Preparation method of oil shale-based aggregate ultra-high performance concrete material

Abstract

The application discloses a preparation method of oil shale-based aggregate ultra-high performance concrete material, and comprises the following steps: (1) uniformly mixing oil shale slag, glass powder, lithium slag powder and magnesium oxide, and then performing sintering treatment, cooling to room temperature after completion, crushing the sintering product, and obtaining oil shale-based fine aggregate; (2) taking the following raw materials: composite cementitious material, the oil shale-based fine aggregate, fly ash, silica fume, modified phosphogypsum powder, fiber, water reducing agent, sodium hydroxide and / or potassium hydroxide; the composite cementitious material is composed of Portland cement and mineral powder; uniformly mixing the above raw materials, adding mixing water and uniformly stirring, and obtaining the concrete material. The method disclosed by the application not only overcomes the problem of the decrease of the strength and impermeability of the ultra-high performance concrete material prepared by using oil shale slag as fine aggregate, but also relieves the problem of the waste of cement components in the ultra-high performance concrete material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultra-high performance concrete preparation, and particularly relates to a preparation method of oil shale-based aggregate ultra-high performance concrete material. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing an understanding of the general background of the application and does not necessarily constitute an admission by the patent applicant or the like that the information forms part of the prior art that is already known in this field.

[0003] Ultra-high performance concrete (UHPC) has ultra-high strength, high toughness and ultra-high durability, and its performance is far superior to that of traditional concrete materials. This is because UHPC does not include coarse aggregate, but instead uses millimeter-sized aggregate, micron-sized particles (cement, fly ash, mineral powder, etc.), sub-micron-sized particles (silica fume, etc.) and reinforcing fibers to form a more compact and lower-porosity structure. Therefore, UHPC also has excellent water permeation prevention characteristics, which helps to reduce the evaporation of water in the concrete and reduce cracking.

[0004] Compared with traditional concrete materials, the cement component accounts for a higher proportion in UHPC. In addition, in order to minimize the pores left after the evaporation of mixing water, UHPC generally uses a low water-cement ratio, which results in a lower degree of hydration of the cement component in UHPC. Research shows that the degree of hydration is only about 30%. Most of the cement particles only act as fillers and do not hydrate to form cementitious components, which results in a waste of most of the cement components, because the main role of the cement component in the concrete material is to perform a hydration reaction to form cementitious components to cement the aggregate together, which is the main source of the strength of the concrete structure. In addition, the fine aggregate in UHPC generally uses natural sandstone resources, which has brought many environmental problems. Oil shale slag is a solid waste produced in the process of shale oil exploitation. When oil shale slag is directly used to replace natural sandstone fine aggregate to prepare UHPC, due to the loose and porous characteristics of oil shale slag, not only the strength is insufficient, but also the water absorption rate is high, which will further exacerbate the problem of low degree of hydration of the cement component in UHPC, and thus cause the strength of UHPC to decrease and the impermeability to be insufficient. SUMMARY

[0005] In view of the above problems, the present application provides a preparation method of oil shale-based aggregate ultra-high performance concrete material. The method not only overcomes the problem of decreased strength and impermeability of UHPC prepared by using oil shale slag as fine aggregate, but also alleviates the problem of waste of cement components in UHPC. To achieve the above purpose, the technical solution of the present application is as follows.

[0006] A preparation method of an oil shale-based aggregate ultra-high performance concrete material, comprising the following steps:

[0007] (1) uniformly mixing oil shale slag, glass powder, lithium slag powder and magnesium oxide, and then performing sintering treatment, cooling to room temperature after completion, crushing the sintered product to obtain an oil shale-based fine aggregate.

[0008] (2) uniformly mixing phosphogypsum powder, sodium stearate powder and liquid silane coupling agent, and then stirring, and then grinding the obtained mixture to obtain modified phosphogypsum powder.

