site. Basically, the recipe does not change with the addition of fibers. It is essential to adhere to the rules and standards for making quality concrete. However, there may be differences in their behavior in the concrete depending on the fiber type.
Regarding the application, it is good to know about these to avoid surprises for the contractor. Below, we will write about these in detail, but we are also available to our partners by phone and in person if needed. In the case of larger volume work, we also prepare concrete technology guidelines specifically for the project.
A common question is when, where, and how to mix in the fibers. The method of mixing is fundamentally influenced by the wetting ability of the fiber surface. We need to distinguish between fibers that can be wetted based on their inherent properties (e.g., glass fibers like Aveeglass products or polyacrylonitrile fibers like Avekril products) and hydrophobic surface fibers that can be wetted due to surface treatment (mostly polypropylene like Multi).
Let's start with the latter, Multi, as it is simpler. For this type of fiber, it almost doesn't matter at which stage of raw concrete mixing we add it. However, it is safer to treat them as members of the first group, as described below.
The Avekril Conti, Aveeglass Optimo, and Aveeglass Hybrid differ significantly from other similar-purpose synthetic fibers developed for concrete. Therefore, it is important to review the professional use of these fibers with excellent parameters.
For example, Avekril Conti is made of polyacrylonitrile, a wettable fiber, unlike polypropylene fibers. The surface of Avekril Conti fibers is pre-wetted for quick mixing in concrete, anti-static properties, and efficient post-treatment.
Aveeglass glass fiber products behave similarly when exposed to water. Glass surfaces also like and strongly bond with water. Just think of trying to separate two glass plates with water between them.
However, this excellent property of Avekril and Aveeglass products for their intended use can turn negative if not mixed properly. If these fibers come into direct contact with water during mixing, they will try to absorb it. The water film formed between the fibers binds them together with such force that it is unlikely to mix them lump-free during further mixing of the raw concrete. Under unfavorable conditions, especially with water, Avekril Conti can clump together like a "mop." The effect is similar to the water film between two glass plates; if we try to separate them, the water film will be stronger.
The mixing of High Grade, High Grade Eco, Standard, and Standart Plus fibers in a mixing plant does not prolong the mixing cycle. The specified mixing time for each concrete recipe must be followed. However, special mixes of concrete products may require longer mixing times. Fibrillated fibers can be added directly to the mixing drum of the concrete mixer truck. It is important that this is done layer by layer in the mixing plant. We recommend breaking the packaging before adding.
If, during the application, we observe uneven mixing or the fibers do not open up, the concrete must be mixed at the highest speed in the mixer to achieve even distribution. Fibrillated fibers can be worked into any concrete mix. The fibers reduce the consistency of fresh concrete. The desired consistency must be adjusted with a plasticizer!
Adding more water than specified in the recipe is PROHIBITED!
Adding Concrix macro fibers results in a decrease in the concrete's slump value, so it may need to be corrected with the addition of a plasticizer or by selecting another slump class. Adding more water than specified in the recipe is prohibited. The concrete mix design - particle structure, cement content, water addition, water/cement ratio, and the addition of concrete additives - can be used in its original form. Concrix fibers are neutral to concrete additives and are alkali-resistant.
The amount of fiber added can vary depending on the structural load requirements. For macro fibers, the correct dosage is typically 3-4 kg/m³.
Based on experience, we recommend adding the fibers in the mixing plant (either directly into the plant mixer or into the mixer truck drum at the plant), ensuring that the fibers are mixed homogeneously without clumping, resulting in well-mixed concrete that can be easily handled and worked on-site. Mixing Concrix macro fibers in the mixing plant does not prolong the mixing cycle. The specified mixing time for each concrete recipe must be followed. However, special mixes of concrete products may require longer mixing times. Concrix fibers can also be added directly to the mixing drum of the concrete mixer truck.
