Preparation method of heat reflection building material

Abstract

The invention provides a preparation method of a heat reflection building material, and belongs to the field of building materials. Sodium hydroxide, sodium silicate and water are mixed to prepare an alkali activator solution, and the modulus of the alkali activator solution is 1.3; mixing the alkali-activated solution with a dispersing agent, a surfactant and a heat reflection functional material to obtain a mixed solution; mixing the active sandstone with a mineral admixture to obtain a cementing material; the mixed solution and the cementing material are fully stirred and mixed, then standard sand is added, mixing and vibrating are conducted again, the mixture is put into a mold to be formed, curing is conducted under the standard curing condition, the heat reflection building material is obtained, and the heat reflection building material has the remarkable advantages that raw materials are green and low-carbon, the heat reflection performance is excellent, and structure-function integration is achieved.

Description

Technical Field

[0001] The invention belongs to the field of building materials, and particularly relates to a method for preparing a heat-reflective building material. Background Art

[0002] Due to factors such as the impermeability of concrete buildings, asphalt, and cement pavements, their low thermal reflectivity (0.1-0.4), high heat absorption (approximately 0.6), and good thermal conductivity (thermal conductivity greater than 1.2 W / m·K), many cities experience sharp increases in both exterior and interior temperatures during the summer (reaching over 60°C on some pavements, roofs, or exterior walls), creating an "urban heat island effect." This not only impacts the city's environmental quality and public health, but also dramatically increases energy consumption for cooling during extremely hot weather.

[0003] At present, my country's research on the management of urban "heat island effect" is still in its early stages. Traditional methods of managing the urban "heat island effect" include increasing urban greening rates, applying heat-reflective coatings on roofs, and installing insulation layers. For example, patent number CN117210111A, "An anti-corrosion reflective thermal insulation coating and its preparation method," while "heat-reflective coating" can effectively promote the management of the urban "heat island effect," has significant disadvantages such as high cost, weak interfacial contact adhesion, low strength and wear resistance, and susceptibility to aging and damage, resulting in a short service life (heat-reflective coatings use organic materials as a base material, which are more susceptible to aging and damage than inorganic materials).

[0004] Currently, patent number CN115340331A "A method for preparing a heat-reflective cement-based material" discloses a cement-based heat-reflective material. However, traditional cementitious materials (Portland cement) have extremely low heat reflection efficiency and low specific heat capacity, and are not suitable for use as cementitious materials for heat-reflective building materials.

[0005] Therefore, there is an urgent need for a heat-reflecting building material based on a novel cementitious material. Summary of the Invention

[0006] In view of this, the object of the present invention is to provide a method for preparing a heat-reflective building material, which has significant advantages such as green and low-carbon raw materials, excellent heat-reflective performance, and structural-functional integration.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a heat-reflective building material, comprising the following steps:

[0009] S1: Sodium hydroxide, sodium silicate and water are mixed to prepare an alkaline activator solution, wherein the alkaline activator solution has a modulus of 1.3;

[0010] S2: mixing the alkali excitation solution with the surfactant and the heat reflective functional material to obtain a mixed solution;

[0011] S3: mixing the active arsenic sandstone and the mineral admixture to obtain a cementitious material;

[0012] S4: The mixed liquid and the cementitious material are fully stirred and mixed, and then standard sand is added, mixed and vibrated again, and then placed into a mold for shaping, and cured under standard curing conditions to obtain a heat-reflective building material.

[0013] Preferably, the sodium silicate in S1 is sodium water glass with a modulus of 3.26 and a Baume degree of 38.5 degrees; the mass ratio of sodium hydroxide, sodium silicate and water is 1:5.9:10.

[0014] Preferably, the mass ratio of the alkaline excitation solution, the surfactant, and the heat reflective functional material in S2 is 75.5:1:6.7;

[0015] The surfactant is one or more of gum arabic, cetyltrimethylammonium bromide, and sodium lauryl sulfate.

[0016] Preferably, the heat-reflecting functional material in S2 is one or more of rutile TiO2, ZnO, BaO, and hollow glass microspheres, and the refractive index of the heat-reflecting functional material is ≥2.0.

[0017] Preferably, the mass ratio of the mineral admixture to the active arsenic sandstone in S3 is 1:0.5-2.

