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C30 self-compaction microexpanded concrete-filled steel tube and preparation method thereof

A technology of concrete-filled steel tube and micro-expansion, which is applied in the field of building materials, and can solve problems such as high water-binder ratio, affecting the service characteristics of steel tube concrete, and changing the interfacial tension of slurry

Active Publication Date: 2015-11-25
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Relatively speaking, the quality of cementitious materials in C30 concrete is less, and the cohesiveness of freshly mixed concrete is poor. It is difficult to achieve the high fluidity requirements of self-compacting concrete in order to completely wrap the aggregate in the slurry.
In practice, viscosifying components are usually introduced to improve the water retention by increasing the viscosity of cement paste, but the addition of viscosifying components changes the interfacial tension of the slurry, which brings additional air-entraining effect, which will further increase the air content of concrete. The increase of , affects the service characteristics of CFST
At the same time, steel pipe self-compacting concrete has a larger amount of cementitious material, sand rate, and water-binder ratio than ordinary concrete, and a smaller amount of coarse aggregate and particle size, which is prone to large temperature shrinkage and self-shrinkage, resulting in a gap between the steel pipe and the core concrete. "Debonding", affecting the synergy of the structure and shortening the service life
Common expansion agents are added to compensate for concrete shrinkage. Since the steel tube core concrete is in a moisture-proof and sealed environment, the water supply in the later period is insufficient. The expansion rate of commercially available expansion agents is too fast in the early stage, and the stability is poor. The problem of uncontrollable expansion behavior, it is difficult to match the requirements of the coordinated development of strength and expansion, and the bearing capacity of the deteriorated structure

Method used

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  • C30 self-compaction microexpanded concrete-filled steel tube and preparation method thereof
  • C30 self-compaction microexpanded concrete-filled steel tube and preparation method thereof
  • C30 self-compaction microexpanded concrete-filled steel tube and preparation method thereof

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preparation example Construction

[0043] In embodiment 2~5, the preparation method of described viscosity-increasing and plastic-retaining hyperdispersive admixture comprises the following steps:

[0044] 1) Using methallyl alcohol, ammonia water and propylene oxide as raw materials, sodium methallylate or potassium methallylate as a catalyst, under the conditions of a pressure of 0.10-0.40MPaG and a temperature of 50-150°C , reacted for 3 to 7 hours to prepare a mixture of methallyl alcohol polyoxypropylene ether and triisopropanolamine, the molar ratio of the methallyl alcohol, ammonia and propylene oxide was 1:(0.2 to 0.5) : (5.0~78.0), the consumption of catalyst is 0.10~0.60% of methallyl alcohol quality;

[0045] 2) Take the mixture of methallyl alcohol polyoxypropylene ether and triisopropanolamine prepared in step 1), sodium acrylate sulfonate, methacrylate and water as raw materials, add the mixture with reflux condenser, thermometer and In the three-necked flask of the dropping funnel, heat up to 60...

Embodiment 1

[0049] In embodiment 1, the preparation method of thickening and plastic-retaining ultra-dispersion admixture is roughly the same as embodiment 2~5, and difference is: 1) the mol ratio of methallyl alcohol, ammoniacal liquor and propylene oxide is 1:0.4: 20. The amount of catalyst used is 0.4% of the mass of methallyl alcohol, the reaction pressure is 0.30MPaG, the temperature is 105°C, and the time is 5h; 2) the reaction between methallyl alcohol polyoxypropylene ether and triisopropanolamine Mixture 86%, sodium acrylate sulfonate 3%, methacrylate 8%, water 3%; 3) The molar ratio of methacrylic acid and polypropylene glycol monomethyl ether is 1.18:1, dipropylene glycol monobutyl ether and maleic anhydride The molar ratio is 1.5:1, the reaction temperature is 120°C, and the time is 4h; 4) Polypropylene glycol monomethyl ether methacrylate monomer 82%, diethylene glycol dipropylene glycol monobutyl ether monomer 3%, methyl 8% acrylic acid, 3% dimethylaminoethanol, 4% sodium me...

Embodiment 2

[0068] A C30 self-compacting micro-expansion concrete-filled steel tube is applied to prepare upper and lower concrete-filled steel tube chords of a concrete-filled steel tube truss bridge. The preparation method comprises the following steps:

[0069] 1) take each raw material by the proportioning described in table 3;

[0070] 2) The internal curing material is pre-absorbed. Put the internal curing material in water to absorb water at a mass ratio of 1:15. The water absorption time is 2 to 3 hours, and stir evenly;

[0071] 3) Put the weighed ordinary Portland cement, fly ash, composite expansion agent, crushed stone and river sand into the concrete mixer for dry mixing, and in the process of dry mixing, the weighed micron modified absorbent cotton cellulose Add it into the mixer, fully dry mix it evenly (2~5min), and get the dry mix; mix the pre-absorbed internal curing material with the viscosity-enhancing plastic super-dispersion additive and water, and then put it in the...

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Abstract

The invention discloses a C30 self-compaction microexpanded concrete-filled steel tube and belongs to the field of building materials. The C30 self-compaction microexpanded concrete-filled steel tube is prepared by taking cement, coal ash, composite expansion agents, gravel, river sand, tackifying plasticity-maintaining ultra-dispersed additive, internal maintaining materials, micro-grade modified degreasing cotton cellulose and water as raw materials. The number of binding materials adopted in the C30 self-compaction microexpanded concrete-filled steel tube is small, and the C30 self-compaction microexpanded concrete-filled steel tube has the advantages of being good in self-compaction performance, low in gas content and high in durability, being slightly expanded and the like, is suitable for compact pouring of intensely reinforced large-pipe-diameter thin-wall steel tube concrete-filled steel tube underwater piles with complex shapes and a small section size, string tube pumping pouring of upper and lower concrete-filled steel tubes of concrete-filled steel tube truss bridges and high-throwing vibration-free pouring of concrete-filled steel tube pier studs. The problem of disengaging of the concrete-filled steel tube can be effectively solved, and wide application prospects are achieved.

Description

technical field [0001] The invention belongs to the field of building materials, and in particular relates to a C30 self-compacting micro-expansion steel pipe concrete and a preparation method thereof. Background technique [0002] C30 self-compacting micro-expansion concrete-filled steel tubes are mainly used in large-diameter thin-walled concrete-filled steel tube underwater piles, upper and lower concrete-filled steel tube chords of concrete-filled steel tube truss bridges, and concrete-filled steel tube piers. Among them, concrete-filled steel pipe underwater piles are difficult to pour due to the dense reinforcement and large pouring depth, so the concrete-filled steel pipe concrete is required to have good fluidity, cohesion, low air content, and micro-expansion. If the performance of the concrete fails to meet the design and construction requirements, it is easy to cause problems such as broken piles, insufficient filling and voiding. Concrete-filled steel tube pier ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B28/04C04B18/08C04B14/02C04B14/06C04B22/06C04B22/14
CPCY02W30/91
Inventor 丁庆军牟廷敏李超漆春生范碧琨洪斌刘小清王发洲胡曙光何良玉
Owner WUHAN UNIV OF TECH
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