Warm Global Customers
With China Plastic Machinery
With China Plastic Machinery
Polypropylene fiber net, also known as mesh fiber, is a 100% polypropylene product produced from non-renewable raw materials. The raw materials are selected after repeated experiments and processed by fiberization technology. In principle, adding fiber net to concrete does not change the design ratio of concrete, and its addition does not affect the use of other concrete admixtures to improve the fatigue strength of shotcrete and reduce rebound loss.
Polypropylene fiber net, also known as concrete with mesh fiber, is a 100% polypropylene product produced from non-renewable raw materials. Its raw materials are selected after repeated experiments and processed by fiberization technology. Its original state is in a clustered state (each bundle contains 5-8 small bundles), and each small bundle is in a mesh shape after unfolding. At the beginning of fiber mixing, it is easy to disperse in the mixing to form a preliminary uniform distribution due to its bundle shape; in the middle of mixing, each small bundle of fibers is impacted by aggregates and unfolded into a mesh shape, and each mesh wire is wrapped with cement; as the mixing deepens, the mesh wire is completely torn apart, and finally the uniform distribution of monofilament fibers is completed. If 0.9kg is added to each cubic meter of concrete, there will be more than 7 million fibers distributed in a three-dimensional shape, which will improve and interweave into a network, and complement each other's concrete performance.
In principle, adding fiber mesh to concrete does not change the design ratio of concrete, and its addition does not affect the use of other concrete admixtures.
Additional proportion: The standard dosage is 0.9kg (1 bag), the high dosage is 1.8kg (2 bags), and the maximum dosage is 2.7kg (3 bags). That is, the amount of fiber mesh added to each cubic meter of concrete mortar is generally 0.9kg. The larger the amount added, the better the anti-cracking effect, but generally not more than 2.7kg.Fiber length: The recommended length of polypropylene fiber mesh for concrete is 19mm, and the length for cement mortar is generally 10-15mm.
Mixing time: When mixing, please put the fiber mesh, sand, aggregate, and cement into the mixer at the same time, then add water and mix. The mixing time should be no less than 3 minutes.
Mix design: The strengthening effect of the fiber mesh is a physical process, not a chemical process. There is no need to add water or change the concrete mix ratio in the concrete mix.
Mixer selection: Forced mixers are preferred. If there is no forced mixer and a self-falling mixer is used, the bag needs to be opened and the fibers are sprinkled in. First, dry mix with the aggregate for 1-2 minutes, then add water for wet mixing. The total mixing time is not less than 4 minutes.
When pouring and paving, appropriately extending the vibration time by 20 seconds can make the concrete denser and more conducive to the three-dimensional distribution of the fibers.
Increase the fire resistance of concrete: Since high-strength concrete has a very high density, the water vapor formed by the free water inside the concrete and the chemically decomposed water is difficult to overflow at high temperatures. After the fiber mesh is added to the concrete, since the concrete contains a large amount of chaotically distributed fibers, the fibers will first dissolve in the flame to form a channel for the water vapor to overflow, thereby preventing the components from bursting in the fire.
Improve the fatigue strength of shotcrete and reduce rebound loss: Polypropylene fiber mesh shotcrete is widely promoted in countries around the world because it can greatly improve the project and reduce the total cost. It has high viscosity, can form a thick concrete layer, and greatly reduce the rebound of concrete. According to on-site testing, fiber mortar can reduce material loss during spraying construction. When the fiber content is 0.9kg/m3, the rebound of mortar is reduced from the original 24% to 4-5%, thereby greatly reducing the use cost of shotcrete mortar.
Applicable to all types of concrete buildings
Road surfaces and guardrails of highways and expressways
Airport runways and aprons
Sprayed concrete on walls and tops of tunnels, mines, etc.
Dam, canal, reservoir, aqueduct, swimming pool, port, salt water construction
Composite floor slabs in building construction such as precast concrete panels and pipes
Main structure and pavement of bridges
Plastic cracking of concrete mainly occurs before the concrete hardens, especially within 4-5 hours after the concrete is poured. During this stage, plastic cracks inside the concrete are caused by the evaporation and transfer of water. After adding polypropylene fiber mesh to concrete, due to the uniform distribution of fibers, it plays a similar role as a screen, delaying or preventing the occurrence and development of early concrete plastic cracks, improving the continuity of the material medium, and significantly improving the performance of hardened concrete, thereby improving the impermeability of concrete, avoiding the corrosion of the stressed steel bars in the concrete from direct contact with moisture and chlorides, and increasing the corrosion resistance of concrete and the life of the building. Experiments show that compared with ordinary mortar concrete, the crack resistance of mortar concrete can be increased by about 70% by adding 0.1% (about 0.9kg/m3) polypropylene fiber mesh by volume.
