Bionic cement emulsified asphalt composite material and preparation method and application thereof

Abstract

This invention discloses a biomimetic cement emulsified asphalt composite material, its preparation method, and its application, belonging to the technical field of cement and asphalt materials. The preparation method includes: granulating cement, Fe3O4 powder, SiC powder, a water-reducing agent, and water to obtain a spherical cement mixture; coating the surface of the spherical cement mixture with emulsified asphalt to obtain a preform, followed by static pressing; the mass ratio of cement to Fe3O4 powder is 100:1 to 100:2; the mass ratio of cement to SiC powder is 100:1 to 100:2; the mass ratio of cement to water-reducing agent is 100:0.15 to 100:0.3; the mass ratio of cement to water is 100:15 to 100:25; and the mass ratio of emulsified asphalt to cement is 8:100 to 20:100. This method is simple to operate and can prepare a biomimetic cement emulsified asphalt composite material with both high strength and high toughness, which can be used for repairing potholes and damage to asphalt pavements.

Description

Technical Field

[0001] This invention relates to the field of cement asphalt materials technology, and more specifically, to a biomimetic cement emulsified asphalt composite material, its preparation method, and its application. Background Technology

[0002] With the increasing demand for asphalt pavement maintenance, early-stage defects such as potholes and breaks are becoming more frequent, necessitating the development of high-performance repair materials that combine rapid repair capabilities with excellent road performance. Currently, cold patch repair materials are the mainstream approach for small-area localized maintenance. Among them, emulsified asphalt-based cold patch materials have become an important system for green and low-carbon maintenance due to their advantages such as strong construction adaptability, low energy consumption, and environmental friendliness. However, these materials still suffer from problems such as low early strength and insufficient road performance, and it is difficult to achieve a balance between strength and toughness.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a biomimetic cement emulsified asphalt composite material, its preparation method and application, in order to solve or improve the above-mentioned technical problems.

[0005] This invention can be implemented as follows: In a first aspect, the present invention provides a method for preparing a biomimetic cement emulsified asphalt composite material, comprising the following steps: granulating cement, Fe3O4 powder, SiC powder, water-reducing agent and water to obtain a spherical cement mixture; coating the surface of the spherical cement mixture with emulsified asphalt to obtain a preform; and statically pressing the preform. The mass ratio of cement to Fe3O4 powder is 100:1 to 100:2; the mass ratio of cement to SiC powder is 100:1 to 100:2. The mass ratio of cement to water-reducing agent is 100:0.15 to 100:0.3; The mass ratio of cement to water is 100:15 to 100:25; The mass ratio of emulsified asphalt to cement is 8:100 to 20:100.

[0006] In an optional embodiment, the average particle size of the Fe3O4 powder and the SiC powder is independently 200 nm to 500 nm.

[0007] And / or, the water-reducing agent is a polycarboxylate water-reducing agent; And / or, the emulsified asphalt is a cationic slow-cracking emulsified asphalt; And / or, the cement includes at least one of silicate cement, sulfoaluminate cement and phosphate cement.

[0008] In an optional implementation, water is added during granulation in the form of a water mist.

[0009] In an optional implementation, the water spraying time does not exceed 10 minutes.

[0010] In an optional implementation, the water spraying time is 5 to 10 minutes.

[0011] In an optional embodiment, the granulation speed is 35 r / min to 50 r / min.

[0012] In an optional embodiment, the mixing speed of the emulsified asphalt and spherical cement mixture is 10 r / min to 25 r / min.

[0013] In an optional embodiment, the mixing time of the emulsified asphalt and spherical cement mixture is 6 min to 10 min.

[0014] In an optional embodiment, emulsified bitumen is sprayed onto the surface of the spherical cement mixture.

[0015] In an alternative embodiment, the precast is a core-shell structure, wherein the core is formed of a spherical cement mixture and the shell is formed of emulsified bitumen.

[0016] In an optional embodiment, static pressure molding is performed at 20°C to 100°C and 3MPa to 7MPa.

[0017] In an optional embodiment, static pressure molding is carried out at 60°C to 100°C and 3MPa to 7MPa.

[0018] Secondly, the present invention provides a biomimetic cement emulsified asphalt composite material, which is prepared by any of the preparation methods described in the foregoing embodiments.

