CN111217560A - Asbestos-free straw fiber reinforced cement board and preparation method thereof - Google Patents

Asbestos-free straw fiber reinforced cement board and preparation method thereof Download PDF

Info

Publication number
CN111217560A
CN111217560A CN202010107090.XA CN202010107090A CN111217560A CN 111217560 A CN111217560 A CN 111217560A CN 202010107090 A CN202010107090 A CN 202010107090A CN 111217560 A CN111217560 A CN 111217560A
Authority
CN
China
Prior art keywords
water
parts
asbestos
straw fiber
fiber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
CN202010107090.XA
Other languages
Chinese (zh)
Inventor
吕春粉
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zhengzhou Zhitao Information Technology Co ltd
Original Assignee
Zhengzhou Zhitao Information Technology Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Zhengzhou Zhitao Information Technology Co ltd filed Critical Zhengzhou Zhitao Information Technology Co ltd
Priority to CN202010107090.XA priority Critical patent/CN111217560A/en
Publication of CN111217560A publication Critical patent/CN111217560A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B28WORKING CEMENT, CLAY, OR STONE
    • B28BSHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B1/00Producing shaped prefabricated articles from the material
    • B28B1/52Producing shaped prefabricated articles from the material specially adapted for producing articles from mixtures containing fibres, e.g. asbestos cement
    • B28B1/525Producing shaped prefabricated articles from the material specially adapted for producing articles from mixtures containing fibres, e.g. asbestos cement containing organic fibres, e.g. wood fibres
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B28WORKING CEMENT, CLAY, OR STONE
    • B28BSHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B11/00Apparatus or processes for treating or working the shaped or preshaped articles
    • B28B11/24Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
    • B28B11/243Setting, e.g. drying, dehydrating or firing ceramic articles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B28WORKING CEMENT, CLAY, OR STONE
    • B28BSHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B11/00Apparatus or processes for treating or working the shaped or preshaped articles
    • B28B11/24Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
    • B28B11/245Curing concrete articles
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B20/00Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
    • C04B20/02Treatment
    • C04B20/023Chemical treatment
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/20Resistance against chemical, physical or biological attack
    • C04B2111/27Water resistance, e.g. waterproof or water-repellant materials
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/20Resistance against chemical, physical or biological attack
    • C04B2111/28Fire resistance, i.e. materials resistant to accidental fires or high temperatures
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/76Use at unusual temperatures, e.g. sub-zero
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2201/00Mortars, concrete or artificial stone characterised by specific physical values
    • C04B2201/50Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength

Abstract

The invention relates to an asbestos-free straw fiber reinforced cement board and a preparation method thereof, wherein the straw fiber reinforced cement board is mainly prepared from the following raw materials in parts by weight: 6-8 parts of modified wheat straw fiber, 5-6 parts of silica fume, 48-52 parts of cement, 10-12 parts of metakaolin, 20-22 parts of quartz sand and 5-6 parts of fly ash; the preparation method of the modified wheat straw fiber comprises the following steps: 1) cutting dried wheat straws into short materials, and soaking and softening the short materials by using water to obtain a prepared material; 2) performing steam explosion on the prepared material to obtain a blasting material; 3) sequentially carrying out alkaline leaching and water washing on the blasting material to obtain a fiber material; 3) and (3) modifying the fiber material by using gamma-aminopropyltriethoxysilane. The asbestos-free straw fiber reinforced cement board has the advantages of good appearance quality, low water absorption and wet expansion rate, good water and moisture resistance, high mechanical property, good freeze-thaw resistance, hot water and dry-wet cycle performance, stable property, environmental protection and capability of replacing wood pulp fiber reinforced cement boards.

