Decoration waste aerogel thermal insulation mortar with same service life as building structure in partial freezing area and preparation method of decoration waste aerogel thermal insulation mortar

Abstract

The invention relates to the technical field of building materials, and discloses decoration waste aerogel thermal insulation mortar with the same service life as a building structure in a partial freezing area and a preparation method of the decoration waste aerogel thermal insulation mortar. The decoration waste aerogel thermal insulation mortar with the same service life as the building structure in the slightly frozen area is prepared from the following components in parts by weight: 282 to 1128 parts of decoration waste recycled aggregate, 79 to 131 parts of SiO2 aerogel, 7.9 to 13.1 parts of silane coupling agent, 908 parts of P.O42.5-grade cement, 89.8 parts of silica fume, 404 parts of water, 1 part of air entraining agent and 10 parts of water reducing agent. The thermal insulation mortar prepared according to the proportion can meet the application requirements of partial freezing areas, shows excellent anti-freezing durability and thermal insulation effect, and can have the same service life as a building structure. When the mortar is applied to thermal insulation engineering of building outer walls in partial freezing areas, durability and thermal insulation effect are guaranteed, the service life of the mortar is the same as that of a building, the service life of the building is greatly prolonged, and repair and maintenance cost is reduced. And considerable economic benefits and environmental protection benefits are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas and a preparation method thereof. Background Technique

[0002] Slightly frozen areas are widely distributed in most parts of China. In these areas, the winter temperature is relatively low, and the surface layer of soil or water body will experience short-term freezing, but the freezing depth is relatively shallow and the duration is not long. However, it still causes irreversible damage to the microstructure of cement-based materials, resulting in the degradation of their thermal insulation performance. Generally speaking, the internal structure damage caused by freeze-thaw cycles is the fundamental reason for the performance decline of thermal insulation mortar. Under the action of freeze-thaw, the micropores and cracks in the thermal insulation mortar gradually increase, and some pores are invaded by water, resulting in an increase in the thermal conductivity coefficient, thus affecting its thermal insulation effect. In addition, the increase of these micro-pores makes the heat conduction path longer, reducing the thermal insulation efficiency of the material and further weakening the thermal insulation ability of the mortar. Existing research has demonstrated that 15 times of accelerated freeze-thaw tests is equivalent to 50 years of actual environmental service.

[0003] At the same time, the discharge of decoration waste in slightly frozen areas is increasing day by day. According to statistics, the annual output of decoration waste in China exceeds 54.72 million tons, and the treatment cost is as high as 21.8 billion yuan. Decoration waste comes from the soil, waste materials and other waste generated in residential or commercial decoration. Its sources are scattered, the quantity is scattered, the generation frequency is high, and the components are randomly distributed, which increases the difficulty of resource utilization. At present, the comprehensive utilization rate of decoration waste in China is less than 5%, and the disposal methods are mainly open-air stacking, landfill or incineration, which not only occupy a large amount of land, but also seriously damage the ecological environment. Treating decoration waste into recycled aggregates through processes such as sorting, crushing, and screening, and partially or completely replacing natural sand and gravel to prepare green building materials is an effective way of its resource utilization. Compared with natural aggregates, the recycled aggregates of decoration waste have the characteristics of high porosity, low density, large water absorption, and strong regional dependence. They belong to typical lightweight aggregates and are particularly suitable for on-site recycled utilization in external wall thermal insulation projects.

[0004] The ability of the external wall thermal insulation and heat insulation system to perform the functions of comfort and fire safety mainly depends on the thermal insulation material. At present, inorganic thermal insulation mortar has become the first choice for external wall thermal insulation and heat insulation systems due to its good durability and high fire protection level. However, in recent years, building fires have occurred frequently, and the fire level and frequency have shown an upward trend. The problem of insufficient fire safety of external wall thermal insulation mortar is very prominent, and typical diseases such as cracking and falling off under fire generally occur, which not only causes the premature loss of functions such as thermal insulation and reduces comfort, but also leads to the inability of the building to be used normally or even collapse, resulting in a large number of casualties. At the same time, the service life of the thermal insulation system being less than the service life of the building structure also causes economic losses.

