Construction waste thermal insulation mortar and preparation method thereof

Abstract

The invention belongs to the technical field of thermal insulation building materials, and particularly relates to construction waste thermal insulation mortar and a preparation method thereof. The construction waste thermal insulation mortar is prepared from the following raw materials: glass beads, cement, sand, sepiolite, water, rubber powder, cellulose, starch ether, a thixotropic agent, an active agent, an air entraining agent, heavy calcium powder, cellulose ether and construction waste fine powder. The thermal insulation mortar prepared by taking the construction waste fine powder as one of the raw materials not only meets the requirements of the thermal insulation mortar on mechanical properties, thermal insulation properties and the like, but also consumes the construction waste fine powder as much as possible, and has good heat storage and heat release capabilities in practical application.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal insulation building materials, and more specifically relates to a construction waste thermal insulation mortar and a preparation method thereof. Background Art

[0002] With the rapid development of the construction industry, while increasing the demand for concrete, more construction waste has been generated invisibly. How to resourcefully utilize construction waste has become one of the future development trends of concrete. Construction waste not only occupies a large amount of land resources but also has a serious impact on the ecological environment. The implementation of construction waste recycling technology has extremely important environmental, economic, and social significance and can promote the circular utilization of resources and sustainable development.

[0003] Under the call of building energy conservation and the sustainable development of the construction industry, extensive research has been carried out on building walls with thermal insulation functions. At present, in building walls with thermal insulation functions, concrete waste in construction waste is generally used as a substitute material to replace substances such as cement, fly ash, and aggregates in raw materials, thereby greatly enhancing the use value of construction waste. However, due to the particularity of concrete waste, large-area substitution of raw materials will have a greater impact on the performance of materials. Therefore, how to reasonably apply construction waste to materials such as thermal insulation mortar without significantly affecting the performance of materials has become the focus of research. Summary of the Invention

[0004] The purpose of the present invention is to provide a construction waste thermal insulation mortar and a preparation method thereof. By reasonably applying construction waste fine powder, the problems existing in the above-mentioned prior art are solved, and it is realized that adding construction waste to the thermal insulation mortar still has a sufficiently low thermal conductivity and excellent mechanical properties.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention: Provide a construction waste thermal insulation mortar, the raw materials of which include: solid components, admixtures, and water;

[0007] By mass, the solid components include: 40 parts of expanded perlite, 50 parts of cement, 8 parts of sand, and 2 parts of sepiolite;

[0008] The mass ratio of the water to the solid components is 0.84:1;

[0009] The addition amount of the admixture is 85‰ - 97.5‰ of the mass of the solid components;

[0010] The admixture includes latex powder, cellulose, starch ether, thixotropic agent, activator, air-entraining agent, heavy calcium powder, cellulose ether and fine powder of construction waste, and the mass ratio is 15:4:1:1.5:11:(0.5 - 3):50:(1 - 6):(1 - 6).

[0011] Further, the cement is PO42.5 Portland cement.

[0012] Further, the bulk density of the vitrified microbeads is 90 - 110 kg / m 3 , and the thermal conductivity is 0.037 W·m -1 ·K -1 , and the particle size is 0.5 - 1.5 mm.

[0013] Further, the sand is standard sand, medium sand, the bulk density is 1.6 g / cm 3 , and the mud content is 1.5%.

[0014] Further, the latex powder is redispersible latex powder and / or ethylene-vinyl acetate copolymer latex powder.

[0015] Further, the activator is silica white carbon black activity enhancer.

[0016] Further, the bulk density of the sepiolite is 1000 - 2200 kg / m 3 , and the specific surface area is 350 kg / m 2 .

[0017] Further, the cellulose ether is hydroxypropyl methyl cellulose ether.

[0018] Further, the air-entraining agent is sodium dodecyl sulfate k12 air-entraining agent.

[0019] Further, the thixotropic agent is NY-12W polyurethane thickening thixotropic agent.

[0020] Further, the fine powder of construction waste is the undersize material after the concrete waste is crushed and passed through a 200-mesh sieve.

[0021] The second technical solution of the present invention: A preparation method of the above-mentioned construction waste thermal insulation mortar, the steps include:

[0022] After dry-mixing and uniformly mixing cement, vitrified microbeads, heavy calcium powder, sand, latex powder, activator, sepiolite, cellulose, starch ether, air-entraining agent, thixotropic agent, cellulose ether and fine powder of construction waste, add water and stir evenly to obtain the construction waste thermal insulation mortar.

[0023] Further, the stirring is carried out at a rotation speed of 130 - 150 rpm for 2 min first, then at a rotation speed of 270 - 300 rpm for 1 min, and finally at a rotation speed of 130 - 150 rpm for 1 min.

[0024] By the preparation method of the present invention, a building waste thermal insulation mortar is prepared, which not only meets various requirements of the thermal insulation mortar but also achieves the purpose of consuming fine building waste powder.

