A low-clinker cement fine-grained steel slag crushed stone pavement base material

Abstract

This invention relates to the field of road materials technology, specifically to a low-clinker cement fine-grained steel slag crushed stone pavement base material, comprising the following components by mass percentage: 50.0%-100.0% phosphorus-containing fine-grained steel slag, 0%-50.0% crushed stone, 2.0%-5.0% low-clinker cement (based on the sum of the mass of phosphorus-containing fine-grained steel slag and crushed stone), and 5.0%-9.0% water (based on the sum of the mass of phosphorus-containing fine-grained steel slag, crushed stone, and low-clinker cement). By using phosphorus-containing fine-grained steel slag as raw material, combined with low-clinker cement and crushed stone, a high-performance, low-cost highway pavement base material is prepared, significantly improving the comprehensive utilization rate of steel slag. The low-clinker cement fine-grained steel slag crushed stone pavement base material provided by this invention has the advantages of excellent road performance, good water stability, and significant late-stage strength growth. Its 28-day compressive strength can increase by 30%-50% compared to its 7-day compressive strength, ensuring the long-term stable operation of the pavement base.

Description

Technical Field

[0001] This invention relates to the field of road materials technology, specifically to a low-clinker cement fine-grained steel slag crushed stone pavement base material. Background Technology

[0002] With the rapid development of my country's transportation infrastructure construction, higher requirements have been placed on the performance, cost, and environmental friendliness of road base materials. Traditional cement-stabilized crushed stone base materials use ordinary Portland cement with a high clinker content (usually between 80% and 95%), and crushed stone and manufactured sand are used as aggregates.

[0003] In recent years, researchers have attempted to replace natural aggregates with steel slag in road base courses. However, existing steel slag water-stabilized base course materials contain a large amount of large-diameter steel slag (>10mm). These large-diameter particles have complex physical properties and poor volume stability. Long-term aging only dissipates the free calcium oxide (f-CaO) on the surface; the internal free calcium oxide (f-CaO) is difficult to remove. Under high temperatures and rainfall, this easily causes pavement damage. This problem results in the low utilization rate of steel slag in road base courses, making large-scale utilization of steel slag difficult.

[0004] Therefore, how to achieve the large-scale application of steel slag in road base materials while reducing the construction cost of road base materials, reducing carbon emissions and sand and gravel resource consumption, and constructing high-performance green and low-carbon road base materials with solid waste materials as the main raw materials has become an urgent problem to be solved in the field of road engineering. Summary of the Invention

[0005] One of the objectives of this invention is to provide a low-clinker cement fine-grained steel slag crushed stone pavement base material to address the problems existing in the prior art. By using phosphorus-containing fine-grained steel slag as raw material, combined with low-clinker cement and crushed stone, a high-performance and low-cost highway pavement base material is prepared, and the comprehensive utilization rate of steel slag is significantly improved.

[0006] The second objective of this invention is to provide a method for preparing a low-clinker cement fine-grained steel slag crushed stone pavement base material, thereby realizing the large-scale utilization of steel slag.

[0007] The first aspect of this invention discloses the following technical solution: a low-clinker cement fine-grained steel slag crushed stone pavement base material, comprising the following components by mass percentage: 50.0%-100.0% phosphorus-containing fine-grained steel slag, 0%-50.0% crushed stone, 2.0%-5.0% low-clinker cement based on the sum of the mass of phosphorus-containing fine-grained steel slag and crushed stone, and 5.0%-9.0% water based on the sum of the mass of phosphorus-containing fine-grained steel slag, crushed stone, and low-clinker cement.

[0008] Furthermore, the phosphorus-containing fine steel slag is prepared by mixing fine steel slag and modified microporous zeolite in a mass ratio of 3:1, followed by crushing, sieving, water saturation aging, and stirring.

[0009] Furthermore, the low-clinker cement is composed of the following components by mass percentage: 45.0%-55.0% cement clinker, 35.0%-40.0% slag-steel slag binary composite powder, 3.0%-5.0% limestone powder, 3.0%-4.0% desulfurized gypsum, 1.5%-3.0% slag, and 0.06%-0.12% acetic acid-modified triethanolamine. The 28-day compressive strength of the low-clinker cement is not less than 32.5 MPa.

[0010] Furthermore, the mass ratio of slag to steel slag in the slag-steel slag binary composite powder is 8:2, and the particle size is 1-100μm.

[0011] Furthermore, the acetic acid-modified triethanolamine is prepared by esterification reaction of triethanolamine and anhydrous acetic acid mixed in a mass ratio of 2.5:1.

