In ground-supported ready-mixed concrete for warehouse floor slabs, external hardstandings, and commercial vehicle pavements, SikaFiber 6 PPF is introduced during central batching at a dosage of 0.6–0.9 kg/m³ to limit plastic shrinkage cracking in the interval between strike-off and final set. The addition rate is selected against the anticipated bleed rate, surface evaporation rate, and the dimensional restraint imposed by formwork or doweled joints; at this dosage the fibre population is sufficient to bridge capillary menisci without producing measurable loss in slump beyond 20–40 mm at water–cement ratios between 0.45 and 0.55. Compliance for civil and industrial floors procurement is normally verified through EN 14889-2:2006 third-party conformity certification, with North American specifications referencing ASTM C1116/C1116M Type III synthetic fibre-reinforced concrete; plastic shrinkage behaviour is compared by restrained slab methods such as ASTM C1579-21, while fresh concrete acceptance remains under EN 206:2013+A1:2016 or ASTM C94/C94M. In production, the fibre is dispensed either by automatic bag-opening units at the mixer charging hopper or by fibre-dosing systems interlocked with aggregate weigh belts; direct discharge into high-velocity augers without pre-wetting is avoided because monofilament fibre bundles may segregate in low-moisture aggregates. The batching sequence places coarse aggregate, sand, and fibre into a twin-shaft paddle mixer for dry mixing of 30–45 seconds before the addition of cement, water, and admixture; total mixing time is extended by 15–30 seconds relative to plain concrete to disperse the fibres. Delivery is normally by standard truck mixer at 3–6 rpm agitating speed, with no more than 300 revolutions before discharge to limit fibre balling at the hopper screen. Placement on site uses laser-guided screeding machinery followed by power trowelling; the fibre does not impair pan float finish when the trowel blade angle is advanced after bleed has ceased. Terminal finished products include jointed ground-bearing floor slabs in logistics warehouses, racking aisles with flatness tolerances checked under DIN 18202, external apron slabs, fuel-station forecourts, and rural hardstandings. The operational boundary is explicit: SikaFiber 6 PPF is not a substitute for structural steel reinforcement, dowel bars, or armoured joints, and it is not specified where post-crack residual flexural capacity is required under imposed load.

What Limits Early Demoulding of Dry-Cast Non-Structural Precast Concrete?

Polypropylene micro fibre dosing in dry-cast and zero-slump precast concrete is concentrated on edge preservation and green-strength demoulding rather than hardened structural toughness. For cable troughs, socketed pipes, manhole rings, concrete blocks, agricultural slatted floors, and retaining-wall segments, the addition rate is typically 0.6–1.2 kg/m³ of concrete; the upper bound is constrained by reduced compaction response in dry-cast mixes when fibre content rises above 1.5 kg/m³, at which point vibration energy transfer becomes non-uniform and mould corners may show porosity. Product compliance is evaluated under EN 13369:2008 common rules for precast concrete, specific product standards such as EN 1916:2002 for concrete pipes and EN 14889-2:2006 for polymer fibre conformity; North American precast drainage products may be tested under ASTM C76 or ASTM C1479 where applicable. The production process integrates the fibre at the pan mixer stage: aggregate and fibre are dry-blended for 30 seconds before cement and water are added, and the total cycle time is controlled because dry-cast mixes have moisture contents between 5% and 8% by mass. After mixing, the zero-slump concrete is transported to the casting station by skip hoist or conveyor; the concrete is placed into steel moulds and consolidated by high-frequency external vibration. Demoulding of pipe and manhole segments at green strength is possible only when the micro fibre suppresses crack initiation at sharp corners and handling stresses; published data for this specific dry-cast configuration is limited, so site trials are required to confirm the optimum dosage for the mould geometry. Surface finishes remain compatible with water-based concrete release agents, and fibre protrusion at formed surfaces is generally minimal at dosages below 1.0 kg/m³. The addition should not be used to replace conventional curing compounds in products exposed to rapid surface moisture loss during steam curing; the fibre acts during the plastic phase only. Terminal finished product types include non-pressure concrete pipes, stormwater culvert segments, cable troughs, interlocking paving blocks, masonry units, slatted flooring elements, and precast retaining-wall segments.

