阅读说明：本技术 一种杨梅状纳米硅颗粒的制备方法及其应用 (Preparation method and application of waxberry-shaped nano silicon particles ) 是由 王庆刚 侯鸿斌 郭健 陈骁 于 2021-01-08 设计创作，主要内容包括：本发明涉及一种杨梅状纳米硅颗粒的制备方法及其应用,属于建筑材料技术领域。本发明解决现有混凝土密封固化剂易泛白及强度提升有限的技术问题。本发明以超高比表面积杨梅状纳米硅颗粒等为原料,通过一步混合法制得了混凝土密封固化剂。本发明的固化剂有效利用杨梅状纳米硅颗粒的超高比表面积和微观结构特性,为纳米硅颗粒和混凝土中游离的钙离子提供了更多的反应活性位点,在形成稳定且牢固的C-S-H永久凝胶的同时,其本身也作为物理锚定点,进一步提升固化强度。经过均匀的渗透,固化剂能够形成致密坚固具有憎水效果的防护层,有效增强了混凝土的密实度,大幅提升了混凝土的坚固、耐磨、抗渗、防泛碱性能。(The invention relates to a preparation method and application of waxberry-shaped nano silicon particles, belonging to the technical field of building materials. The invention solves the technical problems that the existing concrete sealing curing agent is easy to whiten and the strength improvement is limited. The concrete sealing curing agent is prepared by taking myrica-shaped nano silicon particles with ultra-high specific surface area and the like as raw materials through a one-step mixing method. The curing agent effectively utilizes the characteristics of the ultra-high specific surface area and the microstructure of the waxberry-shaped nano silicon particles, provides more reactive active sites for the nano silicon particles and free calcium ions in concrete, and is used as a physical anchoring point while forming stable and firm C-S-H permanent gel, thereby further improving the curing strength. Through even infiltration, the curing agent can form compact firm inoxidizing coating that has the hydrophobic effect, has effectively strengthened the closely knit degree of concrete, has promoted firm, wear-resisting, impervious, the anti-saltpetering performance of concrete by a wide margin.)

1. A preparation method of waxberry-shaped nano silicon particles is characterized by comprising the following specific operation processes:

step 1, taking silane as a silicon raw material, deionized water as a solvent, taking micelle as a template, and stirring for reaction under the catalysis of an amine mineralizer to prepare a nano silicon particle solution;

step 2, concentrating the nano silicon particle solution by a rotary evaporation method to obtain stable nano silicon particle dispersion liquid, and drying to obtain the nano silicon particle dispersion liquid with the purity of more than 99%, the average particle size of 70-130 nm, and the specific surface area of 600-1000 m²·g^-1The myrica nano-silicon particles with ultra-high specific surface area;

the silane is tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltriethoxysilane, dimethyldiethoxysilane or ethyl polysilicate; the micelle is cetyl trimethyl ammonium bromide, lauryl sodium sulfate or cetyl trimethyl ammonium tosylate; the amine mineralizer is ammonia water, triethanolamine, ethylammonia, propylamine, butylammonia, diethylammonia or triethyl.

2. The method according to claim 1, wherein the method comprises the following steps:

firstly, dissolving 2.87g of hexadecyl trimethyl ammonium bromide and 35.27g of triethanolamine in 100mL of deionized water, transferring the solution into a 250mL three-neck flask, placing the three-neck flask into a 80 ℃ constant-temperature water bath pot after reagents are uniformly dispersed, and mechanically stirring the solution for 10.0 hours at the rotating speed of 800rpm by using a cantilever type stirrer;

then, adding 8.9mL of tetraethoxysilane, continuing stirring, and reacting for 20.0 h;

and finally, concentrating the reaction solution by a rotary evaporation method to obtain stable nano-silicon particle dispersion liquid, and drying to obtain myrica-shaped nano-silicon particles with ultrahigh specific surface area.

