Fire-resistant decoration garbage external thermal insulation mortar for exterior wall and preparation method of fire-resistant decoration garbage external thermal insulation mortar

Abstract

The invention relates to the technical field of building materials, and discloses fire-resistant decoration waste exterior wall external thermal insulation mortar and a preparation method thereof. The fire-resistant decoration waste exterior wall external thermal insulation mortar comprises the following raw material components in parts by weight: 60-410 parts of cement; 120 to 550 parts of decoration waste recycled aggregate; 36 to 75 parts of SiO2 aerogel; 8 to 17 parts of a silane coupling agent; 1.3 to 2.1 parts of dispersible latex powder; 0.5 to 1.0 part of methyl cellulose; 7-15 parts of a water reducing agent; 0.2 to 0.4 part of an air entraining agent; and 120 to 180 parts of water. According to the invention, the low-cost and high-strength decoration waste recycled aggregate is used for partially replacing expensive and low-strength aerogel, so that the thermal insulation performance of the mortar is ensured, and the material cost is greatly reduced; the decoration garbage exterior wall external thermal insulation mortar can resist high-intensity fire disasters with the highest temperature of 1000 DEG C and the fire receiving time of 2.5 h, and can be applied to exterior wall external thermal insulation systems of high-rise and super high-rise buildings with high fire extinguishing difficulty.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, in particular to a fire-resistant decoration waste exterior wall external thermal insulation mortar and a preparation method thereof. Background Art

[0002] At present, the materials used for the exterior wall insulation layer of some buildings in my country are still polyurethane foam, polystyrene foam, etc. This type of exterior wall insulation material is extremely easy to ignite, and has a fast burning speed, large heat release, rapid spread, and highly toxic combustion products.

[0003] In comparison, inorganic exterior wall insulation mortar has both insulation and fireproof functions, and has a small deformation coefficient and strong weather resistance, and is sought after by the market. It is made by mixing various lightweight aggregates with cement. Currently, most inorganic thermal insulation mortars on the market use vitrified microspheres and expanded perlite as lightweight aggregates. Although they have certain flame retardancy, their thermal insulation effect is poor, they are prone to cracking, and cannot withstand high-intensity fires. Aerogel has excellent characteristics such as high porosity (95-99.8%), super thermal insulation (0.01-0.03W / (m·K)), and high ignition point (1400℃). In recent years, it has been tried to be used in thermal insulation and fireproof mortars, but due to the ultra-light weight of aerogel (0.001-0.5g / cm 3 ), hydrophobicity and low strength characteristics, there are generally problems of uneven distribution and easy floating during preparation, and it faces the difficulties of low bonding strength of the finished product and easy peeling from the wall. The cost is extremely high and it is extremely difficult to promote and apply on a large scale.

[0004] Patent No. CN118598683A discloses an aerosol-containing lightweight flame-retardant thermal insulation mortar and its preparation method, which adds SiO2 aerogel and graphene oxide to the components, and improves the thermal insulation and crack resistance of the mortar through the synergistic interaction between graphene oxide and aerogel. However, the SiO2 aerogel is a powder with a particle size of only 30 to 100 μm, and the aerogel has not been modified, and the incompatibility problem between the aerogel and the mortar has not been solved. In addition, the components retain flammable polystyrene foam particles and polyurethane foam particles, resulting in the tensile bonding strength and fire resistance of the mortar produced not meeting the expected effect.

[0005] Patent No. CN116606100A discloses an aerogel thermal insulation fireproof mortar mixed with mineral aggregates, which improves the mechanical properties of the thermal insulation mortar by adding slag, alkali activator sodium carbonate, and cellulose ether, and achieves good results. However, the continued use of natural river sand in its components leads to poor thermal insulation performance. Moreover, the bonding strength between the mortar and the wall, which is more important for fireproof mortar, is not mentioned, and the fire resistance of the thermal insulation fireproof mortar is still questionable.