[0009] (3) taking the following raw materials: 110-130 parts by weight of composite cementitious material, 230-280 parts by weight of the oil shale-based fine aggregate, 70-85 parts by weight of fly ash, 140-170 parts by weight of silica ash, 50-62 parts by weight of the modified phosphogypsum powder, 20-25 parts by weight of fiber, 1.6-2.8 parts by weight of water reducing agent, 1-2 parts by weight of sodium hydroxide and / or potassium hydroxide; the composite cementitious material is composed of Portland cement and mineral powder, wherein the proportion of the Portland cement is 30-40 wt.%. After uniformly mixing the above raw materials, water is added according to a water-binder ratio of 0.17-0.25, and stirring is performed to obtain a concrete material.

[0010] Further, in step (1), the ratio of the oil shale slag, glass powder, lithium slag powder and magnesium oxide = 50-70 parts by weight: 30-42 parts by weight: 6-8.5 parts by weight: 15-23 parts by weight.

[0011] Further, in step (1), the fineness of the oil shale slag is 20-50 mesh. Alternatively, the fineness of the glass powder, lithium slag powder and magnesium oxide is not less than 200 mesh.

[0012] Further, in step (1), the sintering temperature is higher than the softening temperature of the glass powder, and the sintering time is 20-35 min. Alternatively, in step (1), the softening temperature of the glass powder is not more than 600°C. Preferably, the glass powder is made of waste glass.

[0013] Further, in step (1), the particle size of the oil shale-based fine aggregate is 0.5-3 mm. Preferably, the mass ratio of the particles with particle sizes of 0.5-1 mm, 1-2 mm and 2-3 mm in the oil shale-based fine aggregate = 1.5-2: 1: 1.

[0014] Further, in step (2), the sodium stearate accounts for 25-33% of the mass of the phosphogypsum powder, and the liquid silane coupling agent accounts for 2-2.5% of the mass of the phosphogypsum powder. Optionally, the liquid silane coupling agent includes at least one of KH550, KH560, and KH570. The combination of sodium stearate powder and the silane coupling agent not only reduces the water absorption of the modified phosphogypsum powder but also increases the lubricity of the phosphogypsum particles, thus delaying the dissolution of residual phosphoric acid in the phosphogypsum. On the other hand, it avoids the high water absorption of the phosphogypsum particles affecting the fluidity of the concrete. The silane coupling agent facilitates the connection between the sodium stearate particles and the phosphogypsum particles to construct a slow-release system.

[0015] Furthermore, in step (2), the modified phosphogypsum powder has a fineness of 300-400 mesh.

[0016] Further, in step (3), the fiber includes at least one of steel fiber, organic fiber, basalt fiber, etc. Optionally, the organic fiber includes at least one of polyethylene fiber, polyvinyl alcohol fiber, polypropylene fiber, polyacrylonitrile fiber, etc.

[0017] Further, in step (3), the fiber has a length of 12 to 30 mm and a diameter of 0.1 to 0.3 mm.

[0018] Furthermore, in step (3), the fineness of the composite cementitious material is 300-400 mesh.

[0019] Further, in step (3), the water-reducing agent includes at least one of polycarboxylate water-reducing agent, naphthalene-based water-reducing agent, melamine-based water-reducing agent, lignin sulfonate water-reducing agent, melamine water-reducing agent, etc.

[0020] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0021] On the one hand, there is a problem that oil shale slag, due to its high porosity and insufficient strength, easily reduces the hydration degree of cement components when used as fine aggregate in the preparation of ultra-high performance concrete, leading to a decrease in concrete strength and impermeability. This invention uses oil shale slag as a base, adding glass powder, lithium slag powder, and magnesium oxide before sintering. The resulting oil shale-based fine aggregate, after crushing, not only significantly reduces porosity but also undergoes a hydration reaction to increase the content of cementitious components, thereby improving the strength and impermeability of the concrete. This is because during the sintering process, the melted glass powder fills the pores in the oil shale slag particles, coating them and reducing porosity while increasing strength. Simultaneously, the lithium element in the lithium slag powder helps lower the softening temperature of the glass powder during sintering, reducing energy consumption while achieving resource utilization of the lithium slag.

