CN112266213A - High-strength sulfate corrosion-resistant concrete and preparation method thereof - Google Patents

High-strength sulfate corrosion-resistant concrete and preparation method thereof Download PDF

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CN112266213A
CN112266213A CN202011181069.0A CN202011181069A CN112266213A CN 112266213 A CN112266213 A CN 112266213A CN 202011181069 A CN202011181069 A CN 202011181069A CN 112266213 A CN112266213 A CN 112266213A
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concrete
stirring
basalt fiber
resistant concrete
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秦欢欢
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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
    • C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
    • C04B20/02—Treatment
    • C04B20/023—Chemical treatment
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • 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

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  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

The invention relates to the technical field of concrete, and discloses high-strength sulfate corrosion-resistant concrete and a preparation method thereof. Comprises the following components in percentage by mass: 18-22% of Portland cement, 6-10% of modified basalt fiber, 5-8% of silica powder, 15-20% of river sand, 20-25% of granite broken stone, 0.5-1.0% of sodium nitrite antifreezing agent, 1.0-1.5% of polycarboxylic acid retarding water reducing agent and the balance of water. The concrete preparation method is that the polycarboxylic acid retarding water reducer is added into water and stirred to be dissolved to prepare the polycarboxylic acid retarding water reducer aqueous solution; adding portland cement, river sand and granite broken stone into a stirrer, and carrying out dry stirring to obtain a dry stirring material; pouring the polycarboxylic acid retarding and water reducing agent aqueous solution into a dry-mixed material for wet mixing, then adding the modified basalt fiber, the silicon powder and the sodium nitrite, and uniformly stirring to obtain the modified basalt fiber modified concrete. The concrete prepared by the invention has good mechanical property and sulfate corrosion resistance.

Description

High-strength sulfate corrosion-resistant concrete and preparation method thereof
Technical Field
The invention relates to the technical field of concrete, in particular to high-strength sulfate corrosion resistant concrete and a preparation method thereof.
Background
The concrete is a general term for engineering composite materials formed by binding aggregates into a whole by using a binding material, and the term concrete generally refers to cement concrete which is obtained by mixing cement as the binding material and sand and stone as the aggregates with water according to a certain proportion and stirring, and is also called ordinary concrete and widely applied to civil engineering. Under the background of rapid development of modern society, along with the rapid progress of urbanization, the engineering construction of cities is also rapidly developing. Concrete is widely used as a main building material in construction, has been a driving force for the development of buildings and infrastructures in many countries, and the use of concrete is continued for a long time in the future. Concrete buildings or roads in the normal use stage, if in a complex environment, are subject to different physical or chemical attacks, which cause inevitable damages in the concrete, jeopardizing the safety of use and the life. The corrosion of the sulfate environment to concrete is extremely destructive, and the sulfate environment is widely distributed in the building engineering of China, such as saline-alkali soil, salt lake and the like in coastal areas, near coast and northwest areas. The service of concrete in these environments can cause the damage of concrete structures, influence the durability of the concrete structures, accelerate the failure of the concrete structures and cause a great number of potential safety hazards.
Chinese patent publication No. CN107721287 discloses a diatomite modified concrete and a preparation method thereof, comprising cement, diatomite, water, river sand, broken stone and a water reducing agent; for another example, chinese patent publication No. CN103880364 discloses a pervious concrete of industrial waste and a preparation method thereof, which comprises the following components in parts by weight: cement, silica fume, waste stone, fly ash, a water reducing agent and water. Chinese patent publication No. CN111205002 discloses a high-toughness super-sulfate cement and a preparation method thereof, wherein the cement comprises slag, gypsum, an excitant, an admixture, fibers and a coagulation adjusting type water reducing agent. Although the concrete obtained by the technical scheme of the patent has certain mechanical strength, the sulfate corrosion resistance of the concrete is poor, and the application of the cement in special environment is limited.
Disclosure of Invention
The invention provides a high-strength sulfate corrosion-resistant concrete for overcoming the problem of poor sulfate corrosion resistance of concrete in the prior art. The concrete prepared by the invention has good mechanical property and sulfate corrosion resistance.
The invention also provides a preparation method of the high-strength sulfate corrosion-resistant concrete.
In order to achieve the purpose, the invention adopts the following technical scheme: the high-strength sulfate corrosion-resistant concrete comprises the following components in percentage by mass:
18-22% of Portland cement, 6-10% of modified basalt fiber, 5-8% of silica powder, 15-20% of river sand, 20-25% of granite broken stone, 0.5-1.0% of sodium nitrite antifreezing agent, 1.0-1.5% of polycarboxylic acid retarding water reducing agent and the balance of water.
