CN112279590A - Sulfate erosion resistant concrete and preparation method thereof - Google Patents

Sulfate erosion resistant concrete and preparation method thereof Download PDF

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CN112279590A
CN112279590A CN202011197497.2A CN202011197497A CN112279590A CN 112279590 A CN112279590 A CN 112279590A CN 202011197497 A CN202011197497 A CN 202011197497A CN 112279590 A CN112279590 A CN 112279590A
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sulfate
stirring
solution
silica
concrete
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董浩
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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
    • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
    • C04B24/40—Compounds containing silicon, titanium or zirconium or other organo-metallic compounds; Organo-clays; Organo-inorganic complexes
    • C04B24/42—Organo-silicon compounds
    • C04B24/425—Organo-modified inorganic compounds, e.g. organo-clays
    • 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
    • C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • C04B40/0028—Aspects relating to the mixing step of the mortar preparation
    • C04B40/0039—Premixtures of ingredients
    • C04B40/0046—Premixtures of ingredients characterised by their processing, e.g. sequence of mixing the ingredients when preparing the premixtures
    • 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
    • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/60—Agents for protection against chemical, physical or biological attack
    • C04B2103/61—Corrosion inhibitors
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/20—Resistance against chemical, physical or biological attack
    • C04B2111/2015—Sulfate resistance
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • 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

Abstract

The invention relates to the technical field of concrete, and discloses sulfate erosion resistant concrete and a preparation method thereof. The cement-based anti-corrosion coating comprises, by mass, 20-23% of portland cement, 15-18% of crushed stone, 10-15% of natural sand, 8-12% of glass fiber, 5-8% of mineral powder, 5-10 parts of anti-sulfate composite particles, 1-3% of a polycarboxylic acid water reducing agent and the balance of water; adding the portland cement, the broken stone and the natural sand into a stirrer, and uniformly stirring and mixing to obtain a premix; adding a polycarboxylate superplasticizer into water, stirring and dissolving to obtain a polycarboxylate superplasticizer solution, adding the polycarboxylate superplasticizer solution into the premix for wet mixing, then adding glass fibers, mineral powder and sulfate-resistant composite particles, and continuously stirring and uniformly mixing to obtain the polycarboxylate superplasticizer. The concrete prepared by the invention has excellent sulfate erosion resistance.

Description

Sulfate erosion resistant concrete and preparation method thereof
Technical Field
The invention relates to the technical field of concrete, in particular to sulfate erosion resistant concrete and a preparation method thereof.
Background
The cement-based material brings great convenience to daily life of people and is the most widely applied building material in the world at present. The durability of the cement-based material, including frost resistance, impermeability, carbonation resistance, chloride ion resistance, sulfate erosion resistance and the like, has obvious influence on the service life of the cement-based material. In a complex service environment, harmful substances in the external environment are immersed in the cement-based material to have irrecoverable influence on the service performance of the cement-based material, so that the durability of the cement-based material is reduced, the performance of the cement-based material is lost, and the service life of the cement-based material is shortened. After the cement-based material loses the service performance, a large amount of construction waste is generated, and huge resources and energy waste is caused. According to statistics, the growth amount of the construction waste generated in China is at least more than 3 hundred million tons. Therefore, the durability of the cement-based material is improved, the service life of the cement-based material is prolonged, and the cement-based material has important significance for reducing the generation of building material garbage and reducing the waste of resources and energy. The attack of sulfate attack on cement-based materials is one of the main reasons affecting their durability. A large amount of sulfate exists in seawater, low water, river water and saline-alkali soil in nature. In the service process of the cement-based material, external sulfate invades the interior of the cement-based material and reacts with calcium hydroxide which is a product of hydration of cement and mono-sulfur hydrated calcium aluminum sulfate or tricalcium aluminate which is an incompletely hydrated mineral, the generated ettringite and gypsum cause the expansion and cracking of the cement-based structure, and the repeated weight crystallization of the sulfate in the cement-based material in a dry and wet environment also causes the expansion and cracking of the hardened cement-based material. Sulfate attack is believed to be one of the major factors causing failure cracking of cement-based materials. In China, a plurality of buildings are corroded and damaged by sulfate, and a large part of the buildings are seriously endangered to the safe use of the buildings, and the corrosion of the buildings by the sulfate is a very serious and common phenomenon in coastal areas, heavy saline areas in the west and northeast areas of China. In most buildings constructed by cement-based materials on coasts and ports, dams, tunnels, power stations and the like in northwest and southwest areas have serious sulfate erosion phenomena, so that potential safety hazards of service are caused.
