CN111517728B - Composition, prefabricated part and preparation method thereof - Google Patents

Composition, prefabricated part and preparation method thereof Download PDF

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Publication number
CN111517728B
CN111517728B CN202010473500.2A CN202010473500A CN111517728B CN 111517728 B CN111517728 B CN 111517728B CN 202010473500 A CN202010473500 A CN 202010473500A CN 111517728 B CN111517728 B CN 111517728B
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concrete
polymer
parts
emulsion
redispersible
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CN111517728A (en
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孔祥明
张朝阳
王健
尹健昊
喻建伟
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Tsinghua University
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Tsinghua University
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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
    • 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
    • B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
    • B28B11/24—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
    • B28B11/245—Curing concrete articles
    • 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
    • B28B7/00—Moulds; Cores; Mandrels
    • B28B7/22—Moulds for making units for prefabricated buildings, i.e. units each comprising an important section of at least two limiting planes of a room or space, e.g. cells; Moulds for making prefabricated stair units
    • 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
    • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
    • C04B24/24—Macromolecular compounds
    • C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B24/2641—Polyacrylates; Polymethacrylates
    • 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
    • C04B28/06—Aluminous 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
    • 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
    • C04B28/08—Slag 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
    • 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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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Structural Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

The invention relates to a composition, a prefabricated part and application thereof. The composition comprises a gelled material, a polymer emulsion and/or a redispersible polymer rubber powder, fine aggregate and optionally coarse aggregate, wherein the glass transition temperature of the polymer emulsion and/or the redispersible polymer rubber powder is more than 20 ℃. The polymer emulsion with high glass transition temperature is applied to a concrete (mortar) prefabricated part, and the concrete prefabricated part with excellent mechanical property, impermeability and durability is prepared in a steam curing mode. The method not only exerts the advantage that the high glass transition temperature polymer has little influence on the compressive strength of the concrete (mortar), but also can greatly improve the breaking strength, the impermeability and the durability of the concrete (mortar) through polymer film formation, and simultaneously overcomes the defects of rough aperture and large brittleness commonly existing in the existing steam-cured member.

Description

Composition, prefabricated part and preparation method thereof
Technical Field
The invention belongs to the technical field of building materials, and particularly relates to a composition, a prefabricated part and a preparation method thereof.
Background
Cement concrete is one of the most widely used building materials in the world today. In recent years, with the rapid development of the infrastructure of high-speed railways, fabricated houses, subway tunnels, water supply and drainage pipelines, bridges and the like in China, the demand of concrete prefabricated parts is rapidly increased. Compared with cast-in-place concrete, the precast concrete member has unique advantages, such as industrial production, easy quality guarantee, advanced completion of most shrinkage, contribution to civilized construction and environmental protection, shortening of construction period and the like.
In order to shorten the concrete demoulding time and accelerate the turnover rate of the template, a steam curing process is generally adopted in the production process of the concrete prefabricated part. The steam curing improves the early hydration hardening speed of the concrete and simultaneously has certain negative effects on the concrete, such as large brittleness, easy cracking, low later strength, poor durability and the like. Steam curing may have adverse effects on cement hydration products and pore structures in concrete, Patel research shows that the generation of the hydration products, particularly ettringite, is accelerated by the increase of temperature, a coarser pore structure is caused, and even reticular cracks appear in the service process of the concrete cured at the temperature of 85 ℃. Kjellsen finds that the porosity of the concrete cured at 50 ℃ after long-term service is higher than that of the concrete cured at 20 ℃. The Barbara study found that high temperature curing resulted in an uneven distribution of hydration products, while at low temperatures the hydration products had sufficient time to diffuse and thus be more evenly distributed in the cement matrix. Li Xiaoling researches show that whether the concrete is ordinary concrete or concrete mixed with mineral admixtures, the early compressive strength and the tensile strength of the concrete are increased along with the increase of the curing temperature, and the change rule of the long-term strength and the curing temperature is just opposite to that of the early strength.
