Global supplier of
High-Performance Materials

Polypropylene Fiber

Polypropylene (PP) Fiber （also known as PP Monofilament Fiber）, a high-performance synthetic fiber derived from polypropylene resin, is renowned for its exceptional versatility and reliability in diverse industrial applications with the construction sector standing as its primary field of use. As a premium reinforcement material, it plays a pivotal role in enhancing concrete structural integrity, effectively mitigating initial plastic cracking, and improving overall durability of cement-based composites. 

Our PP Fiber is specifically engineered as an anti-cracking and anti-seepage engineering fiber for mortar and concrete. The manufacturing process involves blending modified masterbatches with polypropylene chips, followed by melt spinning and stretching. The base material is modified polypropylene, which undergoes specialized anti-static and anti-ultraviolet treatments to ensure long-term performance stability when uniformly dispersed in concrete matrices. 

A key design feature is the fiber’s trilobal cross-section, which significantly increases its specific surface area. Additionally, through chemical grafting and physical modification, the fiber surface exhibits a rough, porous structure—greatly enhancing the bonding strength between the fiber and cement-based aggregates. Owing to its fine diameter and large specific surface area, approximately 45 fibers are distributed per cubic centimeter of concrete, forming a random three-dimensional supporting network. This network effectively controls the initiation and propagation of non-structural cracks (such as plastic shrinkage and drying shrinkage cracks) in concrete and cement mortar at the early stage, inhibits aggregate segregation, prevents settlement cracking, substantially improves project quality, and reduces long-term maintenance costs.

What are the key features and advantages of PP monofilament fiber?

-Excellent Alkali Resistance: Maintains stable performance in the alkaline environment of cement and concrete, avoiding degradation and ensuring long-term reinforcement effectiveness.

-High Tensile Strength & Modulus: Boasts superior tensile strength and elastic modulus, providing reliable reinforcement for concrete structures and enhancing their load-bearing capacity.

-Robust Environmental Resistance: Resists corrosion from most chemicals, moisture, and UV radiation, maintaining structural integrity even in harsh outdoor or industrial environments.

-Low Thermal Expansion Coefficient: Matches the thermal expansion characteristics of concrete, minimizing thermal stress-induced cracking and shrinkage during temperature fluctuations.

-Effective Crack Inhibition: The three-dimensional network structure controls the formation and development of intrinsic cracks, improving the impermeability and durability of concrete.

-Easy Dispersion & Mixing: Integrates quickly and uniformly with mortar and concrete materials, requiring no special mixing equipment and ensuring consistent performance across the matrix.

Technical Data:

What applications are PP monofilament fiber utilized for? 

Polypropylene Fiber is widely utilized across multiple industries, with its core applications centered in construction and civil engineering. Key use cases include:

-Concrete Structure Reinforcement: Used in bridges, tunnels, high-rise buildings, dams, and precast concrete components to enhance tensile strength, toughness, and impact resistance, while reducing cracking and shrinkage.

-Infrastructure Projects: Applied in road pavements, airport runways, and railway platforms to improve fatigue resistance and extend service life.

-Specialty Construction: Reinforces shotcrete for mine shafts, slope protection concrete, and waterproof concrete for basements and reservoirs, enhancing anti-seepage performance.

-Geotechnical Engineering: Aids in soil stabilization for embankments and retaining walls; used in erosion control blankets for riverbanks and slopes.

-Asphalt Pavements: Serves as a binding agent in asphalt mixtures to improve high-temperature stability and low-temperature crack resistance of pavements.

How to store and handle PP monofilament fiber? 

When it comes to storage, PP fiber should be kept in a cool and dry place away from direct sunlight. It should also be kept away from any chemicals or substances that could damage the fiber. It is recommended to store the fiber in a sealed container to maintain its quality and prevent any contamination.

-Store in a cool, dry, and well-ventilated warehouse, avoiding direct sunlight and high-temperature environments (exceeding 40℃) to prevent fiber aging.

-Keep away from strong acids, alkalis, oxidants, and flammable substances to avoid chemical degradation.

-Use sealed packaging (original PE and woven bags) to prevent moisture absorption, contamination, or fiber agglomeration. Once opened, reseal the package promptly after use.

-Stack packages neatly, with a maximum stacking height of 5 layers to prevent crushing and deformation of the inner packaging.

-The recommended shelf life is 24 months under proper storage conditions. For long-term storage, regular inspection of packaging integrity is advised.

FAQ

Question 1: How is the PP fiber packaged?

A: Our standard packaging is 1kg per inner PE bag, with 20kg packed into one outer plastic woven bag (equipped with moisture-proof and dust-proof liners). Customized packaging (such as different inner bag weights, printed logos, or palletized packaging) is available upon request to meet your logistics and branding needs.