[0019] In an optional embodiment, the biomimetic cement emulsified asphalt composite material has at least one of the following characteristics: Feature 1: The flexural strength of the biomimetic cement emulsified asphalt composite material is not less than 8.6 MPa after curing for 7 days under standard conditions; Feature 2: After curing for 7 days under standard conditions, the flexural toughness of the biomimetic cement emulsified asphalt composite material is not less than 16.8 kJ / m. 3 ; Feature 3: The flexural strength of the biomimetic cement emulsified asphalt composite material is not less than 10.2 MPa after curing under standard conditions for 28 days; Feature 4: After curing under standard conditions for 28 days, the flexural toughness of the biomimetic cement emulsified asphalt composite material is not less than 30.4 kJ / m. 3 .

[0020] Thirdly, the present invention provides an application of the biomimetic cement emulsified asphalt composite material as described in any of the foregoing embodiments, for example, using the biomimetic cement emulsified asphalt composite material for repairing potholes and damage to asphalt pavements.

[0021] The beneficial effects of this invention include: This invention creatively employs a unique preparation process of granulation followed by coating and then static pressing to prepare a cement emulsified asphalt composite material with a biomimetic structure. In this process, firstly, cement, Fe3O4 powder, and SiC powder are granulated into a uniformly sized spherical cement mixture, forming brick-like units similar to those in mother-of-pearl. Then, emulsified asphalt is uniformly coated onto the surface of the spherical cement mixture through coating, forming a continuous soft interface layer. Finally, static pressing ensures close contact between the particles, forming a stable alternating "brick-and-mortar" structure. This biomimetic cement emulsified asphalt composite material possesses a brick-and-mortar ordered structure similar to mother-of-pearl, exhibiting high load-bearing capacity while achieving excellent toughness through crack deflection and energy dissipation, overcoming the challenge of simultaneously achieving strength and toughness in existing cement emulsified asphalt composite materials. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 The cross-section and internal structure diagram of the three-point bending fracture surface of the biomimetic cement emulsified asphalt composite material prepared in Example 1 are shown. Figure 2 The graph shows a comparison of the bending strength and bending toughness of the samples prepared in Example 1, Comparative Example 1 and Comparative Example 2 after a standard curing period of 7 days, obtained by a three-point bending test. Figure 3 The graph shows a comparison of the bending strength and bending toughness of the samples prepared in Example 1, Comparative Example 1, and Comparative Example 2 after a standard curing period of 28 days, obtained by a three-point bending test. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0025] The following is a detailed description of the biomimetic cement emulsified asphalt composite material, its preparation method, and its application provided by the present invention.

[0026] This invention provides a method for preparing a biomimetic cement emulsified asphalt composite material, comprising the following steps: S1: Cement, Fe3O4 powder, SiC powder, water-reducing agent and water are granulated to obtain a spherical cement mixture.

[0027] In some alternative embodiments, the mass ratio of cement to Fe3O4 powder can be from 100:1 to 100:2, such as 100:1, 100:1.2, 100:1.5, 100:1.8 or 100:2, or other values ​​within the range of 100:1 to 100:2.

[0028] Fe3O4 powder can facilitate faster and more uniform heat transfer to the cement matrix during static pressing. Insufficient Fe3O4 powder will impair heat transfer efficiency during static pressing; excessive Fe3O4 powder will negatively impact the mechanical properties of the final specimen.

[0029] The average particle size of Fe3O4 powder can be 200nm~500nm, such as 200nm, 250nm, 300nm, 350nm, 400nm, 450nm or 500nm, or other values ​​in the range of 200nm~500nm.

[0030] If the average particle size of Fe3O4 powder is less than 200 nm, it is not only prone to agglomeration, affecting the material properties, but also increases the production cost; if the average particle size of Fe3O4 powder is greater than 500 nm, it is not conducive to the heat transfer efficiency during static pressing.

[0031] In some alternative embodiments, the mass ratio of cement to SiC powder can be from 100:1 to 100:2, such as 100:1, 100:1.2, 100:1.5, 100:1.8 or 100:2, or other values ​​within the range of 100:1 to 100:2.

[0032] SiC powder can facilitate faster and more uniform heat transfer into the cement matrix during static pressing. Insufficient SiC powder will impair heat transfer efficiency during static pressing; excessive SiC powder will negatively impact cost control and the final mechanical properties of the specimen.

