Infrared radiation cement-based material and preparation method thereof

Abstract

According to the infrared radiation cement-based material and the preparation method thereof provided by the invention, through collaborative design of components such as zirconium silicate (ZrSi O4), silicon carbide, tourmaline powder, hollow glass beads, barite sand and basalt fibers, an infrared radiation functional material is effectively doped into a cement matrix, and on the basis of ensuring the original structural performance of the cement matrix, the infrared radiation functional material is effectively doped into the cement matrix. The infrared emission rate of the infrared radiation cement-based material reaches 0.9 or above, the infrared radiation cement-based material can effectively radiate the infrared band (8-14 microns) of a human body absorption area, the living comfort is improved, all the materials act synergistically, mechanical properties and high infrared radiation performance are both considered, the preparation process is suitable for engineering popularization, and the infrared radiation cement-based material has wide application prospects. The material can be widely applied to the fields of energy-saving walls, floor heating bases, physiotherapy buildings and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building materials, in particular to a cement-based material with infrared radiation function and a preparation method thereof, which is suitable for the fields of thermal insulation, health care buildings, road snow melting and functional building components. BACKGROUND

[0002] Cement-based composite materials, as the most widely used traditional materials in construction engineering, play an important role in infrastructure and building structure fields due to their excellent mechanical properties and good forming and processing properties. With the increasing concern of modern buildings on energy saving, environmental protection and intelligent functions, traditional cement-based materials with only structural bearing function have gradually been difficult to meet the diversified needs of buildings in comfort, health and energy saving. In recent years, the research on functional building materials has gradually risen, especially the far-infrared radiation functional components are compounded to endow the cement-based materials with infrared radiation ability, which becomes an important way to realize the integration of structure and function. Infrared radiation materials can absorb heat energy and effectively release electromagnetic waves in the far-infrared wave band (4-20 μm), promote indoor thermal radiation balance, improve human comfort, have health effects such as improving blood circulation, antibacterial and mildew prevention, and are widely used in green buildings, health care facilities and energy saving systems. However, the current far-infrared functional materials are mostly attached to building components in the form of surface coating or interlayer, which has the problems of weak bonding force with cement matrix, poor thermal stability, insufficient weather resistance, fast functional attenuation and the like, and is difficult to meet the stable infrared radiation demand in long-term service environment. Therefore, it is urgent to effectively dope the infrared radiation functional materials into the cement matrix through multi-component functional synergy, endow the cement matrix with persistent and stable infrared radiation ability on the basis of ensuring its original structural properties, so as to realize the application breakthrough of high-performance and multi-functional cement-based composite materials and meet the development trend of green buildings and functional building materials. SUMMARY

[0003] The present application provides an infrared radiation cement-based material and a preparation method thereof, which realizes the function of infrared radiation through multi-component synergy design, has good thermal stability, mechanical properties and far-infrared emission performance, and can be widely applied in the fields of energy-saving walls, floor heating substrates, physiotherapy buildings and the like.

[0004] An infrared radiation cement-based material, characterized in that the raw materials include the following components in mass fraction:

[0005] Portland cement: 45-55 parts;

[0006] Hollow glass microspheres: 5-10 parts;

[0007] High alumina cement: 5-10 parts;

[0008] Zirconium silicate (ZrSiO4): 8-12 parts;

[0009] Lithium polysilicate: 1-2 parts;

[0010] Silicon carbide: 5-8 parts;

[0011] Tourmaline powder: 2-4 parts;

[0012] Basalt fiber: 2-5 parts;

[0013] Barite sand: 10-20 parts;

[0014] Water reducing agent: 1-2 parts;

[0015] Cellulose ether: 0.5-1 part.

[0016] The particle size of the zirconium silicate (ZrSiO4) is 0.5-5 μm, which is treated with a silane coupling agent.

[0017] The length of the basalt fiber is 12-18 mm, and the diameter is 15-20 μm

[0018] The tourmaline powder is a magnesio-tourmaline with a particle size of no more than 3 μm.

[0019] The particle size of the hollow glass microsphere ranges from 10 to 100 μm.

[0020] The barite sand has a BaSO4 content of ≥95%, and the particle size of the barite sand is 100-200 μm.

[0021] The modulus of the lithium polysilicate is 2.5-3.5, and the solid content is 20-30%.

[0022] The water reducing agent is a polycarboxylic acid water reducing agent.

[0023] The present application relates to a preparation method of an infrared radiation cement-based material, which comprises the following steps:

[0024] (1) Zirconium silicate (ZrSiO4) pretreatment: place the zirconium silicate in an oven and dry it at 120-150°C for 2-4 hours; take 0.5-2.0 wt% of a silane coupling agent based on the mass of the zirconium silicate, add it to anhydrous ethanol or isopropanol, and stir until a coupling agent solution is formed; slowly add the dried zirconium silicate to the coupling agent solution, stir at room temperature for 1 hour, so that the coupling agent fully reacts with the surface of the zirconium silicate particles and forms a dense and stable organic-inorganic interface layer; then dry it at 60-80°C for 10-12 hours and cool it to room temperature to obtain pretreated zirconium silicate.

[0025] (2) Silicon carbide pretreatment: silicon carbide is placed in an oven in an inert atmosphere, heated to 600±10℃ at a heating rate of 10±2℃ / min, and held for 1±0.2 hours, then cooled to room temperature; the high-temperature treated silicon carbide is mixed with anhydrous ethanol at a mass ratio of 1:10, then polyethylene glycol-2000 (PEG-2000) is added, the amount of polyethylene glycol-2000 (PEG-2000) being 0.5-1.0% of the mass of the silicon carbide, and stirred for 30±5 minutes to obtain a slurry; the slurry is vacuum dried at 80±5℃ for 30 minutes, and sieved through a 400-mesh sieve to obtain pretreated silicon carbide.

