Preparation method and application of self-leveling filling waste pipeline material

Abstract

The invention belongs to the technical field of building materials, and particularly discloses a preparation method and application of a self-leveling filling waste pipeline material, and the preparation method comprises the following steps: obtaining water purification residual mud generated by treating sewage by pure equipment, mixing a debonding agent solution into the water purification residual mud in a stirring pot, and stirring by using a mortar planetary stirrer to obtain water purification residual mud slurry; the method comprises the following steps: preparing composite powder from cement powder and slag powder, doping the composite powder into the purified water residual mud slurry, and uniformly mixing for a first preset time by using a planetary mixer to form a flowing solidified residual mud slurry in a flowing state; storing the flowing cured residual mud slurry into a cylinder mold, vibrating, inserting and tamping on a cement mortar vibrating table for a second preset time, and demolding to obtain a cured residual mud filling material; the method has the following advantages: through resource utilization of the slag powder and cement solidification cooperation, the flowing effect before solidification is improved. The water purification residual mud is used as a main filling material, so that the production cost is low, the yield is high, the pollution is small and the flowing curing effect is good.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a preparation method and application of a self-leveling material for filling abandoned pipes. Background Art

[0002] As the urbanization process continues to advance, people's living standards continue to improve, and the supporting requirements for public infrastructure are increasing accordingly. The application scale of various purification equipment for sewage treatment (such as membrane separation devices, high-efficiency filtration units, etc.) in cities continues to expand, and the discharge of the auxiliary solid waste generated by them - water purification sludge is also increasing year by year. Some purification equipment operators in a certain city revealed that the amount of water purification sludge they transport out for disposal every day has reached hundreds of tons, and the output is quite considerable.

[0003] However, these water purification sludges face many difficulties in treatment and subsequent disposal: they usually have poor engineering properties such as high water content, high compressibility, rich agglomerates and high viscosity, which makes drying or dehydration difficult, transportation inconvenient, and storage and landfill processes difficult to manage. At the same time, since water purification sludge comes from the water filtration and purification process, various impurities and flocculants together form a relatively complex muddy or colloidal substance, which is difficult to achieve effective reduction and resource utilization under conventional treatment methods. Existing treatment methods are often based on temporary filling, stacking or landfilling, which not only occupies valuable land and space resources, but also poses certain environmental risks.

[0004] Therefore, how to effectively reduce, stabilize and recycle the clean water sludge produced by these sewage treatment purification equipment under the premise of taking into account both economy and environmental protection has become an important issue that needs to be urgently solved in the process of sustainable urban development.

[0005] Therefore, a preparation method and application of a self-leveling material for filling abandoned pipes are proposed to solve the above-mentioned problems. Summary of the invention

[0006] The present invention aims to provide a preparation method and application of a self-leveling material for filling abandoned pipes, so as to solve or improve the above-mentioned technical problems that the high water content and high viscosity of the purified water sludge make it difficult to handle, and the existing treatment methods occupy resources and space.

[0007] In view of this, a first aspect of the present invention is to provide a method for preparing a self-leveling material for filling abandoned pipes.

[0008] A second aspect of the present invention is to provide a self-leveling material for filling abandoned pipes.

[0009] The third aspect of the present invention is to provide an application of a self-leveling material for filling abandoned pipes.

[0010] The first aspect of the present invention provides a preparation method for a self-leveling filling material for waste pipelines, comprising the following steps: obtaining the purified water sludge generated by the purification equipment in sewage treatment, and respectively configuring the total mass of the composite powder and the total mass of the de-adhesive solution based on the total mass of the purified water sludge; mixing the de-adhesive solution into the purified water sludge in a stirring pot, and using a mortar planetary mixer to stir to obtain a purified water sludge slurry; preparing the composite powder by cement powder and slag powder, incorporating the composite powder into the purified water sludge slurry and using a planetary mixer to perform mixing for a first preset time to form a flowing and solidified residual sludge slurry; storing the flowing and solidified residual sludge slurry in a columnar mold, vibrating and ramming on a cement mortar vibrating table for a second preset time, and demolding to obtain a solidified residual sludge filling material.

[0011] The second aspect of the present invention provides a self-leveling filling material for waste pipelines, the raw materials of which include a composite powder, a de-adhesive solution and purified water sludge; the purified water sludge is in the state of a highly viscous slurry, and the components of the purified water sludge include at least one of silicon dioxide, aluminum oxide, iron oxide, potassium oxide, titanium dioxide, phosphorus pentoxide, magnesium oxide, calcium oxide; the mass ratio of the composite powder to the purified water sludge is in the range of 0.20 - 0.30; the mass ratio of the de-adhesive solution to the purified water sludge is in the range of 0.17 - 0.19.

[0012] The third aspect of the present invention provides an application of a self-leveling filling material for waste pipelines, comprising the following steps: placing a stirring bucket on the ground, and excavating earthwork above the underground waste pipeline to be treated to form a through grouting hole; connecting the stirring bucket and the grouting pump to the grouting hole of the underground waste pipeline through a slurry delivery pipe; in the stirring bucket, mixing the composite powder, the de-adhesive solution and the purified water sludge to obtain the flowing and solidified residual sludge slurry; pumping the flowing and solidified residual sludge slurry into the underground waste pipeline through the grouting pump and the slurry delivery pipe, and repeatedly pumping until the slurry filling in the waste pipeline is completed.

[0013] The beneficial effects of the present invention compared with the prior art:

[0014] The process of the present invention is simple, convenient, has low energy consumption, wide applicability, and has good green environmental protection benefits and social safety benefits.

[0015] The present invention conducts resource utilization on the solid waste of slag powder, and proposes a solution to solve the problems of its large quantity and high treatment cost. The raw materials used include cement products with a high degree of industrial maturity, supplemented by slag powder for co-solidification, which improves the solidification effect and is conducive to the development of the waste resource economy.

