Solid waste-based phase change foam concrete, preparation method and application thereof

Abstract

The application discloses solid waste-based phase change foam concrete and a preparation method and application thereof, relates to the technical field of green and energy-saving building materials, and aims to solve the problems of high production cost, poor stability, high production and application requirements, poor season adaptability and the like of phase change wall materials, and the solid waste-based phase change foam concrete comprises the following components in the following proportions by weight: 30-37 parts of 42.5-grade ordinary portland cement, 8-12 parts of slag powder, 8-13 parts of brick slag, 1.0-1.5 parts of basalt fiber, 2-3 parts of paraffin with a phase change temperature of 28 DEG C, 2-4 parts of paraffin with a phase change temperature of 18 DEG C, 0.01-0.02 parts of fatty alcohol polyoxyethylene ether, 0.0025-0.005 parts of water-soluble polyvinyl alcohol, 2.5-3.5 parts of hydrogen peroxide, 0.3-0.5 parts of manganese dioxide, 20-27 parts of water, 5-8 parts of gypsum, 1.0-1.5 parts of superabsorbent resin and 0.1-0.3 parts of a surfactant. The application can meet the building energy-saving requirements in high-temperature and low-temperature environments and prolong the effective period of the technical functions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of green energy-saving building materials, and particularly relates to a solid waste-based phase change foam concrete as well as a preparation method and application thereof. BACKGROUND

[0002] A phase change material refers to a material that changes state at a phase change temperature and provides latent heat. This process is called a phase change process, and the phase change material absorbs or releases a large amount of heat energy in this process. Solid waste resource utilization has been an engineering and technical problem worldwide. Among them, building solid waste such as brick slag has large emission and poor uniformity, and its crushing into aggregate, powder or direct use for backfilling has great limitations, and its own characteristics have not been fully utilized. Industrial solid waste such as slag and flue gas desulfurization gypsum has gradually lost its economic advantage in existing technology, and still has considerable emission pressure, and urgently needs new resource utilization technology. With the continuous development of modern building industrialization, the performance requirements of wall materials in the construction industry are increasing. Wall materials are the main component of building maintenance structures, and their use is large and important for building energy saving. Phase change wall materials have become the focus of the industry. The use of solid waste materials in phase change wall materials through new technical means can effectively alleviate the emission pressure of solid waste and improve the energy saving and environmental protection of buildings, which will become one of the development trends of the construction industry.

[0003] In the prior art, phase change wall materials are more researched than applied, and have problems such as high cost, poor stability, high production and application requirements, and poor seasonal applicability. For example, Chinese patent application CN201811568070.1 provides a sunlight greenhouse north wall, and its content only relates to the structure design and heat insulation principle of the heat preservation wall body using phase change blocks. Chinese patent application CN202210444404.4 provides a phase change energy storage concrete wall for heat preservation and insulation, which is composed of an outer phase change wallboard layer, a foam concrete heat preservation layer, an inner phase change wallboard layer and a plaster mortar layer in sequence. The outer phase change wallboard layer and the inner phase change wallboard layer are prepared by adding octadecane paraffin phase change microcapsules and hexadecane paraffin phase change microcapsules directly into conventional concrete raw materials to prepare phase change concrete, and the foam concrete heat preservation layer does not involve phase change materials. However, the phase change microcapsules used are too expensive, and the wall body is a multi-layer composite wall body, which has problems such as complex structure process and large self-weight. The use of phase change materials with different phase change temperatures inside and outside the wall body only considers the environment where the indoor temperature is low and the outdoor temperature is high, and the phase change process has no functional applicability in all seasons.

[0004] In the paper "Experimental Study on Phase Change Paraffin Emulsion Foam Concrete" (Chen Zhijun et al., "Silicate Bulletin", 2023, No. 42 (5), 1623-1629+1649), a phase change paraffin water-based dispersion emulsion is prepared and introduced into the chemical foaming process to produce phase change foam concrete. It uses a paraffin with a phase change temperature of 28-30℃, and the paraffin is in the form of emulsion during the preparation of foam concrete. According to the research results, the prepared phase change foam concrete is used as a thermal insulation material, and cannot be used as a wall material alone. In the paper "Thermal Performance of Phase Change Heat Storage Foam Concrete" (et al., "Journal of Composite Materials", 2023, No. 4 (07), 4246-4259), decanoic acid-hexadecanol / silica gel is used as a shaped composite phase change material, and cement-based phase change foam concrete is prepared by physical foaming. The influence of shaped composite phase change material on the dry density, compressive strength and thermal properties of foam concrete is explored, and a phase change heat storage foam concrete wall model is established using ABAQUS finite element software. The research uses expensive phase change materials, and only one type of phase change material with a certain phase change temperature is used. The prepared phase change foam concrete is A07 grade, with a strength less than 4MPa, which cannot meet the requirements of the industry for the mechanical properties of wall materials. In the master's thesis "Preparation and Thermal Properties of New Phase Change Heat Storage Foam Concrete" (Qu Yue, Guangzhou University, February 2021), paraffin is adsorbed by silica gel to form a paraffin / silica gel composite phase change material using the melting adsorption method, and cement-based foam concrete is prepared using it. The influence of the phase change material on the performance of the foam concrete is studied.