Wet-Mix Shotcrete Lining Pressures and Early-Age Crack Control in Underground Excavations

In wet-mix shotcrete for primary tunnel lining, SikaFiber 6 PPF is dosed into the truck mixer at the batching plant at 0.9 kg/m³ to 1.5 kg/m³, depending on the ground support class, early-age curing conditions, and accelerator chemistry. The fibre is dispersed before the air-entraining and water-reducing admixture package because late introduction into a pressurised wet-mix line can produce fibre agglomerates at the pump hopper. Spraying is performed with a positive-displacement concrete pump or pneumatically assisted wet-mix machine, at a nominal line pressure of 20–80 bar, with a nozzle distance between 0.6 m and 1.2 m from the substrate. The addition of a liquid alkali-free set accelerator at the nozzle at 3–8% by mass of cement is compatible with the micro fibre; the fibre does not contribute to rebound in the same way as rigid steel fibre, but rebound rates must still be controlled by mix cohesion and nozzle angle. The key process conflict is the interaction between the fine-fibre population and high-early-strength accelerator: at dosages above 1.8 kg/m³ the plastic viscosity may increase to the point where pump stroke efficiency drops and blockages occur in 50 mm delivery lines; for that reason the upper dosage is set at 1.5 kg/m³. Lining installation is carried out in layers of 50–100 mm per pass, with the fibre controlling plastic shrinkage in the exposed surface before the next pass. Terminal products are permanent and temporary shotcrete linings in road tunnels, metro stations, rock slope stabilisation, cut-and-cover retaining walls, and swimming pool shells where spray-applied concrete is used as the primary lining.

Verification of wet-mix shotcrete containing SikaFiber 6 PPF is performed against the following conformity checks.

The product is not a structural fibre and cannot replace steel fibre or welded wire mesh when the design specifies post-crack flexural energy absorption under EN 14488-3:2006 or ASTM C1609/C1609M. Pumping lines should be cleaned after each shift; fibre residue in reducing sections has been observed to accelerate blockages when mortar temperature exceeds 30 °C.

Cementitious self-levelling underlayments and bonded screeds produced with silo-mixed binders require early plastic-phase crack control when the installed layer thickness falls below 40 mm and when underfloor heating pipes create an irregular section. SikaFiber 6 PPF is incorporated at 0.6–1.0 kg/m³ of mixed screed to reduce plastic-phase crack development over heated floors, old concrete substrates, and variable-thickness sections between 20 mm and 50 mm. Compliance for screed materials is assessed under EN 13813:2002, which designates strength classes and wearing suitability, while flexural and adhesion testing follows EN 13892-2:2002; fibre conformity is certified separately under EN 14889-2:2006. In production, the fibre is pre-blended into the dry binder in a continuous silo mixer or added with the first water fraction in mobile mixing pumps. The mixed material is pumped through 25–50 mm internal-diameter hoses to the placement area, where it is spread with a gauge rake, smoothed with a smoothing trowel, and de-aerated with a spike roller before final levelling. The insertion of a fibre population during mixing raises plastic viscosity slightly, so the water demand at a given flow diameter may need to be adjusted within the manufacturer's maximum water–binder ratio; excessive additional water to restore flow may increase segregation and must be avoided. The fibre does not provide crack-bridging on moving joints, shrinkage joints, or structural cracks, and it does not reduce drying shrinkage once the matrix has hardened; therefore conventional drying-shrinkage control, substrate priming, and movement joints remain mandatory. Terminal finished product types include pump-applied self-smoothing underlayments under vinyl, LVT, and ceramic tile, bonded cementitious wearing screeds in renovation projects, floor levelling layers over underfloor heating systems, and cementitious separating layers where appropriate. In areas subject to moisture-sensitive floor covering, residual moisture limits from the adhesive manufacturer remain binding.

When PPF Is Introduced into Factory-Blended Dry Mortars and Concrete Repair Products

Factory-blended dry mortars and concrete repair products are corrected with SikaFiber 6 PPF at a target addition ratio of 0.6–1.2 kg/m³ of mixed mortar; the corresponding dry-batch weight is calculated from the mortar yield and must be fixed after laboratory trials. Compliance is anchored to EN 1504-3:2005 for structural repair mortars, EN 998-1:2016 for rendering and plastering mortars, and ASTM C928/C928M for packaged dry concrete repair sold in North America. The downstream production process is a batch dry-mixing operation: the fibre is first opened by a high-speed plow mixer to avoid balling before being blended with cement, graded silica sand, polymer binder, and powdered admixtures for a cycle time of 3–6 minutes. The critical process constraint is the moisture content of the dry blend; fibre addition into a mixer with residual moisture above 0.3% can lead to agglomeration at bagging screws and blocking of the packing spout. After blending, the material is discharged into valve bags or big bags, and the fibre is distributed homogeneously as a discrete phase. On the application site, the repair mortar is mixed with a prescribed water volume in a forced-action paddle mixer for 2–3 minutes, applied by trowel or spray, and finished with a float. The fibre contributes to plastic cracking resistance in patch edges and around embedded steel, but it is not a corrosion inhibitor and does not alter cathodic protection design; substrates still require mechanical preparation, and reinforcing steel must be primed or coated according to the repair specification. Terminal finished products include pre-bagged concrete repair mortars for spall repair, polymer-modified filling compounds, external rendered façade mortars, and dry-mix concrete for small non-structural castings. The material should not be used in acid-resistant or chemically aggressive overlays, and its effectiveness in fire-rated repair systems should be verified under EN 13501-1 before specification.