High-fluidity muck-based filling material as well as preparation method and application thereof

Abstract

The invention relates to a high-fluidity muck-based filling material and a preparation method and application thereof, the high-fluidity muck-based filling material comprises a gel material, carbon dioxide water-based foam, muck, a composite alkali activator and water, and the gel material comprises fly ash, granulated blast-furnace slag powder and cement. By adopting the synergistic effect of the engineering waste muck, the alkali-activated gel material of the industrial waste and the carbon dioxide water-based foam, the on-site utilization of the engineering waste muck is realized, the material performance is improved and the cement consumption is reduced while the industrial waste is consumed, so that the emission of carbon dioxide is reduced.

Description

Technical Field

[0001] This invention relates to the field of engineering solid waste utilization and carbon neutrality technology, and in particular to a high-flowability slag-based filling material, its preparation method, and its application. Background Technology

[0002] The disposal of excavated waste during urban underground engineering construction is difficult, and the reuse of such waste requires a series of costly disposal measures, including dehydration, transportation, and storage, which also occupy land resources and pose safety hazards. Therefore, the green disposal of engineering solid waste is an urgent engineering problem to be solved. How to enable the on-site utilization of excavated waste from underground engineering as filling material for building trenches is the main problem that this patent aims to solve.

[0003] CN 116120015 A discloses a lightweight foamed concrete. This invention's foamed concrete is prepared from the following raw materials in parts by weight: 100-120 parts cement, 10-20 parts fly ash, 5-10 parts standard sand, 1-3 parts foam stabilizer, 1-3 parts water-reducing agent, 3-5 parts modified animal protein foaming agent, 0.5-1.5 parts polymer fiber, and 0.8-1.2 parts organic adhesive powder. This invention uses fly ash, water-reducing agent, and foaming agent to introduce air into the concrete, resulting in concrete with low dry density and thermal conductivity, and high sound absorption coefficient, while meeting building requirements for compressive strength. However, this patent uses cement, a high-energy-consuming material, and the large CO2 emissions during cement production are detrimental to carbon neutrality.

[0004] CN 112062533 A discloses an alkali-activated recycled micro-powder foamed concrete and its preparation method. This invention comprises the following raw materials in parts by weight: 50-70 parts recycled micro-powder, 10-30 parts granulated blast furnace slag powder, 10-20 parts fly ash, 1-3 parts gypsum, 50-80 parts water, 4-8 parts activator, 1.0-2.0 parts foaming agent, and 0.1-0.2 parts foam stabilizer. This invention addresses the need for solid waste resource utilization by making extensive use of fine powder collected in the air classification process of waste concrete crushing, effectively improving the utilization rate of construction waste. However, this invention uses air as the foaming gas, resulting in alkali-activated recycled micro-powder foamed concrete with low fluidity.

[0005] Existing technologies suffer from high carbon dioxide emissions from cement and low fluidity of filling materials. Therefore, it is necessary to address how to improve the fluidity of filling materials while maintaining their good performance, thereby reducing carbon dioxide emissions, and simultaneously meeting the strength requirements for trench filling. Summary of the Invention

[0006] To solve the above-mentioned technical problems, this invention combines the advantages of engineering waste soil, alkali-activated gel material from industrial waste, and carbon dioxide water-based foam. While ensuring the strength and other properties of the filling material, it improves the fluidity and is suitable for self-flowing filling in ditch backfilling projects. The synergistic effect of the components can achieve both high fluidity and high strength.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a high-flowability slag-based filling material, the high-flowability slag-based filling material comprising: a gel material, carbon dioxide water-based foam, slag, a composite alkali activator, and water, wherein the gel material comprises fly ash, granulated blast furnace slag powder, and cement.

[0009] This invention uses fly ash and granulated blast furnace slag powder as part of the gel material, significantly reducing the amount of cement used and enabling the large-scale consumption of industrial solid waste. At the same time, using slag soil as aggregate enables the on-site utilization of engineering slag soil. By using a composite alkali activator to catalyze the depolymerization and repolymerization reaction of the gel material, the strength of the filling material is improved. Furthermore, the synergistic effect of carbon dioxide water-based foam improves the fluidity of the filling material, solving the technical problem of poor self-leveling effect and compaction dead corners during the backfilling process. While reducing cement usage and carbon dioxide emissions, it can also play a role in sealing carbon dioxide.