[0005] In summary, most of the existing research results and papers use single phase change temperature phase change materials or pure external heat and internal cooling dual phase change temperature principles, and the phase change microcapsules or phase change carriers used are expensive. There is almost no research on the use of brick slag to prepare phase change microcapsules, and there is no related technology and method of using two types of paraffin with different phase change temperatures to prepare phase change microcapsules and matrix heating vacuum adsorption to prepare phase change foam concrete. Therefore, with the continuous deepening of solid waste resource utilization and building energy saving and emission reduction, and the accelerated sustainable development of the construction industry, there is an urgent need to develop a new type of solid waste-based energy-saving wall material that is suitable for all four seasons to solve the technical problems of efficient and high-value-added disposal of solid waste and improvement of building envelope energy saving technology. SUMMARY

[0006] To solve the above problems, that is, to solve the problems raised in the above background art, the present application provides a solid waste-based phase change foam concrete and its preparation method and application, which comprises the following components in the following proportions by weight: 30-37 parts of 42.5-grade ordinary portland cement, 8-12 parts of slag powder, 8-13 parts of brick slag, 1.0-1.5 parts of basalt fiber, 2-3 parts of paraffin with a phase change temperature of 28℃, 2-4 parts of paraffin with a phase change temperature of 18℃, 0.01-0.02 parts of fatty alcohol polyoxyethylene ether, 0.0025-0.005 parts of water-soluble polyvinyl alcohol, 2.5-3.5 parts of hydrogen peroxide, 0.3-0.5 parts of manganese dioxide, 20-27 parts of water, 5-8 parts of gypsum, 1.0-1.5 parts of superabsorbent resin, and 0.1-0.3 parts of surfactant.

[0007] Further provided in the present application is that the slag powder is of S95 grade, and the brick slag is red brick waste slag of MU5-MU15 grade, with a particle size range of 3-5mm.

[0008] Further provided in the present application is that the basalt fiber has a length range of 6-9mm.

[0009] Further provided in the present application is that the gypsum is a grade II or above flue gas desulfurization gypsum as specified in GB / T37785-2019.

[0010] Further provided in the present application is that the surfactant is one of stearic acid monoglyceride or polyoxyethylene fatty alcohol ether.

[0011] Further provided in the present application is that the method comprises the following steps:

[0012] S1, mix the paraffin with a phase change temperature of 18℃, the fatty alcohol polyoxyethylene ether, the water-soluble polyvinyl alcohol, and the water according to a ratio of 74:0.4:0.1:25.5, heat to 90℃, and stir at a constant temperature of 3000rpm / min for 10 minutes, then cool to 50℃ using an external cooling water bath, stir at a constant temperature for 5 minutes, and then continuously stir until cooled to 30℃, to prepare a composite paraffin microemulsion for standby;

[0013] S2, after adding the brick slag to the composite paraffin microemulsion, place it in a vacuum tank with a vacuum degree of >-0.1MPa for vacuum adsorption for 10 minutes, take it out, and crush it using a disc crusher or a hammer crusher, and pass it through an 80-mesh square hole sieve, to prepare phase change brick slag microcapsules for standby;

[0014] S3, add 3-5 parts of water to the superabsorbent resin, to prepare a pre-water-absorbing superabsorbent resin for standby;

[0015] S4, the phase change brick slag microcapsule, pre-water absorption superabsorbent resin, 42.5 grade ordinary portland cement, slag powder, basalt fiber and manganese dioxide are mixed uniformly, then 10-14 parts of water are added and mixed to prepare a slurry for standby;

[0016] S5, hydrogen peroxide is added into the slurry and stirred uniformly, then poured into a mold for solidification, and cured for 28 days to prepare a foam concrete matrix I for standby;

[0017] S6, paraffin with a phase change temperature of 28℃ is laid on the bottom surface of a tray, then one side of the foam concrete matrix I is placed on the paraffin, and the tray is placed in a vacuum drying machine for heating and vacuum adsorption for 25 minutes, and then naturally cooled to room temperature to prepare a foam concrete matrix II for standby;

[0018] S7, gypsum is heated and dehydrated to prepare dehydrated gypsum mainly composed of beta-type hemihydrate gypsum for standby;

[0019] S8, the remaining parts of water and surfactant are added into the dehydrated gypsum to prepare a gypsum slurry for standby;

[0020] S9, the gypsum slurry is coated on the paraffin adsorption surface of the foam concrete matrix II for packaging to prepare a solid waste-based phase change foam concrete with a compressive strength range of 15-22MPa.

[0021] Further provided in the application is that in step S5, the stirring speed ranges from 250-300rpm / min, the stirring time ranges from 10-15 seconds, the curing temperature ranges from 20±2℃, and the relative humidity ranges from >90%.

[0022] Further provided in the application is that in step S6, the temperature in the vacuum drying machine ranges from 35±2℃, the vacuum degree is >-0.1MPa, and the natural cooling is to room temperature or <20℃.

