CN103274653B - High-flexibility and low-shrinkage fiber reinforced cement-based composite material - Google Patents
High-flexibility and low-shrinkage fiber reinforced cement-based composite material Download PDFInfo
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- CN103274653B CN103274653B CN201310169093.6A CN201310169093A CN103274653B CN 103274653 B CN103274653 B CN 103274653B CN 201310169093 A CN201310169093 A CN 201310169093A CN 103274653 B CN103274653 B CN 103274653B
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Abstract
The invention belongs to the technical field of building materials, and in particular relates to a high-flexibility and low-shrinkage fiber reinforced cement-based composite material. The composite material is prepared by mixing cement, coal ash, silicon powder, gypsum, an expanding agent, a water reducing agent, a shrinkage reducing agent, a defoaming agent, a thickening agent, fine sand, fibers and water, wherein the total mass percentage of the cement, the coal ash, the silicon powder, the gypsum, the expanding agent, the water reducing agent, the shrinkage reducing agent, the defoaming agent, the thickening agent, the fine sand and the fibers is 77-85 percent, and the mass percentage of the water is 15-23 percent. The fiber reinforced cement-based composite material has the performance characteristics of low shrinkage, high flexibility, small crack width, quickness in condensation and early strength and is high in compressive strength and good in synergism with other materials.
Description
Technical field
The invention belongs to building material technical field, particularly the low drying shrinkage fiber reinforced cement-based composite material of a kind of high tenacity.
Background technology
Concrete is a kind of typical hard brittle material, and its bearing capacity after load-bearing reaches peak load sharply declines, and distortion is concentrated and occurred in incipient crack cracks.Therefore namely there is crackle in normal concrete works after stress exceedes concrete tensile strength.For the distortion needed for balancing machine, environmental load, crack width will extend to macroscopical visible horizon.Cracking not only reduces the bearing capacity of works, and makes moisture directly contact reinforcing bar with harmful chemical pierce through the protection layer, finally causes the reduction of works weather resistance.
Solve concrete long-term durable problem, while improving the anti-permeability performance under the non-cracking state of concrete material, the fracture width after also wanting control texture to ftracture under complex environment.Disclose the academic paper of " the From micromechanics to structural engineering-the design of cementitious composites for civil engineering application " by name that a section is delivered by Victor C.Li in the Journal of JSCE of the 10th volume the 2nd phase in 1993, which illustrate a kind of high-tenacity fiber refinforced cement based composites through Micromechanical Design.This material macroscopic view Ultimate Tensile strain can reach 3% ~ 5%, and its mechanism for form many tiny cracks (single crack width is about 80 μm, crack spacing about 10mm) in material tension process.The feature of macroscopic view tensile stress-strain stress relation is do not reduce with the increase tensile stress of stretching strain, the strain hardening phenomenon namely usually said.In drawing process, the formation of many microcracks makes macroscopical stretching strain of material increase over one hundred times.Due to the bridge joint effect of fiber between crackle, the transmission force property of material monolithic is not weakened because of the formation of hair line.Due to excellent stress-strain property and control of crack width function, the following application in civil engineering work of this material has caused the extensive concern of Chinese scholars.
There is larger defect, i.e. its base material dry shrinkage excessive (drying shrinkage reached 1500 ~ 2000 microstrains in 28 days) in high ductility fiber reinforced cement-based composite material.Although crack width is under control after cracking, because material drying shrinkage is excessive, its cracking risk increases, and be obviously deteriorated with the collaborative work of other material (normal concrete 28 the Heavenly Stems shrinkage strain is usually in 400 ~ 800 microstrains).
Summary of the invention
Not enough for prior art, the invention provides the low drying shrinkage fiber reinforced cement-based composite material of a kind of high tenacity.
The low drying shrinkage fiber reinforced cement-based composite material of a kind of high tenacity, this matrix material is mixed by cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand, fiber and water, total mass per-cent wherein shared by cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand and fiber is 77% ~ 85%, and it is 15% ~ 23% that water accounts for mass percent.
The concrete mass percent of described cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand and fiber is as follows:
Cement 20% ~ 26%;
Flyash 6.6% ~ 8.7%;
Silica flour 1.7% ~ 2.2%;
Gypsum 1.7% ~ 2.2%;
Swelling agent 3.3% ~ 4.3%;
Water reducer 0.3% ~ 0.7%;
Economization agent 0.7% ~ 0.9%;
Defoamer 0.06% ~ 0.08%;
Thickening material 0.010% ~ 0.014%;
Fine sand 33% ~ 48%;
Fiber 0.8% ~ 1.0%.
Described cement to be strength grade the be aluminosulfate cement of 42.5 grades.
Described flyash is one-level Class F fly ash.
The unformed SiO of described silica flour
2content is greater than 90%.
Described gypsum is high-strength building gypsum plaster.
Described swelling agent is commercially available sulplo-aluminate class cement expansive material; Described economization agent is commercially available economization agent for concrete; Described defoamer is commercially available concrete defoamer; Described thickening material is commercially available concrete water-retaining admixture.