[0005] Chinese Patent CN117069462A discloses an aerogel thermal insulation mortar and its preparation method. By incorporating the prepared aerogel particles into the cement mortar, the thermal conductivity of the mortar is reduced. However, the aerogel prepared without surfactant treatment results in poor bonding between the aerogel and the cement paste, leading to unsatisfactory mechanical properties. Chinese Patent CN116239356A discloses a decoration waste aerogel thermal insulation mortar and its preparation method. However, to improve the mortar performance, a large amount of admixtures are added to the prepared mortar, greatly increasing the cost of the finished mortar and being unfavorable for its application in actual projects. Meanwhile, the above patents do not address whether the performance of the thermal insulation mortar serving in slightly frozen regions still meets the actual needs under fire conditions.

[0006] Therefore, it is particularly important to develop a thermal insulation mortar material that can meet the application requirements in slightly frozen regions, has excellent freeze-thaw durability and thermal insulation effect, and has the same service life as the building structure. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen regions and its preparation method. The thermal insulation mortar of the present invention uses decoration waste recycled aggregate as the main raw material, combines high-quality thermal insulation materials such as SiO2 aerogel, and through the adoption of the preparation method of the present invention, realizes the thermal insulation effect with the same service life as the building structure, greatly reducing the maintenance and repair costs. In addition, when used in the external wall thermal insulation project in slightly frozen regions, the thermal insulation mortar also has excellent freeze-thaw durability and fire resistance.

[0008] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0009] A decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen regions, specifically including the following components in parts by weight: 282 - 1128 parts of decoration waste recycled aggregate, 79 - 131 parts of SiO2 aerogel, 7.9 - 13.1 parts of silane coupling agent, 908 parts of P·O42.5 grade cement, 89.8 parts of silica fume, 404 parts of water, 1 part of air-entraining agent, and 10 parts of water-reducing agent.

[0010] By optimizing the proportion of each component, the aerogel thermal insulation mortar ensures excellent freeze-thaw resistance, thermal insulation and mechanical properties. The addition of decoration waste recycled aggregate significantly improves the resource utilization rate and reduces the environmental burden. The synergistic effect of SiO2 aerogel and silane coupling agent significantly reduces the thermal conductivity and simultaneously enhances the bonding strength with the cement matrix.

[0011] Furthermore, the cement is P·O42.5 portland cement. This cement has moderate strength, low cost, and strong adaptability, ensuring the mechanical properties and construction performance of the mortar. It has good compatibility with admixtures (such as water reducers and air-entraining agents), optimizes the pore structure, and improves the frost resistance.

[0012] Furthermore, the mass percentage of SiO2 in the recycled aggregate of decoration waste is 37.52%, and the mass percentage of CaO is 34.88%. The high contents of SiO2 and CaO enhance the hydration reaction between the aggregate and the cement, improve the compactness and strength of the mortar, and at the same time reduce the negative impact of harmful components (such as organic matter) on the durability.

[0013] Furthermore, the recycled aggregate of decoration waste is prepared by mixing 1 part of the recycled aggregate of decoration waste with a particle size of 0.075 - 1.18 mm and 2 parts of the recycled aggregate of decoration waste with a particle size of 1.18 - 2.36 mm. This design optimizes the aggregate gradation, reduces the porosity, and improves the compactness and compressive strength of the mortar.

[0014] Furthermore, the mass percentage of SiO2 in the silica fume is 97%. The highly active SiO2 fills the micro-pores, improves the compactness, and reduces the thermal conductivity. At the same time, it promotes the secondary hydration reaction, enhancing the long-term strength and frost resistance.

[0015] Furthermore, the SiO2 aerogel is a hydrophobic SiO2 aerogel with a thermal conductivity of 0.018 W / (m·K). The hydrophobicity reduces the intrusion of moisture, avoids freeze-thaw damage, and the low thermal conductivity significantly improves the thermal insulation performance of the thermal insulation mortar.

[0016] Furthermore, the silane coupling agent is KH550, which enhances the interfacial bonding between the aerogel and the cement matrix, improving the mechanical properties and durability.

[0017] Furthermore, the water reducer is a polycarboxylate superplasticizer. It optimizes the pore structure through electrostatic repulsion and steric hindrance effects, improving the frost resistance and thermal insulation performance.

[0018] Furthermore, the air-entraining agent is a dodecyl sulfonate air-entraining agent. This air-entraining agent introduces uniform micro-bubbles, refines the pores, improves the frost resistance, and at the same time synergistically acts with the water reducer to balance the thermal insulation performance and mechanical properties.