[0023] Further provided in the application is that in step S7, the heating temperature of the gypsum ranges from 100-107℃, and the heating time ranges from 25-35 minutes.

[0024] Further provided in the application is that the application range of the solid waste-based phase change foam concrete includes but is not limited to building blocks, building partition wall plates, preparation of wall bricks and wall materials.

[0025] The beneficial technical effects of the application are:

[0026] 1、The application adopts paraffin wax with phase change temperature 18℃, fatty alcohol polyoxyethylene ether, water-soluble polyvinyl alcohol and water to prepare a composite paraffin wax microemulsion, and adopts brick slag as an adsorption carrier, so that the brick slag particles with a particle size of 3-5mm are adsorbed with paraffin wax through vacuum adsorption, and then are broken into powder to prepare phase change microcapsules. The microcapsule particle population forms a self-encapsulated pore adsorption paraffin wax system, and the particle surface adsorbs paraffin wax and free paraffin wax. Even if the temperature changes during production, part of the paraffin wax will be liquefied, and no flow will be generated. The brick slag phase change microcapsules will be used to prepare foam concrete, and even if part of the paraffin wax is liquefied and separated out in actual engineering, there is enough closed space in the foam concrete for the paraffin wax to migrate, so that the foam concrete matrix does not need to be encapsulated. Compared with existing phase change microcapsules, the application has obvious advantages in terms of technical cost. Moreover, the application provides a high-value recycling technology for waste brick slag, and has obvious economic, environmental and social benefits.

[0027] 2、The application adopts paraffin wax with phase change temperatures of 18℃ and 28℃ to set double phase change intervals, wherein the paraffin wax with a phase change temperature of 18℃ is selected for the minimum indoor heating temperature in winter in severe cold regions, so that the heat storage and energy saving of buildings during the winter heating period can be effectively realized. Moreover, the paraffin wax has a low phase change temperature and a high tendency to melt and flow, so that the paraffin wax is prepared into phase change microcapsules and is designed to exist in a macro-homogeneous state in the foam concrete structure. The paraffin wax with a phase change temperature of 28℃ is selected to ensure the upper limit temperature of 28℃ of the indoor comfort in hot summer conditions, so that the energy saving requirement of buildings during the high-temperature period in summer can be met. The paraffin wax is designed to exist in the form of a phase change energy storage layer near the outdoor side of the foam concrete structure. Thus, the solid waste-based phase change foam concrete of the application can meet the building energy saving requirements in high-temperature and low-temperature environments, and improve the annual effective period of its technical functions.

[0028] 3、The application selects a superabsorbent resin to construct an intelligent opening mode of the adsorption channel of the foam concrete matrix. The superabsorbent resin expands in volume after pre-water absorption and is relatively stable, is embedded in the pore wall of the foam concrete, and ensures the compactness of the pore wall during the hardening and structure forming process of the superabsorbent resin. Moreover, the superabsorbent resin gradually releases water with the decrease of the humidity of the internal environment of the foam concrete during the curing period, and promotes the deep hydration of the cementitious material. After the pore wall of the foam concrete forms sufficient strength, the superabsorbent resin shrinks in volume due to water loss, forms cracks on the pore wall, and makes the original closed pore structure become connected, thereby increasing the adsorption capacity of paraffin wax and improving the penetration depth of liquid paraffin wax to the foam concrete matrix. This technical measure ensures the rapid formation of the structural strength of the foam concrete in the early stage, avoids common engineering problems such as foam collapse, and improves the adsorption capacity of the matrix in the phase change material adsorption process, thereby having obvious technical benefits. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A solid waste-based phase change foam concrete product structure schematic diagram is shown. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art will understand that the embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0031] The present application provides a solid waste-based phase change foam concrete and its preparation method and application. Two kinds of paraffin with phase change temperatures of 18℃ and 28℃ are selected, which are respectively suitable for high temperature in summer and severe cold environment in winter. The indoor environment temperature in summer should be below 28℃, while the standard temperature for winter heating in northern areas is 18℃. The selection of paraffin with these two phase change temperatures can meet the building energy saving needs in summer and winter.

[0032] The brick slag with a particle size of 3-5mm is selected as the adsorption carrier of the composite paraffin microemulsion. A large number of micropores and mesopores are generated in the process of crushing and preparation. The adsorption rate of the composite paraffin microemulsion in the micropores and mesopores of the brick slag is improved through vacuum adsorption, and the adsorption amount in the macropores is reduced. In the process of vacuum adsorption, the liquid phase paraffin adsorbed by the micropores of the brick slag re-solidifies and remains in the brick slag as the temperature decreases.

[0033] The selection of disc crusher or hammer crusher helps to improve the crushing efficiency and shorten the powdering time, thereby avoiding the intensification of paraffin liquefaction and precipitation due to the long heating time of brick slag particles during the crushing process. Since the composite paraffin microemulsion exists in the form of micropore and mesopore adsorption in the brick slag particles, mechanical crushing mainly refines the particles along the macroscopic pores and does not cause the separation of paraffin and brick slag particles during the crushing process. At the same time, the heat energy converted from the mechanical energy is used to make the water in the microemulsion migrate to the outside of the particles. On the one hand, this process can absorb heat and reduce the temperature of the particles, thereby reducing the softening tendency of paraffin. On the other hand, the diffusion speed of water-soluble polyvinyl alcohol is significantly higher than that of paraffin, so it diffuses to the outside of the pores first and solidifies faster during the heating process, thereby blocking the pore channels and forming a self-encapsulation structure of paraffin in the brick slag particles.

