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A special admixture for water-reducing type steam curing shield tunnel segment concrete

A shield segment, steam-free curing technology, applied in the field of concrete admixtures, can solve the problems of unfavorable segment concrete air bubble discharge, concrete viscosity increase, affecting segment installation, etc., to reduce demoulding time and reduce porosity rate, and the effect of improving durability

Active Publication Date: 2020-06-02
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the domestic segment production industry is developing rapidly, but there are still the following problems: 1) most segments need to be cured by steam, which consumes a lot of energy; Affect the subsequent installation of segments
[0004] Among the existing patents, the Chinese patent CN 101007715A uses 25%-40% of slag, 40%-50% of fly ash, 15%-25% of silica fume, and 3%-6% of functional adjustment components to prepare shield segments with high resistance Permeable concrete admixture, the admixture of this patent is mainly used to improve the impermeability of the shield segment. When used, the admixture is relatively large, and the patent uses slag as a mineral admixture. After adding slag powder, Especially for S115 slag powder, the viscosity of concrete increases, which is not conducive to the discharge of air bubbles in segmented concrete

Method used

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  • A special admixture for water-reducing type steam curing shield tunnel segment concrete
  • A special admixture for water-reducing type steam curing shield tunnel segment concrete
  • A special admixture for water-reducing type steam curing shield tunnel segment concrete

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] When P.O42.5 cement is used for cement, C50 segment concrete is made with water-reducing non-steam curing shield segment concrete admixture.

[0031] 1) Preparation of special admixture for water-reducing non-steam curing shield segment concrete

[0032] Prepare water-reducing non-steam curing shield segment concrete admixture according to the ratio of each component in Table 1.

[0033] Table 1 The mass percent of each component of the admixture

[0034] Example Fly Ash Microbeads Silica fume early strength agent Defoamer 1 82％ 10％ 7％ 1％

[0035] Fly ash microbeads are global, continuous gradation distribution, ultrafine, solid, aluminosilicate fly ash microbeads, the water demand ratio is less than 90%, and the 28-day activity index is greater than 110%. The fly ash microbeads of this implementation select the "fine microbeads" product of Shenzhen Daote Technology Co., Ltd.

[0036] The specific surface area of ​​silica fume in the pres...

Embodiment 2

[0044] When P.O42.5 cement is used for cement, C55 segmental concrete is made with water-reducing non-steam curing shield segmental concrete admixture.

[0045] 1) Preparation of special admixture for water-reducing non-steam curing shield segment concrete

[0046] Prepare water-reducing non-steam curing shield segment concrete admixture according to the ratio of each component in Table 3.

[0047] Table 3 The mass percentage of each component of the admixture

[0048] Example Fly Ash Microbeads Silica fume early strength agent Defoamer 2 83％ 9％ 7％ 1％

[0049] Fly ash microbeads are global, continuous gradation distribution, ultrafine, solid, aluminosilicate fly ash microbeads, the water demand ratio is less than 90%, and the 28-day activity index is greater than 110%. The fly ash micro-beads of this embodiment select the "fine micro-beads" product of Shenzhen Daote Technology Co., Ltd.

[0050] The specific surface area of ​​silica fume in the ...

Embodiment 3

[0059] When the cement is P.II52.5 cement, use the special admixture for water-reducing non-steam curing shield segment concrete to make C50 segment concrete.

[0060] 1) Preparation of special admixture for water-reducing non-steam curing shield segment concrete

[0061] Prepare water-reducing non-steam curing shield segment concrete admixture according to the ratio of each component in Table 5.

[0062] Table 5 The mass percentage of each component of the admixture

[0063]

[0064]

[0065] Fly ash microbeads are global, continuous gradation distribution, ultrafine, solid, aluminosilicate fly ash microbeads, the water demand ratio is less than 90%, and the 28-day activity index is greater than 110%. The fly ash microbeads of this implementation select the "fine microbeads" product of Shenzhen Daote Technology Co., Ltd.

[0066] The specific surface area of ​​silica fume in the present embodiment is at 15000m 2 / kg~20000m 2 / kg range, the 28-day activity index is g...

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Abstract

The invention relates to an admixture special for water-reducing type autoclaving-free shield segment concrete. The admixture is prepared from the following components in parts by weight: 50 to 100 parts of coal ash microbeads, 5 to 30 parts of silicon ash, 1 to 10 parts of early strength agent and 0.1 to 2 parts of defoaming agent. Compared with the prior art, the special admixture disclosed by the invention has a certain water reducing function; by doping the admixture, the early strength of the shield segment concrete can be improved remarkably under the condition of normal maintenance, the demolding time is shortened, meanwhile long-term mechanical performance and durability are not influenced, the anti-seepage performance of the shield segment concrete is improved, the viscosity of the shield segment concrete is lowered, the surface bubble situation of a shield segment is improved, and the appearance of the shield segment is improved at a certain degree.

Description

technical field [0001] The invention relates to a concrete admixture, in particular to a water-reducing type special admixture for shield segment concrete without steam curing. Background technique [0002] With the rapid development of my country's urban construction, large-scale construction of subway projects is under way in my country's first-tier cities, and subway projects are also emerging in second- and third-tier cities. Domestic urban rail transit construction is showing a trend of rapid development. At present, most of the subway tunnels under construction in my country are constructed by the shield method. In the shield tunnel, the subway shield segment is the main structure of the tunnel, and the reinforced concrete shield segment is the most commonly used lining structure in China. According to the construction experience at home and abroad, the high-performance concrete used for the shield segment should meet the requirements such as water-cement ratio not gre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B24/12C04B28/04
CPCC04B28/04C04B40/0042C04B2201/50C04B2201/52C04B18/08C04B18/146C04B22/147C04B24/04C04B24/122C04B2103/302
Inventor 张雄张悦然王啸夫吴凯王浩任潘菲
Owner TONGJI UNIV
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