[0022] On the other hand, in view of the problem that in the conventional ultra-high performance concrete, the cement consumption is large, but the actual hydration rate is low, resulting in waste of cement components, the composite cementitious material is formed by using the mineral powder to replace most of the cement, so that the proportion of cement is reduced, and unnecessary waste is reduced. When the above-mentioned composite cementitious material and oil shale-based fine aggregate and other raw materials are used to prepare the ultra-high performance concrete, on the one hand, the sodium hydroxide is dissolved in the mixing water to form an alkali solution to excite the mineral powder, fly ash and silica fume, so as to improve the cementitious activity, and the calcium hydroxide generated by the hydration of the cement reacts with the alkali solution to form a cementitious component, so that the content of the cementitious component in the concrete is increased, and the strength and impermeability are improved. On the other hand, the phosphoric acid in the phosphogypsum gradually dissolves and reacts with part of the sodium / potassium hydroxide to form phosphate and water, wherein the water can provide the required water for the above-mentioned pozzolanic reaction. The phosphate reacts with the magnesium oxide in the oil shale-based fine aggregate to form a high-strength and high-viscosity cementitious component struvite, which can effectively improve the combination of the oil shale-based fine aggregate and the concrete matrix, and improve the mechanical strength and impermeability of the concrete structure. In addition, the phosphogypsum also has a retarding effect, which helps to prolong the setting time of the concrete and keep better fluidity / working property. BRIEF DESCRIPTION OF DRAWINGS

[0023] The drawings accompanying the specification of the present application serve to provide further understanding of the present application, and the illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute improper limitations on the present application. Hereinafter, the embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0024] Figure 1 is the compressive strength test diagram of the following embodiment 1.

[0025] Figure 2 is the impermeable water performance test diagram of the following embodiments 1-8. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with specific examples, which are only used to illustrate the present application and do not limit the scope of the present application. The preferred embodiments and materials described herein are only used for demonstration. It should be noted that all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art, unless otherwise defined.

[0027] In addition, the reagents or raw materials used in the present application can be purchased through conventional routes, and unless otherwise specified, the reagents or raw materials used in the present application are used in accordance with the conventional manner in the art or in accordance with the product instructions.

[0028] Example 1

[0029] A preparation method of an oil shale-based aggregate ultra-high performance concrete material, comprising the following steps:

[0030] (1) Oil shale slag, waste glass powder, lithium slag powder and magnesium oxide are mixed in a mass ratio of 60:35:7:18 to form a mixed powder after stirring uniformly, wherein the fineness of the oil shale slag is 40 mesh, the fineness of the glass powder, lithium slag powder and magnesium oxide is 200 mesh, and the softening temperature of the waste glass powder is about 520-550℃. Then the mixed powder is heated to 590℃ at a heating rate of 10℃ / min and kept for 30min, and after cooling to room temperature, the sintered product is crushed and sieved, and the particle size of the granular material is 0.5-1mm, 1-2mm, 2-3mm=2:1:1 in mass ratio, to obtain oil shale-based fine aggregate for standby.

[0031] (2) Phosphogypsum powder, sodium stearate powder and silane coupling agent KH550 are mixed and stirred uniformly, the sodium stearate is 30% of the mass of the phosphogypsum powder, and the silane coupling agent KH550 is 2.2% of the mass of the phosphogypsum powder. Then the obtained mixed powder is ground to obtain modified phosphogypsum powder with a fineness of 300 mesh for standby.

