Preparation process of carbon reduction type lightweight high-strength aggregate concrete material

Abstract

The invention relates to the technical field of light-weight cement materials, and particularly discloses a preparation process of a carbon-reduction type light-weight high-strength aggregate concrete material, which comprises the step of uniformly mixing a cement binding material, expanded perlite fine aggregate, fly ash, modified light-weight coarse aggregate prepared by the invention, a water reducing agent and mixing water to obtain the concrete material. The lightweight aggregate prepared from solid wastes such as wood raw materials and boric sludge not only improves the problem of insufficient strength of the prepared concrete, but also realizes absorption and curing of carbon dioxide, thereby achieving the purpose of carbon reduction.

Description

Technical Field

[0001] The present invention relates to the technical field of lightweight cement materials, and particularly relates to a preparation process of a carbon-reducing lightweight high-strength aggregate concrete material. Background Art

[0002] Disclosing the information of this background art section is only intended to increase the understanding of the overall background of the present invention, and is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Lightweight aggregate concrete refers to a building material made of lightweight aggregates that are lighter than crushed stones, cobblestones, etc. It not only has better heat insulation and shock absorption properties, but also helps to reduce the self-weight of the structure, and has been widely used in the construction of walls, floors, roofs, and partition walls of civil residences, commercial office buildings, hospitals, etc. Lightweight aggregates include natural lightweight aggregates (such as pumice, volcanic slag, etc.) and artificial lightweight aggregates (such as ceramsite, expanded perlite, etc.).

[0004] In recent years, waste wood has also been used to prepare concrete materials. For example, wood powder, wood fibers, aggregates, etc. made of waste wood are used as raw materials, and are added to concrete to prepare lightweight building materials with heat insulation functions. These raw materials are rich in sources, simple and convenient to process, do not require high-temperature firing like ceramsite, avoid high energy consumption, and also avoid the problem of emitting a large amount of carbon dioxide. Therefore, using waste wood as lightweight aggregate to prepare concrete materials is more green and environmentally friendly, and more in line with the development trend of green building materials. However, due to the insufficient strength of wood itself and the compatibility with concrete materials, etc., the mechanical strength of the prepared concrete materials usually decreases significantly, which limits its development and application. Summary of the Invention

[0005] In view of the above problems, the present invention discloses a preparation process of a carbon-reducing lightweight high-strength aggregate concrete material. The lightweight aggregate made of solid wastes such as woody raw materials and boron mud not only improves the problem of insufficient strength of the prepared concrete, but also realizes the absorption and solidification of carbon dioxide, thus achieving the purpose of carbon reduction. Specifically, the technical solution of the present invention is as follows.

[0006] A preparation process of a carbon-reducing lightweight high-strength aggregate concrete material includes the following steps: (1) Immerse boron mud powder in an acidic liquid to extract magnesium elements therein, and after completion, perform solid-liquid separation to obtain an extraction solution and a solid residue. Mix the solid residue with water glass and heat for heat preservation, and after completion, dry and grind to obtain modified boron mud powder.

[0007] (2) Mix the leaching solution and wood powder, and then perform ultrasonic oscillation treatment. After completion, add an alkaline solution until the system becomes alkaline. Then remove the moisture in the system to obtain modified wood powder.

[0008] (3) Mix the modified wood powder, modified boron mud powder, chopped fibers, potassium dihydrogen phosphate or ammonium dihydrogen phosphate powder, γ-dicalcium silicate powder, and retarder evenly. Then add clear water and mix evenly before granulating. After drying, lightweight coarse aggregate is obtained.

[0009] (4) Subject the lightweight coarse aggregate to post-treatment in a mixed gas of carbon dioxide and water vapor. After completion, spray saturated lime water on the obtained aggregate and then perform steam curing treatment. After completion, dry the obtained aggregate to obtain modified lightweight coarse aggregate.

[0010] (5) Mix the cementitious material, expanded perlite fine aggregate, fly ash, the modified lightweight coarse aggregate, water reducing agent, and mixing water evenly to obtain concrete material.