[0026] (3) Pretreatment of tourmaline powder, the tourmaline powder is dried in an oven at 100-120℃ for 2 hours to remove surface adsorbed water and impurities, and cooled to room temperature; the dried tourmaline powder is dispersed in an appropriate amount of deionized water, and a silane coupling agent is added, the amount of the silane coupling agent being 0.5-2.0% of the mass of the tourmaline powder, and stirred at room temperature for 1 hour to uniformly coat the surface of the tourmaline powder with the coupling agent to form a stable organic-inorganic combined layer; nano-TiO2 ethanol suspension (solid content of TiO2 in the suspension being 5wt%) in an amount of 0.3-0.8% of the mass of the tourmaline powder is added to the material treated with the silane coupling agent, and stirring is continued for 10±1 minutes to construct a composite interface layer with infrared response activity and synergistic radiation ability; then hot air drying and vacuum drying are performed in sequence, i.e. first hot air drying at 80±5℃ for 30 minutes, and then drying under vacuum at -0.08MPa for 30 minutes; after drying is completed, the material is sieved through a 600-mesh vibrating sieve (amplitude controlled at 1.0±0.2mm) to obtain pretreated tourmaline powder with uniform particle size and stable interface structure.

[0027] (4) Dry mixing: silicate cement, high-alumina cement, barite sand, and hollow glass microbeads are added to a mixer and mixed at 150rpm for 5 minutes; pretreated zirconium silicate, pretreated silicon carbide, and pretreated tourmaline powder are added and mixed for another 3 minutes until uniform to obtain a dry mixture.

[0028] (5) Wet mixing: water (water-cement ratio 0.22-0.26) is slowly added to the dry mixture obtained in step (4), and a water reducing agent and cellulose ether are simultaneously added, and the mixture is stirred at 300rpm for 3 minutes to form a homogeneous slurry.

[0029] (6) Basalt fibers and polysilicate lithium are added to the slurry obtained in step (5), and the mixture is stirred at a low speed of 100rpm for 2 minutes to avoid fiber breakage, to obtain a mixed material.

[0030] (7) Molding and curing: the mixed material of step (6) is injected into a mold and vibrated to compact (frequency 50 Hz, time 30 s), and then covered with a plastic film to prevent moisture evaporation; then curing is carried out, the first stage is curing at 20±2℃, humidity ≥95% for 24 h, and then demolding; the second stage is steam curing at 40℃ for 48 h (heating rate 10℃ / h), and then standard curing for 28 days.

[0031] The silane coupling agent in the above preparation method steps is an amino silane coupling agent or an epoxy silane coupling agent, which can be a gamma-aminopropyl triethoxysilane coupling agent (KH-550) or a gamma-glycidyl ether propyl trimethoxysilane coupling agent (KH-560).

[0032] In the above preparation method, the basalt fibers and lithium polysilicate in step (6) are added in three times, each time interval is 30±5 seconds, and each time adds about 1 / 3 of the total amount, and low-speed stirring is carried out for dispersion, so as to avoid fiber fracture or entanglement due to shearing action, and make the lithium polysilicate uniformly distributed in the slurry system. The split-adding process can significantly improve the uniformity of fiber dispersion and the interface bonding effect, while reducing the sudden change of slurry fluidity, thereby improving the molding compactness and mechanical properties.

[0033] The modulus of lithium polysilicate is 2.5-3.5, and the solid content is 20-30%.

[0034] The present application pretreats zirconium silicate by silane coupling agent, because the epoxy group or amino group in the silane coupling agent reacts with Ca 2+The reaction can improve the interface bonding of zirconium silicate and cement, reduce interface defects; at the same time, due to the reduction of interface light scattering loss, the infrared radiation efficiency is improved, in addition, the particle agglomeration is inhibited, and the uniform distribution of the functional components is ensured. The silicon carbide is pretreated, the amorphous silicon dioxide coating layer (about 2-5nm thick) is formed on the surface of the silicon carbide in the air, the infrared emissivity of the silicon dioxide is 0.6, which is much lower than the infrared emissivity of the pure silicon carbide 0.92, the inert atmosphere high temperature treatment of the application removes the oxide layer on the surface of the silicon carbide, and at the same time, the high temperature annealing treatment can eliminate the lattice distortion caused by processing, so that the phonon vibration mode of the silicon carbide is more active, and the emissivity in the 8-14μm wave band is improved (+5-8%), and the drying treatment is because when the water content of the silicon carbide is high, the tricalcium aluminate in the cement reacts to generate an expansive hydration product (such as ettringite), which causes cracking risk; the 400 mesh screen (pore size 38μm) can intercept the agglomerates, and ensure the uniformity of the silicon carbide; the long chain molecules of polyethylene glycol-2000 are adsorbed on the surface of the silicon carbide particles, forming an organic layer with a certain thickness of about 3-5nm, the space stretching of the PEG chain prevents the particles from approaching each other, the hydrophilic group (-OH) of polyethylene glycol combines with the cement pore water to form a hydration film, so that the agglomeration rate of silicon carbide in the cement slurry is reduced, and the dispersion is more uniform, at the same time, polyethylene glycol fills the refractive index difference between silicon carbide and cement matrix (SiC:2.65, cement:1.65, PEG:1.46), forming a refractive index gradient layer (2.65→1.46→1.65) to make the infrared light gradually transmit, reduce the scattering loss, and reduce the interface light loss. The tourmaline powder is pretreated, a certain amount of water and organic and inorganic impurities will be adsorbed on the surface of the tourmaline powder during storage and transportation, which will reduce the infrared radiation efficiency and affect the bonding performance with the cement matrix, the surface adsorbed water and volatile impurities can be effectively removed by 100-120℃ low temperature drying, and the purity and stability are improved; at the same time, the nano TiO2 functional modification can form a synergistic radiation layer on the surface of the tourmaline, which utilizes the scattering and thermal excitation characteristics of TiO2 in the infrared wave band, cooperates with the piezoelectric effect and pyroelectric effect of tourmaline, improves the overall infrared emissivity and radiation intensity, the tourmaline powder particles treated by the coupling agent and nano TiO2 have hydrophilic and hydrophobic dual functional groups on the surface, which can significantly improve the dispersibility in the cement-based system, avoid agglomeration, and the drying and screening (600 mesh) steps ensure the uniform distribution of particle size distribution, which is convenient for uniform distribution in the cement-based material, avoids stress concentration and performance degradation.The basalt fibers are added in one time in the cement-based system, and are prone to be broken, wound or aggregated due to the shearing effect of stirring, so that the distribution is uneven, and the reinforcing effect is affected, the three-time gradual adding mode can gradually disperse in the stirring process, and the mechanical entanglement and shearing fracture between the fibers are reduced, the batch adding can make the fibers uniformly distributed in the whole slurry, avoids local enrichment, ensures the formation of uniform reinforcing network in the cement, and improves the crack resistance, impact resistance and toughness; the lithium polysilicate can react with calcium hydroxide in the cement hydration product to generate C-S-H gel, so that the compactness and mechanical properties of the cement-based material are improved, and a high-strength interface layer is formed between the functional filler (zirconium silicate, silicon carbide, tourmaline powder) and the cement, the fiber and the matrix, so that the overall structural stability and infrared radiation persistence are enhanced. In addition, the dense gel layer generated by the lithium polysilicate can effectively block the penetration of corrosive medium, improve the durability and chemical corrosion resistance of the material, and cooperate with the batch adding process to improve the flowability and uniformity of the mixture, and the three-time adding can avoid the uneven reaction caused by the too high local concentration in an instant, and the fibers and the lithium polysilicate can be distributed in the whole slurry at the same time, so that the interfacial bonding strength and compactness are improved; if a large amount of fibers and lithium polysilicate are added at one time, the slurry viscosity will be increased, the flowability will be reduced, and the forming compactness will be affected. The three-time adding can ensure uniform dispersion while reducing the sudden impact on the flowability of the mixture, which is beneficial to forming and vibrating.

