The Experimental Research On Durability Of The High Strength Cellulose Fiber Concrete

The concrete was the most amount of building material in the project, also was the most main structural material. The reinforced concrete structure has become the most widespread structure in the world. But because of low design standard, construction quality, bad management and so on, Ageing and inferior of concrete happened in many hydraulic project. The durability research on hydraulic engineering concrete must been carryed out in order to enhance the service life of the hydraulic engineering structures.The cellulose fiber concrete is used in project form south to north at first in order to enhance durability of the concrete of aqueduct . The cellulose fiber is new generation of high performance fiber in USA. The structure of cellulose fiber is different from the natural lignocellulosic and synthetic fiber. There are many advantages of the cellulose fiber. For example, natural hydrophilicity, the unique structure of cavity, immense surface. The cellulose fiber can improve the anti-cracking performance.and can improve the anti-permeability and frost thawing resistance.The experimental research on application technology of the cellulose fiber concrete was carried on. The physical and mechanical properties of the cellulose fiber concrete were determined. The experiment include in fundamental mechanical test, flexural toughness test, flexural impact test , uniaxial tensile test, permeability test , freezing and thawing test.The flexural toughness and flexural impact experiment of the cellulose fiber concrete with different fiber content were carried on in the paper. The flexural toughness index was analyzed with the fiber content. The mathematical statistics method was introduced in order to systematical analysis the data of flexural impact experiment of the cellulose fiber concrete. And many toughness evaluation methods were used in order to calculation the toughness index. The result demonstrates that the toughness index of fiber concrete was improved and the deformability was improved.The uniaxial tensile test of the cellulose fiber were determined.and the cellulose fiber concrete stress - deformation curve was obtined, the tensile characteristics of fiber reinforced concrete value was obtined. The experimental results show that: with the content of cellulose fiber increacing, the fiber concrete tensile strength, the ultimate tensile strain and the fracture energy were increased. The permeability experiment of the cellulose fiber concrete with different fiber content was carried on in the paper. And the relationship between the permeability coefficient of concrete and the fiber content was researched. The main factor of influencing the permeability coefficient of concrete was analyzed. The relationship between the frost resistance of concrete and the fiber content was researched though freezing and thawing experiment. The mechanism of frost resistance of the cellulose fiber The concrete was investigate. These experiments can provide the basis for cellulose fiber application in hydraulic engineering.whole process of material or component from grown-in defects to forming macro cracks,even fracture, was researched in damage theory. And the constitutive relation of damaged material was established. The failure mechanism of material was explained. The evolution process of damaged material was established. The damage degree of component was calculated. The residual life of component was estimated. The model parameters of the cellulose fiber concrete damage mechanics model were obtained though uniaxial tensile test in this paper. The damage degree of component was calculated in freeze-thaw cycles. The result show that the damage mechanics model is anastomosis with the test results.