Stomatal modifier, its preparation method and application

Abstract

The application provides a pore modifier and a preparation method and application thereof. The pore modifier comprises an organic coating agent emulsion and a solid carrier coated by the organic coating agent emulsion; the organic coating agent is one or more of a phenylpropyl resin, an epoxy resin, a glue powder and a dispersible latex powder. The pore modifier for a cement-based material provided by the application can effectively control the size and quantity of pores introduced into the cement-based material in various severe environments, especially in low-pressure and / or extremely cold environments, so as to not only ensure the frost resistance and non-cracking of concrete, but also guarantee the strength and durability of the concrete. In the preparation method, the organic coating agent, an emulsifier and water are mixed first, so that the organic coating agent is well emulsified; then the hydrophobic component is mixed, and finally the solid carrier is mixed, which is helpful to generate a good structure of the hydrophobic coated inorganic carrier, so as to guarantee the long-term stability of the emulsion and form stable small pores in the cement-based material.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and to a pore modifier, its preparation method and application; particularly to a pore modifier for cement-based materials, its preparation method and application. Background Technology

[0002] With the development of concrete engineering construction, the application range of cement-based materials has gradually diversified. In projects located in environments with large temperature differences and freeze-thaw damage, air-entraining agents are often added to mortar or concrete to improve the concrete's freeze-thaw resistance. An air-entraining agent is an admixture that introduces a large number of uniformly distributed microbubbles into the mortar or concrete during the mixing process and retains them after hardening. There are many types of air-entraining agents.

[0003] Air-entraining agents increase the fluidity of cementitious materials by entraining air to generate bubbles. Simultaneously, it's crucial to ensure sufficient bubble stability so that numerous micropores form within the hardened cementitious material, thereby improving its freeze-thaw resistance. To enhance bubble stability, foam stabilizers are often added to the air-entraining agent (e.g., CN 109758966A). However, in extremely cold, low-pressure, or even vacuum environments, bubble stability is difficult to guarantee, making it impossible to form micropores within the hardened cementitious material.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] This invention provides a pore modifier, its preparation method, and its application, to address the deficiency of unstable bubbles in existing technologies under extreme cold or vacuum environments. The pore modifier of this invention can generate stable micropores, improving the freeze-thaw resistance of cement-based materials.

[0006] This invention provides a pore modifier, which includes an organic coating agent and a solid carrier;

[0007] Organic coating agents include styrene-acrylic resin, epoxy resin, adhesive powder, and one or more organic components that can be dispersed in latex powder.

[0008] The organic coating agent is styrene-acrylic resin, epoxy resin, or adhesive powder, and may be one or more of the dispersed latex powder.

[0009] Preferably, the pore modifier comprises an organic coating agent and a solid carrier coated by the organic coating agent;

[0010] More preferably, the organic coating agent is styrene-acrylic resin and / or epoxy resin.

[0011] The porosity modifier of this invention can adapt to extremely cold regions. Even under extreme conditions such as large temperature differences between day and night, and when building materials are subjected to extreme conditions, it can still maintain stable and relatively uniform micropores, thereby improving the frost resistance of building materials.

[0012] This invention coats an organic coating agent emulsion onto the outer surface of a solid carrier, ensuring a strong bond between them even in extreme environments (extreme cold, repeated freeze-thaw cycles, or low pressure conditions), forming a stable coating. Adding this coating to the concrete during the mixing process creates pores between the coating and the cementitious material, thus ensuring the controllability of the pore structure in the concrete under various harsh and extreme environmental conditions (especially extreme cold, repeated freeze-thaw cycles, or low pressure).

[0013] To meet the above requirements, the solid carrier must provide good support, ensuring that the encapsulation space formed with the organic encapsulating agent does not collapse even under extreme environmental conditions and maintains a stable structure. Without a solid carrier, if the encapsulating agent is added alone to the cementitious material, it is easier for it to form an organic film layer that inserts into the cementitious material, but this is not a reasonable pore structure for cementitious materials. With the support of a solid carrier, the organic components can form controllable spherical pores.