[0006] Decoration waste refers to the discarded materials generated by residential or commercial decoration, which is a mixture of bricks, stones, concrete, mortar, glass, ceramics, plastics, gypsum, etc. According to statistics, the annual output of decoration waste in my country exceeds 54.72 million tons, and the annual processing cost is as high as 21.8 billion yuan. Decoration waste has the characteristics of scattered sources, scattered quantities and high frequency of generation. In addition, its composition is very complex, which increases the difficulty of recycling. At present, the disposal methods of decoration waste in my country are mainly open-air stacking, landfill or incineration, which not only occupies a large amount of land, but also seriously damages the ecological environment. It is a difficult problem to be solved in the construction field to process decoration waste into recycled aggregates through sorting, crushing, screening and other processes to realize its resource utilization. Summary of the invention

[0007] In order to solve the problems of low fire resistance grade, easy cracking, high cost, increased discharge of decoration waste and difficulty in resource utilization of existing inorganic thermal insulation mortar, the present application proposes a fire-resistant decoration waste exterior wall insulation mortar and its preparation method.

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

[0009] A fire-resistant decoration waste exterior wall thermal insulation mortar comprises the following raw material components in parts by weight: 60-410 parts of cement; 120-550 parts of decoration waste recycled aggregate; 36-75 parts of SiO2 aerogel; 8-17 parts of silane coupling agent; 1.3-2.1 parts of dispersible latex powder; 0.5-1.0 part of methyl cellulose; 7-15 parts of water reducer; 0.2-0.4 part of air entraining agent; and 120-180 parts of water.

[0010] Furthermore, the SiO2 aerogel has a particle size of 0.1 to 2.36 mm and a specific surface area of ​​500 to 1000 m 2 / g, porosity>90%, thermal conductivity of 0.01 ~ 0.03W / (m·K).

[0011] Furthermore, the apparent density of the decoration waste recycled aggregate is 1900-2300 kg / m 3 , particle size range <4.75mm.

[0012] Furthermore, the cement is po 42.5 ordinary silicate cement; the silane coupling agent is KH550 silane coupling agent; the bulk density of the dispersible latex powder is 450-500 kg / m 3 , the average particle size is 90-95 μm; the water retention rate of the methyl cellulose is not less than 98%, and the viscosity is 150000-250000 mPa·s; the water reducer is a polycarboxylic acid water reducer, and the water reduction efficiency is not less than 25%; the air entraining agent is sodium dodecyl sulfate, the chemical formula is C 12 H 25SO4Na, active matter content not less than 95%.

[0013] A method for preparing the fire-resistant decoration waste exterior wall thermal insulation mortar as described above specifically comprises the following steps:

[0014] Step S1, soaking the decoration waste recycled aggregate in water until it is saturated and surface dry, and then taking it out;

[0015] Step S2, preparing a silane coupling agent solution with a concentration of 5 wt%, adding SiO2 aerogel into the silane coupling agent solution, stirring and then taking out to obtain modified SiO2 aerogel;

[0016] Step S3, adding cement, dispersible latex powder, methyl cellulose, recycled aggregate from renovation waste, and modified SiO2 aerogel into a mixer in sequence, and stirring until the renovation waste and aerogel particles are evenly dispersed to obtain a mixture;

[0017] Step S4, adding a water reducing agent, an air entraining agent and water to the mixture obtained in step S3, stirring evenly for 3 minutes, and then putting it into a mold and tamping it to obtain a test block;

[0018] Step S5, the test block obtained in step S4 is demoulded after curing at room temperature for 48 hours, and moved into a curing room for curing for 28 days to obtain a finished product of decoration waste exterior wall external insulation mortar.

[0019] Furthermore, in step S2, the stirring speed is 400-600 rpm, and the stirring time is 3-5 min.

[0020] Furthermore, in step S5, the temperature of the curing room is 23±2° C. and the relative humidity is 50±5%.

[0021] The beneficial effects of the present invention are as follows: the present invention has a reasonable design, a simple preparation method, and has the following advantages:

[0022] (1) In the fire-resistant decoration waste exterior wall insulation mortar of the present invention, the decoration waste recycled aggregate contains bricks, mortar, plastic, gypsum and other components, and has the typical characteristics of light aggregate (such as low density). The present invention abandons the high-density river sand in the traditional insulation mortar components and adopts low-cost, high-strength decoration waste recycled aggregate to partially replace the expensive, low-strength aerogel. Through the adjustment and optimization of the components, while ensuring the thermal insulation performance of the mortar, the material cost is greatly reduced, and the self-strength of the mortar, the bonding strength with the wall and the fire resistance performance are significantly improved; at the same time, the decoration waste is efficiently utilized as a renewable resource to promote the green, low-carbon and circular development of the construction industry;

