CN114656218A - Anti-crack concrete with low shrinkage rate and preparation method thereof - Google Patents
Anti-crack concrete with low shrinkage rate and preparation method thereof Download PDFInfo
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- CN114656218A CN114656218A CN202210412873.8A CN202210412873A CN114656218A CN 114656218 A CN114656218 A CN 114656218A CN 202210412873 A CN202210412873 A CN 202210412873A CN 114656218 A CN114656218 A CN 114656218A
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B1/00—Producing shaped prefabricated articles from the material
- B28B1/08—Producing shaped prefabricated articles from the material by vibrating or jolting
- B28B1/087—Producing shaped prefabricated articles from the material by vibrating or jolting by means acting on the mould ; Fixation thereof to the mould
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B1/00—Producing shaped prefabricated articles from the material
- B28B1/52—Producing shaped prefabricated articles from the material specially adapted for producing articles from mixtures containing fibres, e.g. asbestos cement
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B14/38—Fibrous materials; Whiskers
- C04B14/46—Rock wool ; Ceramic or silicate fibres
- C04B14/4643—Silicates other than zircon
-
- 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
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/34—Non-shrinking or non-cracking materials
- C04B2111/343—Crack resistant materials
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
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- 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
Abstract
The application relates to concrete, in particular to anti-crack concrete with low shrinkage and a preparation method thereof, wherein the anti-crack concrete comprises the following raw materials in parts by weight: 100-150 parts of water, 80-120 parts of cement, 50-90 parts of silica sand, 40-80 parts of fly ash, 50-80 parts of limestone, 20-40 parts of reinforcing fiber and 5-8 parts of water reducing agent; the reinforcing fibers comprise modified basalt fibers; the preparation method of the modified basalt fiber comprises the following steps: 1): soaking basalt fibers in acid liquor, taking out, washing to be neutral, and drying to obtain pretreated fibers; 2): taking a rare earth solution, placing the pretreated fiber prepared in the step 1) in the rare earth solution, soaking for 2-3h, taking out and drying to obtain the fiber. The method has the advantage of improving the cracking resistance of the anti-cracking concrete with low shrinkage.
Description
Technical Field
The application relates to the field of concrete, in particular to anti-crack concrete with low shrinkage rate and a preparation method thereof.
Background
At present, in the period of rapid economic development in China, the amount of engineering for infrastructure is huge, a large amount of concrete is needed, the concrete is a composite material formed by taking cement as a cementing material and taking sand and stone as aggregates for cementing, the concrete is subjected to volume reduction in the early setting stage or the hardening process and generally comprises plastic shrinkage, chemical shrinkage, drying shrinkage and carbonization shrinkage, the concrete is cracked due to large shrinkage, and when the cracking degree is large, the quality of the prepared concrete is influenced, so that the quality of the infrastructure engineering is influenced, the shrinkage performance of the concrete is reduced, and the reduction of the cracking of the concrete becomes the main direction of current research.
In the above-described related art, the inventors consider that: the cracking resistance of the existing anti-cracking concrete with low shrinkage rate needs to be improved.
Disclosure of Invention
In order to improve the cracking resistance of the anti-cracking concrete with low shrinkage rate, the application provides the anti-cracking concrete with low shrinkage rate and a preparation method thereof.
In a first aspect, the application provides an anti-crack concrete with low shrinkage, which adopts the following technical scheme:
the anti-crack concrete with low shrinkage comprises the following raw materials in parts by weight: 100-150 parts of water, 80-120 parts of cement, 50-90 parts of silica sand, 40-80 parts of fly ash, 50-80 parts of limestone, 20-40 parts of reinforcing fiber and 5-8 parts of water reducing agent; the reinforcing fibers comprise modified basalt fibers; the preparation method of the modified basalt fiber comprises the following steps:
1): soaking basalt fibers in acid liquor, taking out, washing to be neutral, and drying to obtain pretreated fibers;
2): taking a rare earth solution, placing the pretreated fiber prepared in the step 1) in the rare earth solution, soaking for 2-3h, taking out and drying to obtain the fiber.