[0018] Preferably, the preparation method of the active arsenic sandstone in S3 is:

[0019] Step 1: Place the arsenic sandstone in a drying oven at 110°C and bake for 24 hours;

[0020] Step 2: Place the dried arsenic sandstone into a muffle furnace, calcining it at a temperature of 550-900°C, for 1 hour, at a heating rate of 5°C / min;

[0021] Step 3: Cool the calcined arsenic sandstone to room temperature and place it in a ball mill at a speed of 500 rpm for 5 minutes.

[0022] The components of the arsenic sandstone are as follows: the main mineral components of the arsenic sandstone are quartz, montmorillonite, potassium feldspar and calcite, and the contents thereof are 15wt.% to 70wt.%, 10wt.% to 35wt.%, 5wt.% to 25wt.% and 0wt.% to 26wt.%, respectively.

[0023] Preferably, the mineral admixture in S3 includes one or more of mineral powder and fly ash; the specific surface area of ​​the fly ash and mineral powder is independently not less than 400m 2 / kg.

[0024] Preferably, the mass ratio of the heat-reflecting functional material, the gelling material and the standard sand in the mixed liquid in S4 is 1:10-20:30-60.

[0025] Preferably, the standard sand in S4 complies with the Chinese ISO standard sand;

[0026] Preferably, the standard curing conditions in S4 are a temperature of 20±2° C., a relative humidity ≥95%, and a curing period of not less than 28 days.

[0027] Preferably, the solar reflectance of the heat-reflecting arsenic sandstone-based building material is 45.3% to 72.8%.

[0028] This invention uses modified activated argillaceous sandstone as the primary cementitious material, combined with a high-refractive-index heat-reflecting functional component and surface-functional additives, to achieve a synergistic improvement in optical reflectivity and mechanical properties during the structural forming process. The high crystallinity of quartz and mica in argillaceous sandstone significantly increases thermal reflectivity, and its specific heat capacity is significantly higher than that of ordinary Portland cement. Combined with the microstructure's "mirror effect" and porous thermal insulation, the resulting material possesses excellent heat reflection, thermal insulation, and mechanical stability, overcoming the problems of traditional surface coatings that are prone to shedding and low utilization, making it suitable for green building scenarios with high thermal control requirements, such as exterior walls and roofs.

[0029] Contains at least the following beneficial technical effects:

[0030] 1. By introducing high-refractive index materials such as TiO2 and activated arsenic sandstone, the solar reflectance of the material is effectively improved, reaching a maximum of 72.8%, which is significantly better than traditional cement-based materials and helps alleviate the urban heat island effect.

[0031] 2. Heat-reflective functional materials are added internally to produce arsenic sandstone-based heat-reflective building materials. Compared with traditional heat-reflective coatings, it avoids the problems of easy aging and falling off of the outer coating, and has both excellent mechanical properties and heat-reflective functions.

[0032] 3. The cementitious system is constructed with raw materials such as arsenic sandstone and mineral powder. The materials are non-toxic and harmless, and the preparation process is green, environmentally friendly and pollution-free. It has the characteristics of low carbon emissions and efficient resource utilization, achieving the coordinated goals of low-carbon development of building materials and high value of solid waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is an optical microscope image of some minerals separated from arsenic sandstone. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0035] Unless otherwise defined, technical or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description. It is intended that all variations within the meaning and range of equivalents of the claims be embraced herein, and any reference signs in the claims should not be construed as limiting the claims to which they relate.

[0037] Furthermore, it should be understood that although this specification describes the embodiments, not every embodiment includes only one independent technical solution. This description is for clarity only. Those skilled in the art should consider the specification as a whole. The technical solutions in the various embodiments may also be appropriately combined to form other embodiments that are understandable to those skilled in the art. These other embodiments are also encompassed within the scope of protection of the present invention.

[0038] It should also be understood that the specific embodiments described above are only used to explain the present invention, and the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the scope of protection of the present invention / invention.

[0039] The materials used in the following examples are as follows:

[0040] Sodium silicate is sodium water glass with a modulus of 3.26 and a Baume degree of 38.5 degrees.

[0041] The preparation method of active arsenic sandstone is:

[0042] Step 1: Place the arsenic sandstone in a drying oven at 110°C and bake for 24 hours;

[0043] Step 2: Place the dried arsenic sandstone into a muffle furnace, calcining it at a temperature of 500-900°C for 1 hour at a heating rate of 5°C / min;

[0044] Step 3: Cool the calcined arsenic sandstone to room temperature and place it in a ball mill at a speed of 500 rpm for 5 minutes.

