Rural thermal insulation concrete and preparation method thereof

Abstract

The application discloses a kind of rural thermal insulation concrete and preparation method thereof, belong to building material technical field.The preparation raw materials of the rural thermal insulation concrete include cement: 100-120 parts, mineral powder: 20-40 parts, broken stone: 30-50 parts, expanded perlite: 30-50 parts, rice husk ash: 10-20 parts, additive: 0.5-2 parts, modified thermal phase change material: 20-50 parts by mass fraction.The preparation raw materials of the rural thermal insulation concrete also include water, and water-binder ratio is 0.4-0.6.The modified thermal phase change material is prepared by straw, steel slag, fly ash and fatty acid mixture.The rural thermal insulation concrete prepared by the application has excellent thermal insulation effect, high compressive strength, low thermal conductivity, strong durability and other characteristics.The rural thermal insulation concrete process involves the use of a large amount of solid waste materials, while reducing the use of cement, low cost, suitable for rural building applications.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building materials, and more particularly relates to a rural thermal insulation concrete and a preparation method thereof. BACKGROUND

[0002] In rural areas, self-built houses, agricultural greenhouses, and breeding farms commonly use traditional concrete or brick-concrete structures, which have poor thermal insulation performance. Specifically, in winter, the heat dissipates quickly due to the high thermal conductivity coefficient of ordinary concrete (about 1.5-2.0 W / (m·K)), leading to rapid loss of indoor heat and the need for heating equipment such as coal or electric heaters, which is energy-consuming and poses safety hazards. In summer, the walls have insufficient thermal insulation and strong heat storage, causing large fluctuations in indoor temperature and affecting the comfort of living. The existing thermal insulation solutions (such as external application of polystyrene boards or rock wool) require additional construction steps and material costs, which are burdensome for rural users.

[0003] Based on the above problems, various improved thermal insulation materials have appeared on the market, but there are still some problems: light aggregate concrete uses expanded perlite, ceramsite, or other light aggregates to replace part of the sandstone, reducing the density and thermal conductivity coefficient. However, light aggregates are expensive and have high water absorption, which can easily lead to a decrease in concrete strength. Foam concrete has closed pores introduced by chemical or physical foaming, which can significantly reduce the thermal conductivity coefficient, but its strength is extremely low and is only suitable for non-load-bearing filling structures. In addition, the cost of the foaming agent is high, and the process stability is poor, which can easily cause problems such as mold collapse and uneven pore structure. Composite thermal insulation materials mix phase change materials, aerogels, or organic thermal insulation particles into concrete. However, phase change materials (such as fatty acid mixtures) are expensive and have poor compatibility with cement; aerogels have low thermal conductivity but are extremely expensive and difficult to popularize; EPS particles are flammable, have a high risk coefficient, and have weak adhesion to cement, which can easily cause delamination and falling over long-term use. In addition, researchers have also tried to mix phase change materials into concrete by crushing agricultural waste such as rice husks and straws, in order to reduce the cost and thermal conductivity coefficient. However, a large amount of phase change materials (such as fatty acid mixtures) still need to be mixed, and the phase change materials can easily leak, affecting the performance of the material.

[0004] Therefore, it is of great significance to develop a low-cost, high-performance thermal insulation concrete for rural areas. SUMMARY

[0005] The purpose of the present application is to provide a rural thermal insulation concrete and a preparation method thereof, to solve the problems existing in the prior art and achieve the preparation of a low-cost, high-performance thermal insulation concrete for rural areas.

[0006] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0007] One of the technical solutions of the present application: provide a kind of rural thermal insulation concrete, by mass fraction, the preparation raw material of the rural thermal insulation concrete includes:

[0008] Cement: 100-120 parts, mineral powder: 20-40 parts, gravel: 30-50 parts, expanded perlite: 30-50 parts, rice husk ash: 10-20 parts, additive: 0.5-2 parts, modified thermal phase change material: 20-50 parts;

[0009] The preparation raw material of the rural thermal insulation concrete also includes water, and the water-binder ratio is 0.4-0.6;

[0010] The modified thermal phase change material is prepared by straw, steel slag, fly ash and fatty acid mixture.