[0012] Furthermore, the nominal particle size of the phosphorus-containing fine steel slag is controlled below 10 mm, and the passing rate of the 4.75 mm square hole sieve is not less than 90%, and the particle size of the crushed stone is 10-30 mm.

[0013] Furthermore, the phosphorus-containing fine-grained steel slag has a water immersion expansion rate of ≤1.0% and an apparent density of 3200~3400 kg / m³.

[0014] The second aspect of this invention discloses a method for preparing a low-clinker cement fine-grained steel slag crushed stone pavement base material, comprising the following steps:

[0015] S01. Preparation of phosphorus-containing fine-grained steel slag

[0016] Steel slag with a particle size of less than 10 mm was selected and mixed with modified microporous zeolite in a 3:1 ratio to obtain a steel slag zeolite mixture. The steel slag zeolite mixture was piled up and a portion was reserved for use. A steel slag zeolite mixture pile with a concave center was constructed, and aquaculture wastewater was injected into it. Magnetized water was sprayed on the outside, and the steel slag zeolite mixture pile was aged under water-saturated conditions for 1-1.5 months.

[0017] After the ammonia nitrogen removal rate in the aquaculture wastewater exceeds 70% or the phosphate removal rate exceeds 80%, the steel slag zeolite mixture is removed, and fine steel slag particles with a particle size range of less than 4.75 mm are filtered and screened out. The remaining mixture with a particle size range greater than 4.75 mm is thoroughly stirred, mixed, and crushed with the retained steel slag zeolite mixture to obtain a crushed mixture. The fine steel slag particles with a particle size range of less than 4.75 mm are then mixed with the crushed mixture a second time at a mass fraction ratio of 5:1 to obtain phosphorus-containing fine steel slag. The phosphorus-containing fine steel slag has a passing rate of not less than 90% through a 4.75 mm square hole sieve.

[0018] S02, Preparation of low-clinker cement

[0019] Cement clinker is coarsely crushed to a particle size of ≤25mm using a jaw crusher, and then medium crushed to ≤5mm using a cone crusher to ensure subsequent grinding efficiency.

[0020] Pretreated cement clinker, slag-steel slag binary composite powder, limestone powder, desulfurized gypsum, and slag are put into the mill in proportion. During the grinding process, acetic acid-modified triethanolamine solution is sprayed into the mill through the nozzle. The mixture after grinding is classified by the built-in air classifier. Coarse particles are returned to the grinding disc for further grinding, and qualified fine powder is collected by the dust collector to obtain low clinker cement.

[0021] S03, Preparation of low-clinker cement fine-grained steel slag and crushed stone mixture

[0022] Weigh out the phosphorus-containing fine-grained steel slag, crushed stone, a small amount of clinker cement, and water according to the maximum dry density;

[0023] Weigh out all the raw materials and put them into a forced mixer. Add water according to the optimum moisture content and mix for 2 minutes to make a low clinker cement fine-grained steel slag crushed stone mixture.

[0024] The mixture is compacted and cured under standard curing conditions of 20℃±2℃ and ≥95% humidity until the corresponding age.

[0025] Furthermore, the magnetized water is obtained by passing ordinary water through a magnetic field with a magnetic induction intensity of 2000Gs~3000Gs, controlling the water flow speed at 0.6m / s±10%, and allowing the water body to undergo a 30-minute cycle of magnetization treatment along a direction perpendicular to the magnetic field lines.

[0026] The advantages of this invention are:

[0027] (1) The present invention provides a low-clinker cement-stabilized fine-grained steel slag crushed stone pavement base material, which mainly consists of steel slag, crushed stone, and low-clinker cement. Compared with traditional cement-stabilized crushed stone, it can save the construction cost of pavement base materials for urban roads and highways in steel slag producing areas. Under the same cement dosage, it can reduce the carbon dioxide emissions of the pavement base material by about 50%, which has significant green and low-carbon benefits and economic benefits. The low-clinker cement-stabilized fine-grained steel slag crushed stone pavement base material provided by the present invention has the advantages of excellent road performance, good water stability, and significant later strength growth. Its 28-day compressive strength can increase by 30% to 50% compared with the 7-day compressive strength, which can ensure the long-term stable operation of the pavement base material. In addition, compared with traditional cement-stabilized crushed stone, under the same performance, the low-clinker cement-stabilized fine-grained steel slag crushed stone requires less cement and crushed stone, further saving costs.