[0019] A preparation method of the above-mentioned thermal insulation mortar of decoration waste aerogel specifically includes the following steps:

[0020] Step S1: Immerse the recycled fine aggregate of decoration waste for 6 h, and then place it in an oven at 105 °C for drying for 3 h until it reaches the saturated surface dry state;

[0021] Step S2: Mix the recycled fine aggregate of decoration waste, P·O 42.5 grade cement, silica fume, air-entraining agent, water-reducing agent and water to obtain the neat mortar of decoration waste;

[0022] Step S3: Add silane coupling agent to the neat mortar of decoration waste prepared in Step S2 and stir evenly to obtain the mortar of decoration waste;

[0023] Step S4: Add hydrophobic SiO2 aerogel particles to the mortar of decoration waste prepared in Step S3 and stir evenly to obtain the finished aerogel thermal insulation mortar of decoration waste.

[0024] The beneficial effects of the present invention are as follows: The present invention is reasonably designed and the preparation method is simple, having the following advantages:

[0025] (1). The hydrophobicity of SiO2 aerogel itself leads to poor compatibility with cement-based materials. The selected KH550 silane coupling agent grafts acrylate groups on the surface of SiO2 aerogel through the dual reactivity of alkoxysilane-inorganic reaction and organic group reaction, making SiO2 aerogel in a state of hydrophilic outside and hydrophobic inside, acting as a bridging agent between SiO2 aerogel and cement substrate to improve the compatibility between the two;

[0026] (2). The modification of KH550 silane coupling agent can improve the interfacial bonding between SiO2 aerogel and cement mortar matrix, make SiO2 aerogel combine tightly with cement paste, and thus can improve the compatibility, mechanical properties and thermal insulation properties between SiO2 aerogel particles and cement mortar matrix;

[0027] (3). The polycarboxylate superplasticizer has a positive effect on the pore structure of mortar. The long-chain polymer molecules in the polycarboxylate avoid particle aggregation through electrostatic repulsion and steric hindrance effects, reduce the formation of large pores, and improve the overall thermal insulation effect;

[0028] (4). The dodecyl sulfonate air-entraining agent introduces tiny and uniform air bubbles into the mortar, changing the pore structure of the mortar, which is beneficial to reducing the density of the mortar to improve its thermal insulation performance; at the same time, this type of air-entraining agent has excellent frost resistance, ensuring the normal use of the mortar in slightly frozen areas;

[0029] (5). The application of polycarboxylate superplasticizer and dodecyl sulfonate air-entraining agent in mortar shows a significant synergistic effect; specifically, the polycarboxylate water-reducing agent makes the cement particles more evenly distributed through its dispersion effect, thus promoting the full progress of cement hydration reaction and generating more dense hydration products; at the same time, the air-entraining agent improves the lightness and heat insulation of the mortar by generating uniform and tiny air bubbles, and then improves its thermal insulation performance. The synergistic effect of the two not only ensures the density and strength of the mortar, but also effectively enhances its thermal insulation performance and optimizes the comprehensive performance of the mortar;

[0030] (6) Existing research has shown that the improvement of the phase composition and micro-structure is the fundamental reason for improving the fire resistance of external thermal insulation mortar for exterior walls. The addition of quantitative silica fume plays a positive role in the phase composition of the insulation mortar made from construction waste aerogel, optimizing its performance.

[0031] (7) The present invention utilizes construction waste for resource utilization to obtain recycled fine aggregates, which are used to replace natural river sand to prepare finished mortar. Aerogel and a small number of types of admixtures are incorporated into the construction waste mortar to prepare thermal insulation mortar, thus putting forward a reasonable solution idea for reducing the waste of construction waste to achieve multiple benefits such as economic energy conservation and environmental protection.

[0032] (8) Bamboo and wood in the construction waste components and plastics after crushing replace fibers in the thermal insulation mortar. While ensuring the workability of the mortar, it improves its crack resistance and durability, and has certain economic benefits.

[0033] (9) The construction waste aerogel thermal insulation mortar prepared by the present invention, which has the same service life as the building structure in slightly frozen areas, has good mechanical properties, excellent fire resistance while ensuring its freeze-thaw durability and thermal insulation effect, and reaches the same service life as the building structure in slightly frozen areas, and can be widely applied to the exterior wall thermal insulation project of building structures in slightly frozen areas. Detailed Embodiments

[0034] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] A decoration waste aerogel thermal insulation mortar with a service life equivalent to that of a building structure in a slightly frozen area specifically comprises the following components in parts by weight: 282-1128 parts of decoration waste recycled aggregate, 79-131 parts of SiO2 aerogel, 7.9-13.1 parts of silane coupling agent, 908 parts of P·O42.5 grade cement, 89.8 parts of silica fume, 404 parts of water, 1 part of air entraining agent, and 10 parts of water reducing agent.

