CN108439921B - Crop straw composite cement-based heat-insulating wall material and preparation method thereof - Google Patents
Crop straw composite cement-based heat-insulating wall material and preparation method thereof Download PDFInfo
- Publication number
- CN108439921B CN108439921B CN201810582242.4A CN201810582242A CN108439921B CN 108439921 B CN108439921 B CN 108439921B CN 201810582242 A CN201810582242 A CN 201810582242A CN 108439921 B CN108439921 B CN 108439921B
- Authority
- CN
- China
- Prior art keywords
- cement
- fiber
- water
- washing
- wheat straw
- 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.)
- Active
Links
Classifications
-
- 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
-
- 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
- C04B20/00—Use 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
- C04B20/02—Treatment
- C04B20/023—Chemical treatment
-
- 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
- C04B20/00—Use 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
- C04B20/02—Treatment
- C04B20/026—Comminuting, e.g. by grinding or breaking; Defibrillating fibres other than asbestos
-
- 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
- C04B2111/27—Water resistance, i.e. waterproof or water-repellent materials
-
- 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
- C04B2111/29—Frost-thaw resistance
-
- 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
- C04B2111/40—Porous or lightweight materials
-
- 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
- C04B2111/52—Sound-insulating materials
-
- 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
- C04B2201/20—Mortars, concrete or artificial stone characterised by specific physical values for the density
-
- 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
- C04B2201/30—Mortars, concrete or artificial stone characterised by specific physical values for heat transfer properties such as thermal insulation values, e.g. R-values
- C04B2201/32—Mortars, concrete or artificial stone characterised by specific physical values for heat transfer properties such as thermal insulation values, e.g. R-values for the thermal conductivity, e.g. K-factors
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
- Dry Formation Of Fiberboard And The Like (AREA)
Abstract
The invention relates to a crop straw composite cement-based heat-insulating wall material and a preparation method thereof, wherein the heat-insulating wall material is prepared by the following steps: 1) cutting wheat straws, and performing steam explosion to obtain blasting materials; 2) washing the blasting material with water, immersing the washed material into NaOH solution, filtering, separating, washing and drying to obtain wheat straw fiber; 3) modifying the obtained wheat straw fiber with a silane coupling agent, adding metakaolin, stirring and mixing to obtain a fiber premix; 4) stirring and mixing the fiber premix with cement, polystyrene foam particles, a water reducing agent and water, and pouring and molding, standing and demolding and maintaining the obtained slurry to obtain the concrete. The obtained light heat-insulating wall material has low water absorption and high water absorption softening coefficient on the basis of ensuring good mechanical property and heat insulation performance; after 50 times of freeze-thaw cycles, the loss rate of the compressive strength is not more than 10%, the loss rate of the quality is not more than 5%, and the anti-freezing performance and the durability are good.
Description
Technical Field
The invention belongs to the technical field of cement-based heat-insulating wall materials, and particularly relates to a crop straw composite cement-based heat-insulating wall material and a preparation method thereof.
Background
The cement-based material is the most widely used building material at present, and makes a prominent contribution to the progress and development of the human society. However, cement-based materials suffer from the following problems due to the inherent defects of cement: the tensile strength is far lower than the compressive strength; is a typical brittle material, and has poor capability of resisting external impact; the crack resistance is poor, a large number of temperature cracks and drying cracks exist in the structure, and large cracks are gradually developed with the increase of service time, thereby seriously affecting the durability and safety of the structure.
In order to solve the problems, fibers are doped into the cement-based material for compounding to obtain the fiber-reinforced cement-based material. The fiber in the composite cement-based material mainly has the functions of improving the tensile strength and the deformability of the fiber and preventing the generation and the development of cracks. At present, the technology of asbestos fiber, steel fiber, synthetic fiber, glass fiber and the like as reinforcing materials is mature, but asbestos is toxic, and fiber dust is easy to cause harm to human health; the steel fiber is easy to rust in the cracks, so that the strength is influenced; synthetic fibers such as polypropylene fibers and the like need to be additionally added with an antioxidant, an ultraviolet-resistant stabilizer and a flame retardant, so that the cost is high; glass fibers are susceptible to alkaline corrosion in cement and are relatively costly. Therefore, there is a need to find new low cost fibers for reinforcing cementitious materials.
The crop straw is a renewable natural resource with wide source and large storage capacity, has large length-diameter ratio, higher strength, larger specific surface area and higher toughness, and is a natural composite material with a porous cell structure. The crop straw fiber is a low-cost green fiber, and is used as a reinforcing material of a cement matrix, so that on one hand, the bending strength and the fracture toughness of the cement matrix material can be improved, the density of the material is reduced, the structure and the mechanical property of the material are improved, the dry shrinkage cracks are inhibited, and the continuity of the matrix is ensured; on the other hand, the crop straw fiber has a pore structure, so that the composite material has good heat preservation and sound absorption effects. Therefore, the crop straw composite cement-based material is more and more paid attention by people.
