CN108658536B - Fiber-reinforced cement-based material and preparation method thereof - Google Patents
Fiber-reinforced cement-based material and preparation method thereof Download PDFInfo
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- CN108658536B CN108658536B CN201810500926.5A CN201810500926A CN108658536B CN 108658536 B CN108658536 B CN 108658536B CN 201810500926 A CN201810500926 A CN 201810500926A CN 108658536 B CN108658536 B CN 108658536B
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- based material
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/20—Resistance against chemical, physical or biological attack
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/90—Electrical properties
- C04B2111/92—Electrically insulating materials
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
Abstract
The invention discloses a fiber reinforced cement-based material and a preparation method thereof. The fiber reinforced cement-based material comprises the following components in percentage by weight: 30-32% of cement, 10-13% of fly ash, 10-16% of coarse sand, 25-33% of fine sand, 4-6% of silica fume, 8-9% of water and 1-1.5% of a water reducing agent, wherein the sum of the components is 100%; the fiber reinforced cement-based material also comprises steel fibers and basalt fibers, wherein the volume mixing amount of the steel fibers is 1-2%, and the volume mixing amount of the basalt fibers is 0-1%. The invention greatly improves the resistivity of the ultrahigh-performance fiber reinforced cement-based material while maintaining the good mechanical property of the ultrahigh-performance fiber reinforced cement-based material, and reduces the risk of electrochemical corrosion of the ultrahigh-performance fiber reinforced cement-based material in a complex environment.
Description
Technical Field
The invention relates to the field of building materials, in particular to a high-resistivity ultrahigh-performance fiber reinforced cement-based material and a preparation method thereof.
Background
The ultra-high performance fiber reinforced cement-based material (UHPFRC) is a cement-based material with excellent mechanical property and durability, and is applied to the aspects of building special structures, bridges and the like at present. The excellent mechanical property of the ultra-high performance fiber reinforced cement-based material can not only effectively reduce the volume and the dead weight of the structure, but also meet the requirements of some special structures. For achieving good mechanical properties, a fiber reinforcement mode is generally used in design, because the fiber is mixed to limit the crack propagation when the concrete is damaged, partial load is shared after the matrix is cracked, and the reinforcement effect depends on the strength of the combination between the fiber and the matrix. Among the fibers of different materials used in the preparation of UHPRFC, the most common fiber is copper-plated short steel fiber, which is tightly combined with the matrix and has the best reinforcing effect. However, in some special environments, especially marine environments with high ionic concentrations, the applicability of ultra-high performance fiber-reinforced cement-based materials is unknown.
Disclosure of Invention
The invention provides a fiber reinforced cement-based material and a preparation method thereof for solving the problems. Compared with the traditional fiber reinforced concrete, the fiber reinforced cement-based material has higher resistivity, and reduces the risk of electrochemical corrosion of the concrete in a complex environment.
In order to solve the technical problems, the technical scheme of the invention is as follows:
a fiber reinforced cement-based material, which comprises the following components in percentage by weight: 30-32% of cement, 10-13% of fly ash, 10-16% of coarse sand, 25-33% of fine sand, 4-6% of silica fume, 8-9% of water and 1-1.5% of a water reducing agent, wherein the sum of the components is 100%; the fiber reinforced cement-based material also comprises steel fibers and basalt fibers, wherein the volume mixing amount of the steel fibers is 1-2%, and the volume mixing amount of the basalt fibers is 0-1%.
In the scheme, the diameter of the steel fiber is 0.05-0.2mm, and the length of the steel fiber is 5-20 mm.
In the scheme, the diameter of the basalt fiber is 5-50 μm, and the length of the basalt fiber is 5-15 mm.
In the above scheme, the volume ratio of the steel fibers to the basalt fibers is 1: 1.
in the scheme, the sand is screened commercially available river sand, the particle size of coarse sand is 0.6-1.25mm, and the particle size of fine sand is 0-0.6 mm.
In the scheme, the cement is Portland 52.5 cement.
In the scheme, the fly ash is first-grade fly ash.
In the scheme, the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent, and the solid content is 20%.
The preparation method of the fiber reinforced cement-based material comprises the steps of weighing raw materials according to the mass ratio, mixing and stirring cement, fly ash and silica fume for 30-60 s; then pouring coarse sand and fine sand into the mixed powder, and stirring for 30-60 s; mixing the water reducing agent and 80% of water, pouring the mixture into the material, stirring for 10-20s, adding the rest water, and stirring until the powder is formed into slurry; then stirring according to a standard mortar stirring program; finally, slowly and uniformly pouring the steel fibers, then pouring the basalt fibers, slowly stirring to uniformly mix the fibers and the slurry, and pouring the mixture into a mold for molding.