[0025] The third technical solution of the present invention: Provide an application of the above building waste thermal insulation mortar in the construction of energy-saving buildings.

[0026] The present invention discloses the following technical effects:

[0027] The thermal insulation mortar prepared by the present invention using fine building waste powder as one of the raw materials not only meets the requirements of the mechanical properties, thermal insulation performance, etc. of the thermal insulation mortar, but also consumes fine building waste powder as much as possible, and has excellent heat storage and heat release capabilities in practical applications. Description of the Drawings

[0028] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0029] Figure 1 It is a curve of the change in the thermal conductivity with the increase in the addition amount of fine building waste powder.

[0030] Figure 2 It is a curve of the change in the mechanical properties with the increase in the addition amount of fine building waste powder.

[0031] Figure 3 It is an SEM diagram of the samples of Examples 1 - 3, where a is Example 1, b is Example 2, and c is Example 3.

[0032] Figure 4 It is the linear shrinkage rate under different addition amounts of fine building waste powder.

[0033] Figure 5 It is a schematic diagram of the six - side numbering of the test block.

[0034] Figure 6 It is a temperature change curve of the S surface.

[0035] Figure 7 It is a temperature change curve of the X surface.

[0036] Figure 8 It is a comparison diagram of the temperature - decreasing curves at the center of the thermal insulation mortar test blocks of Y and Y3.

[0037] Figure 9 Thermal imaging diagram at the center of the thermal insulation mortar specimens of Y and Y3.

[0038] Figure 10 Temperature change curve of the S surface.

[0039] Figure 11 Temperature change curve of the X surface.

[0040] Figure 12 Comparison diagram of the heating curves at the center of the thermal insulation mortar specimens of Y and Y3.

[0041] Figure 13 Thermal imaging diagram at the center of the thermal insulation mortar specimens of Y and Y3. Detailed implementation manners

[0042] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0043] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0044] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0045] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the present invention specification, which are obvious to those skilled in the art. Other implementation manners obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are only exemplary.

[0046] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0047] Vitrified microspheres are a kind of lightweight, porous, inorganic vitreous mineral material, with excellent heat preservation, heat insulation, fire prevention, and sound absorption properties. As an admixture, it can effectively improve the heat preservation performance, lightweight level, and mechanical properties of thermal insulation mortar, while reducing the self-weight and energy consumption of buildings, and having the advantages of safety, environmental protection, fire prevention, and flame retardancy.

[0048] Sepiolite is a fibrous hydrated magnesium silicate clay mineral, which has excellent physical and chemical properties. As an admixture, sepiolite can significantly improve the bonding strength, waterproof performance, and heat preservation performance of thermal insulation mortar. Specifically, sepiolite can form a dense internal structure by filling the voids in the mortar, enhancing the impermeability and crack resistance of the mortar; at the same time, its good water absorption can resist the erosion of water, thus enhancing the waterproof performance; in addition, the pore structure and low density of sepiolite also help to reduce the thermal conductivity of the mortar and improve the heat preservation effect.

[0049] An air-entraining agent is a special chemical substance that can introduce tiny air bubbles into the mortar. It is mainly composed of basic materials such as cement and lime, surface active substances, and pore-forming agents. The functions of the air-entraining agent are mainly reflected in the following aspects: First, it can improve the plasticity and fluidity of the mortar, making the construction more convenient; second, by introducing air bubbles, it can reduce the dry shrinkage and wet expansion stress of the mortar, improving its durability and crack resistance; third, the air bubbles provide a certain expansion space when freezing, which can enhance the freeze-thaw resistance of the mortar; finally, the air-entraining agent can also reduce the pore connectivity inside the mortar, reducing the penetration of water and harmful substances, thereby improving its impermeability.

[0050] Cellulose ether is a high molecular compound with an ether structure made from cellulose, having good water retention, thickening, and lubricating properties. As an admixture, cellulose ether can form a lubricating film in the mortar, improving the fluidity and slip of the mortar, and preventing cracks from occurring during thick-layer application. At the same time, cellulose ether can also absorb and retain water, extending the working time of the mortar, and ensuring the stability and controllability during the construction process.

[0051] The cement used in the specific implementation of the present invention is PO42.5 Portland cement; the bulk density of the vitrified microspheres used is between 90 - 110 kg / m 3 and the thermal conductivity is 0.037 W·m -1 ·K -1 , and the particle size is between 0.5 - 1.5 mm; the specification parameters of the sand used are standard sand, medium sand, the bulk density is 1.6 g / cm 3 , and the mud content is 1.5%; the bulk density of sepiolite is between 1000 - 2200 kg / m 3 and the specific surface area is 350 kg / m 2 .

