Thermal insulation concrete and method for manufacturing the same

Abstract

The application discloses a kind of heat-insulating concrete and its preparation method, heat-insulating concrete is according to weight part, including following component: 150-200 parts of cement, 200-250 parts of coarse aggregate, 300-420 parts of fine aggregate, 120-200 parts of light aggregate, 50-90 parts of water, wherein, light aggregate uses modified polyurethane microbead, modified polyurethane microbead is obtained by polyurethane microbead surface growth metal organic framework.The building prepared by the concrete of the application can maintain good heat-insulating performance and mechanical properties for a long time, the indoor environment is warm in winter and cool in summer, suitable for office and residence.

Description

Technical Field

[0001] This application relates to the field of concrete, and in particular to a thermally insulating concrete and its preparation method. Background Technology

[0002] Concrete is a commonly used building material with advantages such as high strength, good flame retardancy, and low raw material cost.

[0003] However, due to the high thermal conductivity and high structural density of concrete, buildings constructed with concrete have poor thermal insulation and heat insulation performance.

[0004] Currently, the main method to improve the thermal insulation effect of concrete buildings is to apply a heat insulation coating to the concrete surface. However, commonly used heat insulation materials such as polyurethane release formaldehyde during use, which can affect human health. In addition, polyurethane is easily affected by the environment and ages and deforms, which reduces the thermal insulation performance of concrete. Summary of the Invention

[0005] To address the problem that concrete lacks long-term thermal insulation properties, this application provides a thermally insulating concrete and its preparation method.

[0006] In a first aspect, a thermally insulating concrete comprises the following components: 150-200 parts cement, 200-250 parts coarse aggregate, 300-420 parts fine aggregate, 120-200 parts lightweight aggregate, and 50-90 parts water, wherein the lightweight aggregate is modified polyurethane microspheres, and the modified polyurethane microspheres are obtained by grafting polyurethane microspheres with a metal-organic framework.

[0007] Typically, but not restrictively, the coarse aggregate is crushed stone, and the fine aggregate is river sand.

[0008] By adopting the above technical solutions, including some lightweight aggregate in the aggregate can increase the porosity of concrete, reduce its density and thermal conductivity, further reduce the thermal bridging effect, and thus improve the thermal insulation performance of concrete. Microspheres, as lightweight materials, have a low thermal conductivity, which can improve the overall thermal conductivity of concrete and reduce its density, thereby improving its thermal insulation performance. In addition, as lightweight aggregate, microspheres can reduce the overall weight of concrete, reducing the building's self-weight and thus reducing structural loads, improving seismic performance, reducing building cracks, and increasing the building's service life. Modified polyurethane microspheres are preferred as the lightweight aggregate. Polyurethane has low thermal conductivity, and polyurethane microspheres have good stability, are not easily reacted with other raw materials, and are not easily decomposed or dissolved in concrete, thus giving the concrete building long-lasting thermal insulation performance. Furthermore, polyurethane microspheres have high strength; when increased building porosity leads to a decrease in mechanical properties, incorporating polyurethane microspheres can improve the mechanical properties of concrete. Polyurethane microspheres are obtained by modifying them with a metal-organic framework (MOF). When MOFs are incorporated into concrete, their porous crystalline structure allows for adjustment of concrete porosity and control of pore size distribution, thereby improving the thermal insulation performance of concrete structures. Furthermore, MOFs possess certain mechanical strength and porous structure, which improves the microstructure of concrete. They also act as catalysts during metal ion dissociation, promoting hydration reactions and enhancing the mechanical properties of concrete. After modification with MOFs, the porous structure, large specific surface area, and good adsorption capacity of the MOFs improve the aggregation of polyurethane microspheres and enhance their dispersion in concrete structures, further improving their thermal insulation performance. Additionally, MOFs can form a protective film on the surface of the polyurethane microspheres, reducing aging and decomposition and improving the long-term thermal insulation performance of concrete structures. Finally, MOFs also improve the mechanical properties of polyurethane, thus enhancing the mechanical properties of concrete structures.

[0009] Preferably, the polyurethane microspheres comprise the following components in parts by weight: 20-45 parts polyether polyol, 10-15 parts...

