What’s the Difference When Adding PPF and PAN Fiber to Concrete?


Concrete is a widely used construction material known for its strength, durability, and versatility. Over the years, researchers and engineers have explored various ways to enhance concrete properties to meet the demands of different applications. One such method is the addition of synthetic fibers as reinforcement.


Polypropylene fiber (PPF) and polyacrylonitrile fiber (PAN fiber) are two commonly used types of concrete fibers. In contrast, they both contribute to improving the performance of concrete. And they have distinct characteristics that set them apart. In this blog, we will delve into the differences between PPF and PAN fiber. And their effects on concrete properties and their respective advantages.









Polypropylene Fiber(PPF)


PPF is a concrete fiber derived from the polymerization of propylene monomers. It is widely employed as a reinforcement material in concrete due to its favorable properties. PPF offers several fiber reinforcement benefits: lightweight, high tensile strength, impact resistance, and crack control in concrete. These qualities make it an excellent choice for applications where reducing weight and increasing durability are crucial factors.


The density of PPF typically ranges from 0.87 to 0.95 g/cm3, depending on its crystallinity. This low density contributes to the lightweight nature of the fiber and ensures that it does not significantly increase the weight of concrete. Additionally, the high tensile strength of PPF allows it to distribute and transfer stress within the concrete matrix effectively. This enhances the material’s overall performance.


One noteworthy characteristic of PPF is its impact and crack formation resistance. The fibers act as a reinforcement network, bridging the cracks that may occur in the concrete. This bridging effect helps prevent crack propagation and improves the overall durability of the structure. Moreover, the impact resistance of PPF plays a vital role in applications susceptible to dynamic loads or potential impact events.


However, it’s important to note that PPF has a relatively low elastic modulus compared to ordinary concrete. The elastic modulus determines the stiffness of a material, while PPF provides other desirable properties. Its lower modulus can impact certain applications where higher stiffness is required.









Polyacrylonitrile Fiber(PAN Fiber)


Polyacrylonitrile fiber, also known as PAN fiber or acrylic fiber. It is another widely used synthetic fiber in fiber-reinforced concrete. PAN fiber is a copolymer composed of acrylonitrile monomers with additional monomers. This fiber exhibits distinct characteristics that differentiate it from PPF.


PAN fiber has a higher elastic modulus, tensile strength, and aspect ratio than PPF. The aspect ratio refers to the length-to-diameter ratio of the fibers. The higher aspect ratio of PAN fiber allows for better stress distribution and transfer within the concrete matrix. It results in improved crack resistance and overall mechanical properties.


One notable advantage of PAN fiber is its excellent freeze resistance. The elastic modulus of PAN fiber increases at lower temperatures. It is particularly beneficial in regions with harsh winter climates. The enhanced freeze resistance helps prevent damage caused by freeze-thaw cycles. It can reduce the risk of cracking and improve concrete structures’ long-term durability.


Similar to PPF, PAN fiber exhibits good bonding with the cementitious matrix. The hydrophilic nature of PAN fiber promotes strong adhesion between the fibers and the surrounding concrete. This enhanced bonding further improves crack resistance and the overall performance of reinforced concrete.








PAN Fiber vs. PPF: Performance Comparison


When comparing the performance of PPF and PAN fiber in concrete, several key factors come into play:


Compressive Strength


Due to its molecular chain structure, PPF has an elastic modulus of only about 1/10 to 1/8 of ordinary concrete. It is difficult for the fiber to withstand stress directly, but it has a good stress transfer effect. Therefore, it does not significantly impact the compressive strength of concrete.


PAN fiber generally improves the compressive strength of concrete. Compared to PPF, PAN fiber has a smaller diameter (approximately twice that of PPF) and a larger quantity. This affects the bonding condition between adjacent fibers. The polar groups on the fiber surface provide good hydrophilicity, promoting the bonding between the fiber and the matrix. The higher specific surface area ensures a more uniform distribution of fibers and better stress transfer. The higher fiber strength and elastic modulus also enhance the crack resistance.







Flexural Performance


Due to the hydrophilicity of PAN fiber, insufficient hydration occurs at the interface at 28 days. On the other hand, the bonding performance of the fiber is good, and the test results mostly exhibit tensile fracture. The fewer and longer fibers in the cross-section tend to experience tensile fracture. However, this does not mean that there is no fiber slippage. Therefore, the influence mechanism of PAN fiber on flexural strength is significantly more complex than that of PPF.


PPF has poor bonding, and slippage occurs in all test specimens upon failure. The failure mechanism is relatively simple. With similar but slightly different patterns among different fiber lengths. The key factors affecting the flexural strength of PPF are strength and hydrophilicity. And bonding condition plays a crucial role in PAN fiber.








Impact Resistance


Both fibers effectively improve the impact resistance of concrete. Although flexible fibers, they exhibit different energy dissipation mechanisms during failure. Regarding complete failure, PAN fiber is pulled chiefly apart, while PPF is partially pulled apart. With its good bonding, PAN fiber tends to fracture without sufficient deformation during impact. It primarily relies on fiber fracture to absorb the energy.

On the other hand, PPF has a larger diameter and higher tensile strength. This allows for significant elongation during crack propagation. Its impact resistance to concrete can be attributed to bridging the crack surfaces to prevent the crack formation and the resistance offered by fiber extraction or fracture to inhibit crack propagation.










PAN and PPFs both contribute to the durability of concrete. They improve the resistance to freeze-thaw cycles. It can reduce shrinkage cracking and enhance the overall toughness of the material. However, it’s important to note that the specific performance of the fibers in terms of durability may differ depending on factors. For example, the fiber content, aspect ratio, and mix design.










Conculsion & WOTAIchem: Leading Concrete Fiber Supplier


In conclusion, adding polypropylene fiber (PPF) and polyacrylonitrile fiber (PAN fiber) to concrete offers significant benefits in terms of strength, durability, and performance. PPF provides lightweight reinforcement, high tensile strength, impact resistance, and crack resistance. This makes it an excellent choice for various concrete applications. On the other hand, PAN fiber exhibits a higher elastic modulus, tensile strength, and freeze resistance, enhancing the overall durability of the concrete. The fiber dosage in concrete for should be adjusted according to specific construction application requirements.



At WOTAIchem, we understand the importance of utilizing advanced materials to optimize concrete performance. As a polypropylene fiber supplier and PAN fiber manufacturer, our extensive expertise and innovative solutions. We are committed to providing you with top-quality PPF and PAN fiber products that meet your specific project requirements. Our fibers are carefully engineered to enhance the properties of your concrete. It helps in ensuring stable and resilient structures.


Take your construction projects to new heights with WOTAIchem’s premium solutions. WOTAIchem’s professional team of experts is dedicated to delivering exceptional products and outstanding OEM solutions. Contact us today to discuss your concrete reinforcement solutions and discover how our PPF and PAN fiber products can elevate your projects to the next level.


Remember, when it comes to strengthening and enhancing concrete, WOTAIchem is your trusted partner. Choose WOTAIchem for reliable and high-performance fiber solutions that exceed your expectations.




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Posted by Isabel

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