A method for preparing epoxy resin modified coal gangue concrete

Abstract

This invention relates to the field of coal gangue concrete technology, specifically to a method for preparing epoxy resin modified coal gangue concrete. To address the problems of high cost and complex processes in existing methods for improving the mechanical properties of coal gangue concrete, a new method for preparing epoxy resin modified coal gangue concrete is provided, comprising the following steps: 1) mixing epoxy resin and a curing agent to form an epoxy resin solvent; 2) coating the surface of coal gangue aggregate with a layer of epoxy resin solvent; 3) uniformly adhering fine sand to the surface of the coal gangue aggregate, and drying to obtain modified coal gangue aggregate; 4) uniformly mixing the modified coal gangue aggregate, cement, slag, fly ash, sand, and water, and then adding a water-reducing agent and mixing thoroughly to obtain epoxy resin modified coal gangue concrete. The preparation method of this invention has the advantages of low cost, good economy, rapid and convenient modification process, low environmental requirements, and strong operability.

Description

Technical Field

[0001] This invention relates to the field of coal gangue concrete technology, specifically to a method for preparing epoxy resin modified coal gangue concrete. Background Technology

[0002] With the rapid development of my country's economy and the continuous expansion of infrastructure construction, the consumption of concrete, as an important component of building materials, is also increasing year by year. However, the aggregates in traditional concrete raw materials mainly come from natural stone, such as river sand and gravel. Long-term large-scale mining has caused serious damage to the natural environment. Therefore, finding alternative aggregates to sand and gravel and achieving sustainable resource development has become a key concern in the current building materials industry.

[0003] Coal gangue is a byproduct of coal mining and washing. my country produces a large amount of coal gangue annually, with its annual accumulation rapidly increasing and occupying significant land resources. Furthermore, long-term stockpiled coal gangue is prone to spontaneous combustion, producing toxic gases and causing serious environmental pollution. In recent years, the resource utilization of coal gangue has received widespread attention. Since the main mineral components of coal gangue are similar to those of natural aggregates, simply crushing and screening raw coal gangue for use as concrete aggregate can not only achieve effective resource utilization of coal gangue and reduce environmental pollution, but also reduce the mining of natural stone and alleviate the demand for natural sand and gravel aggregates. However, compared to natural sand and gravel aggregates, coal gangue has a higher water absorption rate, is more porous, and has a higher crushing index, resulting in relatively lower strength and durability of this type of concrete, limiting its widespread application in engineering fields.

[0004] To improve the mechanical properties of coal gangue concrete, admixtures, fibers, and mineral admixtures can be added. However, existing methods for improving the performance of coal gangue concrete often have drawbacks such as high cost and complex processes, which hinder the promotion and application of coal gangue concrete in engineering projects. Summary of the Invention

[0005] In order to solve the problems of high cost and complex process in existing methods for improving the mechanical properties of coal gangue concrete, this invention provides a new method for preparing epoxy resin modified coal gangue concrete.

[0006] This invention is achieved using the following technical solution:

[0007] A method for preparing epoxy resin modified coal gangue concrete includes the following steps: 1) mixing epoxy resin and curing agent to form an epoxy resin solvent; 2) immersing coal gangue aggregate in the epoxy resin solvent to coat the surface of the coal gangue aggregate with a layer of epoxy resin solvent; 3) uniformly adhering fine sand to the surface of the coal gangue aggregate coated with a layer of epoxy resin solvent, and then drying it to obtain modified coal gangue aggregate; 4) uniformly mixing the modified coal gangue aggregate, cement, slag, fly ash, sand, and water, then adding a water-reducing agent and continuing to stir until uniformly mixed to obtain epoxy resin modified coal gangue concrete.

[0008] Principle Explanation: ① Epoxy Resin Modification: Epoxy resin reacts with the curing agent to form a three-dimensional network structure. This structure can effectively encapsulate coal gangue aggregate, fill the natural defects in the coal gangue aggregate, and effectively improve the physical defects such as high water absorption, low crushing value, and high porosity of coal gangue aggregate, thereby improving the overall strength and stability of coal gangue aggregate; ② Fine Sand Filling: The fine sand particles are uniformly attached to the surface of the coal gangue aggregate after being coated with epoxy resin. This not only increases the surface roughness of the coal gangue aggregate and enhances the interfacial bonding performance between the coal gangue aggregate and cement paste, but also fully exerts the filling effect, thereby improving the density of coal gangue concrete.