[0033] The average particle size of SiC powder can be 200nm~500nm, such as 200nm, 250nm, 300nm, 350nm, 400nm, 450nm or 500nm, or other values ​​in the range of 200nm~500nm.

[0034] If the average particle size of SiC powder is less than 200nm, the production cost will increase; if the average particle size of SiC powder is greater than 500nm, it will be detrimental to the heat transfer efficiency during static pressing.

[0035] In some alternative embodiments, the mass ratio of cement to water-reducing agent can be from 100:0.15 to 100:0.3, such as 100:0.15, 100:0.2, 100:0.25 or 100:0.3, or other values ​​within the range of 100:0.15 to 100:0.3.

[0036] Water-reducing agents can reduce the amount of water used in the granulation process. If the amount of water-reducing agent is too small, it is not conducive to obtaining uniform and dense spherical cement mixtures; if the amount of water-reducing agent is too large, it is not conducive to the formation of spherical cement mixtures.

[0037] Water-reducing agents can be, for example, polycarboxylate water-reducing agents.

[0038] In some alternative embodiments, the cement may include at least one of silicate cement, sulfoaluminate cement, and phosphate cement.

[0039] In some alternative implementations, the mass ratio of cement to water can be 100:15 to 100:25, such as 100:15, 100:20, 100:22 or 100:25, or other values ​​within the range of 100:15 to 100:25.

[0040] Water primarily reacts with cement through a hydration reaction. Insufficient water hinders the agglomeration and nucleation of the cement mixture; excessive water restricts the particle size of the cement mixture after nucleation to the range of 1mm to 3mm.

[0041] It should be noted that in this invention, water is added during granulation in the form of a water mist. That is, the water is not mixed with cement, Fe3O4 powder, SiC powder, and water-reducing agent in the conventional way, but is sprayed into the granulator in the form of a water mist, which induces the cement powder to agglomerate into nuclei under the action of rolling and collision. The cement spheres obtained after granulation serve as the rigid core unit of the biomimetic structure.

[0042] In some alternative embodiments, the water spraying time does not exceed 10 minutes. In some preferred embodiments, the water spraying time is 5 to 10 minutes, such as 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, or 10 minutes.

[0043] In some alternative embodiments, the rotation speed during granulation can be 35 r / min to 50 r / min, such as 35 r / min, 40 r / min, 45 r / min or 50 r / min, or other values ​​within the range of 35 r / min to 50 r / min.

[0044] If the granulation speed is too slow during the above granulation process, it will be difficult to obtain spherical cement mixture; if the granulation process is too fast, it will easily lead to the breakage of the formed spherical cement mixture.

[0045] S2: Emulsified asphalt is coated onto the surface of a spherical cement mixture to obtain a precast object.

[0046] In some alternative embodiments, emulsified asphalt is uniformly sprayed onto the surface of the spherical cement mixture, resulting in a continuous, uniform, and substantially consistent asphalt film on each cement mixture surface, thereby obtaining a stable precast structure with a "cement core-asphalt shell" structure. In this precast structure, the core is formed by spherical cement mixture, and the outer shell is formed by emulsified asphalt. The outer shell is uniformly adhered to the surface of the core.

[0047] In some alternative implementations, the mass ratio of emulsified asphalt to cement can be from 8:100 to 20:100, such as 8:100, 10:100, 15:100 or 20:100, or other values ​​within the range of 8:100 to 20:100.

[0048] Emulsified asphalt primarily serves to construct a flexible network to enhance the material's toughness. Insufficient emulsified asphalt usage is detrimental to improving material toughness; conversely, excessive usage is detrimental to enhancing material strength.

[0049] In some alternative implementations, the emulsified bitumen is a cationic slow-cracking emulsified bitumen.

[0050] In some optional embodiments, when mixing the emulsified asphalt with the spherical cement mixture, the rotation speed can be 10 r / min to 25 r / min, such as 10 r / min, 15 r / min, 20 r / min or 25 r / min, or other values ​​within the range of 10 r / min to 25 r / min. This can prevent the cement spheres from violently impacting and breaking during the coating process, thereby obtaining a core-shell structure precast with stable structure and uniform coating.

[0051] In some optional embodiments, the mixing time of the emulsified asphalt and spherical cement mixture is 6 min to 10 min, such as 6 min, 8 min or 10 min, or other values ​​within the range of 6 min to 10 min.

