Self-breathing clear water concrete and a preparation method thereof

Abstract

This application relates to the field of concrete technology, specifically disclosing a self-breathing fair-faced concrete and its preparation method. This application incorporates filler fibers and pre-wetted expanded clay aggregate into the fair-faced concrete formulation, resulting in fair-faced concrete with a high capillary content. The pore structure of the capillaries and expanded clay aggregates together improves the migration efficiency of water in the fair-faced concrete, enabling it to possess excellent drainage properties and more fully meet the requirements of "self-breathing" fair-faced concrete. The fair-faced concrete of this application can regulate temperature, which is beneficial for maintaining a constant temperature environment indoors. Furthermore, its ability to regulate humidity through water absorption and release further enhances the suitability of the indoor environment.

Description

Technical Field

[0001] This application relates to the field of concrete technology, and more specifically, to a self-breathing clear water concrete and its preparation method. Background Technology

[0002] Fair-faced concrete refers to concrete where the natural surface of the concrete after molding is used as the finish. In recent years, with the advancement of concrete technology, the application of fair-faced concrete is no longer limited to traditional large-scale projects such as roads, bridges, and airports; it has begun to be used as non-load-bearing components in some civil buildings. In fair-faced concrete, "self-breathing" usually refers to its ability to absorb and drain water after hardening, which helps regulate the indoor environment of buildings. To achieve this property, the traditional fair-faced concrete formula needs to be improved.

[0003] One type of fair-faced concrete uses the following mix proportions: 410 kg cement, 800 kg sand, 960 kg aggregate, 193 kg water, and 2.5 kg water-reducing agent. The measured slump of the concrete mixture prepared according to this mix proportion is 185 mm. The concrete mixture is produced by first dry mixing, then adding water and water-reducing agent. The dry mixing time is 30 seconds, and the mixing time after adding water and water-reducing agent is 150 seconds.

[0004] Regarding the aforementioned technologies, the inventors believe that although the production of fair-faced concrete can be achieved by following the methods described in the relevant technologies, and fair-faced concrete can also achieve a certain water absorption capacity, the drainage performance of such fair-faced concrete is relatively poor, making it difficult to fully meet the requirements of "self-breathing" fair-faced concrete. Moreover, the temperature regulation effect of fair-faced concrete is also relatively limited. Summary of the Invention

[0005] In related technologies, fair-faced concrete has relatively poor drainage performance, making it difficult to fully meet the requirements of "self-breathing" fair-faced concrete. Furthermore, fair-faced concrete has limited temperature regulation capabilities. To address this deficiency, this application provides a self-breathing fair-faced concrete and its preparation method.

[0006] In the first aspect, this application provides a self-breathing, water-resistant concrete, which adopts the following technical solution:

[0007] A self-breathing fair-faced concrete, wherein the fair-faced concrete is poured from a concrete mix, the concrete mix comprising the following components by weight: 410-420 parts silicate cement, 800-820 parts fine aggregate, 760-780 parts coarse aggregate, 8-12 parts filler fiber, 200-220 parts pre-wetted ceramsite, 193-195 parts water, and 2.5-2.7 parts water-reducing agent; the fine aggregate includes phase change energy storage aggregate accounting for 10-15% of the total weight of fine aggregate, the phase change energy storage aggregate being expanded perlite particles adsorbed with lauric acid and lauryl alcohol; the pre-wetted ceramsite is sintered ceramsite that has absorbed water to constant weight, the sintered ceramsite including clay ceramsite, the saturated water absorption rate of the clay ceramsite being 8-10%.

[0008] By adopting the above technical solution, compared with related technologies, this application adds pre-wetted expanded clay aggregate and filler fibers to the concrete mixture. The pre-wetted expanded clay aggregate continuously releases moisture during the hardening process of the concrete mixture, increasing the water-cement ratio and free water content. Due to the increased free water content, the total number of capillaries formed in the fair-faced concrete increases accordingly. The addition of filler fibers hinders the volume shrinkage of the concrete mixture, reducing capillary collapse and resulting in fair-faced concrete with a higher capillary content. The pore structure of the capillaries and expanded clay aggregate together enhances the migration efficiency of water in the fair-faced concrete, enabling it to have good drainage and more fully meet the requirements of "self-breathing" fair-faced concrete.

