Mining inorganic rapid-hardening jet composite mortar

Abstract

The invention discloses mineral inorganic quick-setting jet composite mortar, which comprises a formula of mortar and a manufacturing process of the composite mortar, the formula of the mortar comprises 60% of river sand, coarse sand with the specification of FM of 3.7-3.1, medium sand with the specification of FM of 3.0-2.3, fine sand with the specification of FM of 2.2-1.6 and superfine sand with the specification of FM of 1.5-0.7, and the raw materials are proportioned and respectively account for 15%; the formula of the composite mortar comprises 60% of river sand with the specification of FM of 3.7-3.1, 15% of medium sand with the specification of FM of 3.0-2.3, 15% of fine sand with the specification of FM of 2.2-1.6 and 15% of superfine sand with the specification of FM of 1.5-0.7; the Portland cement P425 accounts for 21%; the fly ash accounts for 6%; the accelerator accounts for 5%; the retarding, anti-cracking and flexible agent composite material accounts for 8%; and on-site stirring is not needed, so that the number of workers required by manual batching and stirring is greatly reduced, the labor intensity is reduced, and the construction efficiency is improved. Flying dust generated by on-site manual stirring is avoided, the working environment of workers is remarkably improved, and the body health of the workers is guaranteed. In the formula, large-particle stones are removed, and the fly ash, the accelerator and other components are comprehensively applied, so that the injection rebound rate is reduced to 5% or below from traditional 30% or above, the material waste is reduced, and the construction cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of construction and support in coal mines or non - coal mines, and particularly relates to a kind of inorganic quick - setting sprayed composite mortar for mines. Background Art

[0002] In the construction of coal mines or non - coal mines and various related projects, shotcrete support or reinforcement technology is widely used, mainly for surface isolation sealing or reinforcement of mining areas, tunnels, bridges, roads, slopes, etc. At present, the shotcrete materials used in traditional shotcreting operations usually consist of stones, river sand, cement and setting agents, which need to be manually mixed at the construction site and then sprayed by a shotcrete machine. This operation mode has many problems. The existence of a large number of stones in the existing shotcrete materials makes the rebound rate as high as 30% during shotcreting, which not only causes material waste but also increases the construction cost. The on - site manual batching and mixing have uncertainties, and the properties such as the strength of the slurry cannot be timely inspected on site, resulting in unstable shotcrete strength and difficulty in meeting the project requirements. The process of manual batching and mixing requires the participation of more personnel, with a high labor intensity, which is not conducive to improving the construction efficiency. The on - site manual mixing will generate a large amount of dust, seriously polluting the working environment and endangering the health of workers. Due to a large number of labor employments and a high rebound rate, the shotcrete cost remains high, the construction efficiency is low, and the overall construction effect is poor. Therefore, in view of the above deficiencies, the present invention proposes a kind of inorganic quick - setting sprayed composite mortar for mines. Summary of the Invention

[0003] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art. Without on - site mixing, it greatly reduces the number of personnel required for manual batching and mixing, reduces the labor intensity, and improves the construction efficiency. It avoids the dust generated by on - site manual mixing, significantly improves the working environment of workers, and is conducive to protecting the health of workers. The large - particle stones are removed from the formula, and components such as fly ash and quick - setting agents are comprehensively applied, reducing the shotcrete rebound rate from more than 30% in the traditional case to less than 5%, reducing material waste and construction costs.

[0004] The industrial production in factories ensures the uniformity of the slurry, and each formula has been pre - tested and verified, making the mortar have a high and stable strength grade, which can significantly reduce the thickness of shotcrete and improve the project quality.

[0005] The slurry of this formula can achieve stable transportation over a long distance, greatly reducing the number of movements of the shotcrete machine and further improving the construction efficiency. The improvement of shotcrete efficiency, cost reduction and construction effect make the inorganic quick - setting sprayed composite mortar for mines of the present invention have good economic and social benefits in practical applications. During the industrial production process in factories, strict records are kept on raw materials, production processes and product quality, making the shotcrete effect traceable and facilitating the monitoring and management of project quality.

[0006] The present invention also provides a kind of mine - used inorganic quick - setting spray composite mortar as described above, including the formula of the mortar and the manufacturing process of the composite mortar. The formula of the mortar includes 60% river sand. Among them, coarse sand with a specification of FM = 3.7 - 3.1, medium sand with FM = 3.0 - 2.3, fine sand with FM = 2.2 - 1.6, and extra - fine sand with FM = 1.5 - 0.7 are proportioned and each accounts for 15%; Portland cement P425 accounts for 21%; fly ash accounts for 6%; quick - setting agent accounts for 5%; retarder, crack - resistant and flexible agent composite material accounts for 8%.

