Light waste residue high-flow-state concrete for roadbed and preparation method of light waste residue high-flow-state concrete

Abstract

The invention discloses light waste residue high-flow-state concrete for a roadbed and a preparation method of the light waste residue high-flow-state concrete. The light waste residue high-flow-state concrete comprises 51-56 wt% of light waste residue particles, 24-28 wt% of a gel material and 16-25 wt% of water, the gel material is cement or a mixture of cement and any one of fly ash and light waste residue powder. According to the invention, resource utilization of solid wastes can be realized, the roadbed material which is easy to construct, good in stability and controllable in cost can be prepared, and potential safety hazards of roads are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and specifically relates to a lightweight waste residue high-fluidity concrete for subgrade and a preparation method thereof. Background Art

[0002] Building a transportation power is a major strategic decision based on national conditions, focusing on the overall situation, and facing the future. Forming a modern comprehensive transportation system and building an urban and rural regional transportation network are important supports for building a modern and powerful country in an all-round way. As an important part of road engineering, improving the overall stability and comprehensive disaster resistance ability of the subgrade is crucial for the safety of traffic engineering. Traditional subgrades are mainly earth subgrades, which have problems such as shortage of earth resources, high construction costs, and insufficient strength. These problems not only increase the difficulty of road construction, but also may pose potential threats to the safety and stability of the road, including serious accidents such as subgrade collapse. The subgrade collapse accident that occurred in the Chayang section of the Meilong Expressway in 2024 sounded the alarm for the safety of earth subgrades.

[0003] As a new road engineering construction technology, the fluidized subgrade has the advantages of simple and controllable construction, high strength and stability. CN202310048435.2, "A fluidized solidified soil prepared from industrial waste slag and a method thereof", proposes a method for preparing fluidized solidified soil from industrial waste slag, but the source of slag resources is limited and has regional limitations. CN201710321058.X, "A lightweight environmental protection filling foam fluidized fly ash for subgrade and a preparation method thereof", proposes a filling method for preparing fluidized foam concrete using solid wastes such as fly ash, but there are also problems such as difficult control of volume stability and high use costs.

[0004] For waste residues such as sludge gasification slag, biomass power plant ash slag, and power plant fluidized bed ash slag produced by industries such as sewage treatment plants and biomass power plants, the particle size distribution is close to that of concrete aggregates, and at the same time, they have the characteristics of being lightweight and porous. However, their particle strength is low, which limits their application in concrete and there is a large pressure for disposal. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a lightweight waste residue high-fluidity concrete for subgrade and a preparation method thereof.

[0006] The technical solution of the present invention is: a lightweight waste residue high-fluidity concrete for subgrade, comprising 51-56 wt% of lightweight waste residue particles, 24-28 wt% of gel material, and 16-25 wt% of water; the gel material is cement, or a mixture of cement and any one of fly ash and lightweight waste residue powder.

[0007] Furthermore, the light waste residue particles are one of the sludge gasification slag produced by the pyrolysis gasification of a sewage treatment plant, the biomass ash residue produced by a biomass power plant, or the fluidized bed ash residue produced by a thermal power plant, and the particle size of the light waste residue particles is 2.36 - 20 mm.

[0008] Note: The main chemical components of fly ash, sludge gasification slag, and fluidized bed ash residue of a power plant are SiO 2 , and the main chemical component of the biomass power plant ash residue is silicate. Since the waste residues such as sludge gasification slag, biomass power plant ash residue, and fluidized bed ash residue of a power plant produced by industries such as sewage treatment plants and biomass power plants have a particle size distribution close to that of concrete aggregates, the resource utilization of solid waste can be achieved by using these waste residues.

[0009] The fluidity of concrete is crucial for pouring and vibrating during the construction process. If the aggregate particle size is too large, it will lead to an increase in the internal friction of the concrete, a decrease in fluidity, causing difficulties in construction, and will also result in too many voids inside the concrete structure, affecting the compactness of the structure. While if the aggregate particle size is too small, it may lead to an increase in the shrinkage of the concrete, increasing the risk of cracks. Therefore, using the light waste residue within the above particle size range as the aggregate can ensure the stability and durability of the concrete structure.