[0010] As a preferred technical solution of the present invention, the high-flowability slag-based filling material comprises, by weight, 95-120 parts of gel material, for example, 90 parts, 95 parts, 100 parts, 105 parts, 110 parts, 115 parts, or 120 parts; 31-36 parts of composite alkali activator, for example, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, or 36 parts, preferably 33-35 parts; 550-650 parts of slag, for example, 550 parts, 580 parts, 600 parts, 620 parts, or 650 parts, preferably 580-650 parts; 12-17 parts of carbon dioxide water-based foam, for example, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, or 17 parts, preferably 14-17 parts; and the balance being water.

[0011] Preferably, the gel material comprises, by weight, 55-65 parts of fly ash, for example, 55, 58, 60, 62 or 65 parts, preferably 58-65 parts; 35-45 parts of granulated blast furnace slag powder, for example, 35, 38, 40, 42 or 45 parts, preferably 35-42 parts; and 5-10 parts of cement, for example, 5, 6, 7, 8, 9 or 10 parts, preferably 8-10 parts.

[0012] This invention optimizes the proportions of each component, thereby further improving the fluidity and compressive strength of the finished filling material, while ensuring a lower cement content. It makes full use of industrial solid waste and engineering spoil, meeting construction application requirements while improving economic efficiency and environmental friendliness.

[0013] Preferably, the mass ratio of water to gel material in the high-flowability slag-based filling material is 0.5 to 0.6, for example, it can be 0.5, 0.52, 0.54, 0.55 or 0.60, etc.

[0014] This invention optimizes the macroscopic pore structure inside the filling material by selecting the optimal mass ratio of water and gel material, providing a better dispersion environment for foam and solid particles, improving the stability of foam and the uniformity of solid particle dispersion, and promoting the hydration process of gel material, thereby improving fluidity and compressive strength.

[0015] As a preferred embodiment of the present invention, the carbon dioxide water-based foam comprises a foaming liquid and a foaming gas.

[0016] Preferably, the foaming liquid comprises, by weight, 10-20 parts of sodium dodecyl sulfate, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 parts, 3-6 parts of carboxypropyl methylcellulose, for example, 3, 4, 5 or 6 parts, and 5000 parts of water.

[0017] Preferably, the foaming gas is carbon dioxide gas with a volume concentration of 30-50%, for example, it can be 30%, 35%, 40%, 45% or 50%, etc.

[0018] This invention improves the stability of bubbles and thus enhances the fluidity of filling materials by optimizing the volume concentration of carbon dioxide in the foaming gas.

[0019] As a preferred technical solution of the present invention, the slag is obtained by pre-treatment of engineering slag generated from underground operations.

[0020] Preferably, the underground operation includes shield tunneling, drill-and-blast, open-cut excavation, or pipe jacking.

[0021] Preferably, the moisture content of the pretreated slag is ≤10wt%, for example, it can be 1wt%, 3wt%, 5wt%, 8wt%, 10wt%, etc.

[0022] Preferably, the particle size of the pretreated slag is ≤0.3mm.

[0023] As a preferred embodiment of the present invention, the fly ash contains 45wt%~49wt% SiO2, 32wt%~36wt% Al2O3, ≤5wt% MgO, and ≤5wt% Fe2O3.

[0024] As a preferred technical solution of the present invention, the granulated blast furnace slag powder includes S95 grade granulated blast furnace slag powder.

[0025] Preferably, the granulated blast furnace slag powder contains 33wt%~37wt% SiO2, 32wt%~35wt% CaO, 14wt%~18wt% Al2O3, and 11wt%~14wt% MgO.

[0026] As a preferred technical solution of the present invention, the cement is ordinary Portland cement with a grade of 42.5.

[0027] Preferably, the cement has a SiO2 content of 21wt%~22wt%, a CaO content of 64-66wt%~25wt%, an Al2O3 content of 4wt%~5wt%, and an MgO content of 3wt%~4wt%.