[0045] The components of the arsenic sandstone are as follows: the main mineral components of the arsenic sandstone are quartz, montmorillonite, potassium feldspar and calcite, and the contents thereof are 15wt.% to 70wt.%, 10wt.% to 35wt.%, 5wt.% to 25wt.% and 0wt.% to 26wt.%, respectively.

[0046] The specific surface area of ​​fly ash and mineral powder shall not be less than 400m 2 / kg.

[0047] Example 1

[0048] Preparation of heat-reflective arsenic sandstone-based building materials:

[0049] a. First, 13.37 parts of NaOH, 78.75 parts of sodium silicate, and 135 parts of water were placed in a magnetic stirrer at a speed of 300 r / min and stirred for 3 minutes to obtain an alkaline excitation solution;

[0050] b. Add 22 parts of TiO2 and 3 parts of sodium lauryl sulfate into the alkali-activated solution and mix and stir to obtain a mixed solution;

[0051] c. Put 150 parts of activated arsenic sandstone (calcined at 700°C and kept at this temperature for 1 hour), 300 parts of mineral powder, and 1350 parts of standard sand into a 300 rpm mixer and stir for 5 minutes to obtain a cementitious material;

[0052] d. Stir the mixed liquid with the cementitious material to obtain a heat-reflecting arsenic sandstone-based building material mixture, pour it into a 40 mm × 40 mm × 160 mm mold, remove the mold after 1 day, and perform standard curing for 28 days to obtain the heat-reflecting arsenic sandstone-based building material.

[0053] This example was conducted with reference to GB / T 31389-2015, "Technical Requirements and Evaluation Methods for Heat-Reflective Materials for Building Exterior Walls and Roofs," and JG / T 235-2014, "Architectural Reflective Thermal Insulation Coatings." The prepared heat-reflective sandstone-based building material was tested using an ultraviolet-visible-near-infrared photometer and an integrating sphere. The test wavelength range was 200-2500 nm for sunlight, and the solar reflectance of the heat-reflective sandstone-based building material was calculated. The solar reflectance of the heat-reflective sandstone-based building material in this example was 68.6%.

[0054] Example 2

[0055] Heat-reflecting arsenic sandstone-based building materials were prepared according to the steps of Example 1, except that:

[0056] 22 parts TiO2 to 45 parts TiO2

[0057] 3 parts of sodium lauryl sulfate to 6 parts of sodium lauryl sulfate

[0058] The heat reflective performance of the heat reflective sandstone-based building material prepared in this embodiment was tested using the test method of Example 1. The results showed that the solar reflectance of the heat reflective sandstone-based building material was 65.5%.

[0059] Example 3

[0060] Heat-reflecting arsenic sandstone-based building materials were prepared according to the steps of Example 1, except that:

[0061] 150 active arsenic sandstones are now 225 active arsenic sandstones

[0062] 300 parts of mineral powder sodium is changed to 225 parts of mineral powder

[0063] The heat reflective performance of the heat reflective sandstone-based building material prepared in this embodiment was tested using the test method of Example 1. The results showed that the solar reflectance of the heat reflective sandstone-based building material was 70.8%.

[0064] Example 4

[0065] Heat-reflecting arsenic sandstone-based building materials were prepared according to the steps of Example 1, except that:

[0066] 150 active arsenic sandstones changed to 300 active arsenic sandstones

[0067] 300 parts of mineral powder sodium is changed to 115 parts of mineral powder

[0068] The heat reflective performance of the heat reflective sandstone-based building material prepared in this embodiment was tested using the test method of Example 1. The results showed that the solar reflectance of the heat reflective sandstone-based building material was 72.8%.

[0069] Example 5

[0070] Heat-reflecting arsenic sandstone-based building materials were prepared according to the steps of Example 1, except that:

[0071] Change 150 parts of activated arsenic sandstone (calcined at 700℃ and kept warm for 1 hour) to 150 parts of activated arsenic sandstone (calcined at 550℃ and kept warm for 1 hour)

[0072] The heat reflective performance of the heat reflective sandstone-based building material prepared in this embodiment was tested using the test method of Example 1. The results showed that the solar reflectance of the heat reflective sandstone-based building material was 67.8%.

