Thermal insulation mortar and preparation method thereof
By introducing cement, fly ash and other components into the thermal insulation mortar and using polyacrylamide to graft basalt fiber and palygorskite fiber to cross-link to form an inorganic-organic network structure, the problems of brittleness and easy cracking of glass bead thermal insulation mortar were solved, and a high-strength and crack-resistant thermal insulation mortar was achieved.
Patent Information
- Application Number
- CN202310995163.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-09
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2043-08-09
AI Technical Summary
The existing inorganic thermal insulation mortar, the vitrified microbead thermal insulation mortar, is brittle, has large shrinkage, is prone to hollowing and cracking, and has poor crack resistance.
Cement, fly ash, redispersible latex powder, glass beads, microsilica powder, palygorskite fiber, polyacrylamide grafted basalt fiber and other components are used to form an inorganic fiber network structure, and the polyacrylamide grafted basalt fiber and palygorskite fiber are cross-linked to form an organic network structure to improve crack resistance.
It significantly improves the strength and crack resistance of the thermal insulation mortar, enhances the flexibility and bonding strength, and improves the grading and flame retardant properties of the vitrified microspheres.
Smart Images
Figure BDA0004384309630000081
Abstract
Description
Technical Field
[0001] The present application relates to the field of thermal insulation mortar, and more specifically, to a thermal insulation mortar and a preparation method thereof. Background Art
[0002] Insulation mortars mainly include organic rubber powder-based insulation mortars and inorganic insulation mortars. Organic insulation mortars are less expensive, but have poor fire resistance and relatively high environmental pollution, so they are less commonly used. Inorganic insulation mortars offer excellent thermal insulation, fire resistance, and aging resistance, and are easy to apply.
[0003] Inorganic thermal insulation mortars primarily use gypsum or cement as the binder, inorganic vitrified microspheres as lightweight aggregate, and anti-cracking additives and other fillers to create a dry-mix mortar. However, most vitrified microsphere insulation mortars are brittle, shrink rapidly, and are prone to hollowing and cracking, resulting in poor crack resistance.
[0004] In response to the above-mentioned related technologies, the present application provides a thermal insulation mortar with high strength, good toughness and excellent crack resistance. Summary of the Invention
[0005] In order to improve the crack resistance of thermal insulation mortar, the present application provides a thermal insulation mortar and a preparation method thereof.
[0006] In the first aspect, the present application provides a thermal insulation mortar, which adopts the following technical solution:
[0007] A thermal insulation mortar comprising the following components in parts by weight:
[0008] 40-50 parts of cement,
[0009] 30-45 parts fly ash,
[0010] 8-15 parts of redispersible latex powder,
[0011] 30-45 parts of vitrified microspheres,
[0012] 10-25 parts of microsilica powder,
[0013] 6-10 parts of palygorskite fiber,
[0014] 8-15 parts of polyacrylamide grafted basalt fiber,
[0015] 2-5 parts of cellulose ether,
[0016] 5-8 parts of water reducing agent,
[0017] 2-5 parts of retarder;
[0018] The palygorskite fiber is stearic acid modified palygorskite fiber.
[0019] By adopting the above technical solution, cement, fly ash and redispersible latex powder are used as the cementitious materials of the thermal insulation mortar. Fly ash can improve the workability of the mortar, reduce the amount of cement used and reduce the cost of the thermal insulation mortar. The redispersible latex powder has high bonding strength, which helps to improve the adhesion of the thermal insulation mortar and can form a flexible polymer film composite system between inorganic materials, thereby improving the cohesion of the thermal insulation mortar and helping to improve the flexural strength, water retention, flexibility and crack resistance of the mortar. Glass microspheres and microsilica powder are used as aggregates. Glass microspheres have excellent thermal insulation and fireproofing properties. Microsilica powder helps to make the aggregate have better gradation and improve the flame retardant and crack resistance. Cellulose ether has thickening, water retention and thixotropy, which can improve the wet viscosity of the thermal insulation mortar. The water reducer is conducive to improving the mixing effect of the thermal insulation mortar and improving the dispersion performance of cement and inorganic aggregate. The retarder helps to adjust the setting time of the cement.