[0011] Further, in step (1), the ratio of the boron mud powder to the acidic liquid is 1 g: 10 - 30 ml. Optionally, the mass fraction of the acidic liquid is 3 - 7%. The acidic liquid includes at least one of hydrochloric acid, sulfuric acid, and nitric acid.

[0012] Further, in step (1), the impregnation time is 2 - 4 hours. Preferably, the impregnation process is carried out with stirring.

[0013] Further, in step (1), the ratio of the solid residue to the water glass is 1 g: 5 - 8 ml. Optionally, the mass fraction of the water glass is 1 - 2.5%.

[0014] Further, in step (1), the temperature for heating and insulation is 60 - 70 °C, and the time is 120 - 150 min. Optionally, the fineness of the modified boron mud powder is 400 - 500 mesh.

[0015] Further, in step (2), the ratio of the leaching solution to the wood powder is 20 - 30 ml: 1 g. Optionally, the fineness of the wood powder is 20 - 50 mesh.

[0016] Further, in step (2), the time for ultrasonic oscillation treatment is not less than 40 min to ensure that the leaching solution fully penetrates into the wood powder.

[0017] Further, in step (2), add an alkaline solution until the pH of the system is 7.5 - 8. Optionally, the alkaline solution includes at least one of sodium hydroxide solution and potassium hydroxide solution, etc.

[0018] Further, in step (3), the ratio of the modified wood powder, modified boron mud powder, chopped fibers, potassium dihydrogen phosphate or ammonium dihydrogen phosphate powder, γ-dicalcium silicate powder, retarder, and clear water is 100 parts by weight: 26 - 33 parts by weight: 8.5 - 13 parts by weight: 4 - 10 parts by weight: 2 - 6 parts by weight, 3.5 - 5 parts by weight: 21 - 25 parts by weight.

[0019] Further, in step (3), the chopped fibers include at least one of polyethylene fibers, polypropylene fibers, basalt fibers, carbon fibers, etc. Optionally, the length of the chopped fibers is 2 - 5 mm.

[0020] Further, in step (3), the retarder includes at least one of borax, sodium tripolyphosphate, etc.

[0021] Further, in step (3), the particle size of the lightweight coarse aggregate is 1 - 2 cm. Optionally, the drying temperature is 60 - 70 °C, and the time is 1.5 - 2 hours.

[0022] Further, in step (4), the volume percentage of carbon dioxide in the mixed gas is 70 - 80%. Optionally, the post-treatment time is 2 - 4 hours.

[0023] Further, in step (4), the ratio of the aggregate to saturated lime water is 1 g: 2 - 3 ml.

[0024] Further, in step (4), the temperature of the steam curing treatment is 50 - 70 °C, and the time is 6 - 10 hours.

[0025] Further, in step (5), the ratio of the cementitious material, expanded perlite fine aggregate, fly ash, the modified lightweight coarse aggregate, and water reducing agent is 240 - 262 parts by weight: 290 - 348 parts by weight: 30 - 45 parts by weight: 525 - 610 parts by weight: 3.5 - 5.2 parts by weight. The mixing water is 0.42 - 0.46% of the cement mass.

[0026] Further, in step (5), the water reducing agent includes at least one of polycarboxylate water reducing agent, lignosulfonate water reducing agent, naphthalene series water reducing agent, melamine series water reducing agent, aliphatic series water reducing agent, etc.

