Thermal insulation transparent concrete and preparation method thereof

Abstract

The application discloses a kind of heat preservation and insulation transparent concrete, including transparent concrete matrix and heat preservation and insulation coating, comprising by mass percentage: epoxy resin 15~25%, curing agent 5~10%, glass sand 55~70%, silane coupling agent 0.1~5%, silicon source 2~5%, alkaline solvent 2~5%, heat insulation semiconductor particles 1~10%; Its preparation method is: glass sand is entered with epoxy resin, curing agent and is cured to obtain matrix, silicon source is added in alkaline solvent and is stirred evenly with silane coupling agent, heat insulation semiconductor particles, then is sprayed to the surface of matrix and sintered solidification.The concrete of the application utilizes the reaction of silane coupling agent in coating with the hydrolysis product silicon dioxide of silicon source, heat insulation semiconductor particles and epoxy resin in matrix to form chemical bond combination, increases the bonding strength of coating and matrix, ensures that transparent concrete has excellent light transmittance and heat preservation and insulation characteristics, and is suitable for building material field.

Description

Technical Field

[0001] The invention belongs to the field of civil engineering materials, and particularly relates to thermal insulation transparent concrete and a preparation method thereof. Background Art

[0002] Transparent concrete is widely used in architecture and interior design, particularly in industrial developments and low-rise buildings. It can be used as the primary material for load-bearing walls, for interior and exterior cladding of building surfaces (including floors), to form partition walls, and to construct interior partitions. Transparent concrete is also used to create small structures such as streetlight shades, benches, and fountains, as well as as a surface treatment for countertops, stairwells, and restroom furniture. Current methods for producing transparent concrete typically involve pouring cement or asphalt concrete around a fixed optical fiber to create the light-guiding concrete.

[0003] The light transmittance of concrete prepared using the above method is significantly limited. Numerous research teams have conducted studies to improve the light transmittance of transparent concrete. Epoxy resin is a class of thermosetting polymer synthetic materials with excellent properties. Its cured products exhibit excellent adhesion, high mechanical strength, low shrinkage, and chemical resistance, making them a material with excellent overall performance. Its cured and modified products are widely used in civil engineering and construction, replacing many traditional materials.

[0004] By replacing traditional cement-based binders with epoxy resin and using glass sand instead of sand and gravel aggregates, transparent concrete with high light transmittance can be produced. However, this technology is not yet mature and has many shortcomings: for example, epoxy resin itself does not have good thermal insulation properties, and transparent concrete has poor thermal insulation performance when used as exterior walls. Some researchers have prepared epoxy composite materials with anisotropic structures by adding hexagonal boron nitride (h-BN) as a filler to epoxy resin, but the addition of these materials reduces the light transmittance of the concrete. Therefore, the existence of a transparent concrete with good thermal insulation properties and high light transmittance is very necessary. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of the above-mentioned prior art and provide a thermally insulating transparent concrete. In the thermally insulating transparent concrete, a silane coupling agent is used in the thermally insulating coating to react with silicon dioxide, a product of silicon source hydrolysis, thermally insulating semiconductor particles, and the epoxy resin in the transparent concrete matrix, forming chemical bonds. This allows the thermally insulating coating to adhere tightly to the surface of the transparent concrete matrix, ensuring that the transparent concrete has good light transmittance while also exhibiting excellent thermal insulation properties. This solves the existing problem of transparent concrete having difficulty achieving both high light transmittance and thermal insulation properties.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a thermal insulation transparent concrete, including a transparent concrete base and a thermal insulation coating sprayed and sintered and cured on the transparent concrete base, wherein the thermal insulation transparent concrete contains the following components by mass percentage: 15% to 25% epoxy resin, 5% to 10% curing agent, 55% to 70% glass sand, 0.1% to 5% silane coupling agent, 2% to 5% silicon source, 2% to 5% alkaline solvent, and 1% to 10% thermal insulation semiconductor particles.

