1. The cement-based composite slurry for 3D printing is characterized by comprising the following raw materials in parts by weight: 30-50 parts of portland cement, 8-12 parts of Baozhu sand, 6-8 parts of modified zirconia ceramic whisker, 4-6 parts of modified boron carbide ceramic whisker, 10-20 parts of polyurethane modified epoxy resin emulsion, 0.2-0.4 part of sodium lignosulfonate, 1-2 parts of polysilazane and 20-40 parts of deionized water.

2. The cement-based composite slurry for 3D printing according to claim 1, wherein the modified zirconia ceramic whiskers comprise the following raw materials in parts by weight: 20-40 parts of zirconia ceramic whisker, 5-10 parts of vinyltriethoxysilane, and 100-200 parts of anhydrous ethanol.

3. The cement-based composite paste for 3D printing according to claim 2, wherein the zirconia ceramic whiskers have an average diameter of 40-80 μ ι η.

4. The cement-based composite paste for 3D printing according to claim 2, wherein the modified zirconia ceramic whiskers are prepared by the steps of:

adding the zirconia ceramic whisker and the vinyltriethoxysilane into absolute ethyl alcohol, placing the mixture into an ultrasonic dispersion machine for ultrasonic treatment for 30-40min, filtering and drying to obtain the modified zirconia ceramic whisker.

5. The cement-based composite slurry for 3D printing according to claim 4, wherein the ultrasonic treatment condition is frequency of 20-40kHz and power of 400-600W.

6. The cement-based composite slurry for 3D printing according to claim 1, wherein the modified boron carbide ceramic whiskers comprise the following raw materials in parts by weight: 10-20 parts of boron carbide ceramic whiskers, 5-10 parts of ethyl orthosilicate, 20-40 parts of ammonia water with the mass fraction of 10% and 40-60 parts of absolute ethyl alcohol.

7. The cement-based composite paste for 3D printing according to claim 6, wherein the boron carbide ceramic whiskers have an average diameter of 40-60 μm.

8. The cement-based composite paste for 3D printing according to claim 6, wherein the modified boron carbide ceramic whiskers are prepared by the following steps:

(1) adding boron carbide ceramic whiskers into absolute ethyl alcohol, and performing ultrasonic dispersion for 20-30min at normal temperature to obtain a dispersion liquid;

(2) adding ammonia water into the dispersion liquid, introducing nitrogen for protection, slowly dropwise adding ethyl orthosilicate, stirring and reacting for 1-2h under the water bath condition of 40-60 ℃ at the rotating speed of 400-600r/min, centrifugally separating, washing the solid with absolute ethyl alcohol for 3-5 times, and drying in vacuum to obtain the modified boron carbide ceramic whisker.

9. The cement-based composite slurry for 3D printing according to claim 8, wherein the ultrasonic dispersion conditions in step (2) are 20-30kHz and 400W of power.

10. The preparation method of the cement-based composite slurry for 3D printing is characterized by comprising the following steps of:

(1) adding the polyurethane modified epoxy resin emulsion and polysilazane into water, stirring and mixing to obtain mixed emulsion;

(2) and adding the Portland cement, the Baozhu sand, the modified zirconia ceramic whisker, the modified boron carbide ceramic whisker and the sodium lignosulfonate into the mixed emulsion, and stirring and mixing to obtain the cement-based composite slurry for 3D printing.

Background

With the continuous improvement of the technological level, the 3D printing technology is rapidly changing the production and living styles of people. In the construction industry, the "contour process" of 3D printing technology is applied, where a nozzle extrudes building material at a given location, as dictated by a design drawing, to build an object by printing layer by layer. Cement is a hydraulic cementing material, is one of the most important building materials in building engineering, and is mainly used for preparing concrete, mortar and grouting materials. The appearance of 3D printing cement makes 3D printing technique more mature and convenient, also safer the application print in the construction. The currently used 3D printing cement material has some disadvantages, which are mainly shown in: the early strength is low: the setting time is long, the material mobility is poor, difficult viscidity shortcoming such as gathers leads to the printing material to take place easily after the position collapse, warp scheduling problem, and cement hydration later stage, because the shrinkage crack that causes is contracted to the hardened cement thick liquids volume, influences 3D and prints the volume stability and the durability of component.

Disclosure of Invention

In view of the above, the present invention provides a cement-based composite paste for 3D printing to solve the above problems.