Polymer emulsions and redispersible powders are often incorporated into concrete to improve their cohesive strength, flexural strength, toughness, impermeability, and durability due to their good toughness and bonding properties. However, although the existing polymer modified concrete has excellent flexural strength and impermeability, the compressive strength, especially the early compressive strength, of the existing polymer modified concrete is usually much lower than that of the common concrete. When the mixing amount reaches 10 percent of the cement using amount, the polymer emulsion can reduce the strength of mortar or concrete by more than half even, so that the prior polymer modified mortar or concrete is not generally used as a structural material.
Disclosure of Invention
In order to solve the problems of the prior art, the first aspect of the present invention provides a composition, which will include a high glass transition temperature polymer emulsion, to exert the advantage of low impact of the high glass transition temperature polymer on the compressive strength of concrete (mortar), and to greatly improve the flexural strength, impermeability and durability of concrete (mortar) through polymer film formation.
A second aspect of the invention provides a prefabricated element.
In a third aspect of the present invention, there is provided a method for producing the above prefabricated part.
A fourth aspect of the invention provides the use of the above composition and prefabricated parts.
According to a first aspect, the present invention provides a composition comprising a cementitious material, a polymer emulsion and/or a redispersible polymer gum powder having a glass transition temperature of greater than 20 ℃, fine aggregate and optionally coarse aggregate.
According to some embodiments of the invention, the composition is a concrete composition comprising a cementitious material, a polymer emulsion and/or a redispersible polymer gum powder, a fine aggregate and a coarse aggregate.
According to some embodiments of the invention, the composition is a mortar composition comprising a cementitious material, a polymer emulsion and/or a redispersible polymer powder and a fine aggregate.
In the research of concrete or mortar, the inventor finds that in order to enable the polymer to form a continuous polymer film in the concrete to achieve the effects of bridging cracks and improving the breaking strength and impermeability, the polymer emulsion used at present has the common characteristic that the glass transition temperature of the polymer phase is lower than the ambient temperature, and in the polymer emulsion used for polymer modified mortar and concrete in the market, the glass transition temperature (T) of the polymer isg) Mostly between-10 ℃ and 20 ℃. These TgThe polymer emulsion with the temperature lower than the application temperature of mortar and concrete gradually consumes free water in the hydration process of cement, nano particles in the polymer emulsion are gradually densely stacked, deformed and fused into a film, and the impermeability of the mortar and the concrete is greatly improved.
At the same time, the polymer is used to modify the mortar and the mixtureThe improvement of the flexural tensile strength, the bonding strength and the toughness of the concrete is related to the film formation of the polymer. Glass transition temperature (T)g) The polymer emulsion above 25 ℃ can not form a film at normal temperature, so the improvement effect on the flexural strength and the impermeability of mortar and concrete is not obvious, and the polymer emulsion is mainly used as an interface agent between the mortar and the concrete and an important component of other decorative materials. But due to TgThe lower the elastic modulus of the polymer itself, the stronger the retarding effect of the polymer on cement hydration, the better the film-forming properties. Therefore, although the existing polymer modified concrete has excellent flexural strength and impermeability, the compressive strength, especially the early compressive strength, is usually much lower than that of common concrete. When the mixing amount reaches 10 percent of the cement dosage, part of TgLower polymer emulsions can even reduce the strength of mortar or concrete by more than half, and therefore polymer modified mortars or concretes are not generally used as structural materials.
The invention creatively introduces high T into concrete or mortargFound to have a high TgThe polymer emulsion has negative influence on the compressive strength of mortar or concrete when being mixed into the mortar or concrete, which is far less than the low T commonly used at presentgThe polymer emulsion of (1). This is due to TgThe higher the mechanical strength of the polymer film. Meanwhile, the curing temperature of mortar or concrete is increased, and high T can be promotedgThe polymer emulsion forms a film, thereby greatly improving the breaking strength and the impermeability of the polymer modified mortar at normal temperature. Meanwhile, the compressive strength of the mortar and the concrete is not much different from that of common mortar and concrete, and is even slightly improved, so that the application range of the polymer modified mortar or concrete is expanded.