[0034] The brick slag particles after adsorbing paraffin are crushed through an 80-mesh square hole screen to obtain phase change brick slag microcapsules, which are used as the internal energy storage unit of the solid waste-based phase change foam concrete. The brick slag microcapsules are uniformly distributed in the solid waste-based phase change foam concrete. In the winter heating period, the phase change of the microcapsules occurs at the critical temperature of 18℃ to store heat, so as to re-solidify and release phase change energy when the indoor environment temperature decreases, thereby maintaining the indoor thermal environment.

[0035] The phase change temperature 28℃ paraffin is selected, and a phase change energy storage layer is formed by single-sided adsorption of solid waste-based phase change foam concrete by a vacuum drying machine. The temperature should not be too high, otherwise it will affect the composition and mechanical properties of the foam concrete matrix. Under vacuum heating conditions, the 28℃ paraffin melts into a liquid phase and penetrates into the surface layer and internal pores of the foam concrete. During the high temperature period, 28℃ is the indoor comfortable critical temperature, when the wall temperature rises to the critical temperature due to factors such as sunlight, the paraffin undergoes phase change and stores heat, thereby reducing the heat transfer efficiency from the external environment to the indoor environment. When the solid waste-based phase change foam concrete is used in building structures, the phase change temperature 28℃ paraffin adsorption surface faces the outdoor environment. When the ambient temperature decreases at night, the phase change energy released by the solidification of the paraffin is preferentially transferred to the outdoor environment.

[0036] The pores in the foam concrete are originally mostly closed pores. The technical purpose of selecting high water absorption resin is to use its water storage and expansion properties. The high water absorption resin, after pre-water absorption and volume expansion, is embedded in the pore wall during the solidification and molding process of the solid waste-based phase change foam concrete. During the curing period of the foam concrete, the water in the high water absorption resin is continuously released, providing cement and other cementitious materials for continuous hydration reaction, which is beneficial to the strength improvement of the foam concrete. With the increase of curing time, the high water absorption resin gradually loses water and shrinks in volume, causing micro cracks in the pore wall, forming channels between the originally closed pores. At this time, since a considerable amount of hydration products has been generated, the foam concrete has a considerable structural strength, so the cracks caused by the loss of water in the high water absorption resin have little effect on the structural strength. During the vacuum heating stage, the water loss rate of the high water absorption resin increases, and the pore wall cracks further expand, which improves the efficiency of liquid paraffin penetrating into the interior of the foam concrete under vacuum conditions.

[0037] Gypsum slurry is selected to coat and seal the phase change temperature 28℃ paraffin adsorption surface. Gypsum hardens quickly, which can improve production efficiency, and its volume slightly expands during hardening, which can prevent the encapsulation layer from shrinking and cracking, ensuring the encapsulation effect of paraffin. When the paraffin is heated and melted, the pores in the foam concrete also provide a migration space for the liquid paraffin, without flowing out to the outside.

[0038] Flue gas desulfurization gypsum, which is also an industrial solid waste material, is selected. Its main component is calcium sulfate dihydrate, which does not have cementitious properties. By heating and dehydrating, it is converted into dehydrated gypsum with β-type hemihydrate gypsum as the main component, which will regain its cementitious properties. The coating and sealing of the foam concrete surface layer by gypsum significantly reduces the difficulty and complexity of the construction connection between the foam concrete and the external decoration process due to the porosity of the surface.

[0039] Stearic acid monoglyceride or polyoxyethylene fatty alcohol ether is selected as a surfactant. On the one hand, the hydrophobicity of the gypsum hardened body can be improved, and the durability of the gypsum hardened body under the condition of potential water erosion can be ensured; on the other hand, the adhesion effect of the gypsum slurry and the foamed concrete under the condition that the foamed concrete surface exists paraffin can be improved.

[0040] The composite paraffin microemulsion prepared by the method S1 can effectively realize the miniaturization of paraffin droplets, and improve the adsorption rate and uniformity of paraffin in micropores and mesopores.

[0041] The disc crusher or the hammer crusher is used for crushing, the heat energy converted from mechanical energy during crushing is utilized, the water-soluble polyvinyl alcohol is rapidly solidified at the outer end of the pores of the brick slag by virtue of the different diffusion rates of the water-soluble polyvinyl alcohol solution and the softened paraffin, and the self-encapsulation of paraffin in the brick slag is completed.