For example, chinese patent publication No. CN108383457 discloses a high-strength heavy slag permeable concrete, which comprises portland cement, coarse aggregate, mineral powder, fly ash, an additive, and water; the used reinforced heavy slag is high-strength slurry formed by covering a layer of alkene on the surface of common heavy slag to form a shell-making reinforcing effect, so that the compressive strength and the water permeability of concrete are improved; also, for example, chinese patent publication No. CN111704410 discloses a high-performance machine-made sand concrete and a preparation method thereof, comprising portland cement, fly ash, mineral powder, silica fume, machine-made sand, crushed stone, a high-efficiency water reducing agent, and water; the concrete has the advantages of overcoming the limitations of high viscosity, poor fluidity and difficult pumping of the machine-made sand high-strength concrete. The concrete prepared by the technical scheme of the patent is common concrete used in the market, does not have sulfate corrosion resistance, and is difficult to use in coastal areas with high sulfate content.
Disclosure of Invention
The invention provides sulfate corrosion resistant concrete and a preparation method thereof, aiming at overcoming the problem that the existing concrete is not resistant to sulfate corrosion. The concrete of the invention has excellent sulfate erosion resistance.
The purpose of the invention is realized by the following technical scheme:
the sulfate erosion resistant concrete comprises the following components in percentage by mass
20-23% of Portland cement, 15-18% of broken stone, 10-15% of natural sand, 8-12% of glass fiber, 5-8% of mineral powder, 5-10% of sulfate-resistant composite particles, 1-3% of polycarboxylic acid water reducing agent and the balance of water.
The invention takes portland cement as the main component of concrete, macadam as coarse aggregate and natural sand as fine aggregate; the compressive strength and the cracking resistance of the concrete are improved by adding glass fibers and mineral powder into the concrete; in the service process of the cement-based material, external sulfate invades the interior of the cement-based material and reacts with calcium hydroxide which is a product of hydration of cement and mono-sulfur hydrated calcium aluminum sulfate or tricalcium aluminate which is an incompletely hydrated mineral, and the cement-based structure is expanded and cracked due to ettringite and gypsum generated by the reaction.
Preferably, the crushed stone has a particle size of 16-20 mm.
Preferably, the fineness modulus of the natural sand is 2.5-3.0.
Preferably, the method for preparing the anti-sulfate composite particle comprises the following steps:
s1, adding an epoxy silane coupling agent into a mixed solution of ethanol and water, adjusting the pH value of the system to 3-5, heating in a water bath to 50-60 ℃, stirring and hydrolyzing to obtain a hydrolysis solution, adding nano-silica into the hydrolysis solution, stirring and reacting for 1-3h, centrifuging, washing and drying to obtain coupling agent modified nano-silica, adding the coupling agent modified nano-silica into a carboxymethyl chitosan aqueous solution, then adding a stannic chloride catalyst, heating to 80-85 ℃, stirring and reacting for 2-5h, centrifuging, washing and drying to obtain surface modified nano-silica;
s2, adding 2-methylimidazole into the methanol solution, stirring and dissolving, then adding the surface modified nano-silica, and stirring and mixing uniformly to obtain a suspension; adding Zn (NO)3)2·6H2Adding O into a methanol solution, stirring and dissolving to obtain a zinc nitrate solution, dropwise adding the zinc nitrate solution into the suspension, stirring and reacting for 2-5h, centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particles;
s3, adding barium nitrate into deionized water, stirring and dissolving to obtain a barium nitrate solution, adding the metal organic framework nanosheet-silicon dioxide composite particles into the barium nitrate solution, soaking for 15-20h at room temperature, centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particles loaded with barium nitrate; adding the barium nitrate-loaded metal organic framework nanosheet-silicon dioxide composite particle into a carboxymethyl cellulose solution, stirring and mixing uniformly, soaking for 5-10h at room temperature, centrifuging, washing and drying to obtain the sulfate-resistant composite particle.
The preparation method of the sulfate-resistant composite particle comprises the steps of firstly preparing a porous metal organic framework nanosheet by taking 2-methylimidazole and zinc nitrate hexahydrate as reaction monomers, using the porous metal organic framework nanosheet as a carrier of barium nitrate, loading the barium nitrate in a hole structure of the metal organic framework nanosheet, then soaking the metal organic framework nanosheet loaded with the barium nitrate in a carboxymethyl cellulose solution, taking out the metal organic framework nanosheet, and drying to form a layer of carboxymethyl cellulose film on the surface of the metal organic framework nanosheet, so that the metal organic framework nanosheet with the sulfate corrosion resistance is obtained. The sulfate erosion resistance principle is that when an external sulfate solution enters the interior of concrete, barium ions released by a metal organic framework loaded with barium nitrate react with sulfate radicals to generate precipitates, the precipitates are filled in gaps of the concrete, the sulfate ions can be removed, generated barium sulfate insoluble substances can also fill the gaps in the concrete, and the barium sulfate can not influence the mechanical property of the concrete, so that the sulfate erosion resistance effect is achieved. In addition, the carboxymethyl cellulose film is coated on the surface of the metal organic framework nanosheet, so that the loss of barium salt on the metal organic framework nanosheet in the concrete preparation process can be reduced, the barium salt is loaded on the metal organic framework nanosheet and is uniformly dispersed in the concrete, and in the process of taking the concrete after forming, the carboxymethyl cellulose film covered on the upper surface of the metal organic framework nanosheet can be completely dissolved and disappeared after the carboxymethyl cellulose is contacted with water for a long time, so that barium ions and sulfate ions are released to perform precipitation reaction, and the sulfate entering the concrete from the outside is eliminated. The porous metal organic framework nanosheet is different from a common porous material, the pore structure on the common porous material is a non-through pore structure, the barium salt loaded in the non-through pore structure has low release efficiency, the reaction of the barium salt and sulfate radical is influenced, and the sulfate corrosion resistance of concrete is further reduced. According to the invention, the porous structure of the porous metal organic framework nanosheet is a two-port through porous structure, and the porous structure is used as a carrier of barium salt, so that the barium salt can be endowed with higher release efficiency in concrete, the reaction of sulfate radicals and barium ions is promoted, and the reaction of the sulfate radicals and calcium hydroxide serving as a hydration product of cement is avoided.
