CN115536339A - High-strength high-ductility concrete and preparation method thereof - Google Patents

High-strength high-ductility concrete and preparation method thereof Download PDF

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Publication number
CN115536339A
CN115536339A CN202211303857.1A CN202211303857A CN115536339A CN 115536339 A CN115536339 A CN 115536339A CN 202211303857 A CN202211303857 A CN 202211303857A CN 115536339 A CN115536339 A CN 115536339A
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polyvinyl alcohol
fiber
preparing
parts
concrete
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俞建松
许广森
邹承忠
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Shenzhen Hengxing Building Material Co ltd
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Shenzhen Hengxing Building Material Co ltd
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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
    • 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
    • C04B16/00—Use of organic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of organic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
    • C04B16/04—Macromolecular compounds
    • C04B16/06—Macromolecular compounds fibrous
    • C04B16/0616—Macromolecular compounds fibrous from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B16/0641—Polyvinylalcohols; Polyvinylacetates
    • 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
    • C04B20/10—Coating or impregnating
    • C04B20/1018—Coating or impregnating with organic materials
    • C04B20/1029—Macromolecular compounds
    • C04B20/1037—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
    • D06M15/01—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with natural macromolecular compounds or derivatives thereof
    • D06M15/03—Polysaccharides or derivatives thereof
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
    • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
    • D06M15/37—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D06M15/564—Polyureas, polyurethanes or other polymers having ureide or urethane links; Precondensation products forming them
    • 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
    • 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
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M2101/00—Chemical constitution of the fibres, threads, yarns, fabrics or fibrous goods made from such materials, to be treated
    • D06M2101/16—Synthetic fibres, other than mineral fibres
    • D06M2101/18—Synthetic fibres consisting of macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D06M2101/24—Polymers or copolymers of alkenylalcohols or esters thereof; Polymers or copolymers of alkenylethers, acetals or ketones
    • 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 the field of concrete, and particularly discloses high-strength high-ductility concrete and a preparation method thereof. The high-strength high-ductility concrete comprises the following components in parts by weight: 190-225 parts of cement, 75-110 parts of blast furnace slag, 16-30 parts of silica fume, 105-120 parts of fine aggregate, 7-10 parts of modified polyvinyl alcohol fiber, 4.7-6 parts of steel fiber, 84-116 parts of water and 3-6 parts of water reducing agent; the raw materials of the modified polyvinyl alcohol fiber comprise, by weight, 1: (0.4-0.7) microporous polyvinyl alcohol fibers, aqueous polyurethane emulsion and carrageenan; the preparation method comprises the following steps: preparing microporous polyvinyl alcohol fibers, preparing modified polyvinyl alcohol fibers, preparing dry mixed materials, preparing wet mixed materials, premixing, mixing, pouring and maintaining. The method has the advantages of improving the strength and the ductility of the concrete and prolonging the service life of the concrete.

Description

High-strength high-ductility concrete and preparation method thereof
Technical Field
The application relates to the field of concrete, in particular to high-strength high-ductility concrete and a preparation method thereof.
Background
The common concrete is an artificial stone material prepared from cement, granular aggregate and water according to a certain proportion through uniform stirring, dense forming, curing and hardening. Because the constituent materials of concrete have the advantages of wide distribution, low price, wide applicability and the like, the concrete has become one of the most widely applied building materials in the civil engineering industry.
With the rapid development of civil engineering construction, higher requirements are placed on the strength of concrete, and particularly when the concrete is applied to high-rise structures and large-span structures, the requirement of the strength grade is usually over C60. However, high strength results in high brittleness, and the increase of brittleness of concrete results in the decrease of structural ductility, so that the concrete is more prone to crack under external action, thereby shortening the service life of the concrete.
Disclosure of Invention
In order to improve the strength and the ductility of the concrete and prolong the service life of the concrete, the application provides the high-strength high-ductility concrete and the preparation method.
