A modified geopolymer mortar and its use on structural elements

Abstract

The application provides a modified geopolymer mortar and application thereof on structural members. The modified geopolymer mortar can be applied on the outer surface of the structural members and comprises the following raw materials in parts by weight: sodium hydroxide 31-35 parts, water glass solution 200-210 parts, blast furnace slag 1450-1550 parts, fly ash 1450-1550 parts, silica fume 90-450 parts, natural river sand 4450-4550 parts, polypropylene fiber 5-8 parts, hollow glass microsphere 90-400 parts, and water 1110-1320 parts. The equivalent thermal conductivity λ of the modified geopolymer mortar and the thickness di thereof should satisfy the following relationship: λ=-1.3613di+0.4684. The modified geopolymer mortar can improve the fire resistance limit of the structural members to 2-4 hours or more and has high strength.

Description

Technical Field

[0001] This invention relates to the field of fire protection and reinforcement technology for structural components, and more specifically, to a modified geopolymer mortar and its application in structural components. Background Technology

[0002] Buildings are vital carriers of human life and production activities, and their safety is directly related to the safety of people's lives and property. Among various threats to building safety, fire stands out for its suddenness, destructive power, and unpredictability. Fire not only causes direct damage through high temperatures and open flames, but more seriously, the damage it inflicts on the building's load-bearing structure can lead to severe damage that is difficult to repair, or even loss of stability, causing partial or complete collapse.

[0003] Currently, commonly used fire protection technologies for building structures mainly include methods such as wrapping with fire-resistant panels, flexible roofing membranes, cast-in-place concrete, and spraying fire-retardant coatings. However, these methods have limitations such as complex construction, insufficient durability, environmental pollution, or excessive weight. Furthermore, existing concrete structures often require reinforcement by increasing the cross-section due to changes in function, degradation of load-bearing capacity, and quality defects, which typically necessitates re-forming and re-casting concrete, a cumbersome process. Summary of the Invention

[0004] This invention discloses a modified geopolymer mortar and its application in structural components to solve the above-mentioned problems.

[0005] The present invention adopts the following solution:

[0006] This application provides a modified geopolymer mortar that can be applied to the outer surface of structural components; the modified geopolymer mortar comprises the following raw materials by weight: 31-35 parts sodium hydroxide, 200-210 parts water glass solution, 1450-1550 parts blast furnace slag, 1450-1550 parts fly ash, 90-450 parts silica fume, 4450-4550 parts natural river sand, 5-8 parts polypropylene fiber, 90-400 parts hollow glass microspheres, and 1110-1320 parts water.

[0007] The equivalent thermal conductivity of the modified geopolymer mortar is... [W / (m·K)] and its thickness (m) should satisfy the following relationship:

[0008]

[0009] Among them, the thickness of modified geopolymer mortar Its applicable range is 0.0015m-0.060m.

[0010] Further, the water glass solution has a Baumé degree of 50, a modulus of 2.25, and a sodium hydroxide mass percentage of not less than 95%; when diluting 100 parts of the water glass solution, the amount of sodium hydroxide added is... Its purity The relationship is as follows:

[0011] .

[0012] Furthermore, the natural river sand has a particle size of 0.1-0.5 mm, the polypropylene fiber has a length of 6-19 mm, and the hollow glass microspheres have a particle size of 10-250 μm and a wall thickness of 1-2 μm.

[0013] Furthermore, after the modified geopolymer mortar is applied to the outer surface of the structural member to form a protective layer, it needs to be sprayed with water for curing, and the temperature difference between the curing water and the surface of the protective layer should not exceed 15°C.

[0014] This application also provides the application of the modified geopolymer mortar in structural components for fire protection and / or reinforcement of the structural components.

[0015] Furthermore, when the modified geopolymer mortar is used for fire protection of steel structural members or composite components whose exterior is a steel structure, the construction steps include:

[0016] First, the surface of the steel structural components is derusted;

[0017] Then, a roughening liquid is applied to the surface of the rust-removed steel structural components to form a roughening material layer;

[0018] Finally, apply the modified geopolymer mortar to form a protective layer.