[0027] Compared with the prior art, the present invention has at least the following beneficial technical effects: In the present invention, industrial solid waste boron mud containing magnesium element is first used as a raw material to extract the magnesium element therein, and then water glass is used to treat the obtained solid residue. While removing the residual acidic liquid therein, water glass can also be used to activate the solid residue, promote the depolymerization of its silicon-oxygen tetrahedron, and improve the reaction activity, so as to form cementitious components such as calcium silicate hydrate in the subsequent process. Then, the present invention uses the obtained leaching solution to treat wood powder, and uses an alkaline solution to convert the magnesium element into magnesium hydroxide to form modified wood powder. Then, lightweight coarse aggregate is prepared by using the modified wood powder, modified boron mud powder, short-cut fiber, potassium dihydrogen phosphate or ammonium dihydrogen phosphate, etc. as raw materials. In this process, magnesium hydroxide in the modified wood powder releases magnesium ions under the action of potassium dihydrogen phosphate or ammonium dihydrogen phosphate and then undergoes a hydration reaction to form struvite with high strength and high adhesiveness, which cements each component together to form lightweight aggregate with high strength. Further, the present invention uses a mixture of carbon dioxide and water vapor to treat the lightweight coarse aggregate. In this process, the carbon dioxide, water vapor and dicalcium silicate of γ-type react to form calcium carbonate and nano-silicon dioxide to further densify the aggregate, realizing carbon dioxide solidification while improving the mechanical strength of the aggregate. At the same time, the present invention uses this process to make water vapor enter the aggregate and form an acidic environment with the unreacted potassium dihydrogen phosphate or ammonium dihydrogen phosphate, promoting the release of magnesium ions from the unreacted magnesium hydroxide in the aggregate to continue the hydration reaction, effectively overcoming the problem that the hydration degree cannot be fully carried out due to the fast hydration reaction rate and resulting in solidification and hardening, which affects the strength development. Further, the present invention uses saturated lime water to treat the aggregate treated above again, and uses the nano-silicon dioxide formed by the dicalcium silicate of γ-type in the aggregate, modified boron mud and calcium hydroxide provided by saturated lime water to react to form cementitious components such as calcium silicate hydrate. On the one hand, it can further improve the density and strength of the aggregate. On the other hand, it can also enhance the bonding force between the fiber and the matrix in the aggregate, thereby improving the strength of the aggregate. At the same time, the calcium silicate hydrate on the surface of the aggregate can also serve as the nucleation site of the hydration product during the hydration reaction of the cementitious material, promoting the progress of the hydration reaction and improving the strength of the prepared concrete material. Description of the Drawings

[0028] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings, wherein: Figure 1 It is a diagram of the modified lightweight coarse aggregate sample prepared in Example 1 below.

[0029] Figure 2 It is a diagram of the compressive strength test of Example 1 below.

[0030] Figure 3Diagram of the modified lightweight coarse aggregate samples prepared for Example 2 below.

[0031] Figure 4 Diagram of the compressive strength test for Example 2 below.

[0032] Figure 5 Diagram of the modified lightweight coarse aggregate samples prepared for Example 3 below.

[0033] Figure 6 Diagram of the compressive strength test for Example 3 below.

[0034] Figure 7 Diagram of the modified lightweight coarse aggregate samples prepared for Example 4 below.

[0035] Figure 8 Diagram of the compressive strength test for Example 4 below.

[0036] Figure 9 Diagram of the modified lightweight coarse aggregate samples prepared for Example 5 below.

[0037] Figure 10 Diagram of the compressive strength test for Example 5 below.

[0038] Figure 11 Diagram of the compressive strength test for Example 6 below.

[0039] Figure 12 Diagram of the modified lightweight coarse aggregate samples prepared for Example 7 below.

[0040] Figure 13 Diagram of the compressive strength test for Example 7 below. Detailed implementation mode

[0041] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer.

[0042] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. The reagents or raw materials used in the present invention can be obtained through conventional channels. Unless otherwise specified, the reagents or raw materials used in the present invention are used in the conventional manner in the art or according to the product instructions. In addition, any methods and materials similar or equivalent to the described content can be applied to the method of the present invention.

[0043] In the following embodiments, the main components of the boron mud are: SiO2 46.1 wt .%, MgO 21.7 wt .%, Fe2O3 19.6wt .%, B2O3 2.4 wt .%, and the balance includes CaO, Al2O3, FeO, etc.

[0044] Example 1: A preparation process of a carbon-reducing lightweight high-strength aggregate concrete material, comprising the following steps: (1) Mix boron mud powder with dilute sulfuric acid with a concentration of 5 wt .% at a ratio of 1 g:20 ml and continuously stir for 3.5 hours. After completion, filter, and reserve the obtained leaching solution and solid residue separately.

[0045] (2) Mix the solid residue from step (1) with water glass with a concentration of 1.5 wt .% at a ratio of 1 g:6 ml, heat to 70 °C, and keep warm for 120 min. After completion, dry the obtained solid product, then grind it, and pass through a 400-mesh sieve to obtain modified boron mud powder.