[0023] (2) The preparation method of the present invention uses a silane coupling agent to pretreat the aerogel. The silane coupling agent provides amino groups (-NH2) that can chemically bond with the siloxy groups (-Si-OH) on the surface of the aerogel particles to form strong covalent bonds. The introduced hydroxyl groups (-OH) interact with water molecules through hydrogen bonds, thereby reducing the contact angle of the aerogel surface, improving the interface compatibility between the aerogel and the mortar, and effectively solving the problem of easy floating and uneven distribution of aerogel particles in the mortar system. When the aerogel particles are evenly distributed in the mortar system, on the one hand, the uniform and dense nanopores and multi-level fractal pore structures formed can effectively reduce thermal radiation and heat conduction, and improve the fire resistance of the mortar; on the other hand, it prevents the problem of too low bonding strength in some areas caused by the accumulation of aerogel particles.

[0024] (3) The fire-resistant decoration waste exterior wall insulation mortar of the present invention is mixed with dispersible latex powder and methyl cellulose, wherein the dispersible latex powder forms a flexible polymer film during the evaporation of water in the mortar, and the methyl cellulose improves the viscosity of the mortar during the hydration process through hydrogen bond interaction with water molecules. Within a reasonable dosage range, the mixed mixture of the two improves the consistency and water retention of the mortar, and gives the mortar matrix good viscosity, toughness and crack resistance. At the same time, it can also optimize the dispersion of aerogel in the mortar, and achieve a synergistic effect with the aerogel pretreatment, thereby greatly improving the bonding strength and fire resistance of the exterior wall insulation mortar itself and between it and the exterior wall;

[0025] (4) The fire-resistant decoration waste exterior wall insulation mortar of the present invention can greatly improve its own strength, bonding strength with the wall and fire resistance by pre-modifying the aerogel and adjusting and optimizing the components, and compounding with dispersible latex powder and methyl cellulose. Compared with conventional insulation mortar, the decoration waste exterior wall insulation mortar of the present invention can withstand high-intensity fires with a maximum temperature of 1000°C and a fire exposure time of 2.5 hours. After the fire, the bonding strength with the wall still meets the regulatory requirements, ensuring that it does not fall off after being exposed to a high-intensity fire. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the bonding strength loss and mass loss of the thermal insulation mortars of Examples 1 to 5 and Comparative Examples 1 to 3 after being exposed to fire. DETAILED DESCRIPTION

[0028] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0029] 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 description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0030] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] A fire-resistant decoration waste exterior wall thermal insulation mortar comprises the following raw material components in parts by weight: 60-410 parts of cement; 120-550 parts of decoration waste recycled aggregate; 36-75 parts of SiO2 aerogel; 8-17 parts of silane coupling agent; 1.3-2.1 parts of dispersible latex powder; 0.5-1.0 part of methyl cellulose; 7-15 parts of water reducer; 0.2-0.4 part of air entraining agent; and 120-180 parts of water.

[0032] The particle size of SiO2 aerogel is 0.1~2.36mm, and the specific surface area is 500~1000m 2 / g, porosity>90%, thermal conductivity of 0.01 ~ 0.03W / (m·K).

[0033] The apparent density of recycled aggregate from renovation waste is 1900~2300kg / m 3 , particle size range <4.75mm.

[0034] The cement is po 42.5 ordinary silicate cement; the silane coupling agent is KH550 silane coupling agent; the bulk density of the dispersible latex powder is 450-500kg / m 3 , the average particle size is 90-95μm; the water retention rate of methyl cellulose is not less than 98%, and the viscosity is 150000-250000mPa·s; the water reducer is a polycarboxylic acid water reducer, and the water reduction efficiency is not less than 25%; the air entraining agent is sodium dodecyl sulfate, and the chemical formula is C 12 H 25SO4Na, the active matter content is not less than 95%. The function of the air entraining agent is to introduce a large number of evenly distributed, closed and stable tiny bubbles into the mortar to improve the thermal insulation performance.