[0019] Furthermore, when the modified geopolymer mortar is used to provide fire protection for concrete components, the construction steps include:

[0020] First, the surface of the concrete component is roughened;

[0021] Then, an interface agent is applied to the surface of the concrete member;

[0022] Finally, apply the modified geopolymer mortar to form a protective layer.

[0023] Furthermore, the protective layer formed by the modified polymer mortar is applied in layers according to its thickness, and metal wire mesh can be embedded between the layers.

[0024] Furthermore, the metal wire mesh is made of galvanized iron wire mesh or stainless steel wire mesh.

[0025] Furthermore, when the modified geopolymer mortar is used to reinforce and modify the structural components, the construction steps include:

[0026] First, longitudinal reinforcement bars are installed around the perimeter of the structural member;

[0027] Then, stirrups are tied to the longitudinal reinforcement at longitudinal intervals;

[0028] Finally, apply the modified geopolymer mortar with a thickness of 20-60mm;

[0029] The stirrup consists of two semi-circular steel bars that are lapped, tied, or welded together to form the stirrup.

[0030] When the thickness of the modified geopolymer mortar layer is greater than 35mm, a metal wire mesh needs to be embedded in the inner layer of the mortar.

[0031] By adopting the above technical solution, the present invention can achieve the following technical effects:

[0032] This modified geopolymer mortar hardens quickly, has high early strength, moderate consistency, good water retention, and is easy to apply, facilitating layered application. It is suitable for fire protection of structural components, increasing their fire resistance to 2-4 hours or more. Furthermore, this modified geopolymer mortar not only possesses high strength at room temperature but also maintains high compressive strength at and after high temperatures. In the event of a fire, the fire-resistant protective layer based on it can bear part of the vertical load, effectively improving overall fire resistance and demonstrating excellent application results in structural reinforcement and renovation projects. Attached Figure Description

[0033] Figure 1 This is a temperature rise curve of the center point of the modified geopolymer mortar test block according to an embodiment of the present invention;

[0034] Figure 2 The compressive strength of the modified geopolymer mortar at high temperature according to the embodiments of the present invention. Compressive strength without exposure to high temperatures The ratio of [value] to temperature T (°C) is plotted as a function of [ratio].

[0035] Figure 3 The compressive strength of the modified geopolymer mortar after high temperature in the embodiments of the present invention is Compressive strength without exposure to high temperatures The relationship between the ratio and temperature T (°C);

[0036] Figure 4 This is a cross-sectional schematic diagram of an embodiment of the present invention in which modified geopolymer mortar is applied to the surface of a steel-concrete composite column as a fireproof protective layer for the steel-concrete composite column.

[0037] Figure 5 This is a comparison between the steel pipe temperature calculated by finite element method and the measured temperature in an embodiment of the present invention.

[0038] Figure 6 This is a curve showing the relationship between the axial deformation of a steel-concrete composite column coated with modified geopolymer mortar as a fireproof protective layer and the time of exposure to fire, according to an embodiment of the present invention.

[0039] Figure 7 This is a cross-sectional schematic diagram of an embodiment of the present invention in which modified geopolymer mortar is applied to the surface of a reinforced concrete column as a fireproof protective layer for the reinforced concrete column.

[0040] Figure 8 This is a cross-sectional schematic diagram of an embodiment of the present invention, in which modified geopolymer mortar is applied to the surface of a reinforced concrete column for reinforcement and modification.

[0041] Figure 9 This is a schematic diagram of the binding of the reinforcing stirrups in an embodiment of the present invention;

[0042] Icons: 1. Concrete; 2. Steel pipe; 3. Modified polymer mortar layer; 4. Textured material layer; 5. Metal wire mesh; 6. Longitudinal reinforcement of reinforced concrete column; 7. Stirrups of reinforced concrete column; 8. Interface agent; 9. Longitudinal reinforcement of reinforcement layer; 10. Stirrups of reinforcement layer. Detailed Implementation

[0043] Example

[0044] Combination Figures 1 to 9 As shown, this embodiment provides a modified geopolymer mortar that can be applied to the outer surface of structural components. The modified geopolymer mortar comprises the following raw materials by weight: 31-35 parts sodium hydroxide, 200-210 parts water glass solution, 1450-1550 parts blast furnace slag, 1450-1550 parts fly ash, 90-450 parts silica fume, 4450-4550 parts natural river sand, 5-8 parts polypropylene fiber, 90-400 parts hollow glass microspheres, and 1110-1320 parts water.