[0046] (3) Mix the leaching solution from step (1) and wood powder with a fineness of 30 mesh at a ratio of 25 ml:1 g, perform ultrasonic oscillation treatment for 45 min, after completion, let it stand for 10 min, and then add sodium hydroxide solution to adjust the system pH = 8. Then heat to 100 °C for evaporation treatment to remove the moisture in the system, and obtain modified wood powder.

[0047] (4) Take raw materials in the following proportions: 100 parts by weight of the modified wood powder, 28 parts by weight of the modified boron mud powder, 11 parts by weight of polypropylene fiber with a length of 2 mm, 7 parts by weight of potassium dihydrogen phosphate powder, 5 parts by weight of γ-dicalcium silicate powder, and 4 parts by weight of borax. Mix them and stir for 5 min, then add 23 parts by weight of clear water, stir for 1 min, and then granulate. Dry the obtained particulate matter at 70 °C for 1.5 hours, and screen out the particulate matter with a particle size between 1 and 2 cm to obtain lightweight coarse aggregate.

[0048] (5) Place the lightweight coarse aggregate in a mixed gas formed by carbon dioxide and water vapor at a volume percentage of 80%:20% for 2 hours for post-treatment. After completion, evenly spray saturated lime water on the obtained aggregate, with a ratio of 1 g:2 ml, and then place it in a curing box and keep warm at 60 °C in a closed environment for 7.5 hours. After completion, naturally dry the obtained aggregate for 4 days to obtain modified lightweight coarse aggregate (as Figure 1 shown).

[0049] (6) Take raw materials in the following proportions: 252 parts by weight of 42.5 ordinary Portland cement powder, 305 parts by weight of expanded perlite fine aggregate with a particle size of 0.2 - 0.5 mm, 37 parts by weight of fly ash, and 560 parts by weight of the modified lightweight coarse aggregate. Mix the above raw materials evenly to obtain a powder. Then add 4.5 parts by weight of polycarboxylate water reducer to 113 parts by weight of mixing water and stir evenly, and then mix with the powder and stir for 3 minutes to obtain the concrete material.

[0050] Performance test: Pour the concrete material prepared in this example into a mold, cure for 28 days after molding, and then test the compressive strength of the concrete specimen obtained according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081 - 2019) (as Figure 2 shown), and the result is 33.16 MPa.

[0051] Example 2: A preparation process of a carbon - reduced lightweight high - strength aggregate concrete material includes the following steps: (1) Mix boron mud powder and 7 wt .% hydrochloric acid at a ratio of 1 g:10 ml and continuously stir for 2 hours. After completion, filter, and reserve the obtained leaching solution and solid residue respectively.

[0052] (2) Mix the solid residue in step (1) and 2.5 wt .% water glass at a ratio of 1 g:5 ml, heat to 60 °C and keep warm for 150 min. After completion, dry the obtained solid product, then grind it, and pass through a 400 - mesh sieve to obtain modified boron mud powder.

[0053] (3) Mix the leaching solution in step (1) and wood powder with a fineness of 20 mesh at a ratio of 30 ml:1 g, perform ultrasonic oscillation treatment for 60 min. After completion, let it stand for 10 min, and then add sodium hydroxide solution to adjust the system pH = 7.5. Then heat to 110 °C for evaporation to remove the moisture in the system to obtain modified wood powder.

[0054] (4) Take raw materials in the following proportions: 100 parts by weight of the modified wood powder, 33 parts by weight of the modified boron mud powder, 8.5 parts by weight of polyvinyl alcohol fiber with a length of 5 mm, 10 parts by weight of potassium dihydrogen phosphate powder, 6 parts by weight of γ - type dicalcium silicate powder, and 5 parts by weight of sodium tripolyphosphate. Mix them evenly for 5 min, then add 25 parts by weight of clear water and stir for 1 min, and then granulate. Dry the obtained particles at 65 °C for 2 hours, and screen out the particles with a particle size between 1 - 2 cm to obtain the lightweight coarse aggregate.