However, calcium hydroxide generated in the cement hydration process can be dissolved in redundant water in pores of a matrix to form an alkaline solution, hemicellulose and lignin in fibers can be degraded due to the existence of the calcium hydroxide in the solution and an alkaline environment, so that the structure of the fibers is damaged, the strength and the toughness of the fibers are reduced, gaps are formed after the fiber structure is damaged, the calcium hydroxide enters the fibers to deposit and crystallize in the pores, so that the fibers are mineralized, the flexibility is lost, the fibers are easy to break, the durability of the composite material is poor, and the actual service life of the crop straw composite cement-based material is far shorter than the design service life of a building. When the crop straw composite cement-based material is used as a heat-insulating wall material, the maintenance and the replacement are required for two times or more, so that the use and heat-insulating effect are influenced, and the engineering quality is reduced; and the subsequent maintenance and replacement operation is increased, and the maintenance and repair cost is increased, so that the large-scale popularization and application of the composite material are limited.
Disclosure of Invention
The invention aims to provide a crop straw composite cement-based heat-insulating wall material, which improves the durability and quality stability of the material on the basis of ensuring the service performance of the material.
The second purpose of the invention is to provide a preparation method of the crop straw composite cement-based heat-insulating wall material.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a crop straw composite cement-based heat-insulating wall material is prepared by the following steps:
1) cutting wheat straws to a length of 20-40mm, then performing steam explosion at a steam temperature of 185-190 ℃, under a steam pressure of 2.8-3.0MPa and under a pressure maintaining time of 2.5-3.0min, and discharging under pressure to obtain a blasting material;
2) washing the blasting material obtained in the step 1) for the first time to obtain a washing material, immersing the washing material into a NaOH solution with the mass concentration of 0.8-1.2%, preserving the heat at the temperature of 60-80 ℃ for 1.5-2.5h, and then filtering, separating, washing for the second time and drying to obtain the wheat straw fiber;
3) modifying the wheat straw fibers obtained in the step 2) with a silane coupling agent, adding metakaolin, stirring and mixing, wherein the dosage of the silane coupling agent is 1.2-1.5% of the mass of the wheat straw fibers, and the dosage of the metakaolin is 2.0-2.5 times of the mass of the wheat straw fibers, and uniformly mixing to obtain a fiber premix;
4) stirring and mixing the fiber premix obtained in the step 3) with cement, polystyrene foam particles, a water reducing agent and water, wherein the amount of the fiber premix is 2.0-2.5% of the weight of the cement, the amount of the polystyrene foam particles is 26-30% of the weight of the cement, the water-glue ratio is 0.48-0.52, and the obtained slurry is subjected to pouring molding, standing demolding and curing to obtain the composite material.
In the step 1), the water content of the wheat straw is 35-40%.
In the step 2), the water washing refers to that the blasting material is immersed in water according to the solid-liquid mass ratio of 1 (4-5), the immersion time is 4-6h, and then the water washing material and the washing liquid are obtained by filtering and extruding for solid-liquid separation.
In the step 2), the water-washing material is immersed into NaOH solution, and the solid-liquid mass ratio of the water-washing material to the NaOH solution is 1 (4-5).
In the step 2), the drying temperature is 65-70 ℃, and the drying is carried out until the moisture content of the wheat straw fiber is not more than 15%.
In the step 3), the modification of the silane coupling agent refers to preparing a silane coupling agent solution, spraying the silane coupling agent solution on the surface of the wheat straw fiber, stirring to fully wet the surface of the fiber, and drying to remove the solvent. The solvent used for preparing the silane coupling agent solution is ethanol-water mixed solvent. The mass ratio of the silane coupling agent to the ethanol to the water is 20:72: 8.
The silane coupling agent is 3-aminopropyl triethoxysilane.
In the step 4), the water reducing agent is sodium lignosulfonate.
The dosage of the water reducing agent is 0.3-0.5% of the mass of the cement.
In the step 4), cement and polystyrene foam particles are mixed, then the fiber premix and a part of water are added for mixing, and then the water reducing agent aqueous solution is added for mixing to obtain slurry.