[0045] The equivalent thermal conductivity of the modified geopolymer mortar is... [W / (m·K)] and its thickness (m) satisfies the following relationship:

[0046]

[0047] The applicable range for the thickness di of the modified geopolymer mortar is 0.0015m-0.060m.

[0048] The preparation method of the modified geopolymer mortar includes the following steps: First, sodium hydroxide is added to water glass solution and stirred to prepare an alkaline activator, which is then cooled to room temperature for later use; then, blast furnace slag and fly ash are weighed at a mass ratio of 1:1 and mixed evenly with silica fume of the corresponding proportion; then, the prepared alkaline activator is slowly added to the above-mentioned mixed dry materials, and the required amount of water is added at the same time, and the mixture is stirred thoroughly until a uniform slurry is obtained; finally, a mixture of polypropylene fiber, river sand and hollow glass microspheres that has been mixed evenly is added to the slurry, and the mixture is stirred continuously until all components are evenly distributed, thus obtaining the modified geopolymer mortar.

[0049] The modified geopolymer mortar described above utilizes silica-alumina solid waste to replace cement in mortar preparation, significantly improving the utilization rate of solid waste resources and substantially reducing energy consumption and carbon dioxide emissions during cement production. It possesses strong fire-resistant and heat-insulating properties, and the introduction of silica fume into the raw materials gives it high strength. The inclusion of hollow glass microspheres with low thermal conductivity further enhances the heat insulation performance of the geopolymer mortar, increasing the fire resistance limit of structural components to over 2-4 hours. Furthermore, this modified geopolymer mortar not only exhibits high strength at room temperature but also maintains high compressive strength at and after high temperatures. In the event of a fire, the fireproof protective layer based on it can bear part of the vertical load, effectively improving overall fire resistance and demonstrating excellent application results in structural reinforcement and renovation projects. Simultaneously, this modified geopolymer mortar can cure rapidly, has high early strength, moderate consistency, good water retention, and is easy to apply.

[0050] Specifically, in this embodiment, the modified geopolymer mortar comprises the following components by weight: 33.6 parts sodium hydroxide, 206.4 parts water glass solution, 1500 parts blast furnace slag, 1500 parts fly ash, 300 parts silica fume, 4500 parts natural river sand, 6.3 parts polypropylene fiber, 360 parts hollow glass microspheres, and 1110 parts water.

[0051] The water glass solution has a Baumé degree of 50, a modulus of 2.25, a SiO2 content of 29.99%, and a Na2O content of 13.75%. The sodium hydroxide content is 96% by mass. Preferably, 16.24 parts of sodium hydroxide are added per 100 parts of water glass solution; after adding sodium hydroxide according to the above ratio, the modulus of the water glass solution is 1.

[0052] The main chemical components of the blast furnace slag, expressed as a percentage by mass, are: calcium oxide 34%, silicon dioxide 34.5%, aluminum oxide 17.7%, sulfur trioxide 1.64%, iron oxide 1.03%, and magnesium oxide 6.01%.

[0053] The main chemical components of the fly ash, expressed as a percentage by mass, are: calcium oxide 4.01%, silicon dioxide 53.99%, aluminum oxide 31.15%, sulfur trioxide 0.73%, iron oxide 4.16%, magnesium oxide 1.01%, potassium oxide 2.04%, and titanium dioxide 1.13%.

[0054] The silica fume contains more than 90% silica, the natural river sand has a particle size of 0.1-0.5 mm, the polypropylene fiber has a length of 9 mm, and the hollow glass microspheres have a particle size of 10-250 μm and a wall thickness of 1-2 μm.

[0055] The modified geopolymer mortar with a consistency of 47 mm and a segregation of 11 mm was prepared using the above preparation method. It has moderate consistency and good water retention. The modified geopolymer mortar was applied to the surface of steel pipes and concrete. Practical results show that it is easy to apply and convenient to construct.