Description

Asbestos-free straw fiber reinforced cement board and preparation method thereof
Technical Field
The invention belongs to the technical field of fiber reinforced cement boards, and particularly relates to an asbestos-free straw fiber reinforced cement board and a preparation method thereof.
Background
The fiber reinforced cement board (also called fiber cement board) is a water-hardening artificial board which is prepared by using hardened cement paste or mortar as a base material and fibers as a reinforcing material through the processes of pulping, forming, maintaining, drying and the like; depending on the type of reinforcing fibers used, they can be classified into chrysotile fiber cement boards reinforced with asbestos fibers and non-asbestos fiber cement boards reinforced with other fibers (without asbestos).
The fiber reinforced cement board has the excellent characteristics of fire prevention, insulation, water prevention, moisture prevention, heat insulation, sound insulation, light weight, high strength, simple and convenient construction, good decorative effect, safety, harmlessness, long service life and the like, has a very wide application range, and can be used as a sound absorption and ceiling material because a thin board (with the thickness of 2.5-3.5mm) can be perforated; the conventional board (thickness 4-12mm) can be used as wall and decorative material, such as indoor partition lining board, composite wall panel, outdoor billboard, industrial electric furnace heat insulation board, electrical and electronic power distribution cabinet, transformer partition board, etc.; the thick plate (thickness 13-30mm) and the super-thick plate (thickness 31-100mm) can be used as steel structure floor plates, pavilion floor plates, external wall heat-insulating plates, external wall cladding plates and the like.
In recent years, in order to avoid the occurrence of asbestos-related diseases such as asbestos lung, lung cancer, mesothelioma, etc., research on fiber-reinforced cement boards at home and abroad has been focused on the development of novel substitute fibers, and asbestos-free fiber-reinforced cement boards have been developed, using fiber materials including pulp fibers, glass fibers, synthetic fibers (such as polypropylene fibers, polyvinyl alcohol fibers, aramid fibers), organic and inorganic composite fibers, etc. At present, the chemically treated softwood wood pulp fibers are used more frequently, for example, the wood pulp fibers prepared from the raw materials of the mountain pine, the slash pine and the like are harmless to the human health compared with chrysotile; compared with glass fiber and synthetic fiber, wood pulp fiber belongs to renewable resources and has wide sources. The coniferous wood pulp mainly made of pine wood has moderate fiber length, has better interfacial adhesion with cement after bleaching, can overcome the problem of dry shrinkage of common cement products, and plays a role in strengthening. In the prior art, hardwood (such as eucalyptus) pulp is also used as a raw material to prepare the fiber reinforced cement board, but the hardwood pulp pulping process needs to be further optimized and improved, fiber damage is reduced, and the softwood pulp can be completely replaced.
However, wood resources in China are relatively deficient and scarce, because the coverage rate of forests is not high, the yield of the woods in China is obviously reduced in order to protect the tree resources in forest zones and maintain good ecological environment, and commercial felling is forbidden gradually, and the competition among downstream industries taking the woods as raw materials is intense, so that fiber cement board manufacturers taking wood pulp fibers as reinforcing materials mainly rely on imported wood pulp, the price and the transportation cost are high, and the industrial development and application of green environment-friendly fiber reinforced cement boards are limited.
Disclosure of Invention
The invention aims to provide a non-asbestos straw fiber reinforced cement board.
The second purpose of the invention is to provide a preparation method of the asbestos-free straw fiber reinforced cement board.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the asbestos-free straw fiber reinforced cement board is mainly prepared from the following raw materials in parts by weight:
6-8 parts of modified wheat straw fiber, 5-6 parts of silica fume, 48-52 parts of cement, 10-12 parts of metakaolin, 20-22 parts of quartz sand and 5-6 parts of fly ash;
wherein the modified wheat straw fiber is prepared by the method comprising the following steps:
1) cutting dried wheat straw into short materials, soaking in water for 12-16h for softening, and taking out to obtain the prepared material;
2) performing steam explosion on the prepared material obtained in the step 1), wherein the steam temperature is 175-180 ℃, the explosion pressure is 2.4-2.8MPa, the pressure maintaining time is 4.0-5.0min, and then discharging the material to obtain a blasting material;
3) soaking the blasting material obtained in the step 2) in a sodium hydroxide solution with the mass concentration of 1.0-2.0% for 2-3h, taking out and washing with water to obtain a fiber material;
4) dissolving gamma-aminopropyltriethoxysilane in an ethanol water solution to prepare a modifier, uniformly mixing the modifier with the fiber material obtained in the step 3), and drying to remove ethanol to obtain the modified wheat straw fiber.
The particle size of the silica fume is 0.05-0.15 μm; the particle size of the metakaolin is 1-3 mu m; the particle size of the quartz sand is 200-300 meshes; the particle size of the fly ash is 300-500 meshes.