According to some embodiments of the invention, the glass transition temperature of the polymer emulsion and/or the redispersible polymer gum powder is 25 to 90 ℃, such as 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 52 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃ and the like.
According to some embodiments of the invention, the glass transition temperature of the polymer emulsion and/or the redispersible polymer gum powder is in the range of 30 to 70 ℃, such as 35 ℃, 40 ℃, 45 ℃, 50 ℃, 52 ℃, 55 ℃, 60 ℃, 70 ℃ and the like.
By controlling the glass transition temperature within the range, the invention can obtain the prefabricated part with better mechanical property and does not require too high steam curing temperature.
According to some embodiments of the invention, the polymer emulsion is selected from one or more of aqueous polymer emulsions.
According to some embodiments of the invention, the polymer emulsion is selected from one or more of a styrene-acrylic emulsion, a styrene-butadiene emulsion, an ethylene-vinyl acetate copolymer emulsion, a styrene emulsion, and an acrylate emulsion.
According to some embodiments of the present invention, the polymer emulsion includes, but is not limited to, styrene-acrylic emulsion, styrene-butadiene emulsion, ethylene-vinyl acetate copolymer emulsion, styrene emulsion, acrylic emulsion, and emulsion obtained by modifying or mixing based on these emulsions.
According to some embodiments of the invention, the polymer emulsion has a solids content of 20 to 70%, for example 40%.
According to some embodiments of the invention, the redispersible polymer glue powder is selected from one or more of redispersible aqueous polymer glue powders.
According to some embodiments of the invention, the redispersible polymer rubber powder is selected from one or more of redispersible styrene-acrylic rubber powder, redispersible styrene-butadiene rubber powder, redispersible ethylene-vinyl acetate copolymer rubber powder, redispersible styrene rubber powder, and redispersible acrylic acid ester rubber powder.
According to some embodiments of the present invention, the redispersible polymer rubber powder includes, but is not limited to, redispersible styrene-acrylic rubber powder, redispersible styrene-butadiene rubber powder, redispersible ethylene-vinyl acetate copolymer rubber powder, redispersible styrene rubber powder, and redispersible acrylic rubber powder obtained by modifying or mixing redispersible polymer rubber powder based on these redispersible polymer rubber powder.
According to some embodiments of the present invention, the polymer emulsion and/or the redispersible polymer gum powder preferably satisfy the following characteristics: 1) can be uniformly mixed with the cement-based material; 2) the stability in high salt solution can be kept good; 3) the glass transition temperature is higher than the practical temperature and lower than the steam curing temperature.
According to some embodiments of the invention, the composition further comprises one or more of water, a water reducing agent, and a defoamer.
According to some embodiments of the present invention, in order to further improve the performance of the composition, the composition further comprises other common chemical additives, such as an early strength agent or an antifreeze agent.
According to some embodiments of the invention, the mass content of the solid phase in the polymer emulsion and/or the mass content of the redispersible polymer glue powder is 0.5-30% by weight, based on the total weight of the cement, such as 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% and any value therebetween.
According to some embodiments of the invention, the mass content of the solid phase in the polymer emulsion and/or the mass content of the redispersible polymer powder is between 1 and 20% by weight, based on the total weight of the cementitious material.
According to some embodiments of the invention, the mass content of solid phase in the polymer emulsion and/or the mass content of the redispersible polymer powder is between 2 and 10% by weight, based on the total weight of the cementitious material.
According to some embodiments of the invention, the mass content of the solid phase in the polymer emulsion and/or the mass content of the redispersible polymer glue powder is 0.5-10% by weight of the total weight of the composition, such as 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10% and any value in between.
According to some embodiments of the invention, the mass content of the solid phase in the polymer emulsion and/or the mass content of the redispersible polymer glue powder is between 0.5 and 5% by weight, based on the total weight of the composition.