3. The concrete sealing and curing agent applying the waxberry-shaped nano silicon particles of claim 1, which is characterized by comprising the following raw materials in percentage by mass: 10-50% of waxberry-shaped nano silicon particles, 0.2-0.4% of catalyst, 0.2-1% of complexing agent, 0.03-0.05% of surfactant, 0.02-0.1% of wetting agent, 1-8% of water repellent and the balance of deionized water.

4. The concrete sealing curing agent of claim 3, wherein the curing agent comprises the following raw materials in percentage by mass: 20-40% of nano silicon particles, 0.2-0.4% of catalyst, 0.4-1% of complexing agent, 0.03-0.05% of surfactant, 0.04-0.08% of wetting agent, 2-6% of water repellent and the balance of deionized water.

5. The concrete sealing curing agent of claim 3, wherein the catalyst is one or more of sodium metaaluminate, potassium metaaluminate, sodium fluorosilicate, potassium fluorosilicate and sodium bicarbonate mixed in any proportion.

6. A concrete sealing curing agent as recited in claim 3, wherein said complexing agent is a mixture of disodium ethylenediaminetetraacetate and sodium hydroxide.

7. The concrete sealing curing agent of claim 3, wherein the surfactant is one or two of a fluorocarbon surfactant and a siloxane surfactant mixed in any ratio.

8. A concrete sealing curing agent as recited in claim 3, wherein said wetting agent is a silicone wetting agent.

9. The concrete sealing curing agent of claim 3, wherein the water repellent is one or more of sodium methyl silanol, potassium methyl silanol, sodium methyl silicate and potassium methyl silicate mixed in any proportion.

10. A method for preparing a concrete sealing curing agent as set forth in claim 3, characterized in that the method is carried out by the steps of: under normal temperature and pressure, uniformly mixing a water repellent, a complexing agent, a catalyst, a wetting agent and a surfactant, adding nano silicon particles, uniformly mixing again, adding the wetting agent, uniformly stirring, and reacting to obtain the concrete sealing curing agent.

Technical Field

The invention relates to a preparation method and application of waxberry-shaped nano silicon particles, belonging to the technical field of building materials.

Background

Modern buildings have increasingly high requirements on the strength and structural durability of concrete floors, and surface protection and treatment technologies of concrete are of particular importance. The concrete sealing curing agent is a preferable technical means for surface treatment of the concrete terrace due to the advantages of hardness, wear resistance, compression resistance, durability, environmental protection, attractiveness and the like. The concrete sealing curing agent is used as a good additive for protecting a concrete structure and prolonging the service life of concrete, is invented by Americans in the seventies of the last century, and is widely applied to the building decoration industry at present.

The current market mainly has four generations of products: the first generation is a magnesium-based curing agent which can improve the hardness and strength of the ground to a limited extent, but the curing agent is toxic and has poor environmental friendliness and timeliness; the second generation is a sodium-based curing agent, which can provide higher curing strength and durability, but has the problem of surface whitening due to the introduction of new metal salt; the third generation is a lithium-based curing agent, which solves the problem of second generation ground whitening while providing a higher curing effect, but the cost is high; the fourth generation is a silica gel type high-performance concrete sealing curing agent which has the advantages of strong curing timeliness, environmental friendliness, no whitening and the like, but has low curing strength due to less reactive active sites caused by the lower specific surface area, so that the large-scale application of the curing agent in the domestic building market is limited.

Therefore, based on the problems that the strength of the existing concrete sealing curing agent is improved to a limited extent and whitening is easy to occur, and the like, it is necessary to provide a concrete sealing curing agent with better performance and a preparation method thereof.

Disclosure of Invention

The invention provides a preparation method of waxberry-shaped nano silicon particles and a concrete sealing curing agent prepared by applying the preparation method, aiming at solving the technical problems that the strength of the existing concrete sealing curing agent is improved to a limited extent and the existing concrete sealing curing agent is easy to whiten.