The raw materials also comprise 0-2.5 parts of auxiliary agent by weight. The auxiliary agent is any one or combination of a water reducing agent, a release agent, a thickening agent, a waterproof agent and a retarder. The auxiliary agent can be selected according to actual production conditions, and the conventional commercial type in the field can be selected according to requirements.
In the step 1), the length of the short material is 20-40 mm. Soaking in water at room temperature. Taking out and draining until the water drops are not in flow, and then carrying out subsequent steam explosion operation.
In the step 3), the water washing refers to repeatedly rinsing with water until the solution is neutral.
In step 3), the fiber material is sieved before use. Sieving refers to the removal of excessively finely divided fiber powder. Preferably, the fiber material with the fiber length not less than 2mm is obtained by screening and is ready for use.
In the step 4), the dosage of the gamma-aminopropyl triethoxysilane is 1.0-1.2% of the mass of the fiber material.
The preparation method of the asbestos-free straw fiber reinforced cement board comprises the following steps:
a) adding the modified wheat straw fiber with the formula amount into water for pulping and defibering, wherein the pulping degree is 20.0-25.0 DEG SR, and obtaining fiber pulp with the mass concentration of 2.4-2.6%;
b) adding silica fume and metakaolin into the fiber slurry obtained in the step a), continuously shearing and dispersing for 10-15min, then adding a dry material prepared by mixing cement, fly ash and quartz sand and water to prepare a mixed slurry, then preparing a wet blank through a forming process, and then performing pre-curing, autoclaved curing and drying to obtain the fiber slurry.
In the step b), the temperature of the pre-curing is 60-80 ℃, and the time is 3-5 h; the temperature of the steam pressure curing is 175-185 ℃, the pressure is 0.8-1.2MPa, and the time is 6-8 h.
In the step b), the water content of the mixed slurry is controlled to be more than or equal to 90%, the water content of the wet blank is controlled to be less than or equal to 32%, and the water content of the plate blank obtained after autoclaved curing is controlled to be less than or equal to 30%.
In the step b), the drying temperature is 105-110 ℃, and the drying is carried out until the water content of the plate reaches below 7.0%.
The asbestos-free straw fiber reinforced cement board takes modified wheat straw fiber as a reinforcing material, takes silica fume and metakaolin as fillers, takes quartz sand as fine aggregate and takes fly ash as mineral admixture. The modified wheat straw fiber is prepared by cutting dried wheat straws into short materials, soaking the short materials in water for 12-16h to soften the short materials to obtain prepared materials, and the purpose of softening by water soaking is to prevent the wheat straws from being excessively crushed into powder after steam explosion in a dry state.
The invention carries out steam explosion on the prepared material, controls the steam temperature of the steam explosion to be 175-180 ℃, the explosion pressure to be 2.4-2.8MPa, the pressure holding time to be 4.0-5.0min, the wheat straws are quickly heated to the set temperature by high-temperature steam, the steam is diffused and permeated into the fiber cell walls of the wheat straws under high pressure, the cellulose, the hemicellulose and the colloid in the wheat straws are activated to be hydrolyzed under the condition of high temperature and high pressure, the lignin is softened, the polymerization degree of the fiber bundles is reduced, the fibers bound by the colloid are gradually loosened, the lignin bonded with the cellulose is partially peeled off, the pressure is suddenly released during pressure relief, the temperature is quickly reduced, the moistened wheat straws are exploded, the raw material is torn into fine fibers, the cellulose fibers with better strength and toughness after separation and refinement are obtained, and the fibers are prepared by breaking through the wheat straws from inside to outside due to the steam explosion, the fiber has high fibrillation rate, good water retention and adsorption. Through steam explosion treatment, cellulose and hemicellulose in the wheat straw fiber are degraded, carbohydrate and acid substances are increased, macromolecular carbohydrate is decomposed into micromolecular carbohydrate, biomass with certain viscosity is formed with activated lignin, the obtained blasting material is soaked for 2-3 hours by using sodium hydroxide solution with the mass concentration of 1.0-2.0%, so that the viscous substance and the non-fibrous substance are fully dissolved out, and the obtained blasting material is washed and removed to obtain pure fiber material.
The invention dissolves gamma-aminopropyl triethoxy silane in ethanol water solution to prepare modifier, and the modifier and the obtained fiber material are evenly mixed and dried to remove ethanol, thus obtaining the modified wheat straw fiber. The fiber material is modified by gamma-aminopropyltriethoxysilane, the hydrophilicity of the wheat straw fiber is reduced, the water retention property and the dispersibility of the fiber in slurry are improved, and the alkali resistance and the interface bonding force with a cement matrix are enhanced. The ethanol water is adopted as the solvent, which is beneficial to the hydrolysis of the gamma-aminopropyl triethoxysilane and the spreading on the fiber surface, the dosage of the gamma-aminopropyl triethoxysilane is saved, the subsequent process is prevented from being influenced, and the used ethanol can be recycled.