[0052] In some alternative implementations, emulsified bitumen is sprayed onto the surface of the spherical cement mixture.

[0053] In some alternative embodiments, the average particle size of the spherical cement mixture is 1 mm to 3 mm. If the average particle size of the spherical cement mixture is greater than 3 mm, it is easy to cause a decrease in the flexural toughness of the final biomimetic cement emulsified asphalt composite material.

[0054] S3: The preform is statically pressed into shape.

[0055] In some alternative embodiments, static pressing is performed at 20°C to 100°C and 3MPa to 7MPa.

[0056] The static pressure forming temperature can be 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, or 100℃, or other values ​​within the range of 20℃ to 100℃. The static pressure forming pressure can be 3MPa, 4MPa, 5MPa, 6MPa, or 7MPa, or other values ​​within the range of 3MPa to 7MPa.

[0057] In some preferred embodiments, static pressing is performed at 60°C to 100°C and 3MPa to 7MPa. Under these preferred conditions, the fluidity of the asphalt is improved, which accelerates the hydration reaction of the cement, allowing the biomimetic cement emulsified asphalt composite material to achieve high strength at an early stage.

[0058] In some more specific embodiments, the preform can be filled into a stainless steel mold, and then both can be placed together in a static press for static pressing. For example, the heating function of the static press is turned on first, and the temperature is set to 20°C to 100°C; after the static press has heated up to the working temperature, the mold and the material are placed together on the static press, and a pressure of 3MPa to 7MPa is applied and maintained for 25 to 35 minutes.

[0059] Building upon the above, this invention creatively employs a unique preparation process of granulation followed by coating and then static pressing to prepare a cement emulsified asphalt composite material with a biomimetic structure. In this process, firstly, cement, Fe3O4 powder, and SiC powder are granulated into a uniformly sized spherical cement mixture, forming brick-like units similar to mother-of-pearl. Subsequently, emulsified asphalt is uniformly coated onto the surface of the spherical cement mixture through coating, forming a continuous soft interface layer. Finally, static pressing ensures close contact between the particles, forming a stable alternating "brick-and-mortar" structure, thus effectively solving the bottleneck problem of achieving both strength and toughness in existing cement asphalt materials.

[0060] Accordingly, the present invention also provides a biomimetic cement emulsified asphalt composite material, which is prepared by the above preparation method.

[0061] In some alternative implementations, the biomimetic cement emulsified asphalt composite material, after curing for 7 days under standard conditions, has a flexural strength of not less than 8.6 MPa, for example, 8.69 MPa to 9.41 MPa.

[0062] In some alternative implementations, the biomimetic cement emulsified asphalt composite material exhibits a flexural toughness of not less than 16.8 kJ / m after curing under standard conditions for 7 days. 3 For example, it can be 16.84 kJ / m 3 ~23.06kJ / m 3 .

[0063] In some alternative implementations, the biomimetic cement emulsified asphalt composite material, after curing under standard conditions for 28 days, has a flexural strength of not less than 10.2 MPa, for example, 10.21 MPa to 11.28 MPa.

[0064] In some alternative implementations, the biomimetic cement emulsified asphalt composite material exhibits a flexural toughness of not less than 30.4 kJ / m after curing under standard conditions for 28 days. 3 For example, it can be 30.43 kJ / m 3 ~37.13kJ / m 3 .

[0065] This biomimetic cement emulsified asphalt composite material possesses an ordered brick-and-mortar structure similar to mother-of-pearl. While exhibiting high load-bearing capacity, it achieves excellent toughness through crack deflection and energy dissipation. Compared to pure cement matrices and conventional cement emulsified asphalt composite materials where all raw materials are directly mixed, it demonstrates higher toughness and crack resistance. Therefore, the biomimetic cement emulsified asphalt composite material provided by this invention is of great significance in overcoming the challenge of balancing strength and toughness in existing cement emulsified asphalt composite materials. It offers a new approach for developing high-performance emulsified asphalt-based cold patching materials, thereby promoting the further development of green and low-carbon maintenance.

[0066] In addition, the present invention also provides an application of the above-mentioned biomimetic cement emulsified asphalt composite material, for example, using the biomimetic cement emulsified asphalt composite material for the repair of potholes and damage to asphalt pavements.

