A self-igniting coal gangue-based plastering mortar and a preparation method thereof
By combining cement and self-igniting coal gangue with particle size distribution design, and using water-retaining agents, the problem of insufficient compressive strength of self-igniting coal gangue-based plastering mortar was solved, and self-igniting coal gangue-based plastering mortar with high compressive strength and low consistency loss was prepared.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA HUAYE GROUP
- Filing Date
- 2026-04-22
- Publication Date
- 2026-06-05
AI Technical Summary
The compressive strength of self-igniting coal gangue-based plastering mortar is insufficient, which leads to easy cracking, hollowing, and detachment of the wall base layer, making it difficult to meet the construction quality and long-term application requirements of building plastering projects.
Cement and self-combusting coal gangue with a particle size of 0μm to 75μm were used as a cementitious material. The preparation method of self-combusting coal gangue-based plastering mortar was optimized by designing the gradation of self-combusting coal gangue with different particle sizes and by using hydroxypropyl methylcellulose ether and polycarboxylate superplasticizer.
It significantly improved the compressive strength and overall density of self-igniting coal gangue-based plastering mortar, reduced the consistency loss rate, and improved construction quality and long-term stability.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of building materials technology, specifically to a self-igniting coal gangue-based plastering mortar and its preparation method. Background Technology
[0002] Spontaneously combusting coal gangue is a solid waste generated during coal mining and washing, which, after long-term accumulation, spontaneously combusts under natural conditions. However, with the development of the coal industry, the amount of spontaneously combusting coal gangue stockpiled has been increasing year by year, not only occupying land resources but also posing safety hazards.
[0003] In recent years, utilizing industrial solid waste to replace traditional building materials has not only met the requirements of green and low-carbon development but also reduced engineering material costs. Self-combusting coal gangue, after combustion, exhibits increased activity and possesses certain pozzolanic reaction potential, making it suitable as an auxiliary cementitious material. Its hardness also allows it to be used as fine aggregate in mortar. However, self-combusting coal gangue-based plastering mortar generally suffers from insufficient compressive strength. Under the bonding stress of the wall substrate and long-term structural loads, problems such as cracking, hollowing, and detachment of the plaster layer easily occur, making it difficult to meet the construction quality and long-term application requirements of building plastering projects. Therefore, developing a high-compressive-strength self-combusting coal gangue-based plastering mortar is of great significance. Summary of the Invention
[0004] This invention proposes a self-igniting coal gangue-based plastering mortar and its preparation method, which solves the problem of insufficient compressive strength of self-igniting coal gangue-based plastering mortar in related technologies.
[0005] The technical solution of the present invention is as follows: This invention proposes a self-igniting coal gangue-based plastering mortar, comprising the following raw materials in parts by weight: 300 parts of cementitious material, 1200-1300 parts of self-igniting coal gangue, 360-380 parts of water, 4-6 parts of water-reducing agent, and 0.1-0.5 parts of water-retaining agent; The cementing material includes cement and self-igniting coal gangue with a particle size of 0μm < and 75μm. The self-igniting coal gangue comprises the following components by weight: 15-25 parts of self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm, 60-75 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm, and 10-15 parts of self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm.
[0006] As a further technical solution, the average specific surface area of the self-combusting coal gangue with a particle size of 0μm < ≤ 75μm is 380~400kg / m². 3 .
[0007] As a further technical solution, the mass ratio of the cement to the self-igniting coal gangue is 18:1~3.
[0008] As a further technical solution, the water-retaining agent includes one or both of hydroxypropyl methylcellulose ether and methylcellulose ether.
[0009] As a further technical solution, the water-retaining agent is hydroxypropyl methylcellulose ether.
[0010] As a further technical solution, the viscosity of the hydroxypropyl methylcellulose ether is 200,000 mPa·s.
[0011] As a further technical solution, the mass of the water-retaining agent is 0.05% to 0.15% of the mass of the cementitious material.
[0012] As a further technical solution, the cement is silicate cement.
[0013] As a further technical solution, the water-reducing agent is a polycarboxylate water-reducing agent.
[0014] The present invention also proposes a method for preparing self-igniting coal gangue-based plastering mortar, comprising the following steps: mixing the cementitious material, self-igniting coal gangue, water and water-retaining agent, and then adding a water-reducing agent to mix, thereby obtaining the self-igniting coal gangue-based plastering mortar.
[0015] This invention first mixes the raw materials except for the water-reducing agent, and then adds the water-reducing agent, so that the mortar not only has a small consistency loss rate, but also good compressive strength. The reason is that this method can first generate a water film on the surface of cement particles, thereby reducing the surface energy of cement particles, reducing the adsorption of water-reducing agent by C3A mineral in cement, increasing the concentration of water-reducing agent in the solution, and reducing the loss of mortar consistency.