[0009] Furthermore, this application preferably includes phase change energy storage aggregate in the fine aggregate composition. Lauric acid and lauryl alcohol in the phase change energy storage aggregate can undergo a phase change upon heating, absorbing heat, and then releasing heat when the molten lauric acid and lauryl alcohol solidify. Through the use of phase change energy storage aggregate, the fair-faced concrete of this application can regulate temperature, which is beneficial for maintaining a constant temperature environment inside buildings. In addition, it can regulate humidity through water absorption and release, thereby improving the suitability of the indoor environment.

[0010] Preferably, the sintered ceramsite further includes sludge ceramsite, wherein the weight of the sludge ceramsite accounts for 10-40% of the total weight of the sintered ceramsite, and the sludge ceramsite is prepared according to the following method:

[0011] (1) Mix dewatered sludge, construction waste and water, and then let it stand for aging to obtain aged material; the ratio of the amount of dewatered sludge to construction waste is (0.6-1):1, and the loss on ignition of the dewatered sludge is 32-54%;

[0012] (2) Granulate the aged material to obtain raw material balls, dry the raw material balls, and then calcine the dried raw material balls to constant weight to obtain sludge ceramsite.

[0013] By adopting the above technical solution, this application adds sludge ceramsite in addition to clay ceramsite. Conventional clay ceramsite has a structure and physical properties similar to clay bricks, with a water absorption rate of mostly 8-10%. However, in the sludge ceramsite of this application, since dewatered sludge has a higher loss on ignition, the prepared sludge ceramsite can have better water absorption performance than clay ceramsite, thereby more fully increasing the free water content in the concrete mix, and thus obtaining fair-faced concrete with higher capillary content and better drainage performance.

[0014] Preferably, the loss on ignition of the dewatered sludge is 46-54%.

[0015] By adopting the above technical solution, the loss on ignition of dewatered sludge was optimized, which helps to improve the drainage performance of fair-faced concrete.

[0016] Preferably, the ratio of the amount of dewatered sludge to construction waste is (0.8-1):1.

[0017] By adopting the above technical solution, the optimal ratio of dewatered sludge to construction waste was selected, which helps to improve the drainage performance of fair-faced concrete.

[0018] Preferably, the sludge ceramsite accounts for 28-40% of the total weight of the sintered ceramsite.

[0019] By adopting the above technical solution, the weight ratio of sludge ceramsite in the total weight of sintered ceramsite was optimized, which helps to improve the drainage performance of fair-faced concrete.

[0020] Preferably, the filling fiber is an acrylic fiber or a modified acrylic fiber, wherein the modified acrylic fiber is an acrylic fiber with carboxyl groups on its surface.

[0021] By adopting the above technical solution, this application has optimized the type of filler fiber. Compared with acrylic fiber, the carboxyl groups on the surface of modified acrylic fiber enable the modified acrylic fiber to have better hygroscopicity, which is beneficial to promoting the migration of water in fair-faced concrete. At the same time, the carboxyl groups can also enhance the bonding force between the filler fiber and cement paste, which helps to reduce the shrinkage generated during the hardening process of fair-faced concrete and helps to reduce the collapse of capillary pores. Therefore, modified acrylic fiber is more conducive to improving the drainage performance of fair-faced concrete.

[0022] Preferably, the modified acrylic fiber is prepared by the following method: sodium hydroxide is added to a mixed solution of water and ethanol to obtain a modified solution with a sodium hydroxide mass fraction of 2-6%; acrylic fiber is immersed in the modified solution, and then heated in a constant temperature water bath at 80-95°C. After the water bath heating, the modified solution is adjusted to acidity using acetic acid. Then the acrylic fiber is taken out, dried, and cut to obtain the modified acrylic fiber.

[0023] By adopting the above technical solution, this application first performs alkaline hydrolysis on acrylic fibers to convert the acrylonitrile groups into sodium carboxylate groups, and then converts the sodium carboxylate groups into carboxyl groups through the acidification of acetic acid, thereby obtaining modified acrylic fibers.