In order to achieve the purpose, the invention adopts the following technical scheme:

the cement-based composite slurry for 3D printing comprises the following raw materials in parts by weight: 30-50 parts of portland cement, 8-12 parts of Baozhu sand, 6-8 parts of modified zirconia ceramic whisker, 4-6 parts of modified boron carbide ceramic whisker, 10-20 parts of polyurethane modified epoxy resin emulsion, 0.2-0.4 part of sodium lignosulfonate, 1-2 parts of polysilazane and 20-40 parts of deionized water.

Further, the modified zirconia ceramic whisker comprises the following raw materials in parts by weight: 20-40 parts of zirconia ceramic whisker, 5-10 parts of vinyltriethoxysilane, and 100-200 parts of anhydrous ethanol.

Further, the average diameter of the zirconia ceramic whisker is 40-80 μm.

Further, the preparation steps of the modified zirconia ceramic whisker are as follows:

adding the zirconia ceramic whisker and the vinyltriethoxysilane into absolute ethyl alcohol, placing the mixture into an ultrasonic dispersion machine for ultrasonic treatment for 30-40min, filtering and drying to obtain the modified zirconia ceramic whisker.

Further, the ultrasonic treatment conditions are frequency of 20-40kHz and power of 400-600W.

Further, the modified boron carbide ceramic whisker comprises the following raw materials in parts by weight: 10-20 parts of boron carbide ceramic whiskers, 5-10 parts of ethyl orthosilicate, 20-40 parts of ammonia water with the mass fraction of 10% and 40-60 parts of absolute ethyl alcohol.

Further, the average diameter of the boron carbide ceramic whisker is 40-60 μm.

Further, the preparation steps of the modified boron carbide ceramic whisker are as follows:

(1) adding boron carbide ceramic whiskers into absolute ethyl alcohol, and performing ultrasonic dispersion for 20-30min at normal temperature to obtain a dispersion liquid;

(2) adding ammonia water into the dispersion liquid, introducing nitrogen for protection, slowly dropwise adding ethyl orthosilicate, stirring and reacting for 1-2h under the water bath condition of 40-60 ℃ at the rotating speed of 400-600r/min, centrifugally separating, washing the solid with absolute ethyl alcohol for 3-5 times, and drying in vacuum to obtain the modified boron carbide ceramic whisker.

Further, the ultrasonic dispersion conditions in the step (2) are 20-30kHz and 400W of power.

Further, the preparation method of the cement-based composite slurry for 3D printing comprises the following steps:

(1) adding the polyurethane modified epoxy resin emulsion and polysilazane into water, stirring and mixing to obtain mixed emulsion;

(2) and adding the Portland cement, the Baozhu sand, the modified zirconia ceramic whisker, the modified boron carbide ceramic whisker and the sodium lignosulfonate into the mixed emulsion, and stirring and mixing to obtain the cement-based composite slurry for 3D printing.

The invention has the beneficial effects that:

(1) the cement-based composite slurry for 3D printing adopts vinyl triethoxysilane to modify the surface of the zirconia ceramic whisker, the silane can coat the zirconia ceramic whisker, so that the zirconia ceramic whiskers can be uniformly dispersed into the cement-based composite slurry for 3D printing to ensure that the zirconia ceramic whiskers are stably dispersed, and the vinyltriethoxysilane can be attached to the surface of the zirconia ceramic whisker to coat the zirconia ceramic whisker, so that the surface energy of the zirconia ceramic whisker is reduced, the zirconia ceramic whisker is in a stable state, the agglomeration of the zirconia ceramic whisker is prevented, the compatibility of the zirconia ceramic whisker in the cement-based composite slurry for 3D printing is improved, thereby improving the toughness of the cement-based composite slurry for 3D printing, and the highly oriented structure of the whisker ensures that the portland cement has high strength performance and can effectively enhance the anti-cracking performance of the portland cement.

The cement-based composite slurry for 3D printing adopts modified boron carbide ceramic whiskers as a reinforcing framework in the slurry, simultaneously modifies the boron carbide ceramic whiskers by tetraethoxysilane, wherein tetraethoxysilane is hydrolyzed in water to generate silicon dioxide, the tetraethoxysilane can form a stable net-shaped cross-linked silicon dioxide layer on the particle surfaces of the boron carbide ceramic whiskers by hydrolysis, the dispersity of the boron carbide ceramic whiskers can be effectively improved, the boron carbide ceramic whiskers are prevented from being aggregated, the stability of the boron carbide ceramic whiskers and the compatibility of the boron carbide ceramic whiskers in the slurry are enhanced, meanwhile, the boron carbide ceramic whiskers and epoxy resin matrix molecular chains in the slurry are connected together through the action of a silicon dioxide interface layer, a three-dimensional net-shaped structure can be formed, the nano particles play a role of physical cross-linking points, and the modified nano particles play a role of stress centralizers when the silicate cement is subjected to tensile stress, and the stress applied can be effectively transferred, the cross-linking points can play a role of uniformly distributing the stress, the overall damage is reduced, and the toughness and the cracking resistance of the portland cement are further improved.

