Cellulose fiber in concrete
Writer： admin Time：2023-11-01 16:10 Browse：
Due to the characteristics of cellulose fiber itself, such as natural hydrophilicity, excellent gripping force, huge fiber specific surface area, high toughness and strength, after being added to concrete, a large number of uniformly distributed fine fibers are formed under the action of water immersion and external force, which can effectively prevent the occurrence of cracks caused by plastic shrinkage, dry shrinkage and temperature change of concrete.
2、 Obviously improve the mechanical properties of concrete
1. Crack resistance to concrete
Cellulose fibers are three-dimensional distributed in concrete, which can effectively reduce the stress concentration at the tip of micro cracks, weaken or eliminate the tensile stress caused by dry shrinkage of concrete or mortar, and prevent the occurrence and expansion of micro cracks.
2. Improvement of impermeability of concrete
The uniform distribution of cellulose fiber in concrete forms a support system, hinders the surface water precipitation and aggregate settlement, reduces the bleeding of concrete, reduces the bleeding channel of concrete, and greatly reduces the porosity in concrete. Therefore, the impermeability of concrete is significantly improved.
3. Improvement of freeze-thaw resistance of concrete
The existence of cellulose fiber in concrete can effectively reduce the tensile stress concentration in concrete caused by multiple freeze-thaw cycles and prevent the further expansion of microcracks. In addition, the improvement of concrete impermeability is certainly conducive to improve its freeze-thaw resistance.
4. Improvement of impact resistance and toughness of concrete
Cellulose fiber helps to absorb the function of concrete components under impact. Due to the crack resistance effect of fiber, fiber can prevent the rapid expansion of internal cracks when concrete is subjected to impact load, so it can effectively enhance the impact resistance and toughness of concrete.
5. Improvement of concrete durability
Due to the good crack prevention effect of cellulose fiber, the occurrence and development of cracks are greatly reduced, and the internal porosity is reduced, which slows down the erosion and penetration of water corrosivity, chemical medium and chlorine salt in the external environment. Due to the large reduction of cracks, the channel of corrosion to the main reinforcement of the structure is reduced, so as to greatly improve and improve the durability of concrete.
6. Improvement of high temperature resistance of concrete
Cellulose fiber is added to concrete, especially high-strength concrete. Because it contains a large number of evenly distributed fiber monofilaments, it presents three-dimensional random distribution and forms a three-dimensional network structure. When the internal temperature of the flame baked concrete component rises to more than 165 ℃, the fiber melts and forms internally connected channels for strong and high-pressure steam to escape from the concrete, Therefore, it can effectively avoid bursting in fire environment.
3、 Obviously improve the durability of concrete
Cellulose fiber can make cement hydration more complete, significantly reduce the void of concrete and make concrete more dense, so as to improve the frost resistance, water permeability and chloride ion permeability of concrete and give concrete better durability.
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