According to some embodiments of the invention, the mass content of the gelling material is between 15 and 40%, such as 15%, 20%, 25%, 30%, 35%, 40% and any value in between, based on the total weight of the composition.
According to some embodiments of the invention, the gelling material is present in an amount of 10 to 35% by weight, based on the total weight of the composition.
According to some embodiments of the invention, the coarse aggregate is present in an amount of 0 to 60% by mass, for example 0%, 10%, 20%, 30%, 40%, 50%, 60% and any value therebetween, based on the total weight of the composition.
According to some embodiments of the invention, the coarse aggregate is present in the mortar composition in an amount of 0 by mass based on the total weight of the composition.
According to some embodiments of the invention, the coarse aggregate is present in the concrete composition in an amount of 30 to 50% by mass, based on the total weight of the composition.
According to some embodiments of the invention, the fine aggregate is present in an amount of 30-70% by mass, such as 30%, 40%, 50%, 60%, 70% and any value therebetween, based on the total weight of the composition.
According to some embodiments of the invention, the fine aggregate is present in an amount of 30 to 60% by mass, based on the total weight of the composition.
According to some embodiments of the invention, the water is present in an amount of 5-20% by mass, e.g., 5%, 7%, 10%, 12%, 14%, 18%, 20% by weight of the total composition and any value therebetween.
According to some embodiments of the invention, the water is present in an amount of 5 to 15% by weight, based on the total weight of the composition.
According to some embodiments of the invention, the water reducing agent is present in an amount of 0-0.5% by mass, e.g. 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and any value in between, based on the total weight of the composition.
According to some embodiments of the invention, the water reducing agent is present in an amount of 0 to 0.3% by weight, based on the total weight of the composition.
According to some embodiments of the invention, the defoamer is present in an amount of 0-0.5% by mass, e.g., 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and any value therebetween, based on the total weight of the composition.
According to some embodiments of the invention, the defoamer is present in an amount of 0-0.3% by weight, based on the total weight of the composition.
In some preferred embodiments of the present invention, the composition comprises, by weight, 30 parts to 50 parts of a gelling material; 1-10 parts of polymer emulsion (broken and fixed) and/or redispersible polymer rubber powder; optionally 100-120 parts of coarse aggregate; 70-80 parts of fine aggregate; 15-18 parts of water; 0-0.1 part of water reducing agent; 0-0.1 part of defoaming agent.
In some preferred embodiments of the present invention, the composition is a concrete composition comprising, by weight, 30 parts to 50 parts of a cementitious material; 1-10 parts of polymer emulsion (broken and fixed) and/or redispersible polymer rubber powder; 100-120 parts of coarse aggregate; 70-80 parts of fine aggregate; 15-18 parts of water; 0-0.1 part of water reducing agent; 0-0.1 part of defoaming agent.
In some preferred embodiments of the present invention, the composition is a mortar composition comprising, in weight parts, 30 to 50 parts of a cementitious material; 1-10 parts of polymer emulsion (broken and fixed) and/or redispersible polymer rubber powder; 70-80 parts of fine aggregate; 15-18 parts of water; 0-0.1 part of water reducing agent; 0-0.1 part of defoaming agent.
According to some embodiments of the invention, the cementitious material is selected from one or more of pure portland cement, ordinary portland cement, composite cement, sulphoaluminate cement, aluminate cement, and mineral admixtures.
According to some embodiments of the invention, the coarse aggregate is selected from one or more of pebbles, crushed stones, slag and ceramsite.
According to some embodiments of the invention, the fine aggregate is selected from one or more of river sand, mountain sand, sea sand and machine-made sand.
According to some embodiments of the invention, the water reducing agent is selected from one or more of a naphthalene based water reducing agent and a polycarboxylic acid based water reducing agent.
According to some embodiments of the invention, the water comprises a polymer emulsion and water in a water reducing agent.