[0052] Unless otherwise specified, the "parts" involved in the specific implementation of the present invention refer to "parts by mass", and the "room temperature" and "normal temperature" involved refer to 20-30°C.

[0053] For other components not clearly defined in the specific implementation of the present invention, commonly used components in the art can be used.

[0054] Example 1

[0055] A preparation method of building waste thermal insulation mortar, the steps include:

[0056] S1. Raw material preparation: 560 parts of PO42.5 portland cement, 400 parts of expanded perlite, 52.5 parts of heavy calcium powder, 80 parts of sand, 15.75 parts of redispersible latex powder, 11.55 parts of white carbon black silica active enhancer, 10 parts of sepiolite, 4.2 parts of cellulose, 6 parts of hydroxypropyl methyl cellulose ether, 1.05 parts of starch ether, 2.5 parts of sodium dodecyl sulfate k12 air-entraining agent, 1.575 parts of NY-12W polyurethane thickening and thixotropic agent, 1.05 parts of building waste fine powder passing through 200 meshes and 882 parts of water;

[0057] S2. Dry-mix and mix evenly the PO42.5 portland cement, expanded perlite, heavy calcium powder, sand, redispersible latex powder, white carbon black silica active enhancer, sepiolite, cellulose, hydroxypropyl methyl cellulose ether, starch ether, sodium dodecyl sulfate k12 air-entraining agent, NY-12W polyurethane thickening and thixotropic agent, and building waste fine powder passing through 200 meshes in step S1 to obtain a dry-mixed material;

[0058] S3. Add water to the dry-mixed material in step S2, then stir at a speed of 140±5 rpm for 2 min, then stir at a speed of 285±10 rpm for 1 min, and finally stir at a speed of 140±5 rpm for 1 min to obtain building waste thermal insulation mortar, denoted as Y1.

[0059] Example 2

[0060] A preparation method of building waste thermal insulation mortar, the steps include:

[0061] S1. Raw material preparation: 560 parts of PO42.5 portland cement, 400 parts of expanded perlite, 52.5 parts of heavy calcium powder, 80 parts of sand, 15.75 parts of redispersible latex powder, 11.55 parts of white carbon black silica active enhancer, 10 parts of sepiolite, 4.2 parts of cellulose, 6 parts of hydroxypropyl methyl cellulose ether, 1.05 parts of starch ether, 2.5 parts of sodium dodecyl sulfate k12 air-entraining agent, 1.575 parts of NY-12W polyurethane thickening and thixotropic agent, 2.1 parts of building waste fine powder passing through 200 meshes and 882 parts of water;

[0062] S2. Dry-mix the PO42.5 portland cement, expanded perlite, heavy calcium powder, sand, redispersible latex powder, white carbon black silica activity enhancer, sepiolite, cellulose, hydroxypropyl methyl cellulose ether, starch ether, sodium dodecyl sulfate k12 air-entraining agent, NY-12W polyurethane thickening and thixotropic agent, and construction waste fine powder passing through 200 meshes in step S1 until evenly mixed to obtain a dry-mix material;

[0063] S3. Add water to the dry-mix material in step S2, then stir at a speed of 140 ± 5 rpm for 2 min, then stir at a speed of 285 ± 10 rpm for 1 min, and finally stir at a speed of 140 ± 5 rpm for 1 min to obtain the construction waste thermal insulation mortar, denoted as Y2.

[0064] Example 3

[0065] A method for preparing a construction waste thermal insulation mortar, the steps comprising:

[0066] S1. Raw material preparation: 560 parts of PO42.5 portland cement, 400 parts of expanded perlite, 52.5 parts of heavy calcium powder, 80 parts of sand, 15.75 parts of redispersible latex powder, 11.55 parts of white carbon black silica activity enhancer, 10 parts of sepiolite, 4.2 parts of cellulose, 6 parts of hydroxypropyl methyl cellulose ether, 1.05 parts of starch ether, 2.5 parts of sodium dodecyl sulfate k12 air-entraining agent, 1.575 parts of NY-12W polyurethane thickening and thixotropic agent, 3.15 parts of construction waste fine powder passing through 200 meshes, and 882 parts of water;

[0067] S2. Dry-mix the PO42.5 portland cement, expanded perlite, heavy calcium powder, sand, redispersible latex powder, white carbon black silica activity enhancer, sepiolite, cellulose, hydroxypropyl methyl cellulose ether, starch ether, sodium dodecyl sulfate k12 air-entraining agent, NY-12W polyurethane thickening and thixotropic agent, and construction waste fine powder passing through 200 meshes in step S1 until evenly mixed to obtain a dry-mix material;

[0068] S3. Add water to the dry-mix material in step S2, then stir at a speed of 140 ± 5 rpm for 2 min, then stir at a speed of 285 ± 10 rpm for 1 min, and finally stir at a speed of 140 ± 5 rpm for 1 min to obtain the construction waste thermal insulation mortar, denoted as Y3.