[0011] Preferably, the preparation steps of the modified thermal phase change material include:

[0012] After mixing steel slag, straw and water, the modified mixture is obtained by reaction;

[0013] After mixing the modified mixture and fly ash, the composite carrier is obtained by calcination;

[0014] The fatty acid mixture is impregnated and loaded in the composite carrier to obtain the modified thermal phase change material.

[0015] Preferably, the particle size of the steel slag is ≤50 μm.

[0016] Preferably, the fatty acid mixture is stearic acid, palmitic acid and nanosilica;The mass ratio of stearic acid, palmitic acid and nanosilica is 8-9:0.5-1:0.1.

[0017] Preferably, the amount of steel slag is 10-20% of the mass of straw;And / or, the temperature of the reaction is 80-90 DEG C, and the time is 1-2 h.

[0018] Preferably, the mass ratio of fly ash and straw is 1:1-2;And / or, the temperature of the calcination is 600-700 DEG C, and the time is 40-80 min.

[0019] Preferably, the impregnation is vacuum impregnation;The temperature of the impregnation is 80-90 DEG C, the vacuum degree is-0.15 to-0.1 MPa, and the time is 1-2 h.

[0020] In the preparation process of the modified thermal phase change material, the amount of water in the present application is not limited, which can ensure that steel slag and straw can be mixed uniformly.

[0021] Preferably, the particle size of the mineral powder is 1-50 microns; the particle size of the gravel is 5-20 mm; the particle size of the expanded perlite is 1-3 mm; and the particle size of the rice husk ash is 0.01-0.1 mm.

[0022] Preferably, the additive includes a water-reducing agent and a foaming agent; and the mass ratio of the water-reducing agent to the foaming agent is 0.5-1:0.1-0.3.

[0023] The second technical scheme of the present application provides a preparation method of the rural thermal insulation concrete, comprising the following steps:

[0024] The preparation raw materials are mixed in a specified amount and cured to obtain the rural thermal insulation concrete.

[0025] Further, the humidity of the curing is greater than or equal to 95%, and the time is 28 days.

[0026] The technical mechanism of the present application is as follows:

[0027] The addition of the modified thermal insulation phase change material can significantly reduce the thermal conductivity of the prepared rural thermal insulation concrete (to 0.15-0.18 W / (m·K)), realize the temperature self-regulating performance of the concrete, enhance the thermal inertia of the concrete, and achieve a good delay effect of temperature fluctuation.

[0028] The reason why the modified thermal insulation phase change material can achieve the above effects is that:

[0029] First, the steel slag is used to hydrothermally modify the straw, and the free CaO and MgO in the steel slag provide an alkaline environment (pH>11) to promote the degradation of lignin in the straw, and the Fe2O3 in the steel slag can catalyze the oxidation and cracking of lignin to form a porous structure. Since lignin and fatty acid mixture have poor compatibility, the degradation of lignin can improve the loading capacity of the fatty acid mixture in the composite carrier, and also avoid the problem that lignin is easily decomposed at high temperature to affect the overall stability of the material. In addition, the hydrothermal modification of the straw by the steel slag can also form a porous structure, which also effectively improves the loading capacity of the fatty acid mixture.

[0030] Secondly, during the calcination process, the straw provides a macroporous structure, the fly ash contributes to a mesoporous structure, and the alkaline environment of the steel slag promotes the formation of micropores, so that the prepared composite carrier has a hierarchical pore (macropore, mesopore and micropore) structure, which significantly improves the loading effect of the fatty acid mixture, and the rich pore structure can ensure the effective loading of the fatty acid mixture and avoid the leakage of the fatty acid mixture. In addition, the Ca 2+ The fatty acid mixture can form an ionic bond with the Ca

[0031] The modified thermal insulation phase change material prepared by mixing straw, steel slag, fly ash and a fatty acid mixture under a specific process has excellent phase change effect, and when used in concrete, the temperature self-regulating performance of the concrete is achieved, the thermal inertia of the concrete is enhanced, and the temperature fluctuation is well delayed.

