Polymer emulsion slurry for 3D printing of concrete as well as preparation method and application of polymer emulsion slurry

Abstract

The invention relates to polymer emulsion slurry for 3D printing of concrete as well as a preparation method and application of the polymer emulsion slurry. The polymer emulsion slurry for concrete 3D printing is prepared from the following components in percentage by mass: 48 to 75 percent of water-based emulsion, 10 to 30 percent of response material, 5 to 15 percent of stabilizer, 1 to 5 percent of solubilizer and 5 to 27 percent of water, wherein the response material is selected from at least one of iron powder, aluminum powder and tin powder; the particle size of the response material is less than 10 microns. The technical problem to be solved by the invention is how to provide the polymer emulsion slurry for concrete 3D printing, so that the bonding force between layers and between reinforcing steel bars and a concrete matrix of a 3D concrete product printed by using the polymer emulsion slurry is high, and meanwhile, the constructability and appearance of 3D printed concrete are not influenced, so that the polymer emulsion slurry is more suitable for application.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete 3D printing, and in particular relates to a polymer emulsion slurry for concrete 3D printing, and a preparation method and application thereof. Background Art

[0002] 3D printing is a process of printing materials layer by layer, stacking the layers, and finally forming a three-dimensional printed product. In recent years, extruded 3D printed concrete has been successfully applied to civil engineering, receiving widespread attention and great development potential. However, there are also many problems in the application of 3D printed concrete, among which the weak bonding performance between concrete layers is manifested as low tensile strength of 3D printed concrete products. This is one of the most prominent problems in the application of 3D printed concrete, which seriously restricts the promotion and application of 3D printed concrete.

[0003] In the prior art, in order to improve the interlayer bonding strength of 3D printed concrete, some studies have reported that the above-mentioned problems are solved by methods of planting steel bars and applying interface agents. However, both the methods of planting steel bars and applying interface agents have defects. Specifically, the process of planting steel bars is relatively complicated during the application process and is difficult to promote. Existing interface agents, such as polyacrylic acid emulsions, can improve the interfacial bonding strength of 3D printed concrete to a certain extent, but the degree of improvement in the tensile strength of 3D printed concrete products is very limited, far from meeting the actual application requirements. Therefore, it is urgent to develop a material that can better improve the interfacial bonding strength of 3D printed concrete and better maintain the constructibility and appearance of 3D printed concrete, so as to facilitate the promotion and application of 3D printed concrete. Summary of the invention

[0004] The main purpose of the present invention is to provide a polymer emulsion slurry for concrete 3D printing and a preparation method and application thereof. The technical problem to be solved is how to prepare a polymer emulsion slurry for concrete 3D printing so that the interfacial bonding strength of the 3D concrete products printed by the slurry is high, while not affecting the constructability and appearance of the 3D printed concrete, so that it is more suitable for application.

[0005] The purpose of the present invention and the technical problem solved are achieved by adopting the following technical solutions. According to the polymer emulsion slurry for concrete 3D printing proposed by the present invention, it includes, by mass percentage: 48% to 75% of aqueous emulsion, 10% to 30% of response material, 5% to 15% of stabilizer, 1% to 5% of solubilizer and 5% to 27% of water; wherein the response material is selected from at least one of iron powder, aluminum powder and tin powder; the particle size of the response material is less than 10 μm.

[0006] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0007] Preferably, in the aforementioned polymer emulsion slurry for concrete 3D printing, the iron powder is selected from at least one of hydroxyl iron powder, carbon-based iron powder, carbonyl iron powder, nano iron powder and nano Fe3O4.

[0008] Preferably, in the aforementioned polymer emulsion slurry for concrete 3D printing, the response material comprises a first response material and a second response material; the first response material can vibrate under the action of a high-frequency magnetic field; and the second response material can absorb energy under microwave excitation.

[0009] Preferably, in the aforementioned polymer emulsion slurry for concrete 3D printing, the first response material is selected from at least one of hydroxyl iron powder, carbon-based iron powder, carbonyl iron powder, nano iron powder and nano Fe3O4; the second response material is selected from aluminum powder and / or tin powder; the mass ratio of the first response material to the second response material is 1:0.5 to 10.

[0010] Preferably, in the aforementioned polymer emulsion slurry for concrete 3D printing, the aqueous emulsion is selected from at least one of polystyrene emulsion, polyaniline emulsion, styrene-butadiene emulsion and polyacrylic acid emulsion.

[0011] Preferably, in the aforementioned polymer emulsion slurry for concrete 3D printing, the stabilizer is selected from at least one of nano-SiO2 particles, graphene nanosheets and carbon nanotubes.

[0012] Preferably, in the aforementioned polymer emulsion slurry for concrete 3D printing, the solubilizing agent is CSH gel with a particle size of less than 0.5 μm.

[0013] Preferably, the aforementioned polymer emulsion slurry for concrete 3D printing further comprises 0.5% to 2% of a heat storage agent; the heat storage agent is at least one of aliphatic hydrocarbons and fatty acid particles.

[0014] The purpose of the present invention and the solution to the technical problem are also achieved by the following technical solutions. According to the present invention, a method for preparing a polymer emulsion slurry for concrete 3D printing comprises the following steps:

[0015] 1) weighing raw materials according to the formula; in terms of mass percentage, the polymer emulsion slurry comprises: 48% to 75% aqueous emulsion, 10% to 30% response material, 5% to 15% stabilizer, 1% to 5% solubilizer and 5% to 27% water;

[0016] 2) Mixing the aqueous emulsion and water, adding the response material, stabilizer and solubilizer to the mixture at a stirring speed of >10000 rpm, and stirring evenly to obtain a polymer emulsion slurry for concrete 3D printing; wherein the response material is selected from at least one of iron powder, aluminum powder and tin powder; and the particle size of the response material is <10 μm.