The technical scheme of the invention is as follows:

a preparation method of waxberry-shaped nano silicon particles comprises the following specific operation processes:

step 1, taking silane as a silicon raw material, deionized water as a solvent, taking micelle as a template, and stirring to react at room temperature to 80 ℃ under the catalysis of an amine mineralizer to prepare a nano silicon particle solution;

step 2, concentrating the nano silicon particle solution by a rotary evaporation method to obtain stable nano silicon particle dispersion liquid, and drying to obtain the nano silicon particle dispersion liquid with the purity of more than 99%, the average particle size of 70-130 nm, and the specific surface area of 600-1000 m²·g^-1The myrica nano-silicon particles with ultra-high specific surface area.

Still further, silanes include, but are not limited to, ethyl orthosilicate, tetrapropoxysilane, tetrabutoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, or ethyl polysilicate.

Still further, micelles include, but are not limited to, cetyl trimethylammonium bromide, sodium dodecyl sulfate, or cetyl trimethylammonium tosylate.

Still further, amine mineralizers include, but are not limited to, ammonia, triethanolamine, ethylammonium, propylamine, butylammonium, diethylamine, or triethyl.

Furthermore, the specific operation process of the method is as follows:

firstly, dissolving 2.87g of hexadecyl trimethyl ammonium bromide and 35.27g of triethanolamine in 100mL of deionized water, transferring the solution into a 250mL three-neck flask, placing the three-neck flask into a 80 ℃ constant-temperature water bath pot after reagents are uniformly dispersed, and mechanically stirring the solution for 10.0 hours at the rotating speed of 800rpm by using a cantilever type stirrer;

then, adding 8.9mL of tetraethoxysilane, continuing stirring, and reacting for 20.0 h;

and finally, concentrating the reaction solution by a rotary evaporation method to obtain stable nano-silicon particle dispersion liquid, and drying to obtain myrica-shaped nano-silicon particles with ultrahigh specific surface area.

The waxberry-shaped nano silicon particle concrete sealing curing agent prepared by the method comprises the following raw materials in percentage by mass: 10-50% of waxberry-shaped nano silicon particles, 0.2-0.4% of catalyst, 0.2-1% of complexing agent, 0.03-0.05% of surfactant, 0.02-0.1% of wetting agent, 1-8% of water repellent and the balance of deionized water.

Further, the curing agent comprises the following raw materials in percentage by mass: 20-40% of waxberry-shaped nano silicon particles, 0.2-0.4% of catalyst, 0.4-1% of complexing agent, 0.03-0.05% of surfactant, 0.04-0.08% of wetting agent, 2-6% of water repellent and the balance of deionized water.

Furthermore, the catalyst is one or more of sodium metaaluminate, potassium metaaluminate, sodium fluosilicate, potassium fluosilicate and sodium bicarbonate which are mixed in any proportion.

Further, the complexing agent is a mixture of disodium ethylene diamine tetraacetate and sodium hydroxide.

Further, the surfactant is one or two of a fluorocarbon surfactant and a siloxane surfactant which are mixed in any proportion.

Further, the wetting agent is a silicone wetting agent.

Furthermore, the water repellent is one or more of sodium methyl silanol, potassium methyl silanol, sodium methyl silicate and potassium methyl silicate which are mixed in any proportion.

The preparation method of the concrete sealing curing agent comprises the steps of weighing all the raw materials according to the mass ratio, mixing at normal temperature and normal pressure, uniformly stirring, and obtaining the concrete sealing curing agent after the reaction is completed.

Further, the method comprises the following operation processes: under normal temperature and pressure, evenly mixing the catalyst, the complexing agent, the surfactant, the wetting agent and the water repellent, adding the nano silicon particles, evenly stirring and reacting to obtain the concrete sealing curing agent with the pH value of 8.0-12.0.