[0038] The cement is P·O42.5 silicate cement. This type of cement has a lower density, plays a positive role in the thermal insulation performance of the thermal insulation mortar, has good adaptability to the added additives and has a lower cost.

[0039] The mass percentage of SiO2 in the decoration waste recycled aggregate is 37.52%, and the mass percentage of CaO is 34.88%. The components of the decoration waste recycled aggregate used to prepare the thermal insulation mortar are mainly bricks, concrete, glass, etc., mixed with plastics, bamboo and wood, etc.

[0040] The decoration waste recycled aggregate is made by mixing 1 part of decoration waste recycled aggregate with a particle size of 0.075-1.18mm and 2 parts of decoration waste recycled aggregate with a particle size of 1.18-2.36mm. Both particle sizes of decoration waste recycled aggregate belong to the medium-coarse sand in Zone II specified in GB / T 14684-2022 "Construction Sand" and are in a saturated surface dry state.

[0041] The mass percentage of SiO2 in silica fume is 97%, which plays a positive role in the phase composition of the decoration waste aerogel thermal insulation mortar and optimizes its performance.

[0042] SiO2 aerogel uses commercial hydrophobic SiO2 aerogel produced by Guangdong Elison Company, which has a thermal conductivity of 0.018W / (m·K), which can effectively reduce the thermal conductivity of mortar and improve its thermal insulation effect.

[0043] The grade of silane coupling agent is KH550. With the silane coupling agent, the contact angle of aerogel particles before modification is 145°, while the contact angle after modification becomes 87°, realizing the hydrophilic outer and hydrophobic inner structure, and making the modified SiO2 aerogel particles and mortar effectively bonded.

[0044] The water reducer is a polycarboxylic acid high-performance water reducer. The water reducing efficiency of the water reducer is 40%. The long-chain polymer molecules in the polycarboxylic acid molecules disperse the cement particles more evenly through electrostatic repulsion and steric hindrance effects, thereby reducing uneven coagulation and hydration reactions during the curing process, avoiding large particles from agglomerating to form larger voids or pores, and improving the thermal insulation and mechanical properties of the mortar.

[0045] The air-entraining agent is a dodecyl sulfonate air-entraining agent. This air-entraining agent has excellent frost resistance. In addition, while introducing air into the mortar, this air-entraining agent refines the large pores inside it, improving its performance.

[0046] A preparation method of the aerogel thermal insulation mortar for decoration waste as described above specifically includes the following steps:

[0047] Step S1: Immerse the recycled fine aggregate of decoration waste for 6 hours, and then place it in an oven at 105°C for drying for 3 hours until it reaches the saturated surface dry state;

[0048] Step S2: Stir the recycled fine aggregate of decoration waste, P·O42.5 grade cement, silica fume, air-entraining agent, water-reducing agent and water to obtain the net paste of decoration waste mortar;

[0049] Step S3: Add a silane coupling agent to the net paste of decoration waste mortar prepared in Step S2 and stir evenly to obtain the decoration waste mortar;

[0050] Step S4: Add hydrophobic SiO2 aerogel particles to the decoration waste mortar prepared in Step S3 and stir evenly to obtain the finished aerogel thermal insulation mortar for decoration waste.

[0051] Example 1

[0052] A preparation method of the aerogel thermal insulation mortar for decoration waste with the same service life as the building structure in slightly frozen areas specifically includes the following steps:

[0053] (1). Determine the mix proportion of the aerogel thermal insulation mortar for decoration waste in this example. Fix the volume of the aggregate (recycled aggregate of decoration waste + aerogel) at 60% of the total volume of the mortar, and the volume admixture of aerogel in the aggregate is 60%; The following components of the aerogel thermal insulation mortar for decoration waste are in parts by mass: 908 parts of P·O42.5 grade cement, 89.8 parts of silica fume, 404 parts of water, 1 part of air-entraining agent, 10 parts of water-reducing agent, 1128 parts of recycled aggregate of decoration waste, 79 parts of SiO2 aerogel, and 7.9 parts of silane coupling agent;

[0054] (2). Prepare the above-mentioned aerogel thermal insulation mortar for decoration waste and cure it; Load the prepared mortar into a mold, demold it after standing at room temperature for 24 hours, and place it in a standard curing room for curing for 28 days; Measure the thermal conductivity of the mortar according to GB / T10294-2008 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials"; In addition, test the compressive-shear bond strength of the mortar and the mass loss of the specimen under the action of a simulated fire at 850°C for 3 hours;

[0055] (3) Take out the above-mentioned decoration waste aerogel thermal insulation mortar after simulating 30 freeze-thaw cycles according to the specification GB / T 35169-2017 "Test Method for Weather Resistance of External Thermal Insulation Systems for Building Exterior Walls", and dry it. After complete drying, measure the thermal conductivity of the mortar according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials". In addition, test the compressive-shear bond strength of the mortar.