[0067] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0068] The raw material information used in the following examples is as follows: The silicate cement was purchased from Zhucheng Yangchun Cement Co., Ltd., and the product model (batch) was P.O42.5. The polycarboxylate superplasticizer was purchased from Jiangsu Subote New Material Co., Ltd., product model (batch) PCA. ® -9 series polycarboxylate superplasticizer; Fe3O4 powder was purchased from Nangong Jingrui Alloy Products Co., Ltd., with an average particle size of 200nm~500nm; The SiC powder was purchased from Nangong Jingrui Alloy Products Co., Ltd., with an average particle size of 200nm~500nm. The basic components of the emulsified asphalt used in this experiment included base asphalt, cationic emulsifier, pH adjuster, and water. The base asphalt used was 70# base asphalt, commonly used in road engineering. The cationic emulsifier was EA-502 cold recycling emulsifier produced by Jiangsu Subote Co., Ltd. Since the cationic emulsion system requires strongly acidic conditions to remain stable, concentrated hydrochloric acid solution was used as the pH adjuster. Furthermore, to reduce interference from other impurity ions on the emulsification process, distilled water with a pH of 7.0 was used in the experiment. The specific preparation process of the emulsified asphalt includes the following four steps: (1) Raw material preparation First, heat the 70# base asphalt in a 170℃ oven until it melts and produces white smoke. Then, keep it at this temperature to ensure good fluidity when poured into a colloid mill. Simultaneously, measure a certain volume of distilled water and heat it to 65℃. Adjust the pH to an acidic range of 2-3 using concentrated hydrochloric acid. Next, accurately weigh the cationic emulsifier according to the designed ratio and add it to the warm water at a mass ratio of 1:39. Maintain the mixture under a 65℃ water bath with continuous stirring for 4 hours to ensure the emulsifier molecules are fully dissolved and activated, resulting in a homogeneous soap solution. That is, the soap solution consists of 1 part cationic emulsifier, 39 parts water, and a small amount of concentrated hydrochloric acid, the amount of which is used to adjust the pH of the soap solution to 2-3.

[0069] (2) Equipment preheating To prevent high-temperature asphalt from solidifying upon contact with cold air when it enters the colloid mill due to excessive temperature difference, the equipment must be preheated before emulsification. Specifically, boiling water is injected into the colloid mill system and circulated at 5000 r / min for about 1 minute. After the working environment temperature of the colloid mill rises, the accumulated water is drained, and the equipment is placed in a standby warm state.

[0070] (3) Emulsification shearing process Start the colloid mill, then pour the prepared 40 parts soap solution into the mill and circulate it at 5000 rpm for 30 seconds. During the high-speed shearing operation of the colloid mill, slowly and continuously pour 60 parts molten base asphalt into the feed inlet. During this process, use a round iron rod to stir the mixture at the feed inlet of the colloid mill to prevent asphalt from accumulating and clogging the feed inlet. After all the asphalt has been poured in, continue circulating and shearing the colloid mill for about 1 minute.

[0071] (4) Sample collection and post-processing After the shearing process is completed, immediately open the discharge valve and quickly transfer the prepared emulsified asphalt into a clean, sealed container. Then seal the container and place it in a room temperature water bath to cool, preventing emulsion deterioration due to residual heat. Once the sample has cooled to room temperature, label it and store it for later use.

[0072] Example 1 This embodiment provides a biomimetic cement emulsified asphalt composite material, the preparation method of which includes: S1: Place 100g of silicate cement, 0.3g of polycarboxylate superplasticizer, 2g of Fe3O4 powder, and 2g of SiC powder into a granulator. Set the granulator speed to 45r / min, turn on the equipment, and continuously and evenly spray water mist into the granulator to induce the cement powder, Fe3O4 powder, and SiC powder to agglomerate into nuclei through rolling and collision. The total amount of water sprayed is 25g, and the spraying time is 10min. The resulting granulation produces a spherical cement mixture.

[0073] S2: Screen the complete spherical cement mixture and put it back into the granulator, reducing the rotation speed to 15 r / min; at the same time, spray emulsified asphalt onto the surface of the cement mixture to form a stable precast with a core-shell structure; wherein, the total amount of emulsified asphalt is 8g, and the spraying time is 8min.

