Cement concrete bridge deck structure is one of the widely used in highway construction in china. It has excellent properties of high strength, good durability, but the concrete as a kind of porous brittle material, its low tensile strength, poor toughness, easy to form cracks. Although in the process of construction engineering quality problems to take preventive measures, strict levels, or due to the impact of the construction environment, raw materials and other factors, resulting in bridge deck pavement due to early plastic shrinkage, dry shrinkage and temperature shrinkage stress caused by comprehensive bridge surface cracks.
The crack will accelerate the corrosion medium such as water, carbon dioxide and other substances through the penetration or diffusion way into concrete, concrete from corrosion, corrosion, freeze-thaw damage and other diseases, these diseases will seriously affect the reliability of reinforced concrete deck durability and structure. Therefore, in order to reduce early cracking of deck, we take the most direct and effective method for the new material is added to a building such as polyacrylonitrile fiber reinforced concrete, crack resistance and toughness of concrete, to prevent concrete early cracks effect.
Below we specifically look at the role of polyacrylonitrile fiber in concrete:
(1) polyacrylonitrile fiber mixed in concrete after mixing with three-dimensional random distribution, to form a three-dimensional random support network, it has dispersed shrinkage stress and increase the cohesiveness of concrete segregation, prevent concrete coarse aggregate, making it difficult to avoid water movement, water evaporates quickly, thereby reducing the cement paste plastic shrinkage cracking possibility, inhibit the emergence and development of micro cracks in concrete.
(2) the tensile strength and elastic modulus of polyacrylonitrile fiber has higher, the elastic modulus of concrete is. Because the cement base polyacrylonitrile fiber elastic modulus is higher than the early plastic state, and the diameter of the fiber is fine in 3D staggered random distribution in concrete and reinforced concrete matrix toughness effectively, helps to weaken the plastic shrinkage of concrete, when the fiber contraction energy dispersion to tens of thousands of lm3 has high tensile strength and the relatively high modulus of elasticity, improve concrete anti cracking ability of deformation, thereby inhibiting the emergence and development of micro cracks.
(3) using polyacrylonitrile fiber significantly reduce concrete shrinkage deformation. With the fiber in 3D irregular distribution, when the crack development and fiber intersection, fiber has certain stress transfer function, can offset some or all of the stress; therefore it has obvious effect of crack resistance, thereby increasing the resistance to cracking of plastic tensile strength.
Has the anti shrinkage and cracking resistance, breaking good performance of polyacrylonitrile fiber mixed concrete, tensile effect is very significant, for concrete strength and toughness is insufficient. To effectively prevent early cracking of the bridge, so as to ensure the construction quality of the whole bridge, prolong the service life of the bridge, and the community praise of people. So many people think the polyacrylonitrile fiber has unique advantages in improving the anti cracking performance of concrete, which has good economic and social benefits, it is worthy of popularization and application. Strong brand XDJ polyacrylonitrile fiber, is a kind of special cement concrete material reinforced with fiber Changzhou leade alone to develop new Mstar Technology Ltd. More robust licensing XDJ polyacrylonitrile fiber, welcome to contact us!