Further, the problem that the porous metal organic framework nanosheets release barium ions to eliminate sulfate ions is that the quantity of the barium ions loaded on the porous metal organic framework nanosheets is limited, a large amount of barium ions are consumed in the reaction with external sulfate radicals, the content of the barium ions in the concrete is gradually reduced along with the prolonging of time, the sulfate resistance of the concrete is gradually reduced, and the concrete cannot resist sulfate erosion for a long time. Another problem is that the porous metal organic framework nano-sheet is hydrophobic, which is not beneficial to the loading of water-soluble barium salt, and is also not beneficial to the uniform dispersion of the metal organic framework nano-sheet in concrete. In order to solve the two problems, carboxymethyl chitosan is grafted on the surface of nano silicon dioxide, so that carboxyl and hydroxyl groups are loaded on the surface of the nano silicon dioxide, then the nano silicon dioxide loaded with carboxyl on the surface is combined on a metal organic framework nano sheet, and hydrophilic carboxyl and hydroxyl are loaded on the metal organic framework nano sheet, so that the metal organic framework nano sheet is endowed with good hydrophilic performance, and the loading capacity of barium salt and the uniformity of dispersion of the metal organic framework nano sheet in concrete are improved. On the other hand, carboxyl loaded on the metal organic framework nano sheet is ionized in water to enable the surface of the metal organic framework nano sheet to be negatively charged, so that the anion sulfate radicals are repelled, a large amount of external sulfate is prevented from entering the interior of the concrete, a small amount of sulfate enters the interior of the concrete and reacts with barium ions released by the metal organic framework nano sheet, the concrete can resist the corrosion of the sulfate for a long time, and the service life of the concrete is further prolonged.
Preferably, the mass ratio of the coupling agent modified nano silica to the carboxymethyl chitosan in the step S1 is 1: 0.3-0.8.
Preferably, the mass ratio of the 2-methylimidazole to the surface-modified nano-silica in the step S2 is 1: 0.4-0.7.
Preferably, the mass concentration of the barium nitrate solution in the step S3 is 0.5-5%.
Preferably, the mass concentration of the carboxymethyl cellulose solution in the step S3 is 2.5-4%.
The preparation method of the sulfate erosion resistant concrete comprises the following steps:
adding the portland cement, the broken stone and the natural sand into a stirrer, and uniformly stirring and mixing to obtain a premix; adding a polycarboxylate superplasticizer into water, stirring and dissolving to obtain a polycarboxylate superplasticizer solution, adding the polycarboxylate superplasticizer solution into the premix for wet mixing, then adding glass fibers, mineral powder and sulfate-resistant composite particles, and continuously stirring and uniformly mixing to obtain the polycarboxylate superplasticizer.
Detailed Description
The technical solutions of the present invention will be described clearly and completely below, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, belong to the scope of the present invention.
In the specific embodiment, the particle size of the crushed stone is 16-20 mm; the fineness modulus of the natural sand is 2.5-3.0.