[0010] Furthermore, the light waste residue powder is any one of the sludge gasification slag produced by the pyrolysis gasification of a sewage treatment plant, the biomass ash residue produced by a biomass power plant, or the fluidized bed ash residue produced by a thermal power plant that has been ground by a ball mill and passed through a 500 - 600 mesh sieve.

[0011] Note: The resource utilization of solid waste can be achieved by using these waste residues as the raw materials of the gel material. Using the above light waste residue powder can meet the functional requirements of the gel material, thereby obtaining a light waste residue high - fluidity concrete with excellent performance.

[0012] Furthermore, in the gel material, the mixing ratio of cement and fly ash is 5 - 15 wt% cement and 85 - 95 wt% fly ash; the mixing ratio of cement and light waste residue powder is 5 - 15 wt% cement and 85 - 95 wt% light waste residue powder.

[0013] Note: The gel material composed of the above ratio can ensure the performance of the concrete while reducing the cement consumption. By using fly ash and sludge gasification slag powder to fill the voids in the cement colloid, the compactness of the concrete is increased, thereby improving the compressive strength, crack resistance strength, and frost resistance of the concrete. And adding fly ash and sludge gasification slag powder in the above proportion can improve the fluidity, cohesion, and water retention of the concrete mixture, making the concrete mixture easy to pump and pour into shape, and reducing the time - dependent loss of slump.

[0014] Further, the cement is Portland cement with a strength grade of 42.5.

[0015] Note: 42.5 Portland cement has relatively high compressive strength, high early strength, moderate setting time, small bleeding water volume, which is beneficial to the mixing, pouring and vibration of concrete, and has excellent durability. Compared with other special cements, 42.5 Portland cement has a relatively high cost performance, can meet the needs of most construction projects, and at the same time reduces material costs.

[0016] Further, the light waste residue particles need to be pre-wetted with water, and the water consumption for the pre-wetting treatment is 50 - 80% of the water absorption of the light waste residue particles.

[0017] Note: By using the above water consumption for pre-wetting the light waste residue particles, the light waste residue particles can be better combined with the cement paste. The pre-wetted light waste residue particles can better absorb and retain moisture, which helps the hydration reaction of cement, thereby improving the strength of concrete. And pre-wetting the light waste residue particles can reduce the temperature and humidity differences inside the concrete, avoid cracks inside the concrete, and at the same time pre-wetting the light waste residue particles can reduce the air holes in the concrete, thus reducing the risk of water absorption and abrasion of the concrete and improving the durability of the concrete.

[0018] Further, when the gel material is a mixture of cement and light waste residue powder, 0.2 - 0.5 wt% of water reducer is also added to the concrete.

[0019] Note: The polar hydrophilic groups in the water reducer are adsorbed on the surface of cement particles in an oriented manner to form a stable solvated water film, which plays a three-dimensional protection role and prevents the direct contact between cement particles, thus playing a lubricating role between particles. The water reducer molecules are adsorbed on the surface of cement particles in an oriented manner, making the cement particles carry the same charge (usually negative charge), forming an electrostatic repulsion effect, dispersing the cement particles from each other, disintegrating the agglomerated structure, releasing part of the mixed water surrounded by cement particles to participate in the flow, and increasing the fluidity of the concrete. In the structure of the water reducer, the hydrophilic side chains extend into the aqueous solution to form a hydrophilic three-dimensional adsorption layer with a certain thickness on the surface of the adsorbed cement particles. When the cement particles approach, the adsorption layers begin to overlap, generating a steric hindrance effect, interfering with the agglomeration of cement particles, and thus keeping the slump of the concrete in a good state.