[0069] Example 4

[0070] A method for preparing a construction waste thermal insulation mortar, the steps comprising:

[0071] S1. Raw material preparation: 560 parts of PO42.5 portland cement, 400 parts of expanded perlite, 52.5 parts of heavy calcium powder, 80 parts of sand, 15.75 parts of redispersible latex powder, 11.55 parts of white carbon black (silica active enhancer), 10 parts of sepiolite, 4.2 parts of cellulose, 6 parts of hydroxypropyl methyl cellulose ether, 1.05 parts of starch ether, 2.5 parts of sodium dodecyl sulfate (k12 air-entraining agent), 1.575 parts of NY-12W polyurethane thickening and thixotropic agent, 4.2 parts of construction waste fine powder passing through 200 meshes, and 882 parts of water;

[0072] S2. Dry-mix and mix evenly the PO42.5 portland cement, expanded perlite, heavy calcium powder, sand, redispersible latex powder, white carbon black (silica active enhancer), sepiolite, cellulose, hydroxypropyl methyl cellulose ether, starch ether, sodium dodecyl sulfate (k12 air-entraining agent), NY-12W polyurethane thickening and thixotropic agent, and construction waste fine powder passing through 200 meshes in step S1 to obtain a dry-mixed material;

[0073] S3. Add water to the dry-mixed material in step S2, then stir at a speed of 140 ± 5 rpm for 2 min, then stir at a speed of 285 ± 10 rpm for 1 min, and finally stir at a speed of 140 ± 5 rpm for 1 min to obtain construction waste thermal insulation mortar, denoted as Y4.

[0074] Example 5

[0075] A preparation method of construction waste thermal insulation mortar, the steps include:

[0076] S1. Raw material preparation: 560 parts of PO42.5 portland cement, 400 parts of expanded perlite, 52.5 parts of heavy calcium powder, 80 parts of sand, 15.75 parts of redispersible latex powder, 11.55 parts of white carbon black (silica active enhancer), 10 parts of sepiolite, 4.2 parts of cellulose, 6 parts of hydroxypropyl methyl cellulose ether, 1.05 parts of starch ether, 2.5 parts of sodium dodecyl sulfate (k12 air-entraining agent), 1.575 parts of NY-12W polyurethane thickening and thixotropic agent, 5.25 parts of construction waste fine powder passing through 200 meshes, and 882 parts of water;

[0077] S2. Dry-mix and mix evenly the PO42.5 portland cement, expanded perlite, heavy calcium powder, sand, redispersible latex powder, white carbon black (silica active enhancer), sepiolite, cellulose, hydroxypropyl methyl cellulose ether, starch ether, sodium dodecyl sulfate (k12 air-entraining agent), NY-12W polyurethane thickening and thixotropic agent, and construction waste fine powder passing through 200 meshes in step S1 to obtain a dry-mixed material;

[0078] S3. Add water to the dry mixture in step S2, then stir at a speed of 140 ± 5 rpm for 2 min, then stir at a speed of 285 ± 10 rpm for 1 min, and finally stir at a speed of 140 ± 5 rpm for 1 min to obtain the construction waste thermal insulation mortar, denoted as Y5.

[0079] Example 6

[0080] Method for preparing construction waste thermal insulation mortar, the steps include:

[0081] S1. Raw material preparation: 560 parts of PO42.5 Portland cement, 400 parts of expanded perlite, 52.5 parts of heavy calcium powder, 80 parts of sand, 15.75 parts of redispersible latex powder, 11.55 parts of silica white carbon black activity enhancer, 10 parts of sepiolite, 4.2 parts of cellulose, 6 parts of hydroxypropyl methyl cellulose ether, 1.05 parts of starch ether, 2.5 parts of sodium dodecyl sulfate k12 air-entraining agent, 1.575 parts of NY-12W polyurethane thickening and thixotropic agent, 6.3 parts of construction waste fine powder passing through 200 meshes, and 882 parts of water;

[0082] S2. Dry mix and uniformly mix the PO42.5 Portland cement, expanded perlite, heavy calcium powder, sand, redispersible latex powder, silica white carbon black activity enhancer, sepiolite, cellulose, hydroxypropyl methyl cellulose ether, starch ether, sodium dodecyl sulfate k12 air-entraining agent, NY-12W polyurethane thickening and thixotropic agent, and construction waste fine powder passing through 200 meshes in step S1 to obtain a dry mixture;

[0083] S3. Add water to the dry mixture in step S2, then first stir at a speed of 140 ± 5 rpm for 2 min, then stir at a speed of 285 ± 10 rpm for 1 min, and finally stir at a speed of 140 ± 5 rpm for 1 min to obtain the construction waste thermal insulation mortar, denoted as Y6.