By adopting the technical scheme, water, cement, silica sand, fly ash, limestone, reinforcing fiber and a water reducing agent are mixed together to prepare the anti-crack concrete with low shrinkage; because the reinforced fibers comprise the modified basalt fibers, the basalt fibers have excellent performances of high strength, corrosion resistance and high temperature resistance; in the process of drying the anti-crack concrete with low shrinkage rate, due to the evaporation of water, the concrete can be subjected to certain drying shrinkage, cracks can be generated in the process, basalt fibers are added into the concrete, when the anti-crack concrete with low shrinkage rate is subjected to drying shrinkage to generate cracks, the shrinkage force generated by the drying shrinkage is transmitted to the basalt fibers, and the basalt fibers crossing the cracks can play a certain role in resisting the generation of the cracks, so that the generation of the cracks in the anti-crack concrete with low shrinkage rate is reduced, and the anti-crack performance of the prepared anti-crack concrete with low shrinkage rate can be effectively improved; but the basalt fiber has the characteristics of smoothness and poor activity, and has low interface bonding performance with other raw materials after being added into anti-crack concrete with low shrinkage rate, so that the basalt fiber needs to be modified, the basalt fiber is soaked by acid liquor, the surface of the basalt fiber is etched by the acid liquor, so that a speckled protruding structure is generated on the smooth basalt fiber surface, the roughness of the basalt fiber surface is improved, the subsequent contact area between the basalt fiber and a rare earth solution is increased, a large amount of rare earth atoms are adsorbed to the surface of the basalt fiber in the soaking process of the rare earth solution, a rare earth film is formed to wrap the surface of the basalt fiber, the rare earth atoms in the rare earth film can perform coordination chemical reaction with organic active groups in the concrete raw materials, and the content of the organic active groups on the surface of the modified basalt fiber is increased, and the binding force between the modified basalt fiber and other raw materials in the anti-crack concrete with low shrinkage is improved, the dry cracking resistance of the modified basalt fiber to the anti-crack concrete with low shrinkage is improved, and the strength of the prepared anti-crack concrete with low shrinkage is improved.
Preferably, the rare earth solution in the step 2) is prepared from lanthanum chloride and water according to a mass ratio of (0.1-0.9): (95-105).
By adopting the technical scheme, the mass ratio of lanthanum chloride to water is adjusted, so that the concentration of the rare earth solution is adjusted, along with the gradual increase of the concentration of the rare earth solution, the carbon element on the surface of the pretreated fiber is obviously reduced, the oxygen element and the nitrogen element show a growing trend, the active group on the surface of the pretreated fiber is gradually increased at the moment, when the concentration of the rare earth solution is overlarge, the active group formed on the surface of the pretreated fiber before can be damaged by the rare earth solution with overhigh concentration, and meanwhile, a large number of rare earth atoms are adsorbed on the surface of the pretreated fiber, so that a part of large granular structure is formed on the rare earth film on the surface of the pretreated fiber, the organic active group on the surface of the pretreated fiber reaches a saturated state, and the rare earth film is swelled or even broken under the action of tension, and the active group on the surface of the pretreated fiber is reduced; therefore, the bonding performance of the modified basalt fiber and other raw materials is reduced, so that when the basalt fiber is treated by the rare earth solution, the number of active groups on the surface of the modified basalt fiber and the bonding performance in the anti-crack concrete with low shrinkage rate can be improved by adjusting the concentration of the rare earth solution, and the modified basalt fiber can stably play a role in anti-crack performance of the anti-crack concrete with low shrinkage rate.
Preferably, after the pretreated fiber in the step 2) is immersed in the rare earth solution, ultrasonic oscillation is simultaneously carried out for 20-30min in the immersion process.
By adopting the technical scheme, the basalt fiber is treated by the acid liquor, the surface of the basalt fiber is in an uneven state, and when the pretreated fiber is placed in the rare earth solution for dipping, rare earth atoms are easy to accumulate at the concave part of the surface of the pretreated fiber, so that the dispersion uniformity of a rare earth film on the surface of the pretreated fiber is influenced; the ultrasonic oscillation mode is adopted to carry out ultrasonic oscillation on the pretreated fiber and the rare earth solution, so that rare earth atoms in the rare earth solution can be more uniformly dispersed and combined on the pretreated fiber, the uniformity of a rare earth film formed on the surface of the pretreated fiber is enhanced, meanwhile, the distribution of active groups on the surface of the modified basalt fiber is more uniform, the modified basalt fiber can be more firmly combined with other raw materials in the anti-crack concrete with low shrinkage rate, and the anti-crack effect of the modified basalt fiber on the anti-crack concrete with low shrinkage rate is improved.
Preferably, the reinforcing fibers are prepared from modified basalt fibers, polyvinyl alcohol fibers and polypropylene fibers according to a mass ratio of (3-5): (2-4).