[0016] The present invention uses readily available sodium citrate as a debonding agent, effectively solving the problem of high viscosity of the purified water sludge, enabling the purified water sludge to have high fluidity without complex treatment.

[0017] The present invention uses the purified water sludge, an accessory product in water plant production, as the main agent of the self-leveling filling material. Compared with the commonly used foam concrete filling materials at present, it has the advantages of low production cost, large output, low pollution, etc., and does not require the addition of extra additives, and has good flow and solidification effects.

[0018] The additional aspects and advantages of the embodiments according to the present invention will become apparent in the following description section, or be learned through the practice of the embodiments according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, wherein:

[0020] Figure 1 is a flowchart of the method steps of the preparation method of the present invention;

[0021] Figure 2 is a flowchart of the method steps of the application method of the present invention;

[0022] Figure 3 is a schematic diagram of the grouting construction application of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

[0024] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention may be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0025] Please refer to Figures 1 - 3 , and the preparation method and application of a self-leveling filling waste pipeline material according to some embodiments of the present invention will be described below.

[0026] An embodiment of the first aspect of the present invention provides a material for self-leveling filling of waste pipelines. In some embodiments of the present invention, the raw materials of the material for self-leveling filling of waste pipelines include composite powder, debonding agent solution and purified water sludge; the purified water sludge is in the state of a highly viscous slurry, and the components of the purified water sludge include at least one of silicon dioxide, aluminum oxide, iron oxide, potassium oxide, titanium dioxide, phosphorus pentoxide, magnesium oxide, and calcium oxide.

[0027] The mass ratio of the composite powder to the purified water sludge is in the range of 0.20 to 0.30.

[0028] The mass ratio of the deflocculant solution to the purified water sludge is in the range of 0.17 to 0.19.

[0029] A self-leveling filling material for waste pipelines provided by the present invention, the composite powder is a key component added to improve the solidification ability of the purified water sludge. The purified water sludge itself has a high water content and high viscosity, which is difficult to operate directly and may affect its filling effect. The composite curing agents interact with each other to make the slurry form a more solid structure, and make the slurry form a more solid structure. Its curing process helps to improve the stability of the material in the pipeline, preventing premature loss of fluidity or excessive swelling. For example, gypsum, calcium chloride, calcium aluminate, etc. are used as components of the composite powder. The mass ratio of the composite powder is 0.20 to 0.30 of the purified water sludge, which can ensure that the curing reaction does not occur too quickly, leaving enough time to complete the filling process, and at the same time avoid cracks and cracking problems caused by excessive drying.

[0030] The deflocculant solution is an important component used to reduce the high viscosity of the purified water sludge. Since the purified water sludge will form aggregates with high viscosity during the water treatment process, directly using it for filling may cause excessive viscosity, affecting the fluidity and self-leveling effect of the material. The deflocculant solution can reduce this viscosity and enhance the fluidity of the slurry, ensuring that the material can be evenly distributed in the waste pipeline in a self-leveling manner. The addition of this solution can effectively reduce blockage problems and ensure the construction convenience during the filling process. The deflocculant solution can be selected to be made of certain surfactants, dilute acids or certain water-soluble polymers. The mass ratio of the deflocculant solution is set between 0.17 and 0.19 of the purified water sludge, ensuring that the deflocculant can fully play its role, avoiding excessive or insufficient use, and ensuring that the fluidity and operability of the material reach the best effect.

[0031] By reasonably controlling the mass ratio of the composite curing agent to the purified water sludge, the curing process of the filling material in the pipeline can be made more stable. Too high a proportion of the composite curing agent may cause the material to cure too quickly, thus affecting the filling effect; while too low a proportion may cause the material to not be effectively cured, affecting the performance of the flowing and solidifying sludge. Therefore, setting the ratio between 0.20 and 0.30 can optimize the curing speed and performance while ensuring the filling effect. The ratio of the deflocculant solution to the purified water sludge is set between 0.17 and 0.19, ensuring that the viscosity in the purified water sludge is reduced without affecting its filling characteristics itself. The use of the deflocculant solution enables the highly viscous slurry to flow more smoothly into the waste pipeline and form a uniform filling layer in the pipeline. By reasonably regulating the ratio of the deflocculant, it is possible to avoid the slurry being too thin and affecting the filling effect.

[0032] In any of the above embodiments, the composite powder includes cement powder and slag powder, and the mass ratio of slag powder to cement powder is in the range of 0.1 to 1.

[0033] In this embodiment, the cement powder is one of the main components of the composite powder and has a very strong solidification ability. The basic components of cement include calcium oxide (CaO), which reacts with water to form calcium hydroxide (Ca(OH) 2 ), and further reacts with other components to form mineral compounds such as calcium silicate and calcium aluminate. These compounds provide a strong structural foundation during the hardening process of cement. Therefore, the addition of cement powder can improve the solidification efficiency of the composite solidifying agent, ensuring that the filling material can firmly bond after being filled in the pipeline and form a filling layer with high mechanical strength. Commonly used types of cement powder include ordinary Portland cement, slag cement, or other special cements. When the mass ratio of cement powder is relatively high, it helps to accelerate the hydration reaction of cement and achieve high-strength solidification in a short time, which is suitable for scenarios that require rapid filling and sealing.