[0007] The manufacturing process of the composite mortar is industrial production in a factory, which is specifically as follows:

[0008] Raw material preparation: Strictly select river sand, Portland cement P425, fly ash, quick - setting agent, and retarder, crack - resistant and flexible agent composite material that meet the quality standards, and accurately measure them according to the formula;

[0009] Mixing: Add the measured raw materials into the mixing equipment. First, mix them at a low speed of 200 revolutions per minute for 5 minutes to initially mix the raw materials evenly; then adjust to a high speed of 500 revolutions per minute and mix for 15 minutes to ensure that the raw materials are fully and evenly mixed;

[0010] Quality inspection: Conduct quality index inspections on the produced finished mortar, such as compressive strength, setting time, fluidity, rebound rate, etc. It can only be shipped out after passing the inspection.

[0011] According to a kind of mine - used inorganic quick - setting spray composite mortar provided by the present invention, during the industrial production process in the factory, the quality control of raw materials ensures that their mud content, particle shape, and grading index meet the standards; the strength, setting time, and soundness performance indicators of the Portland cement P425 need to meet the requirements.

[0012] According to a kind of mine - used inorganic quick - setting spray composite mortar provided by the present invention, the activity index, fineness, and water demand ratio of the fly ash need to comply with the regulations; the quick - setting agent ensures its initial setting time, final setting time, and strength promotion rate; the retarder, crack - resistant and flexible agent composite material ensures that its effects of retarding setting, crack - resistance, and enhancing flexibility meet the design requirements.

[0013] According to a kind of mine - used inorganic quick - setting spray composite mortar provided by the present invention, when it is necessary to adjust the strength grade of the mortar, the proportion of Portland cement P425 is increased, and the proportion of cement can be increased by 1% - 3%. At the same time, the proportion of river sand is correspondingly reduced, and the reduction range is 0.5% - 2%; when it is necessary to shorten the setting cycle, the dosage of the quick - setting agent is increased. For every 1 - 2 minutes reduction in setting time, the dosage of the quick - setting agent can be increased by 0.2% - 0.5%. At the same time, the dosage of the retarder component in the retarder, crack - resistant and flexible agent composite material is correspondingly adjusted.

[0014] According to a kind of inorganic quick-setting sprayed composite mortar for mines provided by the present invention, after replacing the gravel with fly ash, in terms of improving the cementing and hardening effects of the slurry, the specific manifestations are as follows: The reactive silica and reactive alumina in the fly ash are stimulated by the calcium hydroxide generated by the hydration of cement and undergo a secondary hydration reaction, generating a large amount of calcium silicate hydrate and calcium aluminate hydrate gels. These gels fill the pores in the mortar, making the microstructure of the mortar more dense, thereby improving the cementing strength of the slurry. At the same time, the spherical particle morphology of the fly ash can improve the fluidity of the mortar in the mortar, contributing to the uniform distribution of each component and further enhancing the hardening effect.

[0015] According to a kind of inorganic quick-setting sprayed composite mortar for mines provided by the present invention, in the construction scenarios with a dry environment and a high requirement for initial strength, the mass ratio of the quick-setting agent to the retarder component is controlled between 3:1 and 5:1 to ensure that the mortar can quickly set and reach a certain strength; in the construction scenarios with a humid environment or a long requirement for the setting time, the mass ratio of the quick-setting agent to the retarder component can be adjusted to between 1:1 and 2:1.

[0016] According to a kind of inorganic quick-setting sprayed composite mortar for mines provided by the present invention, replicate dependent claim 2. Write the beneficial effects of this claim.

[0017] Compared with the prior art, a kind of inorganic quick-setting sprayed composite mortar for mines of the present invention adopts the finished mortar material produced by factory industrialization, without on-site mixing, greatly reducing the personnel required for manual batching and mixing, reducing the labor intensity, and improving the construction efficiency. It avoids the dust generated by on-site manual mixing, significantly improves the working environment of workers, and is beneficial to protecting the physical health of workers. The large-particle gravel is removed from the formula, and components such as fly ash and quick-setting agent are comprehensively applied, reducing the spray rebound rate from more than 30% in the traditional case to less than 5%, reducing material waste and lowering the construction cost.