By adopting the technical scheme, the polyvinyl alcohol fiber or the polypropylene fiber and the modified basalt fiber are mixed to form the reinforced fiber, and the polypropylene fiber and other raw materials in the concrete have good cohesiveness, so that when the crack-resistant concrete with low shrinkage rate is dried and shrunk, cracks in the concrete gradually expand, and in the expansion process of the cracks, the polypropylene fiber and the polyvinyl alcohol fiber can provide enough bridging stress, resist the stress and deformation at the tip of the cracks and resist the formation of the cracks; meanwhile, the polyvinyl alcohol fibers and the polypropylene fibers can be distributed in a disorderly manner in the anti-crack concrete with low shrinkage rate to form a three-dimensional grid, the three-dimensional grid can bear the internal stress borne by the anti-crack concrete with low shrinkage rate in use, and the compressive strength of the anti-crack concrete with low shrinkage rate is enhanced, so that the cracking phenomenon of the anti-crack concrete with low shrinkage rate in use is reduced.
Preferably, the reinforcing fibers are prepared from modified basalt fibers, polyvinyl alcohol fibers and polypropylene fibers according to a mass ratio of (3-5): (1-2): (1-2).
By adopting the technical scheme, the polyvinyl alcohol fiber has the characteristics of high strength modulus, wear resistance, acid and alkali resistance, and good affinity and binding force with base materials such as cement, gypsum and the like, and also has the characteristics of no toxicity and no pollution, and can improve the toughness and strength of the polyvinyl alcohol fiber when being added into anti-crack concrete with low shrinkage; the polypropylene fiber has the advantages of light weight, good strength, good elasticity, wear resistance and corrosion resistance, and has better toughness compared with polyvinyl alcohol fiber; therefore, the modified basalt fiber, the polyvinyl alcohol fiber and the polypropylene fiber are mixed together and added into the anti-crack concrete with low shrinkage rate, so that the performance of the anti-crack concrete with low shrinkage rate can be improved at different structural levels and different performance levels, the size effect and the performance effect of the reinforcing fiber can be fully exerted, and the anti-crack performance of the prepared anti-crack concrete with low shrinkage rate is improved.
In a second aspect, the present application provides a method for preparing an anti-crack concrete with a low shrinkage rate, which adopts the following technical scheme:
a preparation method of anti-crack concrete with low shrinkage rate comprises the following steps:
s1: mixing reinforced fiber, cement, silica sand, fly ash and limestone together to prepare a premix;
s2: adding water and a water reducing agent into the premix prepared in the step S1 together, and uniformly mixing to prepare a compound material;
s3: and (5) placing the compound mixture prepared in the step S2 into a mould, vibrating and molding, demoulding and maintaining to obtain the material.
By adopting the technical scheme, the reinforced fiber, the cement, the silica sand, the fly ash and the limestone are mixed together to prepare a premix, and then water and the water reducing agent are added; because the reinforcing fibers are light in weight and easy to tangle, the reinforcing fibers are mixed with the dry materials, so that the reinforcing fibers can be fully mixed with cement, silica sand, fly ash and limestone and are uniformly distributed in the prepared premix, and the reinforcing fibers are prevented from being stacked when meeting water; and then adding water and a water reducing agent, and carrying out hydration reaction on cement in the stirring process, so that the reinforcing fibers can be uniformly distributed and bonded in the prepared anti-crack concrete with low shrinkage rate, and the reinforcing fibers can stably play an anti-crack effect on the anti-crack concrete with low shrinkage rate.
Optionally, in step S1, 20 to 30 parts of waste glass powder is further added before the reinforcing fiber, cement, silica sand, fly ash and limestone are mixed.
By adopting the technical scheme, the main chemical component of the waste glass powder is SiO2、Na2O, CaO and Al2O3After the waste glass powder is added into the anti-crack concrete with low shrinkage rate, the activity of the waste glass powder can be excited under the action of cement hydration products because the early activity of the waste glass powder is relatively low, and C-S-H gel and hydrogen are generated in the cement hydration processCalcium oxide and waste glass powder can jointly generate volcanic ash reaction with calcium hydroxide to promote SiO in the waste glass powder2The Si-O bond in the anti-crack concrete is decomposed, meanwhile, the waste glass powder can be subjected to hydration reaction with calcium hydroxide to generate insoluble C-S-H gel, hydrated calcium aluminate gel and other products, the C-S-H gel and the hydrated calcium aluminate gel can improve the bonding strength of all raw materials in the anti-crack concrete with low shrinkage rate, improve the compactness of the anti-crack concrete with low shrinkage rate and reduce cracking of the anti-crack concrete with low shrinkage rate caused by shrinkage.
Optionally, the particle size of the waste glass powder added in the step S1 is 800-400 meshes.