[0035] The infrared radiation mechanism of the infrared radiation cement-based material of the present application is based on the synergistic effect of multiple functional components, and silicate as a matrix material not only provides a solid structural support for the composite system, but also effectively promotes the multiple scattering and transmission of infrared light due to the micro-pore structure formed by solidification. The micro-pore structure enables the infrared waves to be repeatedly reflected and scattered within the material, prolonging the propagation path of the infrared waves in the material and thereby enhancing the intensity and uniformity of the infrared radiation; silicon carbide has high infrared emissivity and excellent thermal conductivity, and the lattice vibration mode in its crystal structure can effectively release heat radiation in the far-infrared wave band, while the high thermal conductivity helps to evenly distribute heat energy within the material, promoting the sustained release and stability of far-infrared radiation; tourmaline powder, with its unique crystal structure, has piezoelectric and pyroelectric effects, and can stimulate infrared radiation enhancement under the action of a small temperature difference or mechanical stress. At the same time, tourmaline powder can release negative ions to improve the environment around the material, further enhancing the overall functional performance of the material; zirconium silicate has good far-infrared emissivity and high-temperature resistance, improving the thermal stability and infrared radiation efficiency of the material and ensuring the performance stability of the material during long-term service; barite sand has stable particle size, high infrared reflectivity, and high heat capacity, and it plays a role in reflecting far-infrared waves in the material, enhancing the intensity of infrared radiation, and maintaining the long-term infrared radiation function of the material by storing and releasing heat energy; hollow glass microspheres have good thermal insulation and lightweight properties, which can effectively reduce the density and thermal conductivity of the material, improve the thermal insulation performance, and their hollow structure helps to scatter infrared radiation multiple times and prolong the transmission path of infrared waves. Lithium polysilicate helps to improve the interface bonding of the material, enhance the overall density and durability of the material, and also promotes infrared radiation. Basalt fiber improves the crack resistance and toughness of the material, and improves the durability and impact resistance of the composite material.

[0036] Compared with the prior art, the present application has the following advantages:

[0037] (1) The infrared radiation cement-based material of the present application has an infrared emissivity of 0.9 or higher, which can effectively radiate infrared waves in the human absorption band (8-14 μm), improving the living comfort; at the same time, the content of BaSO4 in barite sand used in the present application is relatively high, and the present application also has the function of shielding X-rays and gamma rays.

[0038] (2) The synergistic effect of each material takes into account the mechanical properties and infrared function, the preparation process is simple, and it is suitable for engineering promotion;

[0039] (3) The material has strong thermal stability and anti-aging ability, and the far-infrared function is durable, does not depend on external coating, and saves maintenance cost;

[0040] (4) It is suitable for green buildings, maintenance buildings, medical spaces and other application scenarios that have special requirements for thermal radiation and functionalization. DETAILED DESCRIPTION

[0041] In an embodiment, an infrared radiation cement-based material includes the following components in parts by mass:

[0042] Portland cement: 46 parts;

[0043] Hollow glass microbeads: 6 parts;

[0044] High-alumina cement: 7 parts;

[0045] Zirconium silicate (ZrSiO4): 10 parts;

[0046] Lithium polysilicate: 1.5 parts;

[0047] Silicon carbide: 6 parts;

[0048] Tourmaline powder: 3 parts;

[0049] Basalt fiber: 3 parts;

[0050] Barite sand: 16 parts;

[0051] Water reducing agent: 1 part;

[0052] Cellulose ether: 0.5 parts.

[0053] The zirconium silicate (ZrSiO4) has a particle size of 3 μm and is treated with a silane coupling agent.

[0054] The basalt fiber has a length of 16 mm and a diameter of 16 μm.

[0055] The tourmaline powder is a magnesio-tourmaline with a particle size of 2 μm.

[0056] The hollow glass microbeads have a particle size range of 60 μm.

[0057] The barite sand has a BaSO4 content of 97% and a particle size of 150 μm.