[0032] (3) Take the following raw materials: 115 parts by weight of composite cementitious material with a fineness of 400 mesh, 260 parts by weight of oil shale-based fine aggregate, 80 parts by weight of fly ash, 150 parts by weight of silica fume, 54 parts by weight of modified phosphogypsum powder, 23 parts by weight of polypropylene fiber (length 12mm, diameter 0.3mm), 2 parts by weight of polycarboxylic acid water reducer, and 1.7 parts by weight of potassium hydroxide. The composite cementitious material is composed of 42.5 ordinary portland cement and mineral powder, and the portland cement accounts for 35wt.%. The above raw materials are mixed and stirred uniformly, and then water is added in a mass ratio of water to composite cementitious material = 0.2:1, and stirred for 3min to obtain a concrete material.

[0033] The fluidity of the concrete material prepared in this example is tested according to the "Cement Mortar Fluidity Test Method" (GB / T 2419-2005). The 28d compressive strength (as shown in Figure 1 ), 28d water penetration height (as shown in Figure 2 ) of the test piece prepared from the concrete material prepared in this example are tested according to the "Standard Test Methods for Long-Term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009) and "Standard Test Methods for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), respectively. The results are shown in Table 1.

[0034] Table 1

[0035] Test Index Fluidity 28d Compressive Strength 28d Water Penetration Height Test Result 218 mm 109.6 MPa 13.3 mm

[0036] Example 2

[0037] A preparation method of an oil shale-based aggregate ultra-high performance concrete material, comprising the following steps:

[0038] (1) Oil shale slag, waste glass powder, lithium slag powder and magnesium oxide are mixed in a mass ratio of 50:30:6:15 and then stirred uniformly to form a mixed powder, wherein the fineness of the oil shale slag is 20 mesh, the fineness of the glass powder, lithium slag powder and magnesium oxide is 400 mesh, and the softening temperature of the waste glass powder is about 520-550℃. Then the mixed powder is heated to 600℃ at a heating rate of 10℃ / min and kept for 20min, and after completion, it is cooled to room temperature. The sintered product is crushed, sieved, and graded according to the particle size of 0.5-1mm, 1-2mm, and 2-3mm in a mass ratio of 1.5:1:1 to obtain an oil shale-based fine aggregate, which is ready for use.

[0039] (2) Phosphogypsum powder, sodium stearate powder and silane coupling agent KH570 are mixed and stirred uniformly, the sodium stearate is 33% of the mass of the phosphogypsum powder, and the silane coupling agent KH550 is 2.5% of the mass of the phosphogypsum powder. Then the obtained mixed powder is ground to obtain modified phosphogypsum powder with a fineness of 400 mesh, which is ready for use.

[0040] (3) Take the following raw materials: 130 parts by weight of composite cementitious material with a fineness of 350 mesh, 280 parts by weight of the oil shale-based fine aggregate, 85 parts by weight of fly ash, 170 parts by weight of silica fume, 62 parts by weight of the modified phosphogypsum powder, 25 parts by weight of basalt fiber (length 20mm, diameter 0.3mm), 2.8 parts by weight of polycarboxylic acid water reducer, 1 part by weight of potassium hydroxide, and 1 part by weight of sodium hydroxide. The composite cementitious material is composed of 42.5 ordinary portland cement and mineral powder, and the proportion of the portland cement is 40wt.%. The above raw materials are mixed and stirred uniformly, then water is added in a mass ratio of water to composite cementitious material = 0.25:1, and stirred for 3min to obtain a concrete material.

[0041] The fluidity of the concrete material prepared in this embodiment is tested according to the "Cement Mortar Fluidity Test Method" (GB / T 2419-2005). The 28d compressive strength and 28d water penetration height (as shown in Figure 2 ) of the test piece prepared from the concrete material prepared in this embodiment are tested according to the "Standard Test Methods for Long-Term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009) and the "Standard Test Methods for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), respectively. The results are shown in Table 2.

