Coal gangue roadbed material and preparation method thereof

Abstract

The application relates to the technical field of roadbed materials, and discloses a coal gangue roadbed material and a preparation method thereof. The coal gangue roadbed material comprises the following components in parts by weight: modified coal gangue 60 parts, silicate cement 15-20 parts, medium sand 20-30 parts, petalite 8-10 parts, water reducing agent 2-4 parts and water 20-30 parts; the raw material of the modified coal gangue comprises coal gangue and a water-soluble yttrium salt; the weight ratio of the coal gangue to the water-soluble yttrium salt is 10:1-2; and the preparation method of the modified coal gangue comprises the following steps: A1, adding the water-soluble yttrium salt into water, mixing uniformly to obtain a solution; A2, adding the coal gangue into the solution, mixing uniformly, adjusting the pH of the solution to 8-9, uniformly dispersing, concentrating, calcining, crushing and obtaining the modified coal gangue. Through the technical scheme, the problem of poor frost resistance and durability of the coal gangue roadbed material in the related art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of roadbed materials, in particular to a coal gangue roadbed material and a preparation method thereof. BACKGROUND

[0002] In the field of transportation infrastructure construction such as highways and railways, the roadbed, as a key component for bearing the load of the upper structure and transmitting stress, directly determines the service life, traffic safety and maintenance cost of the transportation line. With the continuous progress of transportation engineering technology in China, the performance requirements for roadbed materials are becoming increasingly stringent. Coal gangue is the main solid waste generated during coal mining and washing, and its large-scale accumulation not only occupies land resources, but also may cause environmental pollution and geological disasters. Using coal gangue for roadbed filling can not only eliminate industrial solid waste, but also reduce road construction costs, with significant economic and environmental benefits.

[0003] However, due to its porous structure and high water absorption rate, coal gangue directly used as roadbed material is prone to water absorption and softening, and has poor durability under freeze-thaw cycle conditions. With the increase of freeze-thaw cycle tests, the internal coal gangue will expand due to the volume expansion of pore water, causing frost heaving stress, which will produce new cracks and voids in the coal gangue roadbed material, seriously affecting the stability and service life of the roadbed.

[0004] Therefore, it is of great significance to develop a coal gangue roadbed material with good frost resistance and durability for prolonging the service life of the coal gangue roadbed material and improving the quality of road engineering. SUMMARY

[0005] The present application provides a coal gangue roadbed material and a preparation method thereof, which solves the problem of poor frost resistance and durability of coal gangue roadbed materials in related technologies.

[0006] The technical scheme of the present application is as follows:

[0007] The present application provides a coal gangue roadbed material, which comprises the following components by weight:

[0008] 60 parts of modified coal gangue, 15-20 parts of portland cement, 20-30 parts of medium sand, 8-10 parts of petalite, 2-4 parts of water reducing agent, and 20-30 parts of water;

[0009] The raw materials of the modified coal gangue include coal gangue and water-soluble yttrium salt;

[0010] The weight ratio of the coal gangue to the water-soluble yttrium salt is 10:1-2;

[0011] The preparation method of the modified coal gangue comprises the following steps:

[0012] A1, adding the water-soluble yttrium salt to water and mixing uniformly to obtain a solution;

[0013] A2, adding the coal gangue in the solution, mixing uniformly, adjusting the pH of the solution to 8-9, dispersing uniformly, concentrating, calcining, and crushing to obtain the modified coal gangue.

[0014] In the coal gangue roadbed material, the weight ratio of the coal gangue to the water-soluble yttrium salt is 10:1-2, for example, can be 10:1, 10:1.2, 10:1.4, 10:1.5, 10:1.6, 10:1.8, 10:2, preferably 10:1.5-1.8, when the weight ratio of the coal gangue to the water-soluble yttrium salt is 10:1.5-1.8, the frost durability of the coal gangue roadbed material can be further improved, and the number of freeze-thaw cycles can be increased to more than 197 times, and when the weight ratio of the coal gangue to the water-soluble yttrium salt is outside the range of 10:1.5-1.8, the improvement effect of the frost durability of the coal gangue roadbed material is slightly poor.

[0015] As a further technical solution, the water-soluble yttrium salt includes one or more of yttrium chloride, yttrium nitrate, and yttrium sulfate.

