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Low-shrinkage low-creep concrete composite additive suitable for early-age prestress tensioning

A composite additive and prestressing technology, which is applied in the field of low shrinkage and low creep concrete composite additives and functional additive materials for building concrete. It can solve problems such as easy cracking, water seepage, tension creep, and complex stress, and achieve enhanced anti-settling ability , improve the compactness, ease the effect of stress concentration

Active Publication Date: 2021-01-08
湖南固特邦土木科技发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Aiming at the defects of complex stress, easy cracking and water seepage in the prestressed tensioned concrete structure in the prior art, the purpose of the present invention is to provide a low-shrinkage and low-creep concrete composite additive suitable for early-age prestressed tensioning, The concrete added with this composite additive can improve the bonding performance of the new and old concrete joint surface, reduce the cracking risk of the old and new concrete interface, and improve the cracking resistance of the concrete; by promoting the formation of a large number of ettringite crystals during the early hydration process of cement, it can improve the performance of concrete. Early strength, while compensating the shrinkage of concrete, reducing the creep shrinkage of concrete, solving the problem of large early tension and creep of concrete, greatly improving the quality and durability of bridges

Method used

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  • Low-shrinkage low-creep concrete composite additive suitable for early-age prestress tensioning
  • Low-shrinkage low-creep concrete composite additive suitable for early-age prestress tensioning

Examples

Experimental program
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Effect test

Embodiment 1

[0018] Example 1: Preparation of low-shrinkage and low-creep concrete composite additives suitable for early-age prestressed tension: 80 parts of anhydrous calcium sulfoaluminate clinker (80% content of anhydrous calcium sulfoaluminate), 5 parts of calcium sulfate 10 parts of silica fume (particle size 0.2 μm), 1 part of lithium carbonate, 1 part of triisopropanolamine, 0.1 part of anti-settling agent (D-glucose:D-galactose=4:6), styrene-butylene Diene copolymer (AXILAT PSB 150 from Hexion, USA) 3 parts, mixed and ground to a specific surface area of ​​2000cm 2 / g of powder.

[0019] Preparation of C60 low shrinkage and low creep wet joint concrete: P·O52.5 ordinary portland cement 280kg / m 3 , Class I fly ash 65 kg / m 3 、S95 mineral powder 65 kg / m 3 , Low shrinkage and low creep concrete composite additive suitable for early prestressed tension 80kg / m 3 , medium sand 720kg / m 3 , 4.75~9.5mm gravel 226kg / m 3 , 9.5-20mm gravel 903kg / m 3 , slow-release polycarboxylate superp...

Embodiment 2

[0020] Example 2: Preparation of low-shrinkage and low-creep concrete composite additives suitable for early-age prestressed tension: 60 parts of anhydrous calcium sulfoaluminate clinker (80% content of anhydrous calcium sulfoaluminate), 20 parts of calcium sulfate 10 parts of silica fume (particle size 0.2 μm), 2 parts of lithium carbonate, 3 parts of triisopropanolamine, 0.1 part of anti-settling agent (D-glucose:D-galactose=6:4), styrene-butylene Diene copolymer (AXILAT PSB 150 from Hexion, USA) 5 parts, mixed and ground to a specific surface area of ​​2000cm 2 / g of powder.

[0021] Preparation of C60 low shrinkage and low creep wet joint concrete: P·O52.5 ordinary portland cement 280kg / m 3 , Class I fly ash 65 kg / m 3 、S95 mineral powder 65 kg / m 3 , Low shrinkage and low creep concrete composite additive suitable for early prestressed tension 80kg / m 3 , medium sand 720kg / m 3 , 4.75-9.5mm gravel 226kg / m 3 , 9.5~20mm gravel 903kg / m 3 , slow-release polycarboxylate super...

Embodiment 3

[0022] Example 3: Preparation of low-shrinkage and low-creep concrete composite additives suitable for early-age prestressed tension: 70 parts of anhydrous calcium sulfoaluminate clinker (content of anhydrous calcium sulfoaluminate 70%), 10 parts of calcium sulfate 12 parts of silica fume (particle size 0.1 μm), 1 part of lithium carbonate, 2 parts of triisopropanolamine, 0.2 parts of anti-sedimentation agent (D-glucose:D-galactose=4:6), styrene-butylene 5 parts of diene copolymer (AXILAT PSB 150 from Hexion, USA), mixed and ground to a specific surface area of ​​2200cm 2 / g of powder.

[0023] Preparation of C60 low shrinkage and low creep wet joint concrete: P·O52.5 ordinary portland cement 280kg / m 3 , Class I fly ash 65 kg / m 3 、S95 mineral powder 65 kg / m 3 , Low shrinkage and low creep concrete composite additive suitable for early prestressed tension 80kg / m 3 , medium sand 720kg / m 3 , 4.75-9.5mm gravel 226kg / m 3 , 9.5~20mm gravel 903kg / m 3 , slow-release polycarboxy...

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Abstract

The invention discloses a low-shrinkage low-creep concrete composite additive suitable for early-age prestress tensioning. The composite additive is composed of anhydrous calcium sulfoaluminate clinker, calcium sulfate, silica fume, lithium carbonate, a styrene polymer, triisopropanolamine, an anti-settling agent and the like, is used in concrete taking ordinary Portland cement as a cementing material, and provides ettringite crystals through hydration reaction of anhydrous calcium sulfoaluminate and calcium sulfate. The forming speed of ettringite in a hydration product is increased by utilizing the seed crystal effect of silica fume and the early strength effect of lithium carbonate and triisopropanolamine, the purposes of micro-expansion, early strength, low shrinkage and low creep areachieved, meanwhile, the workability of concrete is improved through an anti-settling agent, and the later strength of silica fume is improved through a volcanic ash reaction; the concrete added withthe composite additive has the characteristics of early strength, micro-expansion and low creep, is suitable for concrete early-age prestress tensioning engineering, saves time and shortens the construction period.

Description

technical field [0001] The invention relates to a building concrete functional additive material, in particular to a low-shrinkage and low-creep concrete composite additive suitable for early-age prestressed tension, and belongs to the technical field of new building materials. Background technique [0002] In the engineering application of post-tensioned prestressed concrete structures, the problem of cracks in prestressed concrete before and after tensioning is often encountered. When the concrete structure is working with cracks, the durability of the engineering structure and the structural performance will be affected by it. Therefore, whether it is the construction process or the use stage, the generation of cracks is a problem that deserves special attention. For prestressed concrete structures, the crack control is quite strict. Although the cracks generated before tension may be closed after tension, cracks generated before tension will always have an adverse effec...

Claims

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Application Information

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IPC IPC(8): C04B24/26C04B24/10C04B28/04
CPCC04B28/04C04B40/0039C04B2103/0082C04B2103/60C04B2103/601C04B2103/61C04B2103/65C04B22/142C04B22/143C04B22/06C04B22/10C04B24/122C04B24/10C04B24/2676C04B18/08C04B18/141C04B14/06C04B14/02C04B2103/302
Inventor 单韧李军胡铁刚尹明韦庆
Owner 湖南固特邦土木科技发展有限公司
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