According to the concrete, the Portland cement is used as a main component of the concrete, the river sand is used as a fine aggregate of the concrete, the granite broken stone is used as a coarse aggregate of the concrete, the basalt fiber and the silicon powder are compounded to fill the pores in the concrete, so that the compactness of the concrete is improved, and the preliminary blocking effect on the external sulfate in the concrete is achieved, so that the speed of the external sulfate diffusing into the concrete is reduced, the corrosion effect of the sulfate on the concrete is reduced, and the durability of the concrete is improved; on the other hand, the basalt fibers are fully dispersed in the concrete, so that the framework of the concrete can be enhanced, the mechanical strength of the concrete is improved, and the concrete is not easy to crack in the process of being taken.
Preferably, the particle size of the granite broken stone is 18-20mm, the content of needle-shaped particles is less than or equal to 6%, and the mud content is less than or equal to 0.5%.
Preferably, the fineness modulus of the river sand is 2.4-2.8, and the mud content is less than or equal to 1.8%.
Preferably, the preparation method of the modified basalt fiber comprises the following steps:
adding trimesoyl chloride into a normal hexane solvent, stirring and dissolving to obtain a trimesoyl chloride solution for later use; adding dopamine hydrochloride into deionized water, stirring and dissolving to obtain a dopamine solution, dropwise adding a sodium hydroxide solution and a Tirs-HCl buffer solution into the dopamine solution to adjust the pH value of the dopamine solution to 7-8, adding basalt fibers and a surfactant sodium dodecyl sulfate into the dopamine solution, heating to 40-60 ℃, stirring and reacting for 5-10 hours, filtering and separating the basalt fibers, immediately adding the basalt fibers separated by filtering into a trimesoyl chloride solution, reacting for 20-30 minutes at room temperature, filtering, separating, washing and drying to obtain the modified basalt fibers.
The sulfate erosion of concrete is a slow process, sulfate firstly reacts with calcium hydroxide in the concrete to generate calcium sulfate, the calcium sulfate then reacts with hydrated calcium aluminate in the concrete to form hydrated calcium sulphoaluminate (ettringite), and the ettringite is extremely difficult to dissolveCan be combined with water molecules to cause volume increase and expansion, thereby causing concrete cracking. In the prior art, the adopted method for improving the sulfate corrosion resistance of concrete generally comprises the steps of mixing inorganic particles in the concrete, and filling the inorganic particles in the pores of the concrete, so that the compactness of the concrete is improved, a sulfate solution is prevented from entering the pores inside the concrete from the external environment, and the corrosion effect of sulfate on the concrete is slowed down. However, the prior art has the problem that the complete filling of the internal pores of the concrete is difficult to achieve through the filling effect of the inorganic particles, so that the method is not good for improving the sulfate corrosion resistance of the concrete. In order to solve the problem, the basalt fiber is used as a carrier, a polydopamine layer is polymerized and crosslinked on the surface of the basalt fiber by utilizing the auto-oxidation polymerization of dopamine, then, amino loaded on the dopamine layer reacts with one acyl chloride group in trimesoyl chloride molecules to generate an amide group, so that trimesoyl chloride is grafted to the surface of the basalt fiber, the other two acyl chloride groups in the trimesoyl chloride molecules are hydrolyzed to generate carboxyl, so that the carboxyl is loaded on the surface of the basalt fiber, the volume of the trimesoyl chloride molecules is small, and the two acyl chloride groups are hydrolyzed to generate the carboxyl, so that more carboxyl is loaded on the surface of the basalt fiber. When the concrete is contacted with the sulfate aqueous solution, carboxyl loaded on the surfaces of basalt fibers in the concrete is ionized and negatively charged, and the carboxyl and SO in sulfate are subjected to ionization and negative charge4 2-And electrostatic repulsion exists between anions, so that sulfate is prevented from entering the concrete, the expansion corrosion of the concrete caused by the sulfate entering the concrete is prevented, and the durability of the concrete is improved. On the other hand, the basalt fibers and the silicon powder can be compounded to fill the pores in the concrete, so that the compactness of the concrete is improved, and the corrosion damage of the concrete caused by the sulfate entering the concrete is further prevented.
Preferably, the mass concentration of the trimesoyl chloride solution is 0.3-0.8%.
Preferably, the mass ratio of the basalt fibers to the dopamine hydrochloride is 1: 0.5-1.2.