[0007] The thermal insulation transparent concrete of the present invention has a double-layer structure of a transparent concrete base and a thermal insulation coating sprayed and sintered and cured on the transparent concrete base. The thermal insulation transparent concrete is defined as containing epoxy resin, curing agent, glass sand, silane coupling agent, silicon source, alkaline solvent, and thermal insulation semiconductor particles. The epoxy resin, curing agent, and glass sand are components of the transparent concrete base, and the silane coupling agent, silicon source, alkaline solvent, and thermal insulation semiconductor particles are components of the thermal insulation coating. The silicon source in the thermal insulation coating undergoes a hydrolysis reaction in an alkaline solvent, breaking the silicon-oxygen bond to generate silicic acid (Si(OH)4) and methanol (CH3OH). The corresponding reaction mechanism is shown in the following formula (1):

[0008] Si(OCH3)4+4H2O→Si(OH)4+4CH3OH (1)

[0009] Si(OH)4 will further condense to form a three-dimensional network structure of silica (SiO2) gel or particles. The corresponding reaction mechanism is shown in the following formula (2):

[0010] Si(OH)4→SiO2+2H2O(2)

[0011] At the same time, the molecular structure of the silane coupling agent in the thermal insulation coating is generally: Y-Si-(OR)3 (OR—hydrolyzable siloxane group; Y—organic functional group, which can react with the resin), the siloxane group (-OR) hydrolyzes to generate silanol (Si(OH)3, the functional group is -Si-OH, releasing alcohol (ROH), the corresponding reaction mechanism is shown in the following formula (3):

[0012] Si(OR)3+3H2O→Si(OH)3+3ROH(3)

[0013] Silanol (-Si-OH) undergoes dehydration condensation with hydroxyl groups (-OH) on the surface of inorganic materials (silicon oxide, semiconductor particles) to form Si-O-Si covalent bonds, fixing silane to the surface of the inorganic material. The corresponding reaction mechanism is shown in the following formula (4):

[0014] Inorganic -OH + Si(OH)3 → Inorganic -O-Si- + H2O (4)

[0015] The other end with the organic functional group Y reacts with the epoxy resin in the transparent concrete matrix to form an "inorganic-O-Si-epoxy resin" structure, thereby tightly attaching the thermal insulation coating to the surface of the transparent concrete matrix. Figure 1 As shown in the figure, the silane coupling agent forms a chemical bond at the interface between the polymer and the silicon dioxide generated by the silicon source, significantly improving the reinforcing properties of the silicon dioxide. It acts as a "molecular bridge" to connect the two materials with vastly different properties, thereby increasing the bonding strength between the thermal insulation coating and the transparent concrete substrate, giving the transparent concrete excellent thermal insulation properties without affecting its light transmittance.

[0016] The above-mentioned thermal insulation transparent concrete contains the following components by mass percentage: 15% to 20% epoxy resin, 5% to 7% curing agent, 55% to 60% glass sand, 0.5% to 1% silane coupling agent, 2% to 5% silicon source, 2% to 4% alkaline solvent, and 3% to 7% thermal insulation semiconductor particles.

[0017] In the above-mentioned thermal insulation transparent concrete, the epoxy resin is a mixture of bisphenol A glycidyl ether epoxy resin and a mixed epoxy resin having both alicyclic epoxy groups and glycidyl ester groups in a mass ratio of 1:2-4.

[0018] In the above-mentioned thermal insulation transparent concrete, the curing agent is composed of a modified aromatic amine curing agent and dibenzoyl peroxide in a mass ratio of 1:1 to 3. This curing agent composition ensures high strength of the epoxy resin after curing and good adhesion to glass sand.

[0019] In the aforementioned thermal insulation transparent concrete, the glass sand is composed of glass particles with particle sizes of 0.5 mm to 1 mm and 1 mm to 2 mm in a mass ratio of 1:2 to 5. The present invention utilizes two different sized glass particles to form the glass sand. The large-sized glass particles serve as a supporting skeleton in the resin curing system of the transparent concrete matrix, while the small-sized glass particles fill the tiny gaps in the resin curing system, making the resin curing more dense. The synergistic effect of the two different sized glass particles makes the interior of the transparent concrete matrix more dense, thereby having higher mechanical strength.

[0020] In the aforementioned thermal insulation transparent concrete, the silane coupling agent is selected from γ-methacryloxypropyltrimethoxysilane (KH570) and silane coupling agents with the same structure. KH570 contains a methacryloxy group (CH2=C(CH3)COO-), which can copolymerize with unsaturated double bonds in various organic polymers or, under peroxide initiation, undergo addition reactions with unsaturated double bonds in plastics, rubbers, or resins, thereby achieving crosslinking and curing. "Same structure" refers to silane coupling agents containing methacryloxypropyltrimethoxysilane, such as A-174 (Union Carbide Corporation), KBM-503 (Shin-Etsu Chemical Co., Ltd.), and Z-6030 (Dow Corning Corporation). All three silane coupling agents are chemically named 3-(methacryloxy)propyltrimethoxysilane.

