| HS Code | 936188 |
| Material | 100% polypropylene |
| Fibertype | Monofilament |
| Form | Monofilament fibres |
| Colour | Natural |
| Fiberlength | 20 mm |
| Fiberdiameter | 0.032 mm |
| Aspectratio | 625 |
| Density | 0.91 g/cm³ |
| Tensilestrength | 350 MPa |
| Elasticmodulus | 3.5 GPa |
| Elongationatbreak | 20% |
| Meltingpoint | 160 °C |
| Ignitionpoint | 590 °C |
| Alkaliresistance | High |
| Waterabsorption | Nil |
| Recommendeddosage | 0.6–0.9 kg/m³ |
| Packaging | 1 kg bag |
| Shelflife | 24 months |
As an accredited SikaFiber PP Micro-20 - Monofilament Polypropylene Fiber for Concrete factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | SikaFiber PP Micro-20 is packaged in 0.6 kg water-soluble bags, with 20 bags per carton for concrete mixing. |
| Container Loading (20′ FCL) | 20′ FCL container loading of SikaFiber PP Micro-20: palletized bags of monofilament polypropylene fiber for concrete, securely stowed for export. |
| Shipping | SikaFiber PP Micro-20 is shipped as a non-hazardous, non-regulated solid in moisture-resistant bags or pails. Keep dry, away from ignition sources, and protect from UV. Use standard PPE and avoid dust. No special transport requirements apply; follow local, national, and international regulations. Store in a cool, dry, well-ventilated area. |
| Storage | Store SikaFiber PP Micro-20 indoors in a covered, dry warehouse, in a cool, well-ventilated area, away from direct sunlight, heat, sparks, flames, and strong oxidizers. Keep original bags sealed, stacked on pallets off the ground. Protect from moisture, contamination, and physical damage. Observe first-in, first-out rotation. Avoid prolonged UV exposure. No special ventilation required under normal storage conditions. Store at ambient temperature. |
| Shelf Life | Shelf life is 24 months from manufacture when stored dry, in original unopened packaging, protected from moisture and direct sunlight. |
High-strength precast segmental linings produced from C60/75 and C80/95 concrete exhibit a dense cementitious matrix with capillary porosity reduced by water/binder ratios between 0.28–0.35 and silica fume additions of 4–8% by mass of binder. Under the RWS fire curve, which raises the exposed surface to approximately 1200°C within 5 minutes and sustains that temperature for 120 minutes, near-surface pore water vaporizes faster than it can migrate through the disconnected pore structure. Vapor pressure rises to levels that exceed the tensile strength of the heated concrete cover, producing explosive spalling documented in full-scale tests at unprotected depths exceeding 100 mm. Monofilament polypropylene fibers with a nominal diameter of 20 µm and melt initiation at 160–165°C act as sacrificial pressure-relief pathways: the polymer melts and leaves continuous capillary channels approximately 20 µm in diameter through which vapor escapes before critical pore pressure accumulates. This mechanism does not increase the post-crack residual flexural strength of hardened concrete; that function requires macro fibres conforming to EN 14889-2:2006 Class II or steel reinforcement.
For fire-resistant segment production the addition rate is 2.0–3.0 kg/m³ of concrete. The lower bound applies to C60/75 mixes with a water/binder ratio at or above 0.30, while the upper bound is specified for C80/95 and above, where published furnace data report that 1.0 kg/m³ is insufficient to reduce spalling depth below 80 mm under the RWS curve. Companion segments containing 2.5 kg/m³ recorded residual spalling depths below 20 mm, although published data for specific aggregate mineralogies and moisture conditioning procedures is limited. Compliance is anchored to EN 14889-2:2006 Class I for polymer micro fibres, EN 1992-1-2:2004 for structural fire design, ISO 834-1:1999 for furnace test methodology, and national tunnel fire safety requirements such as the Dutch RWS curve and German ZTV-ING Part 7. Production on carousel mould lines employs high-frequency external vibrators operating at 50–100 Hz and steam curing at 60–80°C; neither process disturbs fiber integrity because the curing temperature remains far below the melting onset of 160°C.