[0028] (2) This invention provides a method for preparing cement-stabilized pavement base material using fine-grained steel slag as raw material. The fine-grained steel slag is treated by means of particle size control and water saturation aging, which can solve the problem of pavement damage caused by steel slag expansion in traditional steel slag pavement base materials using large-particle steel slag. It is conducive to the large-scale utilization of steel slag and has great prospects for promotion and application. Among them, the fine-grained steel slag is water saturated and aged by aquaculture wastewater and magnetized water. As a water treatment agent, steel slag can play a role in adsorption and precipitation in wastewater treatment. The fine-grained steel slag adsorbs and dissolves phosphorus in aquaculture wastewater, which is not only economical, but also conforms to the principle of treating waste with waste, with significant green and low-carbon benefits and broad application prospects. After being subjected to a magnetic field, the water molecule cluster structure of the magnetized water is destroyed, forming smaller water molecule clusters, and the permeability and activity are significantly enhanced. This makes it easier for water molecules to penetrate into the pores inside the steel slag, which can accelerate the decomposition of free calcium oxide (f-CaO) and free magnesium oxide (f-MgO) in the steel slag. Under the same conditions, magnetized water can reduce the aging time by about 30 to 40% compared with ordinary water.

[0029] (3) The low-clinker cement provided by this invention incorporates slag and acetic acid-modified triethanolamine. During the cement hydration reaction, the active SiO2 and Al2O3 in the slag can consume the unstable Ca(OH)2 crystals in the cement stone, promote the formation of chemically stable hydrated calcium silicate and hydrated calcium aluminate, and improve the density of the hardened cement. The slag particle size can optimize the cement particle size distribution. At the same time, the glass phase in the slag has water retention properties, which can reduce the unit water consumption of concrete, lower the water-cement ratio, and improve the density of the hardened cement. The slag can inhibit the alkali-aggregate reaction. The slag has a positive effect on the alkali ions (Na+) in the cement system. + K + It has stronger binding capacity, which can reduce the probability of alkali-aggregate reaction and improve durability. Acetic acid-modified triethanolamine can improve the fineness of cement. Compared with conventional triethanolamine, the use of acetic acid-modified triethanolamine can reduce the cement sieve residue by about 8.0%; it also improves the mechanical properties of cement, with early strength increasing by 12%~15% and later strength increasing by 8%~10%. Attached Figure Description

[0030] Figure 1 This is a microscopic image of the interface between hardened cement stone and steel slag in low-clinker cement-stabilized fine-grained steel slag crushed stone.

[0031] Figure 2 It is a microscopic image of the interface between hardened cement stone and crushed stone in cement-stabilized crushed stone. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples and comparative examples are only used to more clearly illustrate the technical solutions of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention, and are not intended to limit the scope of protection of the present invention.

[0033] The test methods, production processes, instruments, and equipment involved in the embodiments and comparative examples of this invention are all conventional names in the art, and are very clear and distinct in the relevant application fields. Those skilled in the art can understand the conventional process steps and apply the corresponding equipment based on the names, and implement them according to conventional conditions or conditions recommended by the manufacturer.

[0034] The raw materials or reagents used in the embodiments and comparative examples of this invention are not subject to any special restrictions on their source and are all conventional products that can be purchased commercially.

[0035] The following specific embodiments will illustrate the above-mentioned low-clinker cement fine-grained steel slag crushed stone pavement base material and its application performance according to the present invention. However, those skilled in the art will understand that the content of the present invention described below is not limited to the following embodiments. These embodiments are provided to explain the principles of the present invention and its practical application, thereby enabling other those skilled in the art to understand the various embodiments of the present invention and various modifications suitable for specific intended applications.

[0036] In the following embodiments, the unconfined compressive strength, splitting strength, shrinkage characteristics, and water immersion swelling rate of the low clinker cement fine-grained steel slag crushed stone pavement base materials and comparative pavement base materials prepared in the following embodiments were tested according to the methods described in "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (JTG 3441-2024) and "Steel Slag for Road Use" (GB / T 25824-2010).

[0037] Example 1: Preparation of fine-grained steel slag crushed stone pavement base material with low clinker cement

[0038] 1) Preparation of phosphorus-containing fine-grained steel slag.

[0039] Steel slag with a particle size of less than 10 mm was mixed with modified microporous zeolite in a 3:1 ratio to obtain a steel slag-zeolite mixture. 50% of the steel slag-zeolite mixture was piled up and the other 50% was reserved for use. A steel slag-zeolite mixture pile with a concave center was constructed, and aquaculture wastewater was injected into it. Magnetized water was sprayed on the outside, and the steel slag-zeolite mixture pile was aged under saturated water conditions for 1-1.5 months.

