A method for preparing high-density foamed concrete suitable for filling the periphery of pipelines in long-distance tunnels, and the high-density foamed concrete prepared by the method.

Abstract

This invention belongs to the field of building materials, specifically relating to a method for preparing high-density foamed concrete suitable for filling the periphery of pipelines in long-distance tunnels. It aims to solve the problem of how to utilize metallurgical solid waste and slag solid waste to prepare high-density, low-strength foamed concrete suitable for special engineering applications. The invention includes the following steps: weighing 150-200 parts of active cementitious component, 300-500 parts of bulking component, 20-50 parts of metal fiber component, 7-15 parts of foaming agent, and 340-580 parts of water according to the specified mass ratio; mixing; foaming; and molding. The high-density foamed concrete preparation method for filling pipelines in long-distance tunnels provided by this invention features high bulk density and low strength, and also comprehensively utilizes various metallurgical and mining solid wastes.

Description

Technical Field

[0001] This invention belongs to the field of building materials, specifically relating to a method for preparing high-density foamed concrete suitable for filling the periphery of pipelines in long-distance tunnels, and the high-density foamed concrete prepared by this method. Background Technology

[0002] Oil and gas pipelines, as important energy infrastructure, play an irreplaceable role in ensuring energy security.

[0003] Oil and gas pipelines are typical long-distance linear structures, characterized by long construction distances, high geological variability, and difficulties in operation and maintenance. Especially after pipeline installation, ensuring the operational safety of long-distance pipelines is one of the major challenges facing the industry.

[0004] Currently, after the pipelines inside the tunnel are laid, the outer perimeter is mainly protected by water and sand filling. However, traditional water and sand filling has problems such as low strength and long construction period. Moreover, during the later operation, the water and sand filling needs to be cleaned during maintenance and needs to be filled with water and sand again after maintenance. Therefore, the maintenance and construction process is complicated and the cycle is long. In addition, the large amount of water and sand transported out will cause pollution to the surrounding environment.

[0005] Foamed concrete is widely used in underground space backfilling, soft soil subgrade filling, and building insulation materials due to its lightweight, good thermal insulation, excellent fluidity and certain strength.

[0006] Traditional foamed concrete is characterized by being lightweight and high-strength, meaning that the material density is as low as possible while the strength performance is as high as possible.

[0007] However, in certain special engineering applications, such as after long-distance pipelines are laid inside tunnels crossing rivers and seas, they need to be filled around their perimeter to stabilize the pipeline. This requires consideration of the structure's anti-buoyancy performance, necessitating a high density requirement for the filling material. Furthermore, considering the need for future pipeline maintenance, the strength of the filling material must be as low as possible to facilitate removal during maintenance. Therefore, the high-density, low-strength performance indicators sought in this special engineering application context are completely opposite to the lightweight, high-strength properties of traditional foamed concrete.

[0008] With the development of mining and metallurgical industries, a large amount of metallurgical solid waste and slag solid waste are generated. How to treat, recycle, and reuse these waste metallurgical solid waste and slag solid waste is the direction of development of the concept of sustainable development and environmental protection.

[0009] Therefore, how to effectively utilize metallurgical solid waste and slag solid waste to prepare high-density, low-strength foamed concrete suitable for such special engineering backgrounds has significant social and economic value. Summary of the Invention

[0010] To address the aforementioned problems in the prior art, namely how to utilize metallurgical solid waste and slag solid waste to prepare high-density, low-strength foamed concrete suitable for special engineering applications, this invention provides a method for preparing high-density foamed concrete suitable for filling the periphery of pipelines in long-distance tunnels, and the high-density foamed concrete prepared using this method.

[0011] The technical solution of the present invention includes:

[0012] A method for preparing high-density foamed concrete suitable for filling the periphery of pipelines in long-distance tunnels, characterized by comprising the following steps:

[0013] (1) Weighing: Weigh 150-200 parts of active gelling component, 300-500 parts of compounding component, 20-50 parts of metal fiber component, 7-15 parts of foaming agent and 340-580 parts of water according to the mass ratio for later use.

[0014] (2) Stirring: Mix the active gel component and the compounding component weighed in step (1) evenly, then add the weighed water and continue stirring to form a slurry. Then, while stirring, gradually add the weighed metal fiber component until all of it is added.

[0015] (3) Foaming: The foaming agent weighed in step (1) is diluted with water according to the dilution ratio to form a foaming agent aqueous solution. Then, compressed air is introduced into the foaming agent aqueous solution to generate foam.

[0016] (4) Molding: The slurry obtained in step (2) and the foam prepared in step (3) are mixed evenly by physical stirring to obtain high-density foamed concrete in a flowing state.

[0017] As an optional technical solution, the following testing steps are also included: pouring the high-density foamed concrete in the flow state obtained in step (4) into a standard cubic mold with a side length of 100mm, curing and solidifying it to obtain a molded foamed concrete test block, and then conducting material performance tests.