[0074] S3: Fill the above preform into a stainless steel mold, and then put both into a static pressure machine, apply a pressure of 5MPa and a high temperature static pressure treatment of 70℃ for 30 minutes.

[0075] Example 2 The difference between this embodiment and Embodiment 1 is that the mass ratio of emulsified asphalt to cement is 15:100.

[0076] Example 3 The difference between this embodiment and Embodiment 1 is that the mass ratio of emulsified asphalt to cement is 20:100.

[0077] Example 4 This embodiment provides a biomimetic cement emulsified asphalt composite material, the preparation method of which includes: S1: Place 100g of silicate cement, 0.15g of polycarboxylate superplasticizer, 1g of Fe3O4 powder, and 1g of SiC powder into a granulator. Set the granulator speed to 35r / min, turn on the equipment, and continuously and evenly spray water mist into the granulator to induce the cement powder, Fe3O4 powder, and SiC powder to agglomerate into nuclei through rolling and collision. The total amount of water sprayed is 15g, and the spraying time is 5min. The resulting granulation produces a spherical cement mixture.

[0078] S2: Screen the complete spherical cement mixture and put it back into the granulator, reducing the rotation speed to 10 r / min; at the same time, spray emulsified asphalt onto the surface of the cement mixture to form a stable precast with a core-shell structure; wherein, the total amount of emulsified asphalt is 8g, and the spraying time is 6min.

[0079] S3: Fill the above preform into a stainless steel mold, and then put both into a static pressure machine, apply a pressure of 3MPa and a high temperature static pressure treatment of 60℃ for 35 minutes.

[0080] Example 5 This embodiment provides a biomimetic cement emulsified asphalt composite material, the preparation method of which includes: S1: Place 100g of silicate cement, 0.3g of polycarboxylate superplasticizer, 1.5g of Fe3O4 powder, and 1.5g of SiC powder into a granulator. Set the granulator speed to 50r / min, turn on the equipment, and continuously and evenly spray water mist into the granulator to induce the cement powder, Fe3O4 powder, and SiC powder to agglomerate into nuclei through rolling and collision. The total amount of water sprayed is 20g, and the spraying time is 10min. The spherical cement mixture obtained after granulation is completed.

[0081] S2: Screen the complete spherical cement mixture and put it back into the granulator, reducing the rotation speed to 25 r / min; at the same time, spray emulsified asphalt onto the surface of the cement mixture to form a stable precast with a core-shell structure; wherein, the total amount of emulsified asphalt is 20g, and the spraying time is 10min.

[0082] S3: Fill the above preform into a stainless steel mold, and then put both into a static pressure machine, apply a pressure of 7MPa and a high temperature static pressure treatment of 100℃ for 25 minutes.

[0083] Example 6 The difference between this embodiment and embodiment 5 is that in S1, the water spraying time is 2 minutes.

[0084] Example 7 The difference between this embodiment and embodiment 5 is that in S1, the water spraying time is 15 minutes.

[0085] Comparative Example 1 This comparative example provides a cement emulsified asphalt composite material, the preparation method of which includes: S1: Put 100g of cement, 25g of water, 0.3g of polycarboxylate superplasticizer, 2g of Fe3O4 powder and 2g of SiC powder into a mixer and mix at high speed (200r / min) for 8min to obtain a moist and loose material. S2: Add 8g of emulsified asphalt to the material obtained in S1, and then continue to stir at high speed in the mixer (speed is the same as in step S1) to obtain a brown material; S3: Same as Example 1.

[0086] Comparative Example 2 The difference between this comparative example and Example 1 is that the raw material prepared is emulsified asphalt.

[0087] Comparative Example 3 The difference between this comparative example and Example 5 is that the mass ratio of emulsified asphalt to cement is 5:100.

[0088] Comparative Example 4 The difference between this comparative example and Example 5 is that the mass ratio of cement to Fe3O4 powder is 100:0.5.

[0089] Comparative Example 5 The difference between this comparative example and Example 5 is that the mass ratio of cement to SiC powder is 100:0.5.

[0090] Comparative Example 6 The difference between this comparative example and Example 5 is that the mass ratio of cement to SiC powder is 100:2.5.

[0091] Comparative Example 7 The difference between this comparative example and Example 5 is that the mass ratio of cement to water is 100:10.