[0010] Isocyanate, 3-5 parts crosslinking agent, 0.4-1.6 parts emulsifier, 0.4-2.6 parts surfactant and 0.08-0.12 parts stabilizer.

[0011] Typically, but not limitingly, the polyether polyol is trimethylolpropane polyoxyethylene ether triol, the isocyanate is isophorone diisocyanate, the crosslinking agent is sodium alginate, the emulsifier is triadecyl hexametaphosphate, and the stabilizer is polyethylene.

[0012] By adopting the above technical solution and using the above-mentioned raw materials, the polyurethane microspheres prepared and incorporated into concrete result in concrete buildings with good thermal insulation performance and good mechanical properties.

[0013] Preferably, the surfactant is any one of sodium dodecylbenzenesulfonate and sodium dodecyl sulfate.

[0014] By adopting the above technical solutions, anionic surfactants have higher structural stability, which can improve the structural stability of polyurethane microspheres and enhance the long-term thermal insulation performance of concrete. In addition, anionic surfactants have better hydrophilicity, which can better regulate the particle size of emulsion particles during emulsification, thereby improving the uniformity of polyurethane microspheres. Furthermore, the polyurethane microspheres are modified through organometallic frameworks, which further improves the dispersibility of polyurethane microspheres and enhances the thermal insulation effect.

[0015] Preferably, the raw materials for the polyurethane microspheres also include itaconic acid, and the weight ratio of itaconic acid to isocyanate is (1-4):(10-15).

[0016] By adopting the above technical solution and adding itaconic acid containing polycarboxylic acid groups as a raw material, the number of surface active groups of polyurethane microspheres is increased, the surface activity of polyurethane is improved, thereby improving the bonding strength between polyurethane and metal-organic framework, improving the dispersibility of polyurethane particles, and improving the thermal insulation performance of concrete buildings.

[0017] Preferably, the polyurethane microspheres are prepared by the following steps:

[0018] Preparation of prepolymer: Polyether polyol, isocyanate, itaconic acid and crosslinking agent are mixed and reacted to obtain prepolymer;

[0019] Emulsification: Add surfactants and emulsifiers to the prepolymer, add water and stir to obtain an emulsion;

[0020] Preparation of microspheres: A stabilizer is added to the emulsion, reacted, and shaped to obtain polyurethane microspheres.

[0021] Typical, but not limiting, the reaction temperature in the prepolymer preparation step is 70-90℃ and the reaction time is 50-70 min; in the emulsification step, the stirring temperature is 50-70℃ and the stirring time is 4-6 h; in the microsphere preparation step, the reaction time is 1-3 h and the molding time is 30-50 min.

[0022] By adopting the above technical solutions and optimizing the preparation process of polyurethane microspheres, polyurethane microspheres with more uniform particle size can be obtained, thereby improving the thermal insulation effect of buildings.

[0023] Preferably, the modified polyurethane microspheres comprise the following components in parts by weight: 52-65 parts polyurethane microspheres, 21-38 parts magnesium nitrate, and 8-20 parts trimesic acid.

[0024] By adopting the above technical solution, the raw material of the metal-organic frame, with magnesium ions in the metal core, reacts with alkaline substances in concrete to form dense magnesium-calcium stone. This substance fills the voids inside the concrete, thereby improving the building's density, reducing its overall thermal conductivity, and reflecting internal heat radiation to reduce heat loss and improve its thermal insulation performance. Furthermore, the filling of magnesium-calcium stone and the regulation of hydration reactions by magnesium ions both reduce the formation and size of pores inside the concrete, thus improving its density and consequently its compressive and tensile strength. The organic ligand of the metal-organic framework is pyromellitic acid, which can form a metal-organic framework with magnesium ions. It has a large specific surface area, good structural stability, and strong adsorption capacity, which can improve the dispersibility of polyurethane microspheres and the adhesion between lightweight aggregates and cement paste. In addition, pyromellitic acid can also improve the internal structure of concrete, reduce the formation and size of pores, improve the density and toughness of concrete, and synergistically improve the thermal insulation performance and compressive strength of concrete with polyurethane microspheres.

[0025] Preferably, the raw materials for the modified polyurethane microspheres further include tetrabutyl titanate, and the weight ratio of tetrabutyl titanate to magnesium nitrate is (40-46):(21-38).