By adopting the technical scheme, the particle size of the waste glass powder is adjusted, under the condition of the same addition amount, the smaller the particle size of the waste glass powder is, the more sufficient the coverage surface of the waste glass powder added into the anti-crack concrete with low shrinkage rate is, but in the early curing process of the anti-crack concrete with low shrinkage rate, the hydrate surface of the gel material generated in the anti-crack concrete with low shrinkage rate has more holes, when the particle size of the waste glass powder is too small, the effect of filling the holes on the surface of the gel material is not obvious, so that the compactness of the prepared anti-crack concrete with low shrinkage rate is reduced, the anti-crack concrete with low shrinkage rate is easy to crack when being dried, and the strength of the anti-crack concrete with low shrinkage rate is influenced; however, when the particle size of the waste glass powder is too large, the waste glass powder is easy to aggregate in the anti-crack concrete with low shrinkage rate, the overall porosity of hydrate is not reduced, the compactness of the prepared anti-crack concrete with low shrinkage rate is influenced, and the prepared anti-crack concrete with low shrinkage rate is easy to crack due to shrinkage when being dried; therefore, the density of the prepared anti-cracking concrete with low shrinkage is improved by adjusting the particle size of the waste glass powder, and the cracking phenomenon of the anti-cracking concrete with low shrinkage in the drying process is reduced.
Optionally, after the water and the water reducing agent are added to the premix prepared in the step S1 in the step S1, 10 to 20 parts of a reinforcing resin is added before mixing; the reinforced resin is prepared from epoxy resin and a curing agent according to the mass ratio (7-10): (1-2).
By adopting the technical scheme, the reinforced resin which is composed of the epoxy resin and the curing agent is added, and because the basalt fiber is modified by the rare earth solution, oxygen-containing groups such as hydroxyl, carbonyl, carboxyl and other active groups are introduced on the surface of the basalt fiber, and the active groups improve the bonding performance of the modified basalt fiber and the epoxy resin; meanwhile, in the modification process, the surface of the basalt fiber is subjected to the etching action of the acid liquor, so that the surface area of the basalt fiber is increased, the friction force between the prepared modified basalt fiber and the epoxy resin is increased, the basalt fiber is contacted with the epoxy resin to generate an anchoring effect, the bonding strength between the epoxy resin and the modified basalt fiber is improved, and the cracking resistance of the prepared anti-cracking concrete with low shrinkage rate is improved; meanwhile, when the concentration of the rare earth solution is low, rare earth atoms adsorbed on the surface of the modified basalt fiber are few, the rare earth atoms are not arranged tightly on the surface of the basalt fiber, and a hole is formed in the middle of the basalt fiber, so that the modified basalt fiber and the epoxy resin cannot be connected tightly, when the anti-crack concrete with low shrinkage is acted by external force, the modified basalt fiber and the epoxy resin are easy to separate, and the anti-cracking effect of the modified basalt fiber on the anti-crack concrete with low shrinkage is influenced; when the concentration of the rare earth solution is too high, a large number of rare earth atoms can be gathered on the surface of the basalt fiber to form a multi-layer rare earth atomic layer structure, the multi-layer rare earth atomic layers are combined by weak van der Waals force, and when the anti-crack concrete with low shrinkage rate is subjected to external force, the van der Waals force between the rare earth atomic layers can be damaged, so that the bonding force between the modified basalt fiber and the epoxy resin is reduced, and the anti-crack performance of the anti-crack concrete with low shrinkage rate is influenced.
In summary, the present application has the following beneficial effects:
according to the method, modified basalt fibers are added into the prepared anti-crack concrete with low shrinkage rate, and in the modification process of the basalt fibers, the surfaces of the basalt fibers are etched by acid liquor, so that the roughness of the basalt fibers is increased, and the pretreatment fibers are prepared; and then mixing the pretreated fiber with a rare earth solution, wherein rare earth atoms form a rare earth film to wrap the surface of the basalt fiber, so that the content of organic active groups on the surface of the prepared modified basalt fiber is increased, the binding force between the modified basalt fiber and other raw materials in the anti-crack concrete with low shrinkage is improved, and the anti-crack effect of the modified basalt fiber on the anti-crack concrete with low shrinkage is improved.