[0024] Preferably, the mass fraction of sodium hydroxide in the modified solution is 4-6%.

[0025] By adopting the above technical solution, the mass fraction of sodium hydroxide in the modified solution was optimized, which is beneficial to the full hydrolysis of acrylic fibers, increases the total amount of carboxyl groups on the surface of modified acrylic fibers, and improves the drainage performance of fair-faced concrete.

[0026] Preferably, the temperature of the constant temperature water bath is 88-95℃.

[0027] By adopting the above technical solution, the optimal temperature conditions for constant temperature water bath heating are selected, which is conducive to the full hydrolysis of acrylic fibers, increases the total amount of carboxyl groups on the surface of modified acrylic fibers, and improves the drainage performance of fair-faced concrete.

[0028] Secondly, this application provides a method for preparing self-breathing water-resistant concrete, which adopts the following technical solution.

[0029] A method for preparing self-breathing fair-faced concrete includes the following steps:

[0030] (1) Silicate cement, fine aggregate, coarse aggregate, filler fiber and pre-wetted ceramsite are mixed to obtain dry material; water-reducing agent, defoamer and water are mixed to obtain admixture solution;

[0031] (2) Mix the admixture solution and dry material, and after stirring, obtain a concrete mixture. Pour the concrete mixture and after curing, obtain self-breathing clear water concrete.

[0032] By adopting the above technical solution, this application first prepared dry materials and admixture solutions separately, and then mixed them to ensure that the water-reducing agent was fully dispersed, thus obtaining a concrete mix. The concrete mix was then used to pour self-breathing clear water concrete.

[0033] In summary, this application has the following beneficial effects:

[0034] 1. This application incorporates filler fibers and pre-wetted expanded clay aggregate into the fair-faced concrete formulation, resulting in fair-faced concrete with a high capillary content. The pore structure of the capillaries and expanded clay aggregates together improves the migration efficiency of water in the fair-faced concrete, enabling it to possess excellent drainage properties and more fully meet the requirements of "self-breathing" fair-faced concrete. The fair-faced concrete of this application can regulate temperature, which is beneficial for maintaining a constant temperature environment indoors. Furthermore, its ability to regulate humidity through water absorption and release further enhances the suitability of the indoor environment.

[0035] 2. The preferred sintered ceramsite in this application also includes sludge ceramsite. Sludge ceramsite has better water absorption than clay ceramsite, and can release more water in concrete mixes, thereby promoting the formation of capillaries, enhancing the migration efficiency of water in fair-faced concrete, helping to improve the drainage performance of fair-faced concrete, and enabling fair-faced concrete to better play its "self-breathing" role. Detailed Implementation

[0036] The present application will be further described in detail below with reference to the embodiments, preparation examples and comparative examples. The raw materials involved in the present application can all be obtained commercially.

[0037] Preparation example of sludge ceramsite

[0038] The following explanation uses Preparation Example 1 as an example.

[0039] Preparation Example 1

[0040] In this preparation example, the sludge ceramsite was prepared according to the following method:

[0041] (1) Mix dewatered sludge, construction waste and water, and then let it stand for aging to obtain aged material; the ratio of dewatered sludge to construction waste is 0.6:1, and the loss on ignition of dewatered sludge is 32%.

[0042] (2) Granulate the aged material to obtain raw material balls, dry the raw material balls at 105℃, and then place the dried raw material balls in a calcining equipment and heat them to 950℃ at a rate of 4℃ / min. Keep them at 950℃ for 1 hour and then cool them naturally to obtain sludge ceramsite with an average particle size of 6.4mm.

[0043] As shown in Table 1, the difference between the preparation examples 1-5 lies in the different loss on ignition of the dewatered sludge.

[0044] Table 1 Loss on Ignition of Dewatered Sludge

[0045]

[0046]

[0047] Preparation Examples 6-9

[0048] As shown in Table 2, the difference between Preparation Examples 6-9 and Preparation Example 5 is that the ratio of dewatered sludge to construction waste is different.