The invention has the following beneficial effects: the concrete sealing curing agent is prepared by taking myrica-shaped nano silicon particles with ultra-high specific surface area and the like as raw materials through a one-step mixing method. The concrete sealing curing agent provided by the invention also has the following advantages:

(1) the invention effectively utilizes the characteristics of the ultra-high specific surface area and the microstructure of the waxberry-shaped nano silicon particles, the waxberry-shaped microstructure enables the surfaces of the nano silicon particles to have complex and dense pore structures, not only provides the ultra-high specific surface area for the nano silicon particles, but also provides more reactive active sites for the nano silicon particles and free calcium ions in concrete, and the nano silicon particles and the free calcium ions can be used as physical anchor points to effectively improve the curing strength while forming stable and firm C-S-H permanent gel, and the curing agent can permeate pure silicon dioxide into capillary pores of the concrete, has no generation of redundant harmful ions, is nontoxic and harmless, can improve the strength of the concrete after being sprayed and cured by 40-50%, improve the wear resistance by 220-280%, reduce the water absorption by 120% and improve the glossiness by more than 200%.

(2) The nano silicon particles used in the invention areThe purity of the product produced by the method is more than 99 percent, the average particle size is 70-130 nm, and the specific surface area is 600-1000 m²·g^-1The nano silicon particles are the most important substances for the secondary chemical reaction of concrete, the waxberry-shaped microstructure of the material can effectively permeate into the concrete, more reactive active sites are provided for the nano silicon particles and the concrete through the structural advantage of high specific surface area, the nano silicon particles and the concrete undergo hydration reaction with free active calcium ions to generate new calcium silicate, and the nano silicon particles, the carbonate ions in the concrete and the precipitated Ca (OH) are added while the pores are filled₂Carrying out substitution reaction; the advantages of the waxberry-shaped dense pore structure can ensure that the nano silicon particles are firmly combined with the concrete, and compared with the whole curing plate, the nano silicon particles play a role of physical anchor points to further effectively improve the curing strength, so that the curing agent can be more uniformly permeated to form a compact and firm protective layer with a hydrophobic effect, the compactness of the concrete is effectively enhanced, and the firmness, wear resistance, permeability resistance and saltpetering resistance of the concrete are greatly improved.

(3) Because the single metaaluminate easily forms aluminum hydroxide gel to influence the catalytic effect, the catalyst for preparing the curing agent is a mixture of metaaluminate, fluosilicate and bicarbonate.

(4) The complexing agent is mainly used for complexing calcium ions in concrete, so that the curing reaction is slowed down to achieve the effect of deep penetration; the surfactant is a fluorocarbon surfactant or a siloxane surfactant, so that the surface tension of the curing agent can be effectively reduced, and the deep penetration effect is achieved; the water repellent is used for permeating into concrete to capture free carbonate ions, so that substitution reaction is carried out, micro-expansion is generated in capillary pores of the concrete, and the waterproof and anti-permeability functions of the concrete are further enhanced;

(5) the content of silicon dioxide in the curing agent prepared by the method is 10-40%, the solid content is more than 16%, the wear resistance ratio is more than 87%, and the compressive strength is more than 69MPa, so that the curing agent has excellent mechanical properties;

(6) the curing agent provided by the invention also has the characteristics of simple and convenient preparation method, simple production, environmental protection and convenient construction.

Drawings

FIG. 1A is a scanning electron microscope image of the myrica nano-silicon particles with ultra-high specific surface area under the magnification of 10 ten thousand times;

FIG. 1B is a scanning electron microscope image of the myrica nano-silicon particles with ultra-high specific surface area under the magnification of 30 ten thousand times;

FIG. 2A is a transmission electron microscope image of the myrica nano-silicon particles with ultra-high specific surface area under the magnification of 10 ten thousand times;

FIG. 2B is a transmission electron microscope image of the myrica nano-silicon particles with ultra-high specific surface area under the magnification of 30 ten thousand times;

FIG. 3 is a nitrogen adsorption and desorption curve of the myrica nano-silicon particles with ultra-high specific surface area;

FIG. 4A is a nitrogen adsorption/desorption curve of a conventional silica sol;

FIG. 4B is a nitrogen adsorption and desorption curve of the ultra-high specific surface area dendritic nano-silicon particles;

FIG. 5 is a scanning electron micrograph of a cross section of the cured concrete of example 4;

FIG. 6 is a scanning electron micrograph of the surface of the cured concrete of example 4.