[0026] By adopting the above technical solution and selecting titanium ions as the second metal center, the electron transfer between metal components can produce a synergistic effect, which can regulate the structural stability of the metal-organic framework and control the dissociation / association rate of metal ions. This improves the problem of easy destruction of the metal-organic framework in concrete, enhances the stability of modified polyurethane microspheres, and thus improves the long-term thermal insulation effect of buildings. The metal-organic framework formed by titanium ions combined with trimesic acid has a strong ultraviolet light absorption capacity and antibacterial effect, which can reduce the aging of polyurethane caused by microorganisms and ultraviolet light, thereby maintaining the thermal insulation performance and mechanical properties of concrete buildings.

[0027] Preferably, the lightweight aggregate is prepared by the following steps:

[0028] Surface modification: Polyurethane microspheres were subjected to plasma treatment to obtain surface-modified polyurethane microspheres;

[0029] Growth of metal-organic frameworks: Tetrabutyl titanate and magnesium nitrate were dissolved in methanol to obtain a mixed solution. Surface-modified polyurethane microspheres and trimesic acid were added to the mixed solution, and the modified polyurethane microspheres were obtained by hydrothermal reaction.

[0030] In typical but not limiting steps of metal-organic framework growth, the hydrothermal reaction occurs at a temperature of 160-200 °C for 2.5-3.5 h.

[0031] By adopting the above technical solution, the surface activity of polyurethane microspheres can be improved and active groups can be provided after plasma treatment, thereby enhancing the bonding ability between polyurethane and metal-organic frameworks. In addition, polyurethane microspheres will form more groove structures, which facilitates the growth of metal ions and organic ligands on their surface to form metal-organic frameworks, thereby improving the modification effect of modified polyurethane microspheres.

[0032] Secondly, a method for preparing thermally insulating concrete includes the following steps:

[0033] Preparation of cement slurry: Water and cement are mixed to obtain cement slurry;

[0034] Preparation of cement mortar: Cement slurry is mixed with coarse and fine aggregates to obtain cement mortar;

[0035] Preparation of thermal insulation concrete: Cement mortar is mixed with lightweight aggregate to obtain thermal insulation concrete.

[0036] Typically, without limitation, the mixing time is 60-80 seconds in the preparation of cement slurry; 2-4 minutes in the preparation of cement mortar; and 30-40 minutes in the preparation of thermal insulation concrete.

[0037] By adopting the above technical solution and the above preparation method, the thermal insulation concrete has more uniform dispersion of each component and better compactness, which makes the concrete have better thermal insulation performance and mechanical properties.

[0038] In summary, this application has the following beneficial effects:

[0039] 1. By using modified polyurethane microspheres as lightweight aggregate, the overall thermal conductivity of the concrete is reduced, thereby improving its overall thermal insulation performance. Furthermore, because they are incorporated into the concrete as a raw material rather than coated on the surface, they are less susceptible to damage from the external environment, thus enhancing the durability of the concrete's thermal insulation properties.

[0040] 2. Modified polyurethane microspheres are obtained by growing magnesium and titanium binary metal-organic frameworks on the surface of polyurethane microspheres. On the one hand, this improves the dispersibility of polyurethane microspheres in the system and enhances their effect; on the other hand, the metal-organic framework can also work synergistically with polyurethane microspheres to further improve the thermal insulation performance and compressive strength of concrete. Detailed Implementation

[0041] The raw materials used in the examples and preparation examples are all commercially available and described in detail below. The present application will be further described in detail below with reference to the examples.

[0042] Preparation examples of raw materials and / or intermediates

[0043] Preparation of polyurethane microspheres

[0044] Preparation Example 0-1: A polyurethane microsphere was prepared using the following steps:

[0045] Preparation of prepolymer: 23 kg of trimethylolpropane polyoxyethylene ether triol, 12.5 kg of isophorone diisocyanate, 2.5 kg of itaconic acid and 4 kg of sodium alginate were mixed and reacted at 80°C for 60 min to obtain the prepolymer;

[0046] Emulsification: Add 1.5 kg sodium dodecylbenzenesulfonate and 1 kg triazopropanol hexametaphosphate to the prepolymer, add 100 L of water, and stir at 60 °C for 5 h to obtain an emulsion;

[0047] Preparation of microspheres: 0.1 kg of polyethylene was added to the emulsion and reacted for 2 h. The mixture was then poured into a mold and molded at 60 °C for 40 min to obtain polyurethane microspheres.