The preparation method of the crop straw composite cement-based heat-insulating wall material comprises the following steps:
1) cutting wheat straws to a length of 20-40mm, then performing steam explosion at a steam temperature of 185-190 ℃, under a steam pressure of 2.8-3.0MPa and under a pressure maintaining time of 2.5-3.0min, and discharging under pressure to obtain a blasting material;
2) washing the blasting material obtained in the step 1) for the first time to obtain a washing material, immersing the washing material into a NaOH solution with the mass concentration of 0.8-1.2%, preserving the heat at the temperature of 60-80 ℃ for 1.5-2.5h, and then filtering, separating, washing for the second time and drying to obtain the wheat straw fiber;
3) modifying the wheat straw fibers obtained in the step 2) with a silane coupling agent, adding metakaolin, stirring and mixing, wherein the dosage of the silane coupling agent is 1.2-1.5% of the mass of the wheat straw fibers, and the dosage of the metakaolin is 2.0-2.5 times of the mass of the wheat straw fibers, and uniformly mixing to obtain a fiber premix;
4) stirring and mixing the fiber premix obtained in the step 3) with cement, polystyrene foam particles, a water reducing agent and water, wherein the amount of the fiber premix is 2.0-2.5% of the weight of the cement, the amount of the polystyrene foam particles is 26-30% of the weight of the cement, the water-glue ratio is 0.48-0.52, and the obtained slurry is subjected to pouring molding, standing demolding and curing to obtain the composite material.
The crop straw composite cement-based heat-insulating wall material takes the wheat straw fiber as a reinforcing material, the content of cellulose substances playing a role of a mechanical structure in the wheat straw is high and reaches more than 60%, and the wheat straw composite cement-based heat-insulating wall material is relatively low in hemicellulose and lignin content and has relatively excellent mechanical strength, tensile property and stability. The wheat straws are pretreated by adopting a steam explosion process, on one hand, the straw raw materials are quickly heated to a set temperature by steam, the steam under high pressure diffuses and permeates into the fiber cell walls of the straws, and when the process is finished, the wet straw fibers are exploded due to sudden release of pressure and quick reduction of temperature, so that the purpose of separating and refining the fibers is achieved; on the other hand, through steam explosion treatment, hemicellulose in the straw fiber is degraded, lignin is activated, saccharides and acids are increased, macromolecular saccharides are decomposed into micromolecular saccharides, and water-soluble degraded saccharides are dissolved out and removed through primary water washing of the explosion material, so that the influence of the part of the substances on hydration and solidification of cement in a subsequent process is avoided, the wheat straw fiber is purified, and the cellulose content is improved.
When the wheat straw fiber is prepared, the water-washing material with water-soluble degraded carbohydrate substances removed is immersed in NaOH solution with a certain concentration, activated lignin in the water-washing material is extracted by heat preservation, and then the water-washing material is filtered, separated, washed for the second time and dried to obtain the purified wheat straw fiber. The cellulose content of the obtained wheat straw fiber is further improved, wherein most of relatively weak components, namely hemicellulose and lignin, are removed, and the cellulose component playing a main mechanical function in the wheat straw fiber is reserved and purified, so that on one hand, the wheat straw fiber is more refined, the fiber toughness is improved on the basis of maintaining the fiber strength, and the effects of improving the toughness and resisting cracking can be achieved by a small adding amount; on the other hand, the operation makes the fiber surface rough, improves the hydrophobicity of the fiber surface, and simultaneously, the combination surface of the fiber with rough surface and the matrix is larger, and the binding force is stronger.
When the crop straw composite cement-based heat-insulating wall material is prepared, most of hemicellulose and lignin in the wheat straw fiber, which are easily damaged by cement hydration alkaline environment, are removed, the obtained wheat straw fiber is subjected to surface modification by adopting a silane coupling agent, and the silane coupling agent is used for plugging and repairing surface pores and defects, so that the hydrophobic water resistance of the surface of the wheat straw fiber is further improved. Mixing the surface modified wheat straw fiber with metakaolin to obtain a premix, coating a layer of metakaolin dry material on the surface of the wheat straw fiber, stirring and mixing the mixture with cement, polystyrene foam particles, a water reducing agent and water, and generating Ca (OH) in the hydration process of the cement2Dissolving in water to form alkaline solution, allowing metakaolin coated on the surface of the wheat straw fiber to rapidly adsorb calcium hydroxide and react with the calcium hydroxide to generate a gel phase mixture of ettringite, calcium silicate and the like, curing the gel phase mixture into similar polymers to form a protective layer for connecting the wheat straw fiber and a cement matrix, and coating the wheat straw fiber to prevent alkaline environment from entering and corroding the wheat straw fiber. The metakaolin is used as a raw material, the gelation time of alkali excitation is short, the curing rate is high, the formed polymer is high in strength, the bonding strength with the wheat straw fiber and the cement matrix is high, the alkaline environment required by hydration and solidification of most of the cement matrix is not influenced, the mechanical property of the cement matrix is not greatly reduced, and the durability of the composite cement-based heat-insulating wall material is improved to the maximum extent on the basis of ensuring the basic mechanical property of the composite cement-based heat-insulating wall material.