[0018] Compared with the prior art, a kind of inorganic quick-setting sprayed composite mortar for mines of the present invention ensures the uniformity of the slurry by factory industrialization production, and each formula has been pre-tested and verified, making the mortar have a high and stable strength grade, which can significantly reduce the thickness of the sprayed mortar and improve the project quality.

[0019] Compared with the prior art, a kind of inorganic quick-setting sprayed composite mortar for mines of the present invention

[0020] The slurry of this formulation can achieve stable transportation over extremely long distances, greatly reducing the number of movements of the shotcrete machine and further improving the construction efficiency. The improvement of the shotcrete efficiency, the reduction of costs, and the improvement of the construction effect make the inorganic rapid-setting spray composite mortar for mines of the present invention have good economic and social benefits in practical applications. During the industrial production process in the factory, strict records are kept of the raw materials, production processes, and product quality, making the shotcrete effect traceable and facilitating the monitoring and management of the project quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the drawings and embodiments;

[0022] Figure 1 is a process flow chart for the production of an inorganic rapid-setting spray composite mortar for mines of the present invention;

[0023] Figure 2 is Table 1 of the compressive strength test data for an inorganic rapid-setting spray composite mortar for mines of the present invention;

[0024] Figure 3 is Table 2 of the compressive strength test data for an inorganic rapid-setting spray composite mortar for mines of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the drawings. The role of the drawings is to supplement the description in the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be construed as a limitation on the protection scope of the present invention.

[0026] Referring to Figures 1-3 , in an embodiment of the present invention, an inorganic rapid-setting spray composite mortar for mines, the formulation of the mortar includes 60% river sand, among which the coarse sand, the specification is selected as FM = 3.7 - 3.1, the medium sand is selected as FM = 3.0 - 2.3, the fine sand is selected as FM = 2.2 - 1.6, and the extra-fine sand is selected as FM = 1.5 - 0.7, and they are proportioned and each accounts for 15%; Portland cement P425 accounts for 21%; fly ash accounts for 6%; the rapid-setting agent accounts for 5%; the composite material of retarder, crack resistance, and flexible agent accounts for 8%.

[0027] The production process of the composite mortar is industrial production in the factory, which is as follows:

[0028] Raw material preparation: According to the basic formula, prepare river sand in corresponding proportions, ensuring the accurate proportion of coarse sand, medium sand, fine sand, and extra-fine sand, as well as Portland cement P425, fly ash, accelerating agent, and composite materials of setting retarder, crack resistance, and flexibility agent. Strictly control the quality of raw materials. The river sand should meet the standards for construction sand, the cement should have the corresponding strength grade and quality certification, the activity and other indicators of fly ash should meet the requirements, and the accelerating agent and composite materials such as setting retarder, crack resistance, and flexibility agent should comply with relevant industry standards.

[0029] Industrial production process: Accurately measure various raw materials according to the formula, using high-precision measuring equipment to ensure that the measurement error is controlled within a very small range. Add the measured river sand, cement, and fly ash into a compulsory mixer in sequence. First, stir at a low speed of 200 revolutions per minute for 5 minutes to initially mix the dry raw materials evenly. Then add the accelerating agent and composite materials of setting retarder, crack resistance, and flexibility agent, and adjust the stirring speed to 500 revolutions per minute and stir at high speed for 15 minutes to ensure that all raw materials are fully mixed. After stirring, convey the composite mortar to the packaging equipment through a conveyor belt for sealed packaging of 50 kg per bag.

[0030] Quality inspection: After curing under standard curing conditions until the specified ages of 7 days and 28 days, conduct compressive strength tests. Use a penetration resistance instrument to measure the setting time of the mortar. The initial setting time should meet the construction requirements, and the final setting time should not be too long to ensure the construction progress. Measure the consistency of the mortar through a mortar consistency meter to ensure that its fluidity meets the requirements of shotcreting construction, and generally, the consistency is controlled between 80 - 120 mm. Under the conditions simulating the construction site, conduct a shotcreting test and measure the rebound rate to ensure that the rebound rate is less than 5%. Analyze unqualified products, find the reasons, such as deviation in raw material proportions and uneven mixing, and adjust and re-produce after adjustment.