[0084] Comparative Example 1

[0085] Method for preparing thermal insulation mortar, the steps include:

[0086] S1. Raw material preparation: 560 parts of PO42.5 Portland cement, 400 parts of expanded perlite, 52.5 parts of heavy calcium powder, 80 parts of sand, 15.75 parts of redispersible latex powder, 11.55 parts of silica white carbon black activity enhancer, 10 parts of sepiolite, 4.2 parts of cellulose, 6 parts of hydroxypropyl methyl cellulose ether, 1.05 parts of starch ether, 2.5 parts of sodium dodecyl sulfate k12 air-entraining agent, 1.575 parts of NY-12W polyurethane thickening and thixotropic agent, and 882 parts of water;

[0087] S2. Dry-mix the PO42.5 portland cement, expanded perlite, heavy calcium powder, sand, redispersible latex powder, white carbon black silica activity enhancer, sepiolite, cellulose, hydroxypropyl methyl cellulose ether, starch ether, sodium dodecyl sulfate k12 air-entraining agent, and NY-12W polyurethane thickener and thixotropic agent in step S1 evenly to obtain a dry-mix material;

[0088] S3. Add water to the dry-mix material in step S2, then stir at a speed of 140 ± 5 rpm for 2 min, then stir at a speed of 285 ± 10 rpm for 1 min, and finally stir at a speed of 140 ± 5 rpm for 1 min to obtain thermal insulation mortar, denoted as Y.

[0089] Test Example 1

[0090] Pour the thermal insulation mortar obtained in Examples 1-6 and Comparative Example 1 into a mold for molding. After 48 h, take out the molded sample, place the sample in a curing box for curing. The curing temperature is between 20-25 °C, and the relative humidity is between 80-95%. Cure for 28 d. After the curing is completed, take out the test block, dry it to a constant weight at (105 ± 5) °C. After the temperature drops to room temperature, perform a performance test.

[0091] 1) Thermal conductivity test

[0092] Use a transient plane heat source method thermal conductivity meter to measure the thermal conductivity. Use probe No. 1 (probe resistance 1.323 Ω), set the time to 160 s, adjust the base tone to 0.02-0.03, adjust the power to 0.023-0.200 w. The final result is the average value of 3 groups of sample tests. The results are shown in Table 1.

[0093] Table 1

[0094]

[0095]

[0096] Figure 1 It is the change curve of the thermal conductivity with the increase in the addition amount of construction waste fine powder.

[0097] From Table 1 and Figure 1 it can be seen that with the addition of construction waste fine powder, the thermal conductivity of the construction waste thermal insulation mortar basically shows a trend of first increasing and then decreasing.

[0098] 2) Compressive strength test

[0099] Referring to GB / T 20473-2021 "Building Thermal Insulation Mortar", a hydraulic universal testing machine was used to test the strength of the experimental specimens. The side surface during molding was used as the compression surface. Since the strength of the vitrified microbead thermal insulation material is relatively low, the minimum value that the instrument can reach was adopted for the downward pressure speed: 0.25 kN / s. For some unstable stress peaks, conversion was carried out using the following formula (1) based on the force value. The final result was the average value after testing 3 groups of samples. The compressive strength is shown in Table 2.

[0100]

[0101] In formula (1), F C is the force value, A is the stressed area, and in this experiment, 70.7 mm × 70.7 mm was taken.

[0102] 3) Flexural strength test

[0103] Referring to GB / T 20473-2021 "Building Thermal Insulation Mortar", an electric flexural testing machine was used to test the strength of the experimental specimens. The side surface during molding was used as the compression surface. Since the strength of the vitrified microbead thermal insulation material is relatively low, due to the limitation of the instrument's progress, if the experimental specimen breaks in advance, conversion was carried out using the following formula (2). The final result was the average value after testing 3 groups of samples. The flexural strength is shown in Table 3.

[0104]

[0105] In formula (2), F f is the force value, L is the distance between the centers of the support cylinders, and b and h are the width and height of the specimen cross-section.

[0106] Table 2

[0107]

[0108] Table 3

[0109]

[0110] Figure 2 is the change curve of the mechanical properties with the increase in the addition amount of the fine powder of construction waste.

[0111] Figure 3 are the SEM diagrams of the samples in Examples 1-3. Among them, a is Example 1, b is Example 2, and c is Example 3.

[0112] From Table 2 - Table 3 and Figure 2 - Figure 3 it can be seen that with the addition of the fine powder of construction waste, the compressive strength and flexural strength of the construction waste thermal insulation mortar basically show a trend of first decreasing, then increasing, and then decreasing.