[0073] Example 6

[0074] Heat-reflecting arsenic sandstone-based building materials were prepared according to the steps of Example 1, except that:

[0075] Change 150 parts of activated arsenic sandstone (calcined at 700℃ and kept warm for 1 hour) to 150 parts of activated arsenic sandstone (calcined at 900℃ and kept warm for 1 hour)

[0076] The heat reflective performance of the heat reflective sandstone-based building material prepared in this embodiment was tested using the test method of Example 1. The results showed that the solar reflectance of the heat reflective sandstone-based building material was 46.7%.

[0077] Comparative Example 1

[0078] Heat-reflecting arsenic sandstone-based building materials were prepared according to the steps of Example 1, except that:

[0079] No TiO2 and sodium lauryl sulfate were added.

[0080] The heat reflective properties of the heat-reflective sandstone-based building material prepared in this embodiment were tested using the test method of Example 1. The results showed that the solar reflectance of the heat-reflective sandstone-based building material itself was 45.3%, far lower than the solar reflectance of the heat-reflective sandstone-based building material added with TiO2 and sodium lauryl sulfate. This shows that modifying sandstone can significantly increase its solar reflectance, demonstrating excellent heat reflective properties.

[0081] Comparative Example 2

[0082] Preparation of cement-based heat-reflective cementitious materials

[0083] 450 parts PO 42.5 Portland cement, 135 parts water.

[0084] The heat reflective performance of the heat reflective sandstone-based building material prepared in this embodiment was tested using the test method of Example 1. The results showed that the solar reflectance of the cement-based material was 16.3%.

[0085] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for preparing a heat-reflective building material, characterized in that: The following steps are involved: S1: Sodium hydroxide, sodium silicate and water are mixed to prepare an alkaline activator solution, wherein the alkaline activator solution has a modulus of 1.3; S2: mixing the alkali excitation solution with the surfactant and the heat reflective functional material to obtain a mixed solution; S3: mixing the active arsenic sandstone and the mineral admixture to obtain a cementitious material; S4: The mixed liquid and the cementitious material are fully stirred and mixed, and then standard sand is added, mixed and vibrated again, and then placed into a mold for shaping, and cured under standard curing conditions to obtain a heat-reflective building material.

2. The preparation method according to claim 1, characterized in that The sodium silicate in S1 is sodium water glass with a modulus of 3.26 and a Baume degree of 38.5 degrees; the mass ratio of sodium hydroxide, sodium silicate and water is 1:5.9:

10.

3. The preparation method according to claim 1, characterized in that The mass ratio of the alkaline excitation solution, the surfactant, and the heat reflective functional material in S2 is 75.5:1:6.7; The surfactant is one or more of gum arabic, cetyltrimethylammonium bromide, and sodium lauryl sulfate.

4. The preparation method according to claim 1, characterized in that The heat-reflecting functional material in S2 is one or more of rutile TiO2, ZnO, BaO, and hollow glass microspheres, and the refractive index of the heat-reflecting functional material is ≥2.

0.

5. The preparation method according to claim 1, characterized in that The mass ratio of the mineral admixture to the active arsenic sandstone in S3 is 1:0.5-2.

6. The preparation method according to claim 5, characterized in that The preparation method of the active arsenic sandstone in S3 is: Step 1: Place the arsenic sandstone in a drying oven at 110°C and bake for 24 hours; Step 2: Place the dried arsenic sandstone into a muffle furnace, calcining it at a temperature of 550-900°C, for 1 hour, at a heating rate of 5°C / min; Step 3: Cool the calcined arsenic sandstone to room temperature and place it in a ball mill at a speed of 500 rpm for 5 minutes. The components of the arsenic sandstone are as follows: the main mineral components of the arsenic sandstone are quartz, montmorillonite, potassium feldspar and calcite, and the contents thereof are 15wt.% to 70wt.%, 10wt.% to 35wt.%, 5wt.% to 25wt.% and 0wt.% to 26wt.%, respectively.

7. The preparation method according to claim 5, characterized in that The mineral admixture in S3 includes one or more of mineral powder and fly ash; the specific surface area of ​​the fly ash and mineral powder is independently not less than 400m 2 / kg.

8. The preparation method according to claim 1, characterized in that The mass ratio of the heat-reflecting functional material, the gelling material and the standard sand in the mixed liquid in S4 is 1:10-20:30-60.

9. The preparation method according to claim 1, characterized in that The standard curing conditions in S4 are a temperature of 20±2° C., a relative humidity of ≥95%, and a curing period of not less than 28 days.

10. The preparation method according to claim 1, characterized in that The solar reflectance of the heat-reflecting arsenic sandstone-based building material is 45.3% to 72.8%.

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