[0058] The lithium polysilicate has a modulus of 2.0 and a solid content of 25%.

[0059] The water reducing agent is a polycarboxylic acid water reducing agent.

[0060] The above embodiment one infrared radiation cement-based material preparation method, including the following steps:

[0061] (1) Zirconium silicate (ZrSi04) pretreatment: Zirconium silicate was placed in an oven and dried at 150°C for 3 hours; 2.0wt% silane coupling agent based on the mass of zirconium silicate was added to anhydrous ethanol or isopropanol and stirred uniformly to form a coupling agent solution; the dried zirconium silicate was slowly added to the coupling agent solution and stirred at room temperature for 1 hour to allow the coupling agent to fully react and bond with the surface of the zirconium silicate particles, forming a dense and stable organic-inorganic interface layer; then it was dried at 80°C for 12 hours and cooled to room temperature to obtain pretreated zirconium silicate.

[0062] (2) Silicon carbide pretreatment: Silicon carbide was placed in an oven in an inert atmosphere and heated to 600±10°C at a heating rate of 10±2°C / min, held for 1±0.2 hours, and then cooled to room temperature; the high-temperature treated silicon carbide was mixed with anhydrous ethanol at a mass ratio of 1:10, then polyethylene glycol-2000 (PEG-2000) was added, the amount of PEG-2000 being 1.0% of the mass of silicon carbide, and stirred for 30±5 minutes to obtain a slurry; the slurry was vacuum dried at 80±5°C for 30 minutes and sieved through a 400-mesh sieve to obtain pretreated silicon carbide.

[0063] (3) Pretreatment of tourmaline powder: The tourmaline powder was placed in an oven and dried at 120°C for 2 hours to remove surface adsorbed water and impurities, and then cooled to room temperature; the dried tourmaline powder was dispersed in an appropriate amount of deionized water, and a silane coupling agent was added, the amount of silane coupling agent being 2.0% of the mass of tourmaline powder, and stirred at room temperature for 1 hour to allow the coupling agent to uniformly coat the surface of the tourmaline powder, forming a stable organic-inorganic bonding layer; to the above material treated with silane coupling agent, 0.8% nano-Ti02 ethanol suspension (Ti02 solid content in the suspension is 5wt%) based on the mass of tourmaline powder was added, and stirring was continued for 10±1 minutes to construct a composite interface layer with infrared response activity and synergistic radiation ability; then hot air drying and vacuum drying were carried out in sequence, i.e. first hot air drying at 80±5°C for 30 minutes, and then drying under vacuum conditions of -0.08MPa for 30 minutes; after drying, the material was sieved through a 600-mesh vibrating sieve (amplitude control at 1.0±0.2mm) to obtain pretreated tourmaline powder with uniform particle size and stable interface structure.

[0064] (4) Dry mixing: Silicate cement, high-alumina cement, barite sand, and hollow glass microbeads were added to a mixer and mixed at 150rpm for 5 minutes; pretreated zirconium silicate, pretreated silicon carbide, and pretreated tourmaline powder were added and mixed for another 3 minutes until uniform, to obtain dry mix.

[0065] (5) Wet mixing: water (water-cement ratio 0.22-0.26) was slowly added to the dry mix obtained in step (4), and a water reducing agent and cellulose ether were simultaneously added, and the mixture was stirred at 300rpm for 3 minutes to form a homogeneous slurry.

[0066] (6) Add basalt fiber and lithium polysilicate into the slurry of step (5) in batches, stir at low speed of 100 rpm for 2 minutes to avoid fiber breakage, and obtain the mixed material.

[0067] (7) Molding and curing: after the mixed material of step (6) is injected into a mold, it is vibrated to be compacted (frequency 50 Hz, time 30 s), and is covered with plastic film to prevent moisture evaporation; then, curing is performed, the first stage is demolding after curing at 20±2℃ and humidity ≥95% for 24 h; the second stage is steam curing at 40℃ for 48 h (temperature rising rate 10℃ / h), and then standard curing is performed for 28 days.

[0068] In step (6) above, the basalt fiber and lithium polysilicate are added in three batches, each with an interval of 30±5 seconds, and each with about 1 / 3 of the total amount, and are dispersed at low speed.

[0069] The silane coupling agent in the above preparation method steps is an amino silane coupling agent, and γ-aminopropyl triethoxysilane coupling agent (KH-550 is selected.

[0070] A control experiment 1 is performed, the formula is the same as that of example 1, and in the preparation method, the zirconium silicate, silicon carbide and tourmaline powder are not pretreated, and the preparation method (4)-(7) of example 1 is used to prepare a control sample A.

[0071] A control experiment 2 is performed, the formula is the same as that of example 1, and the preparation method (1), (2) and (3) of example 1 is used to pretreat the zirconium silicate, silicon carbide and tourmaline powder, then the preparation method (4) and (5) is used, then the basalt fiber and lithium polysilicate are added at one time without being added in batches, and then the preparation method (7) is used for molding and curing. The difference between the control experiment 2 and example 1 is that the basalt fiber and lithium polysilicate are added at one time, and a control sample B is prepared from the control experiment 2.

[0072] A control experiment 3 is performed, the formula does not contain zirconium silicate (ZrSiO4), tourmaline powder, silicon carbide and hollow glass beads, and the corresponding mass fractions are transferred to the main material Portland cement. Therefore, the control experiment 3 includes the following components with mass fractions: Portland cement: 71 parts; high-alumina cement: 7 parts; lithium polysilicate: 1.5 parts; basalt fiber: 3 parts; barite sand: 16 parts; water reducing agent: 1 part; cellulose ether: 0.5 parts. The preparation method used is the preparation method steps (4), (5), (6) and (7) of example 1, and a control sample C is prepared.