[0021] In the above-mentioned thermal insulation transparent concrete, the silicon source is one or more of methyl orthosilicate, ethyl orthosilicate, methyltrimethoxysilane and methyltriethoxysilane.

[0022] In the above-mentioned thermal insulation transparent concrete, the alkaline solvent is one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia water and sodium carbonate solution.

[0023] In the above-mentioned thermal insulation transparent concrete, the thermal insulation semiconductor particles are one or more of expanded perlite powder, expanded vermiculite, ceramic powder, and alkali borosilicate glass powder with thermal insulation function.

[0024] At the same time, the present invention also discloses a method for preparing the thermal insulation transparent concrete as described above, the method comprising the following steps:

[0025] Step 1: Weigh glass sand and stir for 3 to 5 minutes, then stir and mix with epoxy resin and curing agent using a vacuum degassing mixer to obtain a matrix mixed slurry; the speed of the vacuum degassing mixer is 1000 rpm to 1500 rpm, and the stirring time is 20 to 30 minutes;

[0026] Step 2: Pour the matrix mixed slurry obtained in step 1 into a mold and smooth the surface. After curing at room temperature for 5 days, remove the mold to obtain a transparent concrete matrix;

[0027] Step 3: Add the silicon source to the alkaline solvent and stir to dissolve, then add the silane coupling agent and stir for 5 min to 40 min, then add the heat-insulating semiconductor particles and stir for 10 min to 200 min until uniform, to obtain a coating mixed slurry;

[0028] Step 4: Clean and remove static electricity from the surface of the transparent concrete substrate in step 2, then spray the coating mixed slurry obtained in step 3, sinter and solidify it, and form a thermal insulation layer after cooling to obtain thermal insulation transparent concrete; the spraying thickness of the coating mixed slurry is 150μm~1000μm, the sintering and solidification temperature is 100℃~180℃, and the time is 2min~10min.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] 1. In the thermal insulation transparent concrete of the present invention, by limiting the components of the transparent concrete substrate and the thermal insulation coating, a silane coupling agent is used to react with the silicon source hydrolysis product silica, the thermal insulation semiconductor particles, and the epoxy resin in the transparent concrete substrate to form chemical bonds, thereby forming a dense thermal insulation coating that is tightly attached to the surface of the transparent concrete substrate, thereby increasing the bonding strength between the thermal insulation coating and the transparent concrete substrate, ensuring that the transparent concrete has good light transmittance while also having excellent thermal insulation properties.

[0031] 2. The silicon dioxide, a hydrolysis product of the silicon source, and the heat-insulating semiconductor particles in the thermal insulation coating of the present invention work synergistically to provide heat insulation on the surface of the transparent concrete, further ensuring that the transparent concrete has excellent heat-insulating properties.

[0032] 3. The addition of alkaline solvent to the thermal insulation coating of the present invention makes it easier for the silicon source component to hydrolyze, thereby generating more silicon dioxide, further improving the thermal insulation performance of the transparent concrete.

[0033] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the action mechanism of the silane coupling agent in the thermal insulation coating of the thermal insulation transparent concrete of the present invention. DETAILED DESCRIPTION

[0035] Example 1

[0036] The thermal insulation transparent concrete of this embodiment includes a transparent concrete base and a thermal insulation coating sprayed and sintered and cured on the transparent concrete base. The thermal insulation transparent concrete contains the following components by mass percentage: 15% epoxy resin, 5% curing agent, 70% glass sand, 0.5% silane coupling agent, 2% silicon source, 3.5% alkaline solvent, and 4% thermal insulation semiconductor particles.

[0037] The epoxy resin is a mixture of bisphenol A glycidyl ether epoxy resin and a mixed epoxy resin having both alicyclic epoxy groups and glycidyl ester groups in a mass ratio of 1:4;

[0038] The curing agent is composed of a modified aromatic amine curing agent (HG-3001 model, produced by Guangzhou Shenggu Chemical Co., Ltd.) and dibenzoyl peroxide in a mass ratio of 1:3;

[0039] The glass sand is composed of glass particles with particle sizes of 0.5mm-1mm and 1mm-2mm in a mass ratio of 1:5;

[0040] The silane coupling agent is γ-methacryloxypropyltrimethoxysilane, namely KH570;

[0041] The silicon source is methyl orthosilicate;

[0042] The alkaline solvent is a sodium hydroxide solution with a pH of 9;

[0043] The heat-insulating semiconductor particles are expanded perlite powder with heat-insulating function.