[0032] In addition, the modified thermal insulation phase change material can also improve the mechanical properties and durability of the concrete, CaO in the steel slag can promote hydration, thereby improving the compressive strength of the concrete; the modified thermal insulation phase change material realizes temperature self-regulation, reduces the ice expansion of water in the concrete, and improves the durability of the concrete.

[0033] The present application selects the admixture with specific ratio and specific particle size, which can significantly improve the mechanical properties and thermal insulation effect of the concrete.

[0034] Selecting the mineral powder: 20-40 parts, the particle size is 1-50 microns. The mineral powder with the selected grading and particle size can fill the pores and improve the durability. Selecting the gravel: 30-50 parts, the particle size is 5-20 mm. The gravel with the selected grading and particle size can play a role in skeleton support, and significantly improve the mechanical strength of the concrete. Selecting the expanded perlite: 30-50 parts, the particle size is 1-3 mm. The expanded perlite with the selected grading and particle size can significantly reduce the thermal conductivity, and at the same time, solve the problem of the addition of expanded perlite affecting the mechanical strength of the concrete. Selecting the rice husk ash: 10-20 parts, the particle size is 0.01-0.1 mm. The rice husk ash with the selected grading and particle size as active admixture can form secondary hydration, auxiliary cementitious material, and significantly improve the mechanical strength of the concrete. The use of the above-mentioned admixtures with specific ratio and particle size can effectively avoid the problem of poor mechanical properties of the concrete caused by the addition of expanded perlite, and significantly improve the mechanical properties and thermal insulation effect of the concrete.

[0035] The preparation process of the rural thermal insulation concrete disclosed in the present application involves the addition of a variety of waste materials, which can significantly reduce the cost.

[0036] The present application discloses the following technical effects:

[0037] The rural thermal insulation concrete prepared by the present application has excellent thermal insulation effect, high compressive strength, low thermal conductivity and strong durability, and can meet the demand of rural buildings and be suitable for wide application and promotion.

[0038] The preparation process of the rural thermal insulation concrete disclosed in the present application involves the use of a large amount of solid waste materials, and at the same time, the use of cement is reduced, which is low in cost and suitable for rural building application. DETAILED DESCRIPTION

[0039] The development of the rural thermal insulation concrete mainly has the following aspects:

[0040] Increasing demand for building energy efficiency: As the importance of building energy efficiency continues to grow, higher requirements are placed on the energy efficiency of rural buildings. Insulating concrete can meet the insulation requirements of rural housing and help achieve the goal of building energy efficiency.

[0041] Policy guidance for new rural construction: Large-scale renovation of old rural housing has become the mainstream. During the renovation process, new building materials and technologies are needed to improve the quality and performance of rural housing. Insulating concrete, as an energy-saving and environmentally friendly material, meets the requirements of new rural construction and has broad application prospects.

[0042] Current situation and demand of rural housing:

[0043] Poor insulation performance: In rural areas, old houses have mostly focused on meeting living functions, with poor insulation performance, resulting in cold in winter and hot in summer. In winter, relying on coal heating not only causes great damage to the environment but also increases the cost of life for farmers. In some areas, the heat in summer also requires houses to have good heat insulation performance to improve the comfort of living. Insulating concrete can effectively improve the insulation performance of rural housing, reduce energy consumption, and create a more comfortable living environment for farmers.

[0044] Building structure characteristics: Rural residences generally have fewer floors, typically 1-3 floors, with relatively low strength requirements for concrete, but high requirements for durability, insulation performance, and frost resistance. Insulating concrete has the appropriate strength grade, as well as good insulation performance, frost resistance, and durability, which can meet the structural and usage requirements of rural housing. In addition, the construction equipment for rural housing is relatively less, and the construction process of insulating concrete is relatively simple and operable, which can adapt to the construction conditions in rural areas.