[0073] The infrared radiation cement-based material prepared in Example One was tested for 28-day compressive strength and flexural strength according to GB / T 17671-1999 “Cement mortar strength test method”; the far infrared emissivity and radiation power were tested according to GB / T 32494-2016 “Functional ceramic material far infrared radiation performance test method”, the test wavelength band was 8-14 μm, the test temperature was 25°C, the standard black body was used as a control, and no less than 5 points of each sample were measured and the average value was taken. The dynamic impact total energy consumption and bending toughness index were tested according to GB / T 31387-2015 “Fiber concrete bending toughness test method”. The apparent density was tested according to GB / T 5486-2008 “Method for testing density and porosity of concrete”. The slump / extension was tested according to GB / T 50080-2016 “Ordinary concrete mixture performance test method”. The 180D shrinkage rate was tested according to GB / T 50082-2009 “Ordinary concrete long-term performance and durability test method”. Table 1 is the performance results.

[0074] Table 1

[0075]

[0076] From the mechanical property and far infrared radiation performance tests of the control sample pieces prepared by the multiple sets of control experiments of Example One of the application, it can be seen from Table 1 that, for the mechanical property comparison, the infrared radiation cement-based material (full formula + functional filler pretreatment + three times of fiber addition) of Example One of the application has a 28D compressive strength of 98.5 MPa and a flexural strength of 21.3 MPa, which are higher than those of all the control sample pieces prepared in the control experiments, and the infrared emissivity and radiation power are 0.92 and 7.5 W / m 2 , respectively, which are higher than those of all the control sample pieces prepared in the control experiments, and the apparent density is as low as 3300 kg / m 3 . The control sample piece C prepared in Control Experiment 3 (without functional filler) has the lowest strength, with a 28D compressive strength of only 83.2 MPa, which is 13.5% lower than that of the application, indicating that zirconium silicate (ZrSiO4), tourmaline powder, and silicon carbide have a significant effect on the densification and bearing capacity of the matrix, and the infrared emissivity and radiation power of the control sample piece C are the lowest (0.7 and 4.9 W / m 2), indicating that zirconium silicate (ZrSiO4), tourmaline powder, and silicon carbide can significantly improve the infrared emissivity and radiant power of the cement-based material. The control sample A prepared by the control experiment 1 is not pretreated with zirconium silicate (ZrSiO4), tourmaline powder, and silicon carbide, and the mechanical properties are obviously lower than those of the present application, with the 28D compressive strength and flexural strength being 75.2 MPa and 16.5 MPa, respectively. Since zirconium silicate (ZrSiO4), tourmaline powder, and silicon carbide are not pretreated, the bonding force between them and the cement matrix is low, and thus the mechanical properties are low. In addition, the dispersion of zirconium silicate (ZrSiO4), tourmaline powder, and silicon carbide is uneven, and the activity is low, which causes the infrared emissivity and radiant power to decrease significantly, being 0.84 and 6.2 W / m 2 , respectively, which are 0.08 and 1.3 W / m 2 , respectively, lower than those of the present application. The control sample B prepared by the control experiment 2 is added with basalt fibers and polysilicate lithium at one time, with the 28D compressive strength being 88.0 MPa and the flexural strength being 18.7 MPa, which are lower than those of the present application. The main reason is that the uniform distribution of the fibers in the matrix is uneven due to the one-time addition of the fibers, which leads to low mechanical properties. The present application can significantly improve the dispersion of the fibers and the crack inhibition effect, improve the uniform distribution of the fibers in the matrix, enhance the crack inhibition effect, and thus enhance the flexural and compressive strengths. In addition, the infrared emissivity and radiant power of the control sample B are similar to those of the present application, and the infrared radiation performance changes little.

[0077] In addition, the bending toughness index of the present application is 35.2 J, which is higher than that of the control experiments. The bending toughness indexes of the control sample A prepared by the control experiment 1, the control sample B prepared by the control experiment 2, and the control sample C prepared by the control experiment 3 are 32.1 J, 29.8 J, and 20 J, respectively. The dynamic impact energy consumption of the present application is 4900 KJ / m 3 , which is higher than that of the control experiments. The dynamic impact energy consumptions of the control sample A prepared by the control experiment 1, the control sample B prepared by the control experiment 2, and the control sample C prepared by the control experiment 3 are 3750 KJ / m 3 , 3950 KJ / m 3 , and 3260 KJ / m 3 , respectively. The main reason is that the present application pretreats zirconium silicate (ZrSiO4), tourmaline powder, and silicon carbide and adds basalt fibers three times to reduce agglomeration and improve stress transfer efficiency. The slump / extension of the present application is similar to that of the control experiments. The addition of zirconium silicate (ZrSiO4), tourmaline powder, and silicon carbide and the three-time addition of basalt fibers and polysilicate lithium in the present application do not significantly reduce the construction fluidity. The present application introduces hollow glass microbeads, and the density is much lower than that of the control sample C. The apparent density of the present application is 3300 kg / m 3 , and the apparent density of the control sample C is 3800 kg / m3 The present application is advantageous for energy saving and light weight. For 180D shrinkage, the present application is significantly lower than the control experiment, indicating that the functional filler and fiber network synergistically inhibit the dry shrinkage cracking.

[0078] The performance advantage of the embodiment one of the present application is mainly because silicon carbide, tourmaline powder and zirconium silicate respectively have excellent far infrared emission ability, thermoelectric conversion performance and infrared wavelength matching characteristics, and the three synergistically can significantly improve the emissivity and radiation power, the silane coupling agent modified and nano TiO2 functionalized tourmaline powder can improve the surface activity of the filler and the interfacial bonding force with the cement matrix, reduce the interface defects, improve the infrared activity and mechanical properties; adding basalt fiber and polysilicate lithium three times can reduce the fiber agglomeration, improve the uniform distribution of the fiber and the matrix, and enhance the crack inhibition effect, thereby enhancing the bending and compressive strength, and hollow glass microspheres can adjust the density, further optimizing the thermal stability and energy saving performance of the material.