When the non-asbestos straw fiber reinforced cement board is prepared, the obtained modified wheat straw fibers are added into water for pulping and defibering, the pulping degree and the fiber pulp concentration are controlled, the fibers in the obtained fiber pulp are uniformly dispersed and have good brooming degree, the subsequent adsorption of cement particles and hydration products thereof is facilitated, the binding force between material layers is improved, and the layering phenomenon is inhibited.
According to the invention, the silica fume and the metakaolin are added into the obtained fiber slurry, and the shearing and the dispersion are continued for 10-15min, so that a part of superfine powder materials of the silica fume and the metakaolin are firstly adsorbed on the surface of the reinforced fiber, the adsorption effect of the reinforced fiber on cement particles is enhanced, and then the dry material prepared by mixing the cement, the fly ash and the quartz sand and water are added to prepare the mixed slurry. Metakaolin can also rapidly react with calcium hydroxide generated by cement hydration to generate viscous mixtures such as ettringite, calcium silicate gel and the like, so that the interface bonding strength of the fiber and the base material is improved; meanwhile, the alkalinity of the cement base material can be reduced, the damage effect on the self structure of the wheat straw fiber is reduced, and the reinforcing effect of the fiber is improved. The quartz sand is used as the fine aggregate of the cement base material, and the fly ash is used as the mineral admixture for improving the strength and the mechanical property of the plate. The mixed slurry is made into a wet blank through a forming process, and then the wet blank is subjected to pre-curing, autoclaved curing and drying to obtain the plate, wherein the pre-curing and autoclaved curing parameters are scientifically and reasonably designed, and the obtained plate has stable properties and high quality.
The asbestos-free product of the inventionThe surface of the finished product of the straw fiber reinforced cement board (original board) has no phenomena of crack, delamination, peeling and bubbling, and has no obvious corner drop and edge drop, thereby meeting the requirement of appearance quality. The detection shows that the water absorption rate of the obtained board is below 16.23 percent, the hygroexpansion rate is below 0.13 percent, which indicates that the combination between the wheat straw fiber reinforced material and the matrix in the board is tighter, the porosity is small, the board is not easy to absorb water, and the board has better water resistance and moisture resistance; the incombustibility of the obtained plate meets the requirement of GB8624 incombustibility A, and after the water impermeability test lasts for 24 hours, no water drops appear on the bottom surface of the plate, so that the water impermeability requirement is met. In a mechanical property detection test, the water saturation breaking strength of the obtained plate is not lower than 13MPa, and the R3-level strength requirements of A-type and B-type plates are met; the impact strength is not lower than 1.8kJ/m3Meets the C3-grade strength requirement of the plate with the thickness e less than or equal to 14 mm. In an anti-freezing test, after 100 times of freeze-thaw cycles, the water-saturated breaking strength of the obtained plate is still more than 10.71MPa, the breaking strength ratio is more than 80.77%, the strength loss is small, and the plate has good anti-freezing performance; in a hot water test, the water saturation breaking strength of the obtained plate is still more than 9.89MPa, the breaking strength ratio is more than 74.26%, the strength loss is small, and the plate has good damp-heat resistance stability; in a soaking-drying test, the obtained board has the water saturation breaking strength of more than 11.38MPa, the breaking strength ratio of more than 84.67 percent, small strength loss and good dry and wet resistance stability. The obtained asbestos-free straw fiber reinforced cement board has excellent comprehensive performance and can replace the application of the existing wood pulp fiber reinforced cement board.
Detailed Description
The present invention will be further described with reference to the following embodiments.
In a specific embodiment, the used dry wheat straws are purchased from local farmers, have the water content of 15-20 percent and are cleaned of impurities such as soil, dust, weeds and the like before use.
In a specific embodiment, the cement is commercially available ordinary portland cement with a strength grade of 42.5 #. The used silica fume is a commercial product, and the particle size is 0.05-0.15 μm. The metakaolin is a commercial product and is prepared by calcining metakaolin at 800 deg.C for 4 hr, and has average particle diameter of not more than 1.0 μm and specific gravity of 2.58g/cm3The activity is 35-40%. The quartz sand is commercially available product with particle size of 200-300 meshes and SiO2The content is more than 99.6 percent. The fly ash is a commercial product, the particle size is 300-500 meshes, and the density is 2.29g/cm3
In the specific embodiment, the forming process comprises a sheet-making method, extrusion dehydration and compression forming.
Example 1
The asbestos-free straw fiber reinforced cement board is mainly prepared from the following raw materials in parts by weight:
6.5 parts of modified wheat straw fiber, 5.5 parts of silica fume, 52 parts of cement, 10 parts of metakaolin, 21 parts of quartz sand and 5 parts of fly ash.