[0056] Example 2

[0057] A preparation method of decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas is as follows:

[0058] (1) Determine the mix ratio of the decoration waste aerogel thermal insulation mortar in this example. Fix the volume of the aggregate (decoration waste recycled aggregate + aerogel) at 60% of the total volume of the mortar, and the volume admixture of aerogel in the aggregate is 70%. The following components of the decoration waste aerogel thermal insulation mortar are in parts by mass: 908 parts of P·O 42.5 grade cement, 89.8 parts of silica fume, 404 parts of water, 1 part of air-entraining agent, 10 parts of water-reducing agent, 846 parts of decoration waste recycled aggregate, 92 parts of SiO2 aerogel, and 9.2 parts of silane coupling agent;

[0059] (2) Prepare the above-mentioned decoration waste aerogel thermal insulation mortar and cure it; put the prepared mortar into a mold, demold it after standing at room temperature for 24 hours, and cure it in a standard curing room for 28 days; measure the thermal conductivity of the mortar according to GB / T10294-2008 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials". In addition, test the compressive-shear bond strength of the mortar and the mass loss of the specimen under the action of a simulated fire at 850 °C for 3 hours;

[0060] (3) Take out the above-mentioned decoration waste aerogel thermal insulation mortar after simulating 30 freeze-thaw cycles according to the specification GB / T 35169-2017 "Test Method for Weather Resistance of External Thermal Insulation Systems for Building Exterior Walls", and dry it. After complete drying, measure the thermal conductivity of the mortar according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials". In addition, test the compressive-shear bond strength of the mortar.

[0061] Example 3

[0062] A preparation method of decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas is as follows:

[0063] (1). Determine the mix ratio of the decoration waste aerogel thermal insulation mortar in this embodiment. Fix the volume of the aggregate (decoration waste recycled aggregate + aerogel) at 60% of the total volume of the mortar, and the volume admixture of aerogel in the aggregate is 80%. The following components of the decoration waste aerogel thermal insulation mortar are in parts by mass: 908 parts of P·O 42.5 grade cement, 89.8 parts of silica fume, 404 parts of water, 1 part of air-entraining agent, 10 parts of water-reducing agent, 564 parts of decoration waste recycled aggregate, 105 parts of SiO₂ aerogel, and 10.5 parts of silane coupling agent;

[0064] (2). Prepare the above-mentioned decoration waste aerogel thermal insulation mortar and cure it. Load the prepared mortar into a mold, demold it after standing at room temperature for 24 hours, and place it in a standard curing room for 28 days. Measure the thermal conductivity of the mortar according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials". In addition, test the compression-shear bond strength of the mortar and the mass loss of the specimen under the action of a simulated fire at 850 °C for 3 hours;

[0065] (3). Take out the above-mentioned decoration waste aerogel thermal insulation mortar after simulating 30 freeze-thaw cycles according to the specification GB / T 35169-2017 "Test Method for Weather Resistance of External Thermal Insulation Systems for Building Exterior Walls", and dry it. After complete drying, measure the thermal conductivity of the mortar according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials". In addition, test the compression-shear bond strength of the mortar.

[0066] Example 4

[0067] A preparation method of a decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas is as follows:

[0068] (1). Determine the mix ratio of the decoration waste aerogel thermal insulation mortar in this embodiment. Fix the volume of the aggregate (decoration waste recycled aggregate + aerogel) at 60% of the total volume of the mortar, and the volume admixture of aerogel in the aggregate is 90%. The following components of the decoration waste aerogel thermal insulation mortar are in parts by mass: 908 parts of P·O 42.5 grade cement, 89.8 parts of silica fume, 404 parts of water, 1 part of air-entraining agent, 10 parts of water-reducing agent, 282 parts of decoration waste recycled aggregate, 118 parts of SiO₂ aerogel, and 11.8 parts of silane coupling agent;