[0020] Furthermore, the water reducer consists of Agent I premixed with the light waste residue particles and Agent II blended with the water, where the dosage ratio of Agent I to Agent II is 20 - 45 wt% Agent I and 55 - 80 wt% Agent II;

[0021] By weight parts, Agent I is composed of 10 - 20 parts of isopentenyl alcohol polyoxyethylene ether, 5 - 10 parts of polyglutamic acid, and 10 - 15 parts of hydroxyethyl acrylate; Agent II is composed of 10 - 20 parts of sodium rosinate soap, 5 - 15 parts of sodium lignosulfonate, and 5 - 10 parts of ammonium persulfate.

[0022] Note: Using the mixture of isopentenyl alcohol polyoxyethylene ether, polyglutamic acid, and hydroxyethyl acrylate as Agent I and applying it to the mixing treatment of lightweight waste residue particles, while using sodium rosinate soap, sodium lignosulfonate, ammonium persulfate and the remaining water for co - mixing and adding it when adding water subsequently can significantly improve the compatibility with lightweight waste residue particles, can greatly improve the early or late strength of concrete, can improve the density and durability of concrete, making the concrete more solid and durable and enhancing its service life.

[0023] The present invention also provides a preparation method of lightweight waste residue high - fluidity concrete for roadbeds, comprising the following steps:

[0024] Step 1: Conduct low - temperature co - mixing treatment on Agent I and lightweight waste residue particles, then use water to pre - wet the lightweight waste residue particles, and let it stand for 10 - 15 minutes after stirring in a concrete mixer for 1 minute to obtain an aggregate mixture;

[0025] Step 2: Mix the gel material with the aggregate mixture, and during this process, add the mixed liquid obtained by mixing Agent II and the water, and fully stir to obtain lightweight waste residue high - fluidity concrete.

[0026] Note: Adopting the above - mentioned preparation method can provide a specific implementation method for the use of Agent I and Agent II of water - reducing agents, so as to reasonably use Agent I and Agent II in the preparation process of lightweight waste residue high - fluidity concrete. By pre - treating the lightweight waste residue particles with Agent I and then using Agent II for co - mixing and compounding with water, lightweight waste residue high - fluidity concrete with better performance can be obtained.

[0027] Further, the low - temperature co - mixing treatment is as follows:

[0028] Heat the lightweight waste residue particles to T 1 , spray the room - temperature Agent I onto the lightweight waste residue particles in multiple times and stir quickly. Each time the lightweight waste residue particles cool from T 1 to T 2 , then re - heat the lightweight waste residue particles to T 1 , until the room - temperature Agent I is completely sprayed; wherein, T 1 -T 2 = 15 - 25 °C, and T 1 = 50 - 60 °C.

[0029] Description: Using the above temperature difference for the pretreatment of lightweight waste residue particles can improve their activity, thereby enhancing the use effect of lightweight waste residue particles in concrete based on the components of Agent I. At the same time, through the above treatment, the hardness, wear resistance, etc. of lightweight waste residue particles can also be enhanced, enabling lightweight waste residue particles to be better utilized as concrete aggregates for resource utilization.

[0030] The beneficial effects of the present invention are as follows:

[0031] The present invention uses lightweight waste residue particles as the main component, and uses a cementitious material to be compounded with lightweight waste residue powder to prepare a high-fluidity concrete for subgrade engineering. On the one hand, it can realize the resource utilization of solid waste. On the other hand, it can prepare subgrade materials that are easy to construct, have good stability, and controllable costs, reducing potential road safety hazards, which is of great significance for China's strategy of building a transportation power and has important economic, social, and environmental benefits. Specific embodiments

[0032] The following will further elaborate on the present invention in detail in combination with specific embodiments to better reflect the advantages of the present invention.

[0033] Example 1: A high-fluidity concrete for subgrade using lightweight waste residue, comprising 54 wt% of lightweight waste residue particles, 26 wt% of a gelling material, and 20 wt% of water; the gelling material is cement.

