1. What is polypropylene fiber mesh ?
The polypropylene fiber mesh is made of polypropylene baking as raw material and processed through a special process. Its appearance is a network structure formed by intersecting multiple fiber mono-filaments. (Know more about pp fiber)
It controls the micro-cracks caused by the plastic shrinkage, dry shrinkage, caused by the concrete, and prevents the formation and development of cracks. As a new type of anti-cracking fiber for concrete, concrete with mesh fiber is becoming a hot spot in the research and application of fiber concrete after glass fiber and steel fiber.
2. What is polypropylene fiber?
Polypropylene fiber is a high-strength bundled mono-filament fiber manufactured by unique processes with polypropylene resin as the main raw material. Adding polypropylene fiber into concrete or mortar can effectively control the cracks caused by plastic shrinkage, settlement, temperature change, and other factors. As a result, we prevent and the formation and development of cracks. It can be widely used in industrial and civil construction, water conservancy engineering, road and bridge engineering, etc.
3. What is the difference between PP fiber and PP fiber mesh?
PP fiber mesh:
● PP fiber mesh has better performance for high-strength concrete above C50.
● Fiber mesh is not easy to clump.
● The dosage of PP fiber is within 2 kg/m³, although the dosage can be up to 3 kg/m³ with PP fibers mesh.
● The main function of PP fiber is to control cracks at the concrete shrinks in the early stage. The diameter is about 20-50 µm, so the reinforcement effect on the later stage of concrete is not so significant.
4. What is the difference between polypropylene fiber and glass fiber?
● While mixing, glass fiber is easy to agglomerate. Improper operation will cause certain personal hazards. Polypropylene fiber has good dispersibility and does no harm to people.
● The number of fiber is far more than that of glass fiber in the same weight, so it can better improve crack resistance, anti-seepage, impact resistance, freeze-thaw resistance, and toughening of concrete.
● Glass fiber has poor alkali resistance. It is unstable in cement, and causes holes inside. so we do not suggest it.
5. What is the difference between virgin polypropylene and recycled polypropylene?
● Polypropylene is thermoplastic and recyclable.
● The quality of recycled polypropylene is unstable. So the quality of fibers will be different from each batch.
● Since recycled polypropylene has many impurities, the tensile strength and toughness are lower than the virgin one.
● The color of recycled polypropylene is dark.
6. What are the benefits of PP fiber for concrete?
Fiber reinforced concrete has a better tensile strength. Polypropylene fibers can slow down the settlement of coarse aggregates in concrete to reduce the bleeding rate. Then reduce the drying speed, thereby reducing plastic shrinkage and cracking.
7. What is the function of polypropylene fiber mesh?
PP fiber mesh for concrete can prevent and inhibit the formation and development of cracks caused by plastic shrinkage, dry shrinkage, temperature change.
8. What are the functions of polypropylene fibers?
When the polypropylene mesh fiber is put into the concrete, the transverse connection between the fiber mono-filaments can be destroyed by its own and friction action to form the fiber mono-filament or the net structure to fully expand during the mixing process of the concrete, so as to realize the quantity. Numerous polypropylene fiber mono-filaments can prevent concrete from cracking.
9. What should be noted to when using fiber reinforced concrete?
● The slump of fiber concrete should be strictly controlled. If the slump is too small, it is not easy to slide in the chute, and difficult to vibrate when entering the warehouse. The resistance is large, and the concrete is easy to crack. If the slump is too large, it is easy to separate in the chute, and the concrete is easy to collapse. the flatness of the concrete surface is poor, and strength cannot reach the design value. The best control range of slump: exit 4~6 cm, silo surface 2~3 cm.
● The fiber concrete slump loss is faster, (loses 1/2 in 0.5 hours). The slump is 0 after 1h. Thus, the transporting time must be limited within 15 minutes. Otherwise, the concrete should stay stable.
● We suggest construction under the temperature below 25℃.
10. What is the harm of too much fiber moisture?
Using fibers with high moisture content will cause the number of fibers to be insufficient, so concrete may crack at an early stage. The dosage of microfibers is less than 2 kg/m3, they will be clumped if adding more.