[0056] The following is a detailed verification of the fire resistance of the modified geopolymer mortar coating, using conventional geopolymer mortar as a control group:

[0057] The specific verification method is as follows: the modified geopolymer mortar prepared above is made into mortar blocks with an edge length of 70.7 mm, placed in a box-type resistance furnace for heating, the heating rate is set to 12℃ / min, heating for 80 min, and constant temperature for 31 min; and the heating curve of the center point of the mortar block is recorded.

[0058] like Figure 1 As shown, the temperature rise curves at the center point of the modified geopolymer mortar specimen and the conventional geopolymer mortar specimen are displayed. It can be seen that when the modified geopolymer mortar specimen is heated for 40 min, 80 min, and held at a constant temperature for 30 min, the temperature at the center point of the specimen is reduced by 20.5℃, 116.16℃, and 78℃ respectively compared to the geopolymer mortar specimen without hollow glass microspheres. This indicates that the modified geopolymer mortar with the optimized mix ratio has better thermal insulation performance than the geopolymer mortar without hollow glass microspheres.

[0059] The following test results demonstrate the compressive strength of the modified geopolymer mortar specimens:

[0060] The specific verification method was as follows: two types of high-temperature performance tests were conducted on modified geopolymer mortar specimens with an edge length of 70.7 mm: first, compressive strength tests were performed at five temperatures: 100℃, 300℃, 500℃, 650℃, and 800℃; second, the compressive strength was measured after the specimens were subjected to high temperatures ranging from 100℃ to 800℃ (with adjacent temperature points spaced 100℃ apart) and then allowed to cool naturally to room temperature. The electric furnace heating power was 10℃ / min, and the holding time was 6 hours.

[0061] The above experiments revealed the changes in compressive strength of modified geopolymer mortar under different temperatures and after high-temperature cooling.

[0062] like Figure 2 The figure shows the compressive strength of the modified geopolymer mortar at high temperature. Compressive strength without exposure to high temperatures The relationship between the ratio and temperature T (°C) is given, and the corresponding fitting calculation formula is provided as follows:

[0063]

[0064] like Figure 3 The figure shows the compressive strength of the modified geopolymer mortar after high temperature. Compressive strength without exposure to high temperatures The relationship between the ratio and temperature T (°C) is given, and the corresponding fitting calculation formula is provided as follows:

[0065]

[0066] As can be seen from the above, the modified geopolymer mortar not only has high strength at room temperature, but also maintains high compressive strength at high temperature and after high temperature.

[0067] The modified geopolymer mortar described above can serve as a fireproof protective layer for various structural components and can also be used for the reinforcement and modification of structural components. The following is a detailed explanation:

[0068] 1. Fireproof protective layer applied to the surface of steel-concrete composite columns;

[0069] like Figure 4 As shown in the cross-sectional diagram, the steel-concrete composite column has a height of 3810 mm, an outer diameter of 325 mm, and a wall thickness of 8 mm. The core concrete 1 is C30 commercial concrete, and the steel pipe 2 is made of 20# steel. The modified geopolymer mortar layer 3 has a thickness of 22 mm.

[0070] The thickness of the modified geopolymer mortar layer 3 is determined based on the equivalent thermal conductivity λ of the modified geopolymer mortar and the thickness of the protective layer. Using the formula for calculating (m), the equivalent thermal conductivity of the modified geopolymer mortar protective layer with a thickness of 22 mm is calculated to be 0.4385 W / (m·K). Figure 5 As shown, the results of the finite element calculation of the temperature of steel pipe 2 under this condition are compared with the measured temperature. The two curves match well with small errors, verifying the accuracy of the above formula. The above calculation formula can be used to calculate the equivalent thermal conductivity of modified polymer mortar based on the known protective layer thickness, and then predict the fire resistance limit of the component through finite element analysis, providing a quantitative basis for whether the fire protection design meets the requirements.

[0071] The construction method for the fireproof protective layer of the steel-concrete composite column is as follows:

[0072] First, use an angle grinder to remove the rust stains from the surface of steel pipe 2, and then apply anti-rust paint.