Example 1
The preparation method of the anti-sulfate composite particle comprises the following steps:
s1, uniformly mixing ethanol and water according to the volume ratio of 1:0.2 to obtain a mixed solution of the ethanol and the water, adding an epoxy silane coupling agent KH560 into the mixed solution of the ethanol and the water, wherein the mass ratio of the epoxy silane coupling agent KH560 to the mixed solution is 1:30, adjusting the pH value of the system to 5, heating in a water bath to 50 ℃, stirring and hydrolyzing to obtain a hydrolysate, adding nano-silica into the hydrolysate according to the mass-volume ratio of 1g/50mL, stirring and reacting for 2.5h, centrifuging, washing and drying to obtain coupling agent modified nano-silica;
adding coupling agent modified nano-silica into a carboxymethyl chitosan aqueous solution with the mass concentration of 2.5%, wherein the mass ratio of the coupling agent modified nano-silica to the carboxymethyl chitosan is 1:0.7, then adding a tin tetrachloride catalyst, wherein the addition amount of the tin tetrachloride catalyst is 5% of the mass of the carboxymethyl chitosan, heating to 85 ℃, stirring for reaction for 4 hours, centrifuging, washing and drying to obtain surface modified nano-silica;
s2, adding 2-methylimidazole into a methanol solution according to the mass-volume ratio of 1g/25mL, stirring and dissolving, then adding surface modified nano-silica, wherein the mass ratio of 2-methylimidazole to surface modified nano-silica is 1:0.6, and stirring and mixing uniformly to obtain a suspension; adding Zn (NO)3)2·6H2Adding O into a methanol solution according to the mass-to-volume ratio of 1g/20mL, stirring and dissolving to obtain a zinc nitrate solution, dropwise adding the zinc nitrate solution into the suspension, wherein the mixing mass ratio of zinc nitrate to 2-methylimidazole is 1:9, stirring and reacting for 4 hours, and centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particle;
s3, adding barium nitrate into deionized water, stirring and dissolving to prepare a barium nitrate solution with the mass concentration of 4.0%, adding the metal organic framework nanosheet-silicon dioxide composite particle into the barium nitrate solution, soaking for 18 hours at room temperature, centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particle loaded with barium nitrate; adding the barium nitrate-loaded metal organic framework nanosheet-silicon dioxide composite particle into a carboxymethyl cellulose solution with the mass concentration of 3.5%, stirring and mixing uniformly, soaking for 9 hours at room temperature, centrifuging, washing and drying to obtain the sulfate-resistant composite particle.
The sulfate erosion resistant concrete comprises the following components in percentage by mass
22% of portland cement (conch P.042.5), 17% of broken stone, 14% of natural sand, 10% of glass fiber, 7% of mineral powder, 9 parts of sulfate-resistant composite particles, 2% of polycarboxylic acid water reducing agent and the balance of water.
The preparation method of the sulfate erosion resistant concrete comprises the following steps: adding the portland cement, the broken stone and the natural sand into a stirrer, and uniformly stirring and mixing to obtain a premix; adding a polycarboxylate superplasticizer into water, stirring and dissolving to obtain a polycarboxylate superplasticizer solution, adding the polycarboxylate superplasticizer solution into the premix for wet mixing, then adding glass fibers, mineral powder and sulfate-resistant composite particles, and continuously stirring and uniformly mixing to obtain the polycarboxylate superplasticizer.
Example 2
The preparation method of the anti-sulfate composite particle comprises the following steps:
s1, uniformly mixing ethanol and water according to the volume ratio of 1:0.2 to obtain a mixed solution of the ethanol and the water, adding an epoxy silane coupling agent KH560 into the mixed solution of the ethanol and the water, wherein the mass ratio of the epoxy silane coupling agent KH560 to the mixed solution is 1:30, adjusting the pH value of the system to 3, heating in a water bath to 60 ℃, stirring and hydrolyzing to obtain a hydrolysate, adding nano-silica into the hydrolysate according to the mass-volume ratio of 1g/50mL, stirring and reacting for 1.5h, centrifuging, washing and drying to obtain coupling agent modified nano-silica;
adding coupling agent modified nano-silica into a carboxymethyl chitosan aqueous solution with the mass concentration of 2.5%, wherein the mass ratio of the coupling agent modified nano-silica to the carboxymethyl chitosan is 1:0.4, then adding a stannic chloride catalyst, wherein the addition amount of the stannic chloride catalyst is 5% of the mass of the carboxymethyl chitosan, heating to 80 ℃, stirring for reaction for 2.5h, and obtaining surface modified nano-silica through centrifugation, washing and drying;
s2, adding 2-methylimidazole into a methanol solution according to the mass-volume ratio of 1g/25mL, stirring and dissolving, then adding surface modified nano-silica, wherein the mass ratio of 2-methylimidazole to surface modified nano-silica is 1:0.5, and stirring and mixing uniformly to obtain a suspension; adding Zn (NO)3)2·6H2Adding O into a methanol solution according to the mass-to-volume ratio of 1g/20mL, stirring and dissolving to obtain a zinc nitrate solution, dropwise adding the zinc nitrate solution into the suspension, wherein the mixing mass ratio of zinc nitrate to 2-methylimidazole is 1:9, stirring and reacting for 2.5h, and centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particle;
s3, adding barium nitrate into deionized water, stirring and dissolving to prepare a barium nitrate solution with the mass concentration of 1.0%, adding the metal organic framework nanosheet-silicon dioxide composite particle into the barium nitrate solution, soaking for 16 hours at room temperature, centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particle loaded with barium nitrate; adding the barium nitrate-loaded metal organic framework nanosheet-silicon dioxide composite particle into a carboxymethyl cellulose solution with the mass concentration of 3.0%, stirring and mixing uniformly, soaking for 6 hours at room temperature, centrifuging, washing and drying to obtain the sulfate-resistant composite particle.