[0034] Slag powder is an industrial by-product, and its components mainly include silicon dioxide (SiO 2 ), calcium oxide (CaO), and aluminum oxide (Al 2 O 3 ) and other minerals. The addition of slag powder can improve the hydration process of cement powder, making the cement reaction slower and more stable, and reducing the adverse effects caused by rapid solidification. When slag powder and cement powder act together, compounds such as calcium silicate and calcium aluminate will be generated, which help to enhance the durability, impermeability, and chemical corrosion resistance of the material during the later hardening process. Therefore, slag powder not only improves the overall performance of the material but also enhances its environmental friendliness, making it more in line with the requirements of sustainable development. Common slag powders include blast furnace slag powder. As a waste resource, the addition of slag powder can effectively utilize industrial waste, reduce the overall cost of the material, and improve its durability. In practical applications, the proportion of slag powder can be adjusted according to different solidification requirements and environmental conditions.

[0035] It should be clear that the composite solidifying agents can interact with each other, utilize the synergy of the alkalinity of cement and the activity of slag powder to solidify the purified water sludge. And due to the addition of slag micro-powder, the slag powder is inserted between the cement and the purified water sludge particles, reducing its hydration rate and prolonging the time for the purified water sludge to maintain fluidity after adding the composite solidifying agent.

[0036] In any of the above embodiments, the components of the slag powder include at least one of calcium oxide, silicon dioxide, sulfur trioxide, aluminum oxide, iron oxide, magnesium oxide, sodium oxide, and potassium oxide.

[0037] In this embodiment, the filling requirements for the abandoned pipeline need to balance rapid curing and long-term stability. In this case, the following proportion of slag powder components can be selected: calcium oxide (CaO) accounts for 30%, silicon dioxide (SiO 2 ) accounts for 25%, sulfur trioxide (SO 3 ) accounts for 5%, aluminum oxide (Al 2 O 3 ) accounts for 15%, iron oxide (Fe 2 O 3 ) accounts for 10%, magnesium oxide (MgO) accounts for 5%, sodium oxide (Na 2 O) and potassium oxide (K 2 O) together account for 10%. This ratio can ensure that the filling material has good fluidity and a suitable curing speed in the initial stage, and at the same time shows stronger durability and impermeability in the later stage, avoiding the adverse effects caused by excessive amounts of certain components in the slag powder.

[0038] In any of the above embodiments, the components of the cement powder include at least one of calcium oxide, silicon dioxide, aluminum oxide, iron oxide, magnesium oxide, sulfur trioxide, potassium oxide, and titanium dioxide.

[0039] In this embodiment, taking the material for filling the abandoned pipeline as an example, according to requirements, the proportion of the components of the cement powder can be optimized in the following way: calcium oxide (CaO): 40% - 50%, silicon dioxide (SiO 2 ) : 25% - 30%, aluminum oxide (Al 2 O 3 ) : 10% - 15%, iron oxide (Fe 2 O 3 ) : 5% - 10%, magnesium oxide (MgO): 2% - 5%, sulfur trioxide (SO 3 ) : 2% - 4%, potassium oxide (K 2 O): 0% - 2%, titanium dioxide (TiO 2 ) : appropriate amount (depending on requirements). If high strength and impermeability are required for filling the pipeline, appropriately increase the proportion of silicon dioxide and aluminum oxide, such as the silicon dioxide content is 30% and the aluminum oxide is 15%, while reducing the proportion of potassium oxide to less than 1%. This can not only ensure that the filling material has higher long-term durability but also prevent swelling problems. For scenarios that require rapid repair and filling, the proportion of calcium oxide can be increased to about 50%, while reducing the content of silicon dioxide and aluminum oxide, so that the reaction speed of the cement is accelerated to meet the requirements of rapid curing.

[0040] In any of the above embodiments, the debonding agent solution includes a sodium citrate solution; the sodium citrate in the sodium citrate solution accounts for 6 - 12 parts by mass, and the water in the sodium citrate solution accounts for 88 - 94 parts by mass.

[0041] In this embodiment, by heating the sodium citrate solution to a certain temperature (e.g., 50 °C) and performing pre-treatment before use, it becomes more soluble and can better penetrate into the highly viscous area of the purified water sludge, thereby reducing the amount of deflocculant required and achieving good results.

[0042] An embodiment of the second aspect of the present invention provides a preparation method for producing the self-leveling filling waste pipe material in any of the above embodiments. In some embodiments of the present invention, as Figure 1 shown, the preparation method includes the following steps:

[0043] S101, based on the total mass of the composite powder, take 0 - 33.3 parts by weight of slag powder and 33.3 - 66.7 parts by weight of cement, and preliminarily mix them under normal temperature and dry conditions to obtain a composite curing agent powder body.

[0044] S102, based on the total mass of the deflocculant solution, take 6 - 12 parts by weight of sodium citrate and 88 - 94 parts by weight of water, dissolve the sodium citrate in water to make a deflocculant solution, and mix it into the purified water sludge in a mixing pot, and use a planetary mortar mixer to stir to obtain a purified water sludge slurry body.

[0045] S103, configure the composite powder through cement powder and slag powder, incorporate the composite powder into the purified water sludge slurry body and use a planetary mixer to perform mixing for a first preset time to form a flowing cured sludge slurry body in a flowing state.

[0046] S104, deposit the flowing cured sludge slurry body into a columnar mold, vibrate and tamp it on a cement mortar vibrating table for a second preset time, and then demold to obtain a cured sludge filling material.