Detailed Description

The following examples are given to further illustrate the embodiments of the present invention. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The composite material comprises the following raw materials in parts by weight: 20-40 parts of zirconia ceramic whisker with the average diameter of 40-80 mu m, 5-10 parts of vinyltriethoxysilane and 100-200 parts of absolute ethyl alcohol.

Adding the zirconia ceramic whisker and the vinyltriethoxysilane into absolute ethanol, placing the mixture into an ultrasonic dispersion machine, carrying out ultrasonic treatment for 30-40min under the conditions of the frequency of 20-40kHz and the power of 400-600W, filtering and drying to obtain the modified zirconia ceramic whisker.

And respectively weighing 10-20 parts by weight of boron carbide ceramic whiskers with the average diameter of 40-60 mu m, 5-10 parts by weight of ethyl orthosilicate, 20-40 parts by weight of ammonia water with the mass fraction of 10% and 40-60 parts by weight of absolute ethyl alcohol.

Adding the boron carbide ceramic whiskers into absolute ethyl alcohol, and ultrasonically dispersing for 20-30min at normal temperature under the conditions of frequency of 20-30kHz and power of 300-;

(1) adding ammonia water into the dispersion liquid, introducing nitrogen for protection, slowly dropwise adding ethyl orthosilicate, stirring and reacting for 1-2h under the water bath condition of 40-60 ℃ at the rotating speed of 400-600r/min, centrifugally separating, washing the solid with absolute ethyl alcohol for 3-5 times, and drying in vacuum to obtain the modified boron carbide ceramic whisker.

Respectively weighing 30-50 parts of portland cement, 8-12 parts of Baozhu sand, 6-8 parts of modified zirconia ceramic whisker, 4-6 parts of modified boron carbide ceramic whisker, 10-20 parts of polyurethane modified epoxy resin emulsion, 0.2-0.4 part of sodium lignosulfonate, 1-2 parts of polysilazane and 20-40 parts of deionized water according to parts by weight;

(2) adding the polyurethane modified epoxy resin emulsion and polysilazane into water, stirring and mixing to obtain mixed emulsion;

(3) and adding the Portland cement, the Baozhu sand, the modified zirconia ceramic whisker, the modified boron carbide ceramic whisker and the sodium lignosulfonate into the mixed emulsion, and stirring and mixing to obtain the cement-based composite slurry for 3D printing.

Example 1

(1) The composite material comprises the following raw materials in parts by weight: 20-40 parts of zirconia ceramic whisker with the average diameter of 40-80 mu m, 5-10 parts of vinyltriethoxysilane and 100-200 parts of absolute ethyl alcohol.

Adding the zirconia ceramic whisker and the vinyltriethoxysilane into absolute ethanol, placing the mixture into an ultrasonic dispersion machine, carrying out ultrasonic treatment for 30-40min under the conditions of the frequency of 20-40kHz and the power of 400-600W, filtering and drying to obtain the modified zirconia ceramic whisker.

And respectively weighing 10-20 parts by weight of boron carbide ceramic whiskers with the average diameter of 40-60 mu m, 5-10 parts by weight of ethyl orthosilicate, 20-40 parts by weight of ammonia water with the mass fraction of 10% and 40-60 parts by weight of absolute ethyl alcohol.

Adding the boron carbide ceramic whiskers into absolute ethyl alcohol, and ultrasonically dispersing for 20-30min at normal temperature under the conditions of frequency of 20-30kHz and power of 300-;

(2) adding ammonia water into the dispersion liquid, introducing nitrogen for protection, slowly dropwise adding ethyl orthosilicate, stirring and reacting for 1-2h under the water bath condition of 40-60 ℃ at the rotating speed of 400-600r/min, centrifugally separating, washing the solid with absolute ethyl alcohol for 3-5 times, and drying in vacuum to obtain the modified boron carbide ceramic whisker.