[0016] The working principle and beneficial effects of this invention are as follows: In this invention, the cementitious material is a mixture of cement and self-combusting coal gangue with a particle size of 0μm to 75μm, which improves the compressive strength of the self-combusting coal gangue-based plastering mortar. The self-combusting coal gangue with a particle size of 0μm to 75μm can fill the gaps in the cement hydration products, reducing the porosity defects inside the cementitious matrix. At the same time, it can undergo a secondary hydration reaction to generate calcium silicate gel under the activation of calcium hydroxide produced by cement hydration, thereby improving the overall bonding strength of the cementitious system and thus improving the compressive strength of the self-combusting coal gangue-based plastering mortar.
[0017] This invention improves the compressive strength of self-igniting coal gangue-based plastering mortar by limiting the weight composition of self-igniting coal gangue with different particle sizes. The reason is that this gradient gradation allows self-igniting coal gangue of different particle sizes to form a compact packing structure. Self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm constitutes the skeleton structure of the mortar, self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm fills the gaps between the skeleton structures, and self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm further fills the remaining fine gaps, reducing the porosity inside the mortar, improving the overall density of the mortar, and thus improving the compressive strength of the self-igniting coal gangue-based plastering mortar. Detailed Implementation
[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0019] In the following examples and comparative examples: The spontaneously combusting coal gangue came from a mining area in Handan City; Self-igniting coal gangue: The test was conducted on self-igniting coal gangue from a mining area in Handan City. After crushing, screening and grading, fine aggregate with a particle size of 0~4.75mm was obtained. The fineness modulus after gradation was 2.4, which is classified as medium sand. The chemical composition is shown in Table 1, in which SiO2, Al2O3 and Fe2O3 are the main components. The physical properties of the fine aggregate of self-igniting coal gangue are shown in Table 2. Table 1 Chemical composition of spontaneously combusting coal gangue
[0020] Table 2 Physical properties of self-igniting coal gangue fine aggregate
[0021] Self-igniting coal gangue with a particle size of 0μm to 75μm: The self-igniting coal gangue with a particle size of 0μm to 75μm used in the experiment was a byproduct generated during the crushing of self-igniting coal gangue to prepare fine aggregate. The collected self-igniting coal gangue was then sieved through a 75µm square-hole sieve to obtain the self-igniting coal gangue with a particle size of 0μm to 75μm used in the experiment, with an average specific surface area of 390m². 2 / kg; various performance indicators are shown in Table 3; Table 3. Basic properties of self-igniting coal gangue powder with particle size ≤ 75 μm and 0 μm.
[0022] The cement is PO 42.5 type Portland cement; The polycarboxylate superplasticizer was obtained by mixing the CF710 polycarboxylate superplasticizer mother liquor (purchased from Zhongyan Building Materials Technology Co., Ltd.) with water at a ratio of 1:4. Methylcellulose ether, model: M450, purchased from Shijiazhuang Yusong Building Materials Technology Co., Ltd. Hydroxypropyl methylcellulose ether, with a viscosity of 200,000 mPa·s, was purchased from Shijiazhuang Yusong Building Materials Technology Co., Ltd.
[0023] Example 1 A method for preparing self-combusting coal gangue-based plastering mortar includes the following steps: 300 parts of cementitious material, 1200 parts of self-igniting coal gangue, 360 parts of water and 0.1 parts of hydroxypropyl methylcellulose ether were mixed for 100 seconds, and then 4 parts of polycarboxylate superplasticizer were added and mixed for 50 seconds to obtain self-igniting coal gangue-based plastering mortar. The cementitious material consisted of cement and self-igniting coal gangue with a mass ratio of 18:1 and a particle size of 0μm to 75μm. The self-igniting coal gangue comprises the following components by weight: 15 parts of self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm, 75 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm, and 10 parts of self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm.
[0024] Example 2 A method for preparing self-combusting coal gangue-based plastering mortar includes the following steps: 300 parts of cementitious material, 1250 parts of self-igniting coal gangue, 370 parts of water and 0.3 parts of hydroxypropyl methylcellulose ether were mixed for 120 seconds, and then 5 parts of polycarboxylate superplasticizer were added and mixed for 60 seconds to obtain self-igniting coal gangue-based plastering mortar. The cementitious material was composed of cement and self-igniting coal gangue with a mass ratio of 18:1 and a particle size of 0μm to 75μm. The self-igniting coal gangue comprises the following components by weight: 15 parts of self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm, 75 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm, and 10 parts of self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm.