[0014] Organic coating agents must not only possess a certain degree of viscosity and good bonding performance with the solid carrier, but also have sufficient strength to maintain a stable bond between the coating agent and the solid carrier throughout the concrete mixing process. If the organic coating agent lacks sufficient strength, some of it may separate from the solid carrier, failing to form an ideal and controllable pore structure. Only when the organic coating agent possesses sufficient strength can it remain firmly bonded to the solid carrier, resulting in a relatively uniform coating that disperses evenly during mixing, forming uniform and controllable spherical pores, and ensuring the stability of the coating structure under subsequent repeated freeze-thaw cycles. Without other coating agents, relying solely on the solid carrier and hydrophobic components, the thickness of the hydrophobic layer formed on the surface is difficult to control, easily leading to drastic changes in pore size in extreme environments, thereby reducing the strength and durability of the concrete.

[0015] In some embodiments, the solid carrier is one or more of silica fume, slag powder, fly ash, quartz powder, metakaolin powder, and stone powder;

[0016] Preferably, the particle size of the solid carrier particles is less than 100 micrometers;

[0017] More preferably, the amount of the solid carrier added is 0.1% to 1% of the mass of the organic coating agent.

[0018] The selection and amount of solid carrier are crucial.

[0019] To create uniform and stable voids in concrete, the solid carrier must not only provide good support, ensuring the stability of the encapsulation space formed with the organic coating agent and preventing pore collapse, thus maintaining stable pores, but also ensure good bonding with the organic coating agent, keeping the organic coating agent always encapsulated on the surface of the solid carrier. Silica fume, slag powder, fly ash, quartz powder, metakaolin powder, or stone powder, especially silica fume, slag powder, quartz powder, and metakaolin powder, can meet the above requirements for solid carriers.

[0020] Only by adding an appropriate amount of solid carrier can uniform, stable, and controllable spherical pores be formed. If too much solid carrier is added, the organic coating agent cannot completely coat the solid carrier, the pore shape is uncontrollable, and spherical pores cannot be formed. If too little solid carrier is added, the organic coating layer will be too thick, or even the particles will stick together and be unevenly distributed, which may result in fewer pores and uneven pore dispersion in the concrete.

[0021] The porosity of concrete is generally required to be controlled below 200 micrometers. In this invention, the particle size of the solid carrier is required to be less than 100 micrometers. With the thickness of the coating layer, it can be ensured that the porosity of the cement-based material after hardening is less than 200 micrometers.

[0022] Only with the support of a suitable solid carrier can the coating form controllable, stable, and uniform spherical pores in the concrete.

[0023] In some embodiments, the pore modifier further includes a hydrophobic modifier; more preferably, the amount of the hydrophobic modifier added is 0.5 to 5% of the mass of the organic coating agent emulsion.

[0024] The amount of hydrophobic agent used is very critical.

[0025] If the amount of hydrophobic agent is too small, it cannot guarantee the formation of the required porous layer between the coating and the cement matrix; if the amount is too large, the porous layer will be too large, resulting in an excessively large pore structure and affecting the strength of the cement-based material.

[0026] More preferably, the organic coating agent further includes an emulsifier and water; preferably, the mass ratio of the organic component:water:emulsifier is (6-8):90:(2-4).

[0027] In some embodiments, the emulsifier is one or more of the following: Self-Leveling Plus O-25, AEO-9, OP-7, OP-10, Tween-20, Tween-80, Span-20, and Span-80.

[0028] Preferably, the hydrophobic modifier is one or more of polymethylhydrosiloxane, polydimethylsiloxane, hexadecyltrimethoxysilane, ethoxytrimethylsilane, hexamethyldisiloxane, n-butylsilane, isobutylsilane, and isooctylsilane.

[0029] During the solidification process, the emulsifier ensures that the organic coating agent is mixed evenly and maintains good contact and bonding with the solid carrier, thus guaranteeing its strength. Organic components: Water: The emulsifier, when mixed with an appropriate amount of hydrophobic modifier in a specific ratio, ensures that the emulsifier can fully emulsify the coating agent and hydrophobic modifier, guaranteeing the stability of the porosity improver system.