Detailed Description

The experimental procedures used in the following examples are conventional unless otherwise specified. The materials, reagents, methods and apparatus used, unless otherwise specified, are conventional in the art and are commercially available to those skilled in the art.

The raw materials used in the following examples are all commercially available products except the myrica-shaped nano silicon particles with ultra-high specific surface area.

Preparing the myrica nano silicon particles with ultra-high specific surface area:

accurately weighing 2.87g of hexadecyl trimethyl ammonium bromide and 35.27g of triethanolamine by using an electronic analytical balance, taking 100mL of deionized water by using a measuring cylinder, completely dissolving the hexadecyl trimethyl ammonium bromide and the triethanolamine in distilled water, transferring the dissolved hexadecyl trimethyl ammonium bromide and the triethanolamine into a 250mL three-neck flask, placing the three-neck flask into a 80 ℃ constant-temperature water bath kettle after reagents are uniformly dispersed, and mechanically stirring the three-neck flask for 10.0h at the rotating speed of 800rpm by using a cantilever type stirrer. Then, 8.9mL of tetraethoxysilane is accurately weighed by a pipette and added into a three-neck flask for stirring, and the reaction time is 20.0 h. And then, concentrating the nano-silicon particle solution by a rotary evaporation method to obtain a stable nano-silicon particle dispersion solution, and drying to obtain the myrica-shaped nano-silicon particles with ultrahigh specific surface area.

The scanning electron microscope pictures of the obtained myrica nano-silicon particles with ultra-high specific surface area are shown in fig. 1A and 1B, and as can be seen from fig. 1A and 1B, micelles formed automatically by a surfactant and a mineralizer in deionized water are used as templates, and the micelles are prepared by adopting the surfactant and the mineralizerThe waxberry-shaped nano silicon particles prepared by the method have uniform particle size distribution and certain monodispersity, the average particle size of the nano particles is 100 +/-30 nm, the surfaces of the nano particles are rough and have dense microporous structures, and the result is generated after the micelle template is removed, which also means that the nano silicon particles have extremely high surface area. The transmission electron microscope pictures of the obtained myrica-shaped nano-silicon particles with ultra-high specific surface area are shown in fig. 2A and 2B, and it can be known from fig. 2A and 2B that under higher magnification, the myrica-shaped nano-silicon particles are obtainedThe silicon particles still have obvious micropores and waxberry-like structures inside, and the dense micropores and waxberry structures enable the nanoparticles to have more active reaction sites to be contacted with concrete.

The nitrogen adsorption and desorption curves of the obtained myrica nano-silicon particles with ultra-high specific surface area and the common silica sol are respectively shown in fig. 3 and fig. 4A.

The specific surface area and pore volume of the ordinary silica sol and the myrica nano-silicon particles with ultra-high specific surface area are compared, and are shown in the following table:

sample (I)	Specific surface area (BET)/m2·g-1	Pore volume (BJH)/cm3·g-1
			Waxberry-shaped nano silicon particles	857.30	0.44
Ordinary silica sol	164.81	0.76

The prepared myrica-shaped nano silicon particles with the ultrahigh specific surface area are used for preparing a concrete sealing curing agent.

Example 1

(1) The concrete sealing curing agent comprises the following raw materials in percentage by mass:

20% of myrica nano-silicon particles with ultra-high specific surface area, 0.6% of catalyst, 0.8% of complexing agent, 0.03% of surfactant, 0.07% of wetting agent, 5% of water repellent and 73.5% of deionized water.