[0017] The purpose of the present invention and the technical problem solved by the present invention are also achieved by the following technical solutions: According to the present invention, a polymer emulsion slurry for concrete 3D printing is used in concrete 3D printing.

[0018] By means of the above technical solution, the polymer emulsion slurry for concrete 3D printing and its preparation method and application proposed in the present invention have at least the following advantages:

[0019] The present invention proposes a polymer emulsion slurry for concrete 3D printing and a preparation method and application thereof. At least one material selected from iron powder, aluminum powder and tin powder is introduced into the polymer emulsion slurry as a response material, so that they can absorb energy under the action of an external energy field, such as vibrating under the action of a high-frequency magnetic field and / or absorbing energy and generating heat under microwave excitation. A large number of studies have shown that due to the construction process of extruded 3D printed concrete, the porosity between the interfaces of concrete layers and between the steel bars and concrete is significantly higher than that of the matrix during the printing process, which may lead to a decrease in the bonding strength between the concrete layers and between the steel bars and the concrete matrix, thereby resulting in a weak bonding strength between the 3D printed concrete layers and a decrease in the overall performance. The technical solution of the present invention provides a polymer emulsion slurry for concrete 3D printing, which is arranged between each printing layer of the 3D printed concrete and / or at the interface between the steel bars and the concrete matrix. On the one hand, the particle size of the response material is strictly controlled to be less than 10 μm, so that it is small enough to pass through the high-frequency magnetic field. Control its movement; then, under the action of the high-frequency magnetic field, the responsive material is vibrated at high frequency between each printed layer of the concrete, thereby vibrating and compacting the concrete between the layers and at the interface between the steel bar and the concrete matrix, and improving the bonding strength between each printed layer and between the steel bar and the concrete matrix; on the other hand, through the synergistic effect of the aqueous emulsion in the polymer emulsion slurry under vibration, the aqueous emulsion is more conducive to penetrating into the upper and lower layers of the concrete, thereby forming a polymer network that penetrates the concrete layer, thereby enhancing the bonding between the concrete layers and improving the bonding strength of the 3D printed concrete products; at the same time, by strictly controlling the particle size of the responsive material to less than 10μm, the force of the responsive material during high-frequency vibration is not too large, that is, the vibration area of ​​the responsive material is controlled in a very small micro-area where the interface between the concrete layers and the steel bar-concrete matrix interface are located, that is, the responsive material is only micro-vibrated, thereby avoiding damage to the constructability of the 3D printed concrete during vibration of the responsive material, introducing micro-vibration of the responsive material to avoid affecting the overall constructability and not causing the collapse of the 3D printed concrete. By introducing a responsive material capable of absorbing energy under microwave excitation into the polymer emulsion slurry, and by arranging the polymer emulsion slurry of the present invention between each printing layer of 3D printed concrete and at the interface between steel bars and concrete matrix, under the excitation of microwave energy, the characteristic of the responsive material absorbing radiation is utilized, and the responsive material generates heat after absorbing radiation, thereby heating and curing the concrete in the micro-region between each printing layer of the concrete, thereby uniformly improving the bonding strength between each printing layer of the 3D printed concrete and at the interface between the steel bars and concrete matrix.By setting the polymer emulsion slurry of the present invention between each printed layer of 3D concrete, the interfacial tensile bonding strength of the 3D printed concrete is greatly improved; compared with the 3D printed concrete set with the polyacrylic acid emulsion interface agent of the prior art, its interfacial tensile bonding strength is increased by more than 1.6 times; the steel bar grip strength is increased by more than 0.3 times.

[0020] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail as follows. DETAILED DESCRIPTION

[0021] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a polymer emulsion slurry for concrete 3D printing and its preparation method and application according to the present invention, its specific implementation, structure, characteristics and effects in combination with the preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0022] The present invention provides a polymer emulsion slurry for concrete 3D printing, which comprises, by mass percentage, 48% to 75% of an aqueous emulsion, 10% to 30% of a response material, 5% to 15% of a stabilizer, 1% to 5% of a solubilizer, and 5% to 27% of water.

[0023] The most critical component in the above technical solution is the response material; the preferred response material of the present invention is selected from at least one of iron powder, aluminum powder and tin powder, and its particle size is less than 10 μm. The selection of the material of the response material, on the one hand, takes into account that it can vibrate under the action of a high-frequency magnetic field to vibrate at the working surface of the 3D printed concrete where the polymer emulsion slurry of the present invention is set, and by strictly limiting the particle size of the response material to less than 10 μm, it is small enough to vibrate under the action of a high-frequency magnetic field, while at the same time making its vibration amplitude and range small, thereby avoiding the adverse effects of vibration on the constructability and appearance of the 3D printed concrete; on the other hand, it takes into account that it can absorb energy and generate heat under microwave excitation, thereby providing heating and curing for the working surface of the 3D printed concrete and improving its comprehensive performance.

[0024] The most typical application scenario of the polymer emulsion slurry of the present invention is for concrete 3D printing.