[0030] Furthermore, the hydrophobic component can interact with the emulsifier, eliminating foaming caused by the addition of emulsifiers in the coating agent and reducing foaming due to emulsifiers in cement-based materials. It also helps form a more stable hydrophobic coated emulsion, making the bond between the hydrophobic coated emulsion and the solid carrier more robust. Simultaneously, the hydrophobic component further ensures the sphericity of the pores formed in the cement material. Experiments have shown that the pores formed by the pore modifier of this invention in cement-based materials have a particle size approximately 30-100% larger than those of the modifier actually incorporated into the cement-based material, and the pore sphericity is better. This is mainly due to the effect of the outer hydrophobic component. In addition, the hydrophobic component can also improve the dispersibility of the pore modifier, ensuring the formation of a large number of independent closed pores and preventing the formation of a large number of interconnected pores.

[0031] This invention also provides a method for preparing a pore modifier, the method comprising the following steps:

[0032] The organic components and water are mixed for the first time to form an organic coating agent emulsion;

[0033] The organic coating agent emulsion and the solid carrier are mixed a second time to form the pore improver.

[0034] In some embodiments, the preparation method includes the following steps:

[0035] The organic components, emulsifier, and water are mixed for the first time to form a coating emulsion;

[0036] The coating agent emulsion, hydrophobic modifier, and solid carrier are mixed a second time to form the pore improver;

[0037] Preferably, the temperature of the first mixing is 20-80℃ and the rotation speed is 120-300 r / min; more preferably, the time of the first mixing is 10-20 min.

[0038] The temperature, rotation speed, and time of the first mixing are all controlled to ensure uniform dispersion of the coating agent emulsion. Within this temperature range, the emulsifier can fully emulsify the coating agent and hydrophobic modifier, ensuring the stability of the pore improver system.

[0039] In some embodiments, the second mixing specifically involves: first mixing the coating agent emulsion with the hydrophobic modifier, and then adding the solid carrier for further mixing;

[0040] Preferably, the mixing speed of the coating agent emulsion and the hydrophobic modifier is 30-90 r / min and the mixing time is 8-20 min;

[0041] More preferably, the mixing speed after adding the solid carrier is 120-300 r / min, and the time is 10-20 min.

[0042] Preferably, the mixing speed of the coating agent emulsion and the hydrophobic modifier is 30–90 r / min, with stirring for 3–5 min, maintaining the speed for 2–5 min, and then continuing to stir for 5–10 min. Within this speed and time range, the emulsifier can ensure the emulsification of the organic coating agent and the hydrophobic modifier. Maintaining low-speed stirring helps to better eliminate foaming caused by the addition of the emulsifier, which is conducive to the formation of a more stable hydrophobic coated emulsion and ensures the stability of the pore modifier system.

[0043] The present invention also provides a concrete, wherein the raw materials of the concrete include cement and a pore modifier, wherein the pore modifier is the pore modifier described above or a pore modifier prepared by the preparation method described above.

[0044] In some embodiments, the raw materials for the concrete include cement, fly ash, mineral powder, sand, limestone aggregate, water, and water-reducing agent.

[0045] Preferably, the raw materials for each cubic meter of concrete include 2 to 10 kg of the porosity modifier.

[0046] Adding too much porosity modifier may cause adhesion between the coatings and uneven porosity in the concrete; adding too little porosity modifier may result in uneven porosity in the concrete or fewer pores in the concrete, leading to insufficient frost resistance.

[0047] The present invention also provides an application of the pore modifier described above or the pore modifier prepared by the preparation method described above or the concrete described above, wherein the pore modifier or the concrete is applied to building decoration materials.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] The solid carrier, organic coating layer, and hydrophobic component of this invention form an organic whole. This allows building materials containing the pore modifier to adapt to various harsh and extreme environments, especially extremely cold and low-pressure environments. Even under conditions of large diurnal temperature variations and repeated freeze-thaw cycles, they can maintain stable micropores. It can effectively control the size and number of pores introduced into cement-based materials, ensuring not only the freeze-thaw resistance and crack prevention of concrete, but also guaranteeing its strength and durability.

[0050] The raw materials used in the porosity modifier of this invention are relatively inexpensive and readily available. By coating the hydrophobic organic components onto a solid carrier, a stable hydrophobic coating can be formed, which can form uniform, controllable, and stable spherical pores in concrete.