[0028] As a preferred technical solution of the present invention, the composite alkali activator comprises 26 to 29 parts by mass of water glass solution, such as 26, 26.5, 27, 28 or 29 parts, and 5 to 7 parts of sodium hydroxide, such as 5, 5.5, 6, 6.5 or 7 parts.

[0029] Preferably, the water glass solution has a modulus of 2.8 to 3.5, a Baumé degree of 35 to 45, a Na2O content of 9.25 wt%, and a SiO2 content of 29 wt%.

[0030] In a second aspect, the present invention provides a method for preparing a high-flowability slag-based filling material as described in the first aspect. The preparation method includes: mixing a gel material with slag in parts by weight, then adding water and stirring to form a slurry, and then sequentially adding a composite alkali activator and a carbon dioxide water-based foam, and stirring thoroughly to obtain the high-flowability slag-based filling material.

[0031] Preferably, the dry mixing and thorough stirring are sufficient to ensure that the materials are thoroughly mixed. The specific stirring time can be selected and optimized according to the state of the materials, and is not further limited here.

[0032] Preferably, the slag is pretreated, which includes dewatering, mechanically crushing and screening the engineering slag generated during the operation to obtain the slag.

[0033] Preferably, the dehydration method includes, but is not limited to, sun drying, and can remove the moisture contained in the construction waste soil to meet the moisture content requirements; no further limitation is made here.

[0034] Preferably, the preparation of the carbon dioxide water-based foam includes weighing sodium dodecyl sulfate and carboxypropyl methylcellulose in parts by weight and dissolving them in water, and then introducing foaming gas to foam the foam.

[0035] Preferably, the foaming is carried out using a foaming machine. The parameters of the foaming machine, such as gas pressure and temperature, can be selected and optimized according to the foaming ratio and stability, and are not further limited here.

[0036] Preferably, the preparation of the composite alkali activator includes dissolving sodium hydroxide in water glass solution in parts by weight.

[0037] Preferably, after the sodium hydroxide is fully dissolved, water is added to bring the total weight back to the initial weight to compensate for the exothermic water loss.

[0038] Thirdly, the present invention provides an application of the high-flowability slag-based backfill material as described in the first aspect, the application including applying the high-flowability slag-based backfill material to slag pit backfilling projects.

[0039] Compared with the prior art, the present invention has at least the following beneficial effects:

[0040] (1) This invention uses two industrial solid wastes, fly ash and granulated blast furnace slag powder, to prepare the material system. The material system avoids the use of traditional high-energy-consuming building materials such as silicate cement on a large scale. The proportion of raw material solid waste can reach more than 50wt%, which can consume a large amount of industrial solid waste and has a low cost.

[0041] (2) The high fluidity slag-based filling material provided by the present invention has the characteristics of high fluidity, high compressive strength, self-leveling, self-compacting, and room temperature preparation; it can absorb a large amount of slag and effectively avoid the problems of insufficient compaction of traditional backfill materials and the presence of compaction dead corners in some narrow backfill areas.

[0042] (3) The present invention utilizes carbon dioxide to prepare carbon dioxide water-based foam alkali-activated high-fluidity slag fertilizer trench filling material, which not only gives full play to the carbon dioxide curing effect of fertilizer trench filling material, but also realizes the function of carbon dioxide capture and storage. Attached Figure Description

[0043] Figure 1 This is a flowchart illustrating the preparation process of the high-flowability slag-based filling material provided in Embodiment 1 of the present invention;

[0044] Figure 2This is a trend graph showing the change in density grade of the high-flowability slag-based filling material provided in Embodiments 1-5 of the present invention with the mass ratio of water and gel material.

[0045] Figure 3 This is a trend graph showing the change in the flowability of the high-flowability slag-based filling material provided in Embodiments 1-5 of the present invention with the mass ratio of water and gel material;

[0046] Figure 4 This is a trend graph showing the compressive strength of the high-flowability slag-based filling material provided in Examples 1-5 of the present invention as a function of the mass ratio of water and gel material. Detailed Implementation

[0047] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0048] The granulated blast furnace slag powder used in the following examples is S95 granulated blast furnace slag powder produced in Wuhan, Hubei Province. The content is 33wt%~37wt%, and the CaO content is 32wt%~35wt%. The content is 14wt%~18wt%, and the MgO content is 11wt%~14wt%.