[0079] In the embodiment two of the present application, an infrared radiation cement-based material includes the following components in mass fraction:

[0080] Portland cement: 52 parts;

[0081] Hollow glass microspheres: 8 parts;

[0082] High alumina cement: 5 parts;

[0083] Zirconium silicate (ZrSiO4): 8 parts;

[0084] Polysilicate lithium: 2 parts;

[0085] Silicon carbide: 5 parts;

[0086] Tourmaline powder: 2 parts;

[0087] Basalt fiber: 5 parts;

[0088] Barite sand: 10 parts;

[0089] Water reducing agent: 2 parts;

[0090] Cellulose ether: 1 part.

[0091] The particle size of the zirconium silicate (ZrSiO4) is 5 μm, which is treated with a silane coupling agent.

[0092] The length of the basalt fiber is 12 mm, and the diameter is 20 μm.

[0093] The tourmaline powder is a magnesio-tourmaline with a particle size of 1 μm.

[0094] The particle size range of the hollow glass microspheres is 20 μm.

[0095] The barite sand has a BaSO4 content of 95% and a particle size of 100.

[0096] The lithium polysilicate has a modulus of 3.0 and a solid content of 30%.

[0097] The water reducing agent is a polycarboxylic acid water reducing agent.

[0098] The preparation method of the infrared radiation cement-based material in the above embodiment two comprises the following steps:

[0099] (1) Zirconium silicate (ZrSiO4) pretreatment: place the zirconium silicate in an oven and dry it at 130°C for 4 hours; take 1.0% of the silane coupling agent based on the mass of the zirconium silicate, add it to anhydrous ethanol or isopropanol, and stir until uniform to form a coupling agent solution; slowly add the dried zirconium silicate to the coupling agent solution and stir at room temperature for 1 hour to allow the coupling agent to fully react and bond with the surface of the zirconium silicate particles, forming a dense and stable organic-inorganic interface layer; then dry at 70°C for 11 hours and cool to room temperature to obtain pretreated zirconium silicate.

[0100] (2) Silicon carbide pretreatment: place the silicon carbide in an oven under an inert atmosphere, heat it to 600±10°C at a heating rate of 10±2°C / min, maintain the temperature for 1±0.2 hours, and then cool it to room temperature; mix the high-temperature treated silicon carbide with anhydrous ethanol at a mass ratio of 1:10, then add polyethylene glycol-2000 (PEG-2000), and the amount of PEG-2000 is 0.8% of the mass of the silicon carbide; stir for 30±5 minutes to obtain a slurry; vacuum dry the slurry at 80±5°C for 30 minutes, and pass it through a 400-mesh sieve to obtain pretreated silicon carbide.

[0101] (3) Pretreatment of tourmaline powder: place the tourmaline powder in an oven and dry it at 110°C for 2 hours to remove surface adsorbed water and impurities, and cool it to room temperature; disperse the dried tourmaline powder in an appropriate amount of deionized water, add a silane coupling agent, and stir at room temperature for 1 hour to allow the coupling agent to uniformly coat the surface of the tourmaline powder, forming a stable organic-inorganic bonding layer; add 0.5% of a nano-TiO2 ethanol suspension (with a TiO2 solid content of 5wt%) based on the mass of the tourmaline powder to the material after the silane coupling agent treatment, and continue stirring for 10±1 minutes to construct a composite interface layer with infrared response activity and synergistic radiation ability; then perform hot air drying and vacuum drying in sequence, i.e., first dry at 80±5°C for 30 minutes, and then dry under vacuum conditions of -0.08MPa for 30 minutes; after drying, pass the material through a 600-mesh vibrating sieve (with an amplitude control of 1.0±0.2mm) to obtain pretreated tourmaline powder with uniform particle size and stable interface structure.

[0102] (4) Dry mixing: Silicate cement, high alumina cement, barite sand, hollow glass microspheres are added into a mixer and mixed at 150 rpm for 5 minutes; pretreated zirconium silicate, pretreated silicon carbide, and pretreated tourmaline powder are added and mixed for another 3 minutes until uniform, to obtain dry mixture.

[0103] (5) Wet mixing: water (water-binder ratio 0.22-0.26) is slowly added into the dry mixture obtained in step (4), and water reducing agent and cellulose ether are synchronously added, and stirred at 300 rpm for 3 minutes to form a homogeneous slurry.

[0104] (6) Basalt fibers and lithium polysilicate are added into the slurry obtained in step (5) and stirred at a low speed of 100 rpm for 2 minutes to avoid fiber breakage, to obtain mixed material.

[0105] (7) Molding and curing: the mixed material of step (6) is injected into a mold and vibrated to compact (frequency 50 Hz, time 30 s), and covered with plastic film to prevent moisture evaporation; then cured, demolded after the first stage of curing at 20±2℃ and humidity ≥95% for 24 h; and then cured in steam at 40℃ for 48 h (temperature rising rate 10℃ / h), and then cured under standard conditions for 28 days.

[0106] In step (6) above, the basalt fibers and lithium polysilicate are added in three times, each time with an interval of 30±5 seconds, and each time with about 1 / 3 of the total amount, and stirred at a low speed for dispersion.

[0107] The silane coupling agent in the above preparation method is an epoxy silane coupling agent, which is γ-glycidoxypropyltrimethoxysilane coupling agent (KH-560).

[0108] Control experiment 4 is performed, with the same formula as in this example two, and in the preparation method, the zirconium silicate, silicon carbide, and tourmaline powder are not pretreated, and the preparation method (4)-(7) of this example two is used to prepare control sample D.

[0109] Control experiment 5 is performed, with the same formula as in this example two, and the preparation method (1), (2), and (3) of this example two is used to pretreat the zirconium silicate, silicon carbide, and tourmaline powder, and then the preparation method (4) and (5) is used, and then the basalt fibers and lithium polysilicate are added at one time without being added in multiple times, and then the preparation method (7) is used for molding and curing. The difference between control experiment 5 and this example two is that the basalt fibers and lithium polysilicate are added at one time, and control sample E is prepared from control experiment 5.