[0055] (5) Place the light coarse aggregate in a mixed gas formed by carbon dioxide and water vapor in a volume percentage of 75%:25% and keep it for 3 hours for post-treatment. After completion, evenly spray saturated lime water on the obtained aggregate, with a ratio of 1 g:3 ml. Then place it in a curing box and keep it warm at 50 °C in a closed environment for 10 hours. After completion, naturally dry the obtained aggregate for 4 days to obtain the modified light coarse aggregate (as Figure 3 shown).

[0056] (6) Take raw materials in the following proportions: 240 parts by weight of 42.5 ordinary Portland cement powder, 290 parts by weight of expanded perlite fine aggregate with a particle size of 0.2 - 0.5 mm, 30 parts by weight of fly ash, and 525 parts by weight of the modified light coarse aggregate. Mix the above raw materials and stir evenly to obtain a powder. Then add 3.5 parts by weight of sodium lignosulfonate water reducer to 100.8 parts by weight of mixing water and stir evenly. Then mix it with the powder and stir for 3 min to obtain the concrete material.

[0057] Performance test: Pour the concrete material prepared in this example into a mold, cure it for 28 days after molding, and then test the compressive strength of the concrete specimens obtained according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081 - 2019) (as Figure 4 shown), and the result is 36.48 MPa.

[0058] Example 3: A preparation process of a carbon-reducing light high-strength aggregate concrete material, comprising the following steps: (1) Mix boron mud powder and sulfuric acid with a concentration of 3 wt .% in a ratio of 1 g:30 ml and continuously stir for 4 hours. After completion, filter, and reserve the obtained leaching solution and solid residue separately.

[0059] (2) Mix the solid residue in step (1) with water glass with a concentration of 1.0 wt .% in a ratio of 1 g:8 ml, heat it to 65 °C and keep it warm for 130 min. After completion, dry the obtained solid product, then grind it, and pass through a 500-mesh sieve to obtain modified boron mud powder.

[0060] (3) Mix the leaching solution in step (1) and wood powder with a fineness of 50 meshes in a ratio of 20 ml:1 g, perform ultrasonic oscillation treatment for 40 min, let it stand for 10 min after completion, and then add sodium hydroxide solution to adjust the system pH = 8. Then heat it to 105 °C for evaporation treatment to remove the moisture in the system to obtain modified wood powder.

[0061] (4) Take raw materials in the following proportions: 100 parts by weight of the modified wood powder, 26 parts by weight of the modified boron mud powder, 13 parts by weight of basalt fibers with a length of 4 mm, 4 parts by weight of ammonium dihydrogen phosphate powder, 2 parts by weight of γ-dicalcium silicate powder, and 3.5 parts by weight of borax. Mix them and stir for 5 min, then add 21 parts by weight of clear water and stir for 1 min, followed by granulation. Dry the obtained particulate matter at 60 °C for 110 min, and screen out the particulate matter with a particle size between 1 and 2 cm to obtain the light coarse aggregate.

[0062] (5) Place the light coarse aggregate in a mixed gas formed by carbon dioxide and water vapor in a volume percentage of 70%:30% and hold for 4 hours for post-treatment. After completion, evenly spray saturated lime water on the obtained aggregate, with the ratio of the two being 1 g:2 ml, and then place it in a curing box and keep it warm at 70 °C in a closed environment for 6 hours. After completion, naturally dry the obtained aggregate for 4 days to obtain the modified light coarse aggregate (as shown in Figure 5 ).

[0063] (6) Take raw materials in the following proportions: 262 parts by weight of 42.5 ordinary portland cement powder, 348 parts by weight of expanded perlite fine aggregate with a particle size of 0.2 - 0.5 mm, 45 parts by weight of fly ash, and 610 parts by weight of the modified light coarse aggregate. Mix the above raw materials evenly to obtain a powder. Then add 5.2 parts by weight of polycarboxylate water reducer to 120.5 parts by weight of mixing water and stir evenly, and then mix with the powder and stir for 3 min to obtain the concrete material.