[0092] Comparative Example 8 The difference between this comparative example and Example 5 is that the mass ratio of cement to water is 100:30.

[0093] Comparative Example 9 The difference between this comparative example and Example 5 is that the mass ratio of emulsified asphalt to cement is 2:100.

[0094] Comparative Example 10 The difference between this comparative example and Example 5 is that the mass ratio of emulsified asphalt to cement is 25:100.

[0095] Comparative Example 11 The difference between this comparative example and Example 5 is that the static pressure molding pressure is 1 MPa.

[0096] Comparative Example 12 The difference between this comparative example and Example 5 is that the static pressure molding pressure is 8 MPa.

[0097] Test case (1) Taking Example 1 as an example, the cross-section of the biomimetic cement emulsified asphalt composite material prepared in this example is as follows: Figure 1As shown in Figure (a), it can be seen from the figure that after static pressure treatment, cement ball particles exhibit multi-sized irregular interlocking characteristics at the cross-section.

[0098] (2) Taking Examples 1, 4 and 5 as examples, the core particle size and shell thickness of the preforms in the above examples were tested. The results showed that the average particle size of the core was within 1 mm to 3 mm.

[0099] (3) The products prepared in Examples 1-7 and Comparative Examples 1-12 were compared in terms of performance. The three-point bending strength at 7d and 28d was tested according to ASTM D790-17, and the bending toughness at 7d and 28d was tested according to ASTM D790-17. The test results are shown in Table 1 and Table 2. Figure 1 (b) Figure 2 and Figure 3 As shown.

[0100] The internal structure diagram of the three-point bending fracture surface of the biomimetic cement emulsified asphalt composite material prepared in Example 1 is shown below. Figure 1 As shown in Figure (b), it can be seen from the figure that the cross-section exhibits a layered feature, but is not a completely regular "brick and mortar" structure of equal thickness.

[0101] Figure 2 and Figure 3 In the example, "pure cement" corresponds to ratio 2, "direct mixing" corresponds to ratio 1, and the biomimetic structure corresponds to example 1.

[0102] Table 1 Test Results

[0103] As can be seen from Table 1, Embodiments 1-7 of the present invention, by constructing an ordered biomimetic structure, enable the asphalt phase to fully exert its interfacial toughening effect, while the cement particles maintain a high load-bearing capacity, thus achieving a balance between high strength and high toughness.

[0104] A comparison of Examples 1-3 shows that, compared to Example 1, the biomimetic cement emulsified asphalt composite material of Example 2 has an increased emulsified asphalt content, resulting in a thicker and more continuous soft layer inside the specimen, thus exhibiting increased flexural toughness. However, the increased soft layer thickness also reduces interlayer stiffness, leading to a decrease in flexural strength. Similarly, the biomimetic cement emulsified asphalt composite material of Example 3, compared to Example 2, further increases the emulsified asphalt content, resulting in a thicker and more continuous soft layer inside the specimen, thus exhibiting increased flexural toughness. However, the increased soft layer thickness also reduces interlayer stiffness, resulting in a decrease in flexural strength.

[0105] As can be seen from the comparison between Example 1 and Comparative Example 1, under the condition that the amount of each raw material is the same, Comparative Example 1 adopts the traditional direct mixing process, which results in the random distribution of cement and asphalt. That is, the interior of the specimen is a disordered arrangement of soft and hard phases, which makes it difficult to form an ordered "brick and mortar" structure. As a result, the material sacrifices strength while gaining flexibility. The bending toughness and bending strength of the obtained product are both less than those of Example 1.

[0106] As can be seen from the comparison between Example 1 and Comparative Example 2, Comparative Example 2 did not add emulsified asphalt, and the specimen lacked a soft phase that could hinder crack propagation. It was a brittle material overall, and the cracks in brittle materials are straight-through fractures. Therefore, its bending toughness was less than that of Example 1.

[0107] As can be seen from Examples 5 and Comparative Examples 4-10, when the proportion of raw materials used in preparation is not appropriate, it is difficult to obtain a biomimetic cement emulsified asphalt composite material with both high strength and toughness.

[0108] Compared with Example 5, the biomimetic cement emulsified asphalt composite material of Comparative Example 3 had a reduced amount of emulsified asphalt, which reduced the thickness and continuity of the soft layer inside the specimen. As a result, the failure process could not fully utilize the toughening mechanism of the "brick and mortar" structure, thus the bending toughness was reduced, but the bending strength was increased.