[0034] Among them, the lightweight waste residue particles are the sludge gasification slag produced by the pyrolysis gasification of a sewage treatment plant. The cement is Portland cement with a strength grade of 42.5. The lightweight waste residue powder is obtained by grinding the sludge gasification slag in a ball mill for 30 minutes and then passing through a 500-mesh sieve. Finer mesh numbers can be selected according to actual production conditions. The particle size of the lightweight waste residue particles is 2.36 - 20 mm. Specifically, after screening out the particles with a size less than 2.36 mm, the particle gradation of the particles on the 2.36 sieve should meet the requirements of Table 1:

[0035] Table 1 Particle gradation of the mixed aggregate of sludge gasification slag with a size larger than 2.36 mm

[0036] Square sieve size (mm) 19.0 16.0 9.50 4.75 2.36 Cumulative sieve residue (%) 0～10 — 40～80 90～100 95～100

[0037] The preparation method of the above high-fluidity concrete for subgrade using lightweight waste residue includes the following steps:

[0038] Step 1: Weigh 1 kg of sun-dried sludge gasification slag to measure its water absorption, and then weigh the lightweight waste residue particles, gelling material, and water in proportion. Use water to pre-wet the lightweight waste residue particles. The water consumption for the pre-wetting treatment is 70% of the water absorption of the lightweight waste residue particles. After stirring in a concrete mixer for 1 minute, let it stand for 12 minutes to obtain an aggregate mixture;

[0039] Step 2: Prepare the gel material and mix it with the aggregate mixture. During this process, gradually add the remaining amount of water and stir well for 4 minutes to obtain lightweight waste residue high-fluidity concrete.

[0040] Example 2: The difference between this example and Example 1 is that the gel material is a mixture of cement and fly ash. Among them, the mixing ratio of cement to fly ash is 12 wt% cement and 88 wt% fly ash.

[0041] Example 3: The difference between this example and Example 2 is that the mixing ratio of cement to fly ash is 5 wt% cement and 95 wt% fly ash.

[0042] Example 4: The difference between this example and Example 2 is that the mixing ratio of cement to fly ash is 15 wt% cement and 85 wt% fly ash.

[0043] Example 5: The difference between this example and Example 1 is that the gel material is a mixture of cement and lightweight waste residue powder. Among them, the mixing ratio of cement to sludge gasification residue powder is 12 wt% cement and 88 wt% sludge gasification residue powder.

[0044] Example 6: The difference between this example and Example 5 is that the mixing ratio of cement to sludge gasification residue powder is 5 wt% cement and 95 wt% sludge gasification residue powder.

[0045] Example 7: The difference between this example and Example 5 is that the mixing ratio of cement to sludge gasification residue powder is 15 wt% cement and 85 wt% sludge gasification residue powder.

[0046] Example 8: The difference between this example and Example 5 is that when the gel material is a mixture of cement and lightweight waste residue powder, 0.4 wt% of water reducer is added to the concrete. The water reducer is the commercially available PCA-III polycarboxylate high-retention water reducer.

[0047] Example 9: The difference between this example and Example 8 is that when the gel material is a mixture of cement and lightweight waste residue powder, 0.2 wt% of water reducer is added to the concrete.

[0048] Example 10: The difference between this example and Example 8 is that when the gel material is a mixture of cement and lightweight waste residue powder, 0.5 wt% of water reducer is added to the concrete.

[0049] Calculate the dosage of each raw material according to the optimal mix ratio, stir thoroughly, mix evenly, and measure its slump, spread, pressure bleeding rate, and apparent density. Then, place the concrete mixture into the test mold for molding, cover the surface with plastic wrap, and demold the specimen after 32 hours of molding to obtain lightweight waste high-fluidity concrete test blocks. Place the demolded test blocks in a standard curing room with a temperature of 20°C ± 2°C and a relative humidity of not less than 95% and cure them to the target age. Conduct unconfined compressive strength tests, CBR tests, shear tests, and dry shrinkage tests on the test blocks cured to the age, as shown in Table 2 and Table 3:

[0050] Table 2 Mix ratio of raw materials for concrete when sludge gasification slag is used as aggregate

[0051]

[0052] Table 3 Performance indicators of concrete when sludge gasification slag is used as aggregate

[0053]

[0054]

[0055] From the above cases, it can be seen that using sludge gasification slag as aggregate can meet the performance requirements of the subgrade. Preparing the subgrade with lightweight waste high-fluidity concrete can not only reduce the use of earthwork but also improve the performance of the subgrade, achieving the problem of the disposal of low-strength lightweight waste solid waste.