Wherein the water repellent is sodium methylsiliconate; the complexing agent is a mixture of disodium ethylene diamine tetraacetate and sodium hydroxide, wherein the mass ratio of the disodium ethylene diamine tetraacetate to the sodium hydroxide is 1: 4; the catalyst is a mixture of sodium bicarbonate, magnesium fluosilicate and sodium metaaluminate, wherein the mass ratio of the sodium bicarbonate to the magnesium fluosilicate to the sodium metaaluminate is 1:2: 1; the surfactant is a siloxane surfactant; the wetting agent is a silicone wetting agent.

(2) Preparing a concrete sealing curing agent:

weighing all the raw materials according to the mass ratio, mixing at normal temperature and normal pressure, uniformly mixing the catalyst, the complexing agent, the wetting agent, the surfactant and the water repellent, adding the nano silicon particles, uniformly stirring, and reacting to obtain the curing agent in a clear and transparent state to obtain the concrete sealing curing agent.

Example 2

This example differs from example 1 in that: the concrete sealing curing agent comprises the following raw materials in percentage by mass: 30% of myrica nano-silicon particles with ultra-high specific surface area, 0.6% of catalyst, 1.2% of complexing agent, 0.04% of surfactant, 0.06% of wetting agent, 7% of water repellent and 61.1% of deionized water.

Wherein the water repellent is sodium methylsiliconate; the complexing agent is a mixture of disodium ethylene diamine tetraacetate and sodium hydroxide, wherein the mass ratio of the disodium ethylene diamine tetraacetate to the sodium hydroxide is 1: 5; the catalyst is a mixture of sodium bicarbonate, magnesium fluosilicate and sodium metaaluminate, wherein the mass ratio of the sodium bicarbonate to the magnesium fluosilicate to the sodium metaaluminate is 2:1: 1; the surfactant is a fluorocarbon surfactant; the wetting agent is a silicone wetting agent.

The concrete sealing curing agent was prepared in exactly the same manner as in example 1.

Example 3

This example differs from example 1 in that: the concrete sealing curing agent comprises the following raw materials in percentage by mass: 40% of myrica nano-silicon particles with ultra-high specific surface area, 0.6% of catalyst, 0.5% of complexing agent, 0.03% of surfactant, 0.07% of wetting agent, 6% of water repellent and 52.8% of deionized water.

Wherein the water repellent is sodium methylsiliconate; the complexing agent is a mixture of disodium ethylene diamine tetraacetate and sodium hydroxide, wherein the mass ratio of the disodium ethylene diamine tetraacetate to the sodium hydroxide is 1: 3; the catalyst is a mixture of sodium bicarbonate, magnesium fluosilicate and sodium metaaluminate, wherein the mass ratio of the sodium bicarbonate to the magnesium fluosilicate to the sodium metaaluminate is 1:1: 1; the surfactant is a fluorocarbon surfactant; the wetting agent is a silicone wetting agent.

The concrete sealing curing agent was prepared in exactly the same manner as in example 1.

Example 4

This example differs from example 1 in that: the concrete sealing curing agent comprises the following raw materials in percentage by mass: 40% of myrica nano-silicon particles with ultra-high specific surface area, 0.4% of catalyst, 1% of complexing agent, 0.03% of surfactant, 0.07% of wetting agent, 5% of water repellent and 53.5% of deionized water.

Wherein the water repellent is methyl potassium silicate; the complexing agent is a mixture of disodium ethylene diamine tetraacetate and sodium hydroxide, wherein the mass ratio of the disodium ethylene diamine tetraacetate to the sodium hydroxide is 1: 2; the catalyst is a mixture of sodium bicarbonate, magnesium fluosilicate and sodium metaaluminate, wherein the mass ratio of the sodium bicarbonate to the magnesium fluosilicate to the sodium metaaluminate is 1:2: 1; the surfactant is a siloxane surfactant; the wetting agent is a silicone wetting agent.