The name provided by the application adopts the following technical scheme:
in a first aspect, the present application provides a high-strength and high-ductility concrete, which adopts the following technical scheme:
the high-strength high-ductility concrete comprises the following components in parts by weight: 190-225 parts of cement, 75-110 parts of blast furnace slag, 16-30 parts of silica fume, 105-120 parts of fine aggregate, 7-10 parts of modified polyvinyl alcohol fiber, 4.7-6 parts of steel fiber, 84-116 parts of water and 3-6 parts of water reducing agent;
the preparation method of the modified polyvinyl alcohol fiber comprises the following steps:
preparing microporous polyvinyl alcohol fibers: preparing polyvinyl alcohol resin into a polyvinyl alcohol solution with the concentration of 0.18-0.2, adding ammonium bicarbonate into the polyvinyl alcohol solution to obtain a spinning solution, wherein the weight ratio of polyvinyl alcohol to ammonium bicarbonate is 1: (0.0002 to 0.0008); spraying the spinning solution into a sodium sulfate solution with the concentration of 33-38% for coagulating bath treatment to obtain nascent fiber; adding the nascent fiber into a calcium hydroxide solution with the concentration of 0.6-0.15% for reaction to obtain secondary fiber; heating the secondary raw fiber for foaming, cleaning and drying to obtain microporous polyvinyl alcohol fiber;
preparing modified polyvinyl alcohol fiber: uniformly dispersing carrageenan in aqueous polyurethane emulsion, wherein the weight ratio of the aqueous polyurethane emulsion to the carrageenan is 1: (0.4-0.7), uniformly dispersing the microporous polyvinyl alcohol fibers in the mixed solution of the aqueous polyurethane emulsion and the carrageenan, uniformly stirring, standing, taking out the standing microporous polyvinyl alcohol fibers, and drying to obtain the modified polyvinyl alcohol fibers.
According to experimental results, the concrete prepared by adopting the technical scheme has good ductility and high strength.
The reason for analyzing the method by combining the experimental data is probably that the microporous polyvinyl alcohol fiber is modified by the carrageenan and the aqueous polyurethane emulsion, the surface of the microporous polyvinyl alcohol fiber is provided with a plurality of uniform micropores, the aqueous polyurethane emulsion is uniformly coated on the surface and in the micropores of the microporous polyvinyl alcohol fiber, the cohesiveness between the polyvinyl alcohol fiber and the concrete matrix is increased, and the carrageenan is bonded in the micropores on the surface of the microporous polyvinyl alcohol fiber by utilizing the viscosity of the aqueous polyurethane emulsion. In the process of concrete slurry hydration, the concrete hardens and contracts gradually, gaps appear gradually in the concrete matrix, and the carrageenan absorbs water and expands gradually, and the expanded carrageenan can be filled in the gaps in the concrete matrix, because the carrageenan and the micropores on the surfaces of the bonding and microporous polyvinyl alcohol fibers, and the cohesiveness of the concrete slurry enables the carrageenan to be bonded with the concrete matrix in the process of concrete slurry hardening, and the carrageenan serves as a bridge, so that the cohesiveness between the microporous polyvinyl alcohol fibers and the concrete matrix is increased.
When the concrete is subjected to external force and cracks are generated, the fibers generate a strong restraining effect at the cracks, the fibers play a bridging role and transmit stress at the cracks to a surrounding matrix, and stress concentration at the cracks is improved. When the adhesion between fibre and the concrete base member was less than external force, the fibre can be extracted from the concrete base member, leads to the crackle to enlarge, and the adhesion between modified polyvinyl alcohol fibre and the concrete base member in this application has obtained the reinforcing for modified polyvinyl alcohol fibre is difficult to extract from the concrete base member, thereby makes the difficult emergence fracture of concrete, has promoted the service life of concrete.
Optionally, the carrageenan is iota-carrageenan.
Through adopting above-mentioned technical scheme, iota type carrageenan has soft elasticity, receives the exogenic action when the concrete for fill the effect that can play certain buffering external force in the carrageenan in the concrete matrix, thereby alleviateed the concrete and received the destroyed phenomenon of external force.