[0035] A method for preparing the fire-resistant decoration waste exterior wall thermal insulation mortar as described above specifically comprises the following steps:

[0036] Step S1, soaking the decoration waste recycled aggregate in water until it is saturated and surface dry, and then taking it out;

[0037] Step S2, preparing a silane coupling agent solution with a concentration of 5 wt%, adding SiO2 aerogel into the silane coupling agent solution, stirring and then taking out to obtain modified SiO2 aerogel;

[0038] Step S3, adding cement, dispersible latex powder, methyl cellulose, recycled aggregate from renovation waste, and modified SiO2 aerogel into a mixer in sequence, and stirring until the renovation waste and aerogel particles are evenly dispersed to obtain a mixture;

[0039] Step S4, adding a water reducing agent, an air entraining agent and water to the mixture obtained in step S3, stirring evenly for 3 minutes, and then putting it into a mold and tamping it to obtain a test block;

[0040] Step S5, the test block obtained in step S4 is demoulded after curing at room temperature for 48 hours, and moved into a curing room for curing for 28 days to obtain a finished product of decoration waste exterior wall external insulation mortar.

[0041] In step S2, the rotation speed during stirring is 400-600 rpm, and the stirring time is 3-5 min.

[0042] In step S5, the temperature of the curing room is 23±2°C and the relative humidity is 50±5%.

[0043] Example 1

[0044] A fire-resistant decoration waste exterior wall thermal insulation mortar comprises the following raw material components in parts by weight: 336 parts of cement; 151 parts of decoration waste recycled aggregate; 60 parts of SiO2 aerogel; 12 parts of silane coupling agent; 1.7 parts of dispersible latex powder; 0.7 parts of methyl cellulose; 11 parts of water reducer; 0.3 parts of air entraining agent; and 150 parts of water.

[0045] The method for preparing the above-mentioned fire-resistant decoration waste exterior wall external insulation mortar specifically comprises the following steps:

[0046] Step S1, soaking the decoration waste recycled aggregate in water for 30 minutes until it reaches a saturated surface dry state and then fishing it out;

[0047] Step S2, preparing a silane coupling agent solution with a concentration of 5wt%, adding SiO2 aerogel into the silane coupling agent solution, stirring and then taking it out, the stirring speed is 400-600rpm, and the stirring time is 3-5min, to obtain modified SiO2 aerogel;

[0048] Step S3, adding cement, dispersible latex powder, methyl cellulose, decoration waste recycled aggregate, and modified SiO2 aerogel into a mixer in sequence, stirring for 1 minute until the decoration waste and aerogel particles are evenly dispersed, to obtain a mixture;

[0049] Step S4, adding a water reducing agent, an air entraining agent and water to the mixture obtained in step S3, stirring evenly for 3 minutes, and then putting it into a mold and tamping it to obtain a test block;

[0050] Step S5, curing the test block obtained in step S4 at room temperature for 48 hours, then demoulding, moving it into a standard curing room (temperature 23±2°C, relative humidity 50±5%) and curing it for 28 days to obtain a finished product of decoration waste exterior wall external insulation mortar.

[0051] Example 2

[0052] Different from Example 1, the formula of the fire-resistant decoration waste exterior wall insulation mortar in this embodiment is as follows:

[0053] 336 parts of cement; 227 parts of recycled aggregate from renovation waste; 56 parts of SiO2 aerogel; 11 parts of silane coupling agent; 1.7 parts of dispersible latex powder; 0.7 parts of methyl cellulose; 11 parts of water reducer; 0.3 parts of air entraining agent; 150 parts of water.

[0054] The other operation steps are the same as those in Example 1.

[0055] Example 3

[0056] Different from Example 1, the formula of the fire-resistant decoration waste exterior wall insulation mortar in this embodiment is as follows:

[0057] 336 parts of cement; 303 parts of recycled aggregate from renovation waste; 53 parts of SiO2 aerogel; 11 parts of silane coupling agent; 1.7 parts of dispersible latex powder; 0.7 parts of methyl cellulose; 11 parts of water reducer; 0.3 parts of air entraining agent; 150 parts of water.

[0058] The other operation steps are the same as those in Example 1.

[0059] Example 4

[0060] Different from Example 1, the formula of the fire-resistant decoration waste exterior wall insulation mortar in this embodiment is as follows:

[0061] 336 parts of cement; 378 parts of recycled aggregate from renovation waste; 50 parts of SiO2 aerogel; 10 parts of silane coupling agent; 1.7 parts of dispersible latex powder; 0.7 parts of methyl cellulose; 11 parts of water reducer; 0.3 parts of air entraining agent; 150 parts of water.