[0016] In the coal gangue roadbed material, the yttrium chloride, yttrium nitrate, and yttrium sulfate material is easy to obtain, and has good water solubility, easy to fully contact with the coal gangue, which can avoid uneven modification of the coal gangue due to poor solubility of the yttrium salt, and ensure the modification effect of the water-soluble yttrium salt on the coal gangue.

[0017] As a further technical solution, during the calcination, the temperature is 600-650℃, for example, can be 600℃, 610℃, 620℃, 630℃, 640℃, 650℃, preferably 600℃, 650℃, more preferably 650℃, and the time is 1-2h, for example, can be 1h, 1.2h, 1.4h, 1.5h, 1.6h, 1.8h, 2h, preferably 1h, 2h, more preferably 1h.

[0018] As a further technical solution, when the pH of the solution is adjusted to 8-9, an ammonia water solution is added, and the mass fraction of the ammonia water solution is 10%-20%, for example, can be 10%, 12%, 15%, 16%, 18%, 20%, preferably 10%, 15%, 20%, more preferably 15%.

[0019] As a further technical solution, the raw material of the modified coal gangue further includes an epoxy-modified organic silicone resin emulsion.

[0020] In the present application, the raw material of the modified coal gangue further comprises an epoxy-modified organic silicon resin emulsion, the epoxy-modified organic silicon resin emulsion is an epoxy-modified methylphenyl organic silicon resin, a conventional amine curing agent can be used to realize room temperature self-drying, after the coal gangue is pre-modified by using a water-soluble yttrium salt, the pre-modified coal gangue is further cured and coated by using the epoxy-modified organic silicon resin emulsion, a polymer film layer can be formed on the surface of the pre-modified coal gangue, the hydrophobicity of the pre-modified coal gangue is ensured, and the combination of the coal gangue and other components in the roadbed material can be further enhanced, which is beneficial to improving the compressive strength of the coal gangue roadbed material.

[0021] As a further technical solution, the weight ratio of the coal gangue and the epoxy-modified organic silicon resin emulsion is 10:0.8-1.5, for example, it can be 10:0.8, 10:0.9, 10:1, 10:1.1, 10:1.2, 10:1.3, 10:1.4, 10:1.5, and preferably 10:1-1.3.

[0022] In the present application, when the weight ratio of the coal gangue and the epoxy-modified organic silicon resin emulsion is 10:1-1.3, the compressive strength of the coal gangue roadbed material can be further improved, and the compressive strength of the coal gangue roadbed material block-shaped test piece after maintenance for 28 days can be increased to 60.3-61.1 MPa.

[0023] As a further technical solution, the preparation method of the modified coal gangue comprises the following steps:

[0024] B1, the water-soluble yttrium salt is added to water and mixed uniformly to obtain a solution;

[0025] B2, the coal gangue is added to the solution, mixed uniformly, the pH of the solution is adjusted to 8-9, dispersed uniformly, concentrated, calcined, and pulverized to obtain pre-modified coal gangue;

[0026] B3, the epoxy-modified organic silicon resin emulsion and the pre-modified coal gangue are mixed uniformly, cured, and pulverized to obtain the modified coal gangue.

[0027] As a further technical solution, the particle size of the modified coal gangue is 30-45 μm, for example, it can be 30 μm, 32 μm, 35 μm, 38 μm, 40 μm, 42 μm, 45 μm, and preferably 45 μm.

[0028] As a further technical solution, the medium sand comprises one or both of quartz sand and basalt medium sand, and preferably basalt medium sand.

[0029] As a further technical solution, the water reducing agent comprises one or both of polycarboxylic acid water reducing agent and lignin sulfonate water reducing agent.

[0030] In the present application, the addition of water reducing agent can reduce the amount of water used in the mixing process of coal gangue roadbed material. The water reducing agent can be any water reducing agent in the art, such as polycarboxylic acid water reducing agent, lignosulfonate water reducing agent, wherein the lignosulfonate water reducing agent can be sodium lignosulfonate or calcium lignosulfonate, preferably sodium lignosulfonate.

[0031] The present application provides a preparation method of coal gangue roadbed material. The preparation method comprises the following steps: mixing the remaining components except for the water reducing agent, adding the water reducing agent, and mixing and stirring to obtain the coal gangue roadbed material.

