Abstract: according to the requirements of the bridge deck pavement of a highway bridge design, the 100mm thick C50 waterproof concrete were micro silicon polypropylene fiber concrete mix proportion design, performance test and bridge deck pavement construction measures of. Result display. The polypropylene fiber and micro silica fume shrinkage compensating concrete with excellent crack resistance, impermeability, wear resistance, impact resistance, fatigue resistance etc. performance.
Ordinary concrete bridge deck pavement due to the thickness of the design is thin (80~150mm), the brittle. In the driving process, the bending load, impact fatigue load, temperature and humidity deformation and other factors, which can easily lead to the ordinary concrete bridge deck pavement cracking, damage, waterproof failure, etc.. Polypropylene fiber can enhance the anti fatigue, impact resistance, wear resistance and crack resistance of polypropylene fiber reinforced concrete. As well as improve the toughness and the permeability, it can effectively prevent the concrete internal and surface cracks, or delay the emergence of cracks, it is used for bridge deck pavement of a relatively ideal material. Therefore, the bridge deck pavement concrete materials design using polypropylene fiber reinforced concrete. While adding silica fume, to compensate for the shrinkage, extend the spacing of deck joints. Further improve the concrete crack, seepage control ability.
1 Experiment
1.1 raw materials
The main raw materials are: 1. The cement used in the production of Qinhuangdao's shallow cement factory is 42.5 ordinary portland cement, the strength is: 3D anti 5.9MPa, 28.8MPa, 28d,, 8.8MPa, 54.8MPa. The admixture of Shenyang rich FL water reducer (powder). The coarse aggregate is a long gem, 5~20mm continuous gradation. The fine aggregate is small gudonghe in coarse river sand, fineness modulus of 2.88. The first day in Ningxia with expansive agent construction materials research of micro silicon powder production. The fiber using Hongrui Lai (Beijing) Technology Co., Ltd. is the production of mesh polypropylene fibre, the main physical and mechanical performance parameters are: density 0.91g/cm3, melting temperature of 165 DEG C, ignition temperature of 590 DEG, non absorbent and toxicity of airlines tensile strength of 560 to 770MPa. tensile limit of 15%, elastic modulus of 3500 MPa, fiber length of 19mm.
1.2 experimental concrete mix ratio
Design of concrete requirements: About 50mm of concrete mixture slump, cohesive and water retention of meet the construction requirements; concrete strength grade C50. Preparation strength 64.1MPa, anti permeability level W22 above. According to the design requirements, a large number of experiments were carried out in Table 2 of the 1 complexes to carry out a further contrast experiment.
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1.3 experimental method
The concrete compressive strength test was carried out by using the size of 150mmx150mmx150mm of the cubic concrete specimens. According to the test procedure of JTJ053 ~ 94 highway engineering cement concrete.
Concrete anti permeability strength test using top surface diameter 175mm, bottom diameter of 185mm, height is 150mm cone concrete specimens and in accordance with the literature [1] test. Concrete strength test of concrete specimens, using the size of 150mmx150mmx150mm, according to the literature [1]. The diameter of the concrete is 150mm. A round cake shaped concrete specimen with a thickness of [2] was carried out in accordance with the recommendation of the ACl544 Committee. Concrete flexural strength test using the size of 150mmx150mm x 550mm of concrete specimens, according to the literature [1] in Italy Controis company production of 50 C0066/S01 type universal pressure testing machine.
2 experimental results and analysis
The test results of the concrete performance are shown in table 2. From the concrete mixture slump, No. 2 and No. 1 with the mix ratio compared to. After per cubic meter of concrete mixed with 20kg of micro silica and 0.9kg dosage of polypropylene fiber, due to the formation of "bearing" effect of polypropylene fiber and micro silica rapid hydration reaction of ettringite, slump of concrete mixture to reduce large (about 100 mm). From concrete strength and resistance to penetration
In view of the results, the design requirements of the two kinds of the ratio of to the C50 and the anti permeability of the W22 were achieved. In bending strength, impact toughness and wear resistance and other mechanical properties, better than 2.
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In the concrete incorporation expansive agent and polypropylene fiber: the amount of micro silica fume, and can compensate the concrete shrinkage, improve the compactness of concrete, so as to play the role of anti cracking and improve the impermeability of concrete. Polypropylene fiber can improve the anti plastic shrinkage and drying shrinkage cracking of concrete, and improve the anti impact toughness, anti permeability, frost resistance and abrasion resistance of concrete, which is very useful for the durability of bridge deck pavement. Of course, micro silicon powder and polypropylene fiber in concrete crack resistance mechanism is completely different: micro silicon powder is mainly by chemical reaction generated aft crystal expansion. The expansion pressure generated by the constraint should be force to counteract the tensile stress due to shrinkage of part; and polypropylene fiber is produced by a large number of scattered in the concrete matrix micro fiber, concrete shrinkage tensile stress is dispersed, inhibited the propagation of cracks in back.
3 construction
The concrete construction of bridge deck pavement of a bridge is carried out by using 2. Bridge deck pavement construction process: Deck chiseling and cleaning clean ---- > mesh reinforcement installation, support ---- > deck wetness, installation elevation control track ---- > micro silicon polypropylene fiber concrete pouring ---- > Import vibration Liang Zhendao, float facing ---- > coverage maintenance ---- > cut hair. Concrete pouring construction of the full range of continuous operation.
In the construction, the following measures are adopted to ensure the quality of bridge deck pavement. Deck pavement, bridge deck chiseling and fully clean, otherwise easily lead to the hollowing of bridge deck pavement. Concrete pouring