The sulfate erosion resistant concrete comprises the following components in percentage by mass
21% of portland cement (conch P.042.5), 16% of broken stone, 12% of natural sand, 9% of glass fiber, 6% of mineral powder, 6% of sulfate-resistant composite particles, 2% of polycarboxylic acid water reducing agent and the balance of water.
The preparation method of the sulfate erosion resistant concrete comprises the following steps: adding the portland cement, the broken stone and the natural sand into a stirrer, and uniformly stirring and mixing to obtain a premix; adding a polycarboxylate superplasticizer into water, stirring and dissolving to obtain a polycarboxylate superplasticizer solution, adding the polycarboxylate superplasticizer solution into the premix for wet mixing, then adding glass fibers, mineral powder and sulfate-resistant composite particles, and continuously stirring and uniformly mixing to obtain the polycarboxylate superplasticizer.
Example 3
The preparation method of the anti-sulfate composite particle comprises the following steps:
s1, uniformly mixing ethanol and water according to the volume ratio of 1:0.2 to obtain a mixed solution of the ethanol and the water, adding an epoxy silane coupling agent KH560 into the mixed solution of the ethanol and the water, wherein the mass ratio of the epoxy silane coupling agent KH560 to the mixed solution is 1:30, adjusting the pH value of the system to 4, heating in a water bath to 55 ℃, stirring and hydrolyzing to obtain a hydrolysate, adding nano-silica into the hydrolysate according to the mass-volume ratio of 1g/50mL, stirring and reacting for 3 hours, centrifuging, washing and drying to obtain the coupling agent modified nano-silica;
adding coupling agent modified nano-silica into a carboxymethyl chitosan aqueous solution with the mass concentration of 2.5%, wherein the mass ratio of the coupling agent modified nano-silica to the carboxymethyl chitosan is 1:0.8, then adding a stannic chloride catalyst, wherein the addition amount of the stannic chloride catalyst is 5% of the mass of the carboxymethyl chitosan, heating to 83 ℃, stirring for reaction for 5 hours, centrifuging, washing and drying to obtain surface modified nano-silica;
s2, adding 2-methylimidazole into a methanol solution according to the mass-volume ratio of 1g/25mL, stirring and dissolving, then adding surface modified nano-silica, wherein the mass ratio of 2-methylimidazole to surface modified nano-silica is 1:0.7, and stirring and mixing uniformly to obtain a suspension; adding Zn (NO)3)2·6H2Adding O into a methanol solution according to the mass-to-volume ratio of 1g/20mL, stirring and dissolving to obtain a zinc nitrate solution, dropwise adding the zinc nitrate solution into the suspension, wherein the mixing mass ratio of zinc nitrate to 2-methylimidazole is 1:9, stirring and reacting for 5 hours, and centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particle;
s3, adding barium nitrate into deionized water, stirring and dissolving to prepare a barium nitrate solution with the mass concentration of 5.0%, adding the metal organic framework nanosheet-silicon dioxide composite particle into the barium nitrate solution, soaking for 20 hours at room temperature, centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particle loaded with barium nitrate; adding the barium nitrate-loaded metal organic framework nanosheet-silicon dioxide composite particle into a carboxymethyl cellulose solution with the mass concentration of 4.0%, stirring and mixing uniformly, soaking at room temperature for 10 hours, centrifuging, washing and drying to obtain the sulfate-resistant composite particle.
The sulfate erosion resistant concrete comprises the following components in percentage by mass
23% of portland cement (conch P.042.5), 18% of broken stone, 15% of natural sand, 12% of glass fiber, 8% of mineral powder, 10 parts of sulfate-resistant composite particles, 3% of polycarboxylic acid water reducing agent and the balance of water.
The preparation method of the sulfate erosion resistant concrete comprises the following steps: adding the portland cement, the broken stone and the natural sand into a stirrer, and uniformly stirring and mixing to obtain a premix; adding a polycarboxylate superplasticizer into water, stirring and dissolving to obtain a polycarboxylate superplasticizer solution, adding the polycarboxylate superplasticizer solution into the premix for wet mixing, then adding glass fibers, mineral powder and sulfate-resistant composite particles, and continuously stirring and uniformly mixing to obtain the polycarboxylate superplasticizer.