[0069] (2). Prepare the above-mentioned decoration waste aerogel thermal insulation mortar and cure it. Load the prepared mortar into a mold, demold it after standing at room temperature for 24 hours, and place it in a standard curing room for 28 days. Measure the thermal conductivity of the mortar according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials". In addition, test the compression-shear bond strength of the mortar and the mass loss of the specimen under the action of a simulated fire at 850 °C for 3 hours;

[0070] (3) Take out the above decoration waste aerogel thermal insulation mortar after simulating 30 freeze-thaw cycles according to the specification GB / T 35169-2017 "Test Method for Weather Resistance of External Thermal Insulation Systems for Building Exterior Walls", and dry it. After complete drying, measure the thermal conductivity of the mortar according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials"; in addition, test the compression-shear bond strength of the mortar.

[0071] Example 5

[0072] A preparation method of decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas, the specific steps are as follows:

[0073] (1) Determine the mix ratio of the decoration waste aerogel thermal insulation mortar in this example, and fix the volume of the aggregate (decoration waste recycled aggregate + aerogel) at 60% of the total volume of the mortar, and the volume admixture of aerogel in the aggregate is 100%; the following components of the decoration waste aerogel thermal insulation mortar are in parts by mass, 908 parts of P·O42.5 grade cement, 89.8 parts of silica fume, 404 parts of water, 1 part of air-entraining agent, 10 parts of water-reducing agent, 131 parts of SiO2 aerogel, 13.1 parts of silane coupling agent;

[0074] (2) Prepare the above decoration waste aerogel thermal insulation mortar and cure it; put the prepared mortar into a mold, demold it after standing at room temperature for 24h, and put it into a standard curing room for 28d; measure the thermal conductivity of the mortar according to GB / T10294-2008 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials"; in addition, test the compression-shear bond strength of the mortar and the mass loss of the specimen under the action of simulating a fire at 850°C for 3h;

[0075] (3) Take out the above decoration waste aerogel thermal insulation mortar after simulating 30 freeze-thaw cycles according to the specification GB / T 35169-2017 "Test Method for Weather Resistance of External Thermal Insulation Systems for Building Exterior Walls", and dry it. After complete drying, measure the thermal conductivity of the mortar according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials"; in addition, test the compression-shear bond strength of the mortar.

[0076] Comparative Example 1

[0077] A preparation method of mortar, the specific steps are as follows:

[0078] (1) The following components of this mortar are in parts by mass, 1009 parts of P·O42.5 grade cement, 404 parts of water, 1 part of air-entraining agent, 10 parts of water-reducing agent, 2819 parts of decoration waste recycled aggregate;

[0079] (2) Prepare the above-mentioned mortar and cure it. Fill the prepared mortar into a mold, let it stand at room temperature for 24 hours and then remove the mold, and cure it in a standard curing room for 28 days. Measure the thermal conductivity of the mortar according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials". In addition, test the compressive-shear bond strength of the mortar;

[0080] (3) Take out the above-mentioned mortar after simulating 30 freeze-thaw cycles according to the standard GB / T 35169-2017 "Test Method for Weather Resistance of External Thermal Insulation Systems for Building Exterior Walls" and dry it. After it is completely dry, measure the thermal conductivity of the mortar according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials". In addition, test the compressive-shear bond strength of the mortar and the mass loss of the specimen under the action of a simulated fire at 850 °C for 3 hours.

[0081] Comparative Example 2

[0082] A method for preparing mortar, the specific steps are as follows:

[0083] (1) Determine the mortar mix ratio of this comparative example. Fix the volume of the aggregate (recycled aggregate from decoration waste + aerogel) at 60% of the total volume of the mortar, and the volume fraction of aerogel in the aggregate is 60%. The following components of this mortar are in parts by mass: 1009 parts of P·O 42.5 grade cement, 404 parts of water, 1 part of air-entraining agent, 10 parts of water-reducing agent, 1128 parts of recycled aggregate from decoration waste, 79 parts of SiO2 aerogel, and 2 parts of silane coupling agent;

[0084] (2) Prepare the above-mentioned mortar and cure it. Fill the prepared mortar into a mold, let it stand at room temperature for 24 hours and then remove the mold, and cure it in a standard curing room for 28 days. Measure the thermal conductivity of the mortar according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials". In addition, test the compressive-shear bond strength of the mortar and the mass loss of the specimen under the action of a simulated fire at 850 °C for 3 hours;

[0085] (3) Take out the above-mentioned mortar after simulating 30 freeze-thaw cycles according to the standard GB / T 35169-2017 "Test Method for Weather Resistance of External Thermal Insulation Systems for Building Exterior Walls" and dry it. After it is completely dry, measure the thermal conductivity of the mortar according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials". In addition, test the compressive-shear bond strength of the mortar.