[0020] Polyacrylamide-grafted basalt fiber and palygorskite fiber are used as anti-cracking fibers. The polyacrylamide-grafted basalt fiber and palygorskite fiber are dispersed in the thermal insulation mortar to form an inorganic fiber network structure. The polyacrylamide-grafted basalt fiber has the advantages of high strength, good flame retardancy, high compression strength and shear strength, and good bonding with the cementitious material. The palygorskite fiber, i.e., fibrous palygorskite, has high flame retardancy, good viscosity and plasticity, and the shrinkage deformation of the palygorskite fiber and the polyacrylamide-grafted basalt fiber is small. The inorganic network structure formed by the combination of the two can significantly improve the strength and crack resistance of the thermal insulation mortar.
[0021] The polyacrylamide on the surface of the polyacrylamide-grafted basalt fiber can cross-link with the polymer film formed by the redispersible latex powder and the stearic acid molecules on the surface of the palygorskite fiber, forming an organic network structure on the basis of the inorganic fiber network, further improving the flexibility and crack resistance of the thermal insulation mortar.
[0022] Preferably, the preparation method of the polyacrylamide grafted basalt fiber comprises the following steps:
[0023] Adding a silane coupling agent to an ethanol solution to prepare a 5-10 wt% coupling agent solution, adjusting the pH value to 4-5, immersing the basalt fiber in the solution, dispersing the basalt fiber uniformly, immersing the solution for 20-40 minutes, filtering, washing, and drying to obtain a coupled modified basalt fiber;
[0024] The coupled modified basalt fiber is ultrasonically dispersed in water, heated to 80-100°C under a nitrogen atmosphere, and ammonium persulfate is added thereto while stirring, followed by acrylamide. After stirring for 6-9 hours, the mixture is filtered, washed, and dried to obtain polyacrylamide-grafted modified basalt fiber.
[0025] By adopting the above technical solution, the silane coupling agent can react physically or chemically with the surface of the basalt fiber and be grafted onto the surface of the basalt fiber. Acrylamide undergoes polymerization reaction under the initiation of ammonium persulfate and combines with the coupling agent molecules on the surface of the basalt fiber, and is indirectly grafted onto the basalt fiber through the coupling agent molecules.
[0026] The grafting of polyacrylamide onto basalt fiber increases the surface roughness and adhesion of basalt fiber, and improves the bonding strength between basalt fiber and cementitious materials such as cement; polyacrylamide molecules can cross-link with the polymer film formed by redispersible latex powder and the stearic acid molecules on the surface of palygorskite fiber, promoting the formation of an organic network structure in the thermal insulation mortar, which is beneficial to improving the crack resistance of the thermal insulation mortar.
[0027] Preferably, the preparation method of the polyacrylamide grafted basalt fiber further comprises the following steps:
[0028] Under ultrasonic conditions, the basalt fiber is immersed in a 0.8-1.2 mol / L hydrochloric acid solution for 2-4 hours, filtered out, washed to neutrality, and dried to obtain the pretreated basalt fiber;
[0029] The pretreated basalt fiber is then treated with a silane coupling agent to obtain a coupled modified basalt fiber; and the coupled modified basalt fiber is treated with ammonium persulfate and acrylamide under a nitrogen atmosphere to obtain a polyacrylamide-grafted modified basalt fiber.
[0030] By adopting the above technical solution, acid etching treatment can form grooves on the surface of basalt fiber, increase the surface roughness and specific surface area of basalt fiber, further improve the bonding strength between basalt fiber and cementitious material; and form more abundant active groups on the surface of basalt fiber, increase the grafting rate of coupling agent molecules, and thus help to increase the grafting rate of polyacrylamide.