[0009] Furthermore, in step 1), the mass ratio of epoxy resin to curing agent is 1:1.

[0010] Further, in step 4), the mass ratio of modified coal gangue aggregate, cement, slag, fly ash, sand, water, and water-reducing agent is 3-5:1:0.20-0.26:0.09-0.11:1.67-2.67:0.60-0.64:0.003-0.004.

[0011] Furthermore, in step 4), the mass ratio of modified coal gangue aggregate, cement, slag, fly ash, sand, water, and water-reducing agent is 4.267:1:0.23:0.1:2.03:0.63:0.0037.

[0012] Further, in step 3), the particle size of the fine sand is 0.15-0.5 mm and the fineness modulus is 0.8-1.0; in step 2), the particle size of the coal gangue aggregate is 5-25 mm; and in step 4), the particle size of the sand is 0.1-0.3 mm.

[0013] Furthermore, in step 2), the mass ratio of coal gangue aggregate particles according to particle size distribution is 5~10mm:10~16mm:16~25mm = 4.5~5.5:3.5~4.5:0.5~1.5.

[0014] Further, in step 2), the coal gangue aggregate is immersed in epoxy resin solvent and then stirred evenly.

[0015] Furthermore, in step 3), the drying process involves natural drying for 24 hours or rapid drying by oven for 6 hours.

[0016] Furthermore, the coal gangue aggregate in step 2) is either self-igniting coal gangue or non-self-igniting coal gangue.

[0017] Furthermore, the epoxy resin is a two-component epoxy resin, which has high bonding strength and durability.

[0018] A method for preparing epoxy resin modified coal gangue includes the following steps: 1) mixing epoxy resin and curing agent to form an epoxy resin solvent; 2) immersing coal gangue aggregate in the epoxy resin solvent so that the surface of the coal gangue aggregate is coated with a layer of epoxy resin solvent; 3) uniformly attaching fine sand to the surface of the coal gangue aggregate coated with a layer of epoxy resin solvent, and then drying it to obtain modified coal gangue aggregate.

[0019] When used, the modified coal gangue aggregate prepared by this method is used as an aggregate in concrete raw materials.

[0020] The beneficial effects of this invention are as follows:

[0021] 1) Compared with the prior art, the present invention has the advantages of low cost and good economy, fast and convenient modification process, low environmental requirements and strong operability.

[0022] 2) The mechanical strength of the modified coal gangue concrete is significantly improved, and the aggregate performance is more stable, which can effectively meet the needs of construction projects with strength requirements.

[0023] 3) The density and interfacial properties of coal gangue concrete are effectively improved, which enhances the impermeability and frost resistance of this type of concrete. The improved impermeability and density of concrete can improve its corrosion resistance, thereby effectively extending the service life of building components.

[0024] 4) Using coal gangue, an industrial waste, to prepare concrete not only reduces environmental pollution and realizes the rational use of solid waste resources, but also alleviates the existing market demand for natural sand and gravel, which is in line with the concept of sustainable development.

[0025] 5) It can realize batch modification process, pre-treatment modification process of coal gangue aggregate, the prepared coal gangue concrete has good workability, is easy to construct and has broad engineering application prospects. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The image shows the microstructure of the epoxy resin-modified coal gangue in Example 1 (the microstructures of the epoxy resin-modified coal gangue prepared in Examples 1-5 are basically the same).

[0029] Figure 2 The image shows the microstructure of the unmodified coal gangue in the comparative example.

[0030] Figure 3 The image shows the morphology of the epoxy resin modified coal gangue in Example 1 (the morphology of the epoxy resin modified coal gangue prepared in Examples 1-5 is basically the same).

[0031] Figure 4 Figure 1 shows a test block of epoxy resin modified coal gangue concrete for implementation 1.