[0051] The method for preparing a cement-based material pore modifier proposed in this invention involves first mixing an organic coating agent, an emulsifier, and water to ensure good emulsification of the organic coating agent; then mixing it with a hydrophobic component; and finally mixing it with a solid carrier. This helps to generate a good hydrophobic coating layer that covers the inorganic carrier, ensuring the long-term stability of the emulsion and forming stable micropores in the concrete. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0053] Figure 1 This is one of the electron microscope images of concrete provided in Embodiment 1 of the present invention;

[0054] Figure 2 This is the second electron microscope image of concrete provided in Embodiment 1 of the present invention;

[0055] Figure 3 This is the third electron microscope image of concrete provided in Embodiment 1 of the present invention;

[0056] Figure 4 This is an electron microscope image of concrete provided in Embodiment 2 of the present invention;

[0057] Figure 5 This is an electron microscope image of ordinary concrete. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0059] In some specific embodiments, the pore modifier includes an organic coating agent emulsion and a solid carrier coated by the organic coating agent emulsion;

[0060] Organic coating agents include styrene-acrylic resin, epoxy resin, adhesive powder, and one or more organic components that can be dispersed in latex powder.

[0061] Specifically, the solid carrier is one or more of silica fume, slag powder, fly ash, quartz powder, metakaolin powder, and stone powder;

[0062] Preferably, the particle size of the solid carrier particles is less than 100 micrometers;

[0063] More preferably, the amount of the solid carrier added is 0.1% to 1% of the mass of the organic coating agent emulsion.

[0064] More specifically, the pore improver further includes a hydrophobic modifier; preferably, the amount of the hydrophobic modifier added is 0.5 to 5% of the mass of the organic coating agent emulsion;

[0065] More preferably, the organic coating agent further includes an emulsifier and water; even more preferably, the mass ratio of the organic coating agent:water:emulsifier is (6-8):90:(2-4).

[0066] Specifically, the emulsifier is one or more of the following: Self-leveling compound O-25, AEO-9, OP-7, OP-10, Tween-20, Tween-80, Span-20, and Span-80.

[0067] Preferably, the hydrophobic modifier is one or more of polymethylhydrosiloxane, polydimethylsiloxane, hexadecyltrimethoxysilane, ethoxytrimethylsilane, hexamethyldisiloxane, n-butylsilane, isobutylsilane, and isooctylsilane.

[0068] The following is combined Figure 1 The porosity modifier of the present invention is described.

[0069] Example 1

[0070] This embodiment provides a pore modifier (SES), and the electron microscope image is shown below. Figure 1-3 ( Figure 1 This is an overall electron microscope image. Figure 2 and Figure 3 It is a single pore. Figure 2 The coating is in the pores. Figure 3 The coating falls off, leaving only pores. The preparation method of the pore modifier includes the following steps:

[0071] (1) Add epoxy resin, water and Tween-20 to the reactor in a ratio of 6:90:4, heat in a water bath at 60°C, and stir at a speed of 120-300 r / min for 18 min to make the coating agent emulsion evenly dispersed.

[0072] (2) Add 2% polydimethylsiloxane to the reactor and stir at a speed of 30-90 r / min for 5 min; then continue stirring for 8 min.

[0073] (3) Add 0.5% silica fume to the reactor and stir rapidly for 16 minutes to form a stable porosity modifier emulsion.

[0074] Example 2

[0075] This embodiment provides a pore modifier (BJK), and the electron microscope image is shown below. Figure 4 The preparation method of the pore improver includes the following steps:

[0076] (1) Add styrene-acrylic resin, water and AEO-9 to the reactor in a ratio of 8:90:2, heat in a water bath at 60°C, and stir at a speed of 120-300 r / min for 10 min to make the coating agent emulsion evenly dispersed.

[0077] (2) Add 1% polymethylhydrosiloxane to the reactor and stir at a speed of 30-90 r / min for 5 min, and continue stirring for 7 min.

[0078] (3) Add 0.5% mineral powder to the reactor and stir rapidly for 20 minutes to form a stable modifier emulsion.

[0079] Example 3

[0080] This embodiment provides a porosity modifier (JJP), the preparation method of which includes the following steps:

[0081] Add the adhesive powder, water, and Span-20 to the reactor in a ratio of 8:90:2, heat in a 60°C water bath, and stir at a speed of 120-300 r / min for 15 min to ensure uniform dispersion of the coating agent emulsion.

[0082] (2) Add 0.5% hexadecyltrimethoxysilane to the reactor and stir at a speed of 30-90 r / min for 4 min, then continue stirring for 8 min.