[0045] Environmental protection and sustainable development needs:

[0046] Energy saving and emission reduction needs: Traditional rural building materials and construction methods have a greater impact on the environment, while the use of insulating concrete can reduce the consumption of energy such as coal and the emission of greenhouse gases such as carbon dioxide, which is beneficial to environmental protection and sustainable development.

[0047] Resource comprehensive utilization: Some insulating concrete can use industrial waste slag, waste materials, etc. as raw materials, such as fly ash, mineral powder, etc., achieving comprehensive utilization of resources, reducing the exploitation of natural resources, and reducing production costs. At the same time, it also helps to solve the problem of industrial waste disposal, with good economic value, environmental benefits, and social benefits.

[0048] Technical support: With the continuous progress of building material technology, the performance of thermal insulation concrete has been continuously improved and optimized. New thermal insulation concrete preparation process and construction technology are also developing, making the application of thermal insulation concrete more widely and conveniently, providing strong technical support for rural building energy saving.

[0049] Based on the above background, the present application provides a rural thermal insulation concrete with excellent thermal insulation effect, high compressive strength, low thermal conductivity and strong durability, which can meet the demand of rural buildings and is suitable for wide application. In addition, the use of a large amount of solid waste materials in the process of the rural thermal insulation concrete reduces the use of cement, has low cost and is suitable for rural building application.

[0050] The various exemplary embodiments of the present application will now be described in detail, which should not be considered as limiting the present application, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present application.

[0051] It should be understood that the terms described in the present application are only for describing the specific embodiments, and are not used to limit the present application. In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value within the stated range, and any other stated value or intermediate value within the stated range, is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are concerned. In the event of any conflict between the content of this specification and any document incorporated by reference, the content of this specification will control.

[0053] Many modifications and variations of the specific embodiments of the present application can be made without departing from the scope or spirit of the present application, which will be apparent to those skilled in the art. Other embodiments resulting from the combination of the present application will be apparent to those skilled in the art. The present application specification and examples are only exemplary.

[0054] As used herein, "comprise", "include", "have", "contain", and the like, are open-ended terms, i.e., meaning "including but not limited to".

[0055] It should be noted that the invention is not detailed, which is the conventional means of the art, and is not the focus of the invention.

[0056] The raw materials used in the following examples and comparative examples of the present application are commercially available products, and the source of the commercially available products does not affect the effect of the present application.

[0057] The room temperature involved in the present application is 25±5℃ unless otherwise specified.

[0058] Example 1

[0059] This embodiment provides the preparation of the modified thermal insulation phase change material, and the steps are as follows:

[0060] The steel slag is ground, sieved and dried to obtain steel slag with a particle size of ≤50μm; the treated steel slag and wheat straw (length ≤1mm) (the amount of steel slag is 15% of the mass of wheat straw) are mixed uniformly in water and reacted at 85℃ for 1h to obtain a modified mixture; the modified mixture and fly ash (the mass ratio of fly ash to wheat straw is 1:1) are mixed and calcined at 650℃ for 1h to obtain a composite carrier; prepare a fatty acid mixture: mix stearic acid, palmitic acid and nanosilica at a mass ratio of 8:0.5:0.1 at 80℃ to obtain a fatty acid mixture; first preheat the composite carrier to 80℃, then impregnate the fatty acid mixture into the composite carrier, the impregnation temperature is 80℃, the vacuum degree is-0.1MPa, and the time is 1h to obtain the modified thermal insulation phase change material.

[0061] This embodiment also provides the preparation of the thermal insulation concrete for rural use, and the steps are as follows:

[0062] Raw material preparation: cement: 100 parts, mineral powder (particle size 40μm): 20 parts, gravel (particle size 15mm): 30 parts, expanded perlite (particle size 2mm): 40 parts, rice husk ash (particle size 0.1mm): 15 parts, water reducing agent (lignosulfonate): 0.5 parts, foaming agent (sodium dodecyl sulfate): 0.3 parts, the modified thermal insulation phase change material prepared above: 40 parts.