[0113] 4) Linear shrinkage rate test

[0114] The measurement was carried out with reference to GB / T 26000-2010 "Expanded Vermiculite Thermal Insulation Mortar". The prepared thermal insulation mortar was filled into a test mold with dimensions of 40 mm × 40 mm × 160 mm. After demolding, the specimens were placed in a curing box and cured for 28 days according to the above-mentioned curing method. Then the specimens were taken out and put into a drying oven to be dried to a constant weight. The length of each specimen was measured with a vernier caliper, accurate to 0.01 mm, and the linear shrinkage rate was calculated according to the following formula (3). The test result was the average value of 3 specimens, accurate to 0.1%, and for better comparative analysis, in this study, the experimental results were retained to 0.01%, and the results are shown in Table 4.

[0115]

[0116] In formula (3), X is the linear shrinkage rate, %; L 0 is the length at the time of demolding, mm; L 1 is the specimen length at 28 days of curing, mm.

[0117] Table 4

[0118]

[0119]

[0120] Figure 4 is the linear shrinkage rate under the conditions of different addition amounts of fine powder of construction waste.

[0121] From Table 4 and Figure 4 it can be seen that with the increase of the content of fine powder of construction waste, the linear shrinkage rate of the thermal insulation mortar of construction waste shows a trend of first decreasing (Y1 - Y3), then increasing (Y3 - Y4), and finally decreasing again (Y4 - Y6). When the fine powder of construction waste is added, due to the differences in its particle shape, size and surface characteristics from the original mortar materials, the voids inside the mortar increase, resulting in a linear shrinkage rate greater than that of the raw materials. In the process of Y1 - Y3, with the addition of the fine powder of construction waste, it begins to effectively fill the voids in the mortar, fill the tiny pores in the mortar, improve the mix proportion and the degree of hydration of cement, and promote the formation of a denser microstructure. Here, the fine powder helps to enhance the bond between cement particles and reduce the linear shrinkage rate of the thermal insulation mortar. In the process of Y3 - Y4, with the increase of the fine powder of construction waste, the hydration reaction between cement and the fine powder of construction waste decreases, resulting in incomplete hydration and an increase in the shrinkage rate. In the process of Y4 - Y6, the high content of the fine powder of construction waste further refines the microstructure of the mortar, making the fine powder of construction waste and cement form a more stable and dense microstructure, and the optimization of this structure helps to reduce the linear shrinkage of the mortar.

[0122] Test Example 2

[0123] The temperature change experiment of the thermal insulation mortar prepared in Example 3 and Comparative Example 1 during the actual heat conduction process is as follows.

[0124] Set up the experimental bench, number the six sides of the cured test blocks, as Figure 5 shown. Wrap all sides of the test blocks except the S side with thermal insulation cotton to simulate the effects of the inner and outer surfaces of the wall to the greatest extent. At the same time, paste temperature probes on each surface, and add environmental temperature probes to record the change of the surrounding environment temperature (HJWD) of the test blocks.

[0125] The experiment is carried out in two parts, namely the cooling change process from normal temperature to low temperature and the heating change process from low temperature to normal temperature. The low temperature environment is simulated by adjusting the temperature of the refrigerator.

[0126] 1) Cooling change process of the thermal insulation mortar

[0127] Place the samples at normal temperature in the refrigerator. During the experiment, use a TCP-16 multi-channel temperature recorder to record the temperature change process of the experimental test blocks at intervals of 5 s for a total of 3600 s. According to the data presented by the multi-channel temperature recorder, due to the large amount of data, the experimental data is excerpted in stages of 5 minutes. The excerpted data results are shown in Table 5. Record the temperature change processes of the S and X surfaces. The results are as Figure 5 and Figure 6 shown.

[0128] Figure 6 is the temperature change curve of the S surface; Figure 7 is the temperature change curve of the X surface.

[0129] Table 5 Record of temperature change data during the cooling process of Y and Y3 (℃)

[0130]

[0131] From Figure 6 - Figure 7 and the data in Table 5, it can be seen that in terms of the data representation of the cooling process of the thermal insulation mortar in Example 3 and Comparative Example 1, it is basically positively correlated with the magnitude of the thermal conductivity. The S surface is the contact surface with the environment, and the temperature change curves of Y and Y3 basically coincide. The X surface is the inner bottom surface. Due to the wrapping of thermal insulation cotton around, it can best show the temperature conduction process of the construction waste thermal insulation mortar test block. During the 3600 s process, Y cooled by a total of 25.4 °C, while Y3 cooled by a total of 29.6 °C, which is 1.16 times that of Y, and the values are close.

[0132] Carry out thermal imaging tests on the thermal insulation mortar test blocks of Y and Y3. Through thermal imaging technology, visually observe the temperature change situation at the center of the surface of the thermal insulation mortar.

[0133] The experimental specimen was placed in an environment of 0°C from an environment of 33°C. The temperature at the center point of the specimen was recorded every two minutes using a digital infrared thermal imager for a total of 20 minutes to observe the induction rate of the construction waste thermal insulation mortar specimen to the surrounding low-temperature environment. The results are shown in Table 6 and Figure 8 as follows.