Described thickening material is methyl cellulose ether or hydroxypropyl methyl cellulose ether.
Described water reducer is polycarboxylic acids dehydragent or naphthalene system-sulfamate composite water-reducing agent.
Described fine sand is 100 ~ 200 order quartz sands.
Described fiber is polyvinyl alcohol fiber, and described staple length is 12mm, and Fibre diameter is 39 μm.
Beneficial effect of the present invention is:
Fiber reinforced cement-based composite material of the present invention has that drying shrinkage is low, toughness is high, crack width is little, the performance characteristics of quick setting early strength, also has higher ultimate compression strength, good collaborative work with other materials simultaneously, is specially:
1. low drying shrinkage
For reaching the low drying shrinkage of high-tenacity fiber refinforced cement sill, add swelling agent in the feed.Its mechanism is: when the premature cure process of cement, the swelling agent added and the hydrated product of cement react the ettringite generating and have microdilatancy usefulness, base material (mortar) appropriateness of high-toughness material is expanded, compensates all kinds of shrinkage strain.
Test shows, the cement-base composite material after material compensation process is compared with traditional high-tenacity fiber refinforced cement based composites, and the shrinkage value of 28d is reduced to 200 microstrains by 1500 microstrains, reduces 87%.And shrinkage value is lower than normal concrete, mean that the low drying shrinkage fiber reinforced cement-based composite material of high tenacity also can not ftracture in the indehiscent structure of normal concrete, greatly reduces the cracking risk of traditional high-tenacity fiber refinforced cement sill.
2. high tenacity
For realizing the high tenacity of material, fiber, base material (mortar) and fiber-substrate interface characteristic must via rational Micromechanical Designs.The Young's modulus of the polyvinyl alcohol fiber that the present invention selects and base material are quite, intensity is higher, good with the adhesive property of base material.The matched well of substrate performance (intensity, fracture toughness property etc.) and this kind of fiber is realized by adjustment water-cement ratio.The cement-based material designed so also can realize high tenacity, microcrack width except having low drying shrinkage.
This material macroscopic view Ultimate Tensile strain can reach 3%-5%, and its mechanism for form many tiny cracks (single crack width is about 80 μm, crack spacing about 10mm) in material tension process.The feature of macroscopic view tensile stress-strain stress relation is do not reduce with the increase tensile stress of stretching strain, the strain hardening phenomenon namely usually said.In drawing process, the formation of many microcracks makes macroscopical stretching strain of material increase over one hundred times.Due to the bridge joint effect of fiber between crackle, the transmission force property of material monolithic is not weakened because of the formation of hair line.
3. good compressive property
As a kind of Structural Engineering material, the high tenacity that the present invention relates to low drying shrinkage fiber reinforced cement-based composite material, except having the characteristic of high tenacity, low drying shrinkage, also should have good compressive property.Owing to selecting sand-cement slurry as the base material of material, fiber is to the bridge joint effect of Original Cracks, running crack in addition, and this material can obtain good compressive property.By adjustment water-cement ratio, the 28d ultimate compression strength of material can reach 20 ~ 30MPa, and corresponding ultimate compressive strain can reach more than 0.3%.
Embodiment
The invention provides the low drying shrinkage fiber reinforced cement-based composite material of a kind of high tenacity, below in conjunction with embodiment, the present invention will be further described.
Embodiment 1
The low drying shrinkage fiber reinforced cement-based composite material of a kind of high tenacity, it is mixed by cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand, fiber and water, wherein total mass per-cent shared by cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand and fiber is 80.5%, and it is 19.5% that water accounts for mass percent.
Cement is the quick hardening sulphoaluminate cement of strength grade 42.5 grades; Flyash is one-level Class F fly ash; The SILICA FUME of the Gansu three silicon materials company limited far away production of silica flour; Gypsum is high-strength building gypsum plaster; Swelling agent is commercially available ZY expansion agent for composite type concrete; Water reducer is high-efficiency water-reducing agent of poly-carboxylic acid; Economization agent is commercially available economization agent for concrete; Defoamer is the Lumiten EL type defoamer that Shanghai BASF Auxiliary Chemicals Co., Ltd. produces; Thickening material is commercially available concrete water-retaining admixture, and its component is hydroxypropyl methyl cellulose ether; Fine sand is 100 ~ 200 order quartz sands; Fiber is the polyvinyl alcohol fiber that Japanese Kuraray company produces.The mass percent of above-mentioned each component is as follows:
Quick hardening sulphoaluminate cement 26%; Flyash 8.7%; Silica flour 2.2%; Terra alba 2.2%; Swelling agent 4.3%; High-efficiency water-reducing agent of poly-carboxylic acid 0.4%; Economization agent 0.87%; Defoamer 0.08%; Water-retaining admixture 0.01%; 100 ~ 200 order quartz sands 35%; Polyvinyl alcohol fiber 1%.
The preparation of the low drying shrinkage fiber reinforced cement-based composite material of above-mentioned a kind of high tenacity: by cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand, fiber and water mix and blend, obtain product.