[0047] A preparation method proposed by the present invention. The purpose of step S101 is to prepare a composite curing agent powder body, which is an important part of the self-leveling filling waste pipe material. By mixing slag powder and cement powder, a powder material with good curing performance is obtained. In this step, the mass ratio of slag powder to cement powder is adjusted by controlling the addition amount of slag powder and the proportion of cement (0 - 33.3 parts by weight of slag powder, 33.3 - 66.7 parts by weight of cement) to control the properties of the curing agent, ensuring the strength, fluidity and self-leveling characteristics of the material. Suppose the mass of the selected slag powder is 20 parts by weight and the mass of the cement is 50 parts by weight (within the range of the two). Under normal temperature and dry conditions, these two powders are first roughly mixed, and then further carefully mixed using a stirrer to ensure their uniform distribution, providing stability and uniformity for the subsequent use of the composite curing agent powder body. By precisely controlling the ratio of slag powder to cement powder, characteristics such as the hardness, drying time and durability of the final curing agent can be adjusted. The introduction of slag powder can improve the compressive strength of cement and reduce costs, while the addition of cement can provide good adhesiveness and stability for the curing system. The optimization of this mixing ratio and process is the key to ensuring the smooth molding and good performance of the subsequent self-leveling filling material.

[0048] In step S102, the preparation of the de-adhesive solution is to solve the problem of the high viscosity of purified water sludge. By mixing sodium citrate with water to form a solution, the viscosity of the sludge can be effectively reduced, its fluidity can be improved, and the phenomenon of adhesion or blockage during the subsequent stirring process can be avoided. The addition of the de-adhesive solution makes it easier for the purified water sludge to be fully mixed with the composite powder during the stirring process. The mass of the selected sodium citrate is 8 parts by weight and the mass of the water is 92 parts by weight (meeting the ratio requirements of 6 - 12 parts by weight and 88 - 94 parts by weight). First, add sodium citrate to water and completely dissolve it under stirring to form a clear de-adhesive solution. This solution has strong solubility and can quickly penetrate the high-viscosity area of the purified water sludge, making it exhibit lower adhesion force, facilitating subsequent operations. Sodium citrate as a de-adhesive can effectively destroy the viscous structure in the purified water sludge, promote the fluidity of the sludge, and make the subsequent stirring process smoother. In addition, the water solubility of the solution also helps to reduce the negative impact of the de-adhesive on the material itself, ensuring the stability and uniformity of the material during the construction process. The reasonable ratio of sodium citrate to water ensures the persistence and effectiveness of the de-adhesive effect.

[0049] In step S103, the purpose of mixing the composite curing agent powder body with the water purification residual mud slurry is to fully combine the two to form a solidified residual mud slurry with strong fluidity. By using the planetary mixer for mixing again, the uniform distribution between the composite curing agent powder body and the water purification residual mud slurry is ensured, so that the final flowable solidified residual mud slurry has both sufficient fluidity and good stability and strength after solidification. During the mixing process, the prepared composite curing agent powder body (such as 20 parts by weight of slag powder, 50 parts by weight of cement powder) is added to the water purification residual mud slurry that has been stirred evenly. Use a planetary mixer to stir fully, and stir repeatedly for many times to ensure that the composite curing agent powder body and the mud body are completely fused. At this time, the slurry shows good fluidity and can effectively fill the gap of the abandoned pipeline. This mixing process not only ensures the uniform fusion of the curing agent and the slurry, but also through the efficient stirring function of the planetary mixer, it can ensure that the interaction between the curing agent powder and the water purification residual mud is optimal, avoiding the situation of inconsistent physical properties due to uneven mixing. This mixed flowing solidified residual mud slurry has good workability, can easily fill various gaps in the pipeline, and form a stable repair effect after solidification.

[0050] In step S104, after the fluidized solidified mud slurry is fully mixed, it is stored in a column mold for vibration and tamping treatment. The function of vibration and tamping is to remove bubbles in the material through mechanical vibration, making the material more compact and avoiding the appearance of voids or cracks after solidification. The fluidized solidified mud after demoulding will form a solid and stable solidified object, thereby achieving the solidification of the purified water mud. The evenly stirred fluidized solidified mud slurry is poured into the column mold, and the mold size is selected according to the actual needs of filling the pipe. The mold is vibrated and tamped using a cement mortar vibration table to ensure that the slurry is evenly distributed in the mold and to remove excess bubbles. After a period of vibration and tamping, demoulding is performed to obtain the fluidized solidified mud after solidification. The vibration and tamping treatment can not only enhance the density of the fluidized solidified mud, but also ensure that the final shape of the material meets the engineering requirements. By removing bubbles, voids or cracks can be avoided after solidification, thereby improving the compressive strength and durability of the material.

[0051] It should be made clear that the solidified residual mud after demoulding is an experimental material, such as a compressive strength test, to detect whether the current component ratio configuration meets the current performance requirements. The purpose of filling the pipeline can only be achieved when the composite curing agent powder and the purified water residual mud slurry are mixed and injected into the pipeline in a flowing state.

[0052] Specifically, the total mass of the composite curing agent powder and the total mass of the debonding agent solution are set based on the mass of the purified water sludge, respectively.

[0053] As described above, the total mass of the composite curing agent powder can be dynamically adjusted based on the mass of the purified water sludge, but it should be determined according to the moisture content and viscosity characteristics of the purified water sludge. For example, for purified water sludge with a relatively high water content, the proportion of the composite curing agent powder can be appropriately reduced to avoid the slurry becoming too hard due to excessive curing agent, resulting in the loss of good fluidity and self-leveling performance. On the other hand, for purified water sludge with high viscosity and high agglomeration, the dosage of the curing agent can be appropriately increased to ensure good curing effect.

[0054] Similarly, the total mass of the deflocculant solution should also be dynamically adjusted according to the viscosity of the purified water sludge. For purified water sludge with high viscosity and difficult to stir, the proportion of the deflocculant solution can be appropriately increased to reduce the viscosity of the slurry and ensure the smooth progress of the subsequent stirring process. At the same time, the proportion of sodium citrate in the deflocculant solution can also be finely adjusted according to the acid-base and viscosity characteristics of the purified water sludge to achieve the best deflocculation effect while avoiding excessive use of sodium citrate, resulting in too high cost.