Detailed Description
The present application will be described in further detail with reference to examples;
the cement used in the application is commercially available portland cement, and the 28-day compressive strength of the cement is not less than 52.5 MPa;
the silica sand is commercially available silica sand for concrete, and has a bulk density of 1850kg/m3；
The fly ash used in the method is commercially available fly ash for concrete, and the particle size of the fly ash used in the method is 200 meshes;
the limestone used has a bulk density of 1250kg/m3；
The used reinforcing fibers comprise modified basalt fibers, polyvinyl alcohol fibers and polypropylene fibers, and the compressive strength of the basalt fibers used in the application is 1050 Mpa;
the water reducing agent is a commercial polycarboxylic acid water reducing agent, and the purity is 99 percent;
the polyvinyl alcohol fiber is commercially available polyvinyl alcohol fiber for concrete, and the breaking strength is 1200 MPa;
the polypropylene fiber is commercially available polypropylene fiber for concrete, and the breaking strength is 560 MPa;
when the basalt fiber is modified, the acid solution is a nitric acid solution with the mass fraction of 37%;
the rare earth solution is formed by mixing lanthanum chloride and water; the CAS number of the lanthanum chloride is 10099-58-8;
the preparation method of the waste glass powder comprises the following steps: classifying, cleaning and drying colorless glass bottles, crushing, putting the glass bottles into a grinder to be ground into powder, taking the ground powder, sieving the powder by a 800-mesh sieve, and taking undersize products to obtain waste glass powder with the particle size of 800 meshes;
continuously taking the ground powder, sieving the powder by a 400-mesh sieve, and taking undersize to obtain waste glass powder with the particle size of 400 meshes;
continuously taking the ground powder, sieving the ground powder by a 600-mesh sieve, and taking undersize to obtain waste glass powder with the particle size of 600 meshes;
the epoxy resin is polyamide epichlorohydrin resin emulsion, and the solid content is 13%;
the curing agent used was tetraethylenepentamine with CAS number 112-57-2.
Preparation example 1
Modified basalt fiber production example 1
The modified basalt fiber in the preparation example is mainly prepared by the following steps:
1) taking a mixing barrel, placing a nitric acid solution in the barrel, soaking basalt fibers in the nitric acid solution for 20min, taking out the basalt fibers, washing the basalt fibers to be neutral by using clear water, and drying to obtain pretreated fibers;
2) taking a mixing barrel, placing a rare earth solution in the mixing barrel, placing the pretreated fiber prepared in the step 1) in the rare earth solution for soaking for 2.5 hours, taking out and drying to obtain the fiber; the rare earth solution is prepared from lanthanum chloride and water according to a mass ratio of 0.1: 100.
Modified basalt fiber production example 2
The preparation method of the modified basalt fiber in the preparation example is different from the preparation method of the modified basalt fiber in the preparation example 1 in that the rare earth solution used in the step 2) is prepared from lanthanum chloride and water according to the mass ratio of 0.9: 100, and the rest are the same as those in modified basalt preparation example 1.
Modified basalt fiber production example 3
The preparation method of the modified basalt fiber in the preparation example is different from the preparation method of the modified basalt fiber in the preparation example 1 in that the rare earth solution used in the step 2) is prepared from lanthanum chloride and water according to a mass ratio of 0.5: 100, and the rest are the same as those in modified basalt preparation example 1.
Modified basalt fiber preparation example 4
The modified basalt fiber in the preparation example is mainly prepared by the following steps:
1) taking a mixing barrel, placing a nitric acid solution in the barrel, soaking the basalt fiber in the nitric acid solution for 1.5 hours, taking out the basalt fiber, washing to be neutral, and drying to obtain a pretreated fiber;
2) taking a mixing barrel, placing a rare earth solution in the mixing barrel, placing the pretreated fiber prepared in the step 1) in the rare earth solution for soaking for 2.5 hours, carrying out ultrasonic oscillation on the rare earth solution and the pretreated fiber in the mixing barrel for 25min in the soaking process, taking out and drying to obtain the rare earth fiber; the rare earth solution is prepared from lanthanum chloride and water according to a mass ratio of 0.5: 100.
Example 1
The preparation method of the anti-crack concrete with low shrinkage rate in the embodiment comprises the following steps:
s1: taking a stirring barrel with a stirring paddle, putting 20kg of reinforcing fiber, 80kg of cement, 50kg of silica sand, 40kg of fly ash and 50kg of limestone into the stirring barrel together, and stirring and mixing through the stirring paddle to prepare a premix; the reinforcing fiber is prepared from modified basalt fiber and polyvinyl alcohol fiber according to a mass ratio of 3: 2, preparing a composition; the modified basalt fiber is prepared from modified basalt fiber preparation example 1;
s2: adding 100kg of water and 5kg of water reducing agent into the premix prepared in the step S1 together, and uniformly mixing by a stirring paddle to prepare a compound material;
s3: and (5) placing the compound mixture prepared in the step S2 into a mould, vibrating and molding, demoulding and maintaining to obtain the material.