[0083] (3) Add 1% metakaolin to the reactor and stir rapidly for 15 minutes to form a stable porosity modifier emulsion.

[0084] Example 4

[0085] This embodiment provides a pore modifier (KYS), and the preparation method of the pore modifier includes the following steps:

[0086] (1) Add redispersible latex powder, water and AEO-9 to the reactor in a ratio of 8:90:2, heat in a water bath at 60°C and stir at a speed of 120-300 r / min for 15 min to make the coating agent emulsion evenly dispersed.

[0087] (2) Add 0.5% isooctylsilane to the reactor and stir at a speed of 30-90 r / min for 5 min, and continue stirring for 7 min.

[0088] (3) Add 0.5% quartz powder to the reactor and stir rapidly for 15 minutes to form a stable modifier emulsion.

[0089] Comparative Example 1

[0090] This embodiment provides a pore modifier (SE), the preparation method of which includes the following steps:

[0091] (1) Add epoxy resin, water and Tween-20 to the reactor in a ratio of 6:90:4, heat in a water bath at 60°C, and stir at a speed of 120-300 r / min for 15 min to make the coating agent emulsion evenly dispersed.

[0092] (2) Add 2% polydimethylsiloxane to the reactor and stir at a speed of 30-90 r / min for 5 min, then continue stirring for 7 min to form a stable modifier emulsion.

[0093] Comparative Example 2

[0094] This comparative example provides a pore modifier (S), the preparation method of which includes the following steps:

[0095] Epoxy resin, water, and Tween-20 were added to the reactor in a ratio of 6:90:4. The reactor was heated in a water bath at 60°C and stirred at a speed of 120-300 r / min for 15 min to ensure that the coating agent emulsion was evenly dispersed and formed a stable modifier emulsion.

[0096] Comparative Example 3

[0097] This embodiment provides a pore modifier (SJK), the preparation method of which includes the following steps:

[0098] (1) Add silicone acrylic resin, water and AEO-9 to the reactor in a ratio of 8:90:2, heat in a water bath at 60°C, and stir at a speed of 120-300 r / min for 15 min to make the coating agent emulsion evenly dispersed.

[0099] (2) Add 1% polymethylhydrosiloxane to the reactor and stir at a speed of 30-90 r / min for 5 min, then continue stirring for 7 min;

[0100] (3) Add 0.5% mineral powder to the reactor and stir rapidly for 15 minutes to form a stable modifier emulsion.

[0101] Comparative Example 4

[0102] This embodiment provides a pore modifier (XJK), the preparation method of which includes the following steps:

[0103] (1) Add acrylic acid, water and AEO-9 to the reactor in a ratio of 8:90:2, heat in a water bath at 60°C, and stir at a speed of 120-300 r / min for 10-20 min to make the coating agent emulsion evenly dispersed.

[0104] (2) Add 1% polymethylhydrosiloxane to the reactor and stir at a speed of 30-90 r / min for 5 min, then continue stirring for 7 min;

[0105] (3) Add 0.5% mineral powder to the reactor and stir rapidly for 10-20 minutes to form a stable modifier emulsion.

[0106] Comparative Example 5

[0107] This embodiment provides a pore modifier (ES), the preparation method of which includes the following steps:

[0108] (1) Water: Tween-20 is added to the reactor at a ratio of 96:4. The reactor is heated in a water bath at 60°C and stirred at a speed of 120-300 r / min for 18 min to make the coating agent emulsion evenly dispersed.

[0109] (2) Add 2% polydimethylsiloxane to the reactor and stir at a speed of 30-90 r / min for 5 min; keep for 3 min, and then continue stirring for 8 min.

[0110] (3) Add 0.5% silica fume to the reactor and stir rapidly for 16 minutes to form a stable porosity modifier emulsion.

[0111] Experimental Example 1

[0112] This embodiment provides a pore modifier (XJ), the preparation method of which includes the following steps:

[0113] (1) Add redispersible latex powder, water and AEO-9 to the reactor in a ratio of 8:90:2, heat in a water bath at 60°C and stir at a speed of 120-300 r / min for 15 min to make the coating agent emulsion evenly dispersed.