[0048] Preparation Example 0-2: A polyurethane microsphere was prepared using the following steps:

[0049] Preparation of prepolymer: Mix 45 kg of trimethylolpropane polyoxyethylene ether triol, 15 kg of isophorone diisocyanate, 4 kg of itaconic acid and 5 kg of sodium alginate, and react at 70°C for 70 min to obtain prepolymer;

[0050] Emulsification: Add 2.6 kg sodium dodecylbenzenesulfonate and 1.6 kg triadecyl hexametaphosphate to the prepolymer, add 100 L of water, and stir at 70 °C for 4 h to obtain an emulsion;

[0051] Preparation of microspheres: 0.12 kg of polyethylene was added to the emulsion and reacted for 3 h. The mixture was then poured into a mold and molded at 60 °C for 50 min to obtain polyurethane microspheres.

[0052] Preparation Examples 0-3: A type of polyurethane microsphere was prepared using the following steps:

[0053] Preparation of prepolymer: Mix 20 kg of trimethylolpropane polyoxyethylene ether triol, 10 kg of isophorone diisocyanate, 1 kg of itaconic acid and 3 kg of sodium alginate, and react at 90 °C for 50 min to obtain prepolymer;

[0054] Emulsification: Add 0.4 kg sodium dodecylbenzenesulfonate and 0.4 kg triadecyl hexametaphosphate to the prepolymer, add 100 L of water, and stir at 50 °C for 6 h to obtain an emulsion;

[0055] Preparation of microspheres: 0.08 kg of polyethylene was added to the emulsion and reacted for 1 h. The mixture was then poured into a mold and molded at 60 °C for 30 min to obtain polyurethane microspheres.

[0056] Preparation Example 0-4, a polyurethane microsphere, differs from Preparation Example 0-1 in that itaconic acid is replaced with an equal amount of methyl diisocyanate.

[0057] Preparation of modified polyurethane microspheres

[0058] Preparation Example 1-1: A modified polyurethane microsphere was prepared using the following steps:

[0059] Surface modification: 58 kg of polyurethane microspheres were placed in a plasma treatment machine for plasma treatment to obtain surface-modified polyurethane microspheres.

[0060] Growth of metal-organic frameworks: 43 kg of tetrabutyl titanate and 29 kg of magnesium nitrate were dissolved in 200 L of methanol to obtain a mixed solution. Surface-modified polyurethane microspheres and 14 kg of trimesic acid were added to the mixed solution, and the mixture was hydrothermally reacted at 180 °C for 3 h to obtain modified polyurethane microspheres.

[0061] The polyurethane microspheres were derived from preparation example 0-1.

[0062] Preparation Examples 1-2: A modified polyurethane microsphere was prepared using the following steps:

[0063] Surface modification: 65 kg of polyurethane microspheres were placed in a plasma treatment machine for plasma treatment to obtain surface-modified polyurethane microspheres.

[0064] Growth of metal-organic frameworks: 46 kg of tetrabutyl titanate and 38 kg of magnesium nitrate were dissolved in 200 L of methanol to obtain a mixed solution. Surface-modified polyurethane microspheres and 20 kg of trimesic acid were added to the mixed solution, and the mixture was hydrothermally reacted at 160 °C for 3.5 h to obtain modified polyurethane microspheres.

[0065] The polyurethane microspheres were derived from preparation examples 0-2.

[0066] Preparation Examples 1-3: A modified polyurethane microsphere was prepared using the following steps:

[0067] Surface modification: 52 kg of polyurethane microspheres were placed in a plasma treatment machine for plasma treatment to obtain surface-modified polyurethane microspheres.

[0068] Growth of metal-organic frameworks: 40 kg of tetrabutyl titanate and 21 kg of magnesium nitrate were dissolved in 200 L of methanol to obtain a mixed solution. Surface-modified polyurethane microspheres and 8 kg of trimesic acid were added to the mixed solution, and the mixture was subjected to hydrothermal reaction at 200 °C for 2.5 h to obtain modified polyurethane microspheres.