The principle of the invention is as follows: the non-conductive basalt fiber is adopted to partially replace the steel fiber, so that the volume fraction of the steel fiber is reduced, and the content of the conductive component is reduced; through the technical process of orderly feeding and alternating speed and speed, the two fibers are fully dispersed, and part of basalt fibers invade between adjacent steel fibers to block the direct contact of the steel fibers, so that the possibility of forming a continuous conductive network by the steel fibers is reduced. The intrinsic mechanism of the above two aspects is the basic principle for preparing high resistivity UHPRFC.
The way to realize this principle is: the mass proportion of the raw materials is designed according to the particle composition, so that the powder is densely stacked, and meanwhile, the micropores are filled with high-activity fine powder (silica fume) and the hydration is accelerated to obtain good matrix performance. In the stirring process, the stirring time is longer than that of the conventional cement-based material, so that the water reducer can fully play a role; the slow addition of the fibers can avoid the nonuniform product caused by the fiber agglomeration; the slow-speed stirring is adopted in the processes of adding the fibers and subsequent stirring, so that the problem that the steel fibers are bent by a stirring rotor in the process of rapid stirring to generate agglomeration of the conductive fibers, and the mechanical property of the ultra-high-performance fiber reinforced concrete is reduced and the resistivity is reduced due to excessive winding of the fibers is solved. The basalt fiber is adopted to partially replace the steel fiber, so that the volume content of the steel fiber is reduced while the good reinforcing effect of the steel fiber is exerted, the mutual contact of the steel fiber is reduced, the volume resistivity is improved, and the risk of electrochemical corrosion of the steel fiber can be reduced.
The invention has the beneficial effects that: compared with the traditional steel fiber ultrahigh-performance fiber reinforced concrete, the high-resistivity ultrahigh-performance fiber reinforced cement-based material has higher resistivity, and reduces the risk of electrochemical corrosion of the concrete in a complex environment.
Drawings
FIG. 1 shows the compressive strengths of 1d, 7d and 28d of examples of the present invention and comparative examples.
FIG. 2 shows the 28d flexural strength of the inventive examples and comparative examples.
Fig. 3 is an ac impedance spectrum of comparative example 3.
FIG. 4 is an AC impedance spectrum of example 2.
FIG. 5 is an AC impedance spectrum of example 1.
Detailed Description
The resistivity improving effect is mainly carried out in an alternating current impedance spectrum testing mode, concrete is not an ohmic element, the volume resistance cannot be calculated simply through R ═ U/I, the testing method can separate the resistance and the capacitance effect of a sample, and the error of electrode contact is reduced. The mechanical properties of the invention are illustrated by the compressive strength and flexural strength tests.
The invention provides a fiber reinforced cement-based material, which comprises the following components in percentage by weight: 30-32% of cement, 10-13% of fly ash, 10-16% of coarse sand, 25-33% of fine sand, 4-6% of silica fume, 8-9% of water and 1-1.5% of a water reducing agent, wherein the sum of the components is 100%; the fiber reinforced cement-based material also comprises steel fibers and basalt fibers, wherein the volume mixing amount of the steel fibers is 1-2%, and the volume mixing amount of the basalt fibers is 0-1%.
The diameter of the steel fiber is 0.05-0.2mm, and the length is 5-20 mm. The basalt fiber has a diameter of 5-50 μm and a length of 5-15 mm. The volume ratio of the steel fibers to the basalt fibers is 1-3:1-3, preferably 1: 1.
the sand is commercial river sand screened, the particle size of coarse sand is 0.6-1.25mm, and the particle size of fine sand is 0-0.6 mm. The cement is Portland 52.5 cement. The fly ash is first-grade fly ash. The water reducing agent is a polycarboxylic acid high-efficiency water reducing agent, and the solid content is 20%.
The embodiment also provides a preparation method of the fiber reinforced cement-based material, which comprises the steps of weighing raw materials according to the mass ratio, mixing and stirring cement, fly ash and silica fume for 30-60 s; then pouring coarse sand and fine sand into the mixed powder, and stirring for 30-60 s; mixing the water reducing agent and 80% of water, pouring the mixture into the material, stirring for 10-20s, adding the rest water, and stirring until the powder is formed into slurry; then stirring according to a standard mortar stirring program; finally, slowly and uniformly pouring the steel fibers, then pouring the basalt fibers, slowly stirring to uniformly mix the fibers and the slurry, and pouring the mixture into a mold for molding.