[0049] Table 2. Ratio of dewatered sludge to construction waste usage

[0050] sample Dewatered sludge: construction waste Preparation Example 5 0.6:1 Preparation Example 6 0.7:1 Preparation Example 7 0.8:1 Preparation Example 8 0.9:1 Preparation Example 9 1:1

[0051] Preparation example of modified acrylic fiber

[0052] The following explanation uses Preparation Example 10 as an example.

[0053] Preparation Example 10

[0054] In this preparation example, the modified acrylic fiber was prepared according to the following method:

[0055] Sodium hydroxide was added to a mixed solution of water and ethanol (the weight ratio of ethanol to water was 1:10) to obtain a modified solution with a sodium hydroxide mass fraction of 2%. Continuous acrylic fibers with an average diameter of 17 μm were immersed in the modified solution at a bath ratio of 1:30, and then heated in a constant temperature water bath at 80 °C for 2 hours. After heating in the water bath, the pH of the modified solution was adjusted to 6 using acetic acid. The continuous acrylic fibers were then removed, dried, and cut to obtain modified acrylic fibers with an average length of 12 mm.

[0056] Preparation Examples 11-14

[0057] As shown in Table 3, the difference between Preparation Examples 11-14 and Preparation Example 10 is that the mass fraction of sodium hydroxide in the modified solution is different.

[0058] Table 3 Mass fraction of sodium hydroxide

[0059] sample Sodium hydroxide mass fraction / % Preparation Example 10 2 Preparation Example 11 3 Preparation Example 12 4 Preparation Example 13 5 Preparation Example 14 6

[0060] Preparation Examples 15-18

[0061] As shown in Table 4, the difference between Preparation Examples 15-18 and Preparation Example 14 is that the heating temperature in the constant temperature water bath is different.

[0062] Table 4 Temperature of Constant Temperature Water Bath Heating

[0063] sample Water bath temperature / ℃ Preparation Example 14 80 Preparation Example 15 84 Preparation Example 16 88 Preparation Example 17 91 Preparation Example 18 95

[0064] Example of phase change energy storage aggregate preparation

[0065] Preparation Example 19

[0066] In this preparation example, the phase change energy storage aggregate is prepared according to the following method:

[0067] Under vacuum conditions, a bulk density of 90 kg / m³ is achieved.3 Expanded perlite with a water absorption rate of 480% was mixed with a eutectic mixture of lauric acid and lauryl alcohol (the weight ratio of lauryl alcohol to lauric acid was 37:63). After 1 hour, the mixture was removed and cooled to obtain phase change energy storage aggregate. In the phase change energy storage aggregate of this preparation example, the weight of the eutectic mixture was 3.08 times the weight of the expanded perlite.

[0068] Example

[0069] Examples 1-5

[0070] The following description uses Example 1 as an example.

[0071] Example 1

[0072] This embodiment provides a self-breathing clear water concrete, comprising the following components: 410 kg of silicate cement, 800 kg of fine aggregate, 760 kg of coarse aggregate, 8 kg of filler fiber, 200 kg of pre-wetted ceramsite, 193 kg of water, 2.5 kg of water-reducing agent, and 0.4 kg of defoamer. The silicate cement is P.O42.5 silicate cement. The fine aggregate includes river sand with a fineness modulus of 2.7 and the phase change energy storage aggregate of Preparation Example 19, with the phase change energy storage aggregate accounting for 10% of the total weight of the fine aggregate. The coarse aggregate is 5-25 mm continuously graded crushed stone. The filler fiber is acrylic fiber with an average diameter of 17 μm and an average length of 12 mm. The pre-wetted ceramsite is obtained by soaking sintered ceramsite in water until it becomes saturated with water. The sintered ceramsite is clay ceramsite with an average particle size of 6.4 mm and a saturated water absorption rate of 8%. The defoamer is SITREN AirVoid 321, and the water-reducing agent has a water reduction rate of 18%.

