High-sulfate-erosion-resistant organic-inorganic composite board and preparation method and application thereof

Abstract

The application relates to the technical field of building materials, in particular to an organic modified cement-based plate material with high sulfate erosion resistance and a preparation method and application thereof, and aims to solve the problem that the durability of concrete materials in a sulfate erosion environment is easily damaged. The application discloses an organic modified cement-based plate material with high sulfate erosion resistance and a preparation method and application thereof. The organic modified cement-based plate material is prepared by adopting a vibration compression vacuum three-dimensional coupling forming technology, the porosity is reduced, the chemical reaction of organic-inorganic materials is enhanced, the waterproofness and the performance of erosion medium of the cement-based material are improved, and therefore the sulfate erosion resistance of the cement-based plate material is improved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to an organic-inorganic composite board with high resistance to sulfate attack, its preparation method and application. Background Technology

[0002] Cement-based building structures are prone to damage and failure due to the complexity of their service environment and external environmental influences. The destructive process of sulfate in cement-based building structures is a complex physicochemical change. Sulfate ions, during water infiltration, react with hydration products or unhydrated particles in the cement-based material within pores and interfacial transition zones, generating expansive reaction products. This leads to stress concentration within the pores. When the stress exceeds the intrinsic stress of the inorganic material, cracks form. The presence of these cracks further exacerbates the transport of sulfate ions with water, resulting in even greater damage.

[0003] Current methods for resisting sulfate attack on cement-based building structures primarily rely on external organic coatings. However, the widespread use of these organic coatings is significantly limited due to their inherent low strength and susceptibility to aging. Therefore, improving the density and water-blocking capacity of building structural materials is a crucial direction for enhancing their resistance to sulfate attack. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the purpose of this invention is to provide a method for preparing an organic-inorganic composite board with high resistance to sulfate attack. The prepared organic-inorganic composite board with high resistance to sulfate attack has the advantages of high density and high toughness. The organic components in the composite board have strong water-blocking ability and high protection against sulfate ion attack.

[0005] Another object of the present invention is to provide an organic-inorganic composite board with high resistance to sulfate attack obtained by the above preparation method.

[0006] Another object of the present invention is to provide the application of organic-inorganic composite panels in the resistance to sulfate attack.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for preparing an organic-inorganic composite board with high resistance to sulfate attack includes the following steps:

[0009] (1) Mix cement and dense graded sand evenly, mix water-based organic emulsion and water evenly, and stir together to obtain a mixed slurry;

[0010] (2) Pour the mixed slurry obtained in step (1) into a mold, vibrate, and let stand to obtain organic modified cement-based plastic slurry;

[0011] (3) The organic modified cement-based plastic slurry in step (2) is vacuumed and vibrated to form a board;

[0012] (4) After demolding the board obtained in step (3), the board is cured to obtain the organic-inorganic composite board with high resistance to sulfate attack.

[0013] Preferably, the mass ratio of sand to cement in step (1) is 0-2, and the water-cement ratio is 0.15-0.45.

[0014] Preferably, the organic emulsion in step (1) has a mass of 0.5%-20% of the cement.

[0015] Preferably, the vibration time in step (2) is 60±10s; the settling time is 15-120min, until a plastic slurry with a liquid plasticity index of 0 to 0.25 is formed.

[0016] Preferably, the vacuuming time in step (3) is 0.5 min to 5 min.

[0017] Preferably, the pressing and molding step in step (3) is to compact the slurry and vibrate it under a pressure of 0.1-1 MPa.

[0018] Preferably, the vibration frequency is 15Hz-50Hz and the vibration time is 1-10±5min.

[0019] Preferably, the curing step involves curing the material for 7 days at 20±2℃ and 50±10% relative humidity after demolding, and then immersing it in water for curing until the specified age.

[0020] An organic-inorganic composite board with high resistance to sulfate attack, prepared by the above method.

[0021] The above-mentioned organic-inorganic composite panels are used in the resistance to sulfate attack.