Optionally, the viscosity of the aqueous polyurethane emulsion is 100-1000 mPa · s, and the solid content is 48-52%.
By adopting the technical scheme, the viscosity and the solid content of the waterborne polyurethane emulsion are moderate, so that the cohesiveness of the waterborne polyurethane emulsion is favorably ensured, and the operability is better in the process of preparing the modified polyvinyl alcohol fiber.
Optionally, the diameter of the modified polyvinyl alcohol fiber is 0.028-0.039 mm, and the length of the modified polyvinyl alcohol fiber is 11-13 mm; the diameter of the steel fiber is 0.3-0.4 mm, and the length is 17-26 mm.
By adopting the technical scheme, the modified polyvinyl alcohol fibers and the steel fibers are small in size, and can play a good role in bridging microcracks when the concrete is subjected to external force load, so that the crack development is controlled, the crack penetration is delayed, and the strength of the concrete is improved.
In a second aspect, the present application provides a preparation method for preparing the above high-strength and high-ductility concrete, which adopts the following technical scheme:
the preparation method of the high-strength high-ductility concrete comprises the following steps:
preparing a dry mixture: uniformly mixing cement, blast furnace slag, silica fume and fine aggregate to obtain a dry mixture;
preparing a wet mixed material: uniformly mixing a water reducing agent and water to obtain a wet mixed material;
pre-mixing: adding the wet mixture into the dry mixture, and stirring until the mixture is uniformly mixed to obtain a mixture;
mixing: adding the modified polyvinyl alcohol fiber into a blending species, and stirring until the modified polyvinyl alcohol fiber is uniformly dispersed in the blend to obtain a blended slurry;
and pouring and maintaining the mixed slurry to obtain the high-strength and high-ductility concrete.
By adopting the technical scheme, the concrete with high strength and high ductility can be prepared.
Optionally, in the step of preparing the microporous polyvinyl alcohol fiber, when the ammonium bicarbonate is added, the temperature of the polyvinyl alcohol solution is 40-60 ℃.
By adopting the technical scheme, the temperature of the polyvinyl alcohol solution is not enough, so that a large amount of gas is generated by decomposing the ammonium bicarbonate, the mixed solution of the polyvinyl alcohol solution and the ammonium bicarbonate is kept in a gel state, and the operability of the subsequent microporous polyvinyl alcohol fiber preparation process is facilitated.
Optionally, in the step of preparing the microporous polyvinyl alcohol fiber, the temperature of the sodium sulfate solution is 35 to 55 ℃ when the sodium sulfate solution is used for coagulation bath treatment, and the running speed of the colloid sprayed by the spinning solution in the sodium sulfate solution is 5 to 8m/s.
By adopting the technical scheme, the processing parameters are favorable for the secondary fibers to have better dimensional stability.
Optionally, in the step of preparing the microporous polyvinyl alcohol fiber, the temperature of the secondary fiber is 180-250 ℃ when the secondary fiber is heated for foaming.
By adopting the technical scheme, the temperature range is favorable for the decomposition of the ammonium bicarbonate which is not completely reacted to generate gas to overflow from the secondary fibers, so that more micropores can be left on the surface of the primary finished product.
In summary, the present application has the following beneficial effects:
1. because the microporous polyvinyl alcohol fiber is modified by the aqueous polyurethane emulsion and the carrageenan, the carrageenan has a bridging effect between the modified polyvinyl alcohol fiber and the concrete matrix, the cohesiveness between the modified polyvinyl alcohol fiber and the concrete matrix is enhanced, and the effect of enhancing and toughening the concrete is obtained;
2. according to the preparation method, the prepared concrete not only has high strength, but also has excellent ductility.
Detailed Description
The present application is described in further detail below.