[0031] Preferably, the mass ratio of the acrylamide to the coupled modified basalt fiber is (0.1-0.6):1; the mass of the ammonium persulfate is 1-3% of the mass of the acrylamide.
[0032] Preferably, the length of the basalt fiber is 4-8 mm.
[0033] By adopting the above technical solution, the possibility of excessive curling of the polyacrylamide grafted basalt fiber caused by excessive polyacrylamide loading and wrapping the basalt fiber, or excessive length of the basalt fiber, which affects the crack resistance and strength of the insulating sand and gravel, is reduced.
[0034] Preferably, the preparation method of the stearic acid modified palygorskite fiber comprises:
[0035] Stearic acid and palygorskite fiber are mixed and added into water, heated to 90-120° C., stirred for 10-30 minutes, filtered, and dried to obtain stearic acid-modified palygorskite fiber;
[0036] The mass of the stearic acid is 10-50% of the palygorskite fiber.
[0037] By adopting the above technical solution, stearic acid is an anionic surfactant, and one end of the stearic acid molecule can physically or chemically react with the surface of the palygorskite fiber to modify the surface of the palygorskite fiber and improve the dispersion performance of the palygorskite fiber; the other end of the stearic acid molecule can cross-link with the polymer system formed by the redispersible latex powder or the polyacrylamide grafted basalt fiber, promote the formation of an organic network structure and an inorganic fiber network, and further improve the crack resistance of the thermal insulation mortar.
[0038] Preferably, the length of the palygorskite fiber is 0.2-2 μm.
[0039] Preferably, the water reducer is a melamine high-efficiency water reducer.
[0040] Preferably, the retarder is a combination of one or more of calcium gluconate, sodium citrate, calcium citrate, calcium superphosphate, zinc sulfate, and sodium lignosulfonate.
[0041] In a second aspect, the present application provides a method for preparing thermal insulation mortar, which adopts the following technical solution:
[0042] A method for preparing thermal insulation mortar comprises the following steps:
[0043] According to the proportion, cement, fly ash, redispersible latex powder, palygorskite fiber, polyacrylamide grafted basalt fiber, cellulose ether, water reducer and retarder are stirred and mixed for 3-5 minutes, and then glass beads and microsilica powder are added and stirred for 1-2 minutes to obtain thermal insulation mortar.
[0044] By adopting the above technical solution, a dry powder thermal insulation mortar with high strength, good water retention and excellent crack resistance can be obtained.
[0045] In summary, this application has the following beneficial effects:
[0046] 1. Since this application uses polyacrylamide-grafted basalt fiber and palygorskite fiber as anti-cracking fibers, the polyacrylamide-grafted basalt fiber and palygorskite fiber are dispersed in the thermal insulation mortar to form an inorganic fiber network structure, which significantly improves the strength and crack resistance of the thermal insulation mortar; the polyacrylamide on the surface of the polyacrylamide-grafted basalt fiber can cross-link with the polymer film formed by the redispersible latex powder and the stearic acid molecules on the surface of the palygorskite fiber, forming an organic network structure on the basis of the inorganic fiber network, further improving the flexibility and crack resistance of the thermal insulation mortar;
[0047] 2. In the present application, the grafting of polyacrylamide onto basalt fiber increases the surface roughness and adhesion of the basalt fiber, improves the bonding strength between the basalt fiber and cement and other cementitious materials, and is beneficial to improving the crack resistance of the thermal insulation mortar; 3. In the present application, the basalt fiber is preferably subjected to acid etching pretreatment. The acid etching treatment can form grooves on the surface of the basalt fiber, increase the surface roughness and specific surface area of the basalt fiber, and further improve the bonding strength between the basalt fiber and the cementitious material; and form more abundant active groups on the surface of the basalt fiber, thereby increasing the grafting rate of the coupling agent molecules, which is beneficial to increasing the grafting rate of polyacrylamide. DETAILED DESCRIPTION
[0048] The present application is further described in detail below with reference to the embodiments.