Preferably, the basalt fibers are pretreated, and the method comprises the following steps:
adding zinc acetate dihydrate into deionized water, stirring and dissolving to prepare a zinc acetate solution for later use; adding oxalic acid into absolute ethyl alcohol, stirring and dissolving to prepare an oxalic acid solution, adding basalt fiber and a triammonium citrate surfactant into the oxalic acid solution, and uniformly mixing by ultrasonic oscillation to obtain a mixed solution; slowly dripping the zinc acetate solution into the mixed solution, reacting for 1-3h at a constant temperature of 70-80 ℃, filtering and separating out basalt fiber, drying in a drying oven, and then delivering into a muffle furnace for high-temperature calcination for 2-5h at a temperature of 500-600 ℃ to obtain the composite material.
In the experimental process, the content of carboxyl loaded on the surface of the basalt fiber in the prepared concrete is low, and the electrostatic repulsion effect of the concrete on external sulfate particles is weak, so that the sulfate corrosion resistance of the concrete is influenced. Experimental research shows that the polydopamine layer covered on the surface of the basalt scale can fall off from the surface of the basalt fiber under the stirring action in the process of a concrete preparation mixing procedure, so that the content of carboxyl loaded on the surface of the basalt fiber is reduced. The preparation method further pretreats the basalt fibers, and utilizes a sol-gel method to deposit and combine nano zinc oxide on the surfaces of the basalt fibers by taking zinc acetate as a precursor, so as to prepare the nano zinc oxide-basalt fiber composite material, wherein the nano zinc oxide increases the roughness of the surfaces of the basalt fibers, so that the combination acting force of the basalt fibers and a polydopamine layer is increased, in addition, the nano zinc oxide is loaded with more hydroxyl groups and forms hydrogen bond acting force with amino groups and other groups loaded on the polydopamine layer, so that the combination acting force of the polydopamine layer and the basalt fibers is further increased, and the phenomenon that the covered polydopamine layer on the surfaces of basalt scales falls off from the surfaces of the basalt fibers in the process of preparing and mixing concrete is avoided.
Preferably, the mass ratio of the zinc acetate dihydrate to the oxalic acid is 1: 1.3-1.6.
Preferably, the mass ratio of the basalt fibers to the oxalic acid is 1:0.5-1.
The preparation method of the high-strength sulfate corrosion-resistant concrete comprises the following steps:
adding a polycarboxylic acid retarding water reducer into water, stirring and dissolving to prepare a polycarboxylic acid retarding water reducer aqueous solution for later use; adding portland cement, river sand and granite broken stone into a stirrer, and performing dry stirring at a stirring speed of 20-30r/min for 5-10min to obtain a dry stirred material; and pouring the polycarboxylic acid retarding and water reducing agent aqueous solution into the dry mixed material, performing wet mixing for 15-30min at a speed of 30-40r/min, adding the modified basalt fiber, the silicon powder and the sodium nitrite, and continuously stirring for 20-35min to obtain the modified basalt fiber modified water reducing agent.
Therefore, the invention has the following beneficial effects: (1) the basalt fibers are dispersed in the concrete, so that the skeleton of the concrete can be enhanced, the mechanical strength of the concrete is improved, and the concrete is not easy to crack in the process of being taken; (2) the carboxyl loaded on the surface of the basalt fiber in the concrete generates ionization and shows negative electricity, and the ionization and the negative electricity are combined with SO in sulfate4 2-The anions have electrostatic repulsion, so that sulfate is prevented from entering the concrete, the expansion corrosion of the concrete caused by the sulfate entering the concrete is prevented, and the durability of the concrete is improved; (3) the basalt fibers and the silicon powder can be compounded to fill the pores in the concrete, so that the compactness of the concrete is improved, and the corrosion damage of the concrete caused by the sulfate entering the concrete is further prevented.
Detailed Description
The technical solution of the present invention is further illustrated by the following specific examples. In the present invention, unless otherwise specified, raw materials, equipment, and the like used are commercially available or commonly used in the art, and the methods in the examples are conventional in the art unless otherwise specified.
The Portland cement used in the specific embodiment is general Portland cement produced by Tangshan Hongyan cement Co Ltd, and the test results of various performance indexes are shown in the following table:
Figure BDA0002750198400000041
in the concrete embodiment, the particle size of the granite broken stone is 18-20mm, the content of needle-shaped particles is less than or equal to 6 percent, and the mud content is less than or equal to 0.5 percent; the fineness modulus of the used river sand is 2.4-2.8, and the mud content is less than or equal to 1.8%.