[0062] The other operation steps are the same as those in Example 1.

[0063] Example 5

[0064] Different from Example 1, the formula of the fire-resistant decoration waste exterior wall insulation mortar in this embodiment is as follows:

[0065] 336 parts of cement; 454 parts of recycled aggregate from renovation waste; 46 parts of SiO2 aerogel; 9 parts of silane coupling agent; 1.7 parts of dispersible latex powder; 0.7 parts of methyl cellulose; 11 parts of water reducer; 0.3 parts of air entraining agent; 150 parts of water.

[0066] The other operation steps are the same as those in Example 1.

[0067] Comparative Example 1

[0068] Different from Example 1, the formula of the thermal insulation mortar in this comparative example is as follows:

[0069] 336 parts of cement; 66 parts of SiO2 aerogel; 13 parts of silane coupling agent; 1.7 parts of dispersible latex powder; 0.7 parts of methyl cellulose; 11 parts of water reducer; 0.3 parts of air entraining agent; 150 parts of water.

[0070] The preparation method of the thermal insulation mortar in this comparative example is as follows:

[0071] (1) Prepare a 5% silane coupling agent solution, add SiO2 aerogel into the silane coupling agent solution, stir and remove, the stirring speed is 400-600 rpm, the stirring time is 3-5 min, and the modified SiO2 aerogel is obtained.

[0072] (2) Add cement, dispersible latex powder, methyl cellulose, and modified SiO2 aerogel into the mixer in sequence, and stir for 1 min until the aerogel particles are evenly dispersed;

[0073] (3) Add water reducing agent, air entraining agent and water, stir evenly for 3 minutes, then put into the mold and tamp;

[0074] (4) After curing the test block at room temperature for 48 hours, demould it and move it into a standard curing room (temperature 23±2°C, relative humidity 50±5%) for curing for 28 days to obtain the thermal insulation mortar.

[0075] Comparative Example 2

[0076] Different from Example 1, the formula of the thermal insulation mortar in this comparative example is as follows:

[0077] 336 parts of cement; 605 parts of recycled aggregate from renovation waste; 40 parts of SiO2 aerogel; 8 parts of silane coupling agent; 1.7 parts of dispersible latex powder; 0.7 parts of methyl cellulose; 11 parts of water reducer; 0.3 parts of air entraining agent; 150 parts of water.

[0078] The other operation steps are the same as those in Example 1.

[0079] Comparative Example 3

[0080] Different from Example 1, the formula of the thermal insulation mortar in this comparative example is as follows:

[0081] 336 parts of cement; 303 parts of recycled aggregate from renovation waste; 53 parts of SiO2 aerogel; 11 parts of water reducing agent; 0.3 parts of air entraining agent; 150 parts of water.

[0082] The preparation method of the thermal insulation mortar in this comparative example is as follows:

[0083] (1) Add cement, recycled aggregate from renovation waste, and SiO2 aerogel into a mixer in sequence and stir for 1 minute;

[0084] (2) Add water reducing agent, air entraining agent and water, stir evenly for 3 minutes, then put into the mold and tamp;

[0085] (3) After curing the test block at room temperature for 48 hours, demould it and move it into a standard curing room (temperature 23±2°C, relative humidity 50±5%) for curing for 28 days to obtain the thermal insulation mortar.

[0086] Performance testing method:

[0087] The thermal conductivity of the insulation mortar was determined with reference to the standard GBT10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Insulating Materials - Protected Hot Plate Method". The bonding strength between the insulation mortar and the exterior wall substrate was determined with reference to the standard GBT20473-2021 "Building Insulation Mortar". The fire history was simulated with reference to the building fire heating curve in the standard GBT9978.1-2008 "Fire Resistance Test Method for Building Components", the fire intensity (maximum temperature) was set to 1000°C, the fire time was 2.5h, and the mass loss and bonding strength loss of the insulation mortar after fire were determined with reference to the standard GBT20473-2021 "Building Insulation Mortar".

[0088] The performance test results of Examples 1 to 5 and Comparative Examples 1 to 3 are shown in Tables 1 and Figure 1 shown.