[0042] Embodiment 1

[0043] The solid waste-based phase change foamed concrete provided in the embodiment comprises the following components in parts by weight: 37.0 parts of 42.5-grade ordinary portland cement, 8.0 parts of slag powder, 9.976 parts of brick slag, 1.0 part of basalt fiber, 3.0 parts of paraffin with a phase change temperature of 28℃, 4.0 parts of paraffin with a phase change temperature of 18℃, 0.02 parts of fatty alcohol polyoxyethylene ether, 0.004 parts of water-soluble polyvinyl alcohol, 2.5 parts of hydrogen peroxide, 0.3 parts of manganese dioxide, 25.0 parts of water, 8.0 parts of gypsum, 1.0 part of superabsorbent resin, and 0.2 parts of surfactant.

[0044] The solid waste-based phase change foamed concrete provided in the embodiment is prepared by the following method:

[0045] S1, the paraffin with a phase change temperature of 18℃, the fatty alcohol polyoxyethylene ether, the water-soluble polyvinyl alcohol, and the water are mixed in a ratio of 74:0.4:0.1:25.5, heated to 90℃, and stirred at a speed of 3000 rpm / min for 10 minutes, then cooled to 50℃ by an external cooling water bath and stirred for 5 minutes, and then continuously stirred until cooled to 30℃, to prepare a composite paraffin microemulsion for standby use;

[0046] S2, after the brick slag is added to the composite paraffin microemulsion, the mixture is placed in a vacuum tank with a vacuum degree of greater than-0.1 MPa for vacuum adsorption for 10 minutes, then taken out and crushed by a disc crusher or a hammer crusher, the heat energy converted from mechanical energy during crushing is utilized, the water-soluble polyvinyl alcohol is rapidly solidified at the outer end of the pores of the brick slag by virtue of the different diffusion rates of the water-soluble polyvinyl alcohol solution and the softened paraffin, the self-encapsulation of paraffin in the brick slag is completed, and the phase change brick slag microcapsules are prepared by passing through an 80-mesh square hole screen for standby use;

[0047] S3, 3 parts of water are added to the superabsorbent resin to prepare a pre-water absorption superabsorbent resin for standby;

[0048] S4, the phase change brick slag microcapsule, the pre-water absorption superabsorbent resin, the 42.5 grade ordinary portland cement, the slag powder, the basalt fiber and the manganese dioxide are uniformly mixed, then 12 parts of water is added and stirred to prepare a slurry for standby;

[0049] S5, the hydrogen peroxide is added to the slurry and stirred uniformly, then the stirring is carried out at a speed of 250 rpm / min for 15 seconds until uniform, then the slurry is poured into a mold for solidification, and the solidified product is cured in an environment with a temperature of 20±2℃ and a relative humidity of 90% or above for 28 days to prepare a foam concrete matrix I for standby;

[0050] S6, the paraffin with a phase change temperature of 28℃ is laid on the bottom surface of a tray, then one side of the foam concrete matrix I is placed on the paraffin, the tray is placed in a vacuum drying machine, and heating and vacuum adsorption are carried out at a temperature of 35±2℃ and a vacuum degree of -0.1 MPa for 25 minutes, then the tray is transferred into an environment with a temperature of 20℃ for natural cooling to room temperature to prepare a foam concrete matrix II for standby;

[0051] S7, the gypsum is heated at 107℃ for 35 minutes to prepare dehydrated gypsum mainly composed of β-type hemihydrate gypsum for standby;

[0052] S8, the remaining parts of water and the surfactant are added to the dehydrated gypsum to prepare a gypsum slurry for standby;

[0053] S9, the gypsum slurry is coated on the paraffin adsorption surface of the foam concrete matrix II for packaging to prepare a solid waste-based phase change foam concrete with a compressive strength of 15-22 MPa.

[0054] Example 2

[0055] The solid waste-based phase change foam concrete provided in this example comprises the following components in parts by weight: 30.0 parts of 42.5 grade ordinary portland cement, 12.0 parts of slag powder, 13.0 parts of brick slag, 1.0 part of basalt fiber, 3.0 parts of paraffin with a phase change temperature of 28℃, 2.982 parts of paraffin with a phase change temperature of 18℃, 0.015 parts of fatty alcohol polyoxyethylene ether, 0.003 parts of water-soluble polyvinyl alcohol, 3.5 parts of hydrogen peroxide, 0.3 parts of manganese dioxide, 25.0 parts of water, 8.0 parts of gypsum, 1.0 parts of superabsorbent resin and 0.2 parts of surfactant.

[0056] The solid waste-based phase change foam concrete provided in this example, and the difference between the preparation method and example 1 is that 13 parts of water is added in step S4, the stirring speed is 280 rpm / min in step S5, the stirring time is 12 seconds, the gypsum heating temperature is 102℃ in step S7, and the heating time is 33 minutes.

[0057] Example 3

[0058] The solid waste-based phase change foam concrete provided in this example comprises the following components by weight fraction: 34.0 parts of 42.5-grade ordinary portland cement, 10.0 parts of slag powder, 11.0 parts of brick slag, 1.5 parts of basalt fiber, 2.0 parts of paraffin wax with a phase change temperature of 28℃, 2.9875 parts of paraffin wax with a phase change temperature of 18℃, 0.01 parts of fatty alcohol polyoxyethylene ether, 0.0025 parts of water-soluble polyvinyl alcohol, 2.5 parts of hydrogen peroxide, 0.4 parts of manganese dioxide, 27.0 parts of water, 7.0 parts of gypsum, 1.5 parts of superabsorbent resin, and 0.1 parts of surfactant.