Introduction of the starting materials the following starting materials were used for examples 1 to 3 and comparative examples 1 to 4:
TABLE 1 partial material introduction for high-strength and high-ductility concrete
Raw materials Delivery and model introduction
Portland cement The model is as follows: p, II 52.5
Blast furnace slag The grain diameter is 5-100 mu m
Silica fume The grain diameter is 1-10 mu m
Fine aggregate Refined quartz sand with 70-150 meshes of fineness
Steel fiber The diameter is 0.3-0.4 mm, the length is 17-26 mm
Water (W) Tap water
High-efficiency polycarboxylic acid water reducing agent The water reducing rate is more than or equal to 25 percent, the bleeding rate ratio is less than or equal to 60 percent, and the pH value is 5 to 8
Aqueous polyurethane emulsion The viscosity of 600-1000 mPas is more than or equal to 49 percent, and the pH value is 6-9
Carrageenan Brand name: source leaf, brand: s30560
Polyvinyl alcohol resin The model is as follows: 2488 and has fineness modulus of 80 meshes and purity of 96% or more
Examples
Example 1
The high-strength high-ductility concrete is prepared from the following raw materials: 190kg of Portland cement, 110kg of blast furnace slag, 16kg of silica fume, 120kg of quartz sand, 7kg of modified polyvinyl alcohol fiber, 6kg of steel fiber, 84kg of water and 6kg of water reducing agent; the modified polyvinyl alcohol fiber is prepared from 1.7kg of microporous polyvinyl alcohol fiber, 3.8kg of aqueous polyurethane emulsion and 1.5kg of carrageenan.
The preparation method of the high-strength high-ductility concrete comprises the following steps:
preparing microporous polyvinyl alcohol fibers: adding polyvinyl alcohol resin and water into a dissolving kettle according to the proportion of 1:8, heating to 105 ℃, stirring at the speed of 45rmp until the polyvinyl alcohol resin is completely dissolved in the water to obtain polyvinyl alcohol solution; when the spinning solution is cooled to 50 ℃, adding ammonium bicarbonate into a dissolving kettle, wherein the weight ratio of the ammonium bicarbonate to the polyvinyl alcohol resin is 0.0006; dissolving sodium sulfate in water to prepare a sodium sulfate solution with the concentration of 35%, adding a spinning stock solution into a spinning machine for spraying, putting sprayed colloid into the sodium sulfate solution for coagulating bath treatment, wherein the treatment temperature is 45 ℃, and the running speed of the colloid is 6m/s, so as to obtain nascent fiber; dissolving sodium hydroxide in water to prepare a sodium hydroxide solution with the concentration of 0.01%, and adding the nascent fiber into the sodium hydroxide solution for reaction to obtain a secondary fiber; introducing the secondary fibers into a drying tunnel, keeping the temperature in the drying tunnel at 220 ℃, foaming, and simultaneously drawing the secondary fibers forwards at a speed of 30m/min to obtain a primary finished product with the diameter of 0.035mm and the length of 12 mm; cleaning and drying the primary finished product to obtain microporous polyvinyl alcohol fibers;
preparing modified polyvinyl alcohol fiber: uniformly dispersing carrageenan in aqueous polyurethane emulsion, uniformly dispersing microporous polyvinyl alcohol fibers in the aqueous polyurethane emulsion, stirring at the speed of 15rpm for 20min, standing for 20min until the microporous polyvinyl alcohol fibers are completely soaked, taking out the modified microporous polyvinyl alcohol fibers, and drying to obtain modified polyvinyl alcohol fibers;
preparing a dry mixture: adding cement, blast furnace slag, silica fume and fine aggregate into a stirrer, and stirring for 2min to obtain a dry mixture;
preparing a wet mixed material: mixing and stirring a water reducing agent and water for 2min to obtain a wet mixed material;
pre-mixing: adding the wet mixture into the dry mixture, and stirring for 5min to obtain a mixture;
blending: adding the modified polyvinyl alcohol fiber into a blending substance, and stirring for 3min to uniformly disperse the modified polyvinyl alcohol fiber in the blend to obtain a blended slurry;
pouring and maintaining: pouring the mixed slurry into a mold for molding, and covering a layer of polyethylene film to prevent water loss; and (3) curing for 24 hours at room temperature, then removing the mold, and placing the mold in a standard curing room (the temperature is 20 ℃, and the relative humidity is more than 95%) for curing for 7 days to obtain the high-strength and high-ductility concrete.