[0025] Example 3 A method for preparing self-combusting coal gangue-based plastering mortar includes the following steps: 300 parts of cementitious material, 1300 parts of self-igniting coal gangue, 380 parts of water and 0.5 parts of hydroxypropyl methylcellulose ether were mixed for 130 seconds, and then 6 parts of polycarboxylate superplasticizer were added and mixed for 70 seconds to obtain self-igniting coal gangue-based plastering mortar. The cementitious material consisted of cement and self-igniting coal gangue with a mass ratio of 18:1 and a particle size of 0μm to 75μm. The self-igniting coal gangue comprises the following components by weight: 15 parts of self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm, 75 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm, and 10 parts of self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm.
[0026] Example 4 The only difference between this embodiment and Embodiment 2 is that the self-igniting coal gangue in this embodiment includes the following components by weight: 25 parts of self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm, 60 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm, and 15 parts of self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm.
[0027] Example 5 The only difference between this embodiment and Embodiment 2 is that the self-igniting coal gangue in this embodiment includes the following components by weight: 20 parts of self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm, 68 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm, and 12 parts of self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm.
[0028] Example 6 The only difference between this embodiment and Embodiment 2 is that the cementitious material in this embodiment is composed of cement with a mass ratio of 18:2 and self-igniting coal gangue with a particle size of 0μm < ≤ 75μm.
[0029] Example 7 The only difference between this embodiment and Embodiment 2 is that the cementitious material in this embodiment is composed of cement in a mass ratio of 6:1 and self-igniting coal gangue with a particle size of 0μm < ≤ 75μm.
[0030] Example 8 The only difference between this embodiment and Embodiment 2 is that the cementing material in this embodiment is cement.
[0031] Example 9 A method for preparing self-combusting coal gangue-based plastering mortar includes the following steps: 300 parts of cementitious material, 1250 parts of self-igniting coal gangue, 370 parts of water, 0.3 parts of hydroxypropyl methylcellulose ether and 5 parts of polycarboxylate superplasticizer were mixed for 180 seconds to obtain self-igniting coal gangue-based plastering mortar. The cementitious material consisted of cement and self-igniting coal gangue with a mass ratio of 18:1 and a particle size of 0μm to 75μm. The self-igniting coal gangue comprises the following components by weight: 15 parts of self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm, 75 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm, and 10 parts of self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm.
[0032] Example 10 A method for preparing self-combusting coal gangue-based plastering mortar includes the following steps: 1250 parts of self-igniting coal gangue, 0.3 parts of hydroxypropyl methylcellulose ether and 185 parts of water were mixed for 60 seconds. Then, 300 parts of cementitious material were added and mixed for 60 seconds. Finally, 5 parts of polycarboxylate superplasticizer and 185 parts of water were added and mixed for 60 seconds to obtain self-igniting coal gangue-based plastering mortar. The cementitious material consisted of cement and self-igniting coal gangue with a mass ratio of 18:1 and a particle size of 0μm to 75μm. The self-igniting coal gangue comprises the following components by weight: 15 parts of self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm, 75 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm, and 10 parts of self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm.
[0033] Example 11 A method for preparing self-combusting coal gangue-based plastering mortar includes the following steps: 300 parts of cementitious material, 1250 parts of self-combusting coal gangue, 370 parts of water, 0.3 parts of hydroxypropyl methylcellulose ether and 3.5 parts of polycarboxylate superplasticizer were mixed for 120 seconds, and then 1.5 parts of polycarboxylate superplasticizer were added and mixed for 60 seconds to obtain self-combusting coal gangue-based plastering mortar. The cementitious material consisted of cement and self-combusting coal gangue with a mass ratio of 18:1 and a particle size of 0μm to 75μm. The self-igniting coal gangue comprises the following components by weight: 15 parts of self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm, 75 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm, and 10 parts of self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm.
[0034] Comparative Example 1 The only difference between this comparative example and Example 2 is that the self-igniting coal gangue in this comparative example includes the following components by weight: 90 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm and 10 parts of self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm.
[0035] Comparative Example 2 The only difference between this comparative example and Example 2 is that the self-igniting coal gangue in this comparative example includes the following components by weight: 15 parts of self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm and 85 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm.
