A kind of low-shrinkage self-compacting concrete for steel shell immersed tube, its preparation method and application

A technology of self-compacting concrete and low shrinkage, which is applied in artificial islands, reinforced molding, and infrastructure engineering, etc. It can solve the problems of large amount of cementitious materials, large concrete shrinkage, and poor volume stability, so as to reduce economic costs and temperature Effect of shrinkage, improvement of filling and compactness

Active Publication Date: 2020-04-14
CCCC FOURTH HARBOR ENG INST +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Traditional self-compacting concrete has a large amount of cementitious material, high sand rate, large shrinkage of concrete, and poor volume stability

Method used

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  • A kind of low-shrinkage self-compacting concrete for steel shell immersed tube, its preparation method and application
  • A kind of low-shrinkage self-compacting concrete for steel shell immersed tube, its preparation method and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] A method for preparing low-shrinkage self-compacting concrete for steel-shell immersed tubes, comprising the following steps:

[0053] 1) Ingredients according to the following ratio: P·II 42.5 Portland cement cement 250kg / m 3 , aluminum stabilizer compacting agent 180kg / m 3 , mineral powder 60kg / m 3 , limestone powder 30kg / m 3 , river sand 800kg / m 3 , gravel 867kg / m 3 , water 176.8kg / m 3 , superplasticizer 5kg / m 3 . Among them, the aluminum stabilizing and compacting agent is composed of fly ash and metakaolin in a mass ratio of 9:1. Fly ash is Class I original fly ash, Al in fly ash 2 o 3 The content is not less than 25%. Metakaolin is made from kaolin calcined at 650-800°C for 2-4 hours and then ground, with a specific surface area of ​​≥10,000m 2 / kg, Al in metakaolin 2 o 3 The content is not less than 40%.

[0054] 2) For stirring, a non-vertical shaft forced mixer is used, and the stirring time is 150s.

[0055] 3) 10 minutes after the mixing is com...

Embodiment 2

[0068] A method for preparing low-shrinkage self-compacting concrete for steel-shell immersed tubes, comprising the following steps:

[0069] 1) Ingredients according to the following ratio: P·II 42.5 Portland cement 260kg / m 3 , aluminum stabilizer compacting agent 160kg / m 3 , mineral powder 70kg / m 3 , limestone powder 25kg / m 3 , river sand 833kg / m 3 , gravel 833kg / m 3 , water 168.3kg / m 3 , water reducer 6.2kg / m 3 . Among them, it is composed of fly ash and metakaolin at a mass ratio of 9:1. Fly ash is Class I undisturbed fly ash.

[0070] 2) For stirring, a non-vertical shaft forced mixer is used, and the stirring time is 180s.

[0071] 3) After the mixing is completed for 5 minutes, the concrete output performance test is carried out. The indicators after the test are as follows:

[0072] Concrete mixture slump spread 620mm;

[0073] The outflow time of the concrete mixture V-shaped funnel is 11.5s;

[0074] Concrete Mixture L-type Instrument Test H 2 / H 1 valu...

Embodiment 3

[0084] A method for preparing low-shrinkage self-compacting concrete for steel-shell immersed tubes, comprising the following steps:

[0085] 1) Ingredients according to the following ratio: P·II 42.5 Portland cement cement 245kg / m 3 , aluminum stabilizer compacting agent 147kg / m 3 , mineral powder 49kg / m 3 , limestone powder 49kg / m 3 , river sand 933kg / m 3 , gravel 764kg / m 3 , water 156.8kg / m 3 , water reducer 6.5kg / m 3 . Among them, the aluminum stabilizing and compacting agent is composed of fly ash and metakaolin in a mass ratio of 9:1. The fly ash is Class I original fly ash.

[0086] 2) For stirring, a non-vertical shaft forced mixer is used, and the stirring time is 120s.

[0087] 3) 10 minutes after the mixing is completed, the performance of the concrete is tested, and the indicators of the tested concrete are as follows:

[0088] Concrete mixture slump spread 640mm;

[0089] The outflow time of the concrete mixture V-shaped funnel is 13.5s;

[0090] Concr...

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Abstract

Low-shrinkage self-compacting concrete used for steel-shell immersed tubes is disclosed. Raw materials of the concrete include cement, an aluminum stabilizing compacting agent, ore powder, limestone powder, river sand, broken stone, water and a water reducing agent. According to performance control indexes of a mixture of the concrete, the slump extension is 600-700 mm, V-shaped funnel efflux time is 5-15 s, the H2 / H1 value tested by an L-shaped instrument is not less than 0.9, a [delta]h value tested by a U-shaped instrument is not more than 30 mm, the unit weight is 2300-2400 kg / m<3>, and the gas content is not more than 4%. The concrete has good fluidity, fallibility and segregation resistance. Compared with traditional self-compacting concrete, the low-shrinkage self-compacting concrete has a low gel material using amount and low shrinkage, has good adaptability to steel-shell immersed tube structures, has a strength grade of C50, and is suitable for use as self-compacting concrete having good working properties, mechanical properties and volume stability for steel-shell immersed tunnels.

Description

technical field [0001] The invention belongs to the technical field of concrete, in particular to the technical field of self-compacting concrete. Background technique [0002] From the structural point of view, immersed tube tunnels mainly include reinforced concrete immersed tubes and steel shell concrete immersed tubes. The steel shell concrete immersed tube joint adopts the structural form of two-layer steel shell filled with concrete, and the pipe joint is composed of multiple cells. figure 1 Shown is a schematic diagram of steel shell concrete immersed tube joints, figure 2 Shown is a schematic diagram of the concrete pouring of the pipe section grid. Compared with reinforced concrete immersed tubes, steel shell concrete immersed tubes have the following advantages: lower cost, more convenient construction, shorter construction period, relatively smaller structure scale, stronger bearing capacity, better anti-settlement and seismic adaptability, less There are crac...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B28/04E02D29/073B28B21/56C04B111/56C04B111/74
CPCB28B21/56C04B28/04C04B2111/00146C04B2111/00706C04B2111/0075C04B2111/56C04B2111/74C04B2201/50E02D29/073E02D2300/002C04B18/08C04B14/106C04B18/141C04B14/28C04B14/06C04B14/02C04B2103/302
Inventor 王胜年吕卫清熊建波曾俊杰吕黄范志宏刘行
Owner CCCC FOURTH HARBOR ENG INST
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