[0040] The ammonia nitrogen and phosphate contents in the wastewater to be used for aquaculture were detected using an ammonia nitrogen analyzer and a spectrophotometer. The calculated ammonia nitrogen removal rate was 83%, and the phosphate removal rate was 95%, meeting the preparation standards. The steel slag-zeolite mixture was removed, filtered, and sieved to separate fine steel slag particles with a particle size range of less than 4.75 mm. The remaining mixture with a particle size range greater than 4.75 mm was thoroughly stirred, mixed, and crushed with the reserved steel slag-zeolite mixture to obtain a crushed mixture. The fine steel slag particles smaller than 4.75 mm were then mixed a second time with the crushed mixture at a mass ratio of 5:1 to obtain phosphorus-containing fine steel slag. The phosphorus-containing fine steel slag had a passing rate of no less than 90% through a 4.75 mm square-hole sieve.

[0041] 2) Preparation of low-clinker cement.

[0042] Cement clinker is coarsely crushed to a particle size of ≤25mm using a jaw crusher, and then medium crushed to ≤5mm using a cone crusher to ensure subsequent grinding efficiency.

[0043] Pretreated cement clinker, slag-steel slag binary composite powder, limestone powder, desulfurized gypsum, and slag are put into the mill in proportion. During the grinding process, acetic acid-modified triethanolamine solution is sprayed into the mill through nozzles. The mixture after grinding is classified by the built-in air classifier. Coarse particles are returned to the grinding disc for further grinding, while qualified fine powder is collected by the dust collector to obtain low-clinker cement.

[0044] 3) Sample preparation of fine-grained steel slag crushed stone pavement base material with low clinker cement.

[0045] Weigh out the phosphorus-containing fine-grained steel slag, crushed stone, and low-clinker cement according to the maximum dry density;

[0046] Weigh out all the raw materials and put them into a forced mixer. Add water according to the optimum moisture content and mix for 2 minutes to make a low clinker cement stabilized fine-grained steel slag crushed stone mixture.

[0047] The mixture is poured into a test mold and compacted to form the final product;

[0048] After demolding, the specimens were placed in plastic bags, sealed, and placed in a curing room. They were then cured under standard curing conditions of 20℃±2℃ and ≥95% humidity until the corresponding age.

[0049] Example 2: Comparison of test parameters for steel slag with different contents

[0050] Experimental groups numbered 1-6 were set up according to different steel slag ratios. The steel slag content of each group increased sequentially, and the crushed stone content of each group decreased sequentially according to the steel slag ratio. Detailed parameters are shown in Table 1.

[0051]

[0052] 1) Compaction test.

[0053] According to the "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering" (JTG 3441-2024) T0804-1994, compaction test was conducted on inorganic binder stabilized materials. The optimal moisture content and maximum dry density parameters of experimental groups 1-6 are shown in Table 2 below.

[0054]

[0055] 2) Unconfined compressive strength and splitting strength tests.

[0056] According to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (JTG 3441-2024) and "Steel Slag for Road Use" (GB / T 25824-2010), the base course materials of fine-grained steel slag crushed stone pavement with low clinker cement in experimental groups 1-6 were tested. The test results of unconfined compressive strength, splitting strength, shrinkage characteristics and water immersion swelling rate are shown in Table 3.

[0057]

[0058] As shown in Table 3, the mechanical properties of low-clinker cement-stabilized fine-grained steel slag crushed stone first increase and then decrease with increasing phosphorus-containing fine-grained steel slag content, reaching their optimal level when the phosphorus-containing fine-grained steel slag content reaches 60%~70%. Furthermore, the water immersion swelling rate of the low-clinker cement-stabilized fine-grained steel slag crushed stone with the above-mentioned proportions all meet the requirement of ≤2.0% specified in "Steel Slag for Road Use" (GB / T25824-2010).

[0059] Example 3: Comparison of test parameters for cement with different clinker contents

[0060] Experimental groups numbered 7-9 were set up according to different proportions of low clinker cement, with the low clinker cement content of each group increasing sequentially. Detailed parameters are shown in Table 4.

[0061]

[0062] 1) Compaction test.

[0063] According to the "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering" (JTG 3441-2024) T0804-1994, compaction tests were conducted on inorganic binder stabilized materials. The optimal moisture content and maximum dry density parameters of experimental groups 7-9 are shown in Table 5 below.