Batching sequence controls dispersion. Fibers are introduced after dry blending of aggregates and cement but before the total water and superplasticizer dose, and wet mixing is extended at least 60 seconds in twin-shaft or planetary mixers to prevent fiber balling. At 3.0 kg/m³ the workability loss is measurable as a reduced slump of 20–40 mm compared with the same mix without fibers; superplasticizer dosage is adjusted to restore the target S4 consistency without adding water. The terminal products are precast segmental tunnel lining rings, typically 1.5–2.0 m wide and 250–500 mm thick, assembled by tunnel boring machines in metro, road, and rail tunnels. Operational boundary: remixing after slump loss by water addition is not permitted, and free-fall discharge into hoppers before vibration must not exceed 0.5 m to maintain fiber homogeneity.
Wet-mix sprayed concrete placed by robot manipulators in NATM tunnel headings imposes pumpability constraints that differ from cast-in-place or precast operations. Monofilament polypropylene micro fibres at 0.9–1.8 kg/m³ are batched at the ready-mix plant to control plastic shrinkage cracking in freshly sprayed layers, where the exposed surface area accelerates evaporation before the cement paste has developed sufficient tensile strain capacity. The fiber addition conforms to EN 14889-2:2006 Class I, and the sprayed concrete specification follows EN 14487-1:2005 with test methods drawn from the EN 14488 series. Batching uses twin-shaft or truck mixers; fibers are added to aggregates before water and mixed for at least 45 seconds beyond the standard wet mixing time. The concrete is delivered to a double-piston or screw pump at 10–20 m³/h and conveyed through a 50–65 mm diameter delivery line to the nozzle, where compressed air at 0.3–0.7 MPa accelerates the material and an alkali-free accelerator is injected at 4–8% by weight of cement depending on layer orientation and ground condition.
Rebound on production-scale walls typically measures 10–20% and is not significantly altered by monofilament micro fibres; the polymer is chemically inert to alkali-free and alkali-based accelerator chemistries. The fibres do not provide post-crack residual flexural capacity, so tunnel support requiring energy absorption is specified with steel or synthetic macro fibres under EN 14487-1:2005 performance classes. Layer thickness per pass is maintained at 50–150 mm, and subsequent passes are applied only after the previous layer has achieved initial set. Terminal products include primary shotcrete linings in NATM rail and road tunnels, rock slope stabilization shells, underground mine drift linings, and temporary support shells used until a cast-in-place final lining is installed.
Carousel precast production lines demould elements at concrete ages as early as 6–8 hours when steam curing is applied, and the lifting operation introduces concentrated tensile stresses at edges, corners, and anchor zones before the matrix reaches its 28-day tensile strength. Addition of monofilament polypropylene micro fibre at 0.6–1.0 kg/m³ inhibits crack edge propagation during demolding, stacking, and transport shocks. The function is not to increase compressive strength but to localise strain and prevent single microcracks from propagating into visible edge spalls. Compliance for the fibre itself is EN 14889-2:2006 Class I, while the precast products fall under EN 13369:2023 common rules and specific product standards such as EN 1917 for concrete manholes and EN 14844 for box culverts. Factory production control is documented under ISO 9001 or the relevant notified body certification for CE marking under the Construction Products Regulation.
Batching is performed in planetary or twin-shaft mixers with fibres added in pre-weighed bags to the aggregates before cement and water; mixing time is extended 30–60 seconds beyond plain concrete. Casting systems include tilting tables for wall panels, extrusion machines for hollow core slabs, and vertical or horizontal carousel moulds for manholes and culverts. Compaction uses external high-frequency vibrators at 3,000–6,000 rpm or table vibrators; the low density of polypropylene at 0.91 g/cm³ requires that vibration duration remains within the mix-specific optimum to avoid upward fiber migration and surface blemishes. Demoulded surfaces may exhibit occasional monofilament ends; for non-architectural elements this is considered acceptable, while architectural precast panels require secondary surface finishing. Terminal product types include box culverts, concrete manhole sections, retaining wall panels, and hollow core slabs for building and civil works. Published data for specific fiber distribution in extruded hollow core lines is limited.
Large-area ground-bearing slabs for logistics facilities are placed in single pours exceeding 1,000 m² per day using laser-guided screeds that strike off concrete at paving widths of 3–6 m and follow pre-programmed elevation data. The placement environment creates a high evaporation surface across the entire pour; when the evaporation rate exceeds 0.25 kg/m²/h, the threshold identified in ACI 305R for hot-weather concreting, plastic shrinkage cracks can appear within 6 hours of placement. Monofilament polypropylene micro fibre is added at 0.9 kg/m³ at the batch plant under ASTM C1116/C1116M Type III synthetic micro fibre specification to reduce restrained plastic shrinkage cracking measured by ASTM C1579. The slab construction specification is typically ACI 302.1R-15, and floor tolerance acceptance is evaluated under ASTM E1155 for FF and FL numbers.