[0056] Example 11: The difference between this example and Example 1 is that the lightweight waste high-fluidity concrete for subgrade includes 51 wt% lightweight waste particles, 24 wt% gel material, and 25 wt% water.

[0057] Example 12: The difference between this example and Example 1 is that the lightweight waste high-fluidity concrete for subgrade includes 56 wt% lightweight waste particles, 28 wt% gel material, and 16 wt% water.

[0058] Example 13: The difference between this example and Example 1 is that the water consumption for the pre-wetting treatment is 50% of the water absorption of the lightweight waste particles. After stirring in a concrete mixer for 1 minute and then standing for 10 minutes, an aggregate mixture is obtained.

[0059] Example 14: The difference between this example and Example 1 is that the water consumption for the pre-wetting treatment is 80% of the water absorption of the lightweight waste particles. After stirring in a concrete mixer for 1 minute and then standing for 15 minutes, an aggregate mixture is obtained.

[0060] Example 15: The difference between this example and Example 1 is that the water reducing agent consists of Agent I premixed with the light waste residue particles and Agent II blended with the water. Among them, the dosage ratio of Agent I to Agent II is 40 wt% Agent I and 60 wt% Agent II. By weight, Agent I consists of 18 parts of isopentenyl polyoxyethylene ether, 7 parts of polyglutamic acid, and 12 parts of hydroxyethyl acrylate; Agent II consists of 15 parts of sodium rosinate soap, 13 parts of sodium lignosulfonate, and 9 parts of ammonium persulfate.

[0061] The preparation method of the above-mentioned light waste residue high-fluidity concrete for subgrade includes the following steps:

[0062] Step 1: Conduct a low-temperature blending treatment on Agent I and the light waste residue particles. Specifically, heat the light waste residue particles to T 1 , spray the normal-temperature Agent I onto the light waste residue particles in multiple batches and stir rapidly. After cooling from T 1 to T 2 , reheat the light waste residue particles to T 1 until the spraying of the normal-temperature Agent I is complete; then use water to conduct a pre-wetting treatment on the light waste residue particles. The water consumption for the pre-wetting treatment is 70% of the water absorption of the light waste residue particles. After stirring in a concrete mixer for 1 minute and standing for 12 minutes, an aggregate mixture is obtained;

[0063] Among them, T 1 - T 2 = 20 °C, and T 1 is 55 °C, T 2 is 35 °C;

[0064] Step 2: Prepare and group the gel materials and mix them with the aggregate mixture. During this process, add the mixed liquid obtained by mixing Agent II and the water, and stir well to obtain the light waste residue high-fluidity concrete.

[0065] Example 16: The difference between this example and Example 15 is that the water reducing agent consists of Agent I premixed with the light waste residue particles and Agent II blended with the water. Among them, the dosage ratio of Agent I to Agent II is 20 wt% Agent I and 80 wt% Agent II. By weight, Agent I consists of 10 parts of isopentenyl polyoxyethylene ether, 5 parts of polyglutamic acid, and 10 parts of hydroxyethyl acrylate; Agent II consists of 10 parts of sodium rosinate soap, 5 parts of sodium lignosulfonate, and 5 parts of ammonium persulfate.

[0066] Example 17: The difference between this example and Example 15 is that the water reducing agent consists of Agent I premixed with the light waste residue particles and Agent II blended with the water. Among them, the dosage ratio of Agent I to Agent II is 45 wt% of Agent I and 55 wt% of Agent II. By weight, Agent I consists of 20 parts of isopentenyl polyoxyethylene ether, 10 parts of polyglutamic acid, and 15 parts of hydroxyethyl acrylate; Agent II consists of 20 parts of sodium rosinate soap, 15 parts of sodium lignosulfonate, and 10 parts of ammonium persulfate.