[0073] In this embodiment, the self-breathing water-resistant concrete is prepared according to the following steps:

[0074] (1) Mix silicate cement, fine aggregate, coarse aggregate, filler fiber and pre-wetted ceramsite, and dry mix for 30 seconds to obtain dry material; mix water-reducing agent, defoamer and water to obtain admixture solution;

[0075] (2) Mix the admixture solution and dry material, and after stirring for 150 seconds, a concrete mixture is obtained. The concrete mixture is poured and vibrated to remove bubbles during the pouring process. After curing, self-breathing clear water concrete is obtained.

[0076] As shown in Table 5, the main difference between Examples 1-5 lies in the different raw material proportions of the self-breathing concrete. Additionally, the saturated water absorption rates of the clay ceramsite used in Examples 1-5 are 8%, 8.5%, 9%, 9.5%, and 10%, respectively; and the percentage of phase change energy storage aggregate by weight to the total weight of fine aggregate in Examples 1-5 is 10%, 11.2%, 12.4%, 13.9%, and 15%, respectively.

[0077] Table 5. Raw material proportions for self-breathing fair-faced concrete.

[0078]

[0079] Example 6

[0080] The difference between this embodiment and Embodiment 5 is that the sintered ceramsite is a mixture of clay ceramsite and sludge ceramsite from Preparation Example 1, wherein the sludge ceramsite accounts for 10% of the total weight of the sintered ceramsite.

[0081] As shown in Table 6, the difference between Examples 6-14 lies in the different preparation methods of the sludge ceramsite.

[0082] Table 6 Examples of sludge ceramsite preparation

[0083] sample Preparation Example Example 6 Preparation Example 1 Example 7 Preparation Example 2 Example 8 Preparation Example 3 Example 9 Preparation Example 4 Example 10 Preparation Example 5 Example 11 Preparation Example 6 Example 12 Preparation Example 7 Example 13 Preparation Example 8 Example 14 Preparation Example 9

[0084] Examples 15-18

[0085] As shown in Table 7, the difference between Examples 15-18 and Example 14 is that the weight of sludge ceramsite accounts for a different percentage of the total weight of sintered ceramsite (hereinafter referred to as the sludge ceramsite percentage).

[0086] Table 7. Proportion of Sludge Ceramsite

[0087] sample Sludge ceramsite percentage Example 14 10 Example 15 19 Example 16 28 Example 17 34 Example 18 40

[0088] Example 19

[0089] The difference between this preparation example and Example 18 is that the filling fiber is the modified acrylic fiber of Preparation Example 10.

[0090] As shown in Table 8, the difference between Examples 19-27 is that the preparation examples of the modified acrylic fibers are different.

[0091] Table 8 Examples of Preparation of Modified Acrylic Fibers

[0092] sample Preparation Example Example 19 Preparation Example 10 Example 20 Preparation Example 11 Example 21 Preparation Example 12 Example 22 Preparation Example 13 Example 23 Preparation Example 14 Example 24 Preparation Example 15 Example 25 Preparation Example 16 Example 26 Preparation Example 17 Example 27 Preparation Example 18

[0093] Comparative Example

[0094] Comparative Example 1

[0095] In this comparative example, the silicate cement is P.O42.5 silicate cement, the fine aggregate is river sand with a fineness modulus of 2.7, the coarse aggregate is 5-25mm continuously graded crushed stone, and the water reduction rate of the water reducing agent is 18%.

[0096] This comparative example provides a fair-faced concrete with the following mix proportions: 410 kg cement, 800 kg sand, 960 kg aggregate, 193 kg water, and 2.5 kg water-reducing agent. The fair-faced concrete of this comparative example is first dry-mixed, then water and water-reducing agent are added. The dry-mixing time is 30 seconds, and the mixing time after adding water and water-reducing agent is 150 seconds. The resulting concrete mixture is then poured, vibrated to remove air bubbles, and cured to obtain fair-faced concrete.

[0097] Comparative Example 2

[0098] The difference between this comparative example and Example 1 is that the pre-wetted ceramsite is replaced with sintered ceramsite that has not undergone water soaking treatment.

[0099] Comparative Example 3

[0100] The difference between this comparative example and Example 1 is that the concrete mix does not include filler fibers.