Example 1
The high-strength sulfate corrosion-resistant concrete comprises the following components in percentage by mass:
20% of Portland cement, 8% of modified basalt fiber, 7% of silica powder, 18% of river sand, 23% of granite broken stone, 0.9% of sodium nitrite antifreezing agent, 1.3% of polycarboxylic acid retarding water reducing agent and the balance of water.
The method for pretreating the basalt fibers comprises the following steps:
adding zinc acetate dihydrate into deionized water according to the mass-volume ratio of 1g/30mL, stirring and dissolving to prepare a zinc acetate solution for later use; adding oxalic acid into absolute ethyl alcohol according to the proportion of 1g/60mL, stirring and dissolving to prepare an oxalic acid solution, wherein the mass ratio of zinc acetate dihydrate to oxalic acid is 1:1.6, adding basalt fiber and ammonium citrate tribasic surfactant into the oxalic acid solution, the mass ratio of the basalt fiber to the oxalic acid is 1:0.9, the addition amount of the ammonium citrate tribasic is 0.5 wt% of the oxalic acid solution, and uniformly mixing by ultrasonic oscillation to obtain a mixed solution; slowly dropwise adding the zinc acetate solution into the mixed solution, reacting for 2.5h at a constant temperature of 70 ℃, filtering and separating out basalt fibers, drying for 2h at 50 ℃ in a drying oven, and then delivering into a muffle furnace to calcine for 2h at a high temperature of 600 ℃ to obtain the composite material.
The preparation method of the modified basalt fiber comprises the following steps:
adding trimesoyl chloride into a normal hexane solvent, stirring and dissolving to obtain a trimesoyl chloride solution with the mass concentration of 0.6% for later use; adding dopamine hydrochloride into deionized water according to the mass-to-volume ratio of 1g/50mL, stirring and dissolving to obtain a dopamine solution, dropwise adding a sodium hydroxide solution and a Tirs-HCl buffer solution into the dopamine solution to adjust the pH value of the dopamine solution to 8, adding pretreated basalt fiber and a surfactant, namely sodium dodecyl sulfate into the dopamine solution, wherein the mass ratio of the basalt fiber to the dopamine hydrochloride is 1:1, the addition amount of the sodium dodecyl sulfate is 0.3 wt% of the dopamine solution, heating to 55 ℃, stirring and reacting for 8 hours, filtering and separating out basalt fiber, immediately adding the basalt fiber separated by filtering into a trimesoyl chloride solution, reacting for 27 minutes at room temperature, filtering, separating, washing and drying to obtain the modified basalt fiber.
The preparation method of the high-strength sulfate corrosion-resistant concrete comprises the following steps:
adding a polycarboxylic acid retarding water reducer into water, stirring and dissolving to prepare a polycarboxylic acid retarding water reducer aqueous solution for later use; adding portland cement, river sand and granite broken stone into a stirrer, and performing dry stirring for 5min at a stirring speed of 30r/min to obtain a dry stirring material; and pouring the polycarboxylic acid retarding and water reducing agent aqueous solution into the dry mixed material, performing wet mixing for 30min at a speed of 30r/min, adding the modified basalt fiber, the silicon powder and the sodium nitrite, and continuously stirring for 30min to obtain the modified basalt fiber modified water reducing agent.
Example 2
The high-strength sulfate corrosion-resistant concrete comprises the following components in percentage by mass:
19% of Portland cement, 7% of modified basalt fiber, 6% of silicon powder, 17% of river sand, 22% of granite broken stone, 0.6% of sodium nitrite antifreezing agent, 1.2% of polycarboxylic acid retarding water reducing agent and the balance of water.
The method for pretreating the basalt fibers comprises the following steps:
adding zinc acetate dihydrate into deionized water according to the mass-volume ratio of 1g/30mL, stirring and dissolving to prepare a zinc acetate solution for later use; adding oxalic acid into absolute ethyl alcohol according to the proportion of 1g/60mL, stirring and dissolving to prepare an oxalic acid solution, wherein the mass ratio of zinc acetate dihydrate to oxalic acid is 1:1.3, adding basalt fiber and ammonium citrate tribasic surfactant into the oxalic acid solution, the mass ratio of the basalt fiber to the oxalic acid is 1:0.6, the addition amount of the ammonium citrate tribasic is 0.5 wt% of the oxalic acid solution, and uniformly mixing by ultrasonic oscillation to obtain a mixed solution; slowly dropwise adding the zinc acetate solution into the mixed solution, reacting at the constant temperature of 80 ℃ for 1.5h, filtering to separate out basalt fibers, drying in a drying oven at 50 ℃ for 2h, and then feeding into a muffle furnace to calcine at the high temperature of 500 ℃ for 5h to obtain the composite material.
