A premixed mortar based on original shield slag and its preparation method and application

Abstract

The present invention relates to a premixed mortar based on undisturbed shield slag, a preparation method thereof, and an application thereof. The premixed mortar comprises the following raw materials in percentage by mass: 60%-85% undisturbed shield slag, 10%-40% alkali-activated cementitious material, 0.5%-3% acrylate gel material, 1%-10% cement, and 3%-15% water. The premixed mortar provided by the present invention can be immediately prepared, solving the problem of time connection between shield slag discharge and on-site use. On-site construction is convenient and operable. The premixed mortar has high compressive strength, excellent impermeability and water retention properties, low apparent density, and low preparation cost, thus achieving the goal of "turning waste into treasure." The present invention provides a new method for large-scale disposal and resource utilization of shield slag, with important economic, environmental, and social benefits.

Description

Technical Field

[0001] The present invention belongs to the fields of building material technology and solid waste treatment, and particularly relates to a premixed mortar based on original shield slag, and a preparation method and application thereof. Background Art

[0002] Shield excavation muck is generated during the shield machine's excavation process to maintain tunnel face stability. After the cutterhead removes the soil in front of it, it enters the soil bin and is transported or pumped to a surface muck pond via screw conveyors, belt conveyors, rail-mounted muck trucks, or pumps. The shield excavation method is typically selected based on the particle size distribution and permeability of the stratum being penetrated. These include slurry shields, earth pressure balance shields, and hard rock TBMs.

[0003] Since foaming agents and high-molecular polymers need to be added to improve the slag during shield tunneling, it becomes hazardous. At the same time, the flow state of earth pressure balance shield slag is different from that of slurry balance shield slag. It is mainly plastic and soft-plastic, usually in a "paste" state, which makes dehydration and screening extremely difficult, making resource utilization more difficult and reducing added value. From a corporate perspective, this will greatly increase construction costs, affect the on-site working environment and safety, and delay construction schedules. From a social perspective, due to the high moisture and mud content of shield slag, open-air stacking is very likely to cause safety accidents such as landslides, polluting the surrounding water and soil environment.

[0004] Therefore, the disposal of shield excavation waste, especially that from earth pressure balance shield excavation, is an unavoidable issue in subway construction. Existing technologies for excavation of shield excavation waste primarily focus on the production of unfired bricks, paving bricks, and fillers, with relatively few involving shield excavation waste mortar. The key challenge in preparing shield excavation waste mortar is how to convert it into ready-mixed mortar for immediate mixing at the construction site, thereby overcoming the time constraints between excavation and on-site use, and ensuring convenient and operable on-site construction.

[0005] If undisturbed shield slag is combined with industrial waste to directly prepare premixed mortar, it will be possible to process and utilize shield slag on a large scale, while reducing production costs and increasing the added value of slag products. By "treating waste with waste" to achieve the goal of "turning waste into treasure," significant economic, environmental, and social benefits can be achieved. However, existing solidification disposal methods, especially alkali-activated cementitious material solidification, suffer from a rapid setting time, and shield slag is difficult to dispose of in a short period of time. Therefore, how to dispose of the large amount of shield slag from shield construction sites at different time periods and locations is a major challenge facing the resource utilization of shield slag. Summary of the Invention

[0006] Based on the above-mentioned technical problems existing in the prior art, the present invention provides a premixed mortar based on original shield slag, aiming to solve the problem that the existing shield slag unburned building materials products have limited ability to absorb shield slag and are unable to dispose of a large amount of shield slag at the shield construction site at different locations in different time periods.

[0007] To achieve the above-mentioned purpose, the premixed mortar based on original shield slag provided by the present invention can be prepared immediately, solving the time connection problem between the discharge of shield slag and on-site use. It is convenient for on-site construction and has good operability. It has high compressive strength, excellent impermeability and water retention performance, low apparent density, low preparation cost, and realizes "turning waste into treasure".