[0059] The solid waste-based phase change foam concrete provided in this example has the same components and weight fractions as in Example 1, except that in step S4, 14 parts of water are added, in step S5, the stirring speed is 300 rpm / min and the stirring time is 10 seconds, and in step S7, the gypsum is heated to a temperature of 100℃ for 35 minutes.

[0060] Example 4

[0061] The solid waste-based phase change foam concrete provided in this example has the same components and weight fractions as in Example 1, except that in step S3, 4 parts of water are added, and in step S4, 11 parts of water are added.

[0062] Example 5

[0063] The solid waste-based phase change foam concrete provided in this example has the same components and weight fractions as in Example 1, except that in step S3, 5 parts of water are added, and in step S4, 10 parts of water are added.

[0064] Comparative Example 1

[0065] The solid waste-based phase change foam concrete provided in this comparative example has the same preparation method as in Example 1, except that the slag powder used in the raw material components is replaced with fly ash, grade II, purchased from Shenyang Huanggu Fly Ash Building Material Co., Ltd., and the other raw material components and weights remain unchanged.

[0066] Comparative Example 2

[0067] The solid waste-based phase change foam concrete provided in this comparative example has the same preparation method as in Example 1, except that the high water absorption resin is not included in the raw materials, the water usage is increased by 1 part, and the other raw material components and weights remain unchanged.

[0068] Comparative Example 3

[0069] The solid waste-based phase change foam concrete provided by the present comparative example has the same preparation method as that of Example 1, except that the paraffin with a phase change temperature of 18°C is replaced by paraffin with a phase change temperature of 28°C in the raw materials used, and the other raw material components and weights remain unchanged.

[0070] Comparative Example 4

[0071] The solid waste-based phase change foam concrete provided by the present comparative example has the same preparation method as that of Example 1, except that the paraffin with a phase change temperature of 28°C is replaced by paraffin with a phase change temperature of 18°C in the raw materials used, and the other raw material components and weights remain unchanged.

[0072] Application Example

[0073] Performance evaluation of the solid waste-based phase change foam concrete of the above examples and comparative examples:

[0074] The solid waste-based phase change foam concrete of Examples 1-5 and Comparative Examples 1-4 was tested for dry density, thermal conductivity, compressive strength, water absorption, heat transfer coefficient, and frost resistance:

[0075] 1. The dry density, compressive strength, and water absorption of the solid waste-based phase change foam concrete were determined in accordance with the requirements of JG / T 266-2011 Foam Concrete.

[0076] 2. The thermal conductivity of the solid waste-based phase change foam concrete was tested in accordance with the requirements of GB / T 10294-2008 Thermal Insulation Materials Steady-state Thermal Resistance and Related Properties Determination Guarded Hot Plate Method.

[0077] 3. The heat transfer coefficient of the solid waste-based phase change foam concrete was tested in accordance with the requirements of GB / T 13475-2008 Thermal Insulation Steady-state Heat Transfer Properties Determination Calibration and Guarded Hot Box Method.

[0078] 4. The frost resistance of the solid waste-based phase change foam concrete was tested in accordance with the requirements of GB 50574 Wall Materials Application Unified Technical Specification.

[0079] The dry density, thermal conductivity, compressive strength, water absorption, heat transfer coefficient, and frost resistance test results of the solid waste-based phase change foam concrete are shown in Table 1 below:

[0080] Table 1 Test Results of Each Group

[0081]

[0082] In combination with the test results of the above table, it can be seen from Comparative Examples 1-3 that when the amounts of 42.5-grade ordinary portland cement, slag powder and brick slag are changed, the dry density, thermal conductivity, compressive strength, water absorption, heat transfer coefficient and frost resistance of the solid waste-based phase change foam concrete are obviously affected. It can be seen from Comparative Examples 1, 4 and 5 that changing the pre-water absorption amount of the superabsorbent resin and the water addition amount of the slurry before foaming will affect the dry density, compressive strength, water absorption and heat transfer coefficient.

[0083] It can be determined from Comparative Example 1 and Comparative Examples 1-4 that using fly ash to replace slag powder will have a significant adverse effect on the compressive strength, heat transfer coefficient and frost resistance of the solid waste-based phase change foam concrete. Not using superabsorbent resin will also significantly affect the dry density, thermal conductivity, compressive strength, water absorption, heat transfer coefficient and frost resistance of the solid waste-based phase change foam concrete. Using only one kind of paraffin wax with a phase change temperature of 28°C or a phase change temperature of 18°C will cause the heat transfer coefficient of the solid waste-based phase change foam concrete to increase.