The preparation method of the modified basalt fiber comprises the following steps:
adding trimesoyl chloride into a normal hexane solvent, stirring and dissolving to obtain a trimesoyl chloride solution with the mass concentration of 0.4% for later use; adding dopamine hydrochloride into deionized water according to the mass-to-volume ratio of 1g/50mL, stirring and dissolving to obtain a dopamine solution, dropwise adding a sodium hydroxide solution and a Tirs-HCl buffer solution into the dopamine solution to adjust the pH value of the dopamine solution to 7, adding pretreated basalt fiber and a surfactant, namely sodium dodecyl sulfate into the dopamine solution, wherein the mass ratio of the basalt fiber to the dopamine hydrochloride is 1:0.8, the addition amount of the sodium dodecyl sulfate is 0.3 wt% of the dopamine solution, heating to 45 ℃, stirring and reacting for 6 hours, filtering and separating out basalt fiber, immediately adding the basalt fiber separated by filtering into a trimesoyl chloride solution, reacting for 22 minutes at room temperature, filtering, separating, washing and drying to obtain the modified basalt fiber.
The preparation method of the high-strength sulfate corrosion-resistant concrete comprises the following steps:
adding a polycarboxylic acid retarding water reducer into water, stirring and dissolving to prepare a polycarboxylic acid retarding water reducer aqueous solution for later use; adding portland cement, river sand and granite broken stone into a stirrer, and performing dry stirring at a stirring speed of 20r/min for 10min to obtain a dry stirring material; and pouring the polycarboxylic acid retarding and water reducing agent aqueous solution into the dry mixed material, performing wet mixing for 15min at a speed of 40r/min, adding the modified basalt fiber, the silicon powder and the sodium nitrite, and continuously stirring for 25min to obtain the modified basalt fiber modified water reducing agent.
Example 3
The high-strength sulfate corrosion-resistant concrete comprises the following components in percentage by mass:
22% of Portland cement, 10% of modified basalt fiber, 8% of silica powder, 20% of river sand, 25% of granite broken stone, 1.0% of sodium nitrite antifreezing agent, 1.5% of polycarboxylic acid retarding water reducing agent and the balance of water.
The method for pretreating the basalt fibers comprises the following steps:
adding zinc acetate dihydrate into deionized water according to the mass-volume ratio of 1g/30mL, stirring and dissolving to prepare a zinc acetate solution for later use; adding oxalic acid into absolute ethyl alcohol according to the proportion of 1g/60mL, stirring and dissolving to prepare an oxalic acid solution, wherein the mass ratio of zinc acetate dihydrate to oxalic acid is 1:1.5, adding basalt fiber and ammonium citrate tribasic surfactant into the oxalic acid solution, the mass ratio of the basalt fiber to the oxalic acid is 1:1, the addition amount of the ammonium citrate tribasic is 0.5 wt% of the oxalic acid solution, and uniformly mixing by ultrasonic oscillation to obtain a mixed solution; slowly dropwise adding a zinc acetate solution into the mixed solution, carrying out constant-temperature heat preservation reaction for 3h at 75 ℃, filtering and separating out basalt fibers, drying the basalt fibers in a drying oven for 2h at 50 ℃, and then delivering the basalt fibers into a muffle furnace to calcine the basalt fibers for 3h at 550 ℃ to obtain the composite material.
The preparation method of the modified basalt fiber comprises the following steps:
adding trimesoyl chloride into a normal hexane solvent, stirring and dissolving to obtain a trimesoyl chloride solution with the mass concentration of 0.8% for later use; adding dopamine hydrochloride into deionized water according to the mass-to-volume ratio of 1g/50mL, stirring and dissolving to obtain a dopamine solution, dropwise adding a sodium hydroxide solution and a Tirs-HCl buffer solution into the dopamine solution to adjust the pH value of the dopamine solution to 7.5, adding pretreated basalt fiber and a surfactant lauryl sodium sulfate into the dopamine solution, wherein the mass ratio of the basalt fiber to the dopamine hydrochloride is 1:1.2, the addition amount of the lauryl sodium sulfate is 0.3 wt% of the dopamine solution, heating to 60 ℃, stirring and reacting for 10 hours, filtering and separating out basalt fiber, immediately adding the basalt fiber separated by filtering into a trimesoyl chloride solution, reacting for 30 minutes at room temperature, filtering, separating, washing and drying to obtain the modified basalt fiber.