[0134] Figure 8 Figure for comparing the temperature drop curves at the center of the thermal insulation mortar specimens of Y and Y3. Figure 9 Thermal imaging diagram at the center of the thermal insulation mortar specimens of Y and Y3.

[0135] Table 6

[0136]

[0137] From Figure 8 - Figure 9 the data in and Table 6, it can be seen that the temperature change of the Y3 construction waste thermal insulation mortar within 20 minutes is slightly lower than that of the Y thermal insulation mortar, proving that the induction rate of the Y3 construction waste thermal insulation mortar to the surrounding cold environment is slower. In the above content, the heat storage coefficient of the Y3 construction waste thermal insulation mortar was measured to be 1.13171 W / (m2·k), and the specific heat capacity was 0.76418 KJ / (Kg·k), both of which are higher than those of the Y thermal insulation mortar (the heat storage coefficient is 1.06049 W / (m2·k), and the specific heat capacity is 0.74518 KJ / (Kg·k)). Due to the larger specific heat capacity and heat storage coefficient, the Y3 construction waste thermal insulation mortar can store more heat. When the Y thermal insulation mortar and the Y3 series of construction waste thermal insulation mortars are simultaneously placed from room temperature into an environment of 0°C, due to the smaller thermal conductivity coefficient of the Y mortar, its heat transfer ability to the external cold environment is weaker, so its cooling rate is relatively slower. However, the larger specific heat capacity and heat storage coefficient of the Y3 construction waste thermal insulation mortar make it conduct heat faster, but due to its strong heat storage capacity, the rate of heat release during the cooling process is slower than that of the Y thermal insulation mortar.

[0138] 2) Heating change process of the thermal insulation mortar

[0139] After the above cooling change test was completed, the experimental samples were immediately placed at room temperature, and the heating process of the thermal insulation mortar specimens was observed. A TCP-16 multi-channel temperature recorder was used to record the temperature change process of the experimental specimens at intervals of 5 s for a total of 3600 s. According to the data presented by the multi-channel temperature recorder, due to the large amount of data, the experimental data was excerpted in stages of 5 minutes. The excerpted data results are shown in Table 7. The temperature change processes of the S and X surfaces were recorded, and the results are as Figure 10 and Figure 11 as follows.

[0140] Figure 10 is the temperature change curve of the S surface; Figure 11 is the temperature change curve of the X surface.

[0141] Table 7 Temperature change data record during the heating process of Y and Y3 (°C)

[0142]

[0143] From Figure 10 - Figure 11 and the data in Table 7, it can be seen that the temperature change of the X surface of Y3 construction waste thermal insulation mortar is 14.1 °C within 3600 s, while the temperature change of the X surface of Y thermal insulation mortar is 23.53 °C within 3600 s. At the end of the above cooling experiment, the final temperature of Y thermal insulation mortar is 0.2 °C, and the final temperature of Y3 construction waste thermal insulation mortar is -4.1 °C. After the above experiment, the experimental space needs to be replaced, and the experimental samples are placed in a normal temperature environment. Due to the sensitivity of the temperature probe, there is a time difference of about 2 minutes after the samples are fixed during the heating process of the construction waste thermal insulation mortar. After this two-minute time difference, the temperature of the X surface of Y still remains at -1.1 °C (the instrument parameters need to be modified during the process from the end of the experiment to the removal of the samples. To prevent the experimental samples from heating up and affecting the experimental results, the samples are still placed in the refrigerator environment), but the temperature of the X surface of Y3 has risen to 10.7 °C. Just from this point, it can be directly seen that the temperature transfer process of Y is slower than that of Y3. At the same time, at 0 s in the experimental record, the temperature difference between Y and the ambient temperature is 26.7 °C, while that of Y3 is only 14.9 °C. The difference in the temperature difference between the two also leads to different amounts of heat conducted through this area per unit time, so the phenomenon shown in Figure 10 - Figure 11 appears.

[0144] During the heating process, thermal imaging tests were conducted on the test blocks of Y and Y3 thermal insulation mortars. Through thermal imaging technology, the temperature change of the center of the surface of the thermal insulation mortar was visually observed. The temperature of the center point of the test block was recorded every two minutes using a digital infrared thermal imager for a total of 20 minutes to observe the induction rate of the construction waste thermal insulation mortar test block to the surrounding high-temperature environment. The results are shown in Table 8 and Figure 12 as shown.

[0145] Figure 12 Figure for comparing the heating curves at the center of the test blocks of Y and Y3 thermal insulation mortars. Figure 13 Thermal imaging diagrams at the center of the test blocks of Y and Y3 thermal insulation mortars.