[0069] The polyurethane microspheres were derived from preparation examples 0-3.

[0070] Preparation Examples 1-4: A modified polyurethane microsphere was prepared using the following steps:

[0071] Growth of metal-organic frameworks: 43 kg of tetrabutyl titanate and 29 kg of magnesium nitrate were dissolved in 200 L of methanol to obtain a mixed solution. 58 kg of polyurethane microspheres and 14 kg of trimesic acid were added to the mixed solution, and the mixture was hydrothermally reacted at 180 °C for 3 h to obtain modified polyurethane microspheres.

[0072] The polyurethane microspheres were derived from preparation example 0-1.

[0073] Preparation Examples 1-5: A modified polyurethane microsphere was prepared using the following steps:

[0074] Surface modification: 58 kg of polyurethane microspheres were placed in a plasma treatment machine for plasma treatment to obtain surface-modified polyurethane microspheres.

[0075] Growth of metal-organic frameworks: 29 kg of magnesium nitrate was dissolved in 200 L of methanol to obtain a mixed solution. Surface-modified polyurethane microspheres and 14 kg of trimesic acid were added to the mixed solution, and the mixture was hydrothermally reacted at 180 °C for 3 h to obtain modified polyurethane microspheres.

[0076] The polyurethane microspheres were derived from preparation example 0-1.

[0077] Preparation Examples 1-6: A modified polyurethane microsphere, which differs from Preparation Example 1-1 in that magnesium nitrate is replaced by an equal amount of copper nitrate (i.e., the metal center is copper ions and titanium ions).

[0078] Preparation Examples 1-7, a modified polyurethane microsphere, differs from Preparation Examples 1-5 in that magnesium nitrate is replaced by an equal amount of copper nitrate (i.e., the metal center is copper ions).

[0079] Preparation Examples 1-8: A modified polyurethane microsphere, which differs from Preparation Example 1-1 in that the polyurethane microsphere is derived from Preparation Example 0-4.

[0080] Example

[0081] Example 1: A thermally insulating concrete, prepared using the following steps:

[0082] Preparation of cement slurry: Mix 70 kg of water and 175 kg of cement for 70 seconds to obtain cement slurry;

[0083] Preparation of cement mortar: Take cement slurry, add 225 kg of crushed stone and 360 kg of river sand, mix and stir for 3 minutes to obtain cement mortar;

[0084] Preparation of thermal insulation concrete: Take cement mortar and add 160kg of lightweight aggregate, mix and stir for 35 minutes to obtain thermal insulation concrete.

[0085] The lightweight aggregate uses modified polyurethane microspheres, which are derived from Preparation Example 1-1.

[0086] Example 2: A thermally insulating concrete, prepared using the following steps:

[0087] Preparation of cement slurry: Mix 90kg of water and 200kg of cement for 60s to obtain cement slurry;

[0088] Preparation of cement mortar: Take cement slurry, add 250kg of crushed stone and 420kg of river sand, mix and stir for 4 minutes to obtain cement mortar;

[0089] Preparation of thermal insulation concrete: Take cement mortar, add 200 kg of lightweight aggregate, mix and stir for 40 min to obtain thermal insulation concrete.

[0090] The lightweight aggregate uses modified polyurethane microspheres, which are derived from preparation examples 1-2.

[0091] Example 3: A thermally insulating concrete, prepared using the following steps:

[0092] Preparation of cement slurry: Mix 50kg of water and 150kg of cement for 80s to obtain cement slurry;

[0093] Preparation of cement mortar: Take cement slurry, add 200kg of crushed stone and 300kg of river sand, mix and stir for 3 minutes to obtain cement mortar;

[0094] Preparation of thermal insulation concrete: Take cement mortar, add 120kg of lightweight aggregate, mix and stir for 30 minutes to obtain thermal insulation concrete.

[0095] The lightweight aggregate uses modified polyurethane microspheres, which are derived from preparation examples 1-3.

[0096] Example 4, a thermal insulation concrete, differs from Example 1 in that the modified polyurethane microspheres are derived from Preparation Examples 1-4.