[0042] Table 2

[0043] Test Index Fluidity 28d Compressive Strength 28d Water Penetration Height Test Result 223 mm 104.1 MPa 15.7 mm

[0044] Example 3

[0045] A preparation method of an oil shale-based aggregate ultra-high performance concrete material, comprising the following steps:

[0046] (1) Oil shale slag, waste glass powder, lithium slag powder and magnesium oxide are mixed in a mass ratio of 70:42:8.5:23, and then stirred uniformly to form a mixed powder, wherein the fineness of the oil shale slag is 50 mesh, the fineness of the glass powder, lithium slag powder and magnesium oxide is 300 mesh, and the softening temperature of the waste glass powder is about 520-550℃. Then the mixed powder is heated to 580℃ at a heating rate of 10℃ / min and kept for 35min, and after completion, it is cooled to room temperature. The sintered product is crushed, sieved, and graded according to the particle size of 0.5-1mm, 1-2mm, and 2-3mm in a mass ratio of 1.5:1:1 to obtain an oil shale-based fine aggregate for standby use.

[0047] (2) Phosphogypsum powder, sodium stearate powder and silane coupling agent KH560 are mixed and stirred uniformly, the sodium stearate is 25% of the mass of the phosphogypsum powder, and the silane coupling agent KH550 is 2% of the mass of the phosphogypsum powder. Then the obtained mixed powder is ground to obtain modified phosphogypsum powder with a fineness of 400 mesh for standby use.

[0048] (3) The following raw materials are taken: 110 parts by weight of composite cementing material with a fineness of 300 mesh, 230 parts by weight of the oil shale-based fine aggregate, 70 parts by weight of fly ash, 140 parts by weight of silica fume, 50 parts by weight of the modified phosphogypsum powder, 20 parts by weight of steel fiber (length 30mm, diameter 0.1mm), 1.6 parts by weight of naphthalene-based water reducing agent, and 1 part by weight of potassium hydroxide. The composite cementing material is composed of 42.5 ordinary portland cement and mineral powder, and the proportion of the portland cement is 30wt.%. The above raw materials are mixed and stirred uniformly, and then water is added in a mass ratio of water to composite cementing material = 0.17:1, and stirred for 3min to obtain a concrete material.

[0049] The fluidity of the concrete material prepared in this embodiment is tested according to the "Cement Mortar Fluidity Test Method" (GB / T 2419-2005). The 28d compressive strength and 28d water penetration height (as shown in Figure 2 ) of the test piece prepared from the concrete material prepared in this embodiment are tested according to the "Standard Test Methods for Long-Term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009) and the "Standard Test Methods for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), respectively. The results are shown in Table 3.

[0050] Table 3

[0051] Test Index Fluidity 28d Compressive Strength 28d Water Penetration Height Test Result 211 mm 113.8 MPa 10.2 mm

[0052] Example 4

[0053] A preparation method of an oil shale-based aggregate ultra-high performance concrete material, comprising the following steps:

[0054] (1) The oil shale slag is graded according to the particle size of 0.5-1 mm, 1-2 mm, and 2-3 mm in a mass ratio of 2:1:1 to obtain an oil shale-based fine aggregate, which is ready for use.

[0055] (2) The following raw materials are taken: 115 parts by weight of a composite cementing material with a fineness of 400 mesh, 260 parts by weight of the oil shale-based fine aggregate of the present embodiment, 80 parts by weight of fly ash, 150 parts by weight of silica fume, 54 parts by weight of the modified phosphogypsum powder of the above-mentioned embodiment 1, 23 parts by weight of polypropylene fiber (length 12 mm, diameter 0.3 mm), 2 parts by weight of polycarboxylic acid water reducer, and 1.7 parts by weight of potassium hydroxide. The composite cementing material is composed of 42.5 ordinary portland cement and mineral powder, and the proportion of the portland cement is 35 wt.%. After mixing the above-mentioned raw materials, they are stirred uniformly, and then mixing water is added in a mass ratio of water to composite cementing material = 0.2:1, and stirred for 3 min to obtain a concrete material.