[0049] Preparation Example
[0050] Preparation Example 1
[0051] This preparation example provides a polyacrylamide grafted basalt fiber, and the preparation method includes the following steps:
[0052] The silane coupling agent was added to a 95% ethanol solution to prepare a 5 wt% coupling agent solution, and citric acid was added dropwise to adjust the pH value to 4-5;
[0053] Basalt fiber was immersed in it according to a bath ratio of 1:10, ultrasonically dispersed evenly, immersed for 30 minutes, filtered out, washed three times, and dried at 100°C to obtain coupled modified basalt fiber;
[0054] The coupled modified basalt fiber was ultrasonically dispersed in water, heated to 80°C under a nitrogen atmosphere, and ammonium persulfate was added thereto while stirring, and then acrylamide was slowly added thereto. After stirring for 7 hours, it was filtered, washed three times, and dried at 100°C to obtain modified basalt fiber grafted with polyacrylamide.
[0055] In this preparation example, the mass ratio of acrylamide to coupled modified basalt fiber is 0.1:1; the mass of ammonium persulfate is 2% of the mass of acrylamide.
[0056] In this preparation example, the length of the basalt fibers ranges from 4 to 8 mm.
[0057] Preparation Example 2
[0058] The only difference between this preparation example and Preparation Example 1 is that the mass ratio of acrylamide to coupled modified basalt fiber is 0.4:1.
[0059] Preparation Example 3
[0060] The only difference between this preparation example and Preparation Example 1 is that the mass ratio of acrylamide to coupled modified basalt fiber is 0.6:1.
[0061] Preparation Example 4
[0062] The only difference between this preparation example and Preparation Example 1 is that the mass ratio of acrylamide to coupled modified basalt fiber is 0.8:1.
[0063] Preparation Example 5
[0064] The only difference between this preparation example and Preparation Example 1 is that the length of the basalt fiber ranges from 8 to 15 mm.
[0065] Preparation Example 6
[0066] The only difference between this preparation example and preparation example 1 is that the preparation method of polyacrylamide grafted basalt fiber includes the following steps: immersing the basalt fiber in a 0.8 mol / L hydrochloric acid solution under ultrasonic conditions for 3 hours, filtering out, washing to neutrality, and drying to obtain pretreated basalt fiber;
[0067] The silane coupling agent was added to a 95% ethanol solution to prepare a 5 wt% coupling agent solution, and citric acid was added dropwise to adjust the pH value to 4-5; the pretreated basalt fiber was immersed in the solution at a bath ratio of 1:10, ultrasonically dispersed uniformly, immersed for 30 minutes, filtered, washed three times, and dried at 100°C to obtain a coupled modified basalt fiber;
[0068] The coupled modified basalt fiber was ultrasonically dispersed in water, heated to 80°C under a nitrogen atmosphere, and ammonium persulfate was added thereto while stirring, and then acrylamide was slowly added thereto. After stirring for 7 hours, it was filtered, washed three times, and dried at 100°C to obtain modified basalt fiber grafted with polyacrylamide.
[0069] Preparation Example 7
[0070] The only difference between this Preparation Example and Preparation Example 7 is that the concentration of the hydrochloric acid solution is 1.2 mol / L.
[0071] Preparation Example 8
[0072] This preparation example provides a modified palygorskite fiber, and the preparation method includes the following steps:
[0073] Stearic acid and palygorskite fiber are mixed and added into water, wherein the mass of stearic acid is 10% of the palygorskite fiber; the mixture is heated to 100° C., stirred for 30 minutes, filtered out, washed three times, and dried at 100° C. to obtain stearic acid-modified palygorskite fiber.
[0074] In this embodiment, the palygorskite fiber is fibrous palygorskite with a length ranging from 0.2 to 2 μm.
[0075] Preparation Example 9
[0076] The only difference between this Preparation Example and Preparation Example 11 is that the mass of stearic acid is 30% of the mass of the palygorskite fiber.
