Applications of Polypropylene Fiber in Concrete
Release Time:
2021-05-03
Source:
Polypropylene fibers undergo special antistatic and ultraviolet-resistant treatments, ensuring uniform dispersion within concrete and enabling long-term performance; the “Y”-shaped cross-section of the polypropylene fibers increases their surface area; furthermore, chemical and physical modifications impart a rough, porous surface, significantly enhancing the fiber–cementitious aggregate interface. Binding force.
Main advantages of polypropylene fiber:
1) Excellent dispersibility and strong binding force;
2) High acid and alkali resistance; high radiation resistance;
3) Freeze resistance and corrosion protection, with enhanced strength and toughness;
4) Physical reinforcement for crack resistance and structural strengthening;
5) Stable performance, safe and non-toxic;
6) Simple construction, economical and reliable;
Superior properties of PP fibers:
1. Enhance crack resistance;
2. Enhance impermeability;
3. Enhance impact resistance and wear resistance;
4. Enhance freeze resistance;
5. Enhance resilience;
6. Enhance the product’s fire resistance and improve its blast-resistant performance;
7. Improve product quality.
Polypropylene fibers are primarily used in concrete for the following purposes:
1) Preventing plastic shrinkage cracks in concrete. During the setting and hardening process, surface moisture loss in concrete can lead to plastic shrinkage and cracking; however, incorporating polypropylene fibers into concrete can effectively prevent such cracking. Since the elastic modulus of polypropylene fibers is lower than that of hardened concrete, this has a beneficial effect on the crack-resistant performance of hardened concrete (temperature Cracking induced by stress or mechanical loading is limited, with only modest improvements in tensile and flexural strength, though some enhancement in concrete toughness can be observed.
2) Enhancing the fire resistance of hardened concrete. Under high-temperature exposure, polypropylene fibers first soften and burn away, creating numerous pores within the concrete. These pores allow the moisture vaporized by the heat to escape, thereby preventing internal pressure buildup from vaporization that could lead to concrete spalling or cracking, thus significantly improving the concrete’s performance. Fire resistance duration and fire-resistance rating of concrete.
3) Enhancing the impermeability of concrete: The incorporation of fibers effectively inhibits segregation in cement concrete, thereby improving the overall homogeneity of the placed concrete; it significantly reduces the number, length, and width of cracks, lowers the likelihood of through-cracks forming, and acts to block capillary cracks within the concrete, thus enhancing the concrete’s resistance to… The permeability is significantly improved. At the same time, the migration rates of water, chloride ions, and air within the concrete are reduced, thereby delaying the corrosion of reinforcing steel.
4) Enhancing the toughness and fatigue resistance of concrete and improving its resistance to impact and abrasion: The incorporation of fibers into the cement matrix reduces the brittleness of cement concrete and increases the toughness of the matrix. Fiber-reinforced cement concrete can withstand tens of thousands, even millions, of cycles of repeated stress at its static strength while still maintaining good performance. state. This characteristic is advantageous for certain cement-concrete structures that are frequently subjected to impact fatigue, such as roads, sidewalks, pavement overlays, and warehouse flooring.