[0101] Performance testing methods

[0102] Referring to the permeability coefficient test method recorded in "DL / T 5303—2013 Test Procedure for Hydraulic Plastic Concrete", the permeability coefficient of the fair-faced concrete in each embodiment and comparative example was tested. Then, taking Comparative Example 1 as the benchmark, the ratio between the permeability coefficient of each embodiment and comparative example and the permeability coefficient of Comparative Example 1 was calculated. This ratio was recorded as the relative permeability coefficient. The results are shown in Table 9.

[0103] Table 9 Relative Permeability Coefficients

[0104] sample Relative permeability coefficient / % sample Relative permeability coefficient / % Example 1 134.2 Example 16 155.4 Example 2 134.7 Example 17 159.8 Example 3 135.1 Example 18 163.4 Example 4 135.2 Example 19 164.9 Example 5 135.6 Example 20 165.7 Example 6 136.9 Example 21 167.1 Example 7 138.2 Example 22 168.2 Example 8 140.4 Example 23 169.9 Example 9 142.3 Example 24 170.2 Example 10 145.9 Example 25 170.7 Example 11 146.4 Example 26 171.5 Example 12 147.1 Example 27 172.4 Example 13 148.5 Comparative Example 1 100.0 Example 14 149.6 Comparative Example 2 103.5 Example 15 152.1 Comparative Example 3 108.2

[0105] As can be seen from Examples 1-5 and Comparative Example 1, and in conjunction with Table 9, the relative permeability coefficients measured in Examples 1-5 are all greater than those in Comparative Example 1. This indicates that water permeates more easily in the fair-faced concrete of this application, giving it good water conductivity and enabling it to more fully meet the requirement of "self-breathing." Furthermore, because the fair-faced concrete of this application incorporates phase change energy storage aggregates, it can regulate temperature, which is beneficial for maintaining a constant temperature environment inside buildings. In addition, it can regulate humidity through water absorption and release, thereby improving the suitability of the indoor environment.

[0106] Combining Example 1 and Comparative Example 2 with Table 9, it can be seen that the washing permeability coefficient measured in Example 1 is greater than that in Comparative Example 2. This indicates that when the expanded clay aggregate is not soaked in water, although the porous structure of the expanded clay aggregate itself can improve the water conduction effect, the absorption of water by the expanded clay aggregate will lead to a decrease in the actual water-cement ratio of the concrete mixture and a reduction in the free water content, which will affect the formation of capillaries. Therefore, the water conductivity of fair-faced concrete is poor and it is difficult to fully meet the requirements of "self-breathing".

[0107] Combining Example 1 and Comparative Example 3 with Table 9, it can be seen that the washing permeability coefficient measured in Example 1 is greater than that in Comparative Example 3. This indicates that when there is a lack of filler fibers, the shrinkage of concrete will cause the capillary to collapse, which is not conducive to the full formation of capillary. Therefore, the water conductivity of fair-faced concrete is poor and it is difficult to fully meet the requirements of "self-breathing".

[0108] Combining Examples 5 and 6-10 with Table 9, it can be seen that the relative permeability coefficients measured in Examples 6-10 are all greater than those in Example 5, indicating that sludge ceramsite has better water absorption performance than clay ceramsite. Selecting sludge ceramsite as the sintering ceramsite can more fully increase the free water content in the concrete mix, thereby obtaining fair-faced concrete with higher capillary content and better drainage performance. When the loss on ignition of dewatered sludge is 46-54%, the water permeability in fair-faced concrete is good, allowing fair-faced concrete to more fully meet the requirement of "self-breathing".

[0109] As can be seen from Examples 10-14 and Table 9, when the ratio of dewatered sludge to construction waste is (0.8-1):1, the water permeability in fair-faced concrete is better, which allows fair-faced concrete to more fully meet the requirements of "self-breathing".

[0110] As can be seen from Examples 14-18 and Table 9, when the weight of sludge ceramsite accounts for 28-40% of the total weight of sintered ceramsite, the water permeability in fair-faced concrete is better, which allows fair-faced concrete to more fully meet the requirements of "self-breathing".