[0018] As an optional technical solution, the active cementitious component in step (1) is one or more of silicate cement, S95 grade mineral powder, grade 1 fly ash, silica fume, and metakaolin.

[0019] As an optional technical solution, the compounding component in step (1) consists of metallurgical solid waste powder and mining solid waste fine aggregate, wherein the particle size of the metallurgical solid waste powder is less than 0.5 mm and the particle size of the mining solid waste fine aggregate is 1.0 to 5.0 mm.

[0020] As an optional technical solution, the mass ratio of the metallurgical solid waste powder to the mining solid waste fine aggregate is 1:1.3 to 1:1.7.

[0021] As an optional technical solution, the metallurgical solid waste powder includes steel slag and waste lead powder.

[0022] As an optional technical solution, the fine aggregates of the mine solid waste include iron ore slag and copper ore slag.

[0023] As an optional technical solution, the metal fiber in step (1) is one or more of copper fiber, aluminum fiber, short tungsten fiber, carbon steel fiber, and stainless steel fiber.

[0024] As an alternative technical solution, the metal fiber density is greater than 8 g / cm³. 3 .

[0025] As an optional technical solution, the foaming agent in step (1) is a mixture of sodium fatty alcohol polyoxyethylene ether sulfate, triethanolamine, sodium dodecyl sulfate, diethanol monoisopropanolamine and lauramide propyl betaine, and the dilution ratio of the foaming agent is 25 to 50 times.

[0026] As an optional technical solution, the stirring time of the slurry in step (2) shall not be less than 3 minutes.

[0027] A high-density foamed concrete, characterized in that: the high-density foamed concrete is prepared by the preparation method described above.

[0028] The beneficial effects of this invention are:

[0029] (1) This invention uses metallurgical solid waste powder and mining solid waste fine aggregate as the weighting components, increases the weighting ratio and reduces the active cementitious component ratio, thereby increasing the bulk density of foamed concrete and avoiding excessive strength of foamed concrete caused by excessive use of active cementitious components in high-density foamed concrete, which is beneficial for excavation and demolition during pipeline maintenance.

[0030] (2) This invention uses metallurgical solid waste powders such as steel slag and waste lead powder, as well as fine aggregates of mining solid waste such as iron ore slag and copper ore slag as the weighting components to replace cement, thereby realizing the recycling of solid waste resources. This not only reduces the cost of foamed concrete materials, but also reduces the amount of cement used and the carbon emissions of foamed concrete. It has both high economic value and high environmental value.

[0031] (3) The method for preparing high-density foamed concrete suitable for filling long-distance tunnel pipelines provided by the present invention can increase the crack resistance and toughness of low-strength foamed concrete by adding metal fibers such as tungsten fibers; at the same time, the density of foamed concrete can be further increased by utilizing the high specific gravity of metal fibers. Detailed Implementation

[0032] The present application will now be described in further detail with reference to the embodiments. It is to be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the embodiments.

[0034] This invention provides a method for preparing high-density foamed concrete suitable for filling long-distance tunnels and pipelines, and the high-density foamed concrete prepared by this method.

[0035] The method for preparing high-density foamed concrete of the present invention includes the following steps:

[0036] (1) Weighing: Weigh 150-200 parts of active gelling component, 300-500 parts of compounding component, 20-50 parts of metal fiber component, 7-15 parts of foaming agent and 340-580 parts of water according to the mass ratio for later use.

[0037] (2) Stirring: Mix the active gel component and the compounding component weighed in step (1) evenly, then add the weighed water and continue stirring to form a slurry. Then, while stirring, gradually add the weighed metal fiber component until all of it is added.

[0038] (3) Foaming: The foaming agent weighed in step (1) is diluted with water according to the dilution ratio to form a foaming agent aqueous solution. Then, compressed air is introduced into the foaming agent aqueous solution to generate foam.

[0039] (4) Molding: The slurry obtained in step (2) and the foam prepared in step (3) are mixed evenly by physical stirring to obtain high-density foam concrete in a flowing state;

[0040] In step (1), the active cementitious component is one or more of the following: silicate cement, S95 grade mineral powder, grade 1 fly ash, silica fume, and metakaolin.

[0041] In step (1), the compounding components consist of metallurgical solid waste powder and mining solid waste fine aggregate, wherein the particle size of the metallurgical solid waste powder is less than 0.5 mm and the particle size of the mining solid waste fine aggregate is 1.0 to 5.0 mm.

[0042] The mass ratio of metallurgical solid waste powder to mining solid waste fine aggregate is 1:1.3 to 1:1.7.

[0043] Metallurgical solid waste powders include steel slag and waste lead powder.

[0044] Fine aggregates from mining solid waste include iron ore slag and copper ore slag.

[0045] In step (1), the metal fiber is one or more of copper fiber, aluminum fiber, short tungsten fiber, carbon steel fiber, and stainless steel fiber.

[0046] Metal fiber density greater than 8 g / cm³ 3 .