Respectively weighing 30-50 parts of portland cement, 8-12 parts of Baozhu sand, 6-8 parts of modified zirconia ceramic whisker, 4-6 parts of modified boron carbide ceramic whisker, 10-20 parts of polyurethane modified epoxy resin emulsion, 0.2-0.4 part of sodium lignosulfonate, 1-2 parts of polysilazane and 20-40 parts of deionized water according to parts by weight;

(3) adding the polyurethane modified epoxy resin emulsion and polysilazane into water, stirring and mixing to obtain mixed emulsion;

(4) and adding the Portland cement, the Baozhu sand, the modified zirconia ceramic whisker, the modified boron carbide ceramic whisker and the sodium lignosulfonate into the mixed emulsion, and stirring and mixing to obtain the cement-based composite slurry for 3D printing.

Example 2

(1) The composite material comprises the following raw materials in parts by weight: 20-40 parts of zirconia ceramic whisker with the average diameter of 40-80 mu m, 5-10 parts of vinyltriethoxysilane and 100-200 parts of absolute ethyl alcohol.

Adding the zirconia ceramic whisker and the vinyltriethoxysilane into absolute ethanol, placing the mixture into an ultrasonic dispersion machine, carrying out ultrasonic treatment for 30-40min under the conditions of the frequency of 20-40kHz and the power of 400-600W, filtering and drying to obtain the modified zirconia ceramic whisker.

And respectively weighing 10-20 parts by weight of boron carbide ceramic whiskers with the average diameter of 40-60 mu m, 5-10 parts by weight of ethyl orthosilicate, 20-40 parts by weight of ammonia water with the mass fraction of 10% and 40-60 parts by weight of absolute ethyl alcohol.

Adding the boron carbide ceramic whiskers into absolute ethyl alcohol, and ultrasonically dispersing for 20-30min at normal temperature under the conditions of frequency of 20-30kHz and power of 300-;

(2) adding ammonia water into the dispersion liquid, introducing nitrogen for protection, slowly dropwise adding ethyl orthosilicate, stirring and reacting for 1-2h under the water bath condition of 40-60 ℃ at the rotating speed of 400-600r/min, centrifugally separating, washing the solid with absolute ethyl alcohol for 3-5 times, and drying in vacuum to obtain the modified boron carbide ceramic whisker.

Respectively weighing 30-50 parts of portland cement, 8-12 parts of Baozhu sand, 6-8 parts of modified zirconia ceramic whisker, 4-6 parts of modified boron carbide ceramic whisker, 10-20 parts of polyurethane modified epoxy resin emulsion, 0.2-0.4 part of sodium lignosulfonate, 1-2 parts of polysilazane and 20-40 parts of deionized water according to parts by weight;

(3) adding the polyurethane modified epoxy resin emulsion and polysilazane into water, stirring and mixing to obtain mixed emulsion;

(4) and adding the Portland cement, the Baozhu sand, the modified zirconia ceramic whisker, the modified boron carbide ceramic whisker and the sodium lignosulfonate into the mixed emulsion, and stirring and mixing to obtain the cement-based composite slurry for 3D printing.

Example 3

(1) The composite material comprises the following raw materials in parts by weight: 20-40 parts of zirconia ceramic whisker with the average diameter of 40-80 mu m, 5-10 parts of vinyltriethoxysilane and 100-200 parts of absolute ethyl alcohol.

Adding the zirconia ceramic whisker and the vinyltriethoxysilane into absolute ethanol, placing the mixture into an ultrasonic dispersion machine, carrying out ultrasonic treatment for 30-40min under the conditions of the frequency of 20-40kHz and the power of 400-600W, filtering and drying to obtain the modified zirconia ceramic whisker.

And respectively weighing 10-20 parts by weight of boron carbide ceramic whiskers with the average diameter of 40-60 mu m, 5-10 parts by weight of ethyl orthosilicate, 20-40 parts by weight of ammonia water with the mass fraction of 10% and 40-60 parts by weight of absolute ethyl alcohol.

Adding the boron carbide ceramic whiskers into absolute ethyl alcohol, and ultrasonically dispersing for 20-30min at normal temperature under the conditions of frequency of 20-30kHz and power of 300-;

(2) adding ammonia water into the dispersion liquid, introducing nitrogen for protection, slowly dropwise adding ethyl orthosilicate, stirring and reacting for 1-2h under the water bath condition of 40-60 ℃ at the rotating speed of 400-600r/min, centrifugally separating, washing the solid with absolute ethyl alcohol for 3-5 times, and drying in vacuum to obtain the modified boron carbide ceramic whisker.