[0110] In the control experiment 6, zirconium silicate (ZrSiO4), tourmaline powder, silicon carbide, hollow glass beads are not included in the formula, and the corresponding mass fractions are transferred to the main material Portland cement. Therefore, the control experiment 6 includes the following components in the mass fraction: Portland cement: 75 parts; high-alumina cement: 5 parts; lithium polysilicate: 2 parts; basalt fiber: 5 parts; barite sand: 10 parts; water reducing agent: 2 parts; cellulose ether: 1 part. The preparation method used is the preparation method steps (4), (5), (6), (7) of the second embodiment, and the control sample F is prepared.

[0111] The infrared radiation cement-based materials prepared in the second embodiment are tested for 28-day compressive strength and flexural strength according to GB / T 17671-1999 "Cement mortar strength test method"; the far-infrared emissivity and radiation power are tested according to GB / T 32494-2016 "Functional ceramic material far-infrared radiation performance test method", the test wavelength band is 8-14 μm, the test temperature is 25℃, the standard black body is used as a control, not less than 5 points of each sample are measured and the average value is taken. The dynamic impact total energy consumption and bending toughness index are tested according to GB / T 31387-2015 "Fiber concrete bending toughness test method". The apparent density is tested according to GB / T 5486-2008 "Method for testing density and porosity of concrete". The slump / extension is tested according to GB / T 50080-2016 "Test method for performance of ordinary concrete mixture". The 180D shrinkage rate is tested according to GB / T 50082-2009 "Test method for long-term performance and durability of ordinary concrete". Table 2 shows the performance results.

[0112] Table 2

[0113]

[0114] From the mechanical property and far-infrared radiation performance tests of the control samples prepared by the second embodiment and multiple sets of control experiments, it can be seen from Table 2 that, for the mechanical property comparison of the infrared radiation cement-based material of the second embodiment, the 28D compressive strength is 95.5 MPa, and the flexural strength is 19.3 MPa, both of which are higher than those of all the control samples prepared in the control experiments, and the infrared emissivity and radiation power are 0.90 and 7.6 / m 2 which are higher than those of all the control samples prepared in the control experiments, and the apparent density is as low as 3400 kg / m 3. The control sample F prepared in the control experiment 6 has the lowest strength, with the 28D compressive strength of only 80.1 MPa and the bending strength of 17.0 MPa, which are lower than those of the second embodiment of the present application, mainly because the zirconium silicate (ZrSiO4), tourmaline powder and silicon carbide can significantly improve the density and bearing capacity of the cement matrix. The control sample F has the lowest infrared emissivity and radiation power (0.67 and 4.5 W / m 2 , respectively), mainly because the zirconium silicate (ZrSiO4), tourmaline powder and silicon carbide can significantly improve the infrared emissivity and radiation power of the cement matrix. The control sample D prepared in the control experiment 4 is not pre-processed with the zirconium silicate (ZrSiO4), tourmaline powder and silicon carbide, and has lower mechanical properties than the second embodiment of the present application, with the 28D compressive strength and bending strength of 74.1 MPa and 15.5 MPa, respectively. Since the zirconium silicate (ZrSiO4), tourmaline powder and silicon carbide are not pre-processed, the binding force between them and the cement matrix is low, resulting in low mechanical properties. In addition, the zirconium silicate (ZrSiO4), tourmaline powder and silicon carbide are not uniformly dispersed, and have low activity, which significantly reduces the infrared emissivity and radiation power to 0.80 and 6.0 W / m 2 , respectively. The control sample E prepared in the control experiment 5 is added with basalt fibers and lithium polysilicate at one time, with the 28D compressive strength of 86.0 MPa and the bending strength of 18.73 MPa, which are lower than those of the second embodiment of the present application. This is mainly because the fibers are not uniformly distributed in the matrix, resulting in low mechanical properties. The third embodiment of the present application can significantly improve the dispersion of fibers and the crack suppression effect, improve the uniform distribution of fibers in the matrix, and enhance the crack suppression effect, thereby enhancing the bending and compressive strengths. In addition, the infrared emissivity and radiation power of the control sample E are similar to those of the first embodiment of the present application, and the infrared radiation performance changes little.

[0115] In addition, the bending toughness index of the second embodiment of the present application is 37.2 J, which is higher than that of the control experiment 4, the control experiment 5 and the control experiment 6. The bending toughness indexes of the control sample D prepared in the control experiment 4, the control sample E prepared in the control experiment 5 and the control sample F prepared in the control experiment 6 are 31.1 J, 27.8 J and 23.4 J, respectively. The dynamic impact energy consumption of the second embodiment of the present application is 4800 KJ / m 3 , which is higher than that of the control experiment 4, the control experiment 5 and the control experiment 6. The dynamic impact energy consumptions of the control sample D prepared in the control experiment 4, the control sample E prepared in the control experiment 5 and the control sample F prepared in the control experiment 6 are 3960 KJ / m 3 , 3980 KJ / m 3 , and 3160 KJ / m 3, mainly because the present application for zirconium silicate (ZrSiO4), tourmaline powder, silicon carbide pretreatment while adding basalt fiber three times to reduce the agglomeration, improve the stress transfer efficiency makes the bending toughness index and dynamic impact energy consumption is higher. The slump / spread of the second embodiment of the present application is similar to that of the control experiment, and the addition of zirconium silicate (ZrSiO4), tourmaline powder, silicon carbide and optimized fiber adding process in the present application does not significantly reduce the construction fluidity. The present application has a much lower density than the control sample F due to the introduction of hollow glass microspheres. The apparent density of the second embodiment is 3400kg / m 3 The apparent density of the control sample F is 3900kg / m 3 The present application is beneficial to energy saving and lightweight. For 180D shrinkage, the present application is significantly lower than the control experiment 6 to obtain the control sample F, and the 180D shrinkage of the second embodiment is 430x10 -6 The 180D shrinkage of the control sample F is 510x10 -6 , which shows that the network of silicon carbide, tourmaline powder, zirconium silicate, hollow glass beads and basalt fiber synergistically inhibits the dry shrinkage cracking.