11. What are the common issues and remedies for pumping and finishing fiber-reinforced concrete?
Fiber-reinforced concrete can be easily pumped and completed, as long as the correct mix design is done before adding the fiber, and precautions are taken not to overflow the concrete surface. There is no guarantee that the fibers will not be visible on the surface of concrete. Although the same appearance of ordinary concrete can be obtained through appropriate technology and fiber selection.
12. What improper operation may lead to poor polypropylene mesh fiber dispersion?
Concrete and fiber types do not correspond. For example, the mortar can only use fiber of 6-12 mm in length. The quality of the fiber itself. If not doing electrostatic treatment, it will hinder the dispersion. Adding a small amount of water can reduce the amount of dispersion, prevent static electricity.
13. What advantages does Fiberego polypropylene fiber have over its fiber counterparts?
● Fiberego has strong financial chain support. For our long-term cooperation customers, we can guarantee that the price of the goods supplied to you will remain unchanged throughout the year when the annual capital fluctuation does not exceed 20%.
● The delivery cycle is short. We can deliver the goods one and a half months in advance if the supply is sufficient. About quality control, we own 36 years of industry history. With rich experience, we have plenty of time to improve the quality of our own services.
14. How to mix PP fiber?
Adding fibers in the middle of the sand and gravel, then adding water and mixing. The mixing time should be slightly longer than the mixing time of plain concrete by 30-60s to ensure that the fibers are evenly dispersed in the mixture.
15. How to clean up fibers on the concrete surface?
● Press the fibers into concrete with a defoaming roller just after pouring the concrete.
● After the curing period, seal the concrete surface with fire.
16. How to identify high-quality fibers for concrete?
● High-quality fibers should have good hydrophilicity and dispersibility.
● They do not contain impurities and moisture.
● The color is bright and white.
17. How do I choose the proper length and diameter of your fiber?
The longer and thinner the fiber, the better the reinforcement effect, but at the same time, the dispersion is worse. The generally recommended length is within 20MM. Welcome to leave a message, we will provide you with professional services.
18. How can macro fiber be considered equal since they are stronger than polypropylene fibers?
● Macro-polypropylene fibers, such as Fiberego macro fiber, have lower tensile strengths and Modulus of elasticities than steel fibers but will have a much higher fiber count across a potential crack. In effect, the total strength across a crack should be equivalent. This strength is also dependent on the ability of the fiber to bond to the concrete matrix itself.
● A very high tensile strength fiber that does not bond to concrete will not perform as a good fiber candidate. Fiberego macro fiber, through its unique ability to self-fibrillate, maximizes its tensile capacity through a high surface area, to which it bonds to the concrete, making it one of the premium macro-synthetics on the market.
19. How the temperature affects the fiber break strength in concrete？
● The temperature doesn’t affect the fiber strength. However, there will be freezing-thawing of concrete in the cold region in the crossing of winter and spring, which will affect the strength of concrete.
● Polypropylene fibers have little effect on the effects of freeze-thaw. The experiment proves that the alkali resistant glass fiber is to solve the influence of freezing and thawing of concrete.
20. How do I calculate an accurate polypropylene mesh fiber/macro synthetic fiber/polypropylene fiber dosage?
● Don’t worry. Our professional engineers will work with you to decide the exact dosage required for your specific application. At the same time, we will recommend the most suitable packaging form for you (our packaging includes water-soluble packaging bags and water-soluble packaging boxes of various specifications)
● You can directly throw the bags or boxes into the concrete mixer during construction.Check out the tools provided in our specification guides, including application guides with common-case design tables. You are always welcome to submit your project for review by our team.
21. How can I know that the polypropylene mesh fiber fibers are evenly distributed on my wall? Is there any way to verify?
After adding the fiber, take the same quality concrete from different parts of the concrete, wash out the fiber with a special method and measure the fiber content of each part. If the difference is not more than 10%, it can be determined that the fiber is evenly distributed in the concrete.
22. How do polypropylene fibers work in early-age concrete?
● The stress exceeds the strength of the concrete at a specific time.
● The growth of these micro shrinkage cracks is inhibited by mechanical blocking action of the polypropylene fibers. The internal support system of the polypropylene fibers inhibits the formation of plastic settlement cracks.