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] A premixed mortar based on undisturbed shield slag, characterized in that the premixed mortar comprises the following raw materials in percentage by mass: 60%-85% of undisturbed shield slag, 10%-40% of alkali-activated gelling material, 0.5%-3% of acrylate gelling material, 1%-10% of cement, and 3%-15% of water;

[0010] The alkali-activated gelling material is composed of the following raw materials in mass percentage: 60%-95% gelling component and 5%-40% alkali activator; the acrylate gel material is composed of the following raw materials in mass percentage: 0-50% acrylate and 100%-50% polyaluminium chloride.

[0011] Preferably, the original shield muck is the original muck that has not been dehydrated and screened and is transported or pumped to the ground muck pool by a screw conveyor, a belt conveyor, or a rail muck car after the shield machine cutter head cuts the soil in front and enters the soil bin.

[0012] Preferably, the original slag is one or more of earth pressure balance shield slag or slurry balance shield slag.

[0013] Preferably, the gelling component is one or more of blast furnace slag, fly ash, silica fume, natural pozzolana, and steel slag.

[0014] Furthermore, the fineness of the gelling component is above 200 mesh.

[0015] Preferably, the alkali activator is one or more of quicklime, sodium carbonate, sodium silicate, sodium metaaluminate, and sodium hydroxide.

[0016] Preferably, the quicklime has a calcium content greater than 75% and a fineness greater than 100 mesh.

[0017] Preferably, the sodium carbonate is in powder form with a fineness greater than 100 mesh.

[0018] Preferably, the sodium silicate is in powder form, has a modulus of 2.0-3.2, and a fineness greater than 100 mesh.

[0019] Preferably, the sodium metaaluminate is in powder form with a fineness greater than 100 mesh.

[0020] Preferably, the sodium hydroxide is analytically pure solid flakes with a purity greater than 99%.

[0021] Preferably, the acrylate is one or more of magnesium acrylate, sodium acrylate, and calcium acrylate.

[0022] Preferably, the polyaluminium chloride (PAC) is in solid powder form.

[0023] Preferably, the cement is Portland cement.

[0024] The present invention also provides a method for preparing the premixed mortar based on the original shield slag as described in any of the above embodiments, comprising the following steps:

[0025] (1) Weigh the raw materials according to their mass percentages, add water to the original shield slag and mix them evenly to obtain material S1;

[0026] (2) mixing and stirring the gelling component, the alkaline activator, the acrylate and the polyaluminium chloride to obtain material S2;

[0027] (3) Add material S2 to material S1 and mix them evenly to obtain shield slag premixed mortar I;

[0028] (4) adding cement to the shield slag premixed mortar I and mixing them evenly to obtain a premixed mortar based on the shield slag;

[0029] Alternatively, include the following steps:

[0030] (1) Weighing raw materials according to mass percentage, adding water to the original shield slag and mixing them evenly to obtain material S1;

[0031] (2) mixing cement, gelling component, alkali activator, acrylate and polyaluminium chloride to obtain material S2;

[0032] (3) Add material S2 to material S1 and mix them evenly to obtain premixed mortar based on shield slag.

[0033] When used on site, the premixed mortar can be directly mixed with cement in proportion and stirred evenly, then applied to the site and cured to obtain a finished shield slag mortar that meets the strength requirements.

[0034] The premixed mortar based on original shield slag described in the present invention can be used as masonry mortar, plastering mortar, floor mortar, waterproof mortar, and other premixed materials.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention prepares premixed mortar by compounding and synergizing shield slag with alkali-activated gelling material, acrylate gel material and cement, thereby obtaining a mortar product with high compressive strength, excellent impermeability and water retention performance and low apparent density. In the present invention, by introducing an acrylate gel material, acrylate and polyaluminum chloride are intricately interwoven together without undergoing hydrolysis or other decomposition reactions. Among them, polyaluminum chloride is an inorganic high molecular polymer that is easily soluble in water and has properties such as adsorption, coagulation, and precipitation. After being dissolved in water, polyaluminum chloride undergoes a polymerization reaction with acrylate to form a network of composite polymer gel phase material. By adding an appropriate amount of acrylate gel material, the generated gel phase material can effectively hinder the reaction of alkali-induced gelling material and avoid strength development. The addition of cement can cause the raw materials to undergo a violent hydration reaction, reducing the moisture content in the shield slag premix material. With the migration of moisture and the shrinkage of the premixed slag material, the existing acrylate gel phase material structure is destroyed, and the alkali-induced gelling material resumes its function, that is, the gelling component reacts with the alkali activator to generate a gelling material that wraps the slag body, gradually improving the solidification strength.