[0086] Comparative Example 3

[0087] A method for preparing mortar, the specific steps are as follows:

[0088] (1). Determine the mortar mix ratio for this comparative example. Fix the volume of the aggregate (recycled aggregate from construction waste + aerogel) at 60% of the total volume of the mortar, and the volume dosage of aerogel in the aggregate is 60%. The following components of this mortar are in parts by mass: 975 parts of P·O 42.5 grade cement, 30 parts of silica fume, 404 parts of water, 1 part of air-entraining agent, 10 parts of water reducer, 1128 parts of recycled aggregate from construction waste, 79 parts of SiO₂ aerogel, and 2 parts of silane coupling agent.

[0089] (2). Prepare the above mortar and cure it. Load the prepared mortar into a mold, demold it after standing at room temperature for 24 h, and place it in a standard curing room for 28 d. Measure the thermal conductivity of the mortar according to GB / T 10294-2008 Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials. In addition, test the compressive-shear bond strength of the mortar and the mass loss of the specimen under the action of a simulated fire at 850 °C for 3 h.

[0090] (3). Take out the above mortar after simulating 30 freeze-thaw cycles according to the specification GB / T 35169-2017 Test Method for Weather Resistance of External Thermal Insulation Systems for Building Exterior Walls, and dry it. After complete drying, measure the thermal conductivity of the mortar according to GB / T 10294-2008 Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials. In addition, test the compressive-shear bond strength of the mortar.

[0091] The finished products prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were subjected to test and detection, and the test results are shown in Table 1.

[0092] Table 1 Test Results of Examples 1 to 5 and Comparative Examples 1 to 3

[0093]

[0094]

[0095] As can be seen from Table 1, for the thermal insulation mortar prepared in Examples 1 to 5, the compressive-shear bond strength and thermal conductivity before and after freeze-thaw damage both meet the specification requirements.

[0096] Based on existing common knowledge and combined with the annual average temperature, temperature difference, and annual average number of freeze-thaw cycles in slightly frozen areas, it can be deduced that: under the rapid freeze-thaw conditions in the laboratory, the experimental results of 15 freeze-thaw cycles are equivalent to the damage experienced by the mortar in the actual slightly frozen environment under 50 years of freeze-thaw cycles. On this basis, the recycled aggregate aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas prepared in the present invention was subjected to 30 rapid freeze-thaw cycle experiments. The results show that after 30 freeze-thaw cycles, the performance of the mortar still meets the relevant specification requirements. Therefore, it can be considered that the service life of this material is equivalent to that of the building structure in slightly frozen areas.

[0097] As can be seen from Table 1, by comparing Examples 1 to 5 and Comparative Examples 1 to 3, it can be concluded that although the mechanical properties of Comparative Examples 1 to 3 are good, their thermal insulation properties are poor, all of which are greater than the requirements for Type II thermal insulation mortar in GB / T 20473-2021 "Building Thermal Insulation Mortar" (thermal conductivity ≤ 0.085W / (m·K)). In Examples 1 to 5, as the amount of SiO2 aerogel increases, the thermal conductivity of the mortar gradually decreases, meeting the requirements for Type II thermal insulation mortar in the specification. Among them, Examples 3 to 5 also meet the requirements for Type I thermal insulation mortar in the specification (thermal conductivity ≤ 0.070W / (m·K)). However, with the increase in the amount of aerogel, the loss of bonding strength is inevitably caused, but it is still within the scope of the specification requirements. In summary, the decoration garbage aerogel thermal insulation mortar prepared by the present invention, which has the same lifespan as the building structure in the slightly frozen area, shows significant advantages in the performance of the finished product, and has superiority in both thermal insulation and mechanical properties.