The preparation method of the high-strength sulfate corrosion-resistant concrete comprises the following steps:
adding a polycarboxylic acid retarding water reducer into water, stirring and dissolving to prepare a polycarboxylic acid retarding water reducer aqueous solution for later use; adding portland cement, river sand and granite crushed stone into a stirrer, and carrying out dry stirring for 8min at a stirring speed of 25r/min to obtain a dry stirring material; and pouring the polycarboxylic acid retarding and water reducing agent aqueous solution into the dry mixed material, performing wet mixing for 20min at the speed of 35r/min, adding the modified basalt fiber, the silicon powder and the sodium nitrite, and continuously stirring for 35min to obtain the modified basalt fiber modified water reducing agent.
Example 4
The high-strength sulfate corrosion-resistant concrete comprises the following components in percentage by mass:
18% of Portland cement, 6% of modified basalt fiber, 5% of silica powder, 15% of river sand, 20% of granite broken stone, 0.5% of sodium nitrite antifreezing agent, 1.0% of polycarboxylic acid retarding water reducing agent and the balance of water.
The method for pretreating the basalt fibers comprises the following steps:
adding zinc acetate dihydrate into deionized water according to the mass-volume ratio of 1g/30mL, stirring and dissolving to prepare a zinc acetate solution for later use; adding oxalic acid into absolute ethyl alcohol according to the proportion of 1g/60mL, stirring and dissolving to prepare an oxalic acid solution, wherein the mass ratio of zinc acetate dihydrate to oxalic acid is 1:1.5, adding basalt fiber and ammonium citrate tribasic surfactant into the oxalic acid solution, the mass ratio of the basalt fiber to the oxalic acid is 1:0.5, the addition amount of the ammonium citrate tribasic is 0.5 wt% of the oxalic acid solution, and uniformly mixing by ultrasonic oscillation to obtain a mixed solution; slowly dropwise adding a zinc acetate solution into the mixed solution, carrying out constant-temperature heat preservation reaction for 1h at 75 ℃, filtering and separating out basalt fibers, drying the basalt fibers in a drying oven for 2h at 50 ℃, and then delivering the basalt fibers into a muffle furnace to calcine the basalt fibers for 3h at 550 ℃ to obtain the composite material.
The preparation method of the modified basalt fiber comprises the following steps:
adding trimesoyl chloride into a normal hexane solvent, stirring and dissolving to obtain a trimesoyl chloride solution with the mass concentration of 0.3% for later use; adding dopamine hydrochloride into deionized water according to the mass-to-volume ratio of 1g/50mL, stirring and dissolving to obtain a dopamine solution, dropwise adding a sodium hydroxide solution and a Tirs-HCl buffer solution into the dopamine solution to adjust the pH value of the dopamine solution to 7.5, adding pretreated basalt fiber and a surfactant lauryl sodium sulfate into the dopamine solution, wherein the mass ratio of the basalt fiber to the dopamine hydrochloride is 1:0.5, the addition amount of the lauryl sodium sulfate is 0.3 wt% of the dopamine solution, heating to 40 ℃, stirring and reacting for 5 hours, filtering and separating out basalt fiber, immediately adding the basalt fiber separated by filtering into a trimesoyl chloride solution, reacting for 20 minutes at room temperature, filtering, separating, washing and drying to obtain the modified basalt fiber.
The preparation method of the high-strength sulfate corrosion-resistant concrete comprises the following steps:
adding a polycarboxylic acid retarding water reducer into water, stirring and dissolving to prepare a polycarboxylic acid retarding water reducer aqueous solution for later use; adding portland cement, river sand and granite crushed stone into a stirrer, and carrying out dry stirring for 8min at a stirring speed of 25r/min to obtain a dry stirring material; and pouring the polycarboxylic acid retarding and water reducing agent aqueous solution into the dry mixed material, performing wet mixing for 20min at the speed of 35r/min, adding the modified basalt fiber, the silicon powder and the sodium nitrite, and continuously stirring for 20min to obtain the modified basalt fiber modified water reducing agent.
Comparative example 1
Comparative example 1 is different from example 1 in that the modified basalt fiber is replaced with a general basalt fiber.
Comparative example 2
Comparative example 2 is different from example 1 in that basalt fiber is not pretreated.