Through detection, the dry apparent density of the crop straw composite cement-based heat-insulating wall material is 250kg/m3The light heat-insulating wall material belongs to the light heat-insulating wall material; the breaking strength, the compressive strength and the bonding strength respectively reach 1.43MPa, 2.70MPa and 64KPa, and the mechanical property is excellent; the thermal conductivity coefficient is as low as 0.039W/mKThe heat insulation performance is good; the sound insulation amount reaches 55dB, and the sound absorption and insulation effects are excellent; the drying linear shrinkage rate is small and is only 0.23-0.25, and the high-toughness and anti-cracking performance is achieved; low water absorption, high water absorption softening coefficient and good water resistance. As can be seen from a freeze-thaw cycle experiment for accelerated aging, after 50 times of freeze-thaw cycles, the crop straw composite cement-based heat-insulating wall material obtained by the invention has the advantages that the loss rate of compressive strength is not more than 10%, the loss rate of quality is not more than 5%, and good freezing resistance and durability are realized.
Detailed Description
The present invention will be further described with reference to the following embodiments.
In a specific embodiment, the cement used is P.O 42.5.5 Portland cement which is commercially available. The wheat straw is purchased from local farmers, and the water content is controlled to be 35-40%. The metakaolin is prepared by calcining metakaolin at 800 deg.C for 4 hr, has average particle diameter of not more than 1.0 μm, and specific gravity of 2.58g/cm3The activity is 35-40%. The polystyrene foam particles used have an average particle diameter of 2-5mm and an apparent density of 26.5kg/m3The stacking density is 9-10kg/m3. The water reducing agent is sodium lignosulfonate, and is a common water reducing agent sold in the market.
In the specific implementation mode, the steam explosion adopts a vertical cylindrical steam explosion device, when the device is used, straw small-section raw materials are fed into the device, then saturated steam is introduced, the internal pressure reaches the set pressure, the temperature is kept for the set time, a valve at the bottom of the device is opened, the materials are instantly sprayed into a receiver, and the straw raw materials are dissociated into fibers.
In the specific implementation mode, the silane coupling agent 3-aminopropyltriethoxysilane is dispersed in an ethanol-water mixed solvent to prepare a silane coupling agent solution, and the mass ratio of the silane coupling agent 3-aminopropyltriethoxysilane to ethanol to water is 20:72: 8.
Example 1
The crop straw composite cement-based heat-insulating wall material is prepared by the following method:
1) cutting wheat straw to length of 20-40mm, performing steam explosion at 185 deg.C under 2.8MPa for 3.0min, and discharging to obtain blasting material;
2) soaking the blasting material obtained in the step 1) into water at room temperature for 6 hours according to the solid-liquid mass ratio of 1:4, filtering and extruding to perform solid-liquid separation to obtain a primary washing material and a primary washing liquid;
soaking the obtained primary washing material into a NaOH solution with the mass concentration of 0.8% according to the solid-liquid mass ratio of 1:4, preserving the heat at 80 ℃ for 2.5h, filtering and separating, washing the material for the second time to be neutral, and drying at 65 ℃ until the water content is 15% to obtain the wheat straw fiber;
3) preparing a silane coupling agent 3-aminopropyltriethoxysilane into a solution, spraying the silane coupling agent solution on the surface of the wheat straw fiber obtained in the step 2), stirring to fully wet the surface of the fiber, continuously stirring, naturally ventilating and drying to remove the solvent, adding metakaolin, stirring and mixing, wherein the dosage of the silane coupling agent is 1.2% of the mass of the wheat straw fiber, and the dosage of the metakaolin is 2.0 times of the mass of the wheat straw fiber, and uniformly mixing to obtain a fiber premix;
4) dispersing a water reducing agent sodium lignosulfonate in water to prepare a solution; mixing and stirring cement and polystyrene foam particles for 40s, then adding the fiber premix obtained in the step 3) and water for mixing for 80s, and then adding a water reducing agent solution for mixing and stirring for 120s to obtain slurry;
wherein, based on the mass of the cement (100%), the mass of the other raw materials are as follows: 2.0 percent of fiber premix calculated by wheat straw fiber, 26 percent of polystyrene foam particles and 0.3 percent of water reducing agent; the water-to-glue ratio is 0.52;
pouring and molding the obtained slurry, standing and demolding for 24 hours, and performing standard maintenance (the humidity is 95% and the temperature is 20 ℃) to obtain the crop straw composite cement-based heat-insulation wall material.