[0037] The method for preparing original shield slag premixed mortar or material provided by the present invention utilizes the strength law characteristics of the process method to solve the operability problem of preparing premixed mortar or material from shield slag.

[0038] In addition, the present invention has low preparation cost and can directly prepare mortar from a large amount of shield slag at the shield construction site, realizing "turning waste into treasure" and providing a new idea for the resource disposal of shield slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a curve diagram of the compressive strength of five schemes in the specific implementation mode of the present invention versus curing time. DETAILED DESCRIPTION

[0040] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0041] The present invention aims to provide a premixed mortar based on original shield slag, wherein the premixed mortar comprises the following raw materials in percentage by mass: 60%-85% original shield slag, 10%-40% alkali-activated gelling material, 0.5%-3% acrylate gelling material, 1%-10% cement and 3%-15% water;

[0042] The alkali-activated gelling material is composed of the following raw materials in mass percentage: 60%-95% gelling component and 5%-40% alkali activator; the acrylate gel material is composed of the following raw materials in mass percentage: 0-50% acrylate and 100%-50% polyaluminium chloride.

[0043] The cement is Portland cement.

[0044] The gelling component is one or more of blast furnace slag, fly ash, silica fume, natural volcanic ash, and steel slag; preferably, the fineness of the gelling component is above 200 mesh.

[0045] The alkali activator is one or more of quicklime, sodium carbonate, sodium silicate, sodium metaaluminate, and sodium hydroxide.

[0046] The acrylate is one or more of magnesium acrylate, sodium acrylate, and calcium acrylate.

[0047] The polyaluminium chloride (PAC) is in the form of solid powder.

[0048] This specific embodiment proposes a premixed mortar based on original shield slag, and also includes research on a preparation method of the shield slag premixed mortar, specifically as follows:

[0049] Five process ratio schemes were designed to investigate the differences in curing strength of different raw material compositions and preparation methods. The specific raw material compositions are as follows:

[0050] Option 1: Original shield slag 68.5%, water 6.5%, blast furnace slag 20.9%, quicklime 1.7%, sodium carbonate 1.5%, sodium silicate 0.9%.

[0051] Option 2: Original shield slag 68.5%, water 6.5%, blast furnace slag 20.9%, quicklime 1.7%, sodium carbonate 1.5%, sodium silicate 0.9%; plus magnesium acrylate 0.25% and polyaluminium chloride 0.81%.

[0052] Option 3: 68.5% original shield slag, 6.5% water, 20.9% blast furnace slag, 1.7% quicklime, 1.5% sodium carbonate, 0.9% sodium silicate; plus 0.25% magnesium acrylate, 0.81% polyaluminium chloride; plus 3.25% cement.

[0053] Option 4: 68.5% original shield slag, 6.5% water, 20.9% blast furnace slag, 1.7% quicklime, 1.5% sodium carbonate, 0.9% sodium silicate; plus 0.16% magnesium acrylate and 0.32% polyaluminium chloride.

[0054] Option 5: Original shield slag 68.5%, water 6.5%, blast furnace slag 20.9%, quicklime 1.7%, sodium carbonate 1.5%, sodium silicate 0.9%; plus magnesium acrylate 0.16%, polyaluminium chloride 0.32%; plus cement 3.25%.

[0055] Among them, the added raw materials in the above-mentioned schemes 2, 3, 4 and 5 are the percentages of the total mass of the raw materials in scheme 1.