[0114] (2) Add 0.5% quartz powder to the reactor and stir rapidly for 15 minutes to form a stable modifier emulsion.

[0115] Experimental Example 2

[0116] This embodiment provides a pore modifier (SS), the preparation method of which includes the following steps:

[0117] (1) Add epoxy resin and water to the reactor at a ratio of 7:90, heat in a water bath at 62°C, and stir at a speed of 120-300 r / min for 15 min to make the emulsion disperse evenly and form a coating agent emulsion.

[0118] (2) Add 2% polydimethylsiloxane to the reactor and stir at a speed of 30-90 r / min for 4 min; then continue stirring for 6 min.

[0119] (3) Add 0.6% silica fume to the reactor and stir rapidly for 16 minutes to form a stable porosity modifier emulsion.

[0120] The porosity modifier obtained in the above experiments was used with cement and other materials to prepare frost-resistant concrete. The raw materials are as follows:

[0121] PI 42.5 cement, grade II fly ash, S95 mineral powder, river sand, fineness modulus 2.6, limestone aggregate (5-20mm), polycarboxylate superplasticizer, and porosity modifier.

[0122] The raw material formula for concrete is shown in Table 1.

[0123] Table 1. Concrete mix proportions (kg / m³) 3 )

[0124]

[0125] Concrete was prepared according to the mix proportions in Table 1, with a porosity modifier dosage of 3 kg / m³. 3 .

[0126] 1. Routine environmental performance testing

[0127] In this experiment, the performance of the above-mentioned concrete was tested according to the test methods of GB 50081-2019, GB 50082-2009, and DLT5150-2001. The results are shown in Table 2.

[0128] Table 2 Performance Indicators of Different Concretes

[0129]

[0130]

[0131] Table 2 shows that, compared with ordinary concrete (without the addition of a porosity modifier, such as...) Figure 5 Compared to the previous examples, the concrete prepared with the porosity modifier of this invention (Examples 1-4) showed improved 28-day strength and significantly reduced air bubble spacing coefficients by 77%, 75%, 74%, and 74%, respectively, resulting in a marked improvement in the concrete's freeze-thaw resistance. Comparative Example 1, using only a coating agent and a hydrophobic modifier to prepare porosity modifier SE, and Comparative Example 2, using only a coating agent to prepare porosity modifier S, reduced the air bubble spacing coefficient of the concrete by 46% and 30%, respectively, with limited improvement in freeze-thaw resistance. This is related to the fact that the coating agent cannot form spherical pores in the concrete. Although adding organic components alone to cementitious materials makes it easier to form an organic film layer inserted into the cementitious material, it cannot form a suitable pore structure within the cementitious material.

[0132] Furthermore, in Comparative Example 3 using silicone-acrylic resin and Comparative Example 4 using acrylic resin as coating agents, the reduction in the air bubble spacing coefficient of the concrete was not significant, decreasing by only 24% and 22% respectively. The improvement in frost resistance was also not significant. This is mainly due to the unstable coating structure and / or insufficient coating film strength of these two coating agents. Therefore, these two organic reagents are not suitable as coating agents.

[0133] In Comparative Example 5, the ES component lacked an organic coating layer. Its actual function was that of an emulsified hydrophobic component, acting similarly to a defoamer, and it could not form the designed pore structure. While it could reduce the air bubble spacing coefficient of the concrete, it would decrease the concrete's strength and durability.

[0134] No hydrophobic component was added to XJ in Experiment 1, and the designed pores did not form in the concrete. The emulsified hydrophobic component has an antifoaming effect, which can eliminate large air bubbles introduced by the water-reducing agent. The pores in XJ concrete are mainly formed by polycarboxylate water-reducing agent, so the bubble spacing coefficient, durability, and strength are similar to those of ordinary concrete, indicating that it did not play a role.

[0135] In Experiment 2, no emulsifier was added to the SS. The hydrophobic component reacted with the cement, generating a large number of air bubbles, which led to an increase in the air bubble spacing coefficient of the concrete and a decrease in durability and strength.