Example 4
The preparation method of the anti-sulfate composite particle comprises the following steps:
s1, uniformly mixing ethanol and water according to the volume ratio of 1:0.2 to obtain a mixed solution of the ethanol and the water, adding an epoxy silane coupling agent KH560 into the mixed solution of the ethanol and the water, wherein the mass ratio of the epoxy silane coupling agent KH560 to the mixed solution is 1:30, adjusting the pH value of the system to 4, heating in a water bath to 55 ℃, stirring and hydrolyzing to obtain a hydrolysate, adding nano-silica into the hydrolysate according to the mass-volume ratio of 1g/50mL, stirring and reacting for 1h, centrifuging, washing and drying to obtain the coupling agent modified nano-silica;
adding coupling agent modified nano-silica into a carboxymethyl chitosan aqueous solution with the mass concentration of 2.5%, wherein the mass ratio of the coupling agent modified nano-silica to the carboxymethyl chitosan is 1:0.3, then adding a stannic chloride catalyst, wherein the addition amount of the stannic chloride catalyst is 5% of the mass of the carboxymethyl chitosan, heating to 83 ℃, stirring for reaction for 2 hours, centrifuging, washing and drying to obtain surface modified nano-silica;
s2, adding 2-methylimidazole into a methanol solution according to the mass-volume ratio of 1g/25mL, stirring and dissolving, then adding surface modified nano-silica, wherein the mass ratio of 2-methylimidazole to surface modified nano-silica is 1:0.4, and stirring and mixing uniformly to obtain a suspension; adding Zn (NO)3)2·6H2Adding O into a methanol solution according to the mass-to-volume ratio of 1g/20mL, stirring and dissolving to obtain a zinc nitrate solution, dropwise adding the zinc nitrate solution into the suspension, wherein the mixing mass ratio of zinc nitrate to 2-methylimidazole is 1:9, stirring and reacting for 2 hours, and centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particle;
s3, adding barium nitrate into deionized water, stirring and dissolving to prepare a barium nitrate solution with the mass concentration of 0.5%, adding the metal organic framework nanosheet-silicon dioxide composite particle into the barium nitrate solution, soaking for 15 hours at room temperature, centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particle loaded with barium nitrate; adding the barium nitrate-loaded metal organic framework nanosheet-silicon dioxide composite particle into a carboxymethyl cellulose solution with the mass concentration of 2.5%, stirring and mixing uniformly, soaking for 5 hours at room temperature, centrifuging, washing and drying to obtain the sulfate-resistant composite particle.
The sulfate erosion resistant concrete comprises the following components in percentage by mass
20% of portland cement (conch P.042.5), 15% of broken stone, 10% of natural sand, 8% of glass fiber, 5% of mineral powder, 5 parts of sulfate-resistant composite particles, 1% of polycarboxylic acid water reducing agent and the balance of water.
The preparation method of the sulfate erosion resistant concrete comprises the following steps: adding the portland cement, the broken stone and the natural sand into a stirrer, and uniformly stirring and mixing to obtain a premix; adding a polycarboxylate superplasticizer into water, stirring and dissolving to obtain a polycarboxylate superplasticizer solution, adding the polycarboxylate superplasticizer solution into the premix for wet mixing, then adding glass fibers, mineral powder and sulfate-resistant composite particles, and continuously stirring and uniformly mixing to obtain the polycarboxylate superplasticizer.
Example 5
The preparation method of the anti-sulfate composite particle comprises the following steps:
s1, uniformly mixing ethanol and water according to the volume ratio of 1:0.2 to obtain a mixed solution of the ethanol and the water, adding an epoxy silane coupling agent KH560 into the mixed solution of the ethanol and the water, wherein the mass ratio of the epoxy silane coupling agent KH560 to the mixed solution is 1:30, adjusting the pH value of the system to 4, heating in a water bath to 55 ℃, stirring and hydrolyzing to obtain a hydrolysate, adding nano-silica into the hydrolysate according to the mass-volume ratio of 1g/50mL, stirring and reacting for 2 hours, centrifuging, washing and drying to obtain the coupling agent modified nano-silica;
adding coupling agent modified nano-silica into a carboxymethyl chitosan aqueous solution with the mass concentration of 2.5%, wherein the mass ratio of the coupling agent modified nano-silica to the carboxymethyl chitosan is 1:0.5, then adding a stannic chloride catalyst, wherein the addition amount of the stannic chloride catalyst is 5% of the mass of the carboxymethyl chitosan, heating to 83 ℃, stirring for reaction for 4 hours, centrifuging, washing and drying to obtain surface modified nano-silica;
s2, adding 2-methylimidazole into a methanol solution according to the mass-volume ratio of 1g/25mL, stirring and dissolving, then adding surface modified nano-silica, wherein the mass ratio of 2-methylimidazole to surface modified nano-silica is 1:0.5, and stirring and mixing uniformly to obtain a suspension; adding Zn (NO)3)2·6H2Adding O into a methanol solution according to the mass-to-volume ratio of 1g/20mL, stirring and dissolving to obtain a zinc nitrate solution, dropwise adding the zinc nitrate solution into the suspension, wherein the mixing mass ratio of zinc nitrate to 2-methylimidazole is 1:9, stirring and reacting for 3.5 hours, and centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particle;
s3, adding barium nitrate into deionized water, stirring and dissolving to prepare a barium nitrate solution with the mass concentration of 3.0%, adding the metal organic framework nanosheet-silicon dioxide composite particle into the barium nitrate solution, soaking for 17 hours at room temperature, centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particle loaded with barium nitrate; adding the barium nitrate-loaded metal organic framework nanosheet-silicon dioxide composite particle into a carboxymethyl cellulose solution with the mass concentration of 3.0%, stirring and mixing uniformly, soaking for 7 hours at room temperature, centrifuging, washing and drying to obtain the sulfate-resistant composite particle.