[0056] In the above five schemes, the original shield slag was taken from the fully weathered slate shield slag in a section of Changsha Metro Line 6, with an initial moisture content of 41%. During the test, water was first added to the original shield slag and mixed evenly, and then blast furnace slag, quicklime, sodium carbonate, sodium silicate and additional magnesium acrylate, polyaluminum chloride and cement were added and mixed evenly. Finally, the mixture was poured into a 70.7*70.7*70.7mm cubic mold. Cured and demolded under natural conditions at room temperature, the compressive strength of the specimens was tested at 1d, 3d, 7d, 14d, 21d and 28d respectively. After testing, the compressive strength values of the five schemes are shown in Table 1 and Figure 1 shown.

[0057] Table 1 Compressive strength values of five schemes

[0058]

[0059] Figure 1 The following is a graph showing the compressive strength of the five solutions of the present invention as a function of curing time. Combined with the compressive strength values in Table 1, it can be seen that the addition of magnesium acrylate and polyaluminum chloride effectively hinders the alkali-induced reaction, i.e., the development of the compressive strength of the cured specimens. Furthermore, the greater the amount of acrylate gel material added, the greater the reduction in compressive strength. At the same time, curing strength can be regained by further adding Portland cement. For example, a comparison of the compressive strength of Solution 3 or Solution 5 with Solution 1 shows that, before a curing time of 7 days, the compressive strength of Solution 3 and Solution 5 is lower than that of Solution 1. However, after a curing time of 7 days, the compressive strength of Solution 3 and Solution 5 exceeds that of Solution 1.

[0060] Among the five schemes described above, the cured strength gradually increased with increasing curing time. The addition of magnesium acrylate and polyaluminum chloride resulted in virtually no strength increase. For example, the strength of Schemes 2 and 4 was essentially zero at 7 days or earlier. However, the addition of Portland cement to Schemes 2 and 4 promoted rehydration, gradually increasing the strength. For example, the 28-day strength of Schemes 3 and 5 exceeded that of Scheme 1.

[0061] Therefore, this principle can be fully utilized to prepare premixed mortar based on shield tunneling waste. The waste material from on-site excavation is first mixed with water, blast furnace slag, quicklime, sodium carbonate, sodium silicate, magnesium acrylate, polyaluminum chloride, etc., and then cement is added before use.

[0062] The preparation method of the premixed mortar based on the original shield slag proposed in the above specific embodiment includes the following steps:

[0063] (1) Weigh the raw materials according to their mass percentages, add water to the original shield slag and mix them evenly to obtain material S1;

[0064] (2) mixing and stirring the gelling component, the alkaline activator, the acrylate and the polyaluminium chloride to obtain material S2;

[0065] (3) Add material S2 to material S1 and mix them evenly to obtain shield slag premixed mortar I;

[0066] (4) adding silicate cement to the shield slag premixed mortar I and mixing them evenly to obtain a premixed mortar based on the shield slag;

[0067] (5) The premixed mortar based on the shield slag is applied on site and cured to obtain the final finished shield slag mortar product.

[0068] This specific embodiment also includes a premixed mortar based on original shield slag prepared by the above-mentioned preparation method.

[0069] The following further describes in detail relevant embodiments. The original shield slag premixed mortar in the following embodiments can be used as masonry mortar, plaster mortar, floor mortar, waterproof mortar, or other premixed materials.

[0070] Example 1

[0071] A premixed mortar based on undisturbed shield tunneling debris is composed of the following raw materials by weight: 62.75% undisturbed shield tunneling debris, 7.84% water, 15.41% blast furnace slag, 3.41% fly ash, 1.73% quicklime, 1.57% sodium carbonate, 1.41% sodium silicate, 0.39% magnesium acrylate, 1.57% polyaluminum chloride, and 3.92% cement. The undisturbed shield tunneling debris was obtained from the silty clay shield tunneling debris of Tianjin Metro Line 7.