Example 2
A high-strength high-ductility concrete is prepared from the following raw materials: 225kg of Portland cement, 75kg of blast furnace slag, 30kg of silica fume, 105kg of quartz sand, 10kg of modified polyvinyl alcohol fiber, 4.7kg of steel fiber, 116kg of water and 3kg of water reducing agent; the modified polyvinyl alcohol fiber is prepared from 2.1kg of microporous polyvinyl alcohol fiber, 4.6kg of aqueous polyurethane emulsion and 3.3kg of carrageenan.
The preparation method of the high-strength high-ductility concrete comprises the following steps:
preparing microporous polyvinyl alcohol fibers: adding polyvinyl alcohol resin and water into a dissolving kettle according to the proportion of 1:8, heating to 105 ℃, stirring at the speed of 45rmp until the polyvinyl alcohol resin is completely dissolved in the water to obtain polyvinyl alcohol solution; when the spinning solution is cooled to 50 ℃, adding ammonium bicarbonate into a dissolving kettle, wherein the weight ratio of the ammonium bicarbonate to the polyvinyl alcohol resin is 0.0006; dissolving sodium sulfate in water to prepare a sodium sulfate solution with the concentration of 35%, adding a spinning stock solution into a spinning machine for spraying, putting sprayed colloid into the sodium sulfate solution for coagulating bath treatment, wherein the treatment temperature is 45 ℃, and the running speed of the colloid is 6m/s, so as to obtain nascent fiber; dissolving sodium hydroxide in water to prepare a sodium hydroxide solution with the concentration of 0.01%, and adding the nascent fiber into the sodium hydroxide solution for reaction to obtain a secondary fiber; introducing the secondary fibers into a drying tunnel, keeping the temperature in the drying tunnel at 220 ℃, foaming, and simultaneously drawing the secondary fibers forwards at a speed of 30m/min to obtain a primary finished product with the diameter of 0.035mm and the length of 12 mm; cleaning and drying the primary finished product to obtain microporous polyvinyl alcohol fibers;
preparing modified polyvinyl alcohol fiber: uniformly dispersing carrageenan in aqueous polyurethane emulsion, uniformly dispersing microporous polyvinyl alcohol fibers in the aqueous polyurethane emulsion, stirring at the speed of 15rpm for 20min, standing for 20min until the microporous polyvinyl alcohol fibers are completely soaked, taking out the modified microporous polyvinyl alcohol fibers, and drying to obtain modified polyvinyl alcohol fibers;
preparing a dry mixture: adding cement, blast furnace slag, silica fume and fine aggregate into a stirrer, and stirring for 2min to obtain a dry mixture;
preparing a wet mixed material: mixing and stirring a water reducing agent and water for 2min to obtain a wet mixed material;
pre-mixing: adding the wet mixture into the dry mixture, and stirring for 5min to obtain a mixture;
blending: adding the modified polyvinyl alcohol fibers into a blending species, and stirring for 3min to uniformly disperse the modified polyvinyl alcohol fibers in the blend to obtain a blended slurry;
pouring and maintaining: pouring the mixed slurry into a mold for molding, and covering a layer of polyethylene film to prevent water loss; and (3) curing for 24 hours at room temperature, then removing the mold, and placing the mold in a standard curing room (the temperature is 20 ℃, and the relative humidity is more than 95%) for curing for 7 days to obtain the high-strength and high-ductility concrete.
Example 3
The high-strength high-ductility concrete is prepared from the following raw materials: 207kg of Portland cement, 92kg of blast furnace slag, 23kg of silica fume, 112kg of quartz sand, 8kg of modified polyvinyl alcohol fiber, 5kg of steel fiber, 100kg of water and 4kg of water reducing agent; the modified polyvinyl alcohol fiber is prepared from 1.8kg of microporous polyvinyl alcohol fiber, 4.1kg of aqueous polyurethane emulsion and 2.1kg of carrageenan.