Delivery uses ready-mix trucks with fibre already dispersed; job-site addition of loose fibers into truck mixers is permissible only with at least 5 minutes of mixing at full speed and is followed by a visual check for fiber balls, while plant pre-blended dosing remains the preferred route. Placing crews operate ride-on power trowels after laser screeding, and curing compound meeting ASTM C309 is sprayed immediately after the final trowel pass to limit surface evaporation. The fiber addition does not replace saw-cut joints, dowels, or load-transfer devices; joint spacing remains governed by slab thickness and subgrade restraint per ACI 360R. Terminal applications include warehouse floors, cross-dock logistics terminals, food and beverage processing floors, and light-industrial manufacturing slabs where continuous floor use and flatness tolerances are specified.
Thin bonded repair overlays placed at 25–75 mm thickness on bridge decks and parking garage slabs have surface-to-volume ratios high enough to accelerate bleed-water evaporation and plastic shrinkage cracking before the repair material develops bond to the prepared substrate. Monofilament polypropylene micro fibre is dosed at 0.9–1.2 kg/m³ to suppress restrained plastic cracking measured under ASTM C1579, with the upper bound used for overlays thinner than 40 mm and for silica fume-modified repair mortars with low bleed characteristics. Compliance for structural repair materials is governed by EN 1504-3 performance class R4, which requires compressive strength of at least 45 MPa and pull-off bond strength of at least 2.0 MPa at 28 days for structural use. Surface preparation follows ICRI Guideline No. 310.2R with concrete surface profile of CSP 5–8 produced by hydrodemolition or scarification before the bond coat is applied.
The downstream process uses mobile continuous mixers or mortar mixers with fibre pre-blended into dry repair material or added separately at the batching stage; mixing time is extended 45–60 seconds after all components are charged. Placement proceeds with gauge rakes and screeds in widths matched to the working time of the repair mortar, and the surface is closed with steel trowels. Curing is critical: wet burlap or continuous water curing is maintained for 7 days, or a curing compound meeting ASTM C309 is applied, because thin overlays lose water rapidly and early drying compromises bond strength. Terminal repair products include bridge deck overlays, parking garage slab repairs, industrial floor patch overlays, and reinforced concrete pavement partial-depth repairs. Operational limitation: PP micro fibres do not compensate for insufficient substrate preparation or chloride contamination, and repair failure modes at bond lines are governed by substrate tensile strength rather than fibre dosage.
Slipform pavement construction places concrete against vertical side forms and removes the forms continuously as the paver advances, leaving the fresh edge unsupported until curing matures. Concrete with slump values between 20–40 mm is required to maintain edge geometry, but this low workability combined with dowel bar insertion and high-frequency vibration can produce edge slumping and early-age cracking at the slab shoulder. Monofilament polypropylene micro fibre is added at 0.9–1.3 kg/m³ under ASTM C1116/C1116M Type III to control plastic shrinkage cracking during the first 6–8 hours and to reduce edge slump-induced cracking at the unsupported shoulder. Pavement construction guidance follows ACI 325.9R for highway pavements and FAA P-501 for airfield concrete pavement when the work is under federal aviation jurisdiction.
The batching and placing system includes central mix plants or volumetric mobile mixers delivering to a slipform paver equipped with hydraulic vibrators operating at 5,000–9,000 vpm; paver speed is maintained between 0.8–1.5 m/min depending on depth and design consistency. Longitudinal tine texturing and curing compound application occur immediately after the trailing forms pass. Because polypropylene has a density of 0.91 g/cm³, vibration frequency and duration are calibrated to the mix design to avoid fiber migration into the top 10 mm of the slab, which can produce surface fuzzing under tining. Terminal products include jointed plain concrete highway pavements, airport taxiways and aprons, container terminal pavements, and mine haul road concrete sections. The fibre does not replace dowels, tie bars, or structural reinforcement, nor does it alter joint spacing calculations under ACI 325.12R or equivalent national pavement design codes.