[0063] Preparation process:

[0064] Mix the raw materials according to the above specified amount, place the mixture in a mold, and cure at room temperature and humidity ≥95% for 28d to obtain a concrete test block.

[0065] Example 2

[0066] This embodiment provides the preparation of the modified thermal insulation phase change material, and the steps are as follows:

[0067] The steel slag is ground, sieved and dried to obtain steel slag with a particle size of ≤50 μm; the treated steel slag and wheat straw (length ≤1 mm) (the amount of steel slag is 15% of the mass of wheat straw) are mixed uniformly in water and reacted at 90°C for 1 h to obtain a modified mixture; the modified mixture and fly ash (the mass ratio of fly ash to wheat straw is 1:1) are mixed and calcined at 600°C for 1.5 h to obtain a composite carrier; a fatty acid mixture is prepared: stearic acid, palmitic acid and nano-silicon dioxide are uniformly mixed at a mass ratio of 8.5:0.6:0.1 at 80°C to obtain a fatty acid mixture; the composite carrier is preheated to 80°C, and then the fatty acid mixture is impregnated in the composite carrier, the impregnation temperature is 85°C, the vacuum degree is -0.1 MPa, and the time is 1.5 h, to obtain a modified thermal insulation phase change material.

[0068] The example also provides preparation of the thermal insulation concrete for rural use, and the steps are as follows:

[0069] Raw material preparation: cement: 110 parts, mineral powder (particle size 15 μm): 35 parts, gravel (particle size 5 mm): 30 parts, expanded perlite (particle size 2 mm): 40 parts, rice husk ash (particle size 0.05 mm): 20 parts, water reducing agent (lignosulfonate): 0.5 parts, foaming agent (sodium dodecyl sulfate): 0.1 parts, and the modified thermal insulation phase change material prepared above: 25 parts.

[0070] Preparation process:

[0071] The raw materials are mixed according to the above specified amounts, and the mixture is placed in a mold and cured at room temperature and humidity ≥95% for 28 d to obtain a concrete test block.

[0072] Example 3

[0073] The example provides preparation of the modified thermal insulation phase change material, and the steps are as follows:

[0074] The steel slag is ground, sieved and dried to obtain steel slag with a particle size of ≤50 μm; the treated steel slag and wheat straw (length ≤1 mm) (the amount of steel slag is 15% of the mass of wheat straw) are mixed uniformly in water and reacted at 90°C for 1 h to obtain a modified mixture; the modified mixture and fly ash (the mass ratio of fly ash to wheat straw is 1:1) are mixed and calcined at 600°C for 1.5 h to obtain a composite carrier; a fatty acid mixture is prepared: stearic acid, palmitic acid and nano-silicon dioxide are uniformly mixed at a mass ratio of 8.5:0.6:0.1 at 80°C to obtain a fatty acid mixture; the composite carrier is preheated to 80°C, and then the fatty acid mixture is impregnated in the composite carrier, the impregnation temperature is 85°C, the vacuum degree is -0.1 MPa, and the time is 1.5 h, to obtain a modified thermal insulation phase change material.

[0075] The embodiment also provides preparation of the rural thermal insulation concrete, and the steps are as follows:

[0076] Raw material preparation: cement: 100 parts, mineral powder (particle size is 35 μm): 40 parts, gravel (particle size is 20 mm): 30 parts, expanded perlite (particle size is 3 mm): 50 parts, rice husk ash (particle size is 0.1 mm): 10 parts, water reducing agent (lignosulfonate): 0.5 parts, foaming agent (sodium dodecyl sulfate): 0.3 parts, and the modified thermal insulation phase change material prepared above: 25 parts.

[0077] Preparation process:

[0078] The raw materials are mixed according to the above specified amount, the mixture is placed in a mold, and cured at room temperature and humidity ≥ 95% for 28 days to obtain a concrete test block.