● The uniform distribution of fibers throughout the concrete discourages the development of large capillaries caused by bleed water migration to the surface. Polypropylene fibers lower permeability through the combination of plastic crack reduction and reduced bleeding characteristics.
23. How do polypropylene fibers work in hardened concrete?
● After the introduction of polypropylene fiber into the concrete, the ability to resist crushing force is greatly enhanced. When plain concrete is compressed, it will break and fail the first time it cracks. Polypropylene fibers specially made for concrete prevent the influence of crushing force by holding the concrete tightly together.
● When polypropylene fiber is used, it can provide abrasion resistance because the water-cement ratio of the surface will not be reduced due to variable bleeding. The water-cement ratio of the concrete surface is more constant.
● This improvement is due to the internal settlement support value of polypropylene fiber, which helps to uniformly bleed polypropylene fiber to reduce the amount of plastic cracking of concrete.
24. In which areas are polypropylene mesh fiber, macro synthetic fiber, and polypropylene fiber mostly used respectively?
● The limit is not absolute. polypropylene fiber is used for the exterior walls. polypropylene mesh fiber, macro synthetic fiber and steel fibers are mostly used for interior structure, water conservancy engineering, road and bridge engineering, etc.
● Steel fiber for structural construction. The factory floor is another application direction for steel fiber. The steel fiber is usually made into rows so that we can reduce the volume ratio, save your freight, and make it easy to disperse.
25. Will there be fibers on the surface?
Not if you use it in right dosage. For more detail, please let us know by sending us emails!
26. Will hollow fiber cost more?
The ductility of hollow is small. Technically, hollow fibers are not fully hollow. There are gaps inside and easy to absorb water. The strength is less than 200, with almost no strength.
27. Will I require to use a dry-shake hardener to cover the fibers?
● No. The fibers we produce and recommend are used regularly without any dry shake hardener.
● For more detail please contact your local Fiberego representatives.
28. Can I substitute your product with another kind of synthetic fiber?
There are risks doing this. Fiberego approved designs may not be compatible with other fibers in terms of type and length in regards to preventing cracks. Other fiber types may also make concrete more difficult to place and finish, which causes more visible fibers on the floor surface.
29. Can the length of the goods be customized? What is the default size ?
Yes. Our products can be customized according to your needs within a certain range, such as length, shape, etc.
30. Why does concrete crack?
It contains 3 parts.
● Temperature crack. It is caused by the excessive temperature difference between the inside and outside of the concrete.
● Shrinkage cracks. Influenced by air and humidity, the concrete panels lose too much water, then cracks occur. Coupled with the superposition of temperature stress and shrinkage, it poses an important threat to concrete cracks. So, it should be prevented as soon as possible and dealt with in time.
● Structural cracks. It is usually caused by the characteristics of long and thin panels, and its uneven deformation.
31. If I have special requirements for fiber quality, can you conduct experiments?
Our platform capacity is limited, but we can cooperate with other teams. Please contact us and feel free to let us know any of your issues.
32. Does melting point have any influence on how the fiber products works?
The influence of the different melting point of asphalt concrete on fiber usage can be neglected. The melting point of PESF is even higher than that of polypropylene fiber.
33. Is your PP fiber mono-filament?
Yes, we have mono-filament fiber which has excellent resistance to bending and fatigue. Its diameter is about 30μm.
34. During the project, in which link should I put the polypropylene fibers into the concrete?
● Fiber addition in concrete needs a strict addition process. Under normal circumstances, the mixing time after adding fiber and concrete should be increased from 10 to 20 seconds. The addition-adding link also requires special order.
● Gravel or sand → the fiber→ the stone or sand. In this way, we prevent the fibers is added to the surface directly. After 10-20 seconds the process of dry mix, you can carry on the wet mix.
35. When I was carrying on the experiment, your product agglomerated with concrete. What was the reason? How to solve it?
A combination of factors should be taken into consideration.
For example, the production process, the product itself, the water content exceeds the standard, etc.
The problem may occur in the while- process step. If you add the water-containing cement first, the fiber is more likely to be stick. But if you first add raw materials then conduct dry mixing adhesion, the problem will be solved.