The preparation method of the high-strength high-ductility concrete comprises the following steps:
preparing microporous polyvinyl alcohol fibers: adding polyvinyl alcohol resin and water into a dissolving kettle according to the proportion of 1:8, heating to 105 ℃, stirring at the speed of 45rmp until the polyvinyl alcohol resin is completely dissolved in the water, and obtaining the polyvinyl alcohol solution; when the spinning solution is cooled to 50 ℃, adding ammonium bicarbonate into the dissolving kettle, wherein the weight ratio of the ammonium bicarbonate to the polyvinyl alcohol resin is 0.0006; dissolving sodium sulfate in water to prepare a sodium sulfate solution with the concentration of 35%, adding a spinning stock solution into a spinning machine for spraying, and allowing sprayed colloid to enter the sodium sulfate solution for coagulation bath treatment at the treatment temperature of 45 ℃ and the running speed of the colloid of 6m/s to obtain nascent fiber; dissolving sodium hydroxide in water to prepare a sodium hydroxide solution with the concentration of 0.01%, and adding the nascent fiber into the sodium hydroxide solution for reaction to obtain a secondary fiber; introducing the secondary fibers into a drying tunnel, keeping the temperature in the drying tunnel at 220 ℃, foaming, and simultaneously drawing the secondary fibers forwards at a speed of 30m/min to obtain a primary finished product with the diameter of 0.035mm and the length of 12 mm; cleaning and drying the primary finished product to obtain microporous polyvinyl alcohol fibers;
preparing modified polyvinyl alcohol fiber: uniformly dispersing carrageenan in aqueous polyurethane emulsion, uniformly dispersing microporous polyvinyl alcohol fibers in the aqueous polyurethane emulsion, stirring at the speed of 15rpm for 20min, standing for 20min until the microporous polyvinyl alcohol fibers are completely soaked, taking out the modified microporous polyvinyl alcohol fibers, and drying to obtain modified polyvinyl alcohol fibers;
preparing a dry mixture: adding cement, blast furnace slag, silica fume and fine aggregate into a stirrer, and stirring for 2min to obtain a dry mixture;
preparing a wet mixed material: mixing and stirring a water reducing agent and water for 2min to obtain a wet mixed material;
pre-mixing: adding the wet mixture into the dry mixture, and stirring for 5min to obtain a mixture;
blending: adding the modified polyvinyl alcohol fibers into a blending species, and stirring for 3min to uniformly disperse the modified polyvinyl alcohol fibers in the blend to obtain a blended slurry;
pouring and maintaining: pouring the mixed slurry into a mold for molding, and covering a layer of polyethylene film to prevent water loss; and (3) curing for 24 hours at room temperature, then removing the mold, and placing the mold in a standard curing room (the temperature is 20 ℃, and the relative humidity is more than 95%) for curing for 7 days to obtain the high-strength and high-ductility concrete.
Comparative example
Comparative example 1
Comparative example 1 differs from example 3 in that: modified polyvinyl alcohol fibers are not adopted in the preparation raw materials, namely unmodified polyvinyl alcohol fibers with the same weight are adopted for replacement.
Comparative example 2
Comparative example 2 differs from example 3 in that: the raw material of the modified polyvinyl alcohol fiber does not adopt microporous polyvinyl alcohol fiber, namely, unmodified polyvinyl alcohol fiber with the same weight is adopted for replacement.
Comparative example 3
Comparative example 3 differs from example 3 in that: the raw materials of the modified polyvinyl alcohol fiber are not added with the aqueous polyurethane emulsion, and are replaced by water with the same weight.
Comparative example 4
Comparative example 4 differs from example 3 in that: the raw materials of the modified polyvinyl alcohol fiber are not added with carrageenan, namely, the raw materials are replaced by the aqueous polyurethane emulsion with the same weight.
Performance detection
The high-strength and high-ductility concrete samples prepared in examples 1 to 3 and comparative examples 1 to 4 were subjected to the tests for compressive strength and ductility.