[0032] The working principle and beneficial effects of the present application are as follows:

[0033] In the present application, the coal gangue is modified by water-soluble yttrium salt to obtain modified coal gangue, which can effectively improve the frost resistance and durability of the coal gangue roadbed material. The water absorption characteristics of coal gangue make the coal gangue roadbed material have poor frost resistance and durability. In order to reduce the water absorption performance of coal gangue, water-soluble yttrium salt is used to modify the coal gangue. Through co-precipitation and calcination, yttrium-containing oxide is formed on the surface of the coal gangue. At the same time, part of the water-soluble yttrium salt penetrates into the small pores of the coal gangue due to its water absorption characteristics. After calcination, the yttrium-containing oxide partially fills the pores of the coal gangue. Therefore, the yttrium-containing oxide formed on the surface and in the pores of the coal gangue makes its structure more compact and stable, which reduces the water absorption rate of the coal gangue to a certain extent and reduces the generation of frost heaving stress in the coal gangue. When the coal gangue is used as a base material in roadbed material, it can effectively improve the frost resistance and durability of the coal gangue roadbed material. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0035] In the following examples and comparative examples, the average particle size of the coal gangue is 45 µm; the silicate cement is PO42.5; the average particle size of the basaltic sand is 0.5 mm; the average particle size of the petalite is 80 µm; the water reducing agent is sodium lignosulfonate with an effective ingredient content of 95%; the type of the epoxy-modified silicone resin emulsion is SH-9607, the epoxy value is 0.06-0.16, and the solid content is 50%, which is purchased from Hubei Longsheng Sihai New Material Co., Ltd., and ethylenediamine curing agent is used for curing; the type of the styrene-acrylic emulsion is S-01, and the solid content is 50%.

[0036] Embodiment 1

[0037] The preparation method of the modified coal gangue comprises the following steps:

[0038] A1, 6 parts of yttrium chloride are added into 100 parts of water, mixed uniformly to obtain a solution;

[0039] A2, 60 parts of coal gangue are added into the solution, mixed uniformly, a 10% ammonia water solution is used to adjust the pH value to 8, uniformly dispersed, concentrated, calcined at 600 DEG C for 2h, crushed to obtain modified coal gangue with a particle size of 45um;

[0040] A preparation method of a coal gangue roadbed material comprises the following steps: 60 parts of modified coal gangue, 15 parts of Portland cement, 20 parts of basalt medium sand, 8 parts of petalite and 20 parts of water are uniformly mixed, then 2 parts of sodium lignosulfonate are added and mixed and stirred to obtain the coal gangue roadbed material.

[0041] Embodiment 2

[0042] The preparation method of the modified coal gangue comprises the following steps:

[0043] A1, 8.4 parts of yttrium sulfate are added into 100 parts of water, mixed uniformly to obtain a solution;

[0044] A2, 60 parts of coal gangue are added into the solution, mixed uniformly, a 15% ammonia water solution is used to adjust the pH value to 9, uniformly dispersed, concentrated, calcined at 650 DEG C for 1h, crushed to obtain modified coal gangue with a particle size of 45um;

[0045] A preparation method of a coal gangue roadbed material comprises the following steps: 60 parts of modified coal gangue, 18 parts of Portland cement, 25 parts of basalt medium sand, 9 parts of petalite and 25 parts of water are uniformly mixed, then 3 parts of sodium lignosulfonate are added and mixed and stirred to obtain the coal gangue roadbed material.

[0046] Embodiment 3

[0047] The preparation method of the modified coal gangue comprises the following steps:

[0048] A1, 12 parts of yttrium nitrate are added into 100 parts of water, mixed uniformly to obtain a solution;

[0049] A2, 60 parts of coal gangue are added into the solution, mixed uniformly, a 20% ammonia water solution is used to adjust the pH value to 9, uniformly dispersed, concentrated, calcined at 650 DEG C for 1h, crushed to obtain modified coal gangue with a particle size of 45um;

[0050] A preparation method of a coal gangue roadbed material, comprising the following steps: 60 parts of modified coal gangue, 20 parts of Portland cement, 30 parts of basalt medium sand, 10 parts of petalite and 30 parts of water are uniformly mixed, then 4 parts of sodium lignosulfonate is added, and mixing and stirring are performed, so as to obtain the coal gangue roadbed material.

[0051] Example 4

[0052] The difference between the embodiment and example 2 is that, in the preparation method of the modified coal gangue of the embodiment, 8.4 parts of yttrium sulfate is replaced by 12 parts of yttrium sulfate.

[0053] Example 5

[0054] The difference between the embodiment and example 2 is that, in the preparation method of the modified coal gangue of the embodiment, 8.4 parts of yttrium sulfate is replaced by 10.8 parts of yttrium sulfate.

