Cellulose fiber in construction

Important construction fibers are: cellulose ether, methyl cellulose (MC), hydroxypropyl methyl cellulose (HPMC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), lignin fiber , Cellulose fiber.

Due to the characteristics of cellulose itself, such as natural hydrophilicity, excellent gripping force, huge fiber specific surface area, and high toughness and strength, etc., after being added to concrete, under the action of water soaking and external force, it forms A large number of evenly distributed fine fibers can effectively prevent the occurrence of cracks caused by plastic shrinkage, dry shrinkage and temperature changes of concrete, and significantly improve the mechanical properties of concrete.

Cellulose fibers make the cement hydrate more completely, significantly reduce the voids in the concrete, and make the concrete denser, thereby improving the frost resistance, water permeability, and chloride ion permeability of the concrete, and endowing the concrete with better durability.

(1) Anti-cracking effect on concrete

Cellulose fibers are three-dimensionally distributed in concrete, which can effectively reduce the stress concentration at the tip of micro-cracks, weaken or eliminate the tensile stress caused by shrinkage of concrete or mortar, and prevent the occurrence and expansion of micro-cracks.

(2) Improve the impermeability of concrete

The uniform distribution of cellulose fibers in concrete forms a supporting system, which hinders the surface water separation and the settlement of aggregates, reduces the bleeding of concrete, reduces the bleeding channels of concrete, and greatly reduces the porosity in concrete, so The impermeability of concrete is significantly improved.

(3) Improve the freeze-thaw resistance of concrete

Due to the presence of cellulose fibers in concrete, it can effectively reduce the concentration of tensile stress in concrete caused by multiple freeze-thaw cycles, and prevent the further expansion of micro-cracks. In addition, due to the improvement of concrete impermeability, it is also beneficial to improve its freeze-thaw resistance.

(4) Improve the impact resistance and toughness of concrete

Cellulose fibers help to absorb the function of concrete components when they are impacted, and due to the crack resistance effect of fibers, when the concrete is subjected to impact loads, the fibers can prevent the rapid expansion of internal cracks, so it can effectively enhance the impact resistance of concrete and toughness.

(5) Improvement of concrete durability

Due to the good crack resistance effect of cellulose fibers, the occurrence and development of cracks are greatly reduced, and the reduction of internal porosity slows down the corrosion and penetration of moisture in the external environment and chemical media, chloride salts, etc., due to the large number of cracks Reduced, the corrosion of the main reinforcement of the structure is reduced, so that the durability of concrete is greatly improved and enhanced.

(6) Improvement of high temperature resistance of concrete

In concrete, especially in high-strength concrete, cellulose fiber is added, because it contains a large number of uniformly distributed fiber monofilaments, which presents a three-dimensional random distribution and forms a three-dimensional network structure. When the internal temperature of the flame-baked concrete member rises to 165 When the temperature is above ℃, the fibers melt and form internally connected channels for strong high-pressure steam to escape from the interior of the concrete, so it can effectively avoid bursting in a fire environment and significantly improve the durability of concrete.

The anti-seepage and anti-crack fiber can enhance the strength and anti-seepage performance of concrete. The combination of fiber technology and concrete technology can develop steel fibers and synthetic fibers that can improve the performance of concrete and improve the quality of civil engineering. The former is suitable for dams, airports, high-speed Highway and other projects can play anti-cracking, anti-seepage, impact resistance and flexural properties, the latter can prevent early cracking of concrete, and protect the surface in the early stage of concrete material manufacturing. It has good effects on preventing coating cracking, improving water retention, improving production stability and construction suitability, increasing strength, and enhancing adhesion to the surface.

Fiber technology is widely used in asphalt roads, concrete, mortar, gypsum products, wood pulp sponge and other fields, road surfaces and parking lots in high-temperature and rainy areas; anti-skid surfaces of expressways, urban expressways, and arterial roads; bridge deck pavement, especially Steel bridge deck pavement; Alpine regions, preventing temperature shrinkage cracks; Highway heavy traffic sections, heavy load and overloaded vehicle sections; Intersections of urban roads, bus stations, freight yards, port terminals.