According to a second aspect of the invention, the prefabricated element comprises a composition according to the first aspect described above.
According to a third aspect of the present invention, a method for producing the prefabricated part comprises:
1) providing a composition according to the first aspect;
2) blending the composition to form a blend;
3) and forming and curing the mixture.
According to some embodiments of the invention, the mixing (2) means that the concrete mixing proportion is determined according to the selected polymer emulsion, the water reducing agent, the cement, the sand aggregate and the first formula requirement, then sand, the cementing material and the liquid phase are sequentially added into the mixer and are uniformly mixed according to a conventional process.
According to some embodiments of the invention, the curing is steam curing.
According to some embodiments of the present invention, the steam curing refers to a process of pouring the mixed mixture into a mold, performing a vibration and static curing process, and curing the mixture to a specific strength in a steam curing system.
According to some embodiments of the invention, the curing comprises atmospheric steam curing and high pressure steam curing.
According to some embodiments of the invention, the steam curing temperature is above the glass transition temperature of the polymer emulsion and/or redispersible polymer gum powder.
According to some embodiments of the invention, the temperature of the steam curing is 5-50 ℃ higher than the glass transition temperature of the polymer emulsion and/or the redispersible polymer gum powder, such as 5 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃ and the like.
According to some embodiments of the invention, the steam curing temperature is 10 to 30 ℃ above the glass transition temperature of the polymer emulsion and/or redispersible polymer powder.
In the present invention, by controlling the steam curing temperature to be higher than the above-mentioned range of the glass transition temperature, the fusion of the polymer in the concrete (mortar) to form a film can be promoted, and a continuous network structure of the polymer phase is formed, thereby obtaining high strength.
According to some embodiments of the invention, the steam curing temperature is 60 to 180 ℃.
According to some embodiments of the invention, the steam curing temperature is atmospheric steam curing, preferably the atmospheric steam curing temperature is 60-80 ℃.
According to some embodiments of the present invention, the steam curing temperature is high pressure steam curing, preferably the high pressure steam curing temperature is 120-.
According to some embodiments of the invention, the method for making the preform comprises the following specific steps:
1) the selected basic materials such as cement, sand, water reducing agent, polymer emulsion, defoaming agent and the like are weighed according to the mixing proportion. Then the sand stone and the cement are sequentially put into a stirrer for pre-stirring. The water reducing agent, the defoaming agent, the emulsion, the water and the like are uniformly mixed and then are put into a stirrer.
2) And after the concrete is uniformly stirred, pouring the concrete into a prefabricated part mould, and determining whether to vibrate according to the type of the concrete. After the concrete is formed, the concrete is statically maintained for a plurality of hours at normal temperature, and then is placed in a steam curing system for curing for a plurality of hours. And demolding after the target strength is achieved to obtain the polymer modified concrete prefabricated part.
According to a fourth aspect of the present invention, there is provided the use of the above-described composition or prefabricated element in building materials, in particular in the fields of bridges, tunnels, pipes, plants, railways, harbours and the like.
The polymer emulsion with high glass transition temperature is applied to a concrete (mortar) prefabricated part, and the concrete prefabricated part with excellent mechanical property, impermeability and durability is prepared in a steam curing mode. The method not only exerts the advantage that the high glass transition temperature polymer has little influence on the compressive strength of the concrete (mortar), but also can greatly improve the breaking strength, the impermeability and the durability of the concrete (mortar) through polymer film formation, and simultaneously overcomes the defects of rough aperture and large brittleness commonly existing in the existing steam-cured member.
Detailed Description
The invention is further illustrated by the following examples, but it is to be noted that the scope of the invention is not limited thereto, but is defined by the claims.
It should be particularly noted that two or more aspects (or embodiments) disclosed in the context of the present specification may be combined with each other at will, and thus form part of the original disclosure of the specification, and also fall within the scope of the present invention.