Example 2
The preparation method of the anti-crack concrete with low shrinkage rate in the embodiment comprises the following steps:
s1: taking a stirring barrel with a stirring paddle, putting 40kg of reinforcing fiber, 120kg of cement, 90kg of silica sand, 80kg of fly ash and 80kg of limestone into the stirring barrel together, and stirring and mixing through the stirring paddle to prepare a premix; the reinforcing fiber is prepared from modified basalt fiber and polyvinyl alcohol fiber according to a mass ratio of 3: 2, preparing a composition; the modified basalt fiber is prepared from modified basalt fiber preparation example 1;
s2: adding 150kg of water and 8kg of water reducing agent into the premix prepared in the step S1 together, and uniformly mixing by a stirring paddle to prepare a compound material;
s3: and (5) placing the compound mixture prepared in the step (S2) into a mould, vibrating and molding, and demoulding and maintaining to obtain the material.
Example 3
The preparation method of the anti-crack concrete with low shrinkage rate in the embodiment comprises the following steps:
s1: taking a stirring barrel with a stirring paddle, putting 30kg of reinforcing fiber, 100kg of cement, 70kg of silica sand, 60kg of fly ash and 60kg of limestone into the stirring barrel together, and stirring and mixing through the stirring paddle to prepare a premix; the reinforcing fiber is prepared from modified basalt fiber and polyvinyl alcohol fiber according to a mass ratio of 3: 2, preparing a composition; the modified basalt fiber is prepared from modified basalt fiber preparation example 1;
s2: adding 120kg of water and 7kg of water reducing agent into the premix prepared in the step S1 together, and uniformly mixing by a stirring paddle to prepare a compound material;
s3: and (5) placing the compound mixture prepared in the step (S2) into a mould, vibrating and molding, and demoulding and maintaining to obtain the material.
Example 4
The preparation method of the anti-crack concrete with the low shrinkage rate in the embodiment is different from that in the embodiment 3 in that the reinforcing fiber used in the step S1 is prepared from modified basalt fiber and polyvinyl alcohol fiber according to a mass ratio of 5: 4, the rest being the same as in example 3.
Example 5
The preparation method of the anti-crack concrete with the low shrinkage rate in the embodiment is different from that in the embodiment 3 in that the reinforcing fiber used in the step S1 is prepared from modified basalt fiber and polyvinyl alcohol fiber according to a mass ratio of 4: 3, the rest being the same as in example 3.
Example 6
The preparation method of the anti-crack concrete with the low shrinkage rate in the embodiment is different from that in the embodiment 3 in that the reinforcing fiber used in the step S1 is prepared from modified basalt fiber and polypropylene fiber according to a mass ratio of 4: 3, the rest being the same as in example 3.
Example 7
The preparation method of the anti-crack concrete with the low shrinkage rate in the embodiment is different from that in the embodiment 3 in that the reinforcing fiber used in the step S1 is prepared from modified basalt fiber, polyvinyl alcohol fiber and polypropylene fiber according to a mass ratio of 4: 1.5: 1.5, the rest being the same as in example 3.
Example 8
The preparation method of the anti-crack concrete with low shrinkage rate in the embodiment comprises the following steps:
s1: taking a stirring barrel with a stirring paddle, putting 30kg of reinforcing fiber, 100kg of cement, 70kg of silica sand, 60kg of fly ash, 60kg of limestone and 20kg of waste glass powder into the stirring barrel together, and stirring and mixing through the stirring paddle to prepare a premix; the reinforcing fiber is prepared from modified basalt fiber, polyvinyl alcohol fiber and polypropylene fiber according to a mass ratio of 4: 1.5: 1.5; the modified basalt fiber is prepared from modified basalt fiber preparation example 1; the particle size of the used waste glass powder is 400 meshes;
s2: adding 120kg of water and 7kg of water reducing agent into the premix prepared in the step S1 together, and uniformly mixing by a stirring paddle to prepare a compound material;
s3: and (5) placing the compound mixture prepared in the step (S2) into a mould, vibrating and molding, and demoulding and maintaining to obtain the material.
Example 9
The preparation method of the anti-crack concrete with low shrinkage in this example is different from that of example 8 in that the mass of the waste glass powder added in step S1 is 30kg, and the rest is the same as that in example 8.
Example 10
The preparation method of the anti-crack concrete with low shrinkage in the embodiment is different from that of the embodiment 8 in that 25kg of waste glass powder is added in the step S1, and the rest is the same as that in the embodiment 8.