The preparation method of the asbestos-free straw fiber reinforced cement board comprises the following steps:
1) cutting dried wheat straws into short materials with the length of 20-40mm, soaking the short materials in clear water for 12 hours at room temperature to soften the short materials, taking out the short materials, draining the short materials until water drops do not flow down in strands any more, and obtaining a prepared material;
2) placing the prepared material obtained in the step 1) in a steam explosion device for steam explosion, wherein the steam temperature is 175 ℃, the explosion pressure is 2.8MPa, the pressure maintaining time is 4.5min, and then discharging the material to obtain the explosive material;
3) soaking the blasting material obtained in the step 2) for 3 hours by using a sodium hydroxide solution with the mass concentration of 1.5%, repeatedly rinsing the blasting material by using water until the blasting material is neutral and fibers are not adhered, and screening the blasting material to obtain a fiber material with the length of 2-5 mm;
4) dissolving gamma-aminopropyltriethoxysilane in an ethanol water solution (the mass ratio of ethanol to water is 82:8) to prepare a modifier with the mass concentration of 10%, uniformly mixing the obtained modifier with the fiber material obtained in the step 3), and drying to remove ethanol (ethanol is recycled and reused) to obtain modified wheat straw fibers; wherein the dosage of the gamma-aminopropyl triethoxysilane is 1.1 percent of the mass of the fiber material;
5) adding the modified fiber material obtained in the step 4) into water for pulping and defibering, wherein the pulping degree is 21.0 DEG SR, and obtaining fiber pulp with the mass concentration of 2.5%;
6) adding silica fume and metakaolin into the fiber slurry obtained in the step 5), continuously shearing and dispersing for 10min, then adding dry materials prepared by mixing cement, fly ash and quartz sand and water to prepare mixed slurry, and controlling the water content of the mixed slurry to be more than or equal to 90%; then a wet blank is prepared by a forming process (a copying method), and the water content of the wet blank is controlled to be less than or equal to 32 percent; pre-curing for 5h at the temperature of 60 ℃, then performing autoclaved curing for 8h at the temperature of 185 ℃ and the pressure of 0.8MPa (controlling the water content of the plate blank obtained after the autoclaved curing to be less than or equal to 30%), and drying at the temperature of 105 ℃ until the water content of the plate reaches less than 7.0%, thus obtaining the asbestos-free straw fiber reinforced cement plate.
Example 2
The asbestos-free straw fiber reinforced cement board is mainly prepared from the following raw materials in parts by weight:
7 parts of modified wheat straw fiber, 6 parts of silica fume, 50 parts of cement, 11 parts of metakaolin, 20 parts of quartz sand and 6 parts of fly ash.
The preparation method of the asbestos-free straw fiber reinforced cement board comprises the following steps:
1) cutting dried wheat straws into short materials with the length of 20-40mm, soaking the short materials for 14h at room temperature for softening, taking out the short materials, draining the short materials until water drops are not formed and flow down in strands, and obtaining a prepared material;
2) placing the prepared material obtained in the step 1) in a steam explosion device for steam explosion, wherein the steam temperature is 180 ℃, the explosion pressure is 2.4MPa, the pressure maintaining time is 5.0min, and then discharging the material to obtain the explosive material;
3) soaking the blasting material obtained in the step 2) in a sodium hydroxide solution with the mass concentration of 1.8% for 2.5h, repeatedly rinsing with water until the blasting material is neutral and fibers are not adhered, and screening to obtain a fiber material with the length of 2-5 mm;
4) dissolving gamma-aminopropyltriethoxysilane in an ethanol water solution (the mass ratio of ethanol to water is 82:8) to prepare a modifier with the mass concentration of 10%, uniformly mixing the obtained modifier with the fiber material obtained in the step 3), and drying to remove ethanol (ethanol is recycled and reused) to obtain modified wheat straw fibers; wherein the dosage of the gamma-aminopropyl triethoxysilane is 1.0 percent of the mass of the fiber material;
5) adding the modified wheat straw fiber obtained in the step 4) into water for pulping and defibering, wherein the pulping degree is 22.0 DEG SR, and obtaining fiber pulp with the mass concentration of 2.4%;
6) adding silica fume and metakaolin into the fiber slurry obtained in the step 5), continuously shearing and dispersing for 10min, then adding dry materials prepared by mixing cement, fly ash and quartz sand and water to prepare mixed slurry, and controlling the water content of the mixed slurry to be more than or equal to 90%; and then preparing a wet blank by a forming process (a copying method), pre-curing for 4h at the temperature of 70 ℃, then performing autoclaved curing for 6h at the temperature of 180 ℃ and the pressure of 1.0MPa (controlling the water content of the plate blank obtained after the autoclaved curing to be less than or equal to 30%), and then drying at the temperature of 105 ℃ until the water content of the plate reaches below 7.0%, thus obtaining the asbestos-free straw fiber reinforced cement plate.
Example 3
The asbestos-free straw fiber reinforced cement board is mainly prepared from the following raw materials in parts by weight:
7.5 parts of modified wheat straw fiber, 5 parts of silica fume, 48 parts of cement, 12 parts of metakaolin, 22 parts of quartz sand and 5.5 parts of fly ash.