[0089] Table 1 Performance test results of Examples 1 to 5 and Comparative Examples 1 to 3

[0090]

[0091] By comparing Examples 1 to 5 and Comparative Examples 1 to 2 in Table 1, it can be found that the thermal insulation mortar without recycled aggregate from decoration waste (Comparative Example 1) has the best thermal insulation effect, but its bonding strength with the exterior wall matrix is ​​also the lowest. After being exposed to a fire at 1000°C for 2.5 hours, cracking was obvious, and the bonding strength with the exterior wall matrix was only 48KPa, which did not reach the bonding strength of 60KPa specified in GBT20473-2021 "Building Thermal Insulation Mortar", and the mass loss after the fire was also higher than that of Examples 1 to 5. With the increase in the amount of recycled aggregate from decoration waste (Examples 1 to 5), the thermal conductivity of the mortar gradually increased, but it was still less than 0.08W / (m·K) specified in the specification. Under the premise of slightly sacrificing thermal insulation performance, the bonding strength and fire resistance with the exterior wall matrix were significantly improved: the loss of bonding strength and mass loss after the fire were reduced. However, when the recycled aggregate from renovation waste is added up to 40% (Comparative Examples 2 and 3), the thermal insulation performance loss is too large (thermal conductivity coefficient>0.08W / (m·K)), and due to the low content of aerogel, the fire resistance is also the worst.

[0092] By comparing Examples 1 to 5 and Comparative Example 3 in Table 1, it can be found that when the aerogel is pretreated with a silane coupling agent in the preparation method and the dispersible latex powder and methyl cellulose are not added to the components, the thermal conductivity of the mortar is the highest, the bonding strength with the exterior wall substrate is the lowest, and the thermal insulation performance and strength are much weaker than those of Example 3 with the same aerogel dosage. Moreover, the mass loss after the fire is as high as 17.7%, and the thermal insulation mortar falls off from the exterior wall substrate and no longer has 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 thermal insulation mortar for the exterior wall of the decoration waste has good thermal insulation performance and bonding strength, and can withstand high-temperature fires. The bonding strength loss and mass loss after the fire are lower than those of Comparative Examples 1 to 3.

[0093] From Table 1 and Figure 1 It can be seen that the overall performance of Examples 2 to 4 is better, that is, when the amount of decoration waste is 15% to 25%, the bonding strength loss and mass loss after fire can be as low as 88.3% and 9.7%, which not only ensures better thermal insulation performance, but also maximizes the bonding strength and fire resistance of the thermal insulation mortar, avoiding the technical defects caused by too little / excessive addition of aerogel.

[0094] In summary, the present invention has a reasonable design, a simple preparation method and the following advantages:

[0095] (1) In the fire-resistant decoration waste exterior wall insulation mortar of the present invention, the decoration waste recycled aggregate contains bricks, mortar, plastic, gypsum and other components, and has the typical characteristics of light aggregate (such as low density). The present invention abandons the high-density river sand in the traditional insulation mortar components and adopts low-cost, high-strength decoration waste recycled aggregate to partially replace the expensive, low-strength aerogel. Through the adjustment and optimization of the components, while ensuring the thermal insulation performance of the mortar, the material cost is greatly reduced, and the self-strength of the mortar, the bonding strength with the wall and the fire resistance performance are significantly improved; at the same time, the decoration waste is efficiently utilized as a renewable resource to promote the green, low-carbon and circular development of the construction industry;

[0096] (2) The preparation method of the present invention uses a silane coupling agent to pretreat the aerogel. The silane coupling agent provides amino groups (-NH2) that can chemically bond with the siloxy groups (-Si-OH) on the surface of the aerogel particles to form strong covalent bonds. The introduced hydroxyl groups (-OH) interact with water molecules through hydrogen bonds, thereby reducing the contact angle of the aerogel surface, improving the interface compatibility between the aerogel and the mortar, and effectively solving the problem of easy floating and uneven distribution of aerogel particles in the mortar system. When the aerogel particles are evenly distributed in the mortar system, on the one hand, the uniform and dense nanopores and multi-level fractal pore structures formed can effectively reduce thermal radiation and heat conduction, and improve the fire resistance of the mortar; on the other hand, it prevents the problem of too low bonding strength in some areas caused by the accumulation of aerogel particles.