[0031] Construction application: Before the bolt-shotcrete support construction in the coal mine roadway, clean the roadway surface, remove impurities such as loose stones and dust, and ensure that the spraying surface is clean and flat. Transport the composite mortar to the construction site and use a wet shotcreting machine for spraying operations. The working air pressure of the shotcreting machine should be controlled between 0.4 - 0.6 MPa, the spraying distance should be maintained at 0.8 - 1.2 m, and the spraying angle should be as perpendicular to the spraying surface as possible. According to the geological conditions and support requirements of the roadway, the formula of the composite mortar can be slightly adjusted. For example, in areas with broken surrounding rock and large ground pressure, appropriately increase the dosage of the accelerating agent to improve the early strength of the mortar; in parts with higher strength requirements, the proportion of cement can be appropriately increased. After shotcreting, carry out curing according to the curing standards. At normal temperature, the curing time should not be less than 7 days; in a humid environment, the curing time can be appropriately shortened, but not less than 5 days. During the curing period, regularly spray water to keep the shotcrete layer moist to ensure the normal growth of the mortar strength.

[0032] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. An inorganic quick-setting spray composite mortar for mining, including a mortar formula and a production process of the composite mortar, characterized in that: The formula of the mortar includes 60% river sand, of which coarse sand, with a specification of FM=3.7-3.1, medium sand with FM=3.0-2.3, fine sand with FM=2.2-1.6, and extra fine sand with FM=1.5-0.7, is mixed and each accounts for 15%; Portland cement P425 accounts for 21%; fly ash accounts for 6%; quick-setting agent accounts for 5%; slow-setting, anti-cracking, and flexible agent composite materials account for 8%; The production process of the composite mortar is industrialized production in a factory, as follows: Raw material preparation: strictly select river sand, silicate cement P425, fly ash, quick-setting agent, and slow-setting, anti-cracking, and flexible agent composite materials that meet quality standards, and accurately measure according to the formula; Stirring and mixing: Add the measured raw materials into the stirring equipment, stir at a low speed of 200 revolutions per minute for 5 minutes to make the raw materials initially mixed evenly; then adjust to a high speed of 500 revolutions per minute and stir for 15 minutes to ensure that the raw materials are fully and evenly mixed; Quality inspection: The finished mortar materials are tested for quality indicators such as compressive strength, setting time, fluidity, and rebound rate. They can only leave the factory after passing the inspection.

2. The inorganic quick-setting sprayed composite mortar for mining according to claim 1, characterized in that: During the industrial production process of the factory, the quality of raw materials is controlled to ensure that their mud content, particle shape and grading indicators meet the standards; the strength, setting time and stability performance indicators of the silicate cement P425 must meet the requirements.

3. The inorganic quick-setting sprayed composite mortar for mining according to claim 1, characterized in that: The activity index, fineness and water demand ratio of the fly ash must comply with regulations; the quick-setting agent ensures its initial setting time, final setting time and strength gain rate; the retarding, crack-resistant and flexible agent composite materials ensure that their retarding, crack-resistant and enhanced flexibility effects meet the design requirements.

4. The inorganic quick-setting sprayed composite mortar for mining according to claim 1, characterized in that: When it is necessary to adjust the strength grade of mortar, the proportion of Portland cement P425 can be increased, and the cement proportion can be increased by 1% to 3%, while the proportion of river sand can be reduced accordingly, with a reduction of 0.5% to 2%; when it is necessary to shorten the solidification period, the amount of accelerator can be increased by 0.2% to 0.5% for every 1 to 2 minutes shortening of the solidification time, and the amount of retarding component in the retarding, anti-cracking and flexible agent composite materials can be adjusted accordingly.

5. The inorganic quick-setting sprayed composite mortar for mining according to claim 1, characterized in that: After the fly ash replaces gravel, the bonding and hardening effects of the slurry are improved in the following ways: the active silicon oxide and active aluminum oxide in the fly ash undergo a secondary hydration reaction under the stimulation of calcium hydroxide produced by cement hydration, generating a large amount of hydrated calcium silicate and hydrated calcium aluminate gel, which fill the pores in the mortar, making the microstructure of the mortar denser, thereby improving the bonding strength of the slurry; at the same time, the spherical particle shape of the fly ash can improve the fluidity of the mortar in the mortar, help to evenly distribute the various components, and further enhance the hardening effect.

6. The inorganic quick-setting sprayed composite mortar for mining according to claim 1, characterized in that: In dry environments and construction scenarios with high requirements for initial strength, the mass ratio of accelerator to retarder is controlled between 3:1-5:1 to ensure that the mortar can quickly solidify and reach a certain strength; in humid environments or construction scenarios with longer requirements for setting time, the mass ratio of accelerator to retarder can be adjusted to between 1:1-2:1.

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