The preparation method of the asbestos-free straw fiber reinforced cement board comprises the following steps:
1) cutting dried wheat straws into short materials with the length of 20-40mm, soaking the short materials with clear water for 16h at room temperature to soften the short materials, then soaking the short materials with sodium hydroxide solution with the mass concentration of 3.0% for 20min, taking out the short materials, draining the short materials until water drops do not flow down as strands, and obtaining a prepared material;
2) placing the prepared material obtained in the step 1) in a steam explosion device for steam explosion, wherein the steam temperature is 180 ℃, the explosion pressure is 2.6MPa, the pressure maintaining time is 4.0min, and then discharging the material to obtain the explosive material;
3) soaking the blasting material obtained in the step 2) in a sodium hydroxide solution with the mass concentration of 2.0% for 2 hours, repeatedly rinsing with water until the blasting material is neutral and fibers are not adhered, and screening to obtain a fiber material with the length of 2-5 mm;
4) dissolving gamma-aminopropyltriethoxysilane in an ethanol water solution (the mass ratio of ethanol to water is 82:8) to prepare a modifier with the mass concentration of 10%, uniformly mixing the obtained modifier with the fiber material obtained in the step 3), and drying to remove ethanol (ethanol is recycled and reused) to obtain modified wheat straw fibers; wherein the dosage of the gamma-aminopropyl triethoxysilane is 1.2 percent of the mass of the fiber material;
5) adding the modified wheat straw fiber obtained in the step 4) into water for pulping and defibering, wherein the pulping degree is 23.0 DEG SR, and obtaining fiber pulp with the mass concentration of 2.6%;
6) adding silica fume and metakaolin into the fiber slurry obtained in the step 5), continuously shearing and dispersing for 10min, then adding dry materials prepared by mixing cement, fly ash and quartz sand and water to prepare mixed slurry, and controlling the water content of the mixed slurry to be more than or equal to 90%; then a wet blank is prepared by a forming process (a copying method), and the water content of the wet blank is controlled to be less than or equal to 32 percent; pre-curing for 3 hours at the temperature of 80 ℃, then performing autoclaved curing for 6 hours at the temperature of 175 ℃ and the pressure of 1.2MPa (controlling the water content of the plate blank obtained after the autoclaved curing to be less than or equal to 30%), and drying at the temperature of 105 ℃ until the water content of the plate reaches less than 7.0%, thus obtaining the asbestos-free straw fiber reinforced cement plate.
The asbestos-free stalk fiber reinforced cement boards obtained in examples 1-3 were prepared according to section 1 of JC/T412.1 fiber cement flat board: the results of the performance test conducted on the asbestos-free fiber cement slabs are shown in Table 1.
TABLE 1 results of performance test of asbestos-free straw fiber-reinforced cement boards obtained in examples 1 to 3
As can be seen from Table 1, the finished products of the asbestos-free straw fiber reinforced cement boards (raw boards) obtained in examples 1 to 3 have no phenomena of cracks, delamination, peeling and bubbling on the surface, have no obvious corner drop and edge drop, and meet the requirements of appearance quality; the design requirements for the thickness of the sheets of examples 1 to 3 were 10mm, and the apparent density of the sheets was 1.4g/cm2"ShiThe thickness and the apparent density in the actual measurement result are not lower than the design requirements, and the dimensional deviation is within the specified range. The detection shows that the water absorption rate of the obtained board is below 16.23 percent, and the wet expansion rate is below 0.13 percent, which shows that the combination between the wheat straw fiber reinforced material and the matrix in the asbestos-free straw fiber reinforced cement board is tighter, the porosity is small, the water absorption is difficult, and the water resistance and the moisture resistance are better; the incombustibility of the obtained plate meets the requirement of GB8624 incombustibility A, and after the water impermeability test lasts for 24 hours, no water drops appear on the bottom surface of the plate, so that the water impermeability requirement is met. In a mechanical property detection test, the water saturation breaking strength of the plate obtained in the examples 1-3 is respectively 13.26MPa, 13.52MPa and 13.89MPa, which are not lower than 13MPa, and the R3-level strength requirements of the A-type plate and the B-type plate are met; the impact strength is 1.97kJ/m respectively3、2.04kJ/m3、2.18kJ/m3Are not less than 1.8kJ/m3Meets the C3-grade strength requirement of the plate with the thickness e less than or equal to 14 mm. In an anti-freezing test, after 100 times of freeze-thaw cycles, the water-saturated breaking strength of the obtained plate is still more than 10.71MPa, the breaking strength ratio is more than 80.77%, the strength loss is small, and the plate has good anti-freezing performance; in a hot water test, the water saturation breaking strength of the obtained plate is still more than 9.89MPa, the breaking strength ratio is more than 74.26%, the strength loss is small, and the plate has good damp-heat resistance stability; in a soaking-drying test, the obtained board has the water saturation breaking strength of more than 11.38MPa, the breaking strength ratio of more than 84.67 percent, small strength loss and good dry and wet resistance stability.