[0047] In step (1), the foaming agent is a mixture of sodium fatty alcohol polyoxyethylene ether sulfate, triethanolamine, sodium dodecyl sulfate, diethanol monoisopropanolamine and lauramide propyl betaine, and the foaming agent is diluted by 25 to 50 times.

[0048] The mixing time of the slurry in step (2) shall not be less than 3 minutes.

[0049] Table 1 shows the component ratios of Examples 1, 2, 3, and 4 according to the preparation method of the present invention with different component ratios, as well as the component ratios of Comparative Examples 1 and 2 according to the conventional foamed concrete preparation method:

[0050] Table 1

[0051] The raw materials for each embodiment and comparative example were weighed according to the mass proportions in the table above, and foamed concrete test blocks were obtained according to the preparation method described above. The test block samples corresponding to each embodiment and comparative example were tested for 28-day unconfined compressive strength, dry density, and drying shrinkage rate according to "Foamed Concrete" (JC / T 266-2011). The test results are shown in Table 2.

[0052] Table 2

[0053] As can be seen from the data in Tables 1 and 2, high-density foamed concrete with a dry density of A11 grade or higher can be prepared using the technical solution of the present invention.

[0054] As can be seen from Examples 1-4 and Comparative Example 1, using metallurgical solid waste and mining solid waste to replace the active cementitious components in foamed concrete can effectively increase the dry density of foamed concrete while reducing its compressive strength. When this foamed concrete is used for filling underwater oil and gas pipelines, it can provide good anti-buoyancy performance and facilitate pipeline maintenance during operation.

[0055] As can be seen from Comparative Examples 1 and 2, the addition of some metal fibers can further increase the dry density of foamed concrete, while its drying shrinkage rate is lower, and it has good crack resistance and toughness.

[0056] However, as shown in Comparative Example 3, if the proportions of the components are unbalanced, it will cause the properties of the prepared material to become extreme, which is not conducive to practical application.

[0057] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0058] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0059] The preferred embodiments of the present invention have been described above. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions resulting from these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing high-density foamed concrete suitable for filling the periphery of pipelines in long-distance tunnels, characterized in that, Includes the following steps: (1) Weighing: Weigh 150-200 parts of active gelling component, 300-500 parts of compounding component, 20-50 parts of metal fiber component, 7-15 parts of foaming agent and 340-580 parts of water according to the mass ratio for later use. (2) Stirring: Mix the active gel component and the compounding component weighed in step (1) evenly, then add the weighed water and continue stirring to form a slurry. Then, while stirring, gradually add the weighed metal fiber component until all of it is added. (3) Foaming: The foaming agent weighed in step (1) is diluted with water according to the dilution ratio to form a foaming agent aqueous solution. Then, compressed air is introduced into the foaming agent aqueous solution to generate foam. (4) Molding: The slurry obtained in step (2) and the foam prepared in step (3) are mixed evenly by physical stirring to obtain high-density foamed concrete in a flowing state.

2. The method for preparing high-density foamed concrete as described in claim 1, characterized in that: The active cementitious component mentioned in step (1) is one or more of silicate cement, S95 grade mineral powder, grade 1 fly ash, silica fume, and metakaolin.

3. The method for preparing high-density foamed concrete as described in claim 1, characterized in that: The compounding components mentioned in step (1) consist of metallurgical solid waste powder and / or mining solid waste fine aggregate, wherein the particle size of the metallurgical solid waste powder is less than 0.5 mm and the particle size of the mining solid waste fine aggregate is 1.0 to 5.0 mm.

4. The method for preparing high-density foamed concrete as described in claim 3, characterized in that: The mass ratio of the metallurgical solid waste powder to the mining solid waste fine aggregate is 1:1.3 to 1:1.

7.

5. The method for preparing high-density foamed concrete as described in claim 3, characterized in that: The metallurgical solid waste powder includes steel slag and waste lead powder, and the mining solid waste fine aggregate includes iron ore slag and copper ore slag.

6. The method for preparing high-density foamed concrete as described in claim 1, characterized in that: The metal fiber mentioned in step (1) is one or more of copper fiber, aluminum fiber, short tungsten fiber, carbon steel fiber, and stainless steel fiber.

7. The method for preparing high-density foamed concrete as described in claim 6, characterized in that: The density of the metal fiber is greater than 8 g / cm³. 3 .

8. The method for preparing high-density foamed concrete as described in claim 1, characterized in that: The foaming agent mentioned in step (1) is a mixture of sodium fatty alcohol polyoxyethylene ether sulfate, triethanolamine, sodium dodecyl sulfate, diethanol monoisopropanolamine and lauramide propyl betaine, and the foaming agent is diluted by 25 to 50 times.

9. The method for preparing high-density foamed concrete as described in claim 1, characterized in that: The stirring time of the slurry in step (2) shall not be less than 3 minutes.

10. A high-density foamed concrete, characterized in that: The high-density foamed concrete is prepared using the preparation method described in claim 1.

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