[0111] Combining Examples 18 and 19-23 with Table 9, it can be seen that the relative permeability coefficients measured in Examples 19-23 are all greater than those in Example 18. This indicates that the carboxyl groups on the surface of the modified acrylic fibers enable them to have better hygroscopicity than regular acrylic fibers, which is beneficial for promoting the migration of water in fair-faced concrete. Simultaneously, the carboxyl groups also enhance the bonding force between the filler fibers and cement paste, helping to reduce shrinkage during the hardening process of fair-faced concrete and reducing capillary collapse. Therefore, the modified acrylic fibers are more conducive to improving the drainage performance of fair-faced concrete. When the mass fraction of sodium hydroxide in the modification solution is 4-6%, the water permeability in fair-faced concrete is better, allowing the fair-faced concrete to more fully meet the requirement of "self-breathing".

[0112] As can be seen from Examples 23-27 and Table 9, when the temperature of the constant temperature water bath is 88-95℃, the water permeability in fair-faced concrete is good, which allows fair-faced concrete to more fully meet the requirements of "self-breathing".

[0113] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An autoclaved aerated concrete, characterized in that, The fair-faced concrete is poured from a concrete mix, which comprises the following components by weight: 410-420 parts silicate cement, 800-820 parts fine aggregate, 760-780 parts coarse aggregate, 8-12 parts filler fiber, 200-220 parts pre-wetted ceramsite, 193-195 parts water, and 2.5-2.7 parts water-reducing agent. The fine aggregate includes phase change energy storage aggregate accounting for 10-15% of the total weight of fine aggregate. The phase change energy storage aggregate is expanded perlite particles adsorbed with lauric acid and lauryl alcohol. The pre-wetted ceramsite is sintered ceramsite that has absorbed water to constant weight. The sintered ceramsite includes clay ceramsite, and the saturated water absorption rate of the clay ceramsite is 8-10%. The filler fiber is selected from acrylic fiber or modified acrylic fiber. The modified acrylic fiber is acrylic fiber with carboxyl groups on its surface.

2. The self-breathing clear concrete according to claim 1, wherein, The sintered ceramsite also includes sludge ceramsite, the weight of which accounts for 10-40% of the total weight of the sintered ceramsite. The sludge ceramsite is prepared according to the following method: (1) Mix dewatered sludge, construction waste and water, and then let it stand for aging to obtain aged material; the ratio of the amount of dewatered sludge to construction waste is (0.6-1):1, and the loss on ignition of the dewatered sludge is 32-54%; (2) Granulate the aged material to obtain raw material balls, dry the raw material balls, and then calcine the dried raw material balls to constant weight to obtain sludge ceramsite.

3. The self-breathing fair-faced concrete according to claim 2, characterized in that, The loss on ignition of the dewatered sludge is 46-54%.

4. The self-breathing fair-faced concrete according to claim 3, characterized in that, The ratio of the amount of dewatered sludge to construction waste is (0.8-1):

1.

5. The self-breathing fair-faced concrete according to claim 4, characterized in that, The weight of the sludge ceramsite accounts for 28-40% of the total weight of the sintered ceramsite.

6. The self-breathing fair-faced concrete according to claim 1, characterized in that, The modified acrylic fiber is prepared by adding sodium hydroxide to a mixed solution of water and ethanol to obtain a modified solution with a sodium hydroxide mass fraction of 2-6%. Acrylic fibers are immersed in a modification solution and then heated in a constant temperature water bath at 80-95℃. After water bath heating, acetic acid is used to adjust the modification solution to acidity. The acrylic fibers are then removed, dried, and cut to obtain modified acrylic fibers.

7. The self-breathing fair-faced concrete according to claim 6, characterized in that, The modified solution contains 4-6% sodium hydroxide by mass.

8. The self-breathing fair-faced concrete according to claim 7, characterized in that, The temperature of the constant temperature water bath is 88-95℃.

9. The method for preparing self-breathing fair-faced concrete according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Silicate cement, fine aggregate, coarse aggregate, filler fiber and pre-wetted ceramsite are mixed to obtain dry material; water-reducing agent, defoamer and water are mixed to obtain admixture solution; (2) Mix the admixture solution and dry material, and after stirring, obtain concrete mix. Pour the concrete mix and after curing, obtain self-breathing clear water concrete.

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