[0025] In a specific application scenario, it includes the following steps: printing concrete layers layer by layer; arranging a polymer emulsion layer formed by the polymer emulsion slurry of the present invention between two adjacent concrete layers to obtain a concrete 3D printed blank; then, placing the above-mentioned concrete 3D printed blank in external energy, so that the response material vibrates under the action of a high-frequency magnetic field and / or absorbs energy under microwave excitation, thereby fusing the concrete layer and the polymer emulsion layer into a whole under the conditions of micro-vibration and / or thermal curing of the response material.

[0026] In another specific application scenario, it includes the following steps: printing concrete layers layer by layer; arranging a polymer emulsion layer formed by the polymer emulsion slurry of the present invention between two adjacent concrete layers to obtain a concrete 3D printed blank; arranging a polymer emulsion layer formed by the polymer emulsion slurry of the present invention on the surface of the steel bar, which can be impregnated, smeared or sprayed, etc., and then drying it to obtain a steel bar with a polymer emulsion layer arranged on the surface; the drying here refers to surface drying rather than actual drying, so that it can adapt to the subsequent process of inserting the steel bar into the concrete blank and being able to vibrate after absorbing energy in an external energy field; then, the steel bar with a polymer emulsion layer arranged on the surface is inserted into the above-mentioned concrete 3D printed blank in a direction perpendicular to the concrete printing surface; finally, the above-mentioned concrete 3D printed blank is placed in external energy, so that the response material vibrates under the action of the high-frequency magnetic field and / or absorbs energy under microwave excitation, so that the concrete layer and the polymer emulsion layer are fused into a whole under the micro-vibration and / or thermal curing conditions of the response material.

[0027] The polymer emulsion slurry of the present invention is applied to the above process and is arranged between each printing layer of 3D printed concrete and at the steel bar-concrete interface to improve the bonding strength between each printing layer and the steel bar-concrete matrix interface, thereby improving the interface tensile bonding strength and steel bar gripping strength of the 3D printed concrete product.

[0028] In the above technical scheme, introducing a response material into the polymer emulsion slurry is the key to achieving the technical effect of the present invention; the response material can be a material that can vibrate under the action of a high-frequency magnetic field, that is, a first response material; it can also be a material that can absorb energy under microwave excitation, that is, a second response material; introducing the first response material alone into the polymer emulsion slurry can achieve the effect of improving the interlayer bonding force of the present invention; introducing the second response material alone into the polymer emulsion slurry can also achieve the effect of improving the interlayer bonding force of the present invention; more preferably, the polymer emulsion slurry includes both a first response material that can vibrate under the action of a high-frequency magnetic field and a second response material that can absorb energy under microwave excitation, and under the joint action of the two, further technical effects can be achieved; in order to optimize the bonding strength of each printed layer of 3D printed concrete, the present invention preferably has a mass ratio of the first response material to the second response material of 1:0.5 to 10.

[0029] In the above technical solution, the particle size of the response material needs to be strictly controlled to be less than 10μm. The main reasons for strictly limiting the particle size of the response material are: first, to avoid the high-frequency magnetic field from being difficult to control its movement due to the response material being too large, that is, the response material cannot respond, and thus cannot be vibrated between layers or at the interface between the steel bar and the concrete matrix, and cannot achieve its technical effect in 3D printed concrete; second, to avoid the response material being too large and causing its vibration area to be large, that is, to control the response material to vibrate only in micro-areas between each printed layer of concrete and at the interface between the steel bar and the concrete matrix, so as to avoid a greater impact on the upper and lower layers of the concrete printing layer, and avoid affecting the overall constructability of the 3D printed concrete and causing the collapse of the 3D printed concrete; in view of the above two considerations, for the comprehensive performance of the balancer, the present invention preferably has a particle size of the response material less than 10μm.

[0030] By arranging the polymer emulsion slurry of the present invention between the printed layers of 3D printed concrete and at the interface between the steel bar and the concrete matrix, the response material is vibrated at high frequency between the printed layers of the concrete and at the interface between the steel bar and the concrete matrix under the action of the high-frequency magnetic field, thereby compacting the concrete between the layers and at the interface between the steel bar and the concrete matrix, and improving the bonding strength between the printed layers and the steel bar and the concrete interface; by arranging the polymer emulsion slurry of the present invention between the printed layers of 3D printed concrete and at the interface between the steel bar and the concrete matrix, the response material absorbs radiation under the excitation of microwave energy, thereby heating and curing the concrete in the micro-region between the printed layers of the concrete and at the interface between the steel bar and the concrete matrix, thereby uniformly improving the interface bonding strength of the 3D printed concrete.

[0031] In the above technical solution, iron powder is the first response material, which mainly vibrates under the action of high-frequency magnetic field to generate micro-area vibration between each printed layer of concrete to improve its bonding strength; aluminum powder and / or tin powder is the second response material, which mainly utilizes its energy storage characteristics to absorb and release the energy of electromagnetic waves, thereby forming heat-curing micro-areas between each printed layer of concrete to improve the interlayer bonding strength.

[0032] In order to make the responsive material have good compatibility with cement-based materials so as to achieve good micro-region vibration, for example, hydroxyl can improve the hydrophilicity of the responsive material, carbonyl can further enhance its response to the external magnetic field, and carbonyl can improve its dispersibility in the aqueous emulsion, the present invention preferably selects the iron powder from at least one of hydroxyl iron powder, carbon-based iron powder, carbonyl iron powder, nano iron powder and nano Fe3O4. The particle size of the nano iron powder and nano Fe3O4 is preferably <50nm.