[0109] As can be seen from Example 5 and Comparative Examples 11-12, if the static pressure molding conditions are not set properly, it is difficult to obtain a biomimetic cement emulsified asphalt composite material with both high strength and toughness.

[0110] In summary, this invention creatively employs a unique preparation process of granulation followed by coating and then static pressing to prepare a cement emulsified asphalt composite material with a biomimetic structure. In this process, firstly, cement, Fe3O4 powder, and SiC powder are granulated into a uniformly sized spherical cement mixture, forming brick-like units similar to mother-of-pearl. Then, emulsified asphalt is uniformly coated onto the surface of the spherical cement mixture through coating, forming a continuous soft interface layer. Finally, static pressing ensures close contact between the particles, forming a stable "brick-and-mortar" alternating structure, thus effectively solving the bottleneck problem of achieving both strength and toughness in existing cement asphalt materials.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a biomimetic cement emulsified asphalt composite material, characterized in that, Includes the following steps: Cement, Fe3O4 powder, SiC powder, water-reducing agent, and water are granulated to obtain a spherical cement mixture; emulsified asphalt is coated onto the surface of the spherical cement mixture to obtain a preform; the preform is then statically pressed into shape. The mass ratio of the cement to the Fe3O4 powder is 100:1 to 100:2; the mass ratio of the cement to the SiC powder is 100:1 to 100:

2. The mass ratio of the cement to the water-reducing agent is 100:0.15 to 100:0.3; The mass ratio of cement to water is 100:15 to 100:25; The mass ratio of the emulsified asphalt to the cement is 8:100 to 20:

100.

2. The preparation method according to claim 1, characterized in that, The average particle size of the Fe3O4 powder and the SiC powder are independently 200nm~500nm; And / or, the water-reducing agent is a polycarboxylate water-reducing agent; And / or, the emulsified asphalt is a cationic slow-cracking emulsified asphalt; And / or, the cement includes at least one of silicate cement, sulfoaluminate cement and phosphate cement.

3. The preparation method according to claim 1, characterized in that, Water is added during granulation in the form of a water mist; Preferably, the water spraying time does not exceed 10 minutes; Ideally, the water spraying time should be 5 to 10 minutes.

4. The preparation method according to claim 1, characterized in that, During granulation, the rotation speed is 35 r / min to 50 r / min.

5. The preparation method according to claim 1, characterized in that, When the emulsified asphalt is mixed with the spherical cement mixture, the rotation speed is 10 r / min to 25 r / min; Preferably, the mixing time of the emulsified asphalt and the spherical cement mixture is 6 min to 10 min; More preferably, the emulsified bitumen is sprayed onto the surface of the spherical cement mixture.

6. The preparation method according to claim 1, characterized in that, The precast structure is a core-shell structure, wherein the core is formed of a spherical cement mixture and the outer shell is formed of emulsified asphalt.

7. The preparation method according to claim 1, characterized in that, Static pressing is carried out at 20℃~100℃ and 3MPa~7MPa. Preferably, static pressure molding is carried out at 60℃~100℃ and 3MPa~7MPa.

8. A biomimetic cement emulsified asphalt composite material, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 7.

9. The biomimetic cement emulsified asphalt composite material according to claim 8, characterized in that, The biomimetic cement emulsified asphalt composite material has at least one of the following characteristics: Feature 1: The biomimetic cement emulsified asphalt composite material has a flexural strength of not less than 8.6 MPa after curing for 7 days under standard conditions; Feature 2: After curing for 7 days under standard conditions, the biomimetic cement emulsified asphalt composite material exhibits a flexural toughness of not less than 16.8 kJ / m. 3 ; Feature 3: The biomimetic cement emulsified asphalt composite material has a flexural strength of not less than 10.2 MPa after curing under standard conditions for 28 days; Feature 4: After curing under standard conditions for 28 days, the biomimetic cement emulsified asphalt composite material exhibits a flexural toughness of not less than 30.4 kJ / m. 3 .

10. An application of the biomimetic cement emulsified asphalt composite material as described in claim 8 or 9, characterized in that, The biomimetic cement emulsified asphalt composite material is used for repairing potholes and damage to asphalt pavements.

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