[0097] Example 5, a thermal insulation concrete, differs from Example 1 in that the modified polyurethane microspheres are derived from Preparation Examples 1-5.

[0098] Example 6, a thermal insulation concrete, differs from Example 1 in that the modified polyurethane microspheres are derived from Preparation Examples 1-6.

[0099] Example 7, a thermal insulation concrete, differs from Example 1 in that the modified polyurethane microspheres are derived from Preparation Examples 1-7.

[0100] Example 8, a thermal insulation concrete, differs from Example 1 in that the modified polyurethane microspheres are derived from Preparation Examples 1-8.

[0101] Comparative Example

[0102] Comparative Example 1, a thermal insulation concrete, differs from Example 1 in that the lightweight aggregate uses polyurethane microparticles derived from Preparation Example 0-1.

[0103] Comparative Example 2, a thermal insulation concrete, was prepared using the following steps:

[0104] Preparation of cement slurry: Mix 70 kg of water and 175 kg of cement for 70 seconds to obtain cement slurry;

[0105] Preparation of cement mortar: Mix cement paste with 225kg of crushed stone and 360kg of river sand for 38 minutes to obtain the concrete base layer; Preparation of thermal insulation concrete: Coat the surface of the concrete base layer with polyurethane coating to obtain thermal insulation concrete, with a coating dosage of 0.15kg / m². 2 use.

[0106] The polyurethane coating is prepared using the following steps:

[0107] 1) One-time ingredient preparation

[0108] Open the feeding port, and the operator adds 20kg of polyether polyol and 15kg of petroleum resin to the reactor according to the formula. Cover the feeding port, turn on the stirring button of the reactor, and record the time and temperature.

[0109] 2) Heating, dehydration, and secondary batching

[0110] ① Close the inlet and outlet valves of the reactor, open the drain valve at the bottom of the reactor, and then open the steam inlet valve of the reactor to 1 / 3. First, add a small amount of steam for preheating. After 5 minutes, fully open the steam inlet valve of the reactor (especially important in winter) to heat up. After all the water in the jacket is drained, close the drain valve at the bottom of the reactor (do not close it tightly, leave a small gap). When the temperature of the material in the reactor rises to 100±10℃ (record), turn off the reactor stirring button, add 12.5kg of nano-grade heavy calcium carbonate into the reactor according to the formula, turn on the reactor stirring button, and continue to heat up.

[0111] ② When the material temperature inside the reactor reaches 80℃ (record), open the water inlet valves of the condenser and vacuum pump. After confirming that the return water is normal, start the vacuum pump, open the vacuum valve on the vacuum pump, close the vent valve of the vacuum gauge on the reactor, close the stirring button of the reactor, and slowly open 1 / 5 of the vacuum valve on the reactor. After 10 minutes, open the stirring button of the reactor. When the negative pressure of the vacuum gauge on the reactor reaches -0.08MPa, fully open the vacuum valve on the reactor. When the material temperature inside the reactor reaches 105℃, close the steam inlet valve of the reactor (record). Dehydrate for 60 minutes with the negative pressure of the vacuum gauge on the reactor not exceeding -0.085MPa (material temperature controlled between 105℃ and 110℃). After dehydration is completed, close the vacuum valve on the reactor, open the vent valve of the vacuum gauge, then close the vacuum valve on the vacuum pump, and turn off the vacuum pump. After 5 minutes, close the water inlet valves of the vacuum pump and condenser.

[0112] 3) Three-stage ingredient preparation:

[0113] After dehydration is complete, turn off the stirring button of the reactor, open the feed port of the reactor, add 5.5 kg of 1,4-dimethylphenyl diisocyanate according to the formula, cover the feed port, turn on the stirring button of the reactor, control the temperature of the material in the reactor at 110℃, and react for 30 minutes.

[0114] 4) Cooling down:

[0115] After the reaction is complete, first open the water outlet valve of the reactor, then open the water inlet valve of the reactor, and close the drain valve tightly. Cool down while stirring, until the temperature of the material inside the reactor drops to 70±5℃.

[0116] 5) Fourth batching: Turn off the stirring button of the reactor, open the feed port of the reactor, and add 2 kg of diisopropyl dithiocarbonyl diamine according to the formula.