The sulfate erosion resistant concrete comprises the following components in percentage by mass:
22% of portland cement (conch P.042.5), 16% of broken stone, 12% of natural sand, 10% of glass fiber, 6% of mineral powder, 7 parts of sulfate-resistant composite particles, 2% of polycarboxylic acid water reducing agent and the balance of water.
The preparation method of the sulfate erosion resistant concrete comprises the following steps: adding the portland cement, the broken stone and the natural sand into a stirrer, and uniformly stirring and mixing to obtain a premix; adding a polycarboxylate superplasticizer into water, stirring and dissolving to obtain a polycarboxylate superplasticizer solution, adding the polycarboxylate superplasticizer solution into the premix for wet mixing, then adding glass fibers, mineral powder and sulfate-resistant composite particles, and continuously stirring and uniformly mixing to obtain the polycarboxylate superplasticizer.
Comparative example
The comparative example is different from example 1 in that the anti-sulfate composite particles are not added to the concrete.
Comparative example
The control example is sulfate-resistant concrete produced by concrete Co., Ltd. in Zhejiang.
Firstly, mechanical property testing:
1. compressive strength: the compression strength test is carried out on the non-standard test block by referring to GB/T50081 and 2002 Standard test method for mechanical properties of common concrete. The experimental instrument is a pressure tester with the range of 600 kN. The compressive strength test method operates as follows: the shaped side of a test block of 100mm by 100mm is placed in the test center of a compression testing machine, and the testing machine is started and continuously and uniformly loaded at a loading rate of 0.1-0.15 MPa/s. When the test piece changesAnd recording the load value after the destructive damage. The compressive strength of the test piece was calculated as follows: f is 0.95F/A; wherein F represents the compressive strength (MPa) of the test piece, F represents the breaking load (N) of the test piece, and A represents the time load area (mm)2)。
2. Breaking strength: the flexural strength of a standard test piece of 100mm multiplied by 400mm is tested by referring to GB/T50081-2002 Standard test methods for mechanical properties of ordinary concrete. The instrument is a hydraulic universal testing machine, the operation method is that the molding side of the test piece faces upwards, the contact surface between the support and the pressure bearing surface and the cylinder is ensured to be stable, the uniform loading is carried out at the speed of 0.01-0.015MPa/s, and the damage load and the crack position are recorded. The flexural strength was calculated as follows:
Fs＝Fl/bh2wherein Fs represents flexural strength (MPa); f represents the specimen breaking load, l represents the span between the supports, b represents the specimen section width (mm), and h represents the specimen section height (mm).
3. Sulfate attack test: firstly, preparing a sodium sulfate solution with the mass concentration of 10%, and respectively soaking the concrete test piece in the sodium sulfate solution for 30d, 60d and 90d to test the mass loss rate of the concrete after the corrosion age. The method for testing the mass loss rate comprises the following steps: the initial mass G of the dried test block is weighed by adopting an electron with the precision of 0.01G, the test block dried after being soaked in the sulfate is placed on an electronic balance to weigh the mass G1 of the test block after being corroded by the sulfate, and the mass loss rate is calculated according to the following formula: w ═ G-G1)/G; wherein W represents the mass loss rate (%) of the concrete block.
Figure BDA0002754438660000101
The comparison of the test data recorded in the table shows that the mass loss rate of the concrete after being soaked by sodium sulfate is obviously lower than that of the concrete in the comparative example and the comparative example, and the concrete prepared by the invention has good sulfate corrosion resistance. In addition, the mass loss rate of the concrete is not greatly increased after the concrete is soaked for 60d to 90d by the sodium sulfate, but the mass loss rates of the concrete in the comparative example and the comparative example are greatly increased to different degrees after the concrete is soaked for 60d to 90d, so that the concrete in the examples has the durable sulfate corrosion resistance. In addition, the mechanical properties of the concrete in the embodiment are slightly better than those of the comparative example obtained by comparing the compressive strength and the flexural strength of the concrete in the embodiment with those of the comparative example, and the sulfate-resistant composite particles are proved to be capable of improving the compressive strength and the flexural strength of the concrete to a small extent after being added into the concrete.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution of the present invention and its inventive concept within the technical scope of the present invention.