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SikaFiber PP Micro-20 is specified as a monofilament polypropylene fiber for concrete, with the product designation indicating a nominal cut length of 20 mm. The fiber is positioned functionally as a plastic shrinkage crack control agent rather than a structural reinforcement system, and it falls under the generic scope of Type III synthetic fiber-reinforced concrete in ASTM C1116/C1116M. Polypropylene exhibits a specific gravity of 0.91 g/cm³ when assessed in accordance with ISO 1183-1:2019, allowing the fiber to disperse throughout normal-weight concrete without the settlement tendency observed with steel macro-fibers. The polymer is hydrophobic, with water absorption below 0.1% by ASTM D570, and it is generally inert to the alkaline cementitious environment at pH 12 to 13. Published independent test data for this specific product configuration is limited; therefore, batch-release values and dosage limits should be verified against the current manufacturer technical data sheet.
The following reference values are class-typical for monofilament polypropylene concrete fibers and are not presented as a batch certificate for SikaFiber PP Micro-20. Conformity and project-specific values require confirmation through the supplier documentation and current CE marking documentation where applicable.
| Parameter | Class-typical range or value | Test method |
|---|---|---|
| Material configuration | Monofilament polypropylene | Supplier data |
| Nominal length | 20 mm | Supplier data |
| Specific gravity | 0.91 g/cm³ | ISO 1183-1:2019 |
| Tensile strength | 300 MPa to 400 MPa | ISO 527-2 |
| Modulus of elasticity | 3.5 GPa to 4.0 GPa | ISO 527-2 |
| Melting temperature | 160 °C to 170 °C | ISO 11357-3:2018 |
| Water absorption | <0.1% | ASTM D570 |
| Alkali resistance | No degradation at pH 12 to 13 | EN 14889-2:2006 |
| Typical dosage | 0.6 kg/m³ to 0.9 kg/m³ | Manufacturer documentation, trial batching |
At concrete level, product conformity is assessed under EN 14889-2:2006 when CE marking is applied. The manufacturer is responsible for declaring fiber geometry, density, tensile strength, and alkali resistance under factory production control. The designation under ASTM C1116/C1116M establishes material classification but does not by itself define a plastic shrinkage performance limit; restrained cracking evaluation should be performed using ASTM C1579 or a comparable project-specific protocol. The melting range between 160 °C and 170 °C is relevant in fire-spalling assessments because polypropylene fibers can melt and create microchannels for vapor pressure release, but this behavior is accompanied by complete loss of fiber tensile capacity at those temperatures.
At the batch plant, SikaFiber PP Micro-20 is introduced after coarse aggregate, fine aggregate, and cementitious binders are charged and before the final water adjustment. In a twin-shaft compulsory mixer, a wet mixing duration of 60 seconds to 90 seconds at peripheral tip speeds between 1.5 m/s and 2.0 m/s is typically sufficient for full fiber separation. In truck-mix operations, 70 to 90 revolutions at the drum’s rated mixing speed, commonly 12 rpm to 16 rpm, are used before discharge. A known production failure is dry fiber clumping when the product is added into a stationary mixer through a narrow opening or directly onto a high-velocity water stream; such clumps can survive normal mixing and accumulate on a concrete pump hopper screen with an aperture of 40 mm to 80 mm. Because polypropylene water absorption is below 0.1%, pre-drying is generally not required in intact packaging, but opened bags stored at relative humidity above 60% may develop surface moisture that affects feeding accuracy and batching weight.
Plastic shrinkage cracking becomes the controlling performance risk when the evaporation rate from the fresh concrete surface exceeds the bleed-water supply rate, producing capillary menisci and tensile stress within the first 2 hours to 6 hours after placement. The 20 mm monofilament fibers act as distributed tensile elements in the plastic paste, intercepting bleed channels and reducing crack width before the concrete develops sufficient tensile strength to resist restraint stress. At a dosage of 0.9 kg/m³, the theoretical fiber count exceeds approximately 0.7 million fibers/m³ for a 0.03 mm diameter monofilament; this estimate is derived from geometric calculation and class-typical cross-section, and the actual count depends on the declared denier or diameter from the supplier. In restrained slab tests conducted in accordance with ASTM C1579, plastic shrinkage crack area reductions of 40% to 80% relative to an unreinforced reference mix are commonly reported for monofilament polypropylene micro-fibers at 0.9 kg/m³. Published independent data for this specific SKU is limited, so project-specific validation remains necessary for performance-based specifications.