[0117] 6) Fifth batching: Cover the feeding port and turn on the stirring button of the reactor for 30 minutes. When the temperature of the material in the reactor drops to 60±℃, add the vitrified microspheres.

[0118] 7) Discharge: Cover the feed port, turn on the stirring button of the reactor and stir for 30 minutes. Then prepare to grind and discharge the material to obtain polyurethane coating.

[0119] Comparative Example 3, a thermal insulation concrete, was prepared using the following steps:

[0120] Preparation of reinforced admixture: Take 20 kg of admixture and 10 kg of reinforcing agent and stir them together. Stir at a speed of 200 r / min for 5 min. Filter, retain the filter cake, wash the filter cake with deionized water until the washing liquid is neutral, and then dry to obtain reinforced admixture.

[0121] Preparation of hardening coating solution: Weigh 10 kg of brucite with a particle size of 2000 mesh, mix brucite with ethanol, and stir for 5 min at a speed of 500 r / min to obtain the hardening coating solution.

[0122] Reinforcing coating: Take the reinforcing admixture and the hardening coating liquid, stir and mix them, and then stir continuously for 10 minutes at 200 r / min under 0.5 MPa to obtain the admixture coated with the hardening layer. Adjust the thickness of the hardening layer to 10 mm.

[0123] Concrete preparation: Take 60kg of aggregate, 20kg of cement, 50kg of water, 4kg of water-reducing agent, and admixtures with a hardening layer, and mix them to obtain heat-insulating concrete.

[0124] The admixture is made of sulfur-fixing ash, and the reinforcing agent is sodium hydroxide.

[0125] Performance testing

[0126] The concrete prepared in Examples 1-8 and Comparative Examples 1-3 was thoroughly mixed and then poured into molds. During the filling process, the concrete in the molds was tamped and the surface was smoothed to obtain several specimens 1 (300×300×30mm) and several specimens 2 (70×70×70mm). Specimen 1 was used to test the thermal conductivity, and specimen 2 was used to test the concrete strength. Specimen 1 and specimen 2 were cured at 20±2℃ for 24 hours and then placed in a curing chamber for standard curing for 28 days.

[0127] Experiment 1: Thermal conductivity test: Take sample 1, put it in an oven, and dry it to constant weight at 95℃. The thermal conductivity of sample 1 was measured according to GB / T10294. The results are shown in Table 1.

[0128] Test 2: Thermal insulation and heat preservation stability test: Take sample 1, put it in an oven, dry it to constant weight at 95℃, and after 180 days, test the thermal conductivity of sample 1 according to GB / T10294. The results are shown in Table 1.

[0129] Experiment 3: Compressive strength test: Place sample 2 under the compressive strength tester and apply slow continuous loading. Record the pressure at which sample 2 develops initial cracks. The results are shown in Table 1.

[0130] Table 1: Performance test results of Examples 1-8 and Comparative Examples 1-3

[0131]

[0132]

[0133] As can be seen from Examples 1-4 and Table 1, the addition of polyurethane microspheres after plasma modification results in concrete with better thermal insulation performance, thermal insulation durability, and compressive strength. This is because plasma treatment improves the surface activity of polyurethane and provides active groups, thereby enhancing the bonding ability between polyurethane and the metal-organic framework. In addition, polyurethane microspheres form more groove structures, which facilitates the growth of metal ions and organic ligands on their surface to form a metal-organic framework, thus improving the modification effect of the modified polyurethane microspheres.

[0134] As can be seen from Examples 1 and 5-7, and Table 1, the concrete prepared with polyurethane microspheres modified with magnesium and titanium ions as the metal center has better thermal insulation performance, thermal insulation durability, and compressive strength. This is because magnesium and titanium ions have a synergistic effect in promoting the dispersion of polyurethane microspheres, improving the rate of cement hydration reaction, and reducing the aging and degradation of polyurethane microspheres. However, when copper ions are used as the metal center, they promote early hardening of cement, reduce the porosity of concrete, and thus reduce the thermal insulation performance of concrete. In addition, copper ions react with aggregates and cement paste, causing cracks, and they also promote the corrosion effect of chloride ions and sulfates, further damaging the concrete and reducing its compressive strength and thermal insulation effect.