[0067] Example 18: The difference between this example and Example 15 is that T 1 is 50 °C, and T 2 is 25 °C.

[0068] Example 19: The difference between this example and Example 15 is that T 1 is 60 °C, and T 2 is 45 °C.

[0069] Prepare concrete according to the above method, and measure its slump, spread, pressure bleeding rate, and apparent density. Then, put the concrete mixture into a test mold for molding, and cover the surface with plastic wrap. Demold the specimen 32 h after molding to obtain a light waste residue high-fluidity concrete test block. Place the demolded test block in a standard curing room at a temperature of 20 °C ± 2 °C and a relative humidity of not less than 95% until the target age. Conduct unconfined compressive strength tests, CBR tests, shear tests, and dry shrinkage tests on the test blocks cured to the age, as shown in Table 4:

[0070] Table 4 Performance indicators of concrete under different water reducing agents

[0071]

[0072]

[0073] As can be seen from the above cases, L1 to L5 correspond to Examples 15 to 19 respectively. After using the water reducing agent of Agent I and Agent II, the performance indicators such as the compressive strength of the concrete have been significantly improved. For example, taking L1 as an example, after using this water reducing agent, the 28-day unconfined compressive strength has increased from 0.99 MPa to 1.23 MPa. Therefore, the use of this water reducing agent can further improve the service performance of the roadbed and achieve the problem of the disposal of low-strength light waste residue solid waste.

[0074] Example 20: The difference between this example and Example 1 is that the light waste residue particles are biomass ash produced by a biomass power plant.

[0075] Calculate the dosage of each raw material according to the optimal mix ratio, stir thoroughly, mix evenly, and measure its slump, spread, pressure bleeding rate, and apparent density. Then, put the concrete mixture into the test mold for molding, cover the surface with plastic wrap, and demold the specimen after 32 h of molding to obtain the lightweight waste residue high-fluidity concrete test block. Place the demolded test block in a standard curing room with a temperature of 20°C ± 2°C and a relative humidity of not less than 95% and cure it to the target age. Conduct unconfined compressive strength tests, CBR tests, shear tests, and dry shrinkage tests on the test blocks cured to the age, as shown in Table 5 and Table 6:

[0076] Table 5 Raw material mix ratio of concrete when biomass power plant ash slag is used as aggregate

[0077]

[0078] Table 6 Performance indicators of concrete when biomass power plant ash slag is used as aggregate

[0079]

[0080]

[0081] As can be seen from the above cases, using biomass power plant ash slag as aggregate can meet the performance requirements of the roadbed. Preparing the roadbed with lightweight waste residue high-fluidity concrete can not only reduce the use of earthwork but also improve the performance of the roadbed, achieving the problem of the disposal of low-strength lightweight waste residue solid waste.

[0082] Example 21: The difference between this example and Example 1 is that the lightweight waste residue particles are fluidized bed ash slag produced by a thermal power plant.

[0083] Calculate the dosage of each raw material according to the optimal mix ratio, stir thoroughly, mix evenly, and measure its slump, spread, pressure bleeding rate, and apparent density. Then, put the concrete mixture into the test mold for molding, cover the surface with plastic wrap, and demold the specimen after 32 h of molding to obtain the lightweight waste residue high-fluidity concrete test block. Place the demolded test block in a standard curing room with a temperature of 20°C ± 2°C and a relative humidity of not less than 95% and cure it to the target age. Conduct unconfined compressive strength tests, CBR tests, shear tests, and dry shrinkage tests on the test blocks cured to the age, as shown in Table 7 and Table 8:

[0084] Table 7 Raw material mix ratio of concrete when biomass power plant ash slag is used as aggregate

[0085]

[0086] Table 8 Performance indicators of concrete when biomass power plant ash slag is used as aggregate

[0087]

[0088] As can be seen from the above cases, the ash and slag of biomass power plants can meet the performance requirements of subgrades as aggregates. Using lightweight waste high-fluidity concrete to prepare subgrades can not only reduce the use of earthwork, but also improve the performance of subgrades, achieving the problem of disposal of low-strength lightweight waste solid waste.