[0072] The preparation steps are as follows:

[0073] (1) Weigh the raw materials according to their mass percentages, add water to the original shield slag and mix them evenly to obtain material S1;

[0074] (2) blast furnace slag, fly ash, quicklime, sodium carbonate, sodium silicate, magnesium acrylate and polyaluminium chloride are mixed and stirred to obtain material S2;

[0075] (3) Add material S2 to material S1 and mix them evenly to obtain shield slag premixed mortar I;

[0076] (4) Add silicate cement to the shield slag premixed mortar I and mix them evenly to obtain a premixed mortar based on shield slag.

[0077] The premixed mortar based on shield slag is applied on site and cured to obtain the final shield slag mortar product.

[0078] Testing showed that the shield-mound premixed mortar produced in Example 1 had an average compressive strength of 3.39 MPa after 7 days and 16.24 MPa after 28 days. According to JGJ70-2009, "Test Methods for Basic Properties of Construction Mortar," the shield-mound premixed mortar had a consistency of 52 mm and a water retention rate of 98.6%.

[0079] Comparative Example 1

[0080] A premixed mortar based on undisturbed shield tunneling slag was prepared as a comparative example to Example 1. The mortar was composed of the following raw materials: undisturbed shield tunneling slag, water, blast furnace slag, fly ash, quicklime, sodium carbonate, sodium silicate, magnesium acrylate, and polyaluminum chloride, with the amounts of each component being the same as in Example 1. The undisturbed shield tunneling slag was obtained from the silty clay shield tunneling slag of Tianjin Metro Line 7.

[0081] The preparation steps are as follows:

[0082] (1) Weigh the raw materials according to their mass percentages, add water to the original shield slag and mix them evenly to obtain material S1;

[0083] (2) blast furnace slag, fly ash, quicklime, sodium carbonate, sodium silicate, magnesium acrylate and polyaluminium chloride are mixed and stirred to obtain material S2;

[0084] (3) Add material S2 to material S1 and mix them evenly to obtain the final premixed mortar based on shield slag.

[0085] According to the test, the average compressive strength of the premixed mortar based on shield slag prepared in Comparative Example 1 was 0 MPa at 7 days and 0.35 MPa at 28 days.

[0086] Example 2

[0087] A premixed mortar based on undisturbed shield tunneling debris is composed of the following raw materials by weight: 64.72% undisturbed shield tunneling debris, 6.47% water, 15.02% blast furnace slag, 2.13% fly ash, 2.27% silica fume, 1.38% quicklime, 1.46% sodium carbonate, 1.46% sodium silicate, 0.35% magnesium acrylate, 0.05% sodium acrylate, 1.45% polyaluminum chloride, and 3.24% cement. The undisturbed shield tunneling debris was obtained from the moderately weathered slate shield tunneling debris from Changsha Metro Line 6.

[0088] The preparation steps are as follows:

[0089] (1) Weigh the raw materials according to their mass percentages, add water to the original shield slag and mix them evenly to obtain material S1;

[0090] (2) blast furnace slag, fly ash, silica fume, quicklime, sodium carbonate, sodium silicate, magnesium acrylate, sodium acrylate and polyaluminium chloride are mixed and stirred to obtain material S2;

[0091] (3) Add material S2 to material S1 and mix them evenly to obtain shield slag premixed mortar I;

[0092] (4) Add silicate cement to the shield slag premixed mortar I and mix them evenly to obtain a premixed mortar based on shield slag.

[0093] The premixed mortar based on shield slag is applied on site and cured to obtain the final shield slag mortar product.

[0094] Testing showed that the shield-mound premixed mortar produced in Example 2 had an average compressive strength of 0.20 MPa after 7 days and an average compressive strength of 10.52 MPa after 28 days. According to JGJ70-2009, "Test Methods for Basic Properties of Construction Mortar," the shield-mound premixed mortar had a consistency of 55 mm and a water retention rate of 98.8%.