[0055] Specifically, the composite powder is used to maintain the fluidity of the purified water sludge slurry after curing the purified water sludge.

[0056] As described above, the main components of the composite powder include cement powder and slag powder, but to enhance fluidity, a certain proportion of high-efficiency fluidizing agent can be added. The addition of the fluidizing agent helps to reduce the viscosity of the slurry during the curing process, maintain its good fluidity, and avoid premature solidification or caking. These fluidizing agents can be inorganic salts or organic polymers, which can form a synergistic effect with the cement powder and slag powder during the curing process, so that the slurry still maintains a certain fluidity after curing, ensuring the smooth progress of the subsequent construction operations.

[0057] In terms of the particle size of the composite powder, through micronization treatment, the particle sizes of the slag powder and cement powder can be refined to a certain range, especially optimized in terms of specific surface area to increase the contact area between them and the cement slurry and purified water sludge, thereby improving the reaction rate and fluidity during the curing process. In addition, considering the possible gelling phenomenon during the curing process, the surface of the composite powder particles can be specially treated, such as coating a thin waterproof or anti-adhesion coating to reduce the adhesion force between the cement and slag particles, further enhancing the fluidity of the slurry.

[0058] During the curing process, the addition amount of the composite powder should not only consider the characteristics of the purified water sludge, but also can be appropriately adjusted according to the real-time fluidity feedback of the slurry. For example, an intelligent control system can be designed to adjust the dosing amount of the composite powder in real time according to the viscosity change during the stirring process. When the slurry shows premature hardening or too high viscosity, the system automatically increases the dosing amount of the fluidizing agent; on the contrary, when the fluidity is too strong, the proportion of the fluidizing agent is appropriately reduced to maintain the stable fluidity of the slurry. This fluidity adjustment mechanism based on feedback control can achieve precise control during the production process, avoid unnecessary waste, and ensure the quality and construction efficiency of the final product.

[0059] In order to ensure that the purified water sludge slurry after curing can not only maintain sufficient fluidity but also form a stable structure after curing, a slow-release curing agent can be introduced in the use of the composite powder. These slow-release curing agents can slowly release reactive substances during the curing process, delaying the speed of the curing reaction, so that the slurry can maintain fluidity for a longer time and reduce the risk of its premature setting or blocking the mold. This method not only improves the flexibility of production but also ensures the integrity and quality of the finished product.

[0060] Furthermore, before the cement powder contacts the purified water sludge slurry, the slag powder is mixed with the cement powder to form an isolation layer between the particles of the cement powder, and the hydration reaction of the cement is inhibited through the isolation layer to maintain long-distance and long-time fluidity in the pipeline.

[0061] As can be seen from the above, before the cement powder contacts the purified water sludge slurry, the slag powder is first fully mixed with the cement powder so that the slag powder is evenly filled and distributed between the particles of the cement powder, forming a homogeneous and continuous isolation layer structure. Since the particle size of the slag powder is relatively fine and it has a strong physical filling effect, it can effectively increase the gap between the particles of the cement powder, reduce the contact probability between the particles, and significantly delay the contact and reaction between the cement powder and the free water in the purified water sludge. Thus, the isolation layer formed by the slag powder can effectively inhibit the early rapid hydration reaction of the cement powder, slow down the generation rate of the initial gel products (such as calcium hydroxide, C-S-H gel) in the system, and thereby maintain the fluidity of the mixed slurry for a longer time. This measure enables the curing material to maintain better pumpability and construction performance during pipeline transportation, realizes the long-distance transportation of the slurry, effectively prevents the blockage problem caused by premature setting of the mixed slurry during transportation, and greatly improves the flexibility and economy of the construction process. In addition, this physical isolation state between the slag powder and the cement powder particles can gradually weaken in the later stage of the system, enabling the slag powder to gradually participate in the secondary hydration reaction (Poisson reaction) coordinated with the cement powder, thereby further enhancing the strength, structural compactness, and impermeability and durability of the final curing material, and realizing the efficient resource utilization of the purified water sludge.

[0062] Furthermore, the composite powder is used to maintain the fluidity of the purified water sludge slurry after solidifying the purified water sludge; and the first preset time is set according to the mass ratio of the slag powder to the cement powder. The first preset time is used to adjust the stirring time to ensure that the time for the cement hydration reaction can be adjusted under the same mass ratio, so as to adapt to the internal flow length of pipes with different lengths and the flow time affected by bending, pipe diameter, and inner wall roughness, enabling the stirred mixture to solidify at the correct position after flowing.

[0063] As can be seen from the above, by formulating the composite powder with a reasonable ratio of slag powder to cement powder, the fluidity retention time of the purified water sludge slurry before solidification can be effectively controlled to meet the requirements of different construction environments; specifically, the mass ratio of slag powder to cement powder in the composite powder directly determines the rate of the cement hydration reaction in the mixed slurry, thereby affecting the duration of the slurry's fluidity retention. Therefore, during the actual engineering implementation, a reasonable first preset time can be determined and set in advance according to parameters such as the length of the on-site pipeline transportation, pipe diameter, bending degree, and inner wall roughness of the pipeline, so as to accurately adjust the on-site stirring time of the slurry.

[0064] For example, when the transportation distance is relatively long (such as 800 meters to 1000 meters), the inner wall of the pipeline is relatively rough, there are multiple elbows, and the pipe diameter is relatively small, the upper limit range of the mass ratio of slag powder to cement powder of about 0.8 can be selected, and the first preset time can be set to 30 minutes to ensure that the slurry remains in a flowing state for a long time during transportation, effectively preventing the slurry from blocking the pipeline or failing to reach the designated position due to premature solidification. On the contrary, for a construction environment with a relatively short pipeline length (such as 100 meters to 200 meters), a relatively large pipe diameter, fewer bends, and a relatively smooth inner wall of the pipeline, the lower limit range of the mass ratio of slag powder to cement powder of 0.3 can be selected, and the first preset time can be set to 15 minutes to ensure that the slurry can be quickly transported to the target position and solidify in time, avoiding a decrease in engineering efficiency caused by the long-term non-solidification of the slurry.