Example 11
The preparation method of the anti-crack concrete with low shrinkage in this example is different from that in example 10 in that the particle size of the waste glass powder added in step S1 is 800 mesh, and the rest is the same as that in example 10.
Example 12
The preparation method of the anti-crack concrete with low shrinkage in this example is different from that of example 10 in that the particle size of the waste glass powder added in step S1 is 600 mesh, and the rest is the same as that in example 10.
Example 13
The preparation method of the anti-crack concrete with low shrinkage rate in the embodiment comprises the following steps:
s1: taking a stirring barrel with a stirring paddle, putting 30kg of reinforcing fiber, 100kg of cement, 70kg of silica sand, 60kg of fly ash, 60kg of limestone and 25kg of waste glass powder into the stirring barrel together, and stirring and mixing through the stirring paddle to prepare a premix; the reinforcing fiber is prepared from modified basalt fiber, polyvinyl alcohol fiber and polypropylene fiber according to a mass ratio of 4: 1.5: 1.5; the modified basalt fiber is prepared from modified basalt fiber preparation example 1; the particle size of the used waste glass powder is 600 meshes;
s2: adding 120kg of water, 7kg of water reducing agent and 15kg of reinforcing resin into the premix prepared in the step S1 together, and uniformly mixing by a stirring paddle to prepare a compound material; the used reinforced resin is prepared from epoxy resin and a curing agent according to the mass ratio of 7: 1, preparing a composition; the epoxy resin is polyamide epoxy chloropropane resin emulsion, and the curing agent is tetraethylenepentamine;
s3: and (5) placing the compound mixture prepared in the step S2 into a mould, vibrating and molding, demoulding and maintaining to obtain the material.
Example 14
The preparation method of the anti-crack concrete with low shrinkage in the embodiment is different from that in the embodiment 13 in that the reinforced resin used in the step S2 is prepared from epoxy resin and a curing agent according to a mass ratio of 10: 2, the rest being the same as in example 13.
Example 15
The preparation method of the anti-crack concrete with low shrinkage in the embodiment is different from that in the embodiment 13 in that the reinforced resin used in the step S2 is prepared from epoxy resin and a curing agent according to a mass ratio of 8: 1.5, the rest being the same as in example 13.
Example 16
The preparation method of the anti-crack concrete with low shrinkage in this example is different from that in example 15 in that the modified basalt fiber used in step S2 is provided in modified basalt fiber preparation example 2, and the rest is the same as in example 15.
Example 17
The preparation method of the anti-crack concrete with low shrinkage in this example is different from that in example 15 in that the modified basalt fiber used in step S2 is provided in modified basalt fiber preparation example 3, and the rest is the same as in example 15.
Example 18
The preparation method of the anti-crack concrete with low shrinkage in this example is different from that in example 15 in that the modified basalt fiber used in step S2 is provided in modified basalt fiber preparation example 4, and the rest is the same as in example 15.
Comparative example
Comparative example 1
The preparation method of the low shrinkage anti-crack concrete in this comparative example is different from that of example 1 in that the basalt fiber used in step S1 is not subjected to the modification treatment, and the rest is the same as that of example 1.
Comparative example 2
The preparation method of the anti-crack concrete having a low shrinkage ratio in this comparative example is different from that of example 1 in that the preparation method of the modified basalt fiber used in step S1 includes the steps of: placing the basalt fiber in a rare earth solution to be soaked for 2.5h, taking out and drying to obtain the basalt fiber; the rest is the same as in example 1.
Detection method
Anti-crack concretes with low shrinkage rates were prepared as test samples according to the preparation methods of the anti-crack concretes with low shrinkage rates in examples 1 to 18 and comparative examples 1 to 2, respectively; the prepared test sample is tested for splitting tensile strength through GB/T50081-2002 'common concrete mechanical property test method', and data is recorded to obtain a table 1;
TABLE 1 results of the split tensile strength test of the low shrinkage anti-crack concrete test samples prepared in examples 1-18 and comparative examples 1-2
As can be seen by combining examples 3-7 with Table 1, the polyvinyl alcohol fibers have the characteristics of high strength, good affinity with other raw materials in concrete and the like; the polypropylene fiber has the characteristics of good elasticity, light weight and the like; meanwhile, after the basalt fiber is subjected to modification treatment, the surface roughness of the basalt fiber is improved, a rare earth film is formed by a rare earth solution and covers the surface of the basalt fiber, and the rare earth film can perform coordination chemical reaction with other organic active groups in concrete, so that the content of the organic active groups on the surface of the basalt fiber is increased, and the binding force between the modified basalt fiber and other raw materials is improved; the modified basalt fiber, the polyvinyl alcohol fiber and the polypropylene fiber are compounded together to form the reinforcing fiber, so that the cracking phenomenon of the anti-crack concrete with low shrinkage rate in the drying process is reduced, and the splitting tensile strength of the prepared anti-crack concrete with low shrinkage rate is improved.