[0095] Comparative Example 2

[0096] A premixed mortar based on undisturbed shield tunneling debris was prepared as a comparative example for Example 2. The mortar was composed of the following raw materials: undisturbed shield tunneling debris, water, blast furnace slag, fly ash, silica fume, quicklime, sodium carbonate, sodium silicate, magnesium acrylate, sodium acrylate, and polyaluminum chloride, with the amounts of each component being the same as those in Example 2. The undisturbed shield tunneling debris was obtained from the moderately weathered slate shield tunneling debris from Changsha Metro Line 6.

[0097] The preparation steps are as follows:

[0098] (1) Weigh the raw materials according to their mass percentages, add water to the original shield slag and mix them evenly to obtain material S1;

[0099] (2) blast furnace slag, fly ash, silica fume, quicklime, sodium carbonate, sodium silicate, magnesium acrylate, sodium acrylate and polyaluminium chloride are mixed and stirred to obtain material S2;

[0100] (3) Add material S2 to material S1 and mix them evenly to obtain the final premixed mortar based on shield slag.

[0101] According to the test, the average compressive strength of the premixed mortar based on shield slag prepared in Comparative Example 2 was 0 MPa at 7 days and 0.45 MPa at 28 days.

[0102] Example 3

[0103] A premixed mortar based on undisturbed shield tunneling debris is composed of the following raw materials by weight: 65.25% undisturbed shield tunneling debris, 6.07% water, 15.33% blast furnace slag, 4.40% steel slag, 1.44% quicklime, 1.52% sodium carbonate, 0.98% sodium silicate, 0.46% sodium metaaluminate, 0.38% magnesium acrylate, 0.38% polyaluminium chloride, and 3.79% cement. The undisturbed shield tunneling debris was obtained from the fully weathered slate shield tunneling debris from the Changsha Metro Line 1 North Extension.

[0104] The preparation steps are as follows:

[0105] (1) Weigh the raw materials according to their mass percentages, add water to the original shield slag and mix them evenly to obtain material S1;

[0106] (2) blast furnace slag, steel slag, quicklime, sodium carbonate, sodium silicate, sodium metaaluminate, magnesium acrylate and polyaluminium chloride are mixed and stirred to obtain material S2;

[0107] (3) Add material S2 to material S1 and mix them evenly to obtain shield slag premixed mortar I;

[0108] (4) Add silicate cement to the shield slag premixed mortar I and mix them evenly to obtain a premixed mortar based on shield slag.

[0109] The premixed mortar based on shield slag is applied on site and cured to obtain the final shield slag mortar product.

[0110] Testing showed that the shield-mound premixed mortar produced in Example 3 had an average compressive strength of 2.06 MPa after 7 days and 9.82 MPa after 28 days. According to JGJ70-2009, "Test Methods for Basic Properties of Construction Mortar," the shield-mound premixed mortar had a consistency of 53 mm and a water retention rate of 99.2%.

[0111] Comparative Example 3

[0112] A premixed mortar based on undisturbed shield tunneling debris was prepared as a comparative example for Example 3. The mortar was composed of the following raw materials: undisturbed shield tunneling debris, water, blast furnace slag, steel slag, quicklime, sodium carbonate, sodium silicate, sodium metaaluminate, magnesium acrylate, and polyaluminum chloride, with the amounts of each component being the same as those in Example 3. The undisturbed shield tunneling debris was obtained from fully weathered slate shield tunneling debris from the Changsha Metro Line 1 North Extension.

[0113] The preparation steps are as follows:

[0114] (1) Weigh the raw materials according to their mass percentages, add water to the original shield slag and mix them evenly to obtain material S1;

[0115] (2) blast furnace slag, steel slag, quicklime, sodium carbonate, sodium silicate, sodium metaaluminate, magnesium acrylate and polyaluminium chloride are mixed and stirred to obtain material S2;

[0116] (3) Add material S2 to material S1 and mix them evenly to obtain the final premixed mortar based on shield slag.

[0117] According to the test, the premixed mortar based on shield slag prepared in Comparative Example 3 has an average compressive strength of 0 MPa at 7 days and an average compressive strength of 0.40 MPa at 28 days.