Respectively weighing 30-50 parts of portland cement, 8-12 parts of Baozhu sand, 6-8 parts of modified zirconia ceramic whisker, 4-6 parts of modified boron carbide ceramic whisker, 10-20 parts of polyurethane modified epoxy resin emulsion, 0.2-0.4 part of sodium lignosulfonate, 1-2 parts of polysilazane and 20-40 parts of deionized water according to parts by weight;

(3) adding the polyurethane modified epoxy resin emulsion and polysilazane into water, stirring and mixing to obtain mixed emulsion;

(4) and adding the Portland cement, the Baozhu sand, the modified zirconia ceramic whisker, the modified boron carbide ceramic whisker and the sodium lignosulfonate into the mixed emulsion, and stirring and mixing to obtain the cement-based composite slurry for 3D printing.

Example 4

In example 4, the modified zirconia ceramic whisker of the present invention was replaced with a zirconia ceramic whisker under the same conditions and in the same component ratio as in example 1.

Example 5

In example 5, the boron carbide ceramic whisker is used instead of the modified boron carbide ceramic whisker of the invention, and the other conditions and the component ratio are the same as those in example 1.

Experimental example:

the cement-based composite pastes for 3D printing prepared in examples 1 to 5 were subjected to a performance test.

The results of the experiment are as follows:

table 1: experimental comparison of slurries of examples 1-5 with slurry preparation samples of comparative examples

Item	Example 1	Example 2	Example 3	Example 4	Example 5
						Compressive strength MPa/3d	58.52	58.65	58.49	31.38	38.75
Compressive strength MPa/28d	65.28	65.45	65.22	58.12	56.23
						Flexural strength MPa/3d	7.82	7.86	7.84	5.11	5.25
Flexural strength MPa/28d	8.55	8.57	8.56	6.22	6.17
						Self-flow value mm	235	235	235	230	230

The performance of the examples 1 to 3 is compared, wherein the performance data of the example 2 is the most excellent, because the ratio of the added materials in the example 2 is the best, and the difference of the performance data of the examples 1 to 3 is smaller, which also reflects that the technical scheme of the application can be implemented from the side.

Comparing the performances of the example 1 and the example 4, since the zirconia ceramic whisker is used for replacing the modified zirconia ceramic whisker of the invention in the example 4, and other conditions and component proportions are the same as those in the example 1, the compressive strength and the flexural strength of the final portland cement are both significantly reduced, so that the zirconia ceramic whisker in the example 4 is agglomerated in the cement-based composite slurry for 3D printing to cause the mechanical property of the portland cement to be reduced, the cement-based composite slurry for 3D printing in the example 1 adopts vinyltriethoxysilane to perform surface modification on the zirconia ceramic whisker, the silane coats the zirconia ceramic whisker, so that the zirconia ceramic whisker can be uniformly dispersed in the cement-based composite slurry for 3D printing to be stably dispersed, and the vinyltriethoxysilane can be attached to the surface of the zirconia ceramic whisker to coat the zirconia ceramic whisker, the surface energy of the zirconia ceramic whisker is reduced, the zirconia ceramic whisker is in a stable state, the agglomeration of the zirconia ceramic whisker is prevented, and the compatibility of the zirconia ceramic whisker in the cement-based composite slurry for 3D printing is improved, so that the toughness of the cement-based composite slurry for 3D printing is improved, and the high-orientation structure of the whisker ensures that the Portland cement has high strength performance and can effectively enhance the anti-cracking performance of the Portland cement;

comparing the performances of example 1 and example 5, since the boron carbide ceramic whisker is used in example 5 instead of the modified boron carbide ceramic whisker of the invention, and other conditions and component proportions are the same as those in example 1, the compressive strength and the flexural strength of the final portland cement are both significantly reduced, thus it can be seen that the boron carbide ceramic whisker in example 5 is unevenly dispersed in the portland cement, resulting in the reduction of both the compressive strength and the flexural strength of the portland cement, the cement-based composite slurry for 3D printing of example 1 adopts the modified boron carbide ceramic whisker as a reinforcing skeleton in the slurry, and simultaneously modifies the boron carbide ceramic whisker with tetraethoxysilane, which is hydrolyzed in water to generate silica, and the hydrolysis of the tetraethoxysilane can form a stable network cross-linked silica layer on the particle surface of the boron carbide ceramic whisker, meanwhile, the boron carbide ceramic whisker and an epoxy resin matrix molecular chain in the slurry are connected together through the action of a silicon dioxide interface layer to form a three-dimensional network structure, the nano particles play a role of physical cross-linking points, and when the portland cement is under the action of tensile stress, the modified nano particles play a role of stress concentrators and can effectively transfer the applied stress, the cross-linking points can play a role of uniformly distributing the stress, the overall damage is reduced, and the toughness and the cracking resistance of the portland cement are further improved.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.