Testing of concrete Properties
1. And (3) testing the compressive strength: preparing a concrete standard cube test block with the size of 100mm multiplied by 100mm, maintaining the test block for 7d, placing the test block at the position between an upper pressure plate and a lower pressure plate of a pressure tester, starting the pressure tester, uniformly controlling the loading of the pressure machine by a computer, and controlling the speed at 0.8 MPa/s; calculating the tensile strength of the sample according to the formula F ═ F/A; wherein F represents the compressive strength (MPa) of the concrete sample block, F represents the load (N) when the sample block is broken under pressure, and A is the bearing area (mm) of the bottom surface of the sample block2) The results are shown in Table 1.
2. Splitting tensile strength test: preparing a concrete standard cube test block with the size of 100mm multiplied by 100mm, maintaining the test block for 7d, placing the test block in a split-pulling test mould, placing the mould with the test block in the middle position of an upper pressing plate and a lower pressing plate of a pressure tester, starting the tester, uniformly controlling the loading of the pressure tester by a computer, and controlling the speed at 0.08 MPa/s. The split tensile compressive strength of the concrete sample block was calculated according to the following formula: f. ofts2F/pi a; wherein f istsSplit tensile representing concrete sample blockStrength (MPa), F is the load (N) at the time of pressure failure, and A is the area (mm) of the cleavage plane of the test piece2) The results are shown in Table 1.
3. The sizes of the test sample blocks for the sulfate erosion test are standard cubic test blocks of 100mm multiplied by 100mm, each test sample is demoulded after being formed for 24h, and then the test samples are cultured for 28 days under standard conditions (the temperature is 22 +/-2 ℃, and the humidity is 95 +/-3%). The sulfate corrosion test adopts 5% sodium sulfate aqueous solution with mass concentration, and before the sulfate corrosion test is started, the cured 28d test block is placed for 1 day under the laboratory condition of 22 ℃ and 70% relative humidity, so that the excessive moisture is eliminated, and the error is reduced. The corrosion time of the sodium sulfate is controlled to be 120d, the corrosion mode is continuous immersion corrosion, and the solution is replaced every 30 d. The mass change before and after the corrosion of the sodium sulfate is represented by a mass corrosion coefficient, and the mass corrosion coefficient testing method comprises the following steps: the sample was taken out of the sodium sulfate solution and the sample piece was air-dried in an environment at a temperature of 22 ℃ and a relative humidity of 70% until the mass of the sample piece was constant. The brush was then used to remove debris from the surface of the coupon, and the balance was then used to measure the mass of the coupon. The corrosion coefficient of concrete is calculated according to the following formula:
Km＝(M0-M1)/M0x is 100%; where Km represents the corrosion coefficient (%), M0Represents the mass of the sample block before the attack by the sodium sulfate solution, M1The mass of the coupon prior to attack by the sodium sulfate solution is represented and the results are shown in Table 1.
Table 1:
Figure BDA0002750198400000081
the test results show that the corrosion coefficients of the concrete samples of the examples 1-4 are obviously lower than those of the comparative example 1 and the comparative example 2, and the compressive strength of the concrete of the example after 120d corrosion is higher than that of the concrete of the comparative example 1 and the comparative example 2. The basalt fiber is proved to be capable of obviously improving the sulfate corrosion resistance of the concrete through modification treatment and pretreatment.
EXAMPLES the sulfate corrosion resistance of the concrete is due to comparative example 1, which is due to the basalt treated with the inventionAfter the fiber is modified, carboxyl loaded on the surface of the basalt fiber in the concrete is ionized and negatively charged, and the ionized and negatively charged carboxyl and SO in sulfate4 2-And electrostatic repulsion exists between anions, so that sulfate is prevented from entering the concrete, expansion corrosion of the concrete caused by the sulfate entering the concrete is prevented, and the sulfate corrosion resistance of the concrete is improved.
The concrete sulfate corrosion resistance performance of the embodiment is compared with that of the concrete sulfate corrosion resistance performance of the embodiment 2, because the invention pretreats basalt fibers, zinc acetate is used as a precursor by utilizing a sol-gel method, and nano zinc oxide is deposited and combined on the surfaces of the basalt fibers to prepare the nano zinc oxide-basalt fiber composite material, the nano zinc oxide increases the roughness of the surfaces of the basalt fibers, so that the combination acting force of the basalt fibers and a polydopamine layer is increased, the polydopamine layer covered on the surfaces of basalt flakes is prevented from falling off from the surfaces of the basalt fibers in the concrete preparation mixing process, and the carboxyl content of the surfaces of the basalt fibers and the electrostatic repulsion effect on sulfate are further maintained.