[0056] The fluidity of the concrete material prepared in the present embodiment is tested according to the “Method for Testing the Fluidity of Cement Mortar” (GB / T 2419-2005). The 28d compressive strength and 28d water penetration height (as shown in Figure 2 , respectively) of the test piece prepared from the concrete material prepared in the present embodiment are tested according to the “Standard for Testing Methods of Long-term Performance and Durability of Ordinary Concrete” (GB / T 50082-2009) and the “Standard for Testing Methods of Physical and Mechanical Properties of Concrete” (GB / T 50081-2019), respectively. The results are shown in Table 4 below.

[0057] Table 4

[0058] Test Index Fluidity 28d Compressive Strength 28d Water Penetration Height Test Result 156 mm 82.7 MPa 36.4 mm

[0059] Example 5

[0060] A preparation method of an oil shale-based aggregate ultra-high performance concrete material, comprising the following steps:

[0061] (1) oil shale slag, waste glass powder and lithium slag powder are mixed in a mass ratio of 50:30:6 to form a mixed powder after stirring uniformly, wherein the fineness of the oil shale slag is 20 mesh, the fineness of the glass powder and lithium slag powder is 400 mesh, and the softening temperature of the waste glass powder is about 520-550℃. Then the mixed powder is heated to 600℃ at a heating rate of 10℃ / min and kept for 20min, and after cooling to room temperature, the sintered product is crushed, sieved, and graded according to the particle size of 0.5-1mm, 1-2mm, and 2-3mm in a mass ratio of 1.5:1:1 to obtain oil shale-based fine aggregate for standby.

[0062] (2) Take the following raw materials: 130 parts by weight of composite cementing material with a fineness of 350 mesh, 280 parts by weight of the oil shale-based fine aggregate of the present embodiment, 85 parts by weight of fly ash, 170 parts by weight of silica ash, 62 parts by weight of modified phosphogypsum powder of the above-mentioned embodiment 2, 25 parts by weight of basalt fiber (length 20mm, diameter 0.3mm), 2.8 parts by weight of polycarboxylic acid water reducer, 1 part by weight of potassium hydroxide, and 1 part by weight of sodium hydroxide. The composite cementing material is composed of 42.5 ordinary portland cement and mineral powder, and the portland cement accounts for 40wt.%. The above-mentioned raw materials are mixed and stirred uniformly, and then mixed water is added in a mass ratio of water to composite cementing material = 0.25:1, and stirred for 3min to obtain a concrete material.

[0063] The fluidity of the concrete material prepared in the present embodiment is tested according to the "Cement Mortar Fluidity Test Method" (GB / T 2419-2005). The 28d compressive strength and 28d water penetration height of the test piece prepared from the concrete material prepared in the present embodiment are tested according to the "Standard Test Methods for Long-Term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009) and "Standard Test Methods for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), respectively, as shown in Figure 2

[0064] Table 5

[0065] Test Index Fluidity 28d Compressive Strength 28d Water Penetration Height Test Result 229 mm 91.2 MPa 23.5 mm

[0066] Example 6

[0067] A preparation method of an oil shale-based aggregate ultra-high performance concrete material, comprising the following steps:

[0068] ​(1) Oil shale residue, lithium residue powder and magnesium oxide were mixed in a mass ratio of 60:7:18 and stirred uniformly to form a mixed powder, wherein the fineness of the oil shale residue was 40 mesh, and the fineness of the lithium residue powder and magnesium oxide was 200 mesh. Then the mixed powder was heated to 590°C at a heating rate of 10°C / min and kept for 30 min. After completion, it was cooled to room temperature to obtain oil shale-based fine aggregate, which was ready for use.