[0033] The aqueous emulsion in the above technical solution exists mainly as a carrier of the response material. Due to the characteristics of the technical solution of the present invention, the particle size of the response material used in the present invention is determined to be less than 10μm, and the response material with a very small particle size is easy to agglomerate, so that the pure response material is evenly distributed on the surface of each printed layer of the 3D concrete. The technical solution of the present invention preferably disperses the response material in the aqueous emulsion so that the response material can be better dispersed so that it can be evenly arranged on the surface of each printed layer of the 3D concrete and evenly arranged on the surface of the steel bar; the aqueous emulsion can be selected from any form of emulsion that can load and disperse the response material.

[0034] In order to make it have better affinity with cement materials, the technical solution of the present invention preferably uses an aqueous emulsion; the aqueous emulsion is selected from at least one of polystyrene emulsion, polyaniline emulsion, styrene-butadiene emulsion and polyacrylic acid emulsion.

[0035] The aqueous emulsion in the above technical solution also plays a certain role in improving the bonding force between the printed layers of 3D printed concrete. The present invention introduces an aqueous emulsion into the polymer emulsion slurry. In addition to being used as a carrier to disperse the response material, the aqueous emulsion can also penetrate into the upper and lower layers of the concrete printing layer under the synergistic effect of vibration / heat curing, thereby forming a polymer network that penetrates the concrete layer, thereby enhancing the bonding force between the concrete layers and improving the bonding strength of the 3D printed concrete products.

[0036] In the above technical solution, a stabilizer is further added, and the stabilizer is preferably at least one of nano-SiO2 particles, graphene nanosheets and carbon nanotubes. The stabilizer is mainly used to fill the gap between the micron-scale and nano-scale response materials, enhance Brownian motion, and prevent the polymer emulsion slurry from segregating, thereby improving the stability of the polymer emulsion slurry.

[0037] Furthermore, the technical solution of the present invention also includes 1% to 5% of a solubilizer; the solubilizer is a CSH gel with a particle size of less than 0.5 μm. When the solubilizer is added to the polymer emulsion slurry, the total content of water can be appropriately reduced so that the total content of the solubilizer and water is 7% to 27%.

[0038] CSH gel is a hydrated calcium silicate gel, which is generally filled between cement hydration products, greatly improving the structural density, thereby improving its strength. The technical solution of the present invention is to add it into the polymer emulsion slurry, which is different from the role of nano-CSH in promoting hydration in cement materials. CSH gel in the present invention mainly utilizes the special layered structure of nano-CSH to enable it to provide attachment points for the response material, further improving the solubility and stability of the response material in the aqueous emulsion, thereby further improving its performance.

[0039] Furthermore, the technical solution of the present invention preferably also includes 0.5% to 2% of a heat storage agent; the heat storage agent is at least one of aliphatic hydrocarbons and fatty acid particles.

[0040] In the above technical scheme, the fatty acid and the aliphatic hydrocarbon are not specifically limited; optionally, the fatty acid can be stearic acid (octadecanoic acid), pearl fatty acid (heptadecanoic acid) and palmitic acid, etc.; the aliphatic hydrocarbon can be n-octadecane, n-eicosane, etc. The polymer emulsion slurry of the present invention adds a heat storage agent, which mainly utilizes the energy storage characteristics of aliphatic hydrocarbons and fatty acid materials to absorb the energy generated by cement hydration, slow down the hydration rate of cement in the concrete between each concrete printing layer and at the interface between the steel bar and the concrete matrix, thereby reducing the concrete yield stress increase rate / hardening rate at the interface, reducing the resistance faced by the response material during the vibration process, thereby further improving the vibration effect.

[0041] The present invention also proposes a method for preparing a polymer emulsion slurry for concrete 3D printing, which comprises the following steps: 1) weighing raw materials according to a formula; in terms of mass percentage, the polymer emulsion slurry comprises: 48% to 75% aqueous emulsion, 10% to 30% response material, 5% to 15% stabilizer, 1% to 5% solubilizer and 5% to 27% water; optionally, 0.5% to 2% heat storage agent is also included; 2) mixing the aqueous emulsion and water, and then adding the response material, stabilizer and solubilizer to the mixed liquid under the condition of a stirring speed of >10000rpm, and optionally a heat storage agent is also included; stirring evenly to obtain polymer emulsion slurry for concrete 3D printing.

[0042] In the above technical solution, the dispersion of various raw materials is mainly carried out through mechanical mixing. The key point of control is to add the response material to the polymer emulsion slurry. High-speed stirring is required when adding the response material. The stirring speed is greater than 10000rpm to evenly disperse the raw materials.

[0043] The present invention also proposes an application of the aforementioned polymer emulsion slurry for concrete 3D printing in concrete 3D printing. During 3D concrete printing, a layer of concrete is first printed, and then polymer emulsion slurry is sprayed on the concrete layer; then a layer of concrete is continuously printed on the surface of the polymer emulsion slurry, and then polymer emulsion slurry is sprayed on the newly printed concrete layer; this process is repeated until the 3D printed concrete product is printed; the last layer is a concrete layer; after printing, optionally, a steel bar having a polymer emulsion layer (surface dry) on its surface is inserted into the 3D printed concrete product in a direction perpendicular to the concrete printing surface; finally, the above-mentioned 3D concrete printed product is placed as a whole in a high-frequency magnetic field and / or a microwave field, so that the response material vibrates under the action of the high-frequency magnetic field and / or absorbs energy under microwave excitation, so that the response material performs micro-area vibration and / or absorbs radiation between each 3D printed concrete layer, thereby heating and curing each concrete layer, thereby improving the interlayer bonding strength of the 3D printed concrete; compared with the 3D printed concrete provided with the acrylic emulsion interface agent of the prior art, its interface tensile bonding strength is increased by more than 1.6 times; and the steel bar gripping strength is increased by more than 0.3 times.