The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
Measurement of glass transition temperature: the glass transition temperature of the polymer emulsion is measured by Differential Scanning Calorimetry (DSC), firstly, the polymer emulsion is dried in vacuum, 10mg plus or minus 2mg of the dried polymer is taken into a differential scanning calorimeter and cooled to-30 ℃. Then the temperature was raised to 120 ℃ at a rate of 10 ℃/s and subsequently lowered to-30 ℃ at a rate of 10 ℃/s. And then, carrying out a cycle again, and analyzing the data of the second cycle to obtain the glass transition temperature of the polymer.
Raw materials for experiments
The standard cement is P.I 42.5 standard cement which is produced by the middle-linked cement company Limited and accords with the concrete admixture GB 8076-2008.
The preparation method of the styrene-acrylic emulsion with the glass transition temperature of 20 ℃, 30 ℃, 40 ℃, 52 ℃ and 70 ℃ respectively takes the emulsion with the glass transition temperature of 52 ℃ as an example, and the preparation method of the emulsion is summarized as follows: first, monomer emulsion A was prepared using 89.6g of deionized water, 152.1g of styrene, 52.1g of butyl acrylate, 5.6g of emulsifier, 4.2g of TPEG, initiator solution B was prepared using 116.7g of deionized water and 1.2g of sodium persulfate, solution C was prepared using 20.8g of deionized water and 0.4g of t-butyl hydroperoxide, and solution D was prepared using 12.5g of deionized water and 0.3g of sodium thiosulfate. Then, 70.8g of deionized water and 3.4g of an emulsifier as a base were put into a three-necked flask having a capacity of 1000mL and heated to 90 ℃. After the primer was heated to 90 ℃, the dropwise addition of the emulsion A and the solution B was started, and the dropwise addition of the emulsion A and the solution B was completed within 3.5 hours and 4 hours, respectively. After the solution A and the solution B are added, the solution C and the solution D are added after the temperature is kept for 30 minutes, and the solution A and the solution B are added within 2 hours. After the solution C and the solution D are dropwise added, the solution is gradually cooled to room temperature, and the solid content of the obtained emulsion is 40 +/-2%. The glass transition temperature of the polymer emulsion is regulated and controlled by changing the ratio of styrene to butyl acrylate, and the mass ratios of the styrene to the butyl acrylate in the styrene-acrylic emulsion at 20 ℃, 30 ℃, 40 ℃, 52 ℃ and 70 ℃ are respectively 1:0.85, 1:0.69, 1:0.53, 1:0.34 and 1: 0.05.
The styrene-acrylic polymer adhesive powder with the glass transition temperature of 52 ℃ is prepared from styrene-acrylic emulsion with the glass transition temperature of 52 ℃ by a spray drying method.
Coarse aggregate, broken stone and 5-20 mm continuous gradation.
Fine aggregate, river sand and fineness modulus of 2.3-2.9.