[0116] In summary, the infrared radiation cement-based material of the present application is significantly superior to each control group in terms of mechanical properties and far infrared radiation performance, and the effectiveness of the pretreatment of silicon carbide, tourmaline powder and zirconium silicate and the optimization of the three-time fiber adding process are verified by comparison experiments, which has significant comprehensive performance advantages and industrial application value.

Claims

1. An infrared radiation cement-based material, characterized by: The raw materials include the following components in parts by mass: Portland cement: 45-55 parts; Hollow glass microspheres: 5-10 parts; High alumina cement: 5-10 parts; Zirconium silicate (ZrSiO4): 8-12 parts; Lithium polysilicate: 1-2 parts; Silicon carbide: 5-8 parts; Tourmaline powder: 2-4 parts; Basalt fiber: 2-5 parts; Barite sand: 10-20 parts; Water reducing agent: 1-2 parts; Cellulose ether: 0.5-1 part.

2. The infrared radiation cement-based material according to claim 1, characterized in that: The particle size of the zirconium silicate (ZrSiO4) is 0.5-5 μm.

3. The infrared radiation cement-based material according to claim 1, characterized in that: The basalt fiber has a length of 12-18 mm and a diameter of 15-20 μm.

4. The infrared radiation cement-based material according to claim 1, characterized in that: The tourmaline powder is magnesium tourmaline with a particle size not greater than 3 μm.

5. The infrared radiation cement-based material according to claim 1, characterized in that: The particle size of the hollow glass microspheres ranges from 10 to 100 μm.

6. The infrared radiation cement-based material according to claim 1, characterized in that: The BaSO4 content in the barite sand is ≥95%, and the particle size of the barite sand is 100-200 μm.

7. The infrared radiation cement-based material according to claim 1, characterized in that: The modulus of the lithium polysilicate is 2.5-3.5, and the solid content is 20-30%.

8. The infrared radiation cement-based material according to claim 1, characterized in that: The water reducer is a polycarboxylate water reducer.

9. The method for preparing an infrared radiation cement-based material according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Pretreatment of zirconium silicate (ZrSiO4): Place the zirconium silicate in an oven and dry it at 120-150°C for 2-4 hours; add silane coupling agent at a rate of 0.5-2.0% of the mass of the zirconium silicate to anhydrous ethanol or isopropanol, and stir evenly to form a coupling agent solution; slowly add the dried zirconium silicate to the coupling agent solution, stir at room temperature for 1 hour, then dry it at 60-80°C for 10-12 hours and cool it to room temperature to obtain pretreated zirconium silicate; (2) Pretreatment of silicon carbide: Place silicon carbide in an inert atmosphere oven, heat to 600±10°C at a heating rate of 10±2°C / min, keep warm for 1±0.2 hours, and cool to room temperature; mix the high-temperature treated silicon carbide with anhydrous ethanol at a mass ratio of 1:10, then add polyethylene glycol-2000 (PEG-2000), the amount of polyethylene glycol-2000 (PEG-2000) is 0.5-1.0% of the mass of silicon carbide, and stir for 30±5 minutes to obtain a slurry; vacuum dry the slurry at 80±5°C for 30 minutes, and pass it through a 400-mesh sieve to obtain pretreated silicon carbide; (3) Pretreatment of tourmaline powder: Place the tourmaline powder in an oven, dry it at 100-120°C for 2 hours, and cool it to room temperature; disperse the dried tourmaline powder in deionized water, add a silane coupling agent, the amount of the silane coupling agent is 0.5-2.0% of the mass of the tourmaline powder, and stir at room temperature for 1 hour; add a nano-TiO2 ethanol suspension with a mass of 0.3-0.8% of the tourmaline powder to the material treated with the silane coupling agent, and continue stirring for 10±1 minutes; then perform hot air drying and vacuum drying in sequence, that is, first hot air drying at 80±5°C for 30 minutes, and then drying at -0.08MPa vacuum for 30 minutes; after drying, pass through a 600-mesh vibrating sieve (amplitude controlled at 1.0±0.2mm) to obtain pretreated tourmaline powder; (4) Dry mixing: Portland cement, high alumina cement, barite sand, and hollow glass microspheres were added to a blender and mixed at 150 rpm for 5 minutes; then zirconium silicate, pretreated silicon carbide, and pretreated tourmaline powder were added and mixed for another 3 minutes until uniform to obtain a dry blend; (5) Wet mixing: slowly add water (water-to-binder ratio 0.22-0.26) to the dry mix obtained in step (4), simultaneously add a water reducer and cellulose ether, and stir at 300 rpm for 3 minutes to form a homogeneous slurry; (6) adding basalt fiber and lithium polysilicate to the homogeneous slurry obtained in step (5), stirring at a low speed of 100 rpm for 2 minutes to obtain a mixed material; (7) Molding and curing: The mixed material of step (6) is injected into the mold and vibrated to compact it (frequency 50 Hz, time 30 s), and then covered with a plastic film; then curing is carried out. The first stage is curing at 20±2°C and humidity ≥95% for 24 hours before demolding; the second stage is steam curing at 40°C for 48 hours (heating rate 10°C / h), and then standard curing is carried out for up to 28 days.

10. The method for preparing an infrared radiation cement-based material according to claim 9, characterized in that: The silane coupling agent in the steps is an aminosilane coupling agent or an epoxysilane coupling agent; In the step (6), the basalt fiber and lithium polysilicate are added to the homogenized slurry three times, each time with an interval of 30±5 seconds, and the amount added each time is 1 / 3 of the number of basalt fiber and lithium polysilicate.

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