[0036] Test case The self-igniting coal gangue-based plastering mortars prepared in Examples 1-11 and Comparative Examples 1-2 were tested according to the following method: 1. Compressive strength: The test was conducted according to the test method specified in standard JGJ / T 70-2009 "Standard for Test Methods of Basic Performance of Building Mortar". The cubic specimen size used in the test was 70.7mm×70.7mm×70.7mm, the test temperature was 20℃, the relative humidity was 95%, and the loading rate was 0.5KN / s. The test results are shown in Tables 4, 5, and 6 below. 2. Tensile bond strength: The test was conducted according to the test method specified in standard JGJ / T 70-2009 "Standard for Test Methods of Basic Performance of Building Mortar". The cubic specimen size used in the test was 70mm×70mm×20mm, the test temperature was 20℃, the test relative humidity was 50%, and the loading rate was 0.5mm / min. The test results are shown in Table 5 below. 3. Consistency test: The test was conducted according to the test method specified in standard JGJ / T 70-2009 "Standard for Test Methods of Basic Performance of Building Mortar". The test results are shown in Table 6 below.
[0037] Table 4. Performance test results of self-igniting coal gangue-based plastering mortar in Examples 1-5 and Comparative Examples 1-2
[0038] The 7-day and 28-day compressive strengths of Examples 1-5 are all greater than those of Comparative Examples 1-2, indicating that the present invention improves the compressive strength of self-igniting coal gangue-based plastering mortar by grading self-igniting coal gangue with different particle sizes.
[0039] Table 5. Performance test results of self-igniting coal gangue-based plastering mortar in Examples 2 and 6-8
[0040] The 7-day compressive strength, 28-day compressive strength, and tensile bond strength of Examples 2 and 6-7 are all greater than those of Example 8, indicating that the present invention improves the compressive strength of self-combusting coal gangue-based plastering mortar by adding cement and self-combusting coal gangue as cementing materials.
[0041] Table 6. Performance test results of self-igniting coal gangue-based plastering mortar in Examples 2 and 9-11
[0042] The consistency loss rate of Example 2 was lower than that of Examples 9-11, and the 7-day compressive strength and 28-day compressive strength of Example 2 were both greater than those of Examples 9-11. This indicates that the present invention reduces the consistency loss rate of self-igniting coal gangue-based plastering mortar and improves the compressive strength of self-igniting coal gangue-based plastering mortar by first mixing with other raw materials and then adding water-reducing agent.
[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A self-igniting coal gangue-based plastering mortar, characterized in that, The raw materials include the following components by weight: 300 parts of cementitious material, 1200-1300 parts of self-combusting coal gangue, 360-380 parts of water, 4-6 parts of water-reducing agent, and 0.1-0.5 parts of water-retaining agent; The cementing material includes cement and self-igniting coal gangue with a particle size of 0μm < and 75μm. The self-igniting coal gangue comprises the following components by weight: 15-25 parts of self-igniting coal gangue with a particle size of 0.1mm ≤ 0.5mm, 60-75 parts of self-igniting coal gangue with a particle size of 0.5mm ≤ 2.36mm, and 10-15 parts of self-igniting coal gangue with a particle size of 2.36mm ≤ 4.75mm.
2. The self-igniting coal gangue-based plastering mortar according to claim 1, characterized in that, The average specific surface area of the self-igniting coal gangue with a particle size of 0μm to 75μm is 380~400 kg / m³. 3 .
3. The self-igniting coal gangue-based plastering mortar according to claim 1, characterized in that, The mass ratio of cement to self-igniting coal gangue is 18:1~3.
4. The self-igniting coal gangue-based plastering mortar according to claim 1, characterized in that, The water-retaining agent includes one or both of hydroxypropyl methylcellulose ether and methylcellulose ether.
5. The self-igniting coal gangue-based plastering mortar according to claim 4, characterized in that, The water-retaining agent is hydroxypropyl methylcellulose ether.
6. The self-igniting coal gangue-based plastering mortar according to claim 5, characterized in that, The viscosity of the hydroxypropyl methylcellulose ether is 200,000 mPa·s.
7. The self-igniting coal gangue-based plastering mortar according to claim 1, characterized in that, The water-retaining agent is 0.05% to 0.15% of the mass of the cementitious material.
8. The self-igniting coal gangue-based plastering mortar according to claim 1, characterized in that, The cement is silicate cement.
9. The self-igniting coal gangue-based plastering mortar according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent.
10. A method for preparing a self-igniting coal gangue-based plastering mortar, used to prepare the self-igniting coal gangue-based plastering mortar according to any one of claims 1 to 9, characterized in that, Includes the following steps: The cementitious material, self-igniting coal gangue, water and water-retaining agent are mixed, and then a water-reducing agent is added and mixed to obtain the self-igniting coal gangue-based plastering mortar.