Wherein, the ductility is characterized by flexural strength, tensile strength and ultimate elongation. According to JC/T2461-2018, namely a mechanical property test method for a high-ductility fiber reinforced cement-based composite material, an MTS universal tester is adopted to test the compressive strength, the flexural strength and the tensile strength.
Table 2 contains the results of the performance test of the high-strength and high-ductility samples prepared in examples 1 to 3 and comparative examples 1 to 4
Figure BDA0003905856320000071
Figure BDA0003905856320000081
According to the experimental data reported in table 2, compared with comparative example 1, the high-strength and high-ductility concrete prepared in example 3 of the present application has a greater improvement in compressive strength, flexural strength, tensile strength and ultimate elongation, which indicates that the modified polyvinyl alcohol fiber added in the present application can provide beneficial help in improving the strength and ductility of the concrete.
The reason for analyzing the concrete structure probably lies in that the carrageenan is bonded in the micropores on the surfaces of the microporous polyvinyl alcohol fibers by utilizing the viscosity of the aqueous polyurethane emulsion, the carrageenan is bonded with the concrete matrix in the hardening process of the concrete slurry by the cohesiveness of the concrete slurry, and the carrageenan is used as a bridge to increase the cohesiveness between the microporous polyvinyl alcohol fibers and the concrete matrix, so that when the concrete is subjected to external force load, the modified polyvinyl alcohol fibers are not easy to be pulled out from the concrete matrix and separated from the concrete matrix, the modified polyvinyl alcohol fibers continue to generate a bridging effect, and the concrete is not easy to break.
As can be seen from comparison between comparative examples 2 to 4 and example 3, when the common polyvinyl alcohol fiber or the lack of the aqueous polyurethane emulsion or the carrageenan is adopted in the raw material of the modified polyvinyl alcohol fiber, no beneficial effect is brought to the strength and ductility of the concrete, which indicates that the microporous polyvinyl alcohol fiber, the aqueous polyurethane emulsion and the carrageenan play a role in improving the strength and ductility of the concrete.
In addition, at the in-process of concrete slurry hydration, the concrete hardens the shrink gradually, and the gap appears gradually in the concrete base, and the carrageenan progressively takes place the inflation that absorbs water simultaneously, and the carrageenan after the inflation can be filled in the gap in the concrete base, and when the concrete received the exogenic action, make the carrageenan of filling in the concrete base can play the effect of certain buffering exogenic action to make the concrete be difficult for receiving the exogenic damage.
The above-mentioned embodiments are merely illustrative and not restrictive, and those skilled in the art who review this disclosure may make modifications to the present disclosure as needed without any inventive contribution, but all such modifications are intended to be included within the scope of the present disclosure.

Claims (8)

1. The high-strength high-ductility concrete is characterized by comprising the following components in parts by weight: 190-225 parts of cement, 75-110 parts of blast furnace slag, 16-30 parts of silica fume, 105-120 parts of fine aggregate, 7-10 parts of modified polyvinyl alcohol fiber, 4.7-6 parts of steel fiber, 84-116 parts of water and 3-6 parts of water reducing agent;
the preparation method of the modified polyvinyl alcohol fiber comprises the following steps:
preparing microporous polyvinyl alcohol fibers: preparing polyvinyl alcohol resin into a polyvinyl alcohol solution with the concentration of 0.18-0.2, adding ammonium bicarbonate into the polyvinyl alcohol solution to obtain a spinning solution, wherein the weight ratio of polyvinyl alcohol to ammonium bicarbonate is 1: (0.0002 to 0.0008); spraying the spinning solution into a sodium sulfate solution with the concentration of 33-38% for coagulating bath treatment to obtain nascent fiber; adding the nascent fiber into a calcium hydroxide solution with the concentration of 0.6-0.15% for reaction to obtain a secondary fiber; heating the secondary raw fiber for foaming, cleaning and drying to obtain microporous polyvinyl alcohol fiber;
preparing modified polyvinyl alcohol fiber: uniformly dispersing carrageenan in aqueous polyurethane emulsion, wherein the weight ratio of the aqueous polyurethane emulsion to the carrageenan is 1: (0.4-0.7), uniformly dispersing the microporous polyvinyl alcohol fibers in the mixed solution of the aqueous polyurethane emulsion and the carrageenan, uniformly stirring, standing, taking out the standing microporous polyvinyl alcohol fibers, and drying to obtain the modified polyvinyl alcohol fibers.