Claims

1. A lightweight waste slag high-flow concrete for roadbed, characterized in that: The invention comprises 51-56 wt% of light waste slag particles, 24-28 wt% of gel material and 16-25 wt% of water; the gel material is cement, or a mixture of cement and any one of fly ash and light waste slag powder.

2. The lightweight waste slag high-flow concrete for roadbed as claimed in claim 1, characterized in that: The light waste residue particles are one of sludge gasification residue produced by pyrolysis and gasification of a sewage treatment plant, biomass ash produced by a biomass power plant, or fluidized bed ash produced by a thermal power plant. The particle size of the light waste residue particles is 2.36 to 20 mm.

3. The lightweight waste slag high-flow concrete for roadbed as claimed in claim 1, characterized in that: The light waste residue powder is obtained by grinding any one of sludge gasification residue produced by pyrolysis and gasification of a sewage treatment plant, biomass ash residue produced by a biomass power plant, or fluidized bed ash residue produced by a thermal power plant through a ball mill and passing through a 500-600 mesh sieve.

4. The lightweight waste slag high-flow concrete for roadbed as claimed in claim 1, characterized in that: In the gel material, the mixing ratio of cement to fly ash is 5-15wt% cement and 85-95wt% fly ash; the mixing ratio of cement to light waste slag powder is 5-15wt% cement and 85-95wt% light waste slag powder.

5. The lightweight waste slag high-flow concrete for roadbed as claimed in claim 1, characterized in that: The cement is silicate cement with a strength grade of 42.5, and the particle size of the light waste slag particles is 2.36-20 mm.

6. The lightweight waste slag high-flow concrete for roadbed as claimed in claim 1, characterized in that: The light waste residue particles need to be pre-wetted with water, and the amount of water used in the pre-wetted water treatment is 50-80% of the water absorption of the light waste residue particles.

7. The lightweight waste slag high-flow concrete for roadbed as claimed in claim 1, characterized in that: When the gel material is a mixture of cement and light waste slag powder, a water reducing agent accounting for 0.2-0.5wt% of the total weight of the concrete is also added to the concrete.

8. The lightweight waste slag high-flow concrete for roadbed as claimed in claim 7, characterized in that: The water reducing agent is composed of an agent I premixed with the light waste slag particles and an agent II mixed with the water, wherein the dosage ratio of agent I to agent II is 20-45wt% agent I and 55-80wt% agent II; In terms of weight, agent I is composed of 10 to 20 parts of isopentanol polyoxyethylene ether, 5 to 10 parts of polyglutamic acid, and 10 to 15 parts of hydroxyethyl acrylate; agent II is composed of 10 to 20 parts of rosin sodium soap, 5 to 15 parts of sodium lignin sulfonate, and 5 to 10 parts of ammonium persulfate.

9. The method for preparing a lightweight waste slag high-flow concrete for roadbed according to claim 8, characterized in that: The following steps are involved: Step 1, subjecting Agent I and lightweight waste slag particles to low-temperature blending treatment, then pre-wetting the lightweight waste slag particles with water, stirring in a concrete mixer for 1 minute and then standing for 10 to 15 minutes to obtain an aggregate mixture; Step 2: Mix the gel material with the aggregate mixture, add the mixture obtained by mixing Agent II with the water, and stir thoroughly to obtain lightweight waste slag high-flow concrete.

10. The method for preparing lightweight waste slag high-flow concrete for roadbed according to claim 9, characterized in that: The low temperature blending process is: The light waste slag particles are heated to T1, and the room temperature Agent I is sprayed onto the light waste slag particles in multiple times and quickly stirred. Each time the light waste slag particles are cooled from T1 to T2, the light waste slag particles are warmed up to T1 until the room temperature Agent I is completely sprayed; wherein, T1-T2=15-25°C, and T1=50-60°C.

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