Example 2
The crop straw composite cement-based heat-insulating wall material is prepared by the following method:
1) cutting wheat straw to length of 20-40mm, performing steam explosion at 190 deg.C under 3.0MPa for 2.5min, and discharging to obtain blasting material;
2) soaking the blasting material obtained in the step 1) into water at room temperature according to the solid-liquid mass ratio of 1:4.5 for 5h, filtering and extruding for solid-liquid separation to obtain a primary washing material and a primary washing liquid;
soaking the obtained primary washing material into a NaOH solution with the mass concentration of 1.0% according to the solid-liquid mass ratio of 1:4.5, preserving the heat at 70 ℃ for 2.0h, filtering and separating, washing the material for the second time to be neutral, and drying at 65 ℃ until the water content is 15% to obtain the wheat straw fiber;
3) preparing a silane coupling agent 3-aminopropyltriethoxysilane into a solution, spraying the silane coupling agent solution on the surface of the wheat straw fiber obtained in the step 2), stirring to fully wet the surface of the fiber, continuously stirring, naturally ventilating and drying to remove the solvent, adding metakaolin, stirring and mixing, wherein the dosage of the silane coupling agent is 1.4% of the mass of the wheat straw fiber, and the dosage of the metakaolin is 2.3 times of the mass of the wheat straw fiber, and uniformly mixing to obtain a fiber premix;
4) dispersing a water reducing agent sodium lignosulfonate in water to prepare a solution; mixing and stirring cement and polystyrene foam particles for 40s, then adding the fiber premix obtained in the step 3) and water for mixing for 80s, and then adding a water reducing agent solution for mixing and stirring for 120s to obtain slurry;
wherein, based on the mass of the cement (100%), the mass of the other raw materials are as follows: 2.2 percent of fiber premix calculated by wheat straw fiber, 28 percent of polystyrene foam particles and 0.4 percent of water reducing agent; the water-to-glue ratio is 0.50;
pouring and molding the obtained slurry, standing and demolding for 24 hours, and performing standard maintenance (the humidity is 95% and the temperature is 20 ℃) to obtain the crop straw composite cement-based heat-insulation wall material.
Example 3
The crop straw composite cement-based heat-insulating wall material is prepared by the following method:
1) cutting wheat straw to length of 20-40mm, performing steam explosion at 185 deg.C under 3.0MPa for 3.0min, and discharging to obtain blasting material;
2) soaking the blasting material obtained in the step 1) into water at room temperature for 4 hours according to the solid-liquid mass ratio of 1:5, filtering and extruding to perform solid-liquid separation to obtain a primary washing material and a primary washing liquid;
soaking the obtained primary washing material into a NaOH solution with the mass concentration of 1.2% according to the solid-liquid mass ratio of 1:5, preserving the heat at 60 ℃ for 1.5h, filtering and separating, washing the material for the second time to be neutral, and drying at 65 ℃ until the water content is 15% to obtain the wheat straw fiber;
3) preparing a silane coupling agent 3-aminopropyltriethoxysilane into a solution, spraying the silane coupling agent solution on the surface of the wheat straw fiber obtained in the step 2), stirring to fully wet the surface of the fiber, continuously stirring, naturally ventilating and drying to remove the solvent, adding metakaolin, stirring and mixing, wherein the dosage of the silane coupling agent is 1.5% of the mass of the wheat straw fiber, and the dosage of the metakaolin is 2.5 times of the mass of the wheat straw fiber, and uniformly mixing to obtain a fiber premix;
4) dispersing a water reducing agent sodium lignosulfonate in water to prepare a solution; mixing and stirring cement and polystyrene foam particles for 40s, then adding the fiber premix obtained in the step 3) and water for mixing for 80s, and then adding a water reducing agent solution for mixing and stirring for 120s to obtain slurry;
wherein, based on the mass of the cement (100%), the mass of the other raw materials are as follows: 2.5 percent of fiber premix calculated by wheat straw fiber, 30 percent of polystyrene foam particles and 0.5 percent of water reducing agent; the water-to-glue ratio is 0.48;
pouring and molding the obtained slurry, standing and demolding for 24 hours, and performing standard maintenance (the humidity is 95% and the temperature is 20 ℃) to obtain the crop straw composite cement-based heat-insulation wall material.
Experimental example 1
The experimental example tests the performance of the crop straw composite cement-based thermal insulation wall material obtained in examples 1-3, and the results are shown in table 1. Test specimens prepared according to the methods of examples 1-3 were tested at standard maintenance 28d age, and each set of values was tested in triplicate for each item and recorded as an average.