[0079] Comparative Example 1

[0080] The difference from Example 1 is that the "fatty acid mixture" in the preparation process of the modified thermal insulation phase change material is replaced by an equal amount of "paraffin", and the others are the same as Example 1.

[0081] Comparative Example 2

[0082] The difference from Example 1 is that the "steel slag" in the preparation process of the modified thermal insulation phase change material is replaced by an equal amount of "fly ash", and the others are the same as Example 1.

[0083] Comparative Example 3

[0084] The difference from Example 1 is that the preparation process of the modified thermal insulation phase change material is different, and the others are the same as Example 1.

[0085] Specifically:

[0086] The steel slag is ground, sieved and dried to obtain steel slag with a particle size of ≤ 50 μm; the treated steel slag, wheat straw (length ≤ 1 mm) (the amount of steel slag is 15% of the mass of wheat straw) and fly ash (the mass ratio of fly ash to wheat straw is 1:1) are mixed and calcined at 600 ℃ for 1.5 h to obtain a composite carrier; a fatty acid mixture is prepared: stearic acid, palmitic acid and nano silicon dioxide are uniformly mixed at a mass ratio of 8.5:0.6:0.1 at 80 ℃ to obtain a fatty acid mixture; the composite carrier is preheated to 80 ℃, and then the fatty acid mixture is impregnated in the composite carrier, the impregnation temperature is 85 ℃, the vacuum degree is -0.1 MPa, and the time is 1.5 h to obtain a modified thermal insulation phase change material.

[0087] Comparative Example 4

[0088] The difference from Example 1 is that the amount of mineral powder is adjusted to 60 parts, and the others are the same as Example 1.

[0089] Comparative Example 5

[0090] The difference from Example 1 is that the amount of crushed stone is adjusted to 10 parts, and the others are the same as Example 1.

[0091] Comparative Example 6

[0092] The difference from Example 1 is that the amount of expanded perlite is adjusted to 70 parts, and the others are the same as Example 1.

[0093] Comparative Example 7

[0094] The difference from Example 1 is that the amount of expanded perlite is adjusted to 15 parts, and the others are the same as Example 1.

[0095] Comparative Example 8

[0096] The difference from Example 1 is that the amount of rice husk ash is adjusted to 30 parts, and the others are the same as Example 1.

[0097] Performance test:

[0098] 1. Thermal conductivity and compressive strength test:

[0099] According to GB / T 10295-2008 "Determination of Steady-state Thermal Resistance and Related Properties of Thermal Insulation Materials by Heat Flow Meter Method", the thermal conductivity is measured using JTKD-1 rapid thermal conductivity instrument. The smaller the thermal conductivity, the better the thermal insulation performance of the thermal insulation concrete. The compressive strength test is carried out according to the test method and test equipment in GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete". The results are shown in Table 1.

[0100] Table 1 Thermal conductivity and compressive strength test results

[0101]

[0102] From Table 1, it can be seen that the concrete obtained in Comparative Example 1 (adjusting the type of phase change material) has no obvious decrease in compressive strength, but the thermal conductivity is obviously increased, and the heat insulation effect of the material is deteriorated. The concrete obtained in Comparative Example 2 (omitting the steel slag and supplementing with fly ash) has a significant decrease in compressive strength and a significant increase in thermal conductivity, which is due to the weakening of the hydration effect after omitting the steel slag addition, and the decrease in the number of micropores in the obtained modified thermal insulation phase change material, and the large amount of lignin in the straw significantly affects the loading effect of the phase change material (fatty acid mixture), and the phase change performance of the obtained modified thermal insulation phase change material is decreased. The concrete obtained in Comparative Example 3 (omitting the treatment step of the straw with the steel slag) has a significant decrease in compressive strength and a significant increase in thermal conductivity, which is due to the large amount of lignin in the straw significantly affecting the loading effect of the phase change material (fatty acid mixture), and the phase change performance of the obtained modified thermal insulation phase change material is decreased, and the lignin significantly increases to cause the decrease in the stability of the concrete and the decrease in the compressive strength. The concrete obtained in Comparative Examples 4-8 (adjusting the amount of each admixture) has a significant decrease in compressive strength and a significant increase in thermal conductivity compared with the concrete obtained in the examples. Among them, the concrete obtained in Comparative Example 6 has the most obvious decrease in compressive strength. Although the decrease in the addition of expanded perlite in Comparative Example 7 can alleviate the degree of decrease in compressive strength, it will cause the thermal conductivity to be obviously increased, which affects the heat insulation effect of the concrete.