[0084] This shows that slag powder, superabsorbent resin and two kinds of paraffin wax with a phase change temperature of 28°C and a phase change temperature of 18°C cannot be replaced in the raw materials of the solid waste-based phase change foam concrete of the present application. The slag powder improves the early pore wall strength and the stability of the pore structure of the solid waste-based phase change foam concrete, thereby having a positive effect on the compressive strength, heat transfer coefficient and frost resistance. The water absorption of the superabsorbent resin can change the slurry consistency and adjust the foaming rate and volume. After the pre-water absorption volume expands, the superabsorbent resin is embedded in the pore wall, and the water in it is continuously released during the curing period of the foam concrete, providing continuous hydration reaction for the cementitious materials, which is beneficial to the strength improvement of the foam concrete. As the superabsorbent resin gradually and slowly loses water and shrinks in volume, micro cracks are generated in the pore wall, forming channels between the originally closed pores. During the vacuum heating stage, the water loss rate of the superabsorbent resin increases, and the pore wall cracks further expand, which improves the efficiency of the liquid phase paraffin wax penetrating into the foam concrete under vacuum conditions, thereby improving the dry density, compressive strength, water absorption and heat transfer coefficient of the solid waste-based phase change foam concrete.

[0085] In the examples and comparative examples, the types and parameters of the raw materials used are as follows:

[0086] 42.5-grade ordinary portland cement: 28d compressive strength of 44.1 MPa, purchased from Liaoning Mountain and Water Cement Co., Ltd.;

[0087] Brick slag: building waste bricks generated from the old house demolition site in Shenyang, Liaoning Province, crushed and sieved, purchased from Shenyang Zhongcheng Urban Mineral Resources Development Group Co., Ltd.;

[0088] Basalt fiber: length of 6-9 mm, purchased from Haining Anjie Composite Material Co., Ltd.;

[0089] Slag powder: S95 grade, purchased from Shenyang Jinshi Shield Slag Powder Co., Ltd.

[0090] Paraffin wax: phase transition temperature is 18℃ and 28℃, both purchased from Donglin High Polymer Material Co., Ltd.

[0091] Fatty alcohol polyoxyethylene ether: chemical reagent, analytical pure, purchased from Shenyang Jin Gua Laboratory Equipment Business;

[0092] Water-soluble polyvinyl alcohol: purchased from Shanghai Kaeyuan Chemical Industry;

[0093] Hydrogen peroxide: mass concentration 30%, purchased from Shenyang Jin Gua Laboratory Equipment Business;

[0094] Manganese dioxide: chemical reagent, analytical pure, purchased from Shenyang Jin Gua Laboratory Equipment Business;

[0095] Gypsum: secondary flue gas desulfurization gypsum, purchased from Shenyang Runfeng Desulfurization Gypsum Comprehensive Utilization Co., Ltd.

[0096] Superabsorbent resin: content ≥99%, purchased from Funaxin Material Technology (Shanghai) Co., Ltd.

[0097] Surfactant: stearic acid monoglyceride, chemical reagent, analytical pure, purchased from Shenyang Jin Gua Laboratory Equipment Business.

[0098] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the present application, and equivalent substitutions can be made to parts thereof, and in particular, each of the technical features mentioned in each of the embodiments can be combined in any manner, provided that there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0099] In the description of the present application, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicating the direction or positional relationship are based on the direction or positional relationship shown in the drawings, which is merely for the convenience of description, and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0100] In addition, it needs to be explained that in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0101] The term "comprising" or any other similar word is intended to encompass a non-exclusive inclusion, so that a process, article, or apparatus / device including a series of elements includes not only those elements, but also other elements not explicitly listed, or inherent to such process, article, or apparatus / device.

[0102] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will fall within the protection scope of the present application.

Claims

1. A solid waste-based phase change foam concrete, characterized in that: The solid waste-based phase change foam concrete comprises the following components in the following proportions by weight: 30-37 parts of 42.5-grade ordinary portland cement, 8-12 parts of slag powder, 8-13 parts of brick slag, 1.0-1.5 parts of basalt fiber, 2-3 parts of paraffin wax with a phase change temperature of 28℃, 2-4 parts of paraffin wax with a phase change temperature of 18℃, 0.01-0.02 parts of fatty alcohol polyoxyethylene ether, 0.0025-0.005 parts of water-soluble polyvinyl alcohol, 2.5-3.5 parts of hydrogen peroxide, 0.3-0.5 parts of manganese dioxide, 20-27 parts of water, 5-8 parts of gypsum, 1.0-1.5 parts of superabsorbent resin, and 0.1-0.3 parts of surfactant; The preparation method comprises the following steps: S1, mix the paraffin wax with a phase change temperature of 18℃, the fatty alcohol polyoxyethylene ether, the water-soluble polyvinyl alcohol, and the water according to a ratio of 74:0.4:0.1:25.5, heat to 90℃, and stir at a speed of 3000rpm / min for 10 minutes, then cool to 50℃ using an external cooling water bath, stir for 5 minutes, and then continuously stir until cooled to 30℃, to obtain a composite paraffin wax microemulsion for standby; S2, after adding the brick slag into the composite paraffin wax microemulsion, place it in a vacuum tank with a vacuum degree of greater than-0.1MPa for vacuum adsorption for 10 minutes, take it out, crush it using a disc crusher or a hammer crusher, and pass it through an 80-mesh square hole sieve to obtain phase change brick slag microcapsules for standby; S3, add 3-5 parts of water into the superabsorbent resin to obtain pre-water-absorbed superabsorbent resin for standby; S4, mix the phase change brick slag microcapsules, the pre-water-absorbed superabsorbent resin, the 42.5-grade ordinary portland cement, the slag powder, the basalt fiber, and the manganese dioxide uniformly, and then add 10-14 parts of water to obtain a slurry for standby; S5, after adding the hydrogen peroxide into the slurry and stirring uniformly, pour the slurry into a mold for solidification, and then maintain it for 28 days for curing to obtain a foam concrete substrate I for standby; S6, place the paraffin wax with a phase change temperature of 28℃ on the bottom surface of a tray, place one side of the foam concrete substrate I on the paraffin wax, and then place the tray into a vacuum drying machine for heating and vacuum adsorption for 25 minutes, and then naturally cool to room temperature to obtain a foam concrete substrate II for standby; S7, heat and dehydrate the gypsum to obtain dehydrated gypsum mainly composed of β-type hemihydrate gypsum for standby; S8, add the remaining parts of water and the surfactant into the dehydrated gypsum to obtain a gypsum slurry for standby; S9, coat the gypsum slurry on the paraffin adsorption surface of the foam concrete substrate II for packaging to obtain a solid waste-based phase change foam concrete with a compressive strength range of 15-22MPa.