Claims (9)

1. The sulfate erosion resistant concrete is characterized by comprising the following components in percentage by mass
20-23% of Portland cement, 15-18% of broken stone, 10-15% of natural sand, 8-12% of glass fiber, 5-8% of mineral powder, 5-10% of sulfate-resistant composite particles, 1-3% of polycarboxylic acid water reducing agent and the balance of water.
2. The sulfate attack resistant concrete according to claim 1, wherein the crushed stone has a particle size of 16 to 20 mm.
3. The sulfate attack resistant concrete according to claim 1, wherein the natural sand has a fineness modulus of 2.5 to 3.0.
4. The sulfate attack resistant concrete according to claim 1, wherein the preparation method of the sulfate-resistant composite particles comprises the following steps:
s1, adding an epoxy silane coupling agent into a mixed solution of ethanol and water, adjusting the pH value of the system to 3-5, heating in a water bath to 50-60 ℃, stirring and hydrolyzing to obtain a hydrolysis solution, adding nano-silica into the hydrolysis solution, stirring and reacting for 1-3h, centrifuging, washing and drying to obtain coupling agent modified nano-silica, adding the coupling agent modified nano-silica into a carboxymethyl chitosan aqueous solution, then adding a stannic chloride catalyst, heating to 80-85 ℃, stirring and reacting for 2-5h, centrifuging, washing and drying to obtain surface modified nano-silica;
s2, adding 2-methylimidazole into the methanol solution, stirring and dissolving, then adding the surface modified nano-silica, and stirring and mixing uniformly to obtain a suspension; adding Zn (NO)3)2▪6H2Adding O into a methanol solution, stirring and dissolving to obtain a zinc nitrate solution, dropwise adding the zinc nitrate solution into the suspension, stirring and reacting for 2-5h, centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particles;
s3, adding barium nitrate into deionized water, stirring and dissolving to obtain a barium nitrate solution, adding the metal organic framework nanosheet-silicon dioxide composite particles into the barium nitrate solution, soaking for 15-20h at room temperature, centrifuging, washing and drying to obtain the metal organic framework nanosheet-silicon dioxide composite particles loaded with barium nitrate; adding the barium nitrate-loaded metal organic framework nanosheet-silicon dioxide composite particle into a carboxymethyl cellulose solution, stirring and mixing uniformly, soaking for 5-10h at room temperature, centrifuging, washing and drying to obtain the sulfate-resistant composite particle.
5. The sulfate attack resistant concrete according to claim 4, wherein the mass ratio of the coupling agent modified nano silica to the carboxymethyl chitosan in the step S1 is 1: 0.3-0.8.
6. The sulfate attack resistant concrete according to claim 4, wherein the mass ratio of the 2-methylimidazole to the surface-modified nano-silica in the step S2 is 1: 0.4-0.7.
7. The sulfate attack resistant concrete according to claim 4, wherein the mass concentration of the barium nitrate solution in the step S3 is 0.5-5.0%.
8. The sulfate attack resistant concrete according to claim 4, wherein the mass concentration of the carboxymethyl cellulose solution in step S3 is 2.5-4.0%.
9. A method of producing a sulphate attack resistant concrete according to any one of claims 1 to 8 including the steps of: adding the portland cement, the broken stone and the natural sand into a stirrer, and uniformly stirring and mixing to obtain a premix; adding a polycarboxylate superplasticizer into water, stirring and dissolving to obtain a polycarboxylate superplasticizer solution, adding the polycarboxylate superplasticizer solution into the premix for wet mixing, then adding glass fibers, mineral powder and sulfate-resistant composite particles, and continuously stirring and uniformly mixing to obtain the polycarboxylate superplasticizer.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115180867A (en) * 2022-07-15 2022-10-14 安徽建筑大学 Targeted sulfate corrosion-resistant preservative with spherical shell structure and preparation method and application thereof
CN115259791A (en) * 2022-07-26 2022-11-01 中能建西北城市建设有限公司 Volcanic ash based acid-resistant concrete and preparation method thereof
CN116444244A (en) * 2023-04-18 2023-07-18 宁波万格休闲用品有限公司 Corrosion-resistant umbrella base and preparation method thereof

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115180867A (en) * 2022-07-15 2022-10-14 安徽建筑大学 Targeted sulfate corrosion-resistant preservative with spherical shell structure and preparation method and application thereof
CN115180867B (en) * 2022-07-15 2023-04-11 安徽建筑大学 Targeted sulfate corrosion-resistant preservative with spherical shell structure and preparation method and application thereof
CN115259791A (en) * 2022-07-26 2022-11-01 中能建西北城市建设有限公司 Volcanic ash based acid-resistant concrete and preparation method thereof
CN116444244A (en) * 2023-04-18 2023-07-18 宁波万格休闲用品有限公司 Corrosion-resistant umbrella base and preparation method thereof
CN116444244B (en) * 2023-04-18 2023-11-14 宁波万格休闲用品有限公司 Corrosion-resistant umbrella base and preparation method thereof

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