Table 1 results of testing performance of the crop straw composite cement-based thermal insulation wall material obtained in examples 1 to 3
As can be seen from Table 1, the dry apparent density of the crop straw composite cement-based thermal insulation wall material obtained in examples 1-3 is 250kg/m3The wheat straw fiber and polystyrene foam particles are added into the cement matrix, so that the density of the composite wall material is greatly reduced. The flexural strength, the compressive strength and the bonding strength of the crop straw composite cement-based heat-insulating wall material respectively reach 1.43MPa, 2.70MPa and 64KPa, and the mechanical property is excellent, the mechanical property is mainly generated by a cement matrix, the strength of the material is not reduced by excessive admixtures, the cellulose content of the used wheat straw fibers is high, and the mechanical strength of the composite wall material is not reduced excessively. The crop straw composite cement-based heat-insulating wall material has the heat conductivity coefficient as low as 0.039W/m.K, and has good heat-insulating performance; the sound insulation amount reaches 55dB, and the composite wall material has excellent sound absorption and sound insulation effects because the porosity and the porosity of the composite wall material are improved due to the incorporation of the wheat straw fibers and the polystyrene foam particles. The crop straw composite cement-based heat-insulating wall material has small dry linear shrinkage rate of only 0.23-0.25, and has good toughness and crack resistance; low water absorption, high water absorption softening coefficient and good water resistance. As can be seen from a freeze-thaw cycle experiment for accelerated aging, after 50 times of freeze-thaw cycles, the crop straw composite cement-based heat-insulating wall material obtained by the invention has the advantages that the loss rate of compressive strength is not more than 10%, the loss rate of quality is not more than 5%, and good freezing resistance and durability are realized.
Claims (8)
1. The crop straw composite cement-based heat-insulating wall material is characterized in that: the preparation method comprises the following steps:
1) cutting wheat straws to a length of 20-40mm, then performing steam explosion at a steam temperature of 185-190 ℃, under a steam pressure of 2.8-3.0MPa and under a pressure maintaining time of 2.5-3.0min, and discharging under pressure to obtain a blasting material;
2) washing the blasting material obtained in the step 1) for the first time to obtain a washing material, immersing the washing material into a NaOH solution with the mass concentration of 0.8-1.2%, preserving the heat at the temperature of 60-80 ℃ for 1.5-2.5h, and then filtering, separating, washing for the second time and drying to obtain the wheat straw fiber;
3) modifying the wheat straw fibers obtained in the step 2) with a silane coupling agent, adding metakaolin, stirring and mixing, wherein the dosage of the silane coupling agent is 1.2-1.5% of the mass of the wheat straw fibers, and the dosage of the metakaolin is 2.0-2.5 times of the mass of the wheat straw fibers, and uniformly mixing to obtain a fiber premix;
4) stirring and mixing the fiber premix obtained in the step 3) with cement, polystyrene foam particles, a water reducing agent and water, wherein the amount of the fiber premix is 2.0-2.5% of the weight of the cement, the amount of the polystyrene foam particles is 26-30% of the weight of the cement, the water-glue ratio is 0.48-0.52, and the obtained slurry is subjected to pouring molding, standing demolding and curing to obtain the composite material.
2. The crop straw composite cement-based thermal insulation wall material as claimed in claim 1, wherein: in the step 1), the water content of the wheat straw is 35-40%.
3. The crop straw composite cement-based thermal insulation wall material as claimed in claim 1, wherein: in the step 2), the water washing refers to that the blasting material is immersed in water according to the solid-liquid mass ratio of 1 (4-5), the immersion time is 4-6h, and then the water washing material and the washing liquid are obtained by filtering and extruding for solid-liquid separation.
4. The crop straw composite cement-based thermal insulation wall material as claimed in claim 1, wherein: in the step 3), the modification of the silane coupling agent refers to preparing a silane coupling agent solution, spraying the silane coupling agent solution on the surface of the wheat straw fiber, stirring to fully wet the surface of the fiber, and drying to remove the solvent.
5. The crop straw composite cement-based thermal insulation wall material as claimed in claim 4, wherein: the silane coupling agent is 3-aminopropyl triethoxysilane.
6. The crop straw composite cement-based thermal insulation wall material as claimed in claim 1, wherein: in the step 4), the water reducing agent is sodium lignosulfonate.
7. The crop straw composite cement-based thermal insulation wall material as claimed in claim 6, wherein: the dosage of the water reducing agent is 0.3-0.5% of the mass of the cement.