[0044] The preparation method of the thermal insulation transparent concrete of this embodiment comprises the following steps:

[0045] Step 1: Weigh glass sand and stir for 4 minutes, then stir and mix with epoxy resin and curing agent using a vacuum degassing mixer to obtain a matrix mixed slurry; the speed of the vacuum degassing mixer is 1200 r / min, and the stirring time is 20 minutes;

[0046] Step 2: Pour the matrix mixed slurry obtained in step 1 into a mold and smooth the surface. After curing at room temperature for 5 days, remove the mold to obtain a transparent concrete matrix;

[0047] Step 3: Add the silicon source to the alkaline solvent and stir to dissolve, then add the silane coupling agent and stir for 20 minutes, then add the heat-insulating semiconductor particles and stir for 50 minutes until uniform, to obtain a coating mixed slurry;

[0048] Step 4: Clean and remove static electricity from the surface of the transparent concrete substrate in step 2, then spray the coating mixed slurry obtained in step 3, sinter and solidify it, and form a thermal insulation layer after cooling to obtain thermal insulation transparent concrete; the spraying thickness of the coating mixed slurry is 200 μm, the sintering and solidification temperature is 170°C, and the time is 5 minutes.

[0049] The silane coupling agent in this embodiment can also be selected from silane coupling agent products having the same structure as γ-methacryloxypropyltrimethoxysilane; the silicon source can also be one or more of methyl orthosilicate, ethyl orthosilicate, methyltrimethoxysilane and methyltriethoxysilane other than methyl orthosilicate; the alkaline solvent can also be one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia water and sodium carbonate solution other than sodium hydroxide solution; the thermal insulating semiconductor particles can also be one or more of expandable perlite powder, expandable vermiculite, ceramic powder and alkali borosilicate glass powder other than expandable perlite powder with thermal insulation function.

[0050] Example 2

[0051] The difference between this embodiment and embodiment 1 is that the thermal insulation transparent concrete contains the following components by mass percentage: 25% epoxy resin, 10% curing agent, 59% glass sand, 1% silane coupling agent, 2% silicon source, 2% alkaline solvent, and 1% thermal insulation semiconductor particles.

[0052] The epoxy resin is a mixture of bisphenol A glycidyl ether epoxy resin and a mixed epoxy resin having both alicyclic epoxy groups and glycidyl ester groups in a mass ratio of 1:2.

[0053] Example 3

[0054] The difference between this embodiment and embodiment 1 is that the thermal insulation transparent concrete contains the following components by mass percentage: 15% epoxy resin, 6% curing agent, 60% glass sand, 0.1% silane coupling agent, 5% silicon source, 4.9% alkaline solvent, and 9% thermal insulation semiconductor particles.

[0055] The curing agent is composed of a modified aromatic amine curing agent (HG-3001 model, produced by Guangzhou Shenggu Chemical Co., Ltd.) and dibenzoyl peroxide in a mass ratio of 1:1.

[0056] Example 4

[0057] The difference between this embodiment and embodiment 1 is that the thermal insulation transparent concrete contains the following components by mass percentage: 15% epoxy resin, 5% curing agent, 67% glass sand, 5% silane coupling agent, 2% silicon source, 5% alkaline solvent, and 1% thermal insulation semiconductor particles.

[0058] The glass sand is composed of glass particles with particle sizes of 0.5mm-1mm and 1mm-2mm in a mass ratio of 1:2.

[0059] Example 5

[0060] The difference between this embodiment and embodiment 1 is that the thermal insulation transparent concrete contains the following components by mass percentage: 15% epoxy resin, 7% curing agent, 55% glass sand, 5% silane coupling agent, 5% silicon source, 3% alkaline solvent, and 10% thermal insulation semiconductor particles.

[0061] The glass sand is composed of glass particles with particle sizes of 0.5mm-1mm and 1mm-2mm in a mass ratio of 1:3.

[0062] The thermal insulation transparent concrete prepared in Examples 1 to 5 of the present invention was tested for compressive strength and flexural strength according to GB / T50081-2019 "Standard for Test Methods for Mechanical Properties of Ordinary Concrete". The compressive strength specimen was a 100 mm × 100 mm × 100 mm cube, and the flexural strength specimen was a 100 mm × 100 mm × 400 mm prism; the thermal conductivity was tested according to the ASTM E 1530 method; and the transmittance was tested in an open dark box using a solar tester: transmittance = (irradiance when no specimen is placed - irradiance when the specimen is placed - irradiance when the opening is completely shielded) / irradiance when no specimen is placed. The results are shown in Table 1 below.