[0065] Furthermore, the de-adhesive solution is used to relieve the high viscosity of the purified water sludge slurry and improve the fluidity of the flow-cured residual sludge slurry; and the second preset time is set according to the currently filled length of the abandoned pipeline. Through the second preset time, it is possible to pre-judge whether the flow-cured residual sludge slurry can change between the flowing state and the solidified state at the current time, so as to judge whether the flow-cured residual sludge slurry under this condition is qualified.

[0066] As described above, the debonding agent solution is mainly used in the actual construction process to significantly reduce the high viscosity of the purified water sludge slurry, so as to improve the overall fluidity after the slurry is mixed with the composite powder, facilitating the smooth and stable long-distance transportation of the slurry in the abandoned pipeline and accurately achieving solidification. Specifically, after the debonding agent solution is added, it can quickly and effectively destroy the aggregate structure existing in the purified water sludge, fully disperse the particles in the slurry, rapidly reduce the viscosity, and significantly improve the overall fluidity performance.

[0067] Meanwhile, in order to accurately evaluate the flow and solidification performance of the slurry during the filling and transportation process in the pipeline, the second preset time can be set according to the current filling length of the abandoned pipeline, and then the real-time monitoring and judgment of the transition of the slurry flow state to the solidification state can be realized at the construction site. For example, when the filling length of the abandoned pipeline is relatively long (such as more than 500 meters of the pipeline has been filled), the second preset time can be set to 20 minutes, that is, the first state detection is carried out 20 minutes after the slurry enters the pipeline for transportation. At this time, if the slurry still has good fluidity, it indicates that the current slurry mixing ratio, the addition amount of the debonding agent, and the stirring process parameters are suitable for the long-distance transportation requirements; otherwise, the mixing process or the dosage of the debonding agent can be adjusted in time to avoid pipeline blockage caused by premature coagulation of the slurry. When the filling length of the abandoned pipeline is relatively short (such as the filling length is between 100 meters and 200 meters), the second preset time can be shortened to about 10 minutes to quickly judge whether the slurry has appropriate fluidity and appropriate setting time under the short-distance transportation conditions, preventing the slurry from not solidifying for a long time or solidifying too fast, and ensuring that the slurry always meets the expected construction requirements.

[0068] Specifically, the debonding agent solution is used to relieve the high viscosity of the purified water sludge slurry and improve the fluidity of the flow-cured residual slurry.

[0069] As described above, in addition to the sodium citrate solution, other types of low-cost and environmentally friendly debonding agents can be considered, such as natural high-molecular polymers (such as chitosan, etc.) or inorganic salts (such as calcium chloride, sodium sulfate). These new debonding agents can act synergistically with the sodium citrate solution to jointly exert the debonding effect and control the viscosity of the slurry, avoiding excessive cost or environmental burden caused by the excessive use of a single debonding agent. For example, natural high-molecular polymers form molecular chains in the solution, which can effectively reduce the internal friction of the slurry, making the slurry more uniform during the stirring process, reducing caking and agglomeration phenomena, and thus enhancing the fluidity.

[0070] The proportion of the debonding agent solution should not be completely fixed, but should be adjusted in real time according to the viscosity and moisture content of the purified water sludge. By adding an on-line detection system, the viscosity and fluidity of the slurry can be monitored in real time, and the dosage of the debonding agent can be automatically adjusted. When the viscosity of the slurry is high (such as when the moisture content in the purified water sludge is low), the proportion of the debonding agent solution can be increased to ensure good fluidity of the slurry; while when the viscosity is low (such as when the moisture content of the purified water sludge is high), the dosage of the debonding agent is reduced to avoid excessive fluidity of the slurry caused by excessive debonding agent, thus ensuring the stability of the post-curing effect.

[0071] To improve the efficiency and reduce the dosage of the debonding agent solution, a controlled release technology can be adopted, that is, by designing a slow-release formulation of the debonding agent solution, the debonding agent gradually releases its effect when contacting with the purified water sludge slurry. This can be achieved by combining the debonding agent with a carrier material (such as ultra-fine powder, natural polymer material or hydrogel) to control the release rate of the debonding agent, making the debonding process more uniform and continuous, so as to maintain the fluidity of the slurry for a longer time and avoid premature failure.

[0072] Introducing a cross-linking technology into the debonding agent solution enables the debonding agent solution to form a certain three-dimensional network structure after being added to the purified water sludge slurry. This cross-linked structure can better control the distribution of the debonding agent solution, avoid rapid dissolution or diffusion, and at the same time maintain the continuous debonding effect on high-viscosity substances. During the curing process, the cross-linked network structure can effectively disperse the solid particles in the slurry, enhance the fluidity, make the flowing and curing residual slurry more uniform and stable in subsequent operations, and improve the smoothness of the construction process.

[0073] Furthermore, in the self-leveling filling material of the present invention, based on the total mass of the wet soil of the purified water sludge, the mass percentage of slag powder is 0-10%, such as 0%, 5%, 10%, preferably 10%; the mass percentage of cement is 10%-20%, such as 10%, 15%, 20%, preferably 15%; the mass percentage of sodium citrate is 1%-2%, such as 1%, 1.5%, 1.75%, 2%, preferably 1.75%; the mass percentage of water is 16.7%.