[0077] Preparation Example 10
[0078] The only difference between this Preparation Example and Preparation Example 11 is that the mass of stearic acid is 50% of the mass of the palygorskite fiber.
[0079] Preparation Example 11
[0080] The only difference between this Preparation Example and Preparation Example 11 is that the mass of stearic acid is 70% of the mass of the palygorskite fiber.
[0081] Example
[0082] Example 1
[0083] This embodiment discloses a thermal insulation mortar, including the following components by mass: 4 kg cement, 4.5 kg fly ash, 1.2 kg redispersible latex powder, 4.5 kg glass beads, 1 kg microsilica powder, 0.6 kg modified palygorskite fiber, 0.8 kg polyacrylamide grafted basalt fiber, 0.2 kg cellulose ether, 0.5 kg water reducer, and 0.2 kg retarder.
[0084] In this embodiment, the cement is ordinary Portland cement, the fly ash is Class II fly ash, the model of the redispersible latex powder is SWF-05, the modified palygorskite fiber is prepared by Preparation Example 10, the polyacrylamide grafted basalt fiber is prepared by Preparation Example 1, the cellulose ether is hydroxyethyl cellulose ether, the water reducer is SM-F10 melamine high-efficiency water reducer, and the retarder is calcium gluconate.
[0085] The preparation method of thermal insulation mortar comprises the following steps:
[0086] The above-mentioned mass of cement, fly ash, redispersible latex powder, palygorskite fiber, polyacrylamide grafted basalt fiber, cellulose ether, water reducer and retarder were stirred and mixed for 4 minutes, and then glass beads and microsilica powder were added and stirred for 1 minute to obtain thermal insulation mortar.
[0087] Example 2
[0088] The only difference between this embodiment and Example 1 is that the thermal insulation mortar includes the following components in mass: 5 kg cement, 3 kg fly ash, 0.8 kg redispersible latex powder, 3 kg glass beads, 2.5 kg microsilica powder, 1 kg modified palygorskite fiber, 1.5 kg polyacrylamide grafted basalt fiber, 0.5 kg cellulose ether, 0.8 kg water reducer, and 0.5 kg retarder.
[0089] Examples 3-8
[0090] Examples 3-8 are basically the same as Example 1, except that the polyacrylamide grafted basalt fibers are prepared from Preparation Examples 2-7.
[0091] Examples 9-11
[0092] Examples 9-11 are basically the same as Example 1, except that the polyacrylamide grafted basalt fibers are prepared by Preparation Examples 9-11.
[0093] Comparative Example
[0094] Comparative Example 1
[0095] The only difference between this comparative example and Example 1 is that the thermal insulation mortar includes the following components in mass: 4 kg cement, 4.5 kg fly ash, 1.2 kg redispersible latex powder, 5.9 kg glass microspheres, 1 kg microsilica powder, 0.2 kg cellulose ether, 0.5 kg water reducer, and 0.2 kg retarder.
[0096] Comparative Example 2
[0097] The only difference between this comparative example and Example 1 is that the thermal insulation mortar includes the following components in mass: 4 kg cement, 4.5 kg fly ash, 1.2 kg redispersible latex powder, 5.1 kg glass beads, 1 kg microsilica powder, 0.8 kg polyacrylamide grafted basalt fiber, 0.2 kg cellulose ether, 0.5 kg water reducer, and 0.2 kg retarder.
[0098] Comparative Example 3
[0099] The only difference between this comparative example and Example 1 is that the thermal insulation mortar includes the following components in mass: 4 kg cement, 4.5 kg fly ash, 1.2 kg redispersible latex powder, 5.3 kg glass microspheres, 1 kg microsilica powder, 0.6 kg modified palygorskite fiber, 0.2 kg cellulose ether, 0.5 kg water reducer, and 0.2 kg retarder.
