CN114890751A - High-durability marine concrete doped with modified silica sol and preparation method thereof - Google Patents
High-durability marine concrete doped with modified silica sol and preparation method thereof Download PDFInfo
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- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical class O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 title claims abstract description 137
- 239000004567 concrete Substances 0.000 title claims abstract description 48
- 238000002360 preparation method Methods 0.000 title claims abstract description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 78
- 239000012615 aggregate Substances 0.000 claims abstract description 37
- 239000006087 Silane Coupling Agent Substances 0.000 claims abstract description 34
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 31
- 239000004568 cement Substances 0.000 claims abstract description 30
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 26
- 239000011707 mineral Substances 0.000 claims abstract description 26
- 238000010992 reflux Methods 0.000 claims abstract description 25
- 238000002156 mixing Methods 0.000 claims abstract description 18
- 239000011259 mixed solution Substances 0.000 claims abstract description 17
- 239000000203 mixture Substances 0.000 claims abstract description 17
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 16
- 238000009833 condensation Methods 0.000 claims abstract description 15
- 230000005494 condensation Effects 0.000 claims abstract description 15
- 238000005303 weighing Methods 0.000 claims abstract description 15
- 239000006184 cosolvent Substances 0.000 claims abstract description 13
- 239000002994 raw material Substances 0.000 claims abstract description 12
- 239000000243 solution Substances 0.000 claims abstract description 12
- 238000003756 stirring Methods 0.000 claims abstract description 9
- 239000008367 deionised water Substances 0.000 claims abstract description 8
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 8
- 238000006243 chemical reaction Methods 0.000 claims abstract description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 36
- 238000000034 method Methods 0.000 claims description 18
- 125000000524 functional group Chemical group 0.000 claims description 10
- 239000011398 Portland cement Substances 0.000 claims description 9
- 238000001816 cooling Methods 0.000 claims description 7
- 239000002253 acid Substances 0.000 claims description 5
- 239000010881 fly ash Substances 0.000 claims description 5
- 239000004570 mortar (masonry) Substances 0.000 claims description 5
- 238000000465 moulding Methods 0.000 claims description 5
- 239000002893 slag Substances 0.000 claims description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 abstract description 14
- 229910001294 Reinforcing steel Inorganic materials 0.000 abstract description 7
- 230000007797 corrosion Effects 0.000 abstract description 7
- 238000005260 corrosion Methods 0.000 abstract description 7
- 239000006185 dispersion Substances 0.000 abstract description 7
- 238000005054 agglomeration Methods 0.000 abstract description 4
- 230000002776 aggregation Effects 0.000 abstract description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 2
- 230000000694 effects Effects 0.000 description 14
- 238000012360 testing method Methods 0.000 description 14
- 239000000377 silicon dioxide Substances 0.000 description 9
- 230000004048 modification Effects 0.000 description 8
- 238000012986 modification Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 230000003628 erosive effect Effects 0.000 description 6
- 238000011049 filling Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000011575 calcium Substances 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 230000036571 hydration Effects 0.000 description 4
- 238000006703 hydration reaction Methods 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 239000005543 nano-size silicon particle Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 235000012239 silicon dioxide Nutrition 0.000 description 4
- 239000002956 ash Substances 0.000 description 3
- 230000035515 penetration Effects 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 239000013535 sea water Substances 0.000 description 3
- 238000006467 substitution reaction Methods 0.000 description 3
- 238000009210 therapy by ultrasound Methods 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 238000001000 micrograph Methods 0.000 description 2
- 239000002105 nanoparticle Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 102000020897 Formins Human genes 0.000 description 1
- 108091022623 Formins Proteins 0.000 description 1
- 238000004566 IR spectroscopy Methods 0.000 description 1
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 1
- 229910018557 Si O Inorganic materials 0.000 description 1
- 229910008051 Si-OH Inorganic materials 0.000 description 1
- 229910006358 Si—OH Inorganic materials 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 230000001476 alcoholic effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- 229910052918 calcium silicate Inorganic materials 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000011083 cement mortar Substances 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- HOOWDPSAHIOHCC-UHFFFAOYSA-N dialuminum tricalcium oxygen(2-) Chemical compound [O--].[O--].[O--].[O--].[O--].[O--].[Al+3].[Al+3].[Ca++].[Ca++].[Ca++] HOOWDPSAHIOHCC-UHFFFAOYSA-N 0.000 description 1
- 239000002612 dispersion medium Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005189 flocculation Methods 0.000 description 1
- 230000016615 flocculation Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 239000011372 high-strength concrete Substances 0.000 description 1
- 238000002329 infrared spectrum Methods 0.000 description 1
- 229910001425 magnesium ion Inorganic materials 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 230000003335 steric effect Effects 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
Images
Classifications
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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
- C04B2111/00008—Obtaining or using nanotechnology related materials
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- 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
- C04B2111/24—Sea water resistance
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Abstract
The invention belongs to the technical field of marine concrete production, and particularly relates to high-durability marine concrete doped with modified silica sol and a preparation method thereof. Respectively weighing a proper amount of silane coupling agent and silica sol, putting the silane coupling agent and the silica sol into a cosolvent consisting of a mixed solution of deionized water and ethanol, uniformly mixing, putting the mixture into a condensation reflux device, and collecting the solution after reaction to obtain modified silica sol; (2) adding the silica sol into water, uniformly stirring to obtain modified silica sol, and uniformly mixing the modified silica sol with the rest raw materials of cement, water, aggregate, mineral admixture and water reducer; (3) and (3) putting the mixture obtained in the step (2) into a mould for forming and maintaining. The modified silica sol capable of solving the problems of uneven dispersion and easy agglomeration of nano-silica particles is added into the concrete, so that the prepared concrete effectively slows down the permeation of chloride ions and the corrosion of the chloride ions to reinforcing steel bars, and the durability of the concrete is improved.
Description
Technical Field
The invention belongs to the technical field of marine concrete production, and particularly relates to high-durability marine concrete doped with modified silica sol and a preparation method thereof.
Background
Due to the complexity of the seawater environment, the problem of durability of concrete in the seawater environment has been the focus of research. The porous structure of the concrete enables corrosive ions in seawater to easily penetrate into the concrete, wherein chloride ions can corrode a reinforcing steel bar to cause corrosion and expansion of the reinforcing steel bar, so that the concrete at the joint of the reinforcing steel bar is easy to crack, a concrete member or a building is broken and damaged under the long-term action of external force or external environment, and the service life of the concrete building is shortened; penetration of sulfate and magnesium ions into the concrete interior produces expansive hydration products (AFt or mg (oh) 2 ) Thereby causing the concrete to expand and crack and reducing the durability of the concrete.
In recent years, nanotechnology is developed rapidly, and nano materials are widely applied, wherein nano silicon dioxide has the advantages of pozzolanic activity, crystal nucleus effect, filling effect and the like, so that extra hydrated calcium silicate (C-S-H) can be generated through reaction with calcium hydroxide, hydration is accelerated by using a nucleation site as a hydration product, pores of concrete can be filled in a nano scale, and the strength of a cement-based material and the compactness of the compact concrete are improved. However, a large number of hydroxyl groups exist on the surface of the nano silicon dioxide, the nano silicon dioxide is easy to agglomerate and adsorb water molecules to influence the slurry fluidity of the cement-based material. Although the nano-silica particles in the silica sol are in a monodispersed state, they are easily mixed with Ca (OH) in a cement environment 2 Polymerization occurs, also affecting the dispersion of the nanoparticles. Therefore, the silica sol is modified to improve the dispersibility of the silica sol in a cement concrete environment.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides high-durability marine concrete doped with modified silica sol and a preparation method thereof. The concrete is doped with the modified silica sol which can solve the problems of uneven dispersion and easy agglomeration of nano silica particles, the prepared concrete has higher density and strength and lower porosity (between 10 and 12 percent), and simultaneously can effectively slow down the permeation of chloride ions and the corrosion of the chloride ions to reinforcing steel bars and improve the durability of the concrete.
On one hand, the invention provides a preparation method of high-durability marine concrete doped with modified silica sol, which comprises the following steps:
(1) preparing modified silica sol: respectively weighing a proper amount of silane coupling agent and silica sol, putting the silane coupling agent and the silica sol into a cosolvent consisting of a mixed solution of deionized water and ethanol, uniformly mixing, putting the mixture into a condensation reflux device, and cooling and collecting the solution after reaction after condensation reflux to obtain modified silica sol;
(2) weighing the following raw materials according to a formula: cement, water, aggregate, mineral admixture, water reducing agent and modified silica sol; adding the modified silica sol into water, and uniformly stirring to obtain a mixed solution, and uniformly mixing the mixed solution with the remaining raw materials of cement, water, aggregate, mineral admixture and water reducer;
(3) and (3) putting the mixture obtained in the step (2) into a mould for forming and maintaining.
In a further improvement of the scheme, the type of the silane coupling agent in the step (1) is KH550, KH560 or KH 570; the ratio of the silane coupling agent to the silica sol is 1:3-1: 5; the ultrasonic time for mixing evenly is 20-30 min; the condensing reflux temperature is 40-70 deg.C, pH is 2-9, and the condensing reflux time is 5-8 h.
The further improvement of this scheme, its characterized in that: the raw materials in the step (2) consist of the following components in parts by weight: portland cement: 400-600 parts of water: 140-210 parts of aggregate: 1200 plus 1800 portions, mineral admixture: 25-35 parts of a water reducing agent: 4-8 parts.
According to the further improvement of the scheme, the aggregate in the step (2) comprises 10-20 parts by weight of 0.075-0.15mm aggregate, 60-80 parts by weight of 1.18-2.36mm aggregate and 160-180 parts by weight of 9.5-16mm aggregate.
In the further improvement of the scheme, the mineral admixture in the step (2) comprises 40 parts of fly ash and 60 parts of slag by weight.
The scheme is further improved, the water reducing agent in the step (2) is a polycarboxylic acid water reducing agent, and the water reducing rate is 14-16%.
The scheme is further improved, the silica sol in the step (2) is added into water and stirred evenly for 3-5 min.
The scheme is further improved, the pH value of the modified silica sol in the step (2) is 9-10, the adding proportion of the modified silica sol is 10-20 parts by weight, the content of nano silica particles in the modified silica sol is 30% -50%, and the grafting rate of organic functional groups on the surfaces of the nano silica particles in the modified silica sol is 10% -40%.
The scheme is further improved, and the preparation method of the high-durability marine concrete doped with the modified silica sol comprises the following steps:
(1) preparing modified silica sol: respectively weighing a proper amount of silane coupling agent and silica sol in a beaker, preparing a mixed solution of deionized water and ethanol with a volume ratio of 1:1 as a cosolvent for later use, mixing the silane coupling agent, the silica sol and the cosolvent, carrying out ultrasonic mixing uniformly, putting the mixture into a flask of a condensation reflux device, adjusting the temperature and the pH, carrying out condensation reflux for a period of time, cooling and collecting the reacted solution, and thus obtaining the modified silica sol;
(2) weighing the following raw materials according to a formula: adding cement, water, aggregate, mineral admixture, water reducing agent and modified silica sol into water, and uniformly stirring to obtain a mixed solution A of the modified silica sol and the water;
pouring the weighed cement, aggregate, mineral admixture, water reducer and mixed liquor A into a planetary mortar stirrer to be stirred uniformly.
(3) And (3) putting the mixture obtained in the step (2) into a mold for molding, and putting the mold into a standard curing room for curing for 28 days with the mold.
In another aspect, the present invention provides a concrete obtained by the above-mentioned method.
The high sulfate resistant portland cement is the cementitious material used in the present invention. The tricalcium aluminate content (less than 3 wt%) in the cement is strictly controlled, so that the formation of gypsum and AFt can be reduced to the maximum extent, and the corrosion of sulfate to concrete is reduced. The mineral admixture replaces part of cement, can reduce hydration heat, has certain activity and improves the performance of concrete. The aggregate is used as a filling material, so that the cement paste has higher volume stability and better durability. The water reducing agent can destroy the flocculation structure of cement particles, play a role in dispersing the cement particles and improve the fluidity of concrete mixtures. The modified silica sol is modified on the basis of common silica sol, so that organic functional groups are grafted on the surface of the silica sol, and the steric hindrance is increased, so that the dispersibility of nano silica particles is improved, and the modified silica sol can better play the crystal nucleus, volcanic ash and filling effect in cement concrete, thereby improving the strength and density of the cement concrete and slowing down the penetration of erosive ions.
The surface of the existing nano-silica contains a large amount of hydrophilic hydroxyl, so that the existing nano-silica is easy to form an agglomerate rather than exist in a monodispersed state, and the nano-silica has certain influence on the dispersion of the nano-silica in a cement-based material, so that the crystal nucleus effect, the volcanic ash effect and the filling effect of the nano-silica cannot be well exerted. The synthesis of silica sol is to solve the problem of agglomeration of nano silica particles, and can be regarded as an aqueous solution in which nano silica particles are uniformly dispersed in water. The internal molecular structure of the silica sol is a network structure of Si-O tetrahedron, and Si-OH exists on the surface and can be combined with H in a dispersion medium + Or OH - So that the surface of the silica sol is charged with the same charges, and the effect of monodispersing the particles is realized by the principle that like charges repel each other. However, the use of silica sols in cement-based materials presents a problem: a large amount of hydroxyl on the surface of the silica sol is easy to react with Ca in a cement pore solution 2+ The combination forms agglomerates resulting in poor dispersion of the silica sol in the cementitious material. For the reasons, the surface modification is carried out on the silica sol, and the steric hindrance is increased by grafting the organic functional group to the surface of the nano-silica in the silica sol, so that the alcoholic hydroxyl and Ca on the surface of the nano-silica are reduced 2+ Improving the agglomeration of the nano-particlesThe dispersion of the silica particles and the selection of proper organic functional groups can enable the surface of the nano silica to have certain hydrophobicity, thereby reducing the water permeability, reducing the corrosion of reinforcing steel bars and improving the durability of concrete.
The silane coupling agent is grafted to the surface of the nano silica particles by a chemical combination mode (different grafting rates), so that the nano silica particles are not easy to react with Ca (OH) when being added into concrete 2 The polymerization occurs, so that three major advantages of the nano silicon dioxide particles can be exerted.
The invention has the beneficial effects that:
(1) according to the invention, silica sol is modified, and the amount of organic functional groups on the surface is controlled, so that nano silica particles in the silica sol can be well dispersed in a cement environment, and the crystal nucleus effect, the volcanic ash effect and the filling effect of the nano silica particles are fully exerted.
(2) According to the invention, silica sol is modified, and the hydrophobicity of the organic functional group grafted on the surface can be utilized to reduce water permeability, reduce corrosion of reinforcing steel bars and improve the durability of marine concrete.
(3) The preparation method of the modified silica sol has the advantages of simple operation and controllable grafting rate, and the organic functional group is bonded on the surface of the silica sol through a chemical bond, so that the bonding is firm, the organic functional group can not fall off due to external factors, and the steric effect of the organic functional group and the dispersibility of the silica sol are better ensured.
Drawings
In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
FIG. 1 is a transmission electron microscope image of the present invention, wherein the left side is silica sol and the right side is modified silica sol.
FIG. 2 is an infrared spectrum of the silica sol and the modified silica sol of the present invention.
FIG. 3 shows (a) flexural strength and (b) compressive strength of the test pieces of the present invention maintained for 3 days, 7 days and 28 days.
Fig. 4 is the porosity change (pore distribution) of the present invention.
FIG. 5 is the change in porosity (cumulative porosity) of the present invention.
FIG. 6 is a photograph of a sample of the chloride ion erosion resistance of the present invention.
FIG. 7 is the chloride ion erosion resistance of the present invention: the upper line represents the chloride ion mobility coefficient and the lower line represents the chloride ion penetration depth.
Detailed Description
In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1:
(1) preparing modified silica sol: respectively weighing a proper amount of silane coupling agent and silica sol in a beaker, preparing a mixed solution of deionized water and ethanol with a volume ratio of 1:1 as a cosolvent for later use, mixing the silane coupling agent, the silica sol and the cosolvent, carrying out ultrasonic mixing uniformly, putting the mixture into a flask of a condensation reflux device, adjusting the temperature and the pH, carrying out condensation reflux for a period of time, cooling and collecting the reacted solution, and thus obtaining the modified silica sol; step 1, the type of the silane coupling agent is KH 560; the ratio of the silane coupling agent to the silica sol is 1: 4; the ultrasonic treatment time is 25 min; the condensing reflux temperature is 50 ℃, the pH value is 7, and the condensing reflux time is 7 h.
(2) Weighing the following raw materials according to a formula: cement, water, aggregate, mineral admixture, water reducing agent, modified silica sol and portland cement, wherein the weight ratio of 500 parts of portland cement to water: 190 parts, aggregate: 1500 parts, mineral admixture: 30 parts of water reducing agent: 6 parts of modified silica sol, and the adding proportion of the modified silica sol is 15 parts. The aggregate comprises 15 parts of 0.075-0.15mm aggregate, 70 parts of 1.18-2.36mm aggregate and 170 parts of 9.5-16mm aggregate in proportion by weight.
The mineral admixture comprises 40 parts of fly ash and 60 parts of slag by weight.
The water reducing agent is a polycarboxylic acid water reducing agent, and the water reducing rate is 14-16%.
The pH value of the modified silica sol in the step (2) is 10, and the content of nano silica particles in the modified silica sol is 40%.
Firstly, adding modified silica sol into water, and stirring uniformly for 3-5min to obtain a mixed solution A of the modified silica sol and the water;
pouring the weighed cement, aggregate, mineral admixture, water reducer and mixed liquor A into a planetary mortar stirrer to be stirred uniformly.
(3) And (3) putting the mixture obtained in the step (2) into a mold for molding, and putting the mold into a standard curing room for curing for 28 days with the mold.
Example 2:
(1) preparing modified silica sol: respectively weighing a proper amount of silane coupling agent and silica sol in a beaker, preparing a mixed solution of deionized water and ethanol with a volume ratio of 1:1 as a cosolvent for later use, mixing the silane coupling agent, the silica sol and the cosolvent, carrying out ultrasonic mixing uniformly, putting the mixture into a flask of a condensation reflux device, adjusting the temperature and the pH, carrying out condensation reflux for a period of time, cooling and collecting the reacted solution, and thus obtaining the modified silica sol; the type of the silane coupling agent in the step 1 is KH 550; the ratio of the silane coupling agent to the silica sol is 1: 3; the ultrasonic treatment time is 20 min; the condensing reflux temperature is 40 ℃, the pH value is 2, and the condensing reflux time is 5 h.
(2) Weighing the following raw materials according to a formula: cement, water, aggregate, mineral admixture, water reducing agent, modified silica sol and portland cement, wherein the weight ratio of portland cement is 40 parts, and water: 140 parts, aggregate: 1200 parts of mineral admixture: 25 parts of water reducing agent: 4 parts of modified silica sol, and the adding proportion of the modified silica sol is 10 parts. The modified silica sol is added in 10 weight portions, and the aggregate includes aggregate in 10 weight portions of 0.075-0.15mm, aggregate in 1.18-2.36mm and aggregate in 9.5-16 mm.
The mineral admixture comprises 40 parts of fly ash and 60 parts of slag by weight.
The water reducing agent is a polycarboxylic acid water reducing agent, and the water reducing rate is 14-16%.
The pH value of the modified silica sol in the step (2) is 9, and the content of nano silica particles in the modified silica sol is 30%.
Firstly, adding modified silica sol into water, and stirring uniformly for 3-5min to obtain a mixed solution A of the modified silica sol and the water;
pouring the weighed cement, aggregate, mineral admixture, water reducer and mixed liquor A into a planetary mortar stirrer to be stirred uniformly.
(3) And (3) putting the mixture obtained in the step (2) into a mold for molding, and putting the mold into a standard curing room for curing for 28 days with the mold.
Example 3:
(1) preparing modified silica sol: respectively weighing a proper amount of silane coupling agent and silica sol in a beaker, preparing a mixed solution of deionized water and ethanol with a volume ratio of 1:1 as a cosolvent for later use, mixing the silane coupling agent, the silica sol and the cosolvent, carrying out ultrasonic mixing uniformly, putting the mixture into a flask of a condensation reflux device, adjusting the temperature and the pH, carrying out condensation reflux for a period of time, cooling and collecting the reacted solution, and thus obtaining the modified silica sol; the type of the silane coupling agent in the step 1 is KH 570; the ratio of the silane coupling agent to the silica sol is 1: 5; the ultrasonic treatment time is 30 min; the condensing reflux temperature is 70 ℃, the pH value is 9, and the condensing reflux time is 8 h.
(2) Weighing the following raw materials according to a formula: cement, water, aggregate, mineral admixture, water reducing agent, modified silica sol and portland cement, wherein 600 parts of portland cement, water: 210 parts of aggregate: 1800 parts of mineral admixture: 35 parts of water reducing agent: 8 parts of modified silica sol, and the adding proportion of the modified silica sol is 20 parts. The addition proportion of the modified silica sol is 20 parts, and the aggregate comprises 20 parts of 0.075-0.15mm aggregate, 80 parts of 1.18-2.36mm aggregate and 180 parts of 9.5-16mm aggregate in aggregate grading according to parts by weight.
The mineral admixture comprises 40 parts of fly ash and 60 parts of slag by weight.
The water reducing agent is a polycarboxylic acid water reducing agent, and the water reducing rate is 14-16%.
The pH value of the modified silica sol in the step (2) is 10, and the content of nano silica particles in the modified silica sol is 50%.
Firstly, adding modified silica sol into water, and stirring uniformly for 3-5min to obtain a mixed solution A of the modified silica sol and the water;
pouring the weighed cement, aggregate, mineral admixture, water reducer and mixed liquor A into a planetary mortar stirrer to be stirred uniformly.
(3) And (3) putting the mixture obtained in the step (2) into a mold for molding, and putting the mold into a standard curing room for curing for 28 days with the mold.
The grafting rate of the modified silica sol is influenced differently by selecting different parameters, and experimental analysis shows that the grafting rate is increased along with the increase of the doping amount of the silane coupling agent, and is increased and then reduced along with the increase of the reaction temperature and the reaction time. According to the invention, the dispersibility of the silica sol is controlled by the grafting rate of the silane coupling agent, the higher the grafting rate is, the more obvious the steric hindrance effect is, and the better the dispersion effect of the nano-silica particles in the silica sol is, so that the advantages of the nano-particles can be better exerted, and the purpose of improving the performance of concrete and preparing high-strength concrete is achieved.
Example 4: graft ratio calculation (thermogravimetric testing)
And testing the grafting rate and grafting efficiency of the functionalized silica sol by adopting a thermogravimetric analyzer (HCT-2). Taking a functionalized silica sol sample of about 10mg for testing, adopting nitrogen as protective gas, wherein the nitrogen flow rate is 50mL min -2 The temperature rise range is between room temperature and 850 ℃, and the temperature rise rate is 10 ℃ for min -1 . The grafting ratio is calculated as follows
Grafting Rate (GR) (m1-m 2). times.100%/m 2(1)
Wherein m1 is the sample mass at the start of decomposition of the silane coupling agent, and m2 is the sample mass at the completion of decomposition of the silane coupling agent.
The modified silica sols of example 1(M-CNS1), example 2(M-CNS2), and example 3(M-CNS3) were subjected to several experiments, and the grafting ratio of example 1 was 35-40%, the grafting ratio of example 2 was 15-20%, and the grafting ratio of example 3 was 8-11%.
Example 5: infrared spectroscopy testing and morphology characterization
As shown in FIG. 2, it was found that the modification was followed by 2931cm after the modification compared to the control (CNS, without silica sol modification) -1 A distinct peak appears. Indicating that the silane coupling agent and the silica sol are compounded together. FIG. 1 is a transmission electron microscope image, with the left side showing silica sol and the right side showing modified silica sol.
Example 6: test of compression and bending strength of test block
The compression strength and the flexural strength were respectively tested on the Blank group (Blank, without adding silane coupling agent and silica sol, under the same conditions as in example 1), comparative control group (CNS), example 1(M-CNS1), example 2(M-CNS2), and example 3(M-CNS 3). Standard for measuring strength: GB/T17671 'cement mortar strength test method', the anti-breaking strength test block adopts a standard prism test piece with the size of 160x40x40 mm.
As shown in FIG. 3, it can be seen that the compressive strength and the flexural strength of example 1(M-CNS1) and example 2(M-CNS2) are improved to different degrees after silica sol modification, but the performance of example 3(M-CNS3) is partially reduced, indicating that proper conditions are also required for silica sol modification.
Example 7: determination of porosity
The specific data are shown in the following table, and it can be seen from fig. 4 and 5 that the porosity of each size of each test sample is obviously different after the silica sol is modified.
Example 8: chloride ion erosion resistance test
And (3) carrying out a chloride ion corrosion resistance test on each sample according to the standard for testing chloride ions: the GB/T50082-2009 common concrete long-term performance and durability test method is standard and is an RCM method.
The results of the chlorine ion erosion resistance tests were conducted from left to right on the Blank group (Blank, without adding the silane coupling agent and the silica sol, in the same condition as in example 1), comparative control group (CNS), example 1(M-CNS1), example 2(M-CNS2), and example 3(M-CNS 3). The length of the eroded area is measured by marking the horizontal line between the two vertical lines, and it can be seen that the erosion resistance of the silica sol is improved, the chloride ion migration coefficient is reduced, and the eroded area is obviously weakened in the example 1(M-CNS1), the example 2(M-CNS2) and the example 3(M-CNS 3).
Although the present invention has been described in detail by referring to the drawings in connection with the preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made on the embodiments of the present invention by those skilled in the art without departing from the spirit and scope of the present invention, and these modifications or substitutions are within the scope of the present invention/any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A preparation method of high-durability marine concrete doped with modified silica sol is characterized by comprising the following steps:
(1) preparing modified silica sol: respectively weighing a proper amount of silane coupling agent and silica sol, putting the silane coupling agent and the silica sol into a cosolvent consisting of a mixed solution of deionized water and ethanol, uniformly mixing, putting the mixture into a condensation reflux device, and cooling and collecting the solution after reaction after condensation reflux to obtain modified silica sol;
(2) weighing the following raw materials according to a formula: cement, water, aggregate, mineral admixture, water reducing agent and modified silica sol; adding the modified silica sol into water, and uniformly stirring to obtain a mixed solution, and uniformly mixing the mixed solution with the remaining raw materials of cement, water, aggregate, mineral admixture and water reducer;
(3) and (3) putting the mixture obtained in the step (2) into a mould for forming and maintaining.
2. The method for preparing high-durability marine concrete by adding modified silica sol according to claim 1, wherein the method comprises the following steps: the type of the silane coupling agent in the step (1) is KH550, KH560 or KH 570; the ratio of the silane coupling agent to the silica sol is 1:3-1: 5; the ultrasonic time for mixing evenly is 20-30 min; the condensing reflux temperature is 40-70 deg.C, pH is 2-9, and the condensing reflux time is 5-8 h.
3. The method for preparing high-durability marine concrete by adding modified silica sol according to claim 1, wherein the method comprises the following steps: the raw materials in the step (2) consist of the following components in parts by weight: portland cement: 400-600 parts of water: 140-210 parts of aggregate: 1200 plus 1800 portions, mineral admixture: 25-35 parts of a water reducing agent: 4-8 parts.
4. The method for preparing high-durability marine concrete by adding modified silica sol according to claim 1, wherein the method comprises the following steps: the aggregate in the step (2) comprises 10-20 parts by weight of 0.075-0.15mm aggregate, 60-80 parts by weight of 1.18-2.36mm aggregate and 160-180 parts by weight of 9.5-16mm aggregate.
5. The method for preparing high-durability marine concrete by adding modified silica sol according to claim 1, wherein the method comprises the following steps: the mineral admixture in the step (2) comprises 40 parts of fly ash and 60 parts of slag by weight.
6. The method for preparing high-durability marine concrete by adding modified silica sol according to claim 1, wherein the method comprises the following steps: the water reducing agent in the step (2) is a polycarboxylic acid water reducing agent, and the water reducing rate is 14-16%.
7. The method for preparing high-durability marine concrete by adding modified silica sol according to claim 1, wherein the method comprises the following steps: and (3) adding the silica sol obtained in the step (2) into water, and stirring for 3-5 min.
8. The method for preparing high-durability marine concrete by adding modified silica sol according to claim 1, wherein the method comprises the following steps: the pH value of the modified silica sol in the step (2) is 9-10, the adding proportion of the modified silica sol is 10-20 parts, the content of nano silica particles in the modified silica sol is 30% -50%, and the grafting rate of organic functional groups on the surfaces of the nano silica particles in the modified silica sol is 10% -40%.
9. The method for preparing the high-durability marine concrete doped with the modified silica sol as claimed in claim 1, comprising the steps of:
(1) preparing modified silica sol: respectively weighing a proper amount of silane coupling agent and silica sol in a beaker, preparing a mixed solution of deionized water and ethanol with a volume ratio of 1:1 as a cosolvent for later use, mixing the silane coupling agent, the silica sol and the cosolvent, carrying out ultrasonic mixing uniformly, putting the mixture into a flask of a condensation reflux device, adjusting the temperature and the pH, carrying out condensation reflux for a period of time, cooling and collecting the reacted solution, and thus obtaining the modified silica sol;
(2) weighing the following raw materials according to a formula: adding cement, water, aggregate, mineral admixture, water reducing agent and modified silica sol into water, and uniformly stirring to obtain a mixed solution A of the modified silica sol and the water;
pouring the weighed cement, aggregate, mineral admixture, water reducer and mixed liquor A into a planetary mortar stirrer to be uniformly stirred;
(3) and (3) putting the mixture obtained in the step (2) into a mold for molding, and putting the mold into a standard curing room for curing for 28 days with the mold.
10. Concrete obtainable by the method according to any one of claims 1 to 9.
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