Several specific examples are described below.
Example 1
The raw material formulation of this example is shown in table 1. In this example, the volume ratio of steel fibers SF and pure basalt fibers BF was 3: 1. The volume mixing amount of the steel fiber SF is 1.5 percent, and the volume mixing amount of the basalt fiber is 0.5 percent. Wherein the density of the steel is 7.8g/cm3And density of basalt 2.7g/cm3The mass of the fibres per cubic metre in each blend can be calculated, i.e. the mass of steel fibres and pure basalt fibres given in table 1.
Example 2
The raw material formulation of this example is shown in table 1. In this example, the volume ratio of the steel fiber SF and the pure basalt fiber BF was 1: 1. The volume mixing amount of the steel fiber SF is 1 percent, and the volume mixing amount of the pure basalt fiber is 1 percent.
Example 3
The raw material formulation of this example is shown in table 1. In this example, the volume ratio of the steel fiber SF to the pure basalt fiber BF was 1: 3. The volume mixing amount of the steel fiber SF is 0.5 percent, and the volume mixing amount of the pure basalt fiber is 1.5 percent.
Comparative examples 1 to 4
The raw material formulations of comparative examples 1 to 4 are shown in table 1, and the comparison is made with no fiber, only steel fiber and only basalt fiber, respectively.
TABLE 1 units (Kg/m)3)
According to the mixture ratio of the components shown in the table 1, the ultrahigh-performance fiber reinforced cement-based material is prepared according to the process flow detailed in the invention content, a triple die of 40mm multiplied by 160mm is used for forming, and the product is cured for 28d according to GB/T17671-1999. And adhering electrode plates on two sides of the test block by using graphite conductive adhesive, performing an alternating current impedance spectrum test by using an electrochemical workstation by using a two-electrode method, setting the scanning frequency to be 1Mhz-1hz, drawing an experimental result into a Nyquist diagram, fitting and analyzing the resistivity change of the sample by using software, and testing the flexural strength and the compressive strength by using a mechanical testing machine.
The test result proves that the material of the invention has stable mechanical property. Compared with pure steel fiber ultrahigh-performance fiber reinforced cement-based materials, the high-resistance UHPRFC prepared by the invention has higher resistivity under the condition of meeting the mechanical property.
From fig. 1 and 2, it can be seen that in terms of mechanical properties: compared with comparative example 1 and comparative example 4, the strength advantage of each example is obvious, which shows that maintaining a certain amount of steel fiber is not replaceable in maintaining the mechanical property; compared with the comparative examples 2 and 3, the mechanical properties of the examples 1 and 2 are close to the difference between the two comparative examples, and it can be shown that the mechanical properties are slightly influenced by the fluctuation of the raw materials, when the equal-volume part of the basalt fiber is used for replacing the steel fiber, the loss of the mechanical properties is small, the loss at 1d is about 10 percent, and the loss of the properties at 28d is reduced to about 5 percent; example 3 compared to examples 1 and 2, the 28d compressive strength decreased by about 10MPa, the flexural strength decreased by about 7MPa, and the magnitude was slightly greater.
As can be seen from fig. 3, 4 and 5, the left high-frequency region spectral line is oblate, the right low-frequency region is ray-shaped, which is a quasi-Randles case, the curve is processed according to the Randles curve, software is used to fit the circuit according to the standard Randles curve, and the capacitance (C) in the circuit is replaced by a constant phase angle element (Q), from the circuit data of the software fitting, the Rct of the comparative example 3 is 19.0K Ω, and the Rct of the example 1 and the example 2 is 30.4K Ω and 41.4K Ω, which can be seen in that the resistivity of the example 2 is increased by 117% compared with the comparative example 3 and by 36% compared with the example 2.