[0135] As can be seen from Examples 1 and 8 and Table 1, the addition of itaconic acid can improve the modification effect of polyurethane microspheres.

[0136] As can be seen from Example 1, Comparative Examples 1-3, and Table 1, the thermal insulation concrete prepared by the technical solution of this application has better thermal insulation effect and compressive strength than commercially available thermal insulation concrete. This is because the application uses lightweight aggregate to improve the overall thermal insulation effect of the concrete. In addition, the lightweight aggregate is made of polyurethane microspheres modified with a metal-organic framework. After the polyurethane is modified with a metal-organic framework, the porous structure, large specific surface area, and good adsorption capacity of the metal-organic framework can improve the agglomeration of polyurethane microspheres and improve the dispersion performance of polyurethane microspheres in concrete buildings, thereby further improving the thermal insulation performance of concrete buildings. It can also form a protective film on the surface of polyurethane microspheres, thereby reducing the aging and decomposition of polyurethane microspheres and improving the long-term thermal insulation performance of concrete buildings. The metal-organic framework can also improve the mechanical properties of polyurethane, thereby improving the mechanical properties of concrete buildings.

[0137] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A thermally insulating concrete, characterized in that, The product comprises the following components by weight: 150-200 parts cement, 200-250 parts coarse aggregate, 300-420 parts fine aggregate, 120-200 parts lightweight aggregate, and 50-90 parts water. The lightweight aggregate is made of modified polyurethane microspheres, which are obtained by growing a metal-organic framework on the surface of polyurethane microspheres. The modified polyurethane microspheres comprise the following components in parts by weight: 52-65 parts polyurethane microspheres, 21-38 parts magnesium nitrate, 8-20 parts trimesic acid, and tetrabutyl titanate, wherein the weight ratio of tetrabutyl titanate to magnesium nitrate is (40-46):(21-38). The polyurethane microspheres comprise the following components in parts by weight: 20-45 parts polyether polyol, 10-15 parts isocyanate, 3-5 parts crosslinking agent, 0.4-1.6 parts emulsifier, 0.4-2.6 parts surfactant, 0.08-0.12 parts stabilizer, and itaconic acid, wherein the weight ratio of itaconic acid to isocyanate is (1-4):(10-15).

2. The thermal insulation concrete according to claim 1, characterized in that, The surfactant is either sodium dodecylbenzenesulfonate or sodium dodecyl sulfate.

3. The thermal insulation concrete according to claim 1, characterized in that, The polyurethane microspheres are prepared by the following steps: Preparation of prepolymer: Polyether polyol, isocyanate, itaconic acid and crosslinking agent are mixed and reacted to obtain prepolymer; Emulsification: Add surfactants and emulsifiers to the prepolymer, add water and stir to obtain an emulsion; Preparation of microspheres: A stabilizer is added to the emulsion, reacted, and shaped to obtain polyurethane microspheres.

4. The thermal insulation concrete according to claim 1, characterized in that, The lightweight aggregate is prepared by the following steps: Growth of metal-organic frameworks: Tetrabutyl titanate and magnesium nitrate were dissolved in methanol to obtain a mixed solution. Polyurethane microspheres and trimesic acid were added to methanol, and a hydrothermal reaction was carried out to obtain modified polyurethane microspheres.

5. The thermal insulation concrete according to claim 4, characterized in that, The lightweight aggregate is prepared by the following steps: Surface modification: Polyurethane microspheres were subjected to plasma treatment to obtain surface-modified polyurethane microspheres; Growth of metal-organic frameworks: Tetrabutyl titanate and magnesium nitrate were dissolved in methanol to obtain a mixed solution. Surface-modified polyurethane microspheres and trimesic acid were added to the mixed solution, and the modified polyurethane microspheres were obtained by hydrothermal reaction.

6. A method for preparing thermally insulating concrete according to any one of claims 1-5, characterized in that, Includes the following steps: Preparation of cement slurry: Water and cement are mixed to obtain cement slurry; Preparation of cement mortar: Cement slurry is mixed with coarse and fine aggregates to obtain cement mortar; Preparation of thermal insulation concrete: Cement mortar is mixed with lightweight aggregate to obtain thermal insulation concrete.

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