[0049] The cement used was silicate cement with a grade of 42.5 produced by Shanghai Tongtai Fertilizer Filling Material Admixture Co., Ltd., with a SiO2 content of 21wt%~22wt%, CaO content of 64-66wt%~25wt%, Al2O3 content of 4wt%~5wt%, and MgO content of 3wt%~4wt%.

[0050] In some embodiments, the foaming machine is an F100 model foaming machine manufactured by Jiulongpo District Yuzhuo Building Materials Business Department.

[0051] The selected water glass solution has a modulus of 2.8M to 3.5M, a Baumé degree of 35 to 45, a Na2O content of 9.25 wt%, and a SiO2 content of 29 wt%; the purity of sodium hydroxide is not less than 96 wt%.

[0052] Example 1

[0053] This embodiment provides a high-flowability slag-based filling material, which includes: gel material, carbon dioxide water-based foam, slag, composite alkali activator and water, wherein the gel material includes fly ash, granulated blast furnace slag powder and cement;

[0054] The high-flowability slag-based filling material comprises, by weight, 60 grams of fly ash, 40 grams of granulated blast furnace slag powder, 5 grams of cement, 33.2 grams of composite alkali activator, 600 grams of slag, 12 grams of carbon dioxide water-based foam, and 35.25 grams of water, with a water-to-gel material mass ratio of 0.45; wherein the composite alkali activator contains 27.6 grams of water glass solution and 5.6 grams of sodium hydroxide, and the carbon dioxide water-based foaming liquid contains 3 g / L sodium dodecyl sulfate and 1 g / L carboxypropyl methylcellulose;

[0055] like Figure 1 As shown, the high-flowability slag-based filling material is prepared using the following steps:

[0056] (1) The excavated jacking soil is first dried, and then the dried soil is mechanically crushed and passed through a 0.3mm standard sieve.

[0057] (2) Weigh out the foaming agent sodium dodecyl sulfate, the foam stabilizer carboxypropyl methylcellulose and water by weight. Mix the sodium dodecyl sulfate and the foam stabilizer carboxypropyl methylcellulose evenly and then dissolve them in water to prepare the foaming liquid.

[0058] (3) Weigh fly ash, granulated blast furnace slag powder, cement and slag according to weight, and dry mix them for 1 minute to obtain a mixture;

[0059] (4) Weigh water glass solution and solid sodium hydroxide according to the weight parts, mix and stir evenly, cool to room temperature after fully dissolving, and add water to the initial weight to replenish the exothermic evaporation water volume to obtain composite alkali activator. Weigh water according to the weight parts and add it to the mixture, then stir for 30s until it is evenly mixed to obtain mixed slurry. Add composite alkali activator to mixed slurry and stir for 30s to obtain alkali activated filling material.

[0060] (5) Pass the foaming liquid into the inlet pipe of the foaming machine, connect the air inlet of the foaming machine to a 40% carbon dioxide gas cylinder, start the foaming machine to foam, weigh the carbon dioxide water-based foam according to the weight ratio and add it to the alkali-activated filling material obtained in step (4), stir for 30 seconds until it is evenly mixed, and obtain a high-fluidity slag-based filling material.

[0061] Example 2

[0062] This embodiment provides a high-flowability slag-based filling material, which includes: gel material, carbon dioxide water-based foam, slag, composite alkali activator and water, wherein the gel material includes fly ash, granulated blast furnace slag powder and cement;

[0063] The high-flowability slag-based filling material comprises, by weight, 60g of fly ash, 40g of granulated blast furnace slag powder, 5g of cement, 32.2g of composite alkali activator, 600g of slag, 14g of carbon dioxide water-based foam, and 45.5g of water, with a water-to-gel material mass ratio of 0.50. The composite alkali activator contains 26.8g of water glass solution and 5.4g of sodium hydroxide. The foaming solution of the carbon dioxide water-based foam contains 3g / L sodium dodecyl sulfate and 1g / L carboxypropyl methylcellulose. The preparation method is the same as in Example 1.