[0055] Example 6

[0056] The difference between the embodiment and example 2 is that, in the preparation method of the modified coal gangue of the embodiment, 8.4 parts of yttrium sulfate is replaced by 9 parts of yttrium sulfate.

[0057] Example 7

[0058] The difference between the embodiment and example 6 is that, in the preparation method of the modified coal gangue of the embodiment, the preparation method is different, specifically as follows:

[0059] B1, 8.4 parts of yttrium sulfate is added into 100 parts of water, and uniformly mixed to obtain a solution;

[0060] B2, 60 parts of coal gangue is added into the solution, and uniformly mixed, then the pH value is adjusted to 9 by using an ammonia water solution with a mass fraction of 15%, and uniformly dispersed, concentrated, calcined at 650 DEG C for 1h, crushed to obtain pre-modified coal gangue;

[0061] B3, 4.8 parts of epoxy modified organosilicon resin emulsion and the pre-modified coal gangue are uniformly mixed, cured, and crushed to obtain modified coal gangue with a particle size of 45 mu m.

[0062] Example 8

[0063] The difference between the embodiment and example 7 is that, in the preparation method of the modified coal gangue of the embodiment, 4.8 parts of epoxy modified organosilicon resin emulsion is replaced by 6 parts of epoxy modified organosilicon resin emulsion.

[0064] Example 9

[0065] The difference between the embodiment and example 7 is that, in the preparation method of the modified coal gangue of the embodiment, 4.8 parts of epoxy modified organosilicon resin emulsion is replaced by 7.8 parts of epoxy modified organosilicon resin emulsion.

[0066] Example 10

[0067] The difference between this example and Example 7 is that in the preparation method of the modified coal gangue of this example, 4.8 parts of the epoxy-modified silicone resin emulsion is replaced by 9 parts of the epoxy-modified silicone resin emulsion.

[0068] Example 11

[0069] The difference between this example and Example 10 is that in the preparation method of the modified coal gangue of this example, the epoxy-modified silicone resin emulsion is replaced by an equal amount of a styrene-acrylic emulsion.

[0070] Comparative Example 1

[0071] The difference between this comparative example and Example 2 is that in this comparative example, the modified coal gangue is replaced by an equal amount of coal gangue.

[0072] Comparative Example 2

[0073] The difference between this comparative example and Example 2 is that the preparation method of the coal gangue subgrade material in this comparative example is different, specifically: 60 parts of coal gangue, 8.4 parts of yttrium sulfate, 18 parts of Portland cement, 25 parts of basalt medium sand, 9 parts of petalite, and 25 parts of water are uniformly mixed, then 3 parts of sodium lignosulfonate is added and mixed and stirred to obtain the coal gangue subgrade material.

[0074] Comparative Example 3

[0075] The difference between this comparative example and Example 2 is that the preparation method of the coal gangue subgrade material in this comparative example is different, specifically: 60 parts of coal gangue, 8.4 parts of yttrium oxide, 18 parts of Portland cement, 25 parts of basalt medium sand, 9 parts of petalite, and 25 parts of water are uniformly mixed, then 3 parts of sodium lignosulfonate is added and mixed and stirred to obtain the coal gangue subgrade material.

[0076] Comparative Example 4

[0077] The difference between this comparative example and Example 2 is that the preparation method of the modified coal gangue in this comparative example is different, specifically:

[0078] 8.4 parts of the epoxy-modified silicone resin emulsion and 60 parts of coal gangue are uniformly mixed, cured, and pulverized to obtain modified coal gangue with a particle size of 45 μm.

[0079] Experimental Example 1

[0080] After the coal gangue subgrade materials of Examples 1-11 and Comparative Examples 1-4 are prepared into cylindrical test pieces, they are cured according to the method in JTG3441-2024 "Test Code for Inorganic Stabilized Materials of Highway Engineering", after a curing period of 28 days, the freeze-thaw cycle number is determined, and the freeze-thaw cycle number at which the test sample begins to crack or peel is recorded, wherein the greater the freeze-thaw cycle number, the better the frost durability, the diameter-height ratio of the test piece is 1:1, the size is 150mmx150mm, and the test temperature is-18℃, and the test results are shown in Table 1.