The test-results that the present embodiment obtains the properties of product lists in table 1.Wherein, mechanical test test block used, after the demoulding in 24 hours, is put into standard curing room and is carried out water curing (temperature is 20 ± 2 DEG C), carry out tension, compression tests after 28 days on mechanics machine; Dry shrinkage testing adopts cement mortar expansion gauge to carry out, and test block places form removal after 24 hours under standard test condition, then measures its shrinkage value under each length of time.
Table 1 embodiment 1 high tenacity low drying shrinkage fiber reinforced cement-based composite material table with test results (28 days)
| Tensile strength/MPa | 4.84 |
| Ultimate tensile strength/% | 1.49 |
| Ultimate compression strength/MPa | 27.54 |
| Compressive ultimate strain/% | 0.55 |
| Shrinkage value/μ ε | 109 |
Embodiment 2
The low drying shrinkage fiber reinforced cement-based composite material of a kind of high tenacity, it is mixed by cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand, fiber and water, wherein mass percent shared by cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand and fiber is 79%, and it is 21% that water accounts for mass percent.
Cement is the quick hardening sulphoaluminate cement of strength grade 42.5 grades; Flyash is one-level Class F fly ash; The SILICA FUME of the Gansu three silicon materials company limited far away production of silica flour; Gypsum is high-strength building gypsum plaster; Swelling agent is commercially available ZY expansion agent for composite type concrete; Water reducer is naphthalene system-sulfamate composite superplasticizer; Economization agent is commercially available economization agent for concrete; Defoamer is the Lumiten EL type defoamer that Shanghai BASF Auxiliary Chemicals Co., Ltd. produces; Thickening material is commercially available concrete water-retaining admixture, and its component is hydroxypropyl methyl cellulose ether; Fine sand is 100 ~ 200 order quartz sands; Fiber is the polyvinyl alcohol fiber that Japanese Kuraray company produces.The mass percent of above-mentioned each component is as follows:
Quick hardening sulphoaluminate cement 25.5%; Flyash 8.55%; Silica flour 2.2%; Terra alba 2.2%; Swelling agent 4.2%; High-efficiency water-reducing agent of poly-carboxylic acid 0.4%; Economization agent 0.85%; Defoamer 0.08%; Water-retaining admixture 0.02%; 100 ~ 200 order quartz sands 34%; Polyvinyl alcohol fiber 1%.
The preparation of the low drying shrinkage fiber reinforced cement-based composite material of above-mentioned a kind of high tenacity: by cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand, fiber and water mix and blend, obtain product.
The test-results that the present embodiment obtains the properties of product lists in table 2.Wherein, mechanical test test block used, after the demoulding in 24 hours, is put into standard curing room and is carried out water curing (temperature is 20 ± 2 DEG C), carry out tension, compression tests after 28 days on mechanics machine; Dry shrinkage testing adopts cement mortar expansion gauge to carry out, and test block places form removal after 24 hours under standard test condition, then measures its shrinkage value under each length of time.
Table 2 embodiment 2 high tenacity low drying shrinkage fiber reinforced cement-based composite material test result (28 days)
| Tensile strength/MPa | 4.03 |
| Ultimate tensile strength/% | 1.24 |
| Ultimate compression strength/MPa | 20.94 |
| Compressive ultimate strain/% | 0.45 |
| Shrinkage value/μ ε | 202 |
Claims (7)
1. the low drying shrinkage fiber reinforced cement-based composite material of high tenacity, it is characterized in that: this matrix material is mixed by cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand, fiber and water, total mass per-cent wherein shared by cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand and fiber is 77% ~ 85%, and it is 15% ~ 23% that water accounts for mass percent;
The concrete mass percent of described cement, flyash, silica flour, gypsum, swelling agent, water reducer, economization agent, defoamer, thickening material, fine sand and fiber is as follows:
Described cement to be strength grade the be aluminosulfate cement of 42.5 grades;
Described fine sand is 100 ~ 200 order quartz sands;
Described fiber is polyvinyl alcohol fiber, and described staple length is 12mm, and Fibre diameter is 39 μm.
2. matrix material according to claim 1, is characterized in that: described flyash is one-level Class F fly ash.
3. matrix material according to claim 1, is characterized in that: the unformed SiO2 content of described silica flour is greater than 90%.
4. matrix material according to claim 1, is characterized in that: described gypsum is high-strength building gypsum plaster.
5. matrix material according to claim 1, is characterized in that: described swelling agent is commercially available sulplo-aluminate class cement expansive material; Described economization agent is commercially available economization agent for concrete; Described defoamer is commercially available concrete defoamer; Described thickening material is commercially available concrete water-retaining admixture.
6. matrix material according to claim 5, is characterized in that: described thickening material is methyl cellulose ether or hydroxypropyl methyl cellulose ether.
7. matrix material according to claim 1, is characterized in that: described water reducer is polycarboxylic acids dehydragent or naphthalene system-sulfamate composite water-reducing agent.
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| CN104211358B (en) * | 2014-09-11 | 2016-06-22 | 中国中材国际工程股份有限公司 | A kind of high-early-strength high ductility cement-base composite material and preparation method thereof |
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