Claims (9)

1. The asbestos-free straw fiber reinforced cement board is characterized in that: the health-care food is mainly prepared from the following raw materials in parts by weight:
6-8 parts of modified wheat straw fiber, 5-6 parts of silica fume, 48-52 parts of cement, 10-12 parts of metakaolin, 20-22 parts of quartz sand and 5-6 parts of fly ash;
wherein the modified wheat straw fiber is prepared by the method comprising the following steps:
1) cutting dried wheat straw into short materials, soaking in water for 12-16h for softening, and taking out to obtain the prepared material;
2) performing steam explosion on the prepared material obtained in the step 1), wherein the steam temperature is 175-180 ℃, the explosion pressure is 2.4-2.8MPa, the pressure maintaining time is 4.0-5.0min, and then discharging the material to obtain a blasting material;
3) soaking the blasting material obtained in the step 2) in a sodium hydroxide solution with the mass concentration of 1.0-2.0% for 2-3h, taking out and washing with water to obtain a fiber material;
4) dissolving gamma-aminopropyltriethoxysilane in an ethanol water solution to prepare a modifier, uniformly mixing the modifier with the fiber material obtained in the step 3), and drying to remove ethanol to obtain the modified wheat straw fiber.
2. The asbestos-free straw fiber reinforced cement board as claimed in claim 1, wherein: the particle size of the silica fume is 0.05-0.15 μm; the particle size of the metakaolin is 1-3 mu m; the particle size of the quartz sand is 200-300 meshes; the particle size of the fly ash is 300-500 meshes.
3. The asbestos-free straw fiber reinforced cement board as claimed in claim 1, wherein: in the step 1), the length of the short material is 20-40 mm.
4. The asbestos-free straw fiber reinforced cement board as claimed in claim 1, wherein: in the step 3), the water washing refers to repeatedly rinsing with water until the solution is neutral.
5. The asbestos-free straw fiber reinforced cement board as claimed in claim 1, wherein: in the step 4), the dosage of the gamma-aminopropyl triethoxysilane is 1.0-1.2% of the mass of the fiber material.
6. A method for preparing the asbestos-free straw fiber reinforced cement board as defined in any one of claims 1 to 5, wherein: the method comprises the following steps:
a) adding the modified wheat straw fiber with the formula amount into water for pulping and defibering, wherein the pulping degree is 20.0-25.0 DEG SR, and obtaining fiber pulp with the mass concentration of 2.4-2.6%;
b) adding silica fume and metakaolin into the fiber slurry obtained in the step a), continuously shearing and dispersing for 10-15min, then adding a dry material prepared by mixing cement, fly ash and quartz sand and water to prepare a mixed slurry, then preparing a wet blank through a forming process, and then performing pre-curing, autoclaved curing and drying to obtain the fiber slurry.
7. The method for preparing the asbestos-free straw fiber reinforced cement board as claimed in claim 6, wherein: in the step b), the temperature of the pre-curing is 60-80 ℃, and the time is 3-5 h; the temperature of the steam pressure curing is 175-185 ℃, the pressure is 0.8-1.2MPa, and the time is 6-8 h.
8. The method for preparing the asbestos-free straw fiber reinforced cement board as claimed in claim 6, wherein: in the step b), the water content of the mixed slurry is controlled to be more than or equal to 90%, the water content of the wet blank is controlled to be less than or equal to 32%, and the water content of the plate blank obtained after autoclaved curing is controlled to be less than or equal to 30%.
9. The method for preparing the asbestos-free straw fiber reinforced cement board as claimed in claim 6, wherein: in the step b), the drying temperature is 105-110 ℃, and the drying is carried out until the water content of the plate reaches below 7.0%.
CN202010107090.XA 2020-02-21 2020-02-21 Asbestos-free straw fiber reinforced cement board and preparation method thereof Withdrawn CN111217560A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010107090.XA CN111217560A (en) 2020-02-21 2020-02-21 Asbestos-free straw fiber reinforced cement board and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010107090.XA CN111217560A (en) 2020-02-21 2020-02-21 Asbestos-free straw fiber reinforced cement board and preparation method thereof