[0098] Specifically, the mass loss of Comparative Examples 1 to 2 under freeze-thaw damage and fire was more than 17%, and the insulation mortar fell off the matrix of the structural exterior wall, and no longer had the ability to continue to serve. In contrast, in Examples 1 to 5, under the synergistic effect of component regulation and preparation method, the exterior insulation mortar for the exterior wall of the decoration waste has good insulation performance and bonding strength, and can resist freeze-thaw damage in slightly frozen areas in actual working conditions. The loss of bonding strength after freeze-thaw and the mass loss after fire are lower than those of Comparative Examples 1 to 3. In Comparative Example 3, due to the fact that the amount of silane coupling agent used in the preparation method is less than that of the decoration waste insulation mortar with the same aerogel content, the hydrophobic aerogel particles are not tightly combined with the cement-based material, and the bonding strength of the decoration waste insulation mortar with the same aerogel content is significantly better than that of the decoration waste insulation mortar with the same aerogel content.

[0099] In general, Examples 3 to 5 have better overall performance, not only having low thermal conductivity, but also showing relatively excellent antifreeze durability. The test results before and after freeze-thaw cycles show that while Examples 3 to 5 maintain low thermal conductivity, they can still ensure excellent thermal insulation and mechanical properties after freeze-thaw damage, avoiding technical defects caused by too little addition of aerogel.

[0100] In addition, Examples 3 to 5 are compared horizontally. Example 5 performs the best among all the examples, showing excellent thermal insulation performance. Although its mechanical properties have declined to achieve this excellent performance, the decline is small and still meets the requirements of the specification. Compared with Comparative Examples 1 to 3, Example 5 has a significant improvement in thermal insulation performance, reaching 139.06% to 220.31%.

[0101] The thermal insulation mortar prepared by the present invention is used for the external thermal insulation project of the exterior wall of a building structure, which is conducive to the resource recycling of decoration waste, and can also solve problems such as cracking and peeling of the thermal insulation mortar during its service life. It can achieve the same service life as the building structure, effectively reducing the subsequent maintenance and repair costs, and having considerable economic and environmental benefits.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas, characterized in that: Specifically, it includes the following components in parts by weight: 282 - 1128 parts of recycled aggregate from decoration waste, 79 - 131 parts of SiO₂ aerogel, 7.9 - 13.1 parts of silane coupling agent, 908 parts of P·O 42.5 grade cement, 89.8 parts of silica fume, 404 parts of water, 1 part of air-entraining agent, and 10 parts of water-reducing agent.

2. The aerogel thermal insulation mortar for decoration waste with the same service life as the building structure in slightly frozen areas according to claim 1, characterized in that: The cement is P·O 42.5 portland cement.

3. A decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas according to claim 1, characterized in that: The mass percentage of SiO₂ in the recycled aggregate from decoration waste is 37.52%, and the mass percentage of CaO is 34.88%.

4. A decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas according to claim 1, characterized in that: The recycled aggregate from decoration waste is prepared by mixing 1 part of recycled aggregate from decoration waste with a particle size of 0.075 - 1.18 mm and 2 parts of recycled aggregate from decoration waste with a particle size of 1.18 - 2.36 mm.

5. A decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas according to claim 1, characterized in that: The mass percentage of SiO₂ in the silica fume is 97%.

6. The aerogel thermal insulation mortar for decoration waste with the same service life as the building structure in slightly frozen areas according to claim 1, characterized in that: The SiO₂ aerogel is a hydrophobic SiO₂ aerogel with a thermal conductivity of 0.018 W / (m·K).

7. A decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas according to claim 1, characterized in that: The silane coupling agent is KH550.

8. A decoration waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas according to claim 1, characterized in that: The water-reducing agent is a polycarboxylate superplasticizer.

9. A decorative waste aerogel thermal insulation mortar with the same service life as the building structure in slightly frozen areas according to claim 1, characterized in that: The air-entraining agent is a dodecyl sulfonate air-entraining agent.

10. A preparation method of the decoration waste aerogel thermal insulation mortar according to any one of claims 1 to 9, characterized in that: Specifically, it includes the following steps: Step S1: Soak the recycled fine aggregate from decoration waste for 6 h, and then place it in an oven at 105 °C for 3 h to dry to a saturated surface dry state. Step S2: Stir the recycled fine aggregate from decoration waste, P·O 42.5 grade cement, silica fume, air-entraining agent, water-reducing agent, and water to obtain the fresh mortar of decoration waste. Step S3: Add the silane coupling agent to the fresh mortar of decoration waste prepared in Step S2, and stir evenly to obtain the mortar of decoration waste. Step S4: Add hydrophobic SiO₂ aerogel particles to the mortar of decoration waste prepared in Step S3, and stir evenly to obtain the finished aerogel thermal insulation mortar of decoration waste.

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