[0103] 2. Freeze-thaw resistance test:

[0104] The test was carried out according to the standard of ASTM C666 (rapid freeze-thaw method). Test method: the concrete obtained in Examples 1-3 and Comparative Examples 1-8 was placed in an environment of -18℃ and 4℃ for alternating circulation for 300 times, and the time for each standing was 4h. The results are shown in Table 2.

[0105] Table 2: Freeze-thaw resistance test results

[0106]

[0107] From Table 2, it can be seen that the freeze-thaw resistance effect of the concrete obtained in the examples is significantly better than that of the comparative examples.

[0108] Each of the examples in the specification is described in a progressive manner, and each example focuses on the difference from other examples. The same or similar parts between each example can be referred to each other.

[0109] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the appended claims are intended to cover all such modifications that do not depart from the true spirit and scope of the application. Therefore, the application is not limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A thermal insulation concrete for rural use, characterized by, The preparation raw materials of the rural thermal insulation concrete include, by mass fraction: Cement: 100-120 parts, mineral powder: 20-40 parts, gravel: 30-50 parts, expanded perlite: 30-50 parts, rice husk ash: 10-20 parts, additive: 0.5-2 parts, and modified thermal phase change material: 20-50 parts; The preparation raw materials of the rural thermal insulation concrete further include water, and the water-binder ratio is 0.4-0.6; The modified thermal phase change material is prepared by mixing straw, steel slag, fly ash and fatty acid mixture; The preparation steps of the modified thermal phase change material include: Mixing the steel slag, straw and water and then reacting to obtain a modified mixture; Mixing the modified mixture and fly ash and then calcining to obtain a composite carrier; Impregnating the fatty acid mixture into the composite carrier to obtain the modified thermal phase change material.

2. The insulating concrete for rural use according to claim 1, characterized by, The particle size of the steel slag is ≤50 μm.

3. The insulating concrete for rural use according to claim 1, characterized by, The fatty acid mixture is stearic acid, palmitic acid and nanosilica, and the mass ratio of the stearic acid, palmitic acid and nanosilica is 8-9:0.5-1:0.

1.

4. The insulating concrete for rural use according to claim 1, characterized by, The amount of the steel slag is 10-20% of the mass of the straw; and / or, the reaction temperature is 80-90 ℃, and the reaction time is 1-2 h.

5. The insulating concrete for rural use according to claim 1, characterized by, The mass ratio of the fly ash and straw is 1:1-2; and / or, the calcination temperature is 600-700 ℃, and the calcination time is 40-80 min.

6. The insulating concrete for rural use according to claim 1, characterized by, The impregnation is vacuum impregnation; the impregnation temperature is 80-90 ℃, the vacuum degree is -0.15 to -0.1 MPa, and the impregnation time is 1-2 h.

7. The insulating concrete for rural use according to claim 1, characterized by, The particle size of the mineral powder is 1-50 μm; the particle size of the gravel is 5-20 mm; the particle size of the expanded perlite is 1-3 mm; and the particle size of the rice husk ash is 0.01-0.1 mm.

8. The insulating concrete for rural use according to claim 1, characterized by, The additive includes water reducing agent and foaming agent, and the mass ratio of the water reducing agent and foaming agent is 0.5-1:0.1-0.

3.

9. The method of preparing insulating concrete for rural use according to any one of claims 1 to 8, characterized in that, The method includes the following steps: Mixing the preparation raw materials in a specified amount and curing to obtain the rural thermal insulation concrete.

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