The concrete is mixed with polypropylene fiber mesh treated by a special process. It has a strong bonding force with the cement base material and can be quickly mixed with the concrete. A uniform random support system is formed inside the concrete. When they are subjected to tension and impact, the uniformly distributed and numerous fibers act as reinforcing bars that absorb energy and share tension. Therefore, concrete containing fiber mesh has the ability to resist impact and earthquake. Experimental data show that if 0.1% (0.9kg/m3) of polypropylene fiber mesh is added to C50 concrete, its impact resistance is 1.65 times higher than that of ordinary C50 concrete. This feature is very useful for concrete structures susceptible to fatigue impact, such as roads, parking lots, aprons, airport runways, and national defense facilities.
After adding an appropriate amount of polypropylene fiber mesh to concrete, it can effectively inhibit the generation and development of early shrinkage microcracks and segregation cracks in mortar concrete, greatly reduce shrinkage cracks, and effectively inhibit the generation of through cracks. The evenly distributed and mutually bonded fibers play the role of "supporting" aggregates, reducing the water separation and aggregate segregation on the concrete surface, effectively ensuring uniform water seepage, thereby greatly reducing the content of pores with a diameter of 50-100nm and greater than 100nm (1nm=10=9m) in concrete, and improving the anti-seepage capacity of concrete by more than 60%. In concrete decomposition pools, basement projects, roofs, water tanks, exterior wall painting, etc., the use of polypropylene fiber mesh as a waterproof material to solve penetration has a significant effect.
Adding polypropylene fiber mesh to concrete can alleviate the internal stress of concrete caused by temperature changes and prevent the expansion of temperature cracks. According to the concrete antifreeze test method, after 25 repeated freeze-thaw cycles, no stratification and cracking occurred. Polypropylene fiber mesh has a macromolecular structure. When the external temperature is -40¡æ, the glassy and crystalline macromolecules have shrinkage resistance. This property just compensates for the thermal expansion and contraction characteristics of concrete mortar. Therefore, it can be widely used in cold areas as a concrete temperature difference compensation and crack resistance method.
High-strength concrete is an important development direction of concrete technology. It can adapt to the needs of modern engineering structures to develop in the direction of high span, high height and heavy load, and meet the requirements of modern construction technology to adopt industrialized production. However, high-strength concrete shows obvious brittleness in material mechanical properties, and the ultimate stress becomes smaller, which is easy to produce splitting phenomenon. These unfavorable factors affect the wider application of high-strength concrete. Polypropylene fiber mesh and cement base material have extremely strong bonding force, forming a uniform chaotic system inside the concrete. Observing the failure form of concrete specimens, it is found that ordinary concrete specimens are completely broken due to brittle failure; under the same experimental conditions, the fiber mesh concrete specimen has only two short cracks in different directions, and the specimen remains intact. This reflects that polypropylene fiber mesh can greatly improve the crack resistance and toughness of concrete, has a relatively ideal effect on overcoming the brittleness of high-strength concrete, and has very important engineering value.
Polypropylene fiber mesh concrete can control plastic settlement and plastic shrinkage cracking, and form a uniform film on the surface, which can enhance the wear resistance of concrete. Tests show that polypropylene fiber mesh concrete can increase the wear resistance by 50%, thereby doubling the service life of concrete under the same load conditions. It is especially suitable for parts of hydraulic structures that are severely damaged by hydraulic, sand and gravel scouring and wear.
Precautions for using polypropylene fiber mesh
Polypropylene fiber mesh is characterized by low elastic modulus, small specific gravity, and a large number of fiber roots. Its mechanism of action is to improve the continuity of the material medium by eliminating or reducing the number and size of the original cracks in the concrete, and the absorption of impact energy by organic materials, so that the impact resistance and fatigue resistance of concrete can be improved.
Polypropylene fiber mesh is non-hydrophilic and easily forms a weak interface effect. If the slag is ground, the synergistic effect of fiber and microparticles can be exerted, the contact area between fiber and substrate is enhanced, the characteristics of the interface are improved, and the debonding strength between fiber and interface is improved, so that the compressive and tensile strengths of concrete gradually increase with the hydration process of concrete.
It cannot be used alone to solve the cracks caused by settlement and impact by strong external forces.
The size of the main structure cannot be reduced due to the use of polypropylene fiber mesh.
Construction and maintenance cannot be carried out without following relevant national standards and practices due to the use of polypropylene fiber mesh.
When plastering, the surface of fiber concrete should be relatively passivated before plastering. Do not use overly rough plastering tools to avoid bringing out fibers.
The surface of concrete with fiber mesh has less water secretion because the uniform distribution of fibers prevents the movement of water. Do not sprinkle too much water in pursuit of a smooth surface, and do not plaster too many times.
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