[0044] Generally, the initial setting time of 3D concrete is about 2 hours, and the final setting time is 4 to 5 hours; generally, micro-vibration should be carried out within the initial setting time. In order to ensure the technical effect, it is preferred that the direction of application of the magnetic field and / or electromagnetic wave is perpendicular to the surface of the concrete layer, so that the response material can be micro-vibrated between the concrete layers; the movement direction of the response material can be vertical, oblique, or horizontal. In the above technical scheme, the magnetic field intensity is preferably 1 to 1000KA / m, the magnetic field frequency is preferably 50 to 200Hz; the electromagnetic wave frequency is preferably 300MHz to 10GHz, and the duration of applying the external energy is preferably 5 to 20min.

[0045] The present invention will be further described below in conjunction with specific embodiments, but this should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by technicians in this field based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention.

[0046] Unless otherwise specified, the materials, reagents, etc. involved below are all commercially available products well known to those skilled in the art; unless otherwise specified, the methods described are all methods well known in the art. Unless otherwise defined, the technical terms or scientific terms used should have the common meanings understood by ordinary technicians in the field to which the present invention belongs.

[0047] In the embodiments of the present invention, the test was performed in accordance with the "3D Printing Concrete Basic Mechanical Properties Test Method" T / CCPA 33-2022 (T / CBMF 183).

[0048] In the embodiments of the present invention, the test is carried out in accordance with the "Test Method for Bond Strength of Cement Concrete and Steel Bars" T0566-2020.

[0049] The solid contents of the aqueous emulsions used in the following embodiments are as follows: the solid content of the polystyrene emulsion is 50%, the solid content of the styrene-butadiene emulsion is 48%, and the solid content of the polyacrylic acid emulsion is 55%, all of which are purchased commercially; the 3D printing concrete is also purchased commercially.

[0050] Example 1

[0051] The polymer emulsion slurry preparation method of this embodiment is as follows:

[0052] 1) Weigh the raw materials according to the formula; in terms of mass percentage, the polymer emulsion slurry includes: the response material includes hydroxyl iron powder, carbonyl iron powder and nano iron powder with a particle size of less than 10 μm, the mass ratio of the three is 2:3:5, and the response material accounts for 18% of the total weight of the polymer emulsion slurry; the aqueous emulsion includes polystyrene emulsion and styrene butadiene emulsion, the mass ratio of the two is 4:6, and the aqueous emulsion accounts for 70% of the total weight of the polymer emulsion slurry; the stabilizer includes nano-SiO2 particles (particle size <0.5 μm) and graphene nanosheets (sheet diameter <10 μm, thickness <10 nm), the mass ratio of the two is 7:3, and the stabilizer accounts for 5% of the total weight of the polymer emulsion slurry; the solubilizer is CSH gel with a particle size of less than 0.25 μm, accounting for 2% of the total mass of the polymer emulsion slurry; water accounts for 5% of the total weight of the polymer emulsion slurry;

[0053] 2) Mixing the aqueous emulsion and water, adding the response material and other additives to the mixture at a stirring speed of >10000 rpm, and stirring evenly to obtain a polymer emulsion slurry for concrete 3D printing;

[0054] 3) Print a layer of concrete, and evenly spray a layer of polymer emulsion slurry on its surface, with the spraying amount being 0.8% of the mass of the cementitious material of the layer; print another layer of concrete (material and thickness are the same as before), and spray another layer of polymer emulsion slurry (spraying amount is the same as before); repeat this operation until the 3D printed concrete product is printed; the last layer is a concrete layer; it contains four layers of concrete and three layers of polymer emulsion;

[0055] 4) After printing is completed, turn on the magnetic field generator, place the printed component in the magnetic field, and magnetize the 3D printed concrete component sprayed with polymer emulsion slurry. The magnetic field intensity is 450KA / m, the magnetization time is 10 minutes, and the frequency of changing the magnetic field direction is 100 Hz.

[0056] After testing, the tensile bonding strength of the concrete interface printed in this embodiment is 5.8 MPa.

[0057] Comparative Example 1

[0058] The same as Example 1, except that the interface agent used is a commercially purchased polyacrylic acid emulsion.

[0059] After testing, the tensile bonding strength of the concrete interface of this comparative example is 2.11 MPa; compared with comparative example 1, the tensile bonding strength of the concrete interface of embodiment 1 is increased by 175%.

