High-ductility self-recovery cement-based composite column

A self-restoring, cement-based technology, applied in the direction of columns, pier columns, pillars, etc., can solve the problems of low shear and flexural strength, poor seismic performance, high brittleness, etc., and achieve improved electrical conductivity, ductility and excellent seismic performance , enhance the binding effect

Inactive Publication Date: 2020-11-17
SOUTHEAST UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the high brittleness of the concrete material itself, low tensile, shear and flexural strength, and poor bonding performance with the steel pipe, it affects the integrity and stability of the CFST column to a certain extent, which is not conducive to the seismic resistance of the structure. , and it is difficult to repair after the earthquake
Existing concrete-filled steel tube columns have the defects of low ductility and poor seismic performance. Therefore, high-ductility fiber-reinforced concrete columns with steel tubes came into being
The ductility, integrity, anti-seismic and anti-cracking properties of steel pipe high ductility fiber reinforced concrete columns and the bonding performance of concrete and steel pipes have all been improved. However, in areas with frequent earthquakes, steel pipe high ductility fiber reinforced concrete columns need to be promptly repaired after cracking. and difficult to repair

Method used

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  • High-ductility self-recovery cement-based composite column
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  • High-ductility self-recovery cement-based composite column

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A high ductility self-healing cement-based composite column, including steel pipes and cement-based materials, the cement-based materials include cement mortar, SMA fiber and carbon black, wherein the cement mortar is cement, glass powder, quartz sand, fly ash, water, reducing Water agent, wherein, calculated according to the mixing ratio, 250 parts of cement, 25 parts of glass powder, 400 parts of quartz sand, 900 parts of fly ash, 330 parts of water, 6 parts of water reducing agent, 10 parts of carbon black, with cement and glass powder , quartz sand, fly ash, water, and water-reducing agent are uniformly mixed volume as the base, and the volume content of SMA fiber is 1.5%; among them, SMA fiber and cement are P·I 42.5R Portland cement; glass powder It is recycled glass powder milled for 24 hours, with a particle size of about 15 μm; the quartz sand is refined quartz sand; the fly ash is Class I fly ash; the water reducer is a polycarboxylic acid high-performance wate...

Embodiment 2

[0032] On the basis of Example 1, different from Example 1, 200 parts of Portland Type I cement, 20 parts of glass powder, 420 parts of refined quartz sand, 950 parts of Class I fly ash, 350 parts of laboratory tap water, 4 parts of polycarboxylate high-performance water reducer, 10 parts of conductive carbon black, the volume content of SMA fiber is 1%, the ratio of SMA fiber to carbon black is 64:10; the average fiber diameter is about 0.2mm, and the length is about It is 12mm; the average particle size of carbon black is 200nm.

[0033] The test under the same conditions as in Example 1 showed that the 28d tensile strength was 4.8 MPa, and the ultimate tensile strain was 0.23%. In its ultimate tensile strain stage, the stress is removed after cracking, and after standing for a period of time, most of the tiny cracks are closed, and the closing rate reaches more than 50%, and the width of the main cracks in the final stretching area is significantly reduced, as image 3 (b)...

Embodiment 3

[0035]On the basis of Example 1, different from Example 1, 200 parts of Portland Type I cement, 950 parts of Class I fly ash, 350 parts of laboratory tap water, 10 parts of conductive carbon black, the volume of SMA fiber mixed The amount is 1.5%, and the ratio of SMA fiber to carbon black is 96:10.

[0036] The test was carried out under the same conditions as in Example 1, the 28d tensile strength was 5.0 MPa, and the ultimate tensile strain was 0.37%. In its ultimate tensile strain stage, the stress is removed after cracking, and after standing for a period of time, most of its tiny cracks are closed, and the closing rate reaches more than 80%. The width of the main cracks in the final stretching area is obviously reduced and almost completely closed, showing an obvious cracking mode with many cracks, such as image 3 (c) shown. By comparing the change of resistivity after cracking and recovery, it is found that the resistivity after recovery is 75% lower than that after ...

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Abstract

The invention discloses a high-ductility self-recovery cement-based composite column, which comprises a steel pipe and a self-recovery cement-based material poured in the steel pipe, wherein the self-recovery cement-based material comprises cement mortar, SMA fibers and carbon black, and the mass ratio of the SMA fibers to the carbon black is 32:5-96:10. The high-ductility self-recovery cement-based composite column can bear large deformation and is excellent in ductility and anti-seismic property; and carbon black is doped into a matrix and is combined with conductive SMA fibers, so that theconductivity of the matrix is improved, and the cracking condition can be sensitively detected by analyzing the change of resistivity after the material is cracked and recovered.

Description

technical field [0001] The invention relates to a cement-based composite column, in particular to a high-ductility self-restoring cement-based composite column. Background technique [0002] With the development of building industrialization, steel pipe concrete columns have been widely used in large-scale civil engineering or high-rise civil buildings in China, and have achieved good economic and social benefits. However, due to the high brittleness of the concrete material itself, low tensile, shear and flexural strength, and poor bonding performance with the steel pipe, it affects the integrity and stability of the CFST column to a certain extent, which is not conducive to the seismic resistance of the structure. , and it is difficult to repair after the earthquake. The existing concrete-filled steel tube columns have the defects of low ductility and poor seismic performance. Therefore, high-ductility fiber-reinforced concrete columns with steel tubes came into being. T...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B28/04E04C3/34C04B111/94
CPCC04B28/04C04B2111/94E04C3/34C04B14/06C04B14/22C04B14/48C04B18/08C04B14/022C04B2103/302
Inventor 潘金龙蔡景明韩进生许荔
Owner SOUTHEAST UNIV
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