[0069] (2) The following raw materials were taken: 115 parts by weight of composite cementing material with a fineness of 400 mesh, 260 parts by weight of oil shale-based fine aggregate of the present embodiment, 80 parts by weight of fly ash, 150 parts by weight of silica fume, 54 parts by weight of modified phosphogypsum powder of the above-mentioned Example 1, 23 parts by weight of polypropylene fiber (length 12 mm, diameter 0.3 mm), 2 parts by weight of polycarboxylic acid water reducer, and 1.7 parts by weight of potassium hydroxide. The composite cementing material was composed of 42.5 ordinary portland cement and mineral powder, and the proportion of the portland cement was 35 wt.%. The above-mentioned raw materials were mixed and stirred uniformly, and then mixing water was added in a mass ratio of water to composite cementing material = 0.2:1, and stirred for 3 min to obtain a concrete material.

[0070] The fluidity of the concrete material prepared in the present embodiment was tested according to the "Cement Mortar Fluidity Test Method" (GB / T 2419-2005). The 28d compressive strength and 28d water penetration height (as shown in Figure 2 , respectively) of the test piece prepared from the concrete material prepared in the present embodiment were tested according to the "Standard Test Methods for Long-Term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009) and the "Standard Test Methods for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), respectively. The results are shown in Table 6 below.

[0071] Table 6

[0072]

[0073]

[0074] Example 7

[0075] A method for preparing an oil shale-based aggregate ultra-high performance concrete material, comprising the following steps:

[0076] Take the following raw materials: composite cementitious material with fineness of 300 mesh 110 parts by weight, oil shale-based fine aggregate of the above-mentioned embodiment 3 230 parts by weight, fly ash 70 parts by weight, silica fume 140 parts by weight, phosphogypsum powder with fineness of 400 mesh 50 parts by weight, steel fiber (length 30 mm, diameter 0.1 mm) 20 parts by weight, naphthalene-based water reducing agent 1.6 parts by weight, potassium hydroxide 1 part by weight. Among them, the composite cementitious material is composed of 42.5 ordinary Portland cement and mineral powder, and the Portland cement accounts for 30 wt.%. After mixing the above raw materials and stirring uniformly, mixing water is added in a proportion of water to composite cementitious material mass ratio = 0.17:1, and stirred for 3 min to obtain a concrete material.

[0077] The fluidity of the concrete material prepared in this embodiment was tested according to the "Cement Mortar Fluidity Test Method" (GB / T 2419-2005). The 28d compressive strength and 28d water penetration height (as shown in Figure 2 , respectively) of the test piece prepared from the concrete material prepared in this embodiment were tested according to the "Standard Test Methods for Long-Term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009) and "Standard Test Methods for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), respectively. The results are shown in Table 7 below.

[0078] Table 7

[0079] Test Index Fluidity 28d Compressive Strength 28d Water Penetration Height Test Result 177 mm 110.4 MPa 12.8 mm

[0080] Example 8

[0081] A method for preparing an oil shale-based aggregate ultra-high performance concrete material, comprising the following steps:

[0082] Take the following raw materials: composite cementitious material with fineness of 350 mesh 130 parts by weight, oil shale-based fine aggregate of the above-mentioned embodiment 2 280 parts by weight, fly ash 85 parts by weight, silica fume 170 parts by weight, modified phosphogypsum powder of the above-mentioned embodiment 2 62 parts by weight, basalt fiber (length 20 mm, diameter 0.3 mm) 25 parts by weight, polycarboxylic acid water reducing agent 2.8 parts by weight. Among them, the composite cementitious material is composed of 42.5 ordinary Portland cement and mineral powder, and the Portland cement accounts for 40 wt.%. After mixing the above raw materials and stirring uniformly, mixing water is added in a proportion of water to composite cementitious material mass ratio = 0.25:1, and stirred for 3 min to obtain a concrete material.