[0074] In each of the following examples of the present invention, the slag powder used is S95 grade ground granulated blast furnace slag powder, and its chemical composition is shown in Table 1. The cement used is pozzolanic Portland PP32.5 cement powder, and its chemical composition is shown in Table 2. The purified water sludge used is the original wet soil produced by the water plant, and its basic physical properties and chemical composition are shown in Tables 3 and 4.

[0075] Table 1 Chemical composition of slag powder

[0076]

[0077] Table 2 Chemical composition of PP325 cement

[0078]

[0079] Table 3 Basic physical properties of water purification sludge

[0080]

[0081] Table 4 Chemical composition of water purification sludge

[0082]

[0083] In any of the above embodiments, the debonding agent ratio is designed. Based on the total mass of the debonding agent, the mass ratio of sodium citrate is 6%-12%, and the mass ratio of water is 88%-94%. A total of 4 groups of debonding agent ratios are designed, as shown in Table 5. Sodium citrate is dissolved in water according to the weight of the debonding agent ratio to obtain a deflocculating agent.

[0084] Table 5 Debonding agent ratio

[0085]

[0086] The debinder liquid prepared in each ratio in this embodiment was mixed with the purified water residual mud, and then placed in a planetary mixer and fully stirred for 4 minutes to obtain a purified water residual mud slurry.

[0087] In any of the above embodiments, the above debonding agent ratio is used to prepare the self-leveling filling material. Based on the wet soil mass of the original water-cleaning residual mud, the curing agent is mixed with the water-cleaning residual mud slurry at a mass dosage of 20%-25%, and a planetary mixer is used to stir for 10 minutes to obtain a flowing solidified residual mud self-leveling filling material. The flowability and unconfined compressive strength at 28 days of age are tested, and pure cement is used as a curing agent for curing for comparison. The test results are shown in Table 6.

[0088] Table 6 Fluidity and strength (sodium citrate)

[0089]

[0090]

[0091] From the test results in Table 6, it can be concluded that the solidifying agent prepared with "cement + slag powder" has good flow-solidifying effect on purified water sludge. Under the action of the deflocculant with a sodium citrate dosage of 1%, when the dosage of the solidifying agent is 25%, the unconfined compressive strength of the flow-solidified sludge solid at the age of 28 days is 26.67 kPa; when the dosage of sodium citrate increases, the strength decreases. For example, when the dosage of sodium citrate is 2% and the dosage of the solidifying agent is 25%, its strength at the age of 28 days is only 6.67 kPa, but its fluidity is greatly improved. Compared with the cement solidifying agent, the unconfined compressive strength of the flow-solidified sludge solid with "cement + slag powder" as the solidifying agent at the age of 28 days is less than that of the cement solid, but the important index "fluidity" of the flow-solidified sludge is better than that of the cement solid. Under the action of the deflocculant with a sodium citrate dosage of 1.75%, with the increase of the cement dosage, the flow value of the flow-solidified sludge is 23.1%, 11.2%, and 4.7% higher than that of the cement solid.

[0092] The solidifying agent prepared with "cement + slag powder" shows good flow-solidifying effect on purified water sludge under the action of the deflocculant, and can largely meet the fluidity and strength requirements of the urban underground abandoned pipeline filling project.

[0093] In any of the above embodiments, using sodium citrate as the main deflocculant can effectively reduce the system viscosity of the purified water sludge and greatly improve its fluidity. After optimization by adding ferrous sulfate salt with strong redox effect based on the test data in Table 6, a self-leveling filling material is prepared. Similarly, based on the wet soil quality of the original purified water sludge, the solidifying agent is mixed with the purified water sludge slurry at a mass dosage of 20% - 25%, and stirred for 10 minutes with a planetary mixer to obtain a self-leveling filling material for flow-solidified sludge. The initial fluidity and the unconfined compressive strength at the age of 28 days are tested, and cement is used as a comparison. The test results are shown in Table 7.

[0094] Table 7 Fluidity and Strength (Ferrous Sulfate)

[0095]

[0096]

[0097] An embodiment of the third aspect of the present invention proposes an application method implemented by using the material for self-leveling filling of abandoned pipelines in any of the above embodiments. In some embodiments of the present invention, as Figures 2 - 3 shown, the application method includes the following steps:

[0098] S201, place a mixing barrel on the ground, and excavate soil above the underground abandoned pipeline to be treated to form a through grouting hole.

[0099] S202. Connect the mixing barrel and the grouting pump to the grouting hole of the underground abandoned pipeline through the slurry pipeline.

[0100] S203. In the mixing barrel, stir and mix the composite powder, the deflocculant solution and the purified water sludge to obtain a flowing and solidifying sludge slurry.

[0101] S204. Pump the flowing and solidifying sludge slurry into the underground abandoned pipeline through the grouting pump and the slurry pipeline, and repeatedly pump it until the slurry filling in the abandoned pipeline is completed.