Publications (1)

Publication Number Publication Date
CN111217560A true CN111217560A (en) 2020-06-02

Family

ID=70826240

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010107090.XA Withdrawn CN111217560A (en) 2020-02-21 2020-02-21 Asbestos-free straw fiber reinforced cement board and preparation method thereof

Country Status (1)

Country Link
CN (1) CN111217560A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112010596A (en) * 2020-10-29 2020-12-01 佛山市东鹏陶瓷发展有限公司 Hydrophobic cement board and preparation method thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102633520A (en) * 2012-03-13 2012-08-15 江苏南瓷绝缘子有限公司 Method for quickly manufacturing foam cement heat-insulation plate
CN103086677A (en) * 2013-02-04 2013-05-08 青岛中镁建材有限公司 Novel cement fiberboard structure
CN103321376A (en) * 2013-06-20 2013-09-25 四川航天拓鑫玄武岩实业有限公司 Reinforced foam cement insulation and decoration integrated plate and manufacture method thereof
CN106278363A (en) * 2016-08-27 2017-01-04 欧振云 A kind of foam concrete heat-preserving plate
CN108439921A (en) * 2018-06-07 2018-08-24 魏浩峰 A kind of agricultural crop straw complex cement base insulating wall material and preparation method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102633520A (en) * 2012-03-13 2012-08-15 江苏南瓷绝缘子有限公司 Method for quickly manufacturing foam cement heat-insulation plate
CN103086677A (en) * 2013-02-04 2013-05-08 青岛中镁建材有限公司 Novel cement fiberboard structure
CN103321376A (en) * 2013-06-20 2013-09-25 四川航天拓鑫玄武岩实业有限公司 Reinforced foam cement insulation and decoration integrated plate and manufacture method thereof
CN106278363A (en) * 2016-08-27 2017-01-04 欧振云 A kind of foam concrete heat-preserving plate
CN108439921A (en) * 2018-06-07 2018-08-24 魏浩峰 A kind of agricultural crop straw complex cement base insulating wall material and preparation method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112010596A (en) * 2020-10-29 2020-12-01 佛山市东鹏陶瓷发展有限公司 Hydrophobic cement board and preparation method thereof
CN112010596B (en) * 2020-10-29 2021-03-02 佛山市东鹏陶瓷发展有限公司 Hydrophobic cement board and preparation method thereof

Similar Documents

Publication Publication Date Title
US8603231B2 (en) Phosphate bonded composites and methods
CN104692741B (en) A kind of stalk cellulose fiber/water cement-based composite material and preparation method thereof
TWI460339B (en) Panels including renewable components and methods for manufacturing
HU181185B (en) Method for producing bodies particularly auilding units
CN108439921B (en) Crop straw composite cement-based heat-insulating wall material and preparation method thereof
CN102584120B (en) Carbide slurry fly ash fiber-reinforced architectural flat plate and manufacturing method thereof
KR101991770B1 (en) Environmental friendly wood chip block, panel and the manufacturing method thereof
CN111217560A (en) Asbestos-free straw fiber reinforced cement board and preparation method thereof
CN107512924B (en) Wooden light building concrete and preparation method thereof
CN1944323A (en) Sound-proof heat insulation light wall
CN111205052A (en) Preparation method of asbestos-free plant fiber reinforced calcium silicate board and asbestos-free plant fiber reinforced calcium silicate board
CN111302685A (en) Preparation method of wheat straw fiber reinforced cement board and wheat straw fiber reinforced cement board
CN106273831A (en) A kind of hot-forming gangue building waste sheet material
CN106277971A (en) A kind of hot-forming alkaline residue building waste sheet material
CN107572951B (en) High-density calcium silicate board and preparation method thereof
WO2018193398A1 (en) Pressed board products
CN100392015C (en) Composite fiber plate and preparing method
CN102826786B (en) Light-weight fly ash fiber acoustic board and preparation method thereof
CN108484016B (en) Preparation method of biomass reinforced cement-based heat-insulating wall material and heat-insulating wall material
CN106277970A (en) A kind of hot-forming slag building waste sheet material
CN105236926A (en) Inorganic gluing non-wood plant wood based panel and preparation process thereof
CN108995318B (en) Paper gypsum board with high strength and low absorptivity
CN112159193A (en) Manufacturing method of fireproof calcium silicate board
CN107060161B (en) Rock wool board for building curtain wall
CN111718168A (en) Asbestos-free composite fiber reinforced calcium silicate board and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
WW01 Invention patent application withdrawn after publication

Application publication date: 20200602