The concrete sealing curing agent was prepared in exactly the same manner as in example 1.

Comparative example 1:

preparing the dendritic nano silicon particles with the ultrahigh specific surface area:

accurately weighing 3.52g of hexadecyl trimethyl ammonium bromide, 2.38g of lauryl sodium sulfate and 5.27g of triethanolamine by using an electronic analytical balance, taking 100mL of deionized water by using a measuring cylinder, completely dissolving the hexadecyl trimethyl ammonium bromide, the lauryl sodium sulfate and the triethanolamine in distilled water, transferring the dissolved solution into a 250mL three-neck flask, placing the three-neck flask into a 80 ℃ constant-temperature water bath after reagents are uniformly dispersed, and mechanically stirring the solution for 10.0h at the rotating speed of 800rpm by using a cantilever type stirrer. Then, 5.6mL of tetraethoxysilane accurately weighed by a pipette is added into a three-neck flask for stirring, and the reaction time is 20.0 h. And then, concentrating the nano silicon particle solution by a rotary evaporation method to obtain a stable nano silicon particle dispersion solution, and drying to obtain the dendritic nano silicon particles with ultra-high specific surface area, wherein the average particle size is 100 +/-30 nm.

The nitrogen adsorption and desorption curve of the obtained ultra-high specific surface area dendritic nano-silicon particles is shown in fig. 4B.

Specific surface area and pore volume of ultra-high specific surface area dendritic nano-silicon particles are compared as shown in the following table:

sample (I)	Specific surface area (BET)/m2·g-1	Pore volume (BJH)/cm3·g-1
			Dendritic nano silicon particles with ultrahigh specific surface area	554.03	1.93

The prepared myrica-shaped nano silicon particles with the ultrahigh specific surface area are used for preparing a concrete sealing curing agent.

This comparative example differs from example 4 in that: this comparative example uses ultra-high specific surface area dendritic nano-silicon particles instead of the ultra-high specific surface area myrica nano-silicon particles of example 4.

Comparative example 2

This comparative example differs from example 4 in that: this comparative example uses a common silica sol instead of the ultra-high specific surface area myrica-like nano-silica particles of example 4.

Comparative example 3

This comparative example differs from example 4 in that: no catalyst was added in this comparative example.

The properties of the concrete sealing and curing agent obtained in the above examples and comparative examples can be characterized:

the test method comprises the following steps: the curing agent obtained in examples 1-4 and comparative examples 1 and 2 was brushed on the surface of a concrete test block of 10X 10cm by a brush, brushing was repeated after one hour, during which, the brush was not stopped and brushing was repeated until the curing agent appeared viscous, finally, the surface excess curing agent was removed by deionized water, and after drying, the surface was polished by 400#, 800#, 1500# and 3000# abrasive discs, respectively. The solid content of the curing agent and the 24-hour surface water absorption capacity, the wear resistance ratio, the hardness and the compressive strength of the cured concrete are compared.

The test results are shown in the following table:

as can be seen from the above table, the curing agent of the present invention has a solid content of 16% or more, an abrasion resistance ratio of 87% or more, and a compressive strength of 69MPa or more, and the surface water absorption capacity for 24 hours, abrasion resistance ratio and compressive strength of comparative examples 1, 2 and 3 are inferior to those of the curing agents prepared in examples 1 to 4 of the present invention.

Scanning electron microscope pictures of the cross section and the surface of the concrete cured by the concrete sealing curing agent obtained in the embodiment 4 are respectively shown in fig. 5 and fig. 6, wherein the circle in the pictures is myrica-shaped nano silicon particles with ultra-high specific surface area, and the pictures show that the concrete sealing curing agent obtained in the embodiment 4 has completely penetrated on an observable nanoscale, and the penetration depth is 5-8 mm.