[0032] Figure 5 The image shows a comparative example of an unmodified coal gangue concrete test block.

[0033] Figure 6 The stress-strain curves of coal gangue concrete in Examples 1-5 and the comparative examples are shown. Detailed Implementation

[0034] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0035] In this description, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0036] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0037] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0038] A method for preparing epoxy resin modified coal gangue concrete includes the following steps: 1) mixing epoxy resin and curing agent to form an epoxy resin solvent, wherein the mass ratio of epoxy resin and curing agent is 1:1, and the epoxy resin is a two-component epoxy resin; 2) immersing coal gangue aggregate in the epoxy resin solvent and stirring evenly to coat the surface of the coal gangue aggregate with a layer of epoxy resin solvent, wherein the particle size of the coal gangue aggregate is 5-25 mm. and It is either self-igniting coal gangue or non-self-igniting coal gangue; 3) Fine sand is evenly adhered to the surface of the coal gangue aggregate coated with a layer of epoxy resin solvent, and then it is naturally dried for 24 hours or rapidly dried by oven for 6 hours to obtain modified coal gangue aggregate, such as Figure 3 As shown, the fine sand has a particle size of 0.15-0.5 mm and a fineness modulus of 0.8-1.0; 4) Mix the modified coal gangue aggregate, cement, slag, fly ash, sand, and water evenly, and then add a water-reducing agent, which is a water-reducing agent, an early-strength agent, or an antifreeze agent. Continue stirring until the mixture is evenly mixed to obtain epoxy resin modified coal gangue concrete. The mass ratio of modified coal gangue aggregate, cement, slag, fly ash, sand, water, and water-reducing agent is 3-5:1:0.20-0.26:0.09-0.11:1.67-2.67:0.60-0.64:0.003-0.004.

[0039] Principle Explanation: ① Epoxy Resin Modification: Epoxy resin reacts with a curing agent to form a three-dimensional network structure, such as... Figure 1 As shown, this structure can effectively encapsulate coal gangue particles, fill the natural defects in the coal gangue aggregate, effectively improve physical defects such as high water absorption, low crushing value, and high porosity, and improve the overall strength and stability of the coal gangue aggregate; ② Fine sand filling: The fine sand particles are uniformly attached to the surface of the coal gangue aggregate after being coated with epoxy resin. This not only increases the surface roughness of the coal gangue aggregate and enhances the interfacial bonding performance between the coal gangue aggregate and the cement paste, but also fully exerts the filling effect, thereby improving the compactness of the coal gangue concrete.

[0040] To verify the performance of epoxy resin modified coal gangue concrete, the concrete prepared by the above preparation method and the material ratio shown in Table 1 was poured or pressed into shape, and then cured at room temperature. Its performance was tested and compared with that of unmodified coal gangue concrete. The test results are shown in Table 2.

[0041] Table 1 Concrete mix proportions for Examples 1-5 and Comparative Examples (unit: kg / 10L)

[0042]

[0043] Table 2. Test results of mechanical and durability properties of concrete mix proportions in Examples 1-5 and the comparative examples.

[0044]

[0045] The test results above show that the concrete prepared by the above method not only improves the 7-day (7-day curing) and 28-day (28-day curing) strength of the material by up to 30%, but also effectively improves the workability, impermeability and frost resistance of the concrete. At the same time, the comparison between Example 2 and other examples also shows that the concrete prepared by modified coal gangue without fine sand coating has significantly lower strength and significantly worse impermeability and frost resistance than that with fine sand coating. This indicates that coating with fine sand has a significant effect on improving strength.

[0046] Example 1 showed a significant improvement in strength, impermeability, and frost resistance, as well as a significant improvement in the workability of the concrete mixture. Example 2, where coal gangue was coated with epoxy resin but not with fine sand, did not show a significant increase in strength compared to the comparative example. Example 3, which reduced the sand ratio (sand / total weight of aggregates), did not show a significant improvement in workability, nor did it show a significant improvement in strength, impermeability, or frost resistance. Example 4, which increased the sand ratio, significantly improved the workability of the concrete mixture and also improved the later-stage strength, but the utilization rate of coal gangue was too low. Example 5, which did not use coal gangue or fly ash and only used cement as a binder, showed a significant increase in early strength, but the final strength improvement was not significant, and impermeability and frost resistance were not improved.