[0102] An application method proposed by the present invention involves excavating earthwork above the location of the underground abandoned pipeline to be treated to form a through grouting hole. The key to this operation is to ensure smooth docking between the grouting hole and the abandoned pipeline so that the grout can be smoothly injected into the pipeline through the grouting hole. Generally, the grouting hole needs to be of sufficient size to ensure uniform distribution of the grout inside the pipeline and achieve the required filling effect. In addition, when excavating the earthwork, attention should also be paid to protecting other structures of the underground pipeline to avoid unnecessary damage. Through the penetrability and precise positioning of the grouting hole, the smooth implementation of subsequent steps can be ensured. The mixing tank is a device for preparing the flowing and solidifying surplus mud grout, while the grouting pump is responsible for transporting the prepared grout into the abandoned pipeline. Connect the mixing tank, the grouting pump, and the slurry delivery pipe to ensure the normal operation of all equipment, enabling efficient and continuous grouting operations. The design of the slurry delivery pipe should meet the fluidity requirements of the flowing and solidifying surplus mud grout to avoid blockage or other non-smooth situations during transportation. In this process, the selection of the grouting pump is particularly crucial. The grouting pump needs to have sufficient pumping capacity to ensure that the flowing and solidifying surplus mud grout can be stably and continuously transported into the abandoned pipeline. Add the composite powder, the deflocculant solution, and the purified water sludge into the mixing tank for mixing. The role of the composite powder is to solidify the purified water sludge to ensure its stability inside the pipeline and avoid separation or deformation of the mud grout due to changes in the pipeline environment; the deflocculant solution is used to reduce the high viscosity of the purified water sludge, making the mixed grout more fluid and easier to be transported into the pipeline through the grouting pump. In addition, the mixing process in the mixing tank needs to be uniform to ensure full fusion of the composite powder with the purified water sludge and the deflocculant solution, avoiding uneven composition or insufficient fluidity of the grout. In this process, the use of an efficient planetary mixer can ensure the mixing effect and avoid uneven distribution or agglomeration of solid particles in the grout. Transport the well-mixed flowing and solidifying surplus mud grout into the abandoned pipeline through the slurry delivery pipe by the grouting pump. The pumping action of the grouting pump enables the grout to smoothly flow into the pipeline, fill the internal voids, and ensure comprehensive and uniform filling of the pipeline. Since the inside of the abandoned pipeline may have complex structures or bends, the grouting process needs to adopt the method of repeated pumping to ensure uniform distribution of the grout and coverage of every corner inside the pipeline. Especially for longer abandoned pipelines, repeated pumping can effectively avoid stratification or uneven flow of the grout due to the long transportation distance. After multiple groutings until the abandoned pipeline is completely filled to ensure its stability and integrity. The repetitiveness of this process ensures uniform distribution of the grout inside the pipeline, which can not only fill the voids but also play a certain sealing role to avoid future environmental pollution or leakage inside the abandoned pipeline.

[0103] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0104] The above embodiments are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a self-leveling material for filling abandoned pipes, characterized in that: The steps include: Obtaining the purified water sludge generated by the purification equipment for treating sewage, and respectively configuring the total mass of the composite powder and the total mass of the debonding agent solution based on the total mass of the purified water sludge; The debinder solution is mixed with the clean water residual mud in the stirring pot, and stirred by a mortar planetary mixer to obtain a clean water residual mud slurry; The composite powder is configured by cement powder and slag powder, the composite powder is added into the water purification residual mud slurry, and a planetary mixer is used to perform mixing for a first preset time to form a flowing solidified residual mud slurry in a flowing state; The fluid solidified residual mud slurry is stored in a column mold, and after being vibrated and rammed on a cement mortar vibration table for a second preset time, the mold is removed to obtain the solidified residual mud filling material.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the slag powder to the cement powder in the composite powder is 0.1-1.

3. The preparation method according to claim 2, characterized in that: Before the cement powder contacts the purified water residual mud slurry, the slag powder is mixed with the cement powder to form an isolation layer between particles of the cement powder.

4. The preparation method according to claim 2, characterized in that: The composite powder is used to maintain the fluidity of the purified water sludge slurry after the purified water sludge is solidified; and the first preset time is set according to the mass ratio of the slag powder to the cement powder.

5. The preparation method according to claim 1, characterized in that: The debonding agent solution is used to remove the high viscosity of the water purification residual mud slurry and improve the fluidity of the flowing solidified residual mud slurry; and the second preset time is set according to the current filling length of the abandoned pipeline.

6. A self-leveling waste pipe filling material produced by the preparation method according to any one of claims 1 to 5, characterized in that: The raw materials include composite powder, debonding agent solution and water purification sludge; the water purification sludge is in a state of high-viscosity slurry, and the components of the water purification sludge include at least one of silicon dioxide, aluminum oxide, iron oxide, potassium oxide, titanium dioxide, phosphorus pentoxide, magnesium oxide and calcium oxide; The mass ratio of the composite powder to the purified water sludge is between 0.20 and 0.30; The mass ratio of the debonding agent solution to the purified water residual sludge is between 0.17 and 0.

19.

7. The self-leveling material for filling abandoned pipes according to claim 6, characterized in that: The slag powder comprises at least one of calcium oxide, silicon dioxide, sulfur trioxide, aluminum oxide, iron oxide, magnesium oxide, sodium oxide and potassium oxide.

8. The self-leveling material for filling abandoned pipes according to claim 6, characterized in that: The cement powder comprises at least one of calcium oxide, silicon dioxide, aluminum oxide, iron oxide, magnesium oxide, sulfur trioxide, potassium oxide and titanium dioxide.

9. The self-leveling material for filling abandoned pipes according to claim 6, characterized in that: The debonding agent solution comprises a sodium citrate solution; the sodium citrate in the sodium citrate solution accounts for 6 to 12 parts by mass, and the water in the sodium citrate solution accounts for 88 to 94 parts by mass.

10. An application method of the self-leveling material for filling waste pipes according to any one of claims 1 to 5, characterized in that: The steps include: A mixing barrel is placed on the ground, and earth is excavated above the abandoned underground pipeline to be treated to form a through grouting hole; Connecting the mixing barrel and the grouting pump to the grouting hole of the abandoned underground pipeline through a grouting pipe; In the stirring barrel, the composite powder, the debonding agent solution and the purified water sludge are stirred and mixed to obtain the fluidized solidified sludge slurry; The flowing solidified residual mud slurry is pumped into the underground abandoned pipeline through a grouting pump and a slurry delivery pipe, and the slurry is repeatedly pumped until the abandoned pipeline is completely filled with slurry.

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