[0081] Table 1: Freeze-thaw cycle number test results of Examples 1-11 and Comparative Examples 1-4

[0082]

[0083] As can be seen from Table 1, compared with Comparative Examples 1-4, the freeze-thaw cycle number of the coal gangue subgrade material prepared by Examples 1-6 is significantly improved, indicating that the coal gangue is modified by the water-soluble yttrium salt, which can effectively improve the frost durability of the coal gangue subgrade material.

[0084] Experimental Example 2

[0085] The coal gangue subgrade materials prepared by Examples 6-11 are prepared into block-shaped test pieces, and cured according to the curing method in GB / T 50081-2019 "Standard Test Methods for Physical and Mechanical Properties of Concrete", the curing period is 28 days, and the compressive strength of the coal gangue subgrade material test piece is tested according to the test method in GB / T 50081-2019 "Standard Test Methods for Physical and Mechanical Properties of Concrete", wherein the loading speed is 0.5MPa / s during testing, the test piece size is 150mmx150mmx150mm, each group of test pieces is 3 pieces, and the test results are the average of the test results of 3 test pieces, and the test results are shown in Table 2.

[0086] Table 2: Compressive strength test results of Examples 6-11

[0087]

[0088] As can be seen from Table 2, compared with Examples 6 and 11, the 28d compressive strength of the coal gangue subgrade material of Examples 7-10 is improved, indicating that when the raw material of the modified coal gangue also includes an epoxy modified silicone resin emulsion, the coal gangue is modified by the epoxy modified silicone resin emulsion and the water-soluble yttrium salt, which can improve the compressive strength of the coal gangue subgrade material to a certain extent.

[0089] The above is only a preferred embodiment of the present application, and is not intended to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A coal gangue roadbed material, characterized in that, Comprise the following components by weight parts: Modified coal gangue 60 parts, Portland cement 15~20 parts, medium sand 20~30 parts, petalite 8~10 parts, water reducing agent 2~4 parts, water 20~30 parts; The raw material of the modified coal gangue comprises coal gangue and water-soluble yttrium salt; The weight ratio of the coal gangue to the water-soluble yttrium salt is 10:1~2; The preparation method of the modified coal gangue comprises the following steps: A1, the water-soluble yttrium salt is added to water, mixed uniformly, and a solution is obtained; A2, the coal gangue is added to the solution, mixed uniformly, the pH of the solution is adjusted to 8~9, uniformly dispersed, concentrated, calcined, and crushed to obtain the modified coal gangue.

2. The coal gangue roadbed material according to claim 1, characterized in that, The water-soluble yttrium salt comprises one or more of yttrium chloride, yttrium nitrate and yttrium sulfate.

3. The coal gangue roadbed material according to claim 1, characterized in that, When the pH of the solution is adjusted to 8~9, an ammonia solution is added, and the mass fraction of the ammonia solution is 10%~20%.

4. The coal gangue roadbed material according to claim 1, characterized in that, When calcining, the temperature is 600~650℃, and the time is 1~2h.

5. The coal gangue roadbed material according to claim 1, characterized in that, The raw material of the modified coal gangue further comprises an epoxy modified silicone resin emulsion.

6. The coal gangue roadbed material according to claim 5, characterized in that, The weight ratio of the coal gangue to the epoxy modified silicone resin emulsion is 10:0.8~1.

5.

7. The coal gangue roadbed material according to claim 5, characterized in that, The preparation method of the modified coal gangue comprises the following steps: B1, the water-soluble yttrium salt is added to water, mixed uniformly, and a solution is obtained; B2, the coal gangue is added to the solution, mixed uniformly, the pH of the solution is adjusted to 8~9, uniformly dispersed, concentrated, calcined, and crushed to obtain the pre-modified coal gangue; B3, the epoxy modified silicone resin emulsion and the pre-modified coal gangue are mixed uniformly, solidified, and crushed to obtain the modified coal gangue.

8. The coal gangue roadbed material according to claim 1, characterized in that, The medium sand comprises one or both of quartz sand and basalt medium sand.

9. The coal waste road base material according to claim 1, wherein, The water reducing agent comprises one or both of polycarboxylic acid water reducing agent and lignosulfonate water reducing agent.

10. A method for preparing a coal gangue roadbed material, for preparing a coal gangue roadbed material as claimed in any one of claims 1 to 9, characterized in that, Comprise the following steps: After the remaining components except the water reducing agent are uniformly mixed, the water reducing agent is added, mixed and stirred to obtain the coal gangue roadbed material.

Images