[0064] Performance test: Pour the concrete material prepared in this example into a mold, cure for 28 days after molding, and then test the compressive strength of the concrete specimens obtained according to the "Standard Test Method for Physical and Mechanical Properties of Concrete" (GBT 50081-2019) (as shown in Figure 6 ). The result is 31.67 MPa.

[0065] Example 4: A preparation process of a carbon-reducing light high-strength aggregate concrete material, comprising the following steps: (1) Mix boron mud powder and dilute sulfuric acid with a concentration of 5 wt .% at a ratio of 1 g:20 ml and continuously stir for 3.5 hours. After completion, filter, and reserve the obtained leaching solution and solid residue separately.

[0066] (2) Mix the solid residue in step (1) with water glass with a concentration of 1.5 wt .% at a ratio of 1 g:6 ml, heat to 70 °C, and keep warm for 120 min. After completion, dry the obtained solid product, then grind it, and pass through a 400-mesh sieve to obtain the modified boron mud powder.

[0067] (3) Mix the leaching solution from step (1) and the wood powder with a fineness of 30 mesh at a ratio of 25 ml: 1 g, then perform ultrasonic oscillation treatment for 45 min. After completion, let it stand for 10 min, and then add sodium hydroxide solution to adjust the pH of the system to 8. Then heat to 100 °C for evaporation to remove the moisture in the system, thus obtaining modified wood powder.

[0068] (4) Take the following raw materials in proportion: 100 parts by weight of the modified wood powder, 28 parts by weight of the modified boron mud powder, 11 parts by weight of polypropylene fibers with a length of 2 mm, 7 parts by weight of potassium dihydrogen phosphate powder, 5 parts by weight of γ-type dicalcium silicate powder, and 4 parts by weight of borax. Mix them and stir for 5 min, then add 23 parts by weight of clear water and stir for 1 min, and then granulate. Dry the obtained particles at 70 °C for 1.5 hours, and screen out the particles with a particle size between 1 and 2 cm, thus obtaining lightweight coarse aggregate.

[0069] (5) Mix the lightweight coarse aggregate with saturated lime water at a ratio of 1 g: 40 ml, and then keep it warm at 60 °C for 7.5 hours. After completion, let the obtained aggregate dry naturally for 4 days, thus obtaining modified lightweight coarse aggregate (as Figure 7 shown).

[0070] (6) Take the following raw materials in proportion: 252 parts by weight of 42.5 ordinary Portland cement powder, 305 parts by weight of expanded perlite fine aggregate with a particle size of 0.2 - 0.5 mm, 37 parts by weight of fly ash, and 560 parts by weight of the modified lightweight coarse aggregate. Mix the above raw materials evenly to obtain a powder. Then add 4.5 parts by weight of polycarboxylate water reducer to 113 parts by weight of mixing water and stir evenly, and then mix with the powder and stir for 3 min, thus obtaining concrete materials.

[0071] Performance test: Pour the concrete materials prepared in this example into a mold, cure for 28 days after molding, and then test the compressive strength of the concrete specimens obtained according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081 - 2019) (as Figure 8 shown), and the result is 26.33 MPa.

[0072] Example 5: A preparation process of a carbon-reducing lightweight high-strength aggregate concrete material, comprising the following steps: (1) Mix the boron mud powder and sulfuric acid with a concentration of 3 wt .% at a ratio of 1 g: 30 ml, and then continuously stir for 4 hours. After completion, filter, and reserve the obtained leaching solution and solid residue respectively.

[0073] (2) Mix the solid residue from step (1) and sulfuric acid with a concentration of 1.0 wtMix the water glass of .% and 8 ml of water at a ratio of 1 g:8 ml, heat the mixture to 65 °C and keep it warm for 130 min. After completion, dry the obtained solid product, then grind it, and pass it through a 500-mesh sieve to obtain the modified boron mud powder.

[0074] (3)Mix the leaching solution in step (1) and the wood powder with a fineness of 50 meshes at a ratio of 20 ml:1 g, perform ultrasonic oscillation treatment for 40 min, let it stand for 10 min after completion, and then add sodium hydroxide solution to adjust the pH of the system to 8. Then heat it to 105 °C for evaporation to remove the water in the system, and the modified wood powder is obtained.

[0075] (4)Take the following raw