2. The high-strength high-ductility concrete according to claim 1, characterized in that: the carrageenan adopts iota type carrageenan.
3. The high-strength high-ductility concrete according to claim 1, characterized in that: the viscosity of the aqueous polyurethane emulsion is 100-1000 mPa.s, and the solid content is 48-52%.
4. The high strength high ductility concrete according to claim 1, wherein: the diameter of the modified polyvinyl alcohol fiber is 0.028-0.039 mm, and the length of the modified polyvinyl alcohol fiber is 11-13 mm; the diameter of the steel fiber is 0.3-0.4 mm, and the length is 17-26 mm.
5. A method for preparing a high-strength high-ductility concrete according to any one of claims 1 to 4, characterized in that: the method comprises the following steps:
preparing a dry mixture: uniformly mixing cement, blast furnace slag, silica fume and fine aggregate to obtain a dry mixture;
preparing a wet mixed material: uniformly mixing a water reducing agent and water to obtain a wet mixed material;
pre-mixing: adding the wet mixture into the dry mixture, and stirring until the mixture is uniformly mixed to obtain a mixture;
mixing: and adding the modified polyvinyl alcohol fibers into the blending species, and stirring until the modified polyvinyl alcohol fibers are uniformly dispersed in the blending species, thereby obtaining the high-strength high-ductility concrete.
6. The method for preparing high-strength high-ductility concrete according to claim 1, wherein: in the step of preparing the microporous polyvinyl alcohol fiber, when ammonium bicarbonate is added, the temperature of the polyvinyl alcohol solution is 40-60 ℃.
7. The method for preparing high-strength high-ductility concrete according to claim 1, wherein: in the step of preparing the microporous polyvinyl alcohol fiber, the temperature of the sodium sulfate solution is 35-55 ℃ when the sodium sulfate solution is used for coagulating bath treatment, and the running speed of the colloid sprayed by the spinning solution in the sodium sulfate solution is 5-8 m/s.
8. The method for preparing high-strength high-ductility concrete according to claim 1, wherein: in the step of preparing the microporous polyvinyl alcohol fiber, the temperature of the secondary fiber is 180-250 ℃ when the secondary fiber is heated for foaming.
CN202211303857.1A 2022-10-24 2022-10-24 High-strength high-ductility concrete and preparation method thereof Pending CN115536339A (en)

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US20180162777A1 (en) * 2016-12-12 2018-06-14 United States Gypsum Company Self-desiccating, dimensionally-stable hydraulic cement compositions with enhanced workability
CN109851293A (en) * 2018-12-30 2019-06-07 华新新型建材(武汉)有限公司 A kind of superfluidity, high tenacity cement-based material and its preparation and construction method
CN110981344A (en) * 2019-12-16 2020-04-10 深圳市龙岗大工业区混凝土有限公司 Environment-friendly recycled concrete and preparation process thereof
CN111334884A (en) * 2020-03-23 2020-06-26 浙江红雨医药用品有限公司 Preparation method of microporous polyvinyl alcohol fibers
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102372459A (en) * 2010-08-24 2012-03-14 上海台界化工有限公司 Method for enhancing workability of concrete
US9624131B1 (en) * 2015-10-22 2017-04-18 United States Gypsum Company Freeze-thaw durable geopolymer compositions and methods for making same
US20180162777A1 (en) * 2016-12-12 2018-06-14 United States Gypsum Company Self-desiccating, dimensionally-stable hydraulic cement compositions with enhanced workability
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Application publication date: 20221230