[0064] Example 3

[0065] This embodiment provides a high-flowability slag-based filling material, which includes: gel material, carbon dioxide water-based foam, slag, composite alkali activator and water, wherein the gel material includes fly ash, granulated blast furnace slag powder and cement;

[0066] The high-flowability slag-based filling material comprises, by weight, the following raw materials: 60g fly ash, 40g granulated blast furnace slag powder, 5g cement, 33.2g composite alkali activator, 600g slag, 16g carbon dioxide water-based foam, and 48.95g water, with a water-to-gel material mass ratio of 0.55; wherein the composite alkali activator contains 28.6g water glass solution and 5.6g sodium hydroxide, and the carbon dioxide water-based foaming liquid contains 3g / L sodium dodecyl sulfate and 1.2g / L carboxypropyl methylcellulose; the preparation method is the same as in Example 1.

[0067] Example 4

[0068] This embodiment provides a high-flowability slag-based filling material, which includes: gel material, carbon dioxide water-based foam, slag, composite alkali activator and water, wherein the gel material includes fly ash, granulated blast furnace slag powder and cement;

[0069] The high-flowability slag-based filling material comprises, by weight, 60g of fly ash, 40g of granulated blast furnace slag powder, 10g of cement, 33.2g of composite alkali activator, 600g of slag, 17g of carbon dioxide water-based foam, and 55.8g of water, with a water-to-gel material mass ratio of 0.60; wherein the composite alkali activator contains 28.6g of water glass solution and 5.6g of sodium hydroxide, and the carbon dioxide water-based foaming liquid contains 3g / L of sodium dodecyl sulfate and 2g / L of carboxypropyl methylcellulose; the preparation method is the same as in Example 1.

[0070] Example 5

[0071] This embodiment provides a high-flowability slag-based filling material, which includes: gel material, carbon dioxide water-based foam, slag, composite alkali activator and water, wherein the gel material includes fly ash, granulated blast furnace slag powder and cement;

[0072] The high-flowability slag-based filling material comprises, by weight, 65g of fly ash, 35g of granulated blast furnace slag powder, 10g of cement, 33.8g of composite alkali activator, 550g of slag, 17g of carbon dioxide water-based foam, and 60.45g of water, with a water-to-gel material mass ratio of 0.65. The composite alkali activator contains 28.1g of water glass solution and 5.7g of sodium hydroxide. The carbon dioxide water-based foaming liquid contains 3g / L sodium dodecyl sulfate and 2g / L carboxypropyl methylcellulose. The preparation method is the same as in Example 1.

[0073] Example 6

[0074] This embodiment provides a high-flowability slag-based filling material, which includes: gel material, carbon dioxide water-based foam, slag, composite alkali activator and water, wherein the gel material includes fly ash, granulated blast furnace slag powder and cement;

[0075] The high-flowability slag-based filling material comprises, by weight, 55g of fly ash, 45g of granulated blast furnace slag powder, 5g of cement, 33.2g of composite alkali activator, 600g of slag, 14g of carbon dioxide water-based foam, and 45.5g of water, with a water-to-gel material mass ratio of 0.5. The composite alkali activator contains 27.6g of water glass solution and 5.6g of sodium hydroxide. The carbon dioxide water-based foam contains 3g / L sodium dodecyl sulfate and 1g / L carboxypropyl methylcellulose. The preparation method is the same as in Example 1.

[0076] Example 7

[0077] This embodiment provides a high-flowability slag-based filling material, which includes: gel material, carbon dioxide water-based foam, slag, composite alkali activator and water, wherein the gel material includes fly ash, granulated blast furnace slag powder and cement;

[0078] The high-flowability slag-based filling material comprises, by weight, 60 g of fly ash, 40 g of granulated blast furnace slag powder, 8 g of cement, 34.2 g of composite alkali activator, 550 g of slag, 15 g of carbon dioxide water-based foam, and 44.4 g of water, with a water-to-gel material mass ratio of 0.55. The composite alkali activator contains 28.6 g of water glass solution and 5.8 g of sodium hydroxide. The carbon dioxide water-based foaming liquid contains 3 g / L sodium dodecyl sulfate and 1.2 g / L carboxypropyl methylcellulose. The preparation method is the same as in Example 1.