[0022] Compared with the prior art, the present invention has the following advantages and effects:

[0023] (1) This invention uses vibration pressing and vacuum three-dimensional coupling molding technology combined with emulsion to prepare organic-inorganic composite boards. The vibration pressing and vacuum three-dimensional coupling molding process can reduce the bubbles generated by the emulsion in the cement-based material, enhance the organic-inorganic crosslinking reaction of cement and emulsion, improve the durability and density of the board, and further enhance the interaction between organic and inorganic materials.

[0024] (2) The organic-inorganic composite board prepared by the present invention has high density and toughness.

[0025] (3) The organic components in the organic-inorganic composite board prepared by the present invention have a strong water-blocking effect and a strong effect against sulfate corrosion. Attached Figure Description

[0026] Figure 1 A schematic diagram illustrating the principle of preparing organic modified cement-based boards using a vibration pressing and vacuum three-dimensional coupling molding technique.

[0027] Figure 2(a) shows the sulfate ion erosion depth of the comparative and example examples after 30 cycles of wet and dry sulfate erosion.

[0028] Figure 2(b) shows the sulfate ion erosion depth of the comparative and example examples after 60 cycles of wet and dry sulfate erosion.

[0029] Figure 2(c) shows the sulfate ion erosion depth of the comparative and example examples after 90 cycles of sulfate dry-wet erosion.

[0030] Figure 3(a) shows the degree of damage caused by sulfate to the comparative and example samples after 30 cycles of wet and dry sulfate erosion.

[0031] Figure 3(b) shows the degree of damage caused by sulfate to the comparative and example samples after 90 cycles of wet and dry sulfate erosion.

[0032] Figure 3(c) shows the degree of damage caused by sulfate to the comparative and example samples after 180 cycles of wet and dry sulfate erosion.

[0033] Figure 4 shows the XPS plots of Ca in Comparative Example 1(a) and Example 1(b).

[0034] Specific implementation methods

[0035] To make the technical solution and advantages of the present invention clearer, the present invention will be further described below in conjunction with comparative examples and embodiments.

[0036] Comparative Example 1

[0037] The specific steps of a method for preparing an organic-inorganic composite board are as follows:

[0038] (1) Mix 6000g of cement, 333g of acrylic emulsion and 1345g of water evenly and stir together to obtain organic modified cement-based plastic paste.

[0039] (2) Place the slurry obtained in step (1) into a fixed iron mold, and vibrate it on a vibrating table for 60 seconds.

[0040] (3) The board obtained in step (2) is cured at 20 (±2)℃ and 50 (±10)% relative humidity for 7 days, and then cured in water for 21 days.

[0041] Comparative Example 2

[0042] The specific steps of a method for preparing an organic-inorganic composite board with high resistance to sulfate attack are as follows:

[0043] (1) Mix 6000g of cement and 1345g of water evenly and stir together to obtain organic modified cement-based plastic paste;

[0044] (2) Pour the slurry obtained in step (1) into a fixed iron mold, place it on a vibrating table and vibrate for 60 seconds until the slurry reaches a hard shrinkage state, and then place it into a vibrating pressing vacuum forming equipment.

[0045] (3) Evacuate the molding equipment in step (2) for 3 minutes, press the slurry with the pressure head under a pressure of 0.8 MPa, and vibrate at a vibration frequency of 18 Hz for 10 minutes.

[0046] (4) The board obtained in step (3) is cured at 20 (±2)℃ and 50 (±10)% relative humidity for 7 days, and then cured in water for 21 days.

[0047] Example 1

[0048] The specific steps of a method for preparing an organic-inorganic composite board with high resistance to sulfate attack are as follows:

[0049] (1) Mix 6000g of cement, 333g of acrylic emulsion and 1345g of water evenly and stir together to obtain organic modified cement-based plastic paste.