Example 1
(1) Weighing 33 parts of reference cement, 2 parts of folded and solidified styrene-acrylic emulsion with the glass transition temperature of 52 ℃, 110 parts of coarse aggregate, 75 parts of fine aggregate and 18 parts of tap water (including water in the styrene-acrylic emulsion);
(2) placing the cement, the fine aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic emulsion and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 60 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Example 2
(1) Weighing 33 parts of reference cement, 2 parts of styrene-acrylic polymer rubber powder with the glass transition temperature of 52 ℃, 110 parts of coarse aggregate, 75 parts of fine aggregate and 18 parts of tap water;
(2) placing the cement, the coarse aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic polymer rubber powder and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 60 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Example 3
(1) Weighing 33 parts of reference cement, 2 parts of folded and solidified styrene-acrylic emulsion with the glass transition temperature of 52 ℃, 110 parts of coarse aggregate, 75 parts of fine aggregate and 18 parts of tap water (including water in the styrene-acrylic emulsion);
(2) placing the cement, the coarse aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic emulsion and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 80 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Example 4
(1) Weighing 49 parts of reference cement, 3 parts of styrene-acrylic emulsion with the glass transition temperature of 52 ℃, 108 parts of coarse aggregate, 81 parts of fine aggregate and 18 parts of tap water (including water in the styrene-acrylic emulsion);
(2) placing the cement, the coarse aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic emulsion and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 60 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Example 5
(1) Weighing 49 parts of reference cement, 3 parts of styrene-acrylic polymer rubber powder with the glass transition temperature of 52 ℃, 108 parts of coarse aggregate, 81 parts of fine aggregate and 18 parts of tap water;
(2) placing the cement, the coarse aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic polymer rubber powder and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 60 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Example 6
(1) Weighing 49 parts of reference cement, 3 parts of styrene-acrylic emulsion with the glass transition temperature of 52 ℃, 108 parts of coarse aggregate, 81 parts of fine aggregate and 18 parts of tap water (including water in the styrene-acrylic emulsion);
(2) placing the cement, the coarse aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic emulsion and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 80 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Example 7
(1) Weighing 33 parts of reference cement, 2 parts of folded and solidified styrene-acrylic emulsion with the glass transition temperature of 40 ℃, 110 parts of coarse aggregate, 75 parts of fine aggregate and 18 parts of tap water (including water in the styrene-acrylic emulsion);
(2) placing the cement, the fine aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic emulsion and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 60 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Example 8
(1) Weighing 33 parts of reference cement, 2 parts of folded and solidified styrene-acrylic emulsion with the glass transition temperature of 52 ℃, 110 parts of coarse aggregate, 75 parts of fine aggregate and 18 parts of tap water (including water in the styrene-acrylic emulsion);
(2) placing the cement, the fine aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic emulsion and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 90 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Example 9
(1) Weighing 33 parts of reference cement, 2 parts of folded and solidified styrene-acrylic emulsion with the glass transition temperature of 52 ℃, 110 parts of coarse aggregate, 75 parts of fine aggregate and 18 parts of tap water (including water in the styrene-acrylic emulsion);
(2) placing the cement, the fine aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic emulsion and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 50 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Example 10
(1) Weighing 33 parts of reference cement, 2 parts of folded and solidified styrene-acrylic emulsion with the glass transition temperature of 70 ℃, 110 parts of coarse aggregate, 75 parts of fine aggregate and 18 parts of tap water (including water in the styrene-acrylic emulsion);
(2) placing the cement, the fine aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic emulsion and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 80 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Example 11
(1) Weighing 33 parts of reference cement, 2 parts of folded and solidified styrene-acrylic emulsion with the glass transition temperature of 30 ℃, 110 parts of coarse aggregate, 75 parts of fine aggregate and 18 parts of tap water (including water in the styrene-acrylic emulsion);
(2) placing the cement, the fine aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic emulsion and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 60 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Comparative example 1
(1) Weighing 33 parts of reference cement, 110 parts of coarse aggregate, 75 parts of fine aggregate and 18 parts of tap water;
(2) placing the cement, the fine aggregate and the fine aggregate into a stirrer for pre-stirring, and then placing water into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 60 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Comparative example 2
(1) Weighing 49 parts of reference cement, 108 parts of coarse aggregate, 81 parts of fine aggregate and 18 parts of tap water;
(2) placing the cement, the coarse aggregate and the fine aggregate into a stirrer for pre-stirring, and then mixing water and placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 60 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Comparative example 3
(1) Weighing 33 parts of reference cement, 2 parts of folded and solidified styrene-acrylic emulsion with the glass transition temperature of 20 ℃, 110 parts of coarse aggregate, 75 parts of fine aggregate and 18 parts of tap water (including water in the styrene-acrylic emulsion);
(2) placing the cement, the fine aggregate and the fine aggregate into a stirrer for pre-stirring, then uniformly mixing the styrene-acrylic emulsion and tap water, and then placing the mixture into the stirrer for stirring;
(3) after being stirred evenly, the mixture is poured into a standard mould for testing the compressive strength and the flexural strength of the concrete and is covered with a film for static curing for 2 hours. After the static curing is finished, the concrete standard test block is placed in a normal pressure environment with the temperature of 60 ℃ and the relative humidity of not less than 90 percent for curing for 10 hours, then is taken out and is transferred to a concrete standard curing room.