In combination with examples 10 to 12 and table 1, it can be seen that when the particle size of the waste glass powder is too small, the effect of filling the pores on the surface of the gel material is not obvious, the compactness of the anti-crack concrete with low shrinkage rate is reduced, and the strength of the anti-crack concrete with low shrinkage rate is influenced; when the particle size of the waste glass powder is too large, the waste glass powder is easily aggregated in the anti-crack concrete with low shrinkage rate, the overall porosity of hydrate is not favorably reduced, and the anti-crack performance of the prepared anti-crack concrete with low shrinkage rate is influenced.
By combining the embodiment 1, the embodiment 16-17, the comparative example 1-2 and the table 1, it can be seen that by adjusting the concentration of the rare earth solution, when the concentration of the rare earth solution is lower, the number of active groups on the surface of the basalt fiber is insufficient, so that the binding force between the basalt fiber and other raw materials in the anti-crack concrete with low shrinkage rate is insufficient, and the anti-splitting performance of the modified basalt fiber to the anti-crack concrete with low shrinkage rate is insufficient; when the concentration of the rare earth solution is too high, the active groups formed on the surface of the basalt fiber before can be damaged by the too high rare earth solution, the rare earth film is easy to bulge or even crack under the action of tension, the bonding performance of the modified basalt fiber and other raw materials is influenced, and the splitting tensile strength of the anti-crack concrete with low shrinkage rate is influenced.
The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.
Claims (9)
1. An anti-crack concrete with low shrinkage rate is characterized in that: the composite material comprises the following raw materials in parts by weight: 100-150 parts of water, 80-120 parts of cement, 50-90 parts of silica sand, 40-80 parts of fly ash, 50-80 parts of limestone, 20-40 parts of reinforcing fiber and 5-8 parts of water reducing agent; the reinforcing fibers comprise modified basalt fibers; the preparation method of the modified basalt fiber comprises the following steps:
1): soaking basalt fibers in acid liquor, taking out, washing to be neutral, and drying to obtain pretreated fibers;
2): taking a rare earth solution, placing the pretreated fiber prepared in the step 1) in the rare earth solution, soaking for 2-3h, taking out and drying to obtain the fiber.
2. The low shrinkage, crack resistant concrete as claimed in claim 1, wherein: in the step 2), the rare earth solution is prepared from lanthanum chloride and water according to the mass ratio of (0.1-0.9): (95-105).
3. The low shrinkage, crack resistant concrete as claimed in claim 2, wherein: after the pretreated fiber in the step 2) is soaked in the rare earth solution, ultrasonic oscillation is carried out for 20-30min in the soaking process.
4. The low shrinkage, crack resistant concrete according to claim 1, wherein: the reinforcing fiber is prepared from modified basalt fiber, polyvinyl alcohol fiber and any one of polypropylene fiber according to the mass ratio (3-5): (2-4).
5. The low shrinkage, crack resistant concrete according to claim 1, wherein: the reinforced fiber is prepared from modified basalt fiber, polyvinyl alcohol fiber and polypropylene fiber according to the mass ratio (3-5): (1-2): (1-2).
6. The method for preparing an anti-crack concrete with low shrinkage rate according to claim 1, wherein the method comprises the following steps: the method comprises the following steps:
s1: mixing reinforced fiber, cement, silica sand, fly ash and limestone to prepare a premix;
s2: adding water and a water reducing agent into the premix prepared in the step S1 together, and uniformly mixing to prepare a compound material;
s3: and (5) placing the compound mixture prepared in the step (S2) into a mould, vibrating and molding, and demoulding and maintaining to obtain the material.
7. The method for preparing low shrinkage, anti-crack concrete according to claim 6, wherein: in step S1, 20-30 parts of waste glass powder is added before the reinforced fiber, the cement, the silica sand, the fly ash and the limestone are mixed.
8. The method for preparing low shrinkage, anti-crack concrete according to claim 7, wherein: the particle size of the added waste glass powder is 800-400 meshes.
9. The method for preparing low shrinkage, anti-crack concrete according to claim 6, wherein: in the step S1, after the water and the water reducing agent are added into the premix prepared in the step S1, 10-20 parts of reinforcing resin is added before mixing; the reinforced resin is prepared from epoxy resin and a curing agent according to the mass ratio (7-10): (1-2).
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