[0097] (3) The fire-resistant decoration waste exterior wall insulation mortar of the present invention is mixed with dispersible latex powder and methyl cellulose, wherein the dispersible latex powder forms a flexible polymer film during the evaporation of water in the mortar, and the methyl cellulose improves the viscosity of the mortar during the hydration process through hydrogen bond interaction with water molecules. Within a reasonable dosage range, the mixed mixture of the two improves the consistency and water retention of the mortar, and gives the mortar matrix good viscosity, toughness and crack resistance. At the same time, it can also optimize the dispersion of aerogel in the mortar, and achieve a synergistic effect with the aerogel pretreatment, thereby greatly improving the bonding strength and fire resistance of the exterior wall insulation mortar itself and between it and the exterior wall;

[0098] (4) The fire-resistant decoration waste exterior wall insulation mortar of the present invention can greatly improve its own strength, bonding strength with the wall and fire resistance by pre-modifying the aerogel and adjusting and optimizing the components, and compounding with dispersible latex powder and methyl cellulose. Compared with conventional insulation mortar, the decoration waste exterior wall insulation mortar of the present invention can withstand high-intensity fires with a maximum temperature of 1000°C and a fire exposure time of 2.5 hours. After the fire, the bonding strength with the wall still meets the regulatory requirements, ensuring that it does not fall off after being exposed to a high-intensity fire.

[0099] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, 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 fire-resistant decoration waste exterior wall insulation mortar, characterized by: The thermal insulation mortar comprises the following raw material components in parts by weight: 60-410 parts of cement; 120-550 parts of recycled aggregate from renovation waste; 36-75 parts of SiO2 aerogel; 8-17 parts of silane coupling agent; 1.3-2.1 parts of dispersible latex powder; 0.5-1.0 parts of methyl cellulose; 7-15 parts of water reducing agent; 0.2-0.4 parts of air entraining agent; 120-180 parts of water.

2. The fire-resistant decoration waste exterior wall insulation mortar according to claim 1, characterized in that: The SiO2 aerogel has a particle size of 0.1 to 2.36 mm and a specific surface area of ​​500 to 1000 m 2 / g, porosity>90%, thermal conductivity of 0.01 ~ 0.03W / (m·K).

3. The fire-resistant decoration waste exterior wall insulation mortar according to claim 1, characterized in that: The apparent density of the decoration waste recycled aggregate is 1900-2300 kg / m 3 , particle size range <4.75mm.

4. The fire-resistant decoration waste exterior wall insulation mortar according to claim 1, characterized in that: The cement is po 42.5 ordinary silicate cement; the silane coupling agent is KH550 silane coupling agent; the bulk density of the dispersible latex powder is 450-500 kg / m 3 , the average particle size is 90-95 μm; the water retention rate of the methyl cellulose is not less than 98%, and the viscosity is 150000-250000 mPa·s; the water reducer is a polycarboxylic acid water reducer, and the water reduction efficiency is not less than 25%; the air entraining agent is sodium dodecyl sulfate, and the active matter content is not less than 95%.

5. A method for preparing the fire-resistant decoration waste exterior wall insulation mortar according to any one of claims 1 to 4, characterized in that: The specific steps include: Step S1, soaking the decoration waste recycled aggregate in water until it is saturated and surface dry, and then taking it out; Step S2, preparing a silane coupling agent solution with a concentration of 5 wt%, adding SiO2 aerogel into the silane coupling agent solution, stirring and then taking out to obtain modified SiO2 aerogel; Step S3, adding cement, dispersible latex powder, methyl cellulose, recycled aggregate from renovation waste, and modified SiO2 aerogel into a mixer in sequence, and stirring until the renovation waste and aerogel particles are evenly dispersed to obtain a mixture; Step S4, adding a water reducing agent, an air entraining agent and water to the mixture obtained in step S3, stirring evenly for 3 minutes, and then putting it into a mold and tamping it to obtain a test block; Step S5, the test block obtained in step S4 is demoulded after curing at room temperature for 48 hours, and moved into a curing room for curing for 28 days to obtain a finished product of decoration waste exterior wall external insulation mortar.

6. The method for preparing a fire-resistant decoration waste exterior wall thermal insulation mortar according to claim 5, characterized in that: In step S2, the stirring speed is 400-600 rpm and the stirring time is 3-5 min.

7. The method for preparing a fire-resistant decoration waste exterior wall thermal insulation mortar according to claim 5, characterized in that: In step S5, the temperature of the curing room is 23±2° C. and the relative humidity is 50±5%.

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