[0118] In addition, other beneficial effects of the present invention are as follows:

[0119] (1) Shield slag premixed mortar does not require dehydration or screening, does not require sintering, has a simple disposal process, low disposal cost, and is low-carbon and environmentally friendly.

[0120] (2) It is universally applicable to different types of shield tunneling debris, can be promoted and replicated, and greatly improves the added value of shield tunneling debris.

[0121] (3) Shield tunneling waste can be disposed of and utilized on a large scale, saving the transportation and disposal costs of shield tunneling waste, reducing construction costs, avoiding the safety risks and hidden dangers brought by waste storage, and achieving good economic, environmental and social benefits.

[0122] It should be noted that the original shield slag used in the above embodiments are all shield slag that are difficult to process. They have a high clay content and a low coarse particle content. The performance of the shield slag premixed mortar prepared is not optimal. If the compressive strength of the premixed mortar prepared from shield slag with a higher sand and gravel content or a lower water content is better than that of the present invention, it should be within the scope of the content of the present invention.

[0123] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The various technical features of the embodiments described above may be combined arbitrarily. To simplify the description, not all possible combinations of the various technical features in the embodiments described above are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A premixed mortar based on original shield slag, characterized in that: The premixed mortar comprises the following raw materials in percentage by mass: 60%-85% of original shield slag, 10%-40% of alkali-activated gelling material, 0.5%-3% of acrylate gelling material, 1%-10% of cement and 3%-15% of water; The alkali-activated gelling material is composed of the following raw materials by mass percentage: 60%-95% of gelling component and 5%-40% of alkali activator; the acrylate gelling material is composed of the following raw materials by mass percentage: 0-50% of acrylate and 100%-50% of polyaluminium chloride; acrylate ≠ 0; The gelling component is one or more of blast furnace slag, fly ash, silica fume, natural pozzolana, and steel slag; The original shield muck is the original muck that has not been dehydrated and screened and is transported or pumped to the ground muck pool by a screw conveyor, belt conveyor, or rail muck truck after the shield machine cutterhead cuts the soil in front and enters the soil bin.

2. The premixed mortar based on original shield slag according to claim 1 is characterized in that: The fineness of the gelling component is above 200 meshes.

3. The premixed mortar based on original shield slag according to claim 1 is characterized in that: The alkali activator is one or more of quicklime, sodium carbonate, sodium silicate, sodium metaaluminate and sodium hydroxide.

4. The premixed mortar based on original shield slag according to claim 1, characterized in that: The acrylate is one or more of magnesium acrylate, sodium acrylate, and calcium acrylate.

5. The premixed mortar based on original shield slag according to claim 1 is characterized in that: The polyaluminium chloride is in the form of solid powder.

6. The premixed mortar based on original shield slag according to claim 1, characterized in that: The cement is Portland cement.

7. The method for preparing premixed mortar based on original shield slag according to any one of claims 1 to 6, characterized in that: The steps include: (1) Weigh the raw materials according to their mass percentages, add water to the original shield slag, and mix and stir evenly to obtain material S1; (2) The gelling component, the alkali activator, the acrylate and the polyaluminium chloride are mixed and stirred uniformly to obtain material S2; (3) Add material S2 to material S1 and mix them evenly to obtain shield slag premixed mortar I; (4) Add cement to the shield slag premixed mortar I and mix them evenly to obtain a premixed mortar based on shield slag; Alternatively, include the following steps: (1) Weigh the raw materials according to their mass percentages, add water to the original shield slag, and mix and stir evenly to obtain material S1; (2) Cement, gelling components, alkali activator, acrylate and polyaluminium chloride are mixed and stirred uniformly to obtain material S2; (3) Add material S2 to material S1 and mix them evenly to obtain a premixed mortar based on shield slag.

8. The use of the premixed mortar based on original shield slag according to any one of claims 1 to 6, characterized in that: The premixed mortar is used as at least one of masonry mortar, plastering mortar, floor mortar and waterproof mortar.

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