[0073] Then, the outer wall of the steel-concrete composite column is roughened with a roughening material to form a roughening material layer 4;

[0074] After the roughening material has sufficient strength, apply the first layer of modified geopolymer mortar with a thickness of 12mm;

[0075] After the modified geopolymer mortar has hardened, a layer of metal wire mesh 5 is wrapped around its surface. The metal wire mesh can be galvanized iron wire mesh or stainless steel iron wire mesh.

[0076] After the mesh is installed, apply a second layer of modified geopolymer mortar with a thickness of 10mm;

[0077] After the modified polymer mortar has fully hardened, spray it with water for one week for curing.

[0078] The fire resistance of steel-concrete composite columns coated with the modified geopolymer mortar as a fireproof protective layer was verified to be 128 min; while the fire resistance of steel-concrete composite columns coated with the same thickness of ordinary geopolymer mortar as a fireproof protective layer was 86 min; and the fire resistance of steel-concrete composite columns without fireproof protection was only 25 min.

[0079] The results show that using the modified geopolymer mortar as a fireproof protective layer can significantly improve the fire resistance limit of steel-concrete composite columns, and its fire protection effect is significantly better than that of geopolymer mortar without hollow glass microspheres. Meanwhile, as... Figure 6 The figure shows the relationship between the axial deformation of a steel-concrete composite column coated with modified genomic mortar as a fireproof protective layer and the time of exposure to fire. Expansion deformation is defined as negative and compression deformation as positive, with a load ratio of 0.5. It can be seen that the steel-concrete composite column coated with modified genomic mortar as a fireproof protective layer has good fire resistance.

[0080] 2. Fireproof protective layer applied to the surface of reinforced concrete columns;

[0081] like Figure 7 As shown in the cross-sectional diagram, the reinforced concrete column is 3600mm high and 400mm long on each side. Concrete 1 is C30 commercial concrete, the longitudinal reinforcement 6 of the reinforced concrete column is 12C16, and the stirrups 7 of the reinforced concrete column are A10@100 / 200. The thickness of the modified polymer mortar layer 3 is 25mm.

[0082] The construction method for the fireproof protective layer of the reinforced concrete column is as follows:

[0083] First, the surface of the reinforced concrete column is roughened by chiseling, and then an interface agent 8 is applied.

[0084] After the interface agent dries, apply the first layer of modified geopolymer mortar to its surface, with a thickness of 15mm;

[0085] After the modified geopolymer mortar hardens, a layer of metal wire mesh 5 is wrapped around its surface, which is made of galvanized iron wire mesh;

[0086] After the mesh is installed, apply a second layer of modified geopolymer mortar with a thickness of 10mm;

[0087] After the modified polymer mortar has fully hardened, spray it with water for one week for curing.

[0088] Verification showed that the fire resistance limit of reinforced concrete columns coated with modified geopolymer mortar as a fireproof protective layer was significantly improved.

[0089] 3. Applied to the surface of reinforced concrete columns for reinforcement and renovation;

[0090] like Figure 8 As shown in the cross-sectional diagram, the reinforced concrete column has a height of 3600mm and a side length of 400mm. Concrete 1 is C30 commercial concrete, the longitudinal reinforcement 6 of the reinforced concrete column is 12C12, and the stirrups 7 of the reinforced concrete column are A10@100. A 30mm thick modified polymer mortar is applied to reinforce the reinforced concrete column.

[0091] The reinforcement and renovation method for the reinforced concrete column is as follows:

[0092] First, reinforcing longitudinal bars 9 (8C16) are inserted around the concrete column that needs to be reinforced.

[0093] According to the reinforcement design requirements, tie the reinforcement layer stirrups 10 (A8@200); the reinforcement layer stirrups 10 are as follows: Figure 9 As shown, two "[" shaped steel bars are used to form a rectangular hoop by lapping or welding. The lap length is not less than 200mm. The lap positions should be staggered to avoid the diagonal crack intersecting with the lap joints of the two side stirrups.