[0064]

[0065] 2) Unconfined compressive strength and splitting strength tests.

[0066] According to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (JTG 3441-2024) and "Steel Slag for Road Use" (GB / T 25824-2010), the base course materials of low clinker cement fine-grained steel slag crushed stone pavement with experimental group numbers 7-9 were tested. The test results of unconfined compressive strength, splitting strength, shrinkage characteristics and water immersion swelling rate are shown in Table 6.

[0067]

[0068] As shown in Table 6, the lower the clinker cement content, the lower the mechanical properties and the smaller the shrinkage deformation of the clinker cement-stabilized fine-grained steel slag crushed stone. When the cement admixture is reduced to 3% and 4%, the clinker cement-stabilized fine-grained steel slag crushed stone can still meet the highest standard requirement of not less than 5.0 MPa for the unconfined compressive strength of the pavement base course at 7 days as specified in the "Technical Specifications for Construction of Highway Pavement Base Course" (JTG+T+F20-2015); while when the cement admixture is reduced to 2%, it can still meet the highest standard requirement of not less than 4.0 MPa for the unconfined compressive strength of the pavement subbase course at 7 days.

[0069] Example 4: Comparison Test with Existing Base Materials

[0070] 1) Selection of existing basic materials.

[0071] Control groups 10-12 were prepared according to conventional experimental methods, and the dosages of control groups 10-12 were set up with reference to the dosages in Example 1. The dosage ratios of each component were calculated as shown in Tables 7-9, where:

[0072] Number 10 is the control group of traditional cement stabilized crushed stone, which uses ordinary Portland cement, manufactured sand and crushed stone;

[0073]

[0074] Number 11 is the control group for traditional cement-stabilized steel slag, which uses ordinary silicate cement and coarse-grained steel slag (conventional aging reaction).

[0075]

[0076] Number 12 is the control group of ordinary low-clinker cement and fine-grained steel slag, which uses ordinary low-clinker cement and fine-grained steel slag (conventional aging reaction).

[0077]

[0078] 2) Compaction test.

[0079] According to the "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering" (JTG 3441-2024) T0804-1994, compaction test was conducted on inorganic binder stabilized materials. The optimum moisture content and maximum dry density parameters of the control group 10-12 are shown in Table 10 below.

[0080]

[0081] 3) Unconfined compressive strength and splitting strength tests.

[0082] According to the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (JTG 3441-2024) and "Steel Slag for Road Use" (GB / T 25824-2010), the pavement base material of control group 10-12 was tested. The test results of unconfined compressive strength, splitting strength, shrinkage characteristics and water immersion swelling rate are shown in Table 11.

[0083]

[0084] As can be seen from the embodiments described in this application, the phosphorus-containing fine-grained steel slag crushed stone with low clinker cement exhibits superior compressive strength and splitting strength compared to ordinary low-clinker cement fine-grained steel slag, traditional cement-stabilized steel slag, and traditional cement-stabilized crushed stone. Regarding the water immersion expansion rate, traditional cement-stabilized crushed stone, lacking the presence of steel slag, demonstrates the best performance, while traditional cement-stabilized steel slag exhibits the worst performance. Compared to ordinary low-clinker cement fine-grained steel slag crushed stone, the phosphorus-containing fine-grained steel slag crushed stone with low clinker cement shows a significantly enhanced water immersion expansion rate. Furthermore, the water immersion expansion rates of different phosphorus-containing steel slag and crushed stone components all meet the requirement of ≤2.0% as specified in the "Road Steel Slag" standard (GB / T25824-2010).