8. A method for preparing the crop straw composite cement-based thermal insulation wall material as claimed in any one of claims 1 to 7, wherein: the method comprises the following steps:
1) cutting wheat straws to a length of 20-40mm, then performing steam explosion at a steam temperature of 185-190 ℃, under a steam pressure of 2.8-3.0MPa and under a pressure maintaining time of 2.5-3.0min, and discharging under pressure to obtain a blasting material;
2) washing the blasting material obtained in the step 1) for the first time to obtain a washing material, immersing the washing material into a NaOH solution with the mass concentration of 0.8-1.2%, preserving the heat at the temperature of 60-80 ℃ for 1.5-2.5h, and then filtering, separating, washing for the second time and drying to obtain the wheat straw fiber;
3) modifying the wheat straw fibers obtained in the step 2) with a silane coupling agent, adding metakaolin, stirring and mixing, wherein the dosage of the silane coupling agent is 1.2-1.5% of the mass of the wheat straw fibers, and the dosage of the metakaolin is 2.0-2.5 times of the mass of the wheat straw fibers, and uniformly mixing to obtain a fiber premix;
4) stirring and mixing the fiber premix obtained in the step 3) with cement, polystyrene foam particles, a water reducing agent and water, wherein the amount of the fiber premix is 2.0-2.5% of the weight of the cement, the amount of the polystyrene foam particles is 26-30% of the weight of the cement, the water-glue ratio is 0.48-0.52, and the obtained slurry is subjected to pouring molding, standing demolding and curing to obtain the composite material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810582242.4A CN108439921B (en) | 2018-06-07 | 2018-06-07 | Crop straw composite cement-based heat-insulating wall material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810582242.4A CN108439921B (en) | 2018-06-07 | 2018-06-07 | Crop straw composite cement-based heat-insulating wall material and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108439921A CN108439921A (en) | 2018-08-24 |
| CN108439921B true CN108439921B (en) | 2021-02-12 |
Family
ID=63206752
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810582242.4A Active CN108439921B (en) | 2018-06-07 | 2018-06-07 | Crop straw composite cement-based heat-insulating wall material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108439921B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111302685A (en) * | 2020-02-21 | 2020-06-19 | 郑州知淘信息科技有限责任公司 | Preparation method of wheat straw fiber reinforced cement board and wheat straw fiber reinforced cement board |
| CN111217560A (en) * | 2020-02-21 | 2020-06-02 | 郑州知淘信息科技有限责任公司 | Asbestos-free straw fiber reinforced cement board and preparation method thereof |
| CN111718168A (en) * | 2020-03-04 | 2020-09-29 | 郑州知淘信息科技有限责任公司 | Asbestos-free composite fiber reinforced calcium silicate board and preparation method thereof |
| CN111205052A (en) * | 2020-03-04 | 2020-05-29 | 郑州知淘信息科技有限责任公司 | Preparation method of asbestos-free plant fiber reinforced calcium silicate board and asbestos-free plant fiber reinforced calcium silicate board |
| CN112408887A (en) * | 2020-12-04 | 2021-02-26 | 哈尔滨工业大学 | Preparation method of vibration-damping sound-insulating material based on agricultural waste recycling |
| CN112592135A (en) * | 2020-12-26 | 2021-04-02 | 成都拓凝舟涂料科技有限公司 | Preparation method of cement-based wall material |
| CN112456925A (en) * | 2021-01-13 | 2021-03-09 | 上海多茂建筑科技有限公司 | Erosion-resistant concrete with self-healing capability |
| CN115010401B (en) * | 2022-06-07 | 2023-08-01 | 四川省雍景投资集团有限责任公司 | Environment-friendly heat-preservation wallboard and preparation method thereof |
| CN115159910B (en) * | 2022-09-07 | 2022-12-06 | 广东潮泰建设有限公司 | Preparation method and application of high-strength waterproof concrete for building construction |
| CN115488996B (en) * | 2022-10-31 | 2023-06-27 | 东北林业大学 | Preparation method of modified wood chip reinforced cement-based composite material |
| CN115819038A (en) * | 2022-11-17 | 2023-03-21 | 金松果新材料科技有限公司 | Straw composite wall material and preparation method thereof |
| CN117209246B (en) * | 2023-10-19 | 2024-06-21 | 江苏宇航板业有限公司 | Production process of silica-calcium gel water-absorbing foot pad |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1295045A (en) * | 2000-11-20 | 2001-05-16 | 盛忠章 | Benzene containing cement board and its production process |
| CN105399383A (en) * | 2015-12-15 | 2016-03-16 | 冯丹 | Lightweight antifreezing straw fiber thermal insulation wallboard and manufacturing method therefor |