[0063] Table 1

[0064]

[0065] As can be seen from Table 1, the 28d compressive strength of the thermal insulation transparent concrete prepared in Examples 1 to 5 of the present invention all reached above 90 MPa, among which the compressive strength of the thermal insulation transparent concrete prepared in Example 4 reached 110 MPa, reaching the level of high-strength concrete. The 28d flexural strength was around 30 MPa, which is relatively high. The light transmittance was 40% to 45%, which is good when used in building walls. At the same time, the thermal insulation transparent concrete prepared in Examples 1 to 5 all had a thermal conductivity of around 0.10, which is comparable to the thermal conductivity of aerated concrete and lightweight blocks in common walls, and is a material with good thermal insulation performance.

[0066] In summary, the thermal insulation transparent concrete of the present invention has good load-bearing, thermal insulation and appearance effects as a building wall material.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A thermal insulation transparent concrete, characterized in that: The thermal insulation transparent concrete comprises a transparent concrete base and a thermal insulation coating sprayed and sintered and cured on the transparent concrete base. The thermal insulation transparent concrete comprises the following components by mass percentage: 15% to 25% epoxy resin, 5% to 10% curing agent, 55% to 70% glass sand, 0.1% to 5% silane coupling agent, 2% to 5% silicon source, 2% to 5% alkaline solvent, and 1% to 10% thermal insulation semiconductor particles. The preparation method of the thermal insulation transparent concrete comprises the following steps: Step 1: Weigh glass sand and stir for 3 to 5 minutes, then stir and mix with epoxy resin and curing agent using a vacuum degassing mixer to obtain a matrix mixed slurry; the speed of the vacuum degassing mixer is 1000 rpm to 1500 rpm, and the stirring time is 20 to 30 minutes; Step 2: Pour the matrix mixed slurry obtained in step 1 into a mold and smooth the surface. After curing at room temperature for 5 days, remove the mold to obtain a transparent concrete matrix; Step 3: Add the silicon source to the alkaline solvent and stir to dissolve, then add the silane coupling agent and stir for 5 min to 40 min, then add the heat-insulating semiconductor particles and stir for 10 min to 200 min until uniform, to obtain a coating mixed slurry; Step 4: Clean and remove static electricity from the surface of the transparent concrete substrate in step 2, then spray the coating mixed slurry obtained in step 3, sinter and solidify it, and form a thermal insulation layer after cooling to obtain thermal insulation transparent concrete; the spraying thickness of the coating mixed slurry is 150μm~1000μm, the sintering and solidification temperature is 100℃~180℃, and the time is 2min~10min.

2. The thermal insulation transparent concrete according to claim 1, characterized in that: The thermal insulation transparent concrete contains the following components by mass percentage: 15% to 20% epoxy resin, 5% to 7% curing agent, 55% to 60% glass sand, 0.5% to 1% silane coupling agent, 2% to 5% silicon source, 2% to 4% alkaline solvent, and 3% to 7% thermal insulation semiconductor particles.

3. The thermal insulation transparent concrete according to claim 1, characterized in that: The epoxy resin is a mixture of a bisphenol A glycidyl ether epoxy resin and a mixed epoxy resin having both alicyclic epoxy groups and glycidyl ester groups in a mass ratio of 1:2-4.

4. The thermal insulation transparent concrete according to claim 1, characterized in that: The curing agent is composed of a modified aromatic amine curing agent and dibenzoyl peroxide in a mass ratio of 1:1-3.

5. The thermal insulation transparent concrete according to claim 1, characterized in that: The glass sand is composed of glass particles with particle sizes of 0.5mm-1mm and 1mm-2mm in a mass ratio of 1:2-5.

6. The thermal insulation transparent concrete according to claim 1, characterized in that: The silane coupling agent is selected from gamma-methacryloxypropyltrimethoxysilane (KH570) and silane coupling agent products with the same structure.

7. The thermal insulation transparent concrete according to claim 1, characterized in that: The silicon source is one or more of methyl orthosilicate, ethyl orthosilicate, methyltrimethoxysilane and methyltriethoxysilane.

8. The thermal insulation transparent concrete according to claim 1, characterized in that: The alkaline solvent is one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia water and sodium carbonate solution.

9. The thermal insulation transparent concrete according to claim 1, characterized in that: The heat-insulating semiconductor particles are one or more of expanded pearlite powder, expanded vermiculite, ceramic powder, and alkali borosilicate glass powder with heat-insulating function.

Images