[0079] Example 8

[0080] This embodiment provides a high-flowability slag-based filling material, which includes: gel material, carbon dioxide water-based foam, slag, composite alkali activator and water, wherein the gel material includes fly ash, granulated blast furnace slag powder and cement;

[0081] The high-flowability slag-based filling material comprises, by weight, 58 g of fly ash, 42 g of granulated blast furnace slag powder, 10 g of cement, 35.2 g of composite alkali activator, 650 g of slag, 16 g of carbon dioxide water-based foam, and 50 g of water, with a water-to-gel material mass ratio of 0.60. The composite alkali activator contains 29.6 g of water glass solution and 6.0 g of sodium hydroxide. The carbon dioxide water-based foam contains 3 g / L sodium dodecyl sulfate and 1.2 g / L carboxypropyl methylcellulose. The preparation method is the same as in Example 1.

[0082] Example 9

[0083] This embodiment provides a high-flowability slag-based filling material. Except for the weight of the carbon dioxide water-based foam being 11 grams and the water usage being increased to 36.25 grams to ensure the mass ratio of water to gel material, the high-flowability slag-based filling material is the same as that in Embodiment 1.

[0084] Example 10

[0085] This embodiment provides a high-flowability slag-based filling material. Except for the weight of the carbon dioxide water-based foam being 18 grams and the water usage being increased to 39.25 grams to ensure the mass ratio of water to gel material, the high-flowability slag-based filling material is the same as in Embodiment 1.

[0086] Example 11

[0087] This embodiment provides a high-flowability slag-based filling material, which is the same as that in Embodiment 1 except that the weight of the composite alkali activator is 30 grams.

[0088] Example 12

[0089] This embodiment provides a high-flowability slag-based filling material, which is the same as that in Embodiment 1 except that the weight of the composite alkali activator is 37 grams.

[0090] Example 13

[0091] This embodiment provides a high-flowability slag-based filling material. Except for the foaming gas, which is carbon dioxide gas with a volume fraction of 20%, the high-flowability slag-based filling material is the same as that in Embodiment 1.

[0092] Example 14

[0093] This embodiment provides a high-flowability slag-based filling material. Except for the foaming gas, which is carbon dioxide gas with a volume fraction of 60%, the high-flowability slag-based filling material is the same as that in Embodiment 1.

[0094] Comparative Example 1

[0095] This comparative example provides a slag-based filling material, which includes: a gel material, an air-water-based foam, slag, a composite alkali activator, and water. The gel material includes fly ash, granulated blast furnace slag powder, and cement.

[0096] The high-flowability slag-based filling material comprises, by weight, 60g of fly ash, 40g of granulated blast furnace slag powder, 5g of cement, 33.2g of composite alkali activator, 600g of slag, 12g of water-based foam, and 35.25g of water, with a water-to-gel material mass ratio of 0.45. The composite alkali activator contains 27.6g of water glass solution and 5.6g of sodium hydroxide. The water-based foaming liquid contains 3g / L sodium dodecyl sulfate and 1g / L carboxypropyl methylcellulose. The preparation method is the same as in Example 1, except that 40% carbon dioxide gas in Example 1 is replaced with air.

[0097] Comparative Example 2

[0098] This comparative example provides a slag-based filling material, which includes: gel material, carbon dioxide water-based foam, slag, composite alkali activator and water. The gel material includes fly ash and cement. Except for replacing the granulated blast furnace slag powder in the gel material with an equal mass of fly ash, the rest is the same as in Example 1.

[0099] Comparative Example 3

[0100] This comparative example provides a slag-based filling material, which includes: gel material, carbon dioxide water-based foam, slag, composite alkali activator and water. The gel material includes granulated blast furnace slag powder and cement. Except for replacing the fly ash in the gel material with an equal mass of granulated blast furnace slag powder, the rest is the same as in Example 1.

[0101] Comparative Example 4

[0102] This comparative example provides a slag-based filling material, which includes: gel material, carbon dioxide water-based foam, slag, alkali activator and water. Except for replacing the composite alkali activator with an equal mass of single water glass alkali activator, the rest are the same as in Example 1.