[0146] Table 8

[0147]

[0148] From Figure 12 - Figure 13As can be seen from Table 8, during the heating process, the temperature changes of the Y thermal insulation mortar and the Y3 thermal insulation mortar are very close. The initial temperature of the test point of the Y thermal insulation mortar is 25.2 °C, and the final temperature is 51.2 °C. In 20 minutes, the Y thermal insulation mortar has a total temperature increase of 26 °C. Similarly, the initial temperature of the test point of the Y3 thermal insulation mortar is 24.5 °C, and the final temperature is 51.1 °C. In 20 minutes, the Y3 thermal insulation mortar has a total temperature increase of 26.6 °C. The difference between the two is only 0.6 °C, proving that the induction effects of the Y and Y3 thermal insulation mortars on the thermal environment are similar. For the temperature changes at some points, for example, at 10 minutes, it can be clearly seen from the figure that when the surrounding environment changes suddenly, the fluctuations of Y3 will be more intense.

[0149] In summary, the overall cooling and heating processes of the Y and Y3 thermal insulation mortars are basically positively correlated with the magnitude of the thermal conductivity, which is basically consistent with the experimental results measured in the above experiments;

[0150] Due to the large specific heat capacity and heat storage coefficient of the Y3 construction waste thermal insulation mortar, it can store more heat. When the Y thermal insulation mortar and the Y3 construction waste thermal insulation mortar are simultaneously placed in an environment of 0 °C from room temperature, the Y mortar has a weak heat transfer ability to the external cold environment due to its small thermal conductivity, so its cooling rate is slower. However, due to the large specific heat capacity and heat storage coefficient of the Y3 construction waste thermal insulation mortar, although its thermal conductivity is fast, its ability to store heat is strong, making the rate of heat release during the cooling process slower than that of the Y thermal insulation mortar. The heat storage coefficient and specific heat capacity of the material affect the overall heat storage and heat release capabilities of the material. The larger the values of the two, the better the ability. However, for the rapid change of local temperature difference, the material with a large thermal conductivity will respond faster.

[0151] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0152] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A building waste thermal insulation mortar, characterized in that: The raw materials include: solid components, admixtures and water; The solid components include, by mass: 40 parts of vitrified microspheres, 50 parts of cement, 8 parts of sand and 2 parts of sepiolite; The mass ratio of water to solid components is 0.84:1; The amount of the additive added is 85‰-97.5‰ of the mass of the solid component; The admixtures include rubber powder, cellulose, starch ether, thixotropic agent, activator, air entraining agent, heavy calcium powder, cellulose ether and construction waste fine powder, and the mass ratio is 15:4:1:1.5:11:(0.5-3):50:(1-6):(1-6).

2. The construction waste thermal insulation mortar according to claim 1, characterized in that: The cement is PO42.5 silicate cement.

3. The construction waste thermal insulation mortar according to claim 1, characterized in that: The bulk density of the sand is 1.6 g / cm 3 , the mud content is 1.5%; and / or the bulk density of the sepiolite is 1000-2200 kg / m 3 , specific surface area is 350kg / m 2 ; and / or, the bulk density of the vitrified microspheres is 90-110 kg / m 3 , thermal conductivity is 0.037W·m -1 ·K -1 , particle size is 0.5-1.5mm.

4. The construction waste thermal insulation mortar according to claim 1, characterized in that: The rubber powder is dispersible latex powder and / or vinyl acetate and ethylene copolymer rubber powder.

5. The construction waste thermal insulation mortar according to claim 1, characterized in that: The active agent is white carbon black silicon dioxide activity enhancer; and / or, the cellulose ether is hydroxypropyl methyl cellulose ether.

6. The construction waste thermal insulation mortar according to claim 1, characterized in that: The air entraining agent is sodium dodecyl sulfate K12 air entraining agent; and / or, the thixotropic agent is NY-12W polyurethane thickening thixotropic agent.

7. The construction waste thermal insulation mortar according to claim 1, characterized in that: The construction waste fine powder is the material that passes through a 200-mesh sieve after crushing concrete waste.

8. A method for preparing the building waste thermal insulation mortar according to any one of claims 1 to 7, characterized in that the steps include: The cement, vitrified microspheres, heavy calcium powder, sand, rubber powder, active agent, sepiolite, cellulose, cellulose ether, starch ether, air entraining agent, thixotropic agent and construction waste fine powder are dry-mixed and uniformly mixed, and then water is added and stirred uniformly to obtain the construction waste thermal insulation mortar.

9. The preparation method according to claim 8, characterized in that: The stirring is firstly stirring at a rotation speed of 130-150 rpm for 2 min, then stirring at a rotation speed of 270-300 rpm for 1 min, and finally stirring at a rotation speed of 130-150 rpm for 1 min.

10. Use of the construction waste thermal insulation mortar as claimed in any one of claims 1 to 7 in the construction of energy-saving buildings.

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