[0060] Example 2

[0061] The polymer emulsion slurry preparation method of this embodiment is as follows:

[0062] 1) Weighing raw materials according to the formula of polymer emulsion slurry; in terms of mass percentage, the polymer emulsion slurry includes: the response material includes hydroxyl iron powder, carbonyl iron powder and nano iron powder with a particle size of less than 10 μm, the mass ratio of the three is 3:5:2, and the response material accounts for 28% of the total weight of the polymer emulsion slurry; the aqueous emulsion includes polystyrene emulsion, styrene butadiene emulsion and polyacrylic acid emulsion, the mass ratio of the three is 2:2:6, and the aqueous emulsion accounts for 55% of the total weight of the polymer emulsion slurry; the stabilizer includes nano-SiO2 particles (particle size <0.5 μm) and graphene nanosheets (sheet diameter <10 μm, thickness <10 nm), the mass ratio of the two is 7:3, and the stabilizer accounts for 7% of the total weight of the polymer emulsion slurry; the solubilizer is CSH gel with a particle size of less than 0.5 μm, accounting for 1.5% of the total mass of the polymer emulsion slurry, and water accounts for 8.5% of the total weight of the polymer emulsion slurry;

[0063] 2) Mixing the aqueous emulsion and water, adding the response material and the additive to the mixture at a stirring speed of >10000 rpm, and stirring evenly to obtain a polymer emulsion slurry for concrete 3D printing;

[0064] 3) Print a layer of concrete, and evenly spray a layer of polymer emulsion slurry on its surface, with the spraying amount being 1.5% of the mass of the cementitious material of the layer; print another layer of concrete (material and thickness are the same as before), and spray another layer of polymer emulsion slurry (spraying amount is the same as before); repeat this operation until the 3D printed concrete product is printed; the last layer is a concrete layer; it contains four layers of concrete and three layers of polymer emulsion;

[0065] 4) After printing is completed, turn on the magnetic field generator, place the printed component in the magnetic field, and magnetize the 3D printed concrete component sprayed with polymer emulsion slurry. The magnetic field intensity is 550KA / m, the magnetization time is 15min, and the frequency of changing the magnetic field direction is 150Hz.

[0066] After testing, the concrete interface tensile bonding strength of this embodiment is 5.98 MPa.

[0067] Comparative Example 2

[0068] The same as Example 2, except that the interface agent used is a commercially purchased polyacrylic acid emulsion.

[0069] After testing, the tensile bonding strength of the concrete interface of this comparative example is 2.11 MPa; compared with comparative example 2, the tensile bonding strength of the concrete interface of embodiment 2 is increased by 183%.

[0070] Example 3

[0071] The polymer emulsion slurry preparation method of this embodiment is as follows:

[0072] 1) Weighing raw materials according to the formula of polymer emulsion slurry; in terms of mass percentage, the polymer emulsion slurry includes: the response material includes hydroxy iron powder, aluminum powder and tin powder with a particle size of less than 10 μm, the mass ratio of the three is 3:5:2, and the response material accounts for 15% of the total weight of the polymer emulsion slurry; the aqueous emulsion includes polystyrene emulsion, styrene butadiene emulsion and polyacrylic acid emulsion, the mass ratio of the three is 4:2:4, and the aqueous emulsion accounts for 65% of the total weight of the polymer emulsion slurry; the stabilizer includes nano-SiO2 particles (particle size <0.5 μm), graphene nanosheets (sheet diameter <10 μm, thickness <10 nm) and carbon nanotubes (diameter <15 nm) in a mass ratio of 4:4:2, and the stabilizer accounts for 5% of the total weight of the polymer emulsion slurry; the solubilizer is CSH gel with a particle size of less than 0.3 μm, accounting for 3.5% of the total mass of the polymer emulsion slurry, and water accounts for 11.5% of the total weight of the polymer emulsion slurry;

[0073] 2) Mixing the aqueous emulsion and water, adding the response material and the additive to the mixture at a stirring speed of >10000 rpm, and stirring evenly to obtain a polymer emulsion slurry for concrete 3D printing;

[0074] 3) Print a layer of concrete, and evenly spray a layer of polymer emulsion slurry on its surface, with the spraying amount being 1.2% of the mass of the cementitious material used in the layer of concrete; print another layer of concrete (material and thickness are the same as before), and spray another layer of polymer emulsion slurry (spraying amount is the same as before); repeat this operation until the 3D printed concrete product is printed; the last layer is a concrete layer; it contains four layers of concrete and three layers of polymer emulsion;

[0075] 4) After printing is completed, turn on the microwave generator, place the printed part in the microwave generator, and perform microwave treatment on the 3D printed concrete component sprayed with the polymer emulsion slurry. The microwave frequency of the polymer emulsion slurry is 1000KHz, and the radiation time is 15min.

[0076] After testing, the concrete interface tensile bonding strength of this embodiment is 7.9 MPa.

[0077] Comparative Example 3

[0078] The same as Example 3, except that the interface agent used is a commercially purchased polyacrylic acid emulsion.

[0079] After testing, the tensile bonding strength of the concrete interface of this comparative example is 2.75 MPa; compared with comparative example 3, the tensile bonding strength of the concrete interface of embodiment 3 is increased by 187%.

[0080] Example 4

[0081] Same as Example 1, except that the response material accounts for 10% of the total weight of the polymer emulsion slurry; the aqueous emulsion accounts for 50% of the total weight of the polymer emulsion slurry; the stabilizer accounts for 13% of the total weight of the polymer emulsion slurry; water accounts for 27% of the total weight of the polymer emulsion slurry; the print is magnetized, the magnetic field intensity is 900KA / m, the magnetization time is 15min, and the frequency of changing the magnetic field direction is 150Hz.

[0082] After testing, the concrete interface tensile bonding strength of this embodiment is 5.95 MPa.

[0083] Comparative Example 4

[0084] Same as Example 4, except that the interface agent used is a commercially purchased polyacrylic acid emulsion.