Claims (10)

1. The high-strength sulfate corrosion-resistant concrete is characterized by comprising the following components in percentage by mass:
18-22% of Portland cement, 6-10% of modified basalt fiber, 5-8% of silica powder, 15-20% of river sand, 20-25% of granite broken stone, 0.5-1.0% of sodium nitrite antifreezing agent, 1.0-1.5% of polycarboxylic acid retarding water reducing agent and the balance of water.
2. The high-strength sulfate corrosion resistant concrete according to claim 1, wherein the granite broken stone has a particle size of 18-20mm, a content of needle-like particles of 6% or less, and a content of mud of 0.5% or less.
3. The high-strength sulfate corrosion resistant concrete according to claim 1, wherein the fineness modulus of the river sand is 2.4-2.8, and the mud content is less than or equal to 1.8%.
4. The high-strength sulfate corrosion resistant concrete according to claim 1, wherein the preparation method of the modified basalt fiber comprises the following steps:
adding trimesoyl chloride into a normal hexane solvent, stirring and dissolving to obtain a trimesoyl chloride solution for later use; adding dopamine hydrochloride into deionized water, stirring and dissolving to obtain a dopamine solution, dropwise adding a sodium hydroxide solution and a Tirs-HCl buffer solution into the dopamine solution to adjust the pH value of the dopamine solution to 7-8, adding basalt fibers and a surfactant sodium dodecyl sulfate into the dopamine solution, heating to 40-60 ℃, stirring and reacting for 5-10 hours, filtering and separating the basalt fibers, immediately adding the basalt fibers separated by filtering into a trimesoyl chloride solution, reacting for 20-30 minutes at room temperature, filtering, separating, washing and drying to obtain the modified basalt fibers.
5. The high-strength sulfate corrosion resistant concrete according to claim 4, wherein the mass concentration of the trimesoyl chloride solution is 0.3-0.8%.
6. The high-strength sulfate corrosion resistant concrete according to claim 4, wherein the mass ratio of the basalt fibers to the dopamine hydrochloride is 1: 0.5-1.2.
7. The high-strength sulfate corrosion resistant concrete according to claim 4, wherein the basalt fiber is pretreated, comprising the following steps:
adding zinc acetate dihydrate into deionized water, stirring and dissolving to prepare a zinc acetate solution for later use; adding oxalic acid into absolute ethyl alcohol, stirring and dissolving to prepare an oxalic acid solution, adding basalt fiber and a triammonium citrate surfactant into the oxalic acid solution, and uniformly mixing by ultrasonic oscillation to obtain a mixed solution; slowly dripping the zinc acetate solution into the mixed solution, reacting for 1-3h at a constant temperature of 70-80 ℃, filtering and separating out basalt fiber, drying in a drying oven, and then delivering into a muffle furnace for high-temperature calcination for 2-5h at a temperature of 500-600 ℃ to obtain the composite material.
8. The high-strength sulfate corrosion resistant concrete according to claim 7, wherein the mass ratio of the zinc acetate dihydrate to the oxalic acid is 1: 1.3-1.6.
9. The high-strength sulfate corrosion resistant concrete according to claim 7, wherein the mass ratio of the basalt fiber to the oxalic acid is 1:0.5-1.
10. A method for producing a high-strength sulfate-corrosion-resistant concrete according to any one of claims 1 to 9, comprising the steps of:
adding a polycarboxylic acid retarding water reducer into water, stirring and dissolving to prepare a polycarboxylic acid retarding water reducer aqueous solution for later use; adding portland cement, river sand and granite broken stone into a stirrer, and performing dry stirring at a stirring speed of 20-30r/min for 5-10min to obtain a dry stirred material; and pouring the polycarboxylic acid retarding and water reducing agent aqueous solution into the dry mixed material, performing wet mixing for 15-30min at a speed of 30-40r/min, adding the modified basalt fiber, the silicon powder and the sodium nitrite, and continuously stirring for 20-35min to obtain the modified basalt fiber modified water reducing agent.
CN202011181069.0A 2020-10-29 2020-10-29 High-strength sulfate corrosion-resistant concrete and preparation method thereof Withdrawn CN112266213A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113461377A (en) * 2021-08-12 2021-10-01 四川华构住宅工业有限公司 Acid corrosion resistant concrete and preparation method and application thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113461377A (en) * 2021-08-12 2021-10-01 四川华构住宅工业有限公司 Acid corrosion resistant concrete and preparation method and application thereof

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