2. The solid waste-based phase change foam concrete according to claim 1, characterized in that: The slag powder has a mass grade of S95, and the brick slag is red brick waste residue with a grade of MU5-MU15 and a particle size range of 3-5mm.

3. The solid waste-based phase change foam concrete according to claim 1, characterized in that: The basalt fiber has a length range of 6-9mm.

4. The solid waste-based phase change foam concrete according to claim 1, characterized in that: The gypsum is a second-grade or above flue gas desulfurization gypsum according to GB / T 37785-2019.

5. The solid waste-based phase change foam concrete according to claim 1, characterized in that: The surfactant is one of stearic acid monoglyceride or polyoxyethylene fatty alcohol ether.

6. A method of producing a solid waste based phase change foam concrete according to any one of claims 1-5, characterized by: The preparation method comprises the following steps: S1, mix paraffin wax with phase change temperature of 18℃, fatty alcohol polyoxyethylene ether, water-soluble polyvinyl alcohol, water in the ratio of 74:0.4:0.1:25.5, heat to 90℃, constant temperature stirring at 3000rpm / min for 10 minutes, then cooled to 50℃ with external cooling water bath, constant temperature stirring for 5 minutes, then continue to stir until cooled to 30℃, prepare composite paraffin wax microemulsion for standby; S2, after adding brick slag into the composite paraffin wax microemulsion, put it into a vacuum tank with vacuum degree of-0.1MPa for vacuum adsorption for 10min, take it out, crush it with disc crusher or hammer crusher, and pass through 80 mesh square hole screen, prepare phase change brick slag microcapsule for standby; S3, add 3-5 parts of water into superabsorbent resin, prepare pre-water absorption superabsorbent resin for standby; S4, mix phase change brick slag microcapsule, pre-water absorption superabsorbent resin, 42.5 grade ordinary portland cement, slag powder, basalt fiber and manganese dioxide uniformly, add 10-14 parts of water to mix, prepare slurry for standby; S5, after adding hydrogen peroxide into the slurry and stirring uniformly, pour it into the mold to solidify, and maintain for 28d, prepare foam concrete matrix I for standby; S6, lay paraffin wax with phase change temperature of 28℃ on the bottom surface of the tray, place one side of the foam concrete matrix I on it, put the tray into the vacuum drying machine for heating and vacuum adsorption for 25min, and naturally cool to room temperature to prepare foam concrete matrix II for standby; S7, heat the gypsum to dehydrate to prepare dehydrated gypsum with β-type hemihydrate gypsum as the main component for standby; S8, add the remaining parts of water and surfactant into the dehydrated gypsum to prepare gypsum slurry for standby; S9, coat the gypsum slurry on the paraffin adsorption surface of the foam concrete matrix II for packaging, prepare solid waste-based phase change foam concrete with compressive strength range of 15-22MPa.

7. A method of making a solid waste based phase change foam concrete according to claim 6, characterised in that: In the step S5, the stirring speed range is 250-300rpm / min, the stirring time range is 10-15 seconds, the curing temperature range is 20±2℃, and the relative humidity range is >90%.

8. A method of making a solid waste based phase change foam concrete according to claim 7, characterised in that: In the step S6, the temperature range in the vacuum drying machine is 35±2℃, the vacuum degree is >-0.1MPa, and the natural cooling is to room temperature or <20℃.

9. A method of making a solid waste based phase change foam concrete according to claim 8, characterised in that: In the step S7, the gypsum heating temperature range is 100-107℃, and the heating time range is 25-35min.

10. Use of the solid waste based phase change foamed concrete as claimed in claim 1, wherein: The application range of the solid waste-based phase change foam concrete includes but is not limited to building blocks and building partition wall boards.

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