[0103] Test methods

[0104] The fill materials provided in Examples 1-14 and Comparative Examples 1-4 were subjected to flowability tests, compressive strength tests, water absorption tests, and dry density tests, respectively. The test results are shown in Table 1.

[0105] (1) Flowability test

[0106] The fluidity test was conducted in accordance with the "Technical Specification for Application of Foamed Fertilizer Tank Filling Materials" (JGJ / T341-2014) to evaluate the fluidity of alkali slag foamed fertilizer tank filling materials. Freshly mixed slurry was poured into a hollow cylinder with an inner diameter and height of 80 mm. The outside of the cylinder was gently tapped with a flat-edged knife, and the end was then scraped flat. The cylinder was then slowly lifted vertically and allowed to stand for 60 seconds. The maximum horizontal diameter was measured with a vernier caliper. The test was repeated three times, and the arithmetic mean was taken as the fluidity of the foamed fertilizer tank filling material, in mm.

[0107] (2) Compressive strength test

[0108] The compressive strength test was conducted according to the "Foam Fertilizer Tank Filling Material" (JG / T266-2011). The testing equipment was an electronic universal testing machine. Three specimens were first dried to constant weight, and the area of ​​the compressive surface A (unit: ...) was measured and calculated. ), continuously and uniformly pressurize until the specimen fails, record the maximum failure load F (unit: N), and the compressive strength f is calculated according to the formula Calculations are performed, with units in MPa.

[0109] (3) Water absorption rate test

[0110] The water absorption rate test was conducted according to the "Foam Fertilizer Tank Filling Material" (JG / T266-2011). Three specimens were placed in a drying oven and dried to constant weight at (60±5)℃. The water absorption rate was the ratio of the mass difference before and after drying to the mass after drying. The water absorption rate was calculated using the formula... calculate;

[0111] (4) Dry density test

[0112] The dry density test was conducted according to the standard for foam fertilizer tank filling materials (JG / T266-2011). A set of 100mm×100mm×100mm samples was taken, and their length, width, and height were measured to calculate the sample volume. (unit: The specimen was placed in an oven at (60±5)℃ and dried for 4 hours each time until the difference between two consecutive drying times was ≤1g. After the specimen was removed and cooled to room temperature, the dried mass was measured. (Unit: g). Dry density According to the formula = × Calculation, unit: kg / .

[0113] Test Results

[0114] Table 1

[0115]

[0116] The test results show that:

[0117] (1) As can be seen from Examples 1 to 8, the present invention can obtain a high-flowability and high-strength slag-based filling material through the synergistic effect of engineering waste slag, alkali-activated gel material from industrial waste, and carbon dioxide water-based foam. As can be seen from Examples 1-5, the mass ratio of water to gel material affects the flowability, density grade, and compressive strength of the material. When the water-cement ratio is between 0.45 and 0.60, the higher the water-cement ratio, the greater the compressive strength at different ages. When the water-cement ratio is low, the slurry is viscous, the cementitious material is not completely wetted, and when the slurry and foam are stirred, the friction force on the foam increases, which easily causes the foam to be squeezed and burst. At the same time, when there is less water inside the slurry, it will affect the hydration process of the cementitious material, which is not conducive to the development of later strength. When the cementitious material is too short of water, it will also absorb water from the bubble liquid film, making the foam liquid film thinner and further reducing the stability of the foam. Therefore, the compressive strength increases with the increase of the water-cement ratio. When the water-cement ratio is too high, the consistency of the slurry decreases, delaying both initial and final setting times. Simultaneously, the thinner slurry weakens the binding force on the foam, making it easier for the foam to move and aggregate within the mixed slurry. This results in slower early-stage pore wall strength development, and the increased fusion and aggregation of foam within the concrete leads to more interconnected and through-hole pores, deteriorating the macroscopic pore structure and reducing compressive strength. Furthermore, as the water-cement ratio increases, the fluidity increases. This is primarily because a higher water content in the slurry provides a better dispersion environment for the foam and solidified particles, making the slurry and foam easier to mix evenly. The optimized water-cement ratio in this invention allows the material to achieve better overall performance.