[0136] 2. Concrete Experiments under Special Environments

[0137] The aforementioned concrete was subjected to comparative tests in extremely cold and low-pressure environments. Both environments were simulated using environmental test chambers. The extremely cold environment was simulated using a temperature range of 20℃ to -20℃, with one freeze-thaw cycle lasting 8 hours: 3 hours at 20℃ followed by a 0.5-hour cooling period, and 4 hours at -20℃ followed by a 0.5-hour warming period. The low-pressure environment was compared between a 40 kPa pressure environment and normal pressure (101 kPa). Concrete was prepared in the simulated environment, demolded after one day, and then cured according to standard conditions. Various performance tests were conducted after 28 days. The experimental results are shown in Table 3.

[0138] Table 3 Performance indicators of concrete under different environments

[0139]

[0140] As shown in Table 3, compared with ordinary concrete (without the addition of the porosity modifier), the concrete prepared with the porosity modifier of this invention (Examples 2 and 3) exhibits higher 28-day compressive strength, significantly reduced bubble spacing coefficient, and significantly improved freeze-thaw durability in extremely cold or low-pressure environments. The 28-day compressive strength, bubble spacing coefficient, and freeze-thaw durability of the concrete prepared with the porosity modifier of this invention are not significantly different between ordinary and extremely cold or low-pressure environments.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pore modifier, characterized in that, The pore modifier includes an organic coating agent, a hydrophobic modifier, and a solid carrier; Organic coating agents include styrene-acrylic resin, epoxy resin, adhesive powder, and one or more organic components that can be dispersed in latex powder; The amount of the hydrophobic modifier added is 0.5-5% of the mass of the organic coating agent; The organic coating agent further includes an emulsifier and water, wherein the mass ratio of the organic component to water to the emulsifier is (6~8):90:(2~4). The amount of the solid carrier added is 0.1-1% of the mass of the organic coating agent.

2. The porosity modifier according to claim 1, characterized in that, The solid carrier is one or more of the following: silica fume, slag powder, fly ash, quartz powder, metakaolin powder, and stone powder.

3. The porosity improver according to claim 2, characterized in that, The particle size of the solid carrier particles is less than 100 micrometers.

4. The porosity modifier according to claim 1, characterized in that, The emulsifier is one or more of the following: Self-Leveling Glycol O-25, AEO-9, OP-7, OP-10, Tween-20, Tween-80, Span-20, and Span-80.

5. The porosity modifier according to any one of claims 1-4, characterized in that, The hydrophobic modifier is one or more of the following: polymethylhydrosiloxane, polydimethylsiloxane, hexadecyltrimethoxysilane, ethoxytrimethylsilane, hexamethyldisiloxane, n-butylsilane, isobutylsilane, and isooctylsilane.

6. A method for preparing the porosity modifier according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: The organic components, emulsifier, and water are mixed for the first time to form a coating emulsion; The coating agent emulsion, hydrophobic modifier, and solid carrier are mixed a second time to form the pore improver.

7. The method for preparing the pore improver according to claim 6, characterized in that, The temperature of the first mixing is 20-80℃, and the rotation speed is 120-300 r / min.

8. The method for preparing the pore improver according to claim 7, characterized in that, The first mixing time is 10-20 minutes.

9. The method for preparing the pore improver according to claim 8, characterized in that, The second mixing process specifically involves first mixing the coating agent emulsion with the hydrophobic modifier, and then adding the solid carrier for further mixing.

10. The method for preparing the pore improver according to claim 9, characterized in that, The coating agent emulsion and the hydrophobic modifier are mixed at a speed of 30~90 r / min and stirred for 8~20 min.

11. The method for preparing the pore improver according to claim 9, characterized in that, After adding the solid carrier, the mixing speed is 120~300 r / min and the time is 10~20 min.

12. A type of concrete, characterized in that, The raw materials of the concrete include cement and a pore modifier, wherein the pore modifier is the pore modifier according to any one of claims 1-5 or the pore modifier prepared by any one of claims 6-11.

13. The concrete according to claim 12, characterized in that, The raw materials for the concrete include cement, fly ash, mineral powder, sand, limestone aggregate, water, and water-reducing agent.

14. The concrete according to claim 13, characterized in that, The raw materials for each cubic meter of concrete include 2-10 kg of the porosity modifier.

15. The application of the porosity modifier according to any one of claims 1-5, or the porosity modifier prepared by any one of claims 6-11, or the concrete according to any one of claims 12-14, characterized in that, The porosity modifier or the concrete is applied to building materials.

Images