| CN107915431A (en) * | 2017-10-23 | 2018-04-17 | 安徽展大生物科技有限公司 | A kind of stalk brick of high intensity and preparation method thereof |
| CN107935467A (en) * | 2017-11-14 | 2018-04-20 | 成都新柯力化工科技有限公司 | A kind of stalk fibre pervious concrete and preparation method |
-
2018
- 2018-06-07 CN CN201810582242.4A patent/CN108439921B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1295045A (en) * | 2000-11-20 | 2001-05-16 | 盛忠章 | Benzene containing cement board and its production process |
| CN105399383A (en) * | 2015-12-15 | 2016-03-16 | 冯丹 | Lightweight antifreezing straw fiber thermal insulation wallboard and manufacturing method therefor |
| CN107915431A (en) * | 2017-10-23 | 2018-04-17 | 安徽展大生物科技有限公司 | A kind of stalk brick of high intensity and preparation method thereof |
| CN107935467A (en) * | 2017-11-14 | 2018-04-20 | 成都新柯力化工科技有限公司 | A kind of stalk fibre pervious concrete and preparation method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108439921A (en) | 2018-08-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108439921B (en) | Crop straw composite cement-based heat-insulating wall material and preparation method thereof | |
| CN108484016B (en) | Preparation method of biomass reinforced cement-based heat-insulating wall material and heat-insulating wall material | |
| CN104692741B (en) | A kind of stalk cellulose fiber/water cement-based composite material and preparation method thereof | |
| CN111217560A (en) | Asbestos-free straw fiber reinforced cement board and preparation method thereof | |
| CN114436601A (en) | Recycled aggregate self-compacting concrete and preparation method thereof | |
| CN104926260B (en) | Inorganic fire-proof light aggregate expanded perlite heat retaining board and preparation method thereof | |
| CN111205052A (en) | Preparation method of asbestos-free plant fiber reinforced calcium silicate board and asbestos-free plant fiber reinforced calcium silicate board | |
| CN107417202A (en) | A kind of foam concrete of wall laminboard layer and its preparation method and application | |
| Feng et al. | Study on properties and durability of alkali activated rice straw fibers cement composites | |
| US20140352578A1 (en) | Compositions and Methods For Making of a Concrete-Like Material Containing Cellulosic Derivatives | |
| Rahimi et al. | Effectiveness of treated flax fibers in improving the early age behavior of high-performance concrete | |
| CN113968700A (en) | High-toughness high-strength low-wet-expansion fiber cement external wall panel and preparation method thereof | |
| Omoniyi et al. | Durability based suitability of bagasse cement composite for roofing sheets | |
| CN108264254B (en) | Preparation process of modified rubber particles for rubber concrete | |
| Cigasova et al. | Influence of binder nature on properties of lightweight composites based on hemp hurds | |
| Jiang et al. | Effect of Straw Fiber Modification Methods on Compatibility between Straw Fibers and Cement‐Based Materials | |
| CN111393080B (en) | High-performance cementing material and preparation method thereof | |
| CN111302685A (en) | Preparation method of wheat straw fiber reinforced cement board and wheat straw fiber reinforced cement board | |
| CN113277770B (en) | Preparation method and application of modified flax fiber with enhancement effect | |
| Wang et al. | Investigation of the adaptability of paper sludge with wood fiber in cement-based insulation mortar | |
| Zheng et al. | Effect of the Proportion of Bamboo Scraps on the Properties of Bamboo Scraps/Magnesium Oxychloride Composites | |
| Cheng-Yong et al. | Durability of natural fiber-reinforced alkali-activated composites | |
| Hancharoen et al. | Enhancement of Thermal and Sound Insulation Properties of Cement Composite Roofing Tile by Addition of Nanocellulose Coated Pineapple Fiber and Modified Rubber Tire Waste | |
| CN117303854B (en) | Production process of light SMC composite wallboard | |
| Fonseca et al. | Influence of Different Types of Treatments on Amazonian Vegetable Fibers on the Performance of Mortars Based on Portland Cement, Metakaolin and Fly Ash |
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 | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20210120 Address after: 518045 5th floor, Lianxing warehouse building, No.4, HongMian Road, Fubao community, Fubao street, Futian District, Shenzhen City, Guangdong Province (501-503, 5th floor, zhicube Innovation Park) Applicant after: SHENZHEN SINO STRUCTURE CONSTRUCTION ENGINEERING Co.,Ltd. Address before: 450000 No. 32, west slope, Wuluo village, West Village, Gongyi City, Zhengzhou, Henan Applicant before: Wei Haofeng |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant |