CN108947290B - Method for improving cement-based material pore structure by using high-dispersity nano silicon dioxide - Google Patents
Method for improving cement-based material pore structure by using high-dispersity nano silicon dioxide Download PDFInfo
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims abstract description 87
- 239000004568 cement Substances 0.000 title claims abstract description 84
- 239000011148 porous material Substances 0.000 title claims abstract description 60
- 239000000463 material Substances 0.000 title claims abstract description 32
- 235000012239 silicon dioxide Nutrition 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 title claims abstract description 24
- 239000005543 nano-size silicon particle Substances 0.000 title claims abstract description 23
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 48
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 36
- 238000003756 stirring Methods 0.000 claims abstract description 20
- 239000003607 modifier Substances 0.000 claims abstract description 18
- 238000002156 mixing Methods 0.000 claims abstract description 17
- 239000006185 dispersion Substances 0.000 claims abstract description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 15
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 9
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 claims description 6
- 239000003999 initiator Substances 0.000 claims description 5
- 238000005303 weighing Methods 0.000 claims description 4
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 3
- DKIDEFUBRARXTE-UHFFFAOYSA-N 3-mercaptopropanoic acid Chemical compound OC(=O)CCS DKIDEFUBRARXTE-UHFFFAOYSA-N 0.000 claims description 3
- ZZZCUOFIHGPKAK-UHFFFAOYSA-N D-erythro-ascorbic acid Natural products OCC1OC(=O)C(O)=C1O ZZZCUOFIHGPKAK-UHFFFAOYSA-N 0.000 claims description 3
- 239000004721 Polyphenylene oxide Substances 0.000 claims description 3
- 229930003268 Vitamin C Natural products 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims description 3
- FWDBOZPQNFPOLF-UHFFFAOYSA-N ethenyl(triethoxy)silane Chemical compound CCO[Si](OCC)(OCC)C=C FWDBOZPQNFPOLF-UHFFFAOYSA-N 0.000 claims description 3
- 239000010881 fly ash Substances 0.000 claims description 3
- 230000002572 peristaltic effect Effects 0.000 claims description 3
- 229920000570 polyether Polymers 0.000 claims description 3
- 229910021487 silica fume Inorganic materials 0.000 claims description 3
- 238000003786 synthesis reaction Methods 0.000 claims description 3
- 235000019154 vitamin C Nutrition 0.000 claims description 3
- 239000011718 vitamin C Substances 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 claims description 2
- 239000002131 composite material Substances 0.000 claims description 2
- 239000000178 monomer Substances 0.000 claims description 2
- 238000004321 preservation Methods 0.000 claims description 2
- 238000000746 purification Methods 0.000 claims description 2
- 239000002893 slag Substances 0.000 claims description 2
- 238000001308 synthesis method Methods 0.000 claims description 2
- 238000001132 ultrasonic dispersion Methods 0.000 claims description 2
- 239000000203 mixture Substances 0.000 abstract description 15
- 239000004567 concrete Substances 0.000 abstract description 11
- 239000002002 slurry Substances 0.000 abstract description 3
- 229920005646 polycarboxylate Polymers 0.000 abstract 1
- 230000008092 positive effect Effects 0.000 abstract 1
- 239000008030 superplasticizer Substances 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 12
- 239000000243 solution Substances 0.000 description 9
- 239000000126 substance Substances 0.000 description 8
- 238000001035 drying Methods 0.000 description 6
- 230000036571 hydration Effects 0.000 description 6
- 238000006703 hydration reaction Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 239000007864 aqueous solution Substances 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 238000009210 therapy by ultrasound Methods 0.000 description 4
- 239000000654 additive Substances 0.000 description 3
- 230000000996 additive effect Effects 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 229910052681 coesite Inorganic materials 0.000 description 3
- 229910052593 corundum Inorganic materials 0.000 description 3
- 229910052906 cristobalite Inorganic materials 0.000 description 3
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 3
- 229910052753 mercury Inorganic materials 0.000 description 3
- 239000002105 nanoparticle Substances 0.000 description 3
- 229910052682 stishovite Inorganic materials 0.000 description 3
- 229910052905 tridymite Inorganic materials 0.000 description 3
- 229910001845 yogo sapphire Inorganic materials 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- VTYYLEPIZMXCLO-UHFFFAOYSA-L calcium carbonate Substances [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 230000005476 size effect Effects 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
-
- 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
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention provides a method for improving a cement-based material pore structure by using high-dispersity nano-silica. Uniformly mixing the high-dispersity nano silicon dioxide with water, and stirring the mixture with a cementing material to improve the pore structure of a cement-based material; wherein, the water-to-cement ratio is controlled to be between 0.25 and 0.55, and the mixing amount of the high-dispersion nano silicon dioxide is controlled to be between 1.0 and 5.0 percent of the mass of the cement. According to the invention, the polycarboxylate superplasticizer (hereinafter referred to as modifier PCE) is utilized to modify the nano-silica, so that the dispersion degree of the nano-silica in a cement system is improved, and the improvement efficiency of the nano-silica to the pore structure in the cement system is fully exerted. The method reduces the volume of harmful pores and harmful pores, increases the volume of harmful pores and harmful pores, makes the early microstructure of hardened cement slurry more compact, and has a positive effect on improving the durability of concrete.
Description
Technical Field
The invention relates to a technology for improving a cement-based material pore structure by using high-dispersity nano-silica, belonging to the technical field of building materials.
Background
The pore structure of concrete is a key factor affecting its durability. Wherein, the influence of the concrete pore structure on the durability is mainly reflected in the aspects of frost resistance, impermeability, carbonization resistance and the like. In a text published by silicate journal of the recent development of concrete science and technology by Wuzhong Wei academy in 1979, the pore structure in concrete is divided into harmless pores (<20nm), less harmful pores (20-50 nm), harmful pores (50-200 nm) and more harmful pores (>200 nm). Reducing pore volume with pore diameter of >100nm and increasing pore volume with pore diameter of <50nm has favorable effects on macroscopic mechanical property and durability of concrete. The traditional method for improving the pore structure of concrete mainly utilizes mineral admixtures (silica fume, fly ash and the like), and the method needs a larger mixing amount to have obvious improvement effect. And because mineral admixtures are generally low in activity, excessive use tends to result in slow development of early strength of the concrete.
In recent years, the development of nanotechnology has injected new development power into the field of civil engineering. Wherein, the nano material is added into the cement-based material to improve various properties of the cement-based materialOne of its important applications. Especially, the nano particles have small size effect, which provides a new way for improving the pore structure of the cement-based material and is receiving extensive attention. Many scholars surround the nano SiO2TiO 2 nanoparticles2Nano Al2O3Nano CaCO, nano-grade CaCO3And graphene and the like have been studied and made important progress.
However, nanoparticles are extremely prone to agglomeration in cement systems, which limits their filling effect on the pore structure and even adversely affects the pore structure of concrete.
Meanwhile, additive products specially used for improving the pore structure of concrete are lacked in the market. Aiming at the problems, the invention uses the modified high-dispersity nano-silica as an additive of a cement-based material to obviously improve the pore structure of the hardened cement slurry under the condition of low doping amount.
Disclosure of Invention
The technical problem is as follows: the invention aims to improve the pore size distribution of a cement-based material and the compactness of hardened cement paste by using the modified nano-silica as an additive, thereby improving the durability of the cement-based material.
The technical scheme is as follows: the method for improving the pore structure of the cement-based material by using the high-dispersity nano-silica comprises the steps of uniformly mixing the high-dispersity nano-silica with water, and stirring the mixture with a cementing material to improve the pore structure of the cement-based material; wherein, the water-to-cement ratio is controlled to be between 0.25 and 0.55, and the mixing amount of the high-dispersion nano silicon dioxide is controlled to be between 1.0 and 5.0 percent of the mass of the cement.
Wherein,
the synthesis method of the high-dispersity nano silicon dioxide comprises the following steps:
the method comprises the following steps: synthesis of modifier PCE
Acetic acid was first added dropwise to the polyether solution, stirred in a water bath and subsequently H was added dropwise2O2And vinyl triethoxysilane, automatically dripping an initiator into the three-neck flask by using a peristaltic pump, preserving heat in a water bath after finishing dripping, dripping NaOH solution, and finally preparing the mixtureForming a modifier PCE;
step two: grafting of modifier PCE
Weighing unmodified nano-silica sol and the modifier PCE according to the mass ratio of 3: 1-5: 1, dropwise adding the weighed modifier into the unmodified nano-silica sol, and reacting in a water bath to obtain high-dispersity nano-silica;
step three: purification of high-dispersity nano silicon dioxide
And D, dialyzing and purifying the high-dispersity nano silicon dioxide prepared in the step two to remove the modifier which is not grafted to the surface of the silicon dioxide and unreacted monomers.
The cementing material comprises a simple cement system or a composite cementing system formed by mixing a cement system with fly ash, silica fume and slag.
And mixing the high-dispersity nano silicon dioxide with water, and performing ultrasonic dispersion for more than 3 minutes and stirring dispersion for more than 3 minutes after mixing.
The high-dispersion nano silicon dioxide is stirred with the cementing material, and the stirring system is slow stirring for 1-2 min and fast stirring for 1-2 min.
The temperature of the cement-based material is controlled to be 15-35 ℃, the curing temperature is controlled to be 15-35 ℃, and the humidity is controlled to be more than 80%.
Stirring in the water bath in the step one is carried out for 10-20 min in the water bath at the temperature of 40 +/-2 ℃, and the stirring speed is 300 +/-5 rpm; the heat preservation in the water bath is carried out for 10-20 min in the water bath at the temperature of 40 +/-2 ℃.
The initiator in the first step is as follows: acrylic acid: vitamin C: mercaptopropionic acid: water-12.3: 0.79; 0.82: 50-12.5: 0.83:0.86: 52.
The concentration of the NaOH solution dripped in the step one is 3.5-3.8 mM.
And the reaction in the water bath in the step two is carried out for 3.5-4 h in the water bath at the temperature of 40 +/-2 ℃.
The use method of the high-dispersity nano silicon dioxide comprises the following steps: and calculating the mass fraction of the purified high-dispersity nano silicon dioxide. Weighing the high-dispersity nano silicon dioxide with corresponding mass, uniformly mixing with water, adding into the cementing material, and mixing.
Has the advantages that: the high-dispersity nano silicon dioxide can reduce the volumes of harmful holes and harmful holes, increase the volumes of harmless holes and less harmful holes, improve the hole structure of hardened cement paste and improve the durability of concrete.
Detailed Description
1. Synthesis of modifier PCE
Firstly, 0.5 +/-0.1 g of acetic acid is dripped into 200 +/-5 g of polyether solution, and the mixture is stirred for 10-20 min in water bath at the temperature of 40 +/-2 ℃ and the stirring speed is 300 +/-5 rpm. Subsequently, 2. + -. 0.05gH was added dropwise2O2And 4.5 +/-0.1 g of vinyltriethoxysilane, automatically dropwise adding the prepared initiator ((12.4 +/-0.1) g of acrylic acid + (0.81 +/-0.02) g of vitamin C + (0.84 +/-0.02) g of mercaptopropionic acid + (51 +/-1) g of water) into a three-neck flask by using a peristaltic pump, dropwise adding for 85-95 min, after the dropwise adding is completed, preserving the temperature in a water bath at 40 +/-2 ℃ for 10-20 min, and automatically dropwise adding a 3.6mM NaOH solution to finally prepare the synthetic modifier PCE;
2. grafting of modifier PCE
Weighing the alkaline silica sol and the modifier according to the mass ratio of 3:1, automatically dripping the modifier with the corresponding mass within 25-30 min, and reacting in a water bath at the temperature of 40 +/-2 ℃ for 3.5-4 h. Obtaining high-dispersity nano silicon dioxide;
the general applicability of the present invention will be illustrated by the following specific examples.
Example 1
50g of P.I 42.5 type reference cement (the chemical composition of the cement is shown in Table 1) is weighed, modified nano-silica (the particle size is 15nm) accounting for 1.5% of the mass of the cement is taken, the ratio of water to cement for experiments is 0.5, and the mass of the taken water (minus the mass of water in the modified nano-silica solution) is weighed. Firstly, fully mixing the modified nano silicon dioxide with high dispersibility with water, carrying out ultrasonic treatment for 3 minutes and stirring for 3 minutes. Then, the mixed aqueous solution is added into cement, and the mixture is stirred slowly for 1min and quickly for 1min by a stirrer. The experimental temperature was 20 ℃. And pouring the freshly mixed cement paste into a mold, curing for 3 days in air, stopping hydration, and performing drying test, wherein the curing temperature is 20 ℃ and the relative humidity is 85%.
TABLE 1 chemical composition of type P I42.5 cement
| Oxide | CaO | SiO2 | Fe2O3 | Al2O3 | SO3 | MgO | K2O |
| Wt％ | 68.0 | 18.1 | 3.6 | 3.7 | 4.2 | 1.8 | 0.9 |
Example 2
50g of type P.II cement (the chemical composition of the cement is shown in Table 2) of the small wild field is weighed, 1.5 percent of modified nano-silica (the particle size is 15nm) of the mass of the cement is taken, the ratio of water to cement for experiments is 0.5, and the mass of the taken water (minus the mass of water in the modified nano-silica solution) is weighed. Firstly, fully mixing the modified nano silicon dioxide with high dispersibility with water, carrying out ultrasonic treatment for 3 minutes and stirring for 3 minutes. Then, the mixed aqueous solution is added into cement, and the mixture is stirred slowly for 1min and quickly for 1min by a stirrer. The experimental temperature was 20 ℃. And pouring the freshly mixed cement paste into a mold, curing for 3 days in air, stopping hydration, and performing drying test, wherein the curing temperature is 20 ℃ and the relative humidity is 85%.
TABLE 2 chemical composition of P.II type 52.5 cement
| Oxide | CaO | SiO2 | Fe2O3 | Al2O3 | SO3 | MgO | K2O |
| Wt％ | 63.62 | 19.70 | 2.93 | 4.45 | 2.93 | 1.28 | 0.68 |
Comparative example 1
50g of P.I 42.5 type reference cement (the chemical composition of the cement is shown in Table 1) is weighed, and 25g of water is taken. 25g of water was added to the cement. Stirring slowly for 1min and rapidly for 1min by using a stirrer. The experimental temperature was 20 ℃. And pouring the freshly mixed cement paste into a mold, curing for 3 days in air, stopping hydration, and performing drying test, wherein the curing temperature is 20 ℃ and the relative humidity is 85%.
Comparative example 2
50g of type P.II cement (chemical composition of cement is shown in Table 2) in a small wild field is weighed, and 25g of water is taken. 25g of water was added to the cement. Stirring slowly for 1min and rapidly for 1min by using a stirrer. The experimental temperature was 20 ℃. And pouring the freshly mixed cement paste into a mold, curing for 3 days in air, stopping hydration, and performing drying test, wherein the curing temperature is 20 ℃ and the relative humidity is 85%.
Comparative example 3
50g of P.I 42.5 type cement (the chemical composition of the cement is shown in Table 1) is weighed, unmodified nano-silica (the particle size is 15nm) accounting for 1.5% of the mass of the cement is taken, the ratio of water to cement for experiments is 0.5, and the mass of taken water (minus the mass of water in the unmodified nano-silica solution) is weighed. First, fully mixing unmodified nano silicon dioxide with water, carrying out ultrasonic treatment for 3 minutes, and stirring for 3 minutes. Then, the mixed aqueous solution is added into cement, and the mixture is stirred slowly for 1min and quickly for 1min by a stirrer. The experimental temperature was 20 ℃. And pouring the freshly mixed cement paste into a mold, curing for 3 days in air, stopping hydration, and performing drying test, wherein the curing temperature is 20 ℃ and the relative humidity is 85%.
Comparative example 4
50g of type P.II cement (chemical composition of cement is shown in Table 2) in the small wild field is weighed, unmodified nano-silica (particle size is 15nm) accounting for 1.5% of the mass of the cement is taken, the ratio of water to cement for experiment is 0.5, and the mass of taken water (minus the mass of water in the unmodified nano-silica solution) is weighed. First, fully mixing unmodified nano silicon dioxide with water, carrying out ultrasonic treatment for 3 minutes, and stirring for 3 minutes. Then, the mixed aqueous solution is added into cement, and the mixture is stirred slowly for 1min and quickly for 1min by a stirrer. The experimental temperature was 20 ℃. And pouring the freshly mixed cement paste into a mold, curing for 3 days in air, stopping hydration, and performing drying test, wherein the curing temperature is 20 ℃ and the relative humidity is 85%.
The pore structure inside the hardened cement paste of examples 1-2 and comparative examples 1-4 was characterized using an automatic mercury porosimeter model Poremaster GT-60 manufactured by Quanta Chrome, USA. The test method refers to GB/T21650.1-2008 mercury intrusion method and gas adsorption method to determine the first part of the pore size distribution and porosity of the solid material: mercury intrusion method.
The pore structure of the hardened cement paste was classified by the pore structure classification method proposed by wuzhongwei academy. The classification method comprises the following steps: harmless pores (<20nm), less harmful pores (20-100 nm), harmful pores (100-200 nm), more harmful pores (>200nm)
The hardened cement pastes prepared in examples 1 to 2 and comparative examples 1 to 4 had pore structure distributions as shown in Table 3 below
Table 3 examples 1-2 and comparative examples 1-4 statistics of pore structure distribution in hardened cement slurries
From the results of examples, it can be seen that the untreated nanosilica improves the volume of harmless pores and less harmful pores to some extent, but causes a large increase in harmful pores, having an adverse effect on the pore structure of hardened cement paste, as compared to comparative examples 1 and 3 and comparative examples 2 and 4. In contrast, in comparative example 1 and comparative example 1, and in example 2 and comparative example 2, it was found that the highly dispersed nano silica particles used in the examples improve the pore structure of the hardened cement paste in the early stage by reducing the volume of harmful pores and harmful pores while increasing the volume of harmless pores and less harmful pores.
The effect of the highly dispersible nanosilica on the improvement of the early pore structure of hardened cement paste is demonstrated by the above examples.
Claims (9)
1. A method for improving the pore structure of a cement-based material by using high-dispersity nano-silica is characterized in that the high-dispersity nano-silica is uniformly mixed with water and then is stirred with a cementing material to improve the pore structure of the cement-based material; wherein, the water-to-gel ratio is controlled to be between 0.25 and 0.55, and the mixing amount of the high-dispersion nano silicon dioxide is controlled to be between 1.0 and 5.0 percent of the mass of the cement;
the synthesis method of the high-dispersity nano silicon dioxide comprises the following steps:
the method comprises the following steps: synthesis of modifier PCE
Acetic acid was first added dropwise to the polyether solution, stirred in a water bath and subsequently H was added dropwise2O2And vinyl triethoxysilane, automatically dripping an initiator into the three-neck flask by using a peristaltic pump, preserving heat in a water bath after finishing dripping, and dripping a NaOH solution to finally prepare a synthetic modifier PCE;
step two: grafting of modifier PCE
Weighing unmodified nano-silica sol and the modifier PCE according to the mass ratio of 3: 1-5: 1, dropwise adding the weighed modifier into the unmodified nano-silica sol, and reacting in a water bath to obtain high-dispersity nano-silica;
step three: purification of high-dispersity nano silicon dioxide
And D, dialyzing and purifying the high-dispersity nano silicon dioxide prepared in the step two to remove the modifier which is not grafted to the surface of the silicon dioxide and unreacted monomers.
2. The method for improving the pore structure of cement-based materials by using highly dispersible nano-silica as claimed in claim 1, wherein the cement material comprises a pure cement system or a composite cement system obtained by blending a cement system with fly ash, silica fume and slag.
3. The method for improving the pore structure of the cement-based material by using the high-dispersity nano-silica as claimed in claim 1, wherein the high-dispersity nano-silica is mixed with water, and after mixing, ultrasonic dispersion is carried out for more than 3 minutes, and stirring dispersion is carried out for more than 3 minutes.
4. The method for improving the pore structure of the cement-based material by using the high-dispersity nano-silica as claimed in claim 1, wherein the high-dispersity nano-silica is stirred with the cementing material by a slow stirring system for 1-2 min and a fast stirring system for 1-2 min.
5. The method for improving the pore structure of the cement-based material by using the high-dispersity nano-silica as claimed in claim 1, wherein the temperature of the cement-based material is controlled to be 15-35 ℃, the curing temperature is controlled to be 15-35 ℃, and the humidity is controlled to be more than 80%.
6. The method for improving the pore structure of the cement-based material by using the high-dispersity nano-silica as claimed in claim 1, wherein the stirring in the water bath in the first step is performed at a stirring speed of 300 +/-5 rpm for 10-20 min at a temperature of 40 +/-2 ℃; the heat preservation in the water bath is carried out for 10-20 min in the water bath at the temperature of 40 +/-2 ℃.
7. The method for improving the pore structure of cement-based materials by using highly dispersible nano-silica as claimed in claim 1, wherein the initiator in the first step is: acrylic acid: vitamin C: mercaptopropionic acid: water is 12.3:0.79:0.82: 50-12.5: 0.83:0.86: 52.
8. The method for improving the pore structure of the cement-based material by using the highly dispersible nano-silica as claimed in claim 1, wherein the concentration of the NaOH solution added dropwise in the step one is 3.5-3.8 mM.
9. The method for improving the pore structure of the cement-based material by using the high-dispersity nano-silica as claimed in claim 1, wherein the reaction in the water bath in the second step is carried out in a water bath at a temperature of 40 +/-2 ℃ for 3.5-4 h.
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| CN109133765A (en) * | 2018-08-25 | 2019-01-04 | 太和县鑫泰高科新型建筑材料有限公司 | A method of with the modified enhancing cement-base composite material of thermal reduction graphene-carbon nano tube |
| CN111410481B (en) * | 2020-03-31 | 2022-01-28 | 河海大学 | Core-shell nanoparticle modified cement-based protective material and preparation method thereof |
| CN111456354A (en) * | 2020-04-22 | 2020-07-28 | 河南派普建工集团有限公司 | Wall surface construction method |
| CN111909566A (en) * | 2020-08-19 | 2020-11-10 | 广东博智林机器人有限公司 | Coating modifier, coating and preparation method thereof |
| CN112408876B (en) * | 2020-11-09 | 2022-05-31 | 西南科技大学 | Cement-based porous material based on silicon dioxide and preparation method thereof |
| CN112299466B (en) * | 2020-12-07 | 2022-10-11 | 江西华明纳米碳酸钙有限公司 | Preparation method of nano calcium carbonate for cement mortar |
| CN113698548A (en) * | 2021-08-31 | 2021-11-26 | 湖北恒利建材科技有限公司 | High-performance polycarboxylate superplasticizer and preparation method thereof |
| CN114455882B (en) * | 2022-01-05 | 2022-12-16 | 江苏奥莱特新材料股份有限公司 | Preparation method and application of multifunctional nano composite material for concrete |
| CN114292042B (en) * | 2022-01-19 | 2023-03-17 | 合肥工业大学 | Preparation method of high-hydrophilicity comb-shaped polymer grafting machine-made sand |
| CN114368932A (en) * | 2022-01-28 | 2022-04-19 | 广东石油化工学院 | Oil well cement modifier |
| CN114835454A (en) * | 2022-05-30 | 2022-08-02 | 东南大学 | Method for improving early performance of slag cement with large mixing amount by using nano silicon dioxide |
| CN115403334A (en) * | 2022-09-01 | 2022-11-29 | 东南大学 | Nano reinforced engineering cement-based composite material and preparation method thereof |
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| CZ2010855A3 (en) * | 2010-11-23 | 2012-05-30 | Rázl@Ivan | Cement composites resistant to acids and high temperature values and process for preparing thereof |
| CN102863823B (en) * | 2012-09-19 | 2014-07-09 | 常州大学 | Preparation method of modified nano silicon dioxide |
| CN103664028B (en) * | 2013-11-01 | 2015-12-30 | 西安理工大学 | The dispersing method of nano oxidized silica flour in cement-based material |
| CN104530769B (en) * | 2015-01-20 | 2016-05-25 | 南昌航空大学 | A kind of preparation method of high dispersancy nano silicon dioxide granule |
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