[0085] Compared to ordinary low-clinker cement with fine-grained steel slag, low-clinker cement with fine-grained steel slag crushed stone exhibits superior mechanical properties, more significant later-stage strength growth, lower water immersion swelling rate, and better volume stability. Furthermore, the addition of phosphorus-containing fine-grained steel slag allows for the achievement of the same or even better mechanical properties with a lower cement dosage. In summary, phosphorus-containing low-clinker cement stabilized fine-grained steel slag crushed stone not only makes extensive use of steel slag and restores phosphorus-containing wastewater, but also achieves excellent mechanical properties, good stability, and less shrinkage deformation, all at a lower cost, significantly reducing the construction cost of highway pavement base courses.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cement fine granular steel slag macadam pavement base material with less clinker, characterized by, The cement comprises the following components in percentage by mass: 50.0%-100.0% of the phosphorus-containing fine steel slag, 0%-50.0% of the gravel, 2.0%-5.0% of the low-clinker cement, and 5.0%-9.0% of water; The phosphorus-containing fine steel slag is prepared by mixing fine steel slag and modified microporous zeolite at a mass ratio of 3:1, crushing and sieving, saturating and aging in aquaculture wastewater and magnetized water, and stirring. The low-clinker cement is composed of the following components in percentage by mass: 45.0%-55.0% of cement clinker, 35.0%-40.0% of the slag-steel slag binary compound powder, 3.0%-5.0% of limestone powder, 3.0%-4.0% of desulfurization gypsum, 1.5%-3.0% of slag, and 0.06%-0.12% of acetic acid modified triethanolamine, and the 28d compressive strength of the low-clinker cement is not less than 32.5MPa. The acetic acid modified triethanolamine is prepared by mixing triethanolamine and anhydrous acetic acid at a mass ratio of 2.5:1 and then performing esterification reaction.

2. The cementite-few cement fine granular steel slag macadam pavement base material according to claim 1, characterized by, The mass ratio of slag to steel slag in the slag-steel slag binary compound powder is 8:2, and the particle size is 1-100μm.

3. The cementite-few cement fine granular steel slag macadam pavement base material according to claim 1, characterized by, The nominal particle size of the phosphorus-containing fine steel slag is controlled to be less than 10mm, and the passing rate of the 4.75mm square hole sieve is not less than 90%, and the particle size of the gravel is 10-30mm.

4. The cementite-few cement fine granular steel slag macadam pavement base material according to claim 1, characterized by, The water immersion expansion rate of the phosphorus-containing fine steel slag is ≤1.0%, and the apparent density is 3200-3400kg / m³.

5. A method of producing the little clinker cement fine granular steel slag macadam pavement base material according to any one of claims 1 to 4, characterized by, The method comprises the following steps: S01, preparation of the phosphorus-containing fine steel slag; The steel slag with a particle size less than 10mm is mixed with modified microporous zeolite at a mass ratio of 3:1 to obtain a steel slag-zeolite mixture; the steel slag-zeolite mixture is stored in bulk, and a part of the mixture is reserved to build a steel slag-zeolite mixture pile with an intermediate recess; aquaculture wastewater is injected into the pile, and magnetized water is sprayed outside the pile to age the steel slag-zeolite mixture under saturated water conditions for 1-1.5months; After the ammonia nitrogen removal rate of the aquaculture wastewater is higher than 70% or the phosphate removal rate is higher than 80%, the steel slag-zeolite mixture is taken out, and fine steel slag with a particle size less than 4.75mm is separated by filtering and sieving; the remaining mixture with a particle size greater than 4.75mm and the reserved steel slag-zeolite mixture are fully stirred, mixed and crushed to obtain a crushed mixture; the fine steel slag with a particle size less than 4.75mm and the crushed mixture are mixed again at a mass ratio of 5:1 to obtain the phosphorus-containing fine steel slag; the passing rate of the 4.75mm square hole sieve of the phosphorus-containing fine steel slag is not less than 90%; S02, preparation of the low-clinker cement The cement clinker is coarsely crushed to a particle size of ≤25mm by a jaw crusher, and then is medium crushed to ≤5mm by a cone crusher to ensure the subsequent grinding efficiency; The pretreated cement clinker, slag-steel slag binary compound powder, limestone powder, desulfurization gypsum and slag are put into a mill in proportion, and acetic acid modified triethanolamine solution is sprayed into the mill through a nozzle during the grinding process; the mixture after grinding is classified by an internal classifier, the coarse particles are returned to the millstone for regrinding, and the qualified fine powder is collected by a dust collector to obtain the low-clinker cement. S03, Preparation of fine-grained steel slag and macadam mixture with less cement clinker According to the maximum dry density, the fine-grained steel slag containing phosphorus, macadam, less cement clinker and water are weighed; The weighed raw materials are put into a forced mixer, water is added according to the optimum water content, and stirring is carried out for 2 min to prepare the fine-grained steel slag and macadam mixture with less cement clinker; The mixture is compacted and formed, and is cured under standard curing conditions of temperature 20℃±2℃ and humidity ≥95% to the corresponding age.

6. The method of claim 5, wherein, The magnetized water is obtained by making ordinary water flow through a magnetic field with a magnetic induction intensity of 2000Gs-3000Gs, controlling the water flow speed to be 0.6m / s±10%, and making the water body complete 30min of cyclic magnetization treatment in the vertical direction of the magnetic force line.

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