[0118] (2) As can be seen from Examples 1 and 9-14, by further optimizing the dosage of carbon dioxide water-based foam and composite alkali activator and the carbon dioxide concentration of foaming gas, the present invention can achieve better fluidity and compressive strength, and improve the synergistic effect of multiple components. When the amount of carbon dioxide water-based foam is too small, it cannot fully play the role of reducing friction and improving fluidity. When the amount of carbon dioxide water-based foam is too large, the foam contact angle squeezed together is larger, the foam movement is difficult, and the fluidity of the slurry is worse. The appropriate content of alkali activator increases the compressive strength and fluidity. The silicon-oxygen bonds with large bond energy in the reaction products can significantly improve the mechanical properties of the material. The degree of polymerization of silicate ions is improved. These silicate ions form more chain or network silicate structures. These structures can be adsorbed on the surface of particles such as fly ash and slag. By forming a steric hindrance effect, the friction and agglomeration between particles are effectively reduced. The optimization of carbon dioxide concentration enhances the stability of carbon dioxide water-based foam, reduces the viscosity of the slurry, and thus improves the fluidity of concrete.

[0119] (3) As can be seen from Example 1 and Comparative Examples 1-4, the present invention improves the overall performance of materials through the synergistic effect of alkali-activated gel materials and carbon dioxide water-based foam. When carbon dioxide water-based foam is incorporated, it forms better fluidity than when air water-based foam is incorporated. When any one of the gel materials is missing, the performance of the resulting filling material decreases.

[0120] In summary, this invention utilizes the synergistic effect of alkali-activated gel materials from engineering waste soil and industrial waste, along with carbon dioxide-based foam, to obtain a high-flowability and high-strength slag-based filling material. It consumes a large amount of engineering and industrial waste, and the resulting filling material meets the requirements for building backfilling. The solution is green and economical, reducing carbon dioxide emissions caused by the extensive use of cement in the filling material.

[0121] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A high flow, slag-based fill material, characterized in that, The high-fluidity slag-soil-based filling material comprises a gel material, a carbon dioxide water-based foam, slag soil, a composite alkali activator and water, and the gel material comprises fly ash, granulated blast furnace slag powder and cement.

2. The high-flowing, soil-based fill material of claim 1, wherein, The mass ratio of water to the gel material in the high-fluidity slag-soil-based filling material is 0.5-0.

6.

3. The high-flowing, soil-based fill material of claim 1, wherein, The carbon dioxide water-based foam comprises a foaming liquid and a foaming gas, and the foaming gas is carbon dioxide gas with a volume concentration of 30-50%.

4. The high-flowing, soil-based fill material of claim 1, wherein, The slag soil is engineering slag soil generated in underground operation after pretreatment, and the particle size of the pretreated slag soil is ≤0.3 mm.

5. The high-flowing, soil-based fill material of claim 1, wherein, The content of SiO2 in the fly ash is 45wt%-49wt%, the content of Al2O3 is 32wt%-36wt%, the content of MgO is ≤5wt%, and the content of Fe2O3 is ≤5wt%.

6. The high-flowing, slag-surfaced fill material of claim 1, wherein, The granulated blast furnace slag powder comprises S95-grade granulated blast furnace slag powder.

7. The high-flowing, soil-based fill material of claim 1, wherein, The cement is ordinary Portland cement with a grade of 42.

5.

8. The high-flowing, soil-based fill material of claim 1, wherein, The composite alkali activator comprises 26-29 parts of water glass solution and 5-7 parts of sodium hydroxide by mass fraction.

9. A method of producing a high-flowability soil-based filling material according to any one of claims 1 to 8, characterized in that, The preparation method comprises uniformly dry mixing the gel material and the slag soil by weight fraction, adding water to stir to form a slurry, and then sequentially adding the composite alkali activator and the carbon dioxide water-based foam and fully stirring and mixing, respectively, to obtain the high-fluidity slag-soil-based filling material.

10. Use of a high-flowing-slurry-soil-based filling material according to any one of claims 1 to 8, characterized in that, The application comprises applying the high-fluidity slag-soil-based filling material to fat trench backfill engineering.

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