[0085] After testing, the tensile bonding strength of the concrete interface of this comparative example is 2.11 MPa; compared with comparative example 4, the tensile bonding strength of the concrete interface of embodiment 4 is increased by 182%.

[0086] Example 5

[0087] Same as Example 2, except that the response material accounts for 13% of the total weight of the polymer emulsion slurry; the aqueous emulsion accounts for 75% of the total weight of the polymer emulsion slurry; the stabilizer accounts for 5% of the total weight of the polymer emulsion slurry; and water accounts for 7% of the total weight of the polymer emulsion slurry.

[0088] After testing, the concrete interface tensile bonding strength of this embodiment is 6.15 MPa.

[0089] Comparative Example 5

[0090] Same as Example 5, except that the interface agent used is a commercially purchased polyacrylic acid emulsion.

[0091] After testing, the tensile bonding strength of the concrete interface of this comparative example is 2.11 MPa; compared with comparative example 5, the tensile bonding strength of the concrete interface of embodiment 5 is increased by 191%.

[0092] Example 6

[0093] Same as Example 3, except that the response material accounts for 30% of the total weight of the polymer emulsion slurry; the aqueous emulsion accounts for 48% of the total weight of the polymer emulsion slurry; the stabilizer accounts for 15% of the total weight of the polymer emulsion slurry; and water accounts for 7% of the total weight of the polymer emulsion slurry.

[0094] After testing, the concrete interface tensile bonding strength of this embodiment is 7.75 MPa.

[0095] Comparative Example 6

[0096] Same as Example 6, except that the interface agent used is a commercially purchased polyacrylic acid emulsion.

[0097] After testing, the tensile bonding strength of the concrete interface of this comparative example is 2.75 MPa; compared with comparative example 6, the tensile bonding strength of the concrete interface of embodiment 6 is increased by 182%.

[0098] Example 7

[0099] The same as Example 3, except that the response material includes aluminum powder and tin powder with a particle size of less than 10 μm, and the mass ratio of the two is 5:5. The microwave generator is turned on, and the printed component is placed in the microwave generator. The 3D printed concrete component sprayed with the polymer emulsion slurry is subjected to microwave treatment, and the microwave frequency is 750 KHz, and the radiation time is 10 minutes.

[0100] After testing, the concrete interface tensile bonding strength of this embodiment is 7.1 MPa.

[0101] Comparative Example 7

[0102] Same as Example 7, except that the interface agent used is a commercially purchased polyacrylic acid emulsion.

[0103] After testing, the tensile bonding strength of the concrete interface of this comparative example is 2.65 MPa; compared with comparative example 7, the tensile bonding strength of the concrete interface of embodiment 7 is increased by 168%.

[0104] Example 8

[0105] The same as Example 1, except that 0.8% of the heat storage agent stearic acid is added, and water accounts for 4.2% of the total weight of the polymer emulsion slurry. After testing, the tensile bonding strength of the concrete interface of this embodiment is 6.18MPa; compared with Comparative Example 1, the tensile bonding strength of the concrete interface of this embodiment is increased by 193%.

[0106] Example 9

[0107] The same as Example 2, except that 1.0% of the heat storage agent n-octadecane is added, and water accounts for 7.5% of the total weight of the polymer emulsion slurry. After testing, the tensile bonding strength of the concrete interface of this example is 6.25MPa; compared with Comparative Example 2, the tensile bonding strength of the concrete interface of this example is increased by 196%.

[0108] Example 10

[0109] Same as Example 3, except that 2.0% of a mixture of n-eicosane and pearl fatty acid is added, the mass ratio of the two is 3:7, and water accounts for 9.5% of the total weight of the polymer emulsion slurry; after printing, the microwave generator and the magnetic field generator are turned on at the same time, the printed component is placed in the magnetic field and the microwave generator, and the 3D printed concrete component sprayed with the polymer emulsion slurry is magnetized and microwave treated, the magnetic field intensity is 650KA / m, the magnetization time is 12min, the frequency of changing the direction of the magnetic field is 75Hz, the microwave frequency of the polymer emulsion slurry is 1000KHz, and the radiation time is 15min. After testing, the tensile bonding strength of the concrete interface of this embodiment is 10.9MPa; compared with Comparative Example 3, the tensile bonding strength of the concrete interface of this embodiment is increased by 296%.

[0110] Embodiment 11

[0111] 1) weighing raw materials according to the formula of polymer emulsion; in terms of mass percentage, the polymer emulsion includes: the response material includes hydroxyl iron powder, carbonyl iron powder and nano iron powder with a particle size of less than 10 μm, the mass ratio of the three is 2:3:5, and the response material accounts for 20% of the total weight of the polymer emulsion; the aqueous emulsion includes polystyrene emulsion and styrene butadiene emulsion, the mass ratio of the two is 6:4, and the aqueous emulsion accounts for 70% of the total weight of the polymer emulsion; the stabilizer includes nano SiO2 particles (particle size <0.5 μm) and graphene nanosheets (sheet diameter <10 μm, thickness <10 nm), the mass ratio of the two is 6:4, and the stabilizer accounts for 5% of the total weight of the polymer emulsion; the solubilizer is nano CSH, accounting for 2% of the total mass of the total polymer emulsion, and water accounts for 3% of the total weight of the polymer emulsion;