[0050] (2) Pour the slurry obtained in step (1) into a fixed iron mold, place it on a vibrating table and vibrate for 60 seconds until the slurry reaches a hard shrinkage state, and then place it into a vibrating pressing vacuum forming equipment.

[0051] (3) Evacuate the molding equipment in step (2) for 3 minutes, press the slurry with the pressure head under a pressure of 0.8 MPa, and vibrate at a vibration frequency of 18 Hz for 10 minutes.

[0052] (4) The board obtained in step (3) is cured at 20 (±2)℃ and 50 (±10)% relative humidity for 7 days, and then cured in water for 21 days.

[0053] Example 2

[0054] The preparation process of this embodiment is basically the same as that of Example 1, except that the acrylate emulsion is changed to styrene-butadiene emulsion in step (1).

[0055] The sulfate ion erosion depth of the comparative and exemplary cases after 30, 60, and 90 cycles of wet-dry sulfate erosion is shown in Figures 2(a)-(c). The degree of sulfate damage to the comparative and exemplary cases after 30, 90, and 180 cycles of wet-dry sulfate ion erosion is shown in Figures 3(a)-(c). The vibration pressing vacuum three-dimensional coupling molding technology can significantly improve the sulfate erosion resistance of composite boards. With the addition of organic emulsion, the sulfate erosion resistance is also significantly improved.

[0056] Figure 4 shows the XPS plots of Ca elemental composition for Comparative Example 1 and Example 1. Under different molding methods, the chemical interaction between the organic emulsion and the inorganic product can be represented by the Ca(COOH)₂ content. Compared to conventional molding techniques, the Ca(COOH)₂ content produced by the vibration pressing vacuum three-dimensional coupling molding method can reach more than four times that of conventional molding techniques. The enhanced organic-inorganic interaction forces result in a denser matrix with stronger resistance to sulfate attack.

[0057] Vibration pressing and vacuum three-dimensional coupling molding technology can significantly enhance the density of composite panels. Simultaneously, the addition of organic emulsions allows latex particles to fill the pores of the inorganic cementitious system, further increasing the density of the composite material. Secondly, this technology reduces the distance between latex particles and inorganic particles, thereby enhancing the organic-inorganic interaction and improving the overall integrity of the composite panel.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any equivalent changes, modifications, or variations made by those skilled in the art to the above embodiments using the technical solutions of the present invention shall fall within the scope of the technical solutions of the present invention.

Claims

1. A method for preparing an organic-inorganic composite board with high resistance to sulfate attack, characterized in that, Includes the following steps: (1) Mix cement and dense graded sand evenly, mix water-based organic emulsion and water evenly, and stir together to obtain a mixed slurry; (2) Pour the mixed slurry obtained in step (1) into a mold, vibrate, and let stand to obtain organic modified cement-based plastic slurry; (3) The organic modified cement-based plastic slurry in step (2) is vacuumed and vibrated to form a board; (4) After demolding the board obtained in step (3), cure it to obtain the organic-inorganic composite board with high resistance to sulfate attack; The water-based organic emulsion in step (1) has a mass of 0.5%-20% of the cement, and the water-based organic emulsion is an acrylic emulsion or a styrene-butadiene emulsion. The vibration time in step (2) is 60±10s, and the settling time is 15-120min, until a plastic slurry with a liquid plasticity index of 0~0.25 is formed; The vacuuming time in step (3) is 0.5min-5min. The pressing and molding step is to compact the slurry and vibrate it under a pressure of 0.1-1Mpa. The vibration frequency is 15Hz-50Hz and the vibration time is 10±5min. The curing step is to cure it for 7 days in an environment of 20±2℃ and 50±10% relative humidity after demolding, and then put it in water to cure it to the specified age.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of sand to cement is 0-2, and the water-cement ratio is 0.15-0.

45.

3. The organic-inorganic composite board with high resistance to sulfate attack prepared by the preparation method according to any one of claims 1 to 2.

4. The application of the organic-inorganic composite board with high sulfate resistance as described in claim 3 in sulfate resistance.

Images