[0094] Finally, modified geopolymer mortar is applied to the column surface to form modified geopolymer mortar layer 3, which has a thickness of 30mm.

[0095] After the modified polymer mortar has fully hardened, spray it with water for one week for curing.

[0096] The modified geopolymer mortar, used as a reinforcement layer, only requires a thin layer of mortar to be applied to the reinforced concrete column, eliminating the need for re-formwork and pouring, making construction convenient and quick. Furthermore, reinforced concrete columns reinforced with longitudinal bars and stirrups embedded in the modified geopolymer mortar layer exhibit significantly improved bending and shear capacity after reinforcement.

[0097] It should be understood that the above are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention.

[0098] The accompanying drawings used in the above description of the embodiments only illustrate certain embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

Claims

1. A modified geopolymer mortar, which can be applied to the outer surface of a structural member, characterized in that, wherein the modified geopolymer mortar comprises the following raw materials in parts by weight: sodium hydroxide 31-35 parts, water glass solution 200-210 parts, blast furnace slag 1450-1550 parts, fly ash 1450-1550 parts, silica fume 90-450 parts, natural river sand 4450-4550 parts, polypropylene fiber 5-8 parts, hollow glass microbeads 90-400 parts, and water 1110-1320 parts; The equivalent thermal conductivity of the modified polymer mortar with its thickness The following relation should be satisfied: Wherein, the thickness di of the modified polymer mortar is 0.0015m-0.060m; the equivalent thermal conductivity is W / (m·K); the thickness is m.

2. The modified geoploymer mortar according to claim 1, characterized in that, the water glass solution has a Baume degree of 50 and a modulus of 2.

25.

3. The modified geoploymer mortar according to claim 1, characterized in that, The natural river sand has a particle size of 0.1-0.5 mm, the polypropylene fiber has a length of 6-19 mm, and the hollow glass microbeads have a particle size of 10-250 μm and a wall thickness of 1-2 μm.

4. The modified geoploymer mortar according to claim 1, characterized in that, After the modified geopolymer mortar is applied to the outer surface of the structural member to form a protective layer, water spraying maintenance is required, and the temperature difference between the maintenance water and the surface of the protective layer is not greater than 15℃.

5. Use of the modified geopolymer mortar according to any one of claims 1 to 4 on structural elements, characterized in that, Fireproof protection and / or reinforcement reconstruction for the structural member.

6. Use of the modified geopolymer mortar according to claim 5 on structural elements, characterized in that, When the modified geopolymer mortar is used for fireproof protection of a steel structural member or a combined member with a steel structural member on the outside, the construction steps include: First, rust removal is performed on the surface of the steel structural member; Then, a roughening liquid is applied to the surface of the rust-removed steel structural member to form a roughening material layer; Finally, the modified geopolymer mortar is applied to form a protective layer.

7. Use of the modified geopolymer mortar according to claim 5, characterized in that, When the modified geopolymer mortar is used for fireproof protection of a concrete structural member, the construction steps include: First, the surface of the concrete structural member is chiseled; Then, an interface agent is applied to the surface of the concrete structural member; Finally, the modified geopolymer mortar is applied to form a protective layer.

8. Use of the modified geopolymer mortar according to claim 5 on structural elements, characterized in that, The protective layer formed by the modified geopolymer mortar is applied in layers according to its thickness, and metal wire mesh can be embedded between the layers.

9. Use of the modified geopolymer mortar according to claim 8 on structural elements, characterized in that, The metal wire mesh is made of galvanized iron wire mesh or stainless steel wire mesh.

10. Use of the modified geopolymer mortar according to claim 5 on structural elements, characterized in that, When the modified geopolymer mortar is used for reinforcement reconstruction of the structural member, the construction steps include: First, longitudinal reinforcement is embedded in the periphery of the structural member; Then, stirrups are bound along the longitudinal direction at intervals on the longitudinal reinforcement; Finally, the modified geopolymer mortar with a thickness of 20-60 mm is applied; The stirrup is formed by overlapping and binding or welding two half-ring steels. When the thickness of the applied modified geopolymer mortar layer is greater than 35 mm, metal wire mesh needs to be embedded in the inner layer of the mortar.

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