[0083] The fluidity of the concrete material prepared in the example was tested according to the "Cement Mortar Fluidity Test Method" (GB / T 2419-2005). The 28d compressive strength and 28d water seepage height of the test piece prepared from the concrete material prepared in the example were tested according to the "Standard Test Method for Long-Term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009) and the "Standard Test Method for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), respectively (as shown in FIGS. 1-2), and the results are shown in Table 8 below. Figure 2

[0084] Table 8

[0085] Test Index Fluidity 28d Compressive Strength 28d Water Penetration Height Test Result 226 mm 93.5 MPa 25.2 mm

[0086] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will still be able to make modifications to the technical solutions described in the foregoing embodiments or make equivalent replacements to some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.​

Claims

1. A method for preparing an ultra-high performance concrete material based on oil shale aggregate, characterized in that, Includes the following steps: (1) After the oil shale slag, glass powder, lithium slag powder and magnesium oxide are mixed evenly, they are sintered. After the sintering is completed, the mixture is cooled to room temperature and the sintered product is crushed to obtain oil shale-based fine aggregate. (2) Mix phosphogypsum powder, sodium stearate powder and liquid silane coupling agent and stir evenly. Then grind the resulting mixed powder to obtain modified phosphogypsum powder. (3) Take the following raw materials: 110-130 parts by weight of composite cementitious material, 230-280 parts by weight of the oil shale-based fine aggregate, 70-85 parts by weight of fly ash, 140-170 parts by weight of silica fume, 50-62 parts by weight of the modified phosphogypsum powder, 20-25 parts by weight of fiber, 1.6-2.8 parts by weight of water-reducing agent, and 1-2 parts by weight of sodium hydroxide and / or potassium hydroxide; the composite cementitious material is composed of silicate cement and mineral powder, wherein the silicate cement accounts for 30-40 wt.%; after mixing the above raw materials, add mixing water at a water-cement ratio of 0.17-0.25 and stir evenly to obtain concrete material.

2. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 1, characterized in that, In step (1), the ratio of oil shale slag, glass powder, lithium slag powder and magnesium oxide is 50~70 parts by weight: 30~42 parts by weight: 6~8.5 parts by weight: 15~23 parts by weight.

3. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 1, characterized in that, In step (1), the fineness of the oil shale slag is 20-50 mesh.

4. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 1, characterized in that, In step (1), the glass powder, lithium slag powder, and magnesium oxide have a fineness of not less than 200 mesh.

5. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 1, characterized in that, In step (1), the sintering temperature is higher than the softening temperature of the glass powder, and the sintering time is 20~35min.

6. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 5, characterized in that, In step (1), the softening temperature of the glass powder does not exceed 600°C.

7. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 1, characterized in that, In step (1), the glass powder is made from waste glass.

8. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 1, characterized in that, In step (1), the particle size of the oil shale-based fine aggregate is 0.5~3mm.

9. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 1, characterized in that, The mass ratio of particles with diameters of 0.5~1mm, 1~2mm, and 2~3mm in the oil shale-based fine aggregate is 1.5~2:1:

1.

10. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 1, characterized in that, In step (2), the sodium stearate is 25-33% of the mass of phosphogypsum powder, and the liquid silane coupling agent is 2-2.5% of the mass of phosphogypsum powder.

11. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 1, characterized in that, In step (2), the liquid silane coupling agent includes at least one of KH550, KH560, and KH570.

12. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to any one of claims 1-11, characterized in that, The fineness of the composite cementitious material and gypsum powder is 300~400 mesh.

13. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to any one of claims 1-11, characterized in that, In step (3), the fiber includes at least one of steel fiber, organic fiber, and basalt fiber.

14. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 13, characterized in that, The organic fiber includes at least one of polyethylene fiber, polyvinyl alcohol fiber, polypropylene fiber, and polyacrylonitrile fiber.

15. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to claim 1, characterized in that, In step (3), the fiber has a length of 12~30mm and a diameter of 0.1~0.3mm.

16. The method for preparing ultra-high performance concrete material based on oil shale aggregate according to any one of claims 1-11, characterized in that, In step (3), the water-reducing agent includes at least one of polycarboxylate water-reducing agent, naphthalene-based water-reducing agent, melamine-based water-reducing agent, lignin sulfonate water-reducing agent, and melamine water-reducing agent.

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