[0100] Comparative Example 4
[0101] This comparative example differs from Example 1 only in that the modified palygorskite fiber is replaced with unmodified palygorskite fiber, and the polyacrylamide-grafted basalt fiber is replaced with unmodified basalt fiber. Specifically, the thermal insulation mortar comprises the following components by mass: 4 kg cement, 4.5 kg fly ash, 1.2 kg redispersible latex powder, 4.5 kg glass microspheres, 1 kg microsilica fume, 0.6 kg palygorskite fiber, 0.8 kg basalt fiber, 0.2 kg cellulose ether, 0.5 kg water reducer, and 0.2 kg retarder.
[0102] Comparative Example 5
[0103] This comparative example differs from Example 1 only in that the modified palygorskite fiber is replaced with unmodified palygorskite fiber. Specifically, the thermal insulation mortar comprises the following components by mass: 4 kg cement, 4.5 kg fly ash, 1.2 kg redispersible latex powder, 4.5 kg glass microspheres, 1 kg microsilica fume, 0.6 kg palygorskite fiber, 0.8 kg polyacrylamide-grafted basalt fiber, 0.2 kg cellulose ether, 0.5 kg water reducer, and 0.2 kg retarder.
[0104] Comparative Example 6
[0105] This comparative example differs from Example 1 only in that the polyacrylamide-grafted basalt fiber is replaced with unmodified basalt fiber. Specifically, the thermal insulation mortar comprises the following components: 4 kg cement, 4.5 kg fly ash, 1.2 kg redispersible latex powder, 4.5 kg glass microspheres, 1 kg microsilica fume, 0.6 kg modified palygorskite fiber, 0.8 kg basalt fiber, 0.2 kg cellulose ether, 0.5 kg water reducer, and 0.2 kg retarder.
[0106] Performance test test 1: referring to JC / T 951-2005 "Test method for crack resistance of cement mortar", the cracking index of the thermal insulation mortar of each embodiment and each comparative example was tested;
[0107] Test 2: Referring to JGJ / T 70-2009 "Standard for Test Methods for Basic Properties of Building Mortar", the 14d tensile bonding properties and 28d compressive strength of the thermal insulation mortars of each embodiment and each comparative example were tested.
[0108] The results are summarized in Table 1.
[0109] Table 1
[0110]
[0111]
[0112] Combining Example 1 and Comparative Examples 1-3 with Table 1, it can be seen that the addition of polyacrylamide-grafted basalt fiber and modified palygorskite fiber as anti-cracking fibers to the insulation mortar can significantly improve the insulation mortar's crack resistance and contribute to the improvement of the insulation mortar's bonding strength and mechanical strength. The polyacrylamide-grafted basalt fiber and modified palygorskite fiber work synergistically to form an inorganic fiber network in the insulation mortar. They interact with the redispersible latex powder to form an organic network structure, bonding the various components of the insulation mortar together. This promotes the improvement of the insulation mortar's crack resistance, helps improve the insulation mortar's performance, and expands its application range.
[0113] From Example 1, Comparative Examples 4-6 and Table 1, it can be seen that polyacrylamide grafting modification of basalt fiber and surface modification of palygorskite fiber can promote the formation of organic network structure, promote the improvement of toughness and strength of thermal insulation mortar, and help improve the crack resistance of thermal insulation mortar.
[0114] From Example 1, Examples 3-5, and Table 1, it can be seen that when the mass ratio of acrylamide to coupled modified basalt fiber is 0.4:1, the thermal insulation mortar can achieve better crack resistance and strength; however, when the amount of acrylamide added is too much, excessive polyacrylamide is generated and the basalt fiber is excessively wrapped, which may cause excessive curling of the polyacrylamide-grafted basalt fiber, thereby resulting in a decrease in crack resistance and strength.