The fiber does not prevent evaporation, and it is not a substitute for fogging, curing compounds, windbreaks, or early moist curing. ACI 305R-10 identifies evaporation rate, air temperature, concrete temperature, relative humidity, and wind speed as the primary placement variables governing plastic cracking risk. SikaFiber PP Micro-20 should be considered a supplementary mitigation layer rather than a replacement for moisture retention. In power-trowelled industrial floors, the monofilament form may reduce surface fuzzing compared with fibrillated polypropylene products, but trowel timing and blade angle require adjustment because fibers can be drawn from the paste during the first pass. Addition rates above 1.0 kg/m³ are generally not specified without a trial batch due to increasing slump loss, pump-line backpressure, and trowel-induced surface fuzzing. In high-strength concrete exposed to fire, the melting of polypropylene at 160 °C to 170 °C can create permeable microchannels that reduce vapor pressure and may lower explosive spalling risk; however, design fire tests are required because moisture content, heating rate, section geometry, and stress state govern the actual spalling response.
In comparison to cold-drawn steel fibers, SikaFiber PP Micro-20 has a much lower specific gravity, 0.91 g/cm³ versus approximately 7.85 g/cm³, and a tensile modulus approximately two orders of magnitude lower than the 200 GPa typical of steel macro-fibers. The practical consequence is that the monofilament polypropylene product does not provide post-crack residual flexural strength comparable to steel macro-fibers when tested under ASTM C1609/C1609M; its design function is early-age plastic shrinkage control and not structural moment redistribution. In comparison to macro synthetic fibers with lengths of 30 mm to 60 mm and engineered crimped or embossed geometries, the 20 mm monofilament is intended for fine, high-count distribution and crack-width control before final set rather than for post-crack load transfer in hardened concrete. Compared with fibrillated polypropylene micro-fibers, the monofilament configuration generally disperses with lower mixing energy, but comparative water demand, finishability, and air-entrainment interaction should be evaluated for the specific mix because aggregate angularity, paste volume, and admixture chemistry influence fiber distribution and surface appearance.
The table below compares product classes using published typical values and standard test frameworks. Values are class-typical rather than batch-release data for any named product.
| Parameter | SikaFiber PP Micro-20 | Cold-drawn steel macro-fiber | Macro synthetic fiber |
|---|---|---|---|
| Fiber material | Monofilament polypropylene | Cold-drawn steel | Polyolefin macro-fiber |
| Nominal length | 20 mm | 30 mm to 60 mm | 30 mm to 60 mm |
| Specific gravity | 0.91 g/cm³ | 7.85 g/cm³ | 0.90 g/cm³ to 0.95 g/cm³ |
| Tensile modulus | 3.5 GPa to 4.0 GPa | 200 GPa | 3 GPa to 10 GPa |
| Primary function | Plastic shrinkage crack control | Post-crack flexural capacity | Post-crack flexural capacity |
| Post-crack residual strength under ASTM C1609/C1609M | Negligible | Significant | Moderate |
| Corrosion risk | None | Possible in cracked chloride-exposed concrete | None |
| Typical dosage | 0.6 kg/m³ to 0.9 kg/m³ | 20 kg/m³ to 40 kg/m³ | 3 kg/m³ to 9 kg/m³ |
Operational boundaries define the product’s appropriate application envelope. SikaFiber PP Micro-20 is not acceptable as primary reinforcement in structural members where bar reinforcement is required by ACI 318-19, EN 1992-1-1, or equivalent structural concrete codes. The fiber is also not designed to restore post-crack load-bearing capacity evaluated by ASTM C1399/C1399M or ASTM C1609/C1609M. Storage should protect the fiber from direct sunlight and moisture; wet packaging can affect fiber feeding and batching accuracy even though polypropylene water absorption is below 0.1%. The product is not intended for continuous service above the polypropylene melt range of 160 °C to 170 °C, and it should not be used where its melting would create unacceptable void connectivity unless fire-spalling behavior is explicitly engineered and validated. Air-entrained mixes require post-addition air content verification because hydrophobic fibers can interact with admixture dosage and mixing air content; batch-to-batch air content should be checked under ASTM C231/C231M or ASTM C173/C173M. For CE-marked applications, the incoming product must be accompanied by an EN 14889-2:2006 conformity document, and dosage must not exceed the upper bound used in the conformity assessment unless additional trial batching is performed.