Question 2: Can the PP fiber length and performance be customized?

A: Yes, we provide comprehensive customization services. We can adjust fiber length (3–24 mm), diameter, tensile strength, and add special functional treatments (such as enhanced UV resistance) according to your specific application scenarios (e.g., thin-plate concrete vs. mass concrete). Please share your technical requirements with our R&D team for a tailored solution.

Question 3: What is the typical lead time for an order of PP fiber?

A: For standard products, the lead time is 3–7 working days after receiving the advance payment. For customized orders or large quantities (exceeding 50 tons), the lead time is 10–15 working days, depending on the production schedule. We will provide a detailed delivery timeline upon order confirmation.

Question 4: What is the optimal mixing sequence of PP Fiber with concrete to ensure uniform dispersion, and how to avoid fiber agglomeration?

A: The recommended mixing sequence follows the "dry mixing first, wet mixing later" principle: 1) Add coarse aggregate and fine aggregate into the mixer, dry mix for 30 seconds to homogenize; 

2) Add the designed dosage of PP Fiber, continue dry mixing for 60–90 seconds to make fibers adhere to aggregate surfaces (preventing floating); 

3) Add cement, fly ash, and other binders, dry mix for 30 seconds; 

4) Finally add mixing water and admixtures, wet mix for 120–180 seconds. 

To avoid agglomeration, do not add fibers directly into water or admixture solution, and ensure the mixer’s rotation speed is maintained at 18–22 r/min during dry mixing. For small-scale mixers (≤500L), reduce single fiber dosage and extend dry mixing time by 30 seconds.

Question 5: How does PP Fiber compare with traditional steel fiber in concrete reinforcement, and what are the applicable scenarios for each?

A: The two fibers have distinct positioning: 

1) Reinforcement Mechanism: PP Fiber forms a three-dimensional network to control micro-cracks and improve toughness, while steel fiber mainly enhances tensile and flexural strength by bearing macro-stress. 

2) Performance Advantages: PP Fiber is lightweight (density 1/8 of steel), corrosion-resistant (no rust in humid/alkaline environments), and easy to construct (no damage to formwork); steel fiber has higher modulus (≈200 GPa vs. 3.5 GPa of PP) and better load-bearing capacity. 3) Applicable Scenarios: PP Fiber is suitable for crack prevention in ordinary concrete (floors, walls, precast panels) and harsh environments (coastal, chemical plants); steel fiber is preferred for high-load structures (bridge decks, industrial ground, shotcrete for mine shafts) requiring high flexural strength.

Question 6: Can PP Fiber improve the freeze-thaw resistance of concrete, and what technical parameters should be focused on in cold regions?

A: Yes. PP Fiber enhances freeze-thaw resistance by two mechanisms: 

1) The fiber network inhibits the expansion of ice crystals in concrete pores, reducing internal stress; 

2) It reduces drying shrinkage cracks, decreasing the number of water penetration channels. 

For cold regions (average temperature ≤ -10℃ in winter), focus on three parameters: a) Fiber Length: 12–18mm is optimal (shorter fibers have weak crack resistance, longer ones are easy to agglomerate); b) Tensile Strength: ≥500 Mpa (to resist repeated freeze-thaw stress); c) Elongation at Break: 15%–25% (ensuring flexibility during volume changes). It is also recommended to increase the fiber dosage to 1.5–2.0 kg/m³ and cooperate with air-entraining agents (air content 4%–6%) for better performance.

Question 7: Is PP Fiber suitable for self-compacting concrete (SCC), and will it affect the passing ability and filling ability of SCC?

A: Our modified PP Fiber is specially optimized for SCC. The key to compatibility lies in fiber morphology and dosage: 1) We use a smooth-surface trilobal section design to reduce friction with aggregates, and the fiber diameter is controlled at 20–28μm (thinner than standard fibers) to minimize interference with paste flow. 2) The recommended dosage is 0.6–1.2 kg/m³; when the dosage is ≤1.0 kg/m³, the slump flow of SCC decreases by ≤10mm, and the L-box passing ratio is ≥0.85 (meeting GB/T 50448 requirements). For SCC with high fluidity (slump flow ≥750mm), we suggest using our "low-viscosity adaptive" PP Fiber, which can further reduce the impact on workability. A small-batch trial mix is recommended before large-scale application to confirm the matching performance.

Question 8: How to evaluate the long-term anti-cracking effect of PP Fiber in concrete?

A: The long-term anti-cracking effect is evaluated by two core indicators: 1) Crack Width Control: After 2 years of natural curing, the maximum width of non-structural cracks in concrete mixed with PP Fiber should be ≤0.1mm (vs. 0.2–0.3mm for plain concrete). 2) Flexural Toughness Retention Rate: ≥80% of the initial value after 5 years of service.