[0115] Combining Example 1 and Example 6 with Table 1, it can be seen that the selection of basalt fibers with a length range of 4-8 mm can achieve better crack resistance. This may be because the basalt fibers that are too long may curl and entangle themselves after being grafted with polyacrylamide, affecting the dispersion of the polyacrylamide-grafted basalt fibers in the thermal insulation mortar, which may in turn affect the crack resistance and strength of the thermal insulation mortar.
[0116] From Example 1, Examples 7-8, and Table 1, it can be seen that acid etching pretreatment of basalt fiber can further improve the crack resistance and strength of the thermal insulation mortar. This may be because acid etching increases the surface roughness and specific surface area of basalt fiber, and makes the surface of basalt fiber have more abundant active groups, which promotes the bonding strength between basalt fiber and adhesive materials such as cement, and increases the grafting rate of polyacrylamide.
[0117] It can be seen from Example 1, Examples 9-11 and Table 1 that selecting the dosage range of stearic acid within the range disclosed in this application helps to promote the improvement of crack resistance and strength of the thermal insulation mortar and save costs; when the amount of stearic acid is too much, the active groups of the palygorskite fiber have been fully reacted, and the grafting effect of stearic acid has no obvious change.
[0118] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.
Claims
1. A thermal insulation mortar, characterized in that: The invention comprises the following components in parts by weight: 40-50 parts of cement, 30-45 parts of fly ash, 8-15 parts of redispersible latex powder, 30-45 parts of glass microspheres, 10-25 parts of microsilica fume, 6-10 parts of palygorskite fiber, 8-15 parts of polyacrylamide grafted basalt fiber, 2-5 parts of cellulose ether, 5-8 parts of water reducer, and 2-5 parts of retarder; The palygorskite fiber is stearic acid modified palygorskite fiber; the preparation method of the polyacrylamide grafted basalt fiber comprises the following steps: under ultrasonic conditions, immersing the basalt fiber in a 0.8-1.2 mol / L hydrochloric acid solution, treating for 2-4 hours, filtering out, washing to neutrality, and drying to obtain pretreated basalt fiber; adding a silane coupling agent to an ethanol solution to prepare a 5-10 wt% coupling agent solution, adjusting the pH value to 4-5, immersing the pretreated basalt fiber therein, dispersing it evenly, immersing it for 20-40 minutes, filtering out, washing, and drying to obtain coupled modified basalt fiber; ultrasonically dispersing the coupled modified basalt fiber in water, heating it to 80-100° C. under a nitrogen atmosphere, and stirring it while adding the coupling agent solution. ammonium persulfate is added, followed by acrylamide, and the mixture is stirred for 6-9 hours, filtered, washed, and dried to obtain polyacrylamide-grafted modified basalt fiber; the mass ratio of acrylamide to coupled modified basalt fiber is (0.1-0.6):1; the mass of ammonium persulfate is 1-3% of the mass of acrylamide; the length of the basalt fiber is 4-8 mm; the preparation method of the stearic acid-modified palygorskite fiber comprises: mixing stearic acid and palygorskite fiber into water, heating to 90-120° C., stirring for 10-30 minutes, filtering out, and drying to obtain stearic acid-modified palygorskite fiber; the mass of the stearic acid is 10-50% of the palygorskite fiber; and the length of the palygorskite fiber is 0.2-2 μm.
2. The thermal insulation mortar according to claim 1, characterized in that: The water reducing agent is a melamine high efficiency water reducing agent.
3. The thermal insulation mortar according to claim 1, characterized in that: The retarder is a combination of one or more of calcium gluconate, sodium citrate, calcium citrate, calcium superphosphate, zinc sulfate, and sodium lignosulfonate.
4. A thermal insulation mortar according to any one of claims 1 to 3, characterized in that: The following steps are involved: According to the proportion, cement, fly ash, redispersible latex powder, palygorskite fiber, polyacrylamide grafted basalt fiber, cellulose ether, water reducer and retarder are stirred and mixed for 3-5 minutes, and then glass beads and microsilica powder are added and stirred for 1-2 minutes to obtain thermal insulation mortar.