Test example 1
Using the concrete blocks supported in examples 1 to 11 and comparative examples 1 to 3, the compressive strength was measured after curing to an age of 1d, 3d, 7d and 28 d. The results are shown in Table 1.
TABLE 1 compressive Strength of Polymer modified concrete steam-cured test pieces
Figure BDA0002515075990000131
Test example 2
The concrete blocks supported in examples 1 to 11 and comparative examples 1 to 3 were cured to age 1d, 7d and 28d to test flexural strength. The results are shown in Table 2.
TABLE 2 flexural strength of Polymer-modified concrete steam-cured test pieces
Figure BDA0002515075990000132
Figure BDA0002515075990000141
The test results of the concrete compressive strength and the concrete flexural strength show that: above the glass transition temperature (T) of the polymer at curing temperaturesg) In the case of (3), high T is incorporatedgThe polymer emulsion or the rubber powder obviously improves the flexural strength of the concrete, and has no negative influence on the compressive strength of the concrete. The polymer T being the same as the inorganic component of the concretegThe higher the strength of the concrete 28d (examples 1, 7, 10 and 11). Incorporation of TgFor the same polymer emulsion, the higher the steam curing temperature, the higher the strength of the concrete 28d (examples 1, 3 and 8). However, it should be noted that too high curing temperature (as in example 8) causes problems of low strength and high brittleness of the concrete in long-term service. Therefore, from this viewpoint, the curing temperature of the member may be slightly higher than the glass transition temperature of the polymer.
It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not set any limit to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.

Claims (5)

1. A method of making a prefabricated component comprising:
1) providing a composition;
2) mixing the composition to form a blend;
3) molding and maintaining the mixture;
the composition comprises 30-50 parts by weight of a cementing material; 1-10 parts of polymer emulsion (broken and fixed) and/or redispersible polymer rubber powder; 70-80 parts of fine aggregate; 15-18 parts of water; 0-0.1 part of water reducing agent; 0-0.1 part of defoaming agent; optionally 100-120 parts of coarse aggregate;
the glass transition temperature of the polymer emulsion and/or the redispersible polymer rubber powder is 52-70 ℃;
the polymer emulsion is selected from one or more of styrene-acrylic emulsion, butylbenzene emulsion, ethylene-vinyl acetate copolymer emulsion and acrylate emulsion;
the redispersible polymer rubber powder is selected from one or more of redispersible styrene-acrylic rubber powder, redispersible styrene-butadiene rubber powder, redispersible ethylene-vinyl acetate copolymer rubber powder, redispersible styrene rubber powder and redispersible acrylic ester rubber powder;
the curing is steam curing, and the temperature of the steam curing is 15-30 ℃ higher than the glass transition temperature of the polymer emulsion and/or the redispersible polymer rubber powder.
2. The method according to claim 1, wherein the cementitious material is selected from one or more of pure portland cement, ordinary portland cement, composite cement, sulphoaluminate cement, aluminate cement, and mineral admixtures;
and/or the coarse aggregate is selected from one or more of pebbles, crushed stones, slag and ceramsite;
and/or the fine aggregate is selected from one or more of river sand, mountain sand, sea sand and machine-made sand;
and/or the water reducing agent is selected from one or more of a naphthalene water reducing agent and a polycarboxylic acid water reducing agent.
3. The method of claim 1, wherein the steam curing comprises atmospheric steam curing and/or high pressure steam curing.
4. Use of a prefabricated element prepared according to the method of any one of claims 1 to 3 in a building material.
5. The application according to claim 4, wherein the application is in the field of bridges, tunnels, pipes, plants, railways, ports.
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