[0112] 2) Mixing the aqueous emulsion and water, adding the response material and the additive to the mixture at a stirring speed of >10000 rpm, and stirring evenly to obtain a polymer emulsion for concrete 3D printing; spraying the steel bars (the steel bars have a diameter of 15 mm and a length of 6 cm) to be embedded in the concrete, so that the coverage rate of the polymer emulsion on the steel bar surface is 50%;

[0113] 3) Print a layer of concrete, and evenly spray a layer of polymer emulsion on its surface (the spraying amount is 1.0% of the mass of the cementitious material of this layer of concrete); print another layer of concrete (material and thickness are the same as before), and spray another layer of polymer emulsion (spraying amount is the same as before); repeat this operation until the concrete 3D printed blank is printed; the last layer is a concrete layer; it contains four layers of concrete and three layers of polymer emulsion;

[0114] 4) Inserting the steel bars sprayed with the polymer emulsion layer into the 3D printed concrete blank in a direction perpendicular to the concrete printing surface, inserting a total of 6 steel bars, and arranging the steel bars in a 2×3 matrix;

[0115] 5) After the reinforcement is planted, turn on the magnetic field generator, place the concrete 3D printed blank in the magnetic field, and magnetize the 3D printed concrete component with reinforcement sprayed with polymer emulsion. The magnetic field intensity is 450KA / m, the magnetization time is 10 min, and the frequency of changing the magnetic field direction is 100 Hz to obtain a 3D printed concrete component.

[0116] According to the test, the bond strength of the concrete reinforcement in this embodiment is 15.8 MPa.

[0117] Comparative Example 8

[0118] Same as Example 11, except that the polymer emulsion was not sprayed onto the steel bars and no energy excitation was performed.

[0119] After testing, the bond strength of the reinforced concrete in this comparative example is 12 MPa; compared with comparative example 8, the bond strength of the concrete and steel bars in Example 11 is increased by 32%.

[0120] It can be seen from the test data of the above embodiments and comparative examples that by arranging the polymer emulsion slurry of the present invention between the concrete layers printed layer by layer, the interfacial tensile bonding strength of the concrete 3D printed products obtained by 3D printing is ≥5MPa, and compared with the interface agent in the prior art, the bonding strength is increased by more than 1.6 times, and the steel bar gripping force is increased by more than 0.3 times; in particular, when a suitable response material is added and after a solubilizing agent is introduced into the polymer emulsion slurry, its strength can be further increased to more than 10MPa through magnetization treatment and microwave treatment, and its bonding strength is increased by more than 2.9 times.

[0121] The technical features in the claims and / or the specification of the present invention may be combined, and the combination is not limited to the combination obtained by reference in the claims. The technical solution obtained by combining the technical features in the claims and / or the specification is also within the protection scope of the present invention.

[0122] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A polymer emulsion slurry for concrete 3D printing, characterized in that: Calculated by mass percentage, it includes: 48% to 75% aqueous emulsion, 10% to 30% response material, 5% to 15% stabilizer, 1% to 5% solubilizer and 5% to 27% water; wherein the response material is selected from at least one of iron powder, aluminum powder and tin powder; and the particle size of the response material is less than 10 μm.

2. The polymer emulsion slurry according to claim 1, characterized in that The iron powder is selected from at least one of hydroxy iron powder, carbon-based iron powder, carbonyl iron powder, nano iron powder and nano Fe3O4.

3. The polymer emulsion slurry according to claim 1, characterized in that: The response material includes a first response material and a second response material; the first response material can vibrate under the action of a high-frequency magnetic field; and the second response material can absorb energy under microwave excitation.

4. The polymer emulsion slurry according to claim 3, characterized in that: The first response material is selected from at least one of hydroxyl iron powder, carbon-based iron powder, carbonyl iron powder, nano iron powder and nano Fe3O4; the second response material is selected from aluminum powder and / or tin powder; the mass ratio of the first response material to the second response material is 1:0.5~10.

5. The polymer emulsion slurry according to claim 1, characterized in that: The aqueous emulsion is selected from at least one of polystyrene emulsion, polyaniline emulsion, styrene-butadiene emulsion and polyacrylic acid emulsion.

6. The polymer emulsion slurry according to claim 1, characterized in that: The stabilizer is selected from at least one of nano-SiO2 particles, graphene nanosheets and carbon nanotubes.

7. The polymer emulsion slurry according to claim 1, characterized in that: The solubilizing agent is CSH gel with a particle size of less than 0.5 μm.

8. The polymer emulsion slurry according to claim 1, characterized in that: It also includes 0.5% to 2% of a heat storage agent; the heat storage agent is selected from at least one of aliphatic hydrocarbon and fatty acid particles.

9. A method for preparing a polymer emulsion slurry for concrete 3D printing, characterized in that: It includes the following steps: 1) Weigh the raw materials according to the formula; The polymer emulsion slurry comprises, in terms of mass percentage, 48% to 75% of aqueous emulsion, 10% to 30% of response material, 5% to 15% of stabilizer, 1% to 5% of solubilizer and 5% to 27% of water; 2) Mixing the aqueous emulsion and water, adding the response material, stabilizer and solubilizer to the mixture at a stirring speed of >10000 rpm, and stirring evenly to obtain a polymer emulsion slurry for concrete 3D printing; wherein the response material is selected from at least one of iron powder, aluminum powder and tin powder; and the particle size of the response material is <10 μm.

10. Use of the polymer emulsion slurry for concrete 3D printing according to any one of claims 1 to 8 in concrete 3D printing.