[0047] In addition, from Figure 6 It can be seen that: Example 1 has the highest stress and good strain, indicating that the concrete has high strength and good deformation capacity; Example 2 has no significant increase in stress and a slight increase in strain, indicating that the concrete strength has not increased significantly and the deformation capacity has not increased significantly; Example 3 has no significant increase in stress and a slight decrease in strain, indicating that the concrete strength has not increased significantly and the deformation capacity has decreased; Example 4 has a slight increase in stress and a decrease in strain, indicating that although the concrete strength has increased, the deformation capacity has decreased significantly; Example 5 has no significant increase in stress but a significant increase in strain, indicating that the concrete strength has not increased significantly but the deformation capacity has improved significantly.

[0048] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and they should all be covered within the protection scope of the claims.

Claims

1. A method for preparing epoxy resin modified coal gangue concrete, characterized in that, The process includes the following steps: 1) Mixing epoxy resin and curing agent to form an epoxy resin solvent; 2) Immersing coal gangue aggregate in the epoxy resin solvent to coat the surface of the coal gangue aggregate with a layer of epoxy resin solvent; 3) Evenly adhering fine sand to the surface of the coal gangue aggregate coated with a layer of epoxy resin solvent, and then drying it to obtain modified coal gangue aggregate; 4) Mixing modified coal gangue aggregate, cement, slag, fly ash, sand, and water evenly, then adding water-reducing agent, and continuing to stir until evenly mixed to obtain epoxy resin modified coal gangue concrete.

2. The method for preparing epoxy resin modified coal gangue concrete according to claim 1, characterized in that, In step 1), the mass ratio of epoxy resin to curing agent is 1:

1.

3. The method for preparing epoxy resin modified coal gangue concrete according to claim 2, characterized in that, The mass ratio of modified coal gangue aggregate, cement, slag, fly ash, sand, water, and water-reducing agent in step 4) is 3-5:1:0.20-0.26:0.09-0.11:1.67-2.67:0.60-0.64:0.003-0.

004.

4. The method for preparing epoxy resin modified coal gangue concrete according to claim 3, characterized in that, The mass ratio of modified coal gangue aggregate, cement, slag, fly ash, sand, water, and water-reducing agent in step 4) is 4.267:1:0.23:0.1:2.03:0.63:0.0037.

5. The method for preparing epoxy resin modified coal gangue concrete according to claim 4, characterized in that, In step 3), the particle size of the fine sand is 0.15-0.5 mm and the fineness modulus is 0.8-1.

0. In step 2), the particle size of the coal gangue aggregate is 5-25 mm. In step 4), the particle size of the sand is 0.1-0.3 mm.

6. The method for preparing epoxy resin modified coal gangue concrete according to claim 5, characterized in that, In step 2), the mass ratio of coal gangue aggregate particles according to particle size distribution is 5~10mm:10~16mm:16~25mm=5:4:

1.

7. The method for preparing epoxy resin modified coal gangue concrete according to claim 6, characterized in that, In step 2), the coal gangue aggregate is immersed in epoxy resin solvent and then stirred evenly.

8. The method for preparing epoxy resin modified coal gangue concrete according to claim 7, characterized in that, In step 3), the drying process involves natural drying for 24 hours or rapid drying with an oven for 6 hours.

9. The method for preparing epoxy resin modified coal gangue concrete according to claim 8, characterized in that, Epoxy resin is a two-component epoxy resin, which has high bonding strength and durability.

10. A method for preparing epoxy resin modified coal gangue, characterized in that, The process includes the following steps: 1) Mixing and stirring epoxy resin and curing agent to form epoxy resin solvent; 2) Immersing coal gangue aggregate in epoxy resin solvent so that the surface of coal gangue aggregate is coated with a layer of epoxy resin solvent; 3) Evenly adhering fine sand to the surface of coal gangue aggregate coated with a layer of epoxy resin solvent, and then drying it to obtain modified coal gangue aggregate.

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