The performance of the two aspects is combined, so that the high-resistance ultrahigh-performance fiber reinforced cement-based material can be verified to maintain good mechanical property, effectively improve resistivity and reduce the risk of electrochemical corrosion. While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (8)
1. The preparation method of the fiber reinforced cement-based material is characterized in that the fiber reinforced cement-based material comprises the following components in percentage by weight: 30-32% of cement, 10-13% of fly ash, 10-16% of coarse sand, 25-33% of fine sand, 4-6% of silica fume, 8-9% of water and 1-1.5% of a water reducing agent, wherein the sum of the components is 100%; the fiber reinforced cement-based material also comprises steel fibers and basalt fibers, the volume mixing amount of the steel fibers is 1-2%, the volume mixing amount of the basalt fibers is 0.5-1%, the raw materials are weighed according to the mass ratio, and the cement, the fly ash and the silica fume are mixed and stirred for 30-60 s; then pouring coarse sand and fine sand into the mixed powder, and stirring for 30-60 s; mixing the water reducing agent and 80% of water, pouring the mixture into the material, stirring for 10-20s, adding the rest water, and stirring until the powder is formed into slurry; then stirring according to a standard mortar stirring program; finally, slowly and uniformly pouring the steel fibers, then pouring the basalt fibers, slowly stirring to uniformly mix the fibers and the slurry, and pouring the mixture into a mold for molding.
2. A method of producing fibre reinforced cementitious based material as claimed in claim 1 wherein the steel fibres have a diameter of 0.05 to 0.2mm and a length of 5 to 20 mm.
3. A method of producing a fibre reinforced cement based material according to claim 1, wherein the basalt fibres have a diameter of 5-50 μm and a length of 5-15 mm.
4. The method of making a fiber cement-based material according to claim 1, wherein the volume ratio of steel fibers to basalt fibers is 1: 1.
5. a method of producing a fibre reinforced cement based material according to claim 1, wherein the sand is screened commercial river sand having a grit size of 0.6 to 1.25mm coarse sand and 0 to 0.6mm fine sand.
6. A method of producing fibre reinforced cementitious material as claimed in claim 1 wherein the cement is Portland 52.5 cement.
7. The method of making a fiber cement-based material according to claim 1, wherein the fly ash is a first grade fly ash.
8. The method of preparing a fiber cement-based material according to claim 1, wherein the water reducing agent is a polycarboxylic acid high efficiency water reducing agent having a solid content of 20%.
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| CN110281393A (en) * | 2019-07-08 | 2019-09-27 | 黄贺明 | A kind of ultra-high performance concrete frequency conversion type stirring technique |
| CN112851270A (en) * | 2021-03-24 | 2021-05-28 | 中铁二院重庆勘察设计研究院有限责任公司 | Steel fiber and basalt fiber double-doped colorful ultra-high performance concrete and preparation method thereof |
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| JPS6442345A (en) * | 1987-08-05 | 1989-02-14 | Taisei Corp | Slurry for producing fiber reinforced cement mortar or concrete and its production |
| CN102079647A (en) * | 2010-11-30 | 2011-06-01 | 南京理工大学 | Basalt fiber reinforced cement matrix composite and preparation method thereof |
| KR20120077431A (en) * | 2010-12-30 | 2012-07-10 | 코오롱글로벌 주식회사 | A fiber reinforced concrete for floor slab |
| CN103508713A (en) * | 2013-09-03 | 2014-01-15 | 北京交通大学 | Basalt fiber-reinforced active powder concrete and preparation method thereof |
| KR20160144058A (en) * | 2015-06-08 | 2016-12-16 | 한국건설기술연구원 | Ultra-high performance concrete for mixing micro basalt fiber and macro steel fiber, and manufacturing method for the same |
| CN107010896A (en) * | 2017-04-20 | 2017-08-04 | 福州大学 | A kind of regeneration concrete for filling be chopped basalt fibre and regenerated coarse aggregate |
-
2018
- 2018-05-23 CN CN201810500926.5A patent/CN108658536B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6442345A (en) * | 1987-08-05 | 1989-02-14 | Taisei Corp | Slurry for producing fiber reinforced cement mortar or concrete and its production |
| CN102079647A (en) * | 2010-11-30 | 2011-06-01 | 南京理工大学 | Basalt fiber reinforced cement matrix composite and preparation method thereof |
| KR20120077431A (en) * | 2010-12-30 | 2012-07-10 | 코오롱글로벌 주식회사 | A fiber reinforced concrete for floor slab |
| CN103508713A (en) * | 2013-09-03 | 2014-01-15 | 北京交通大学 | Basalt fiber-reinforced active powder concrete and preparation method thereof |
| KR20160144058A (en) * | 2015-06-08 | 2016-12-16 | 한국건설기술연구원 | Ultra-high performance concrete for mixing micro basalt fiber and macro steel fiber, and manufacturing method for the same |
| CN107010896A (en) * | 2017-04-20 | 2017-08-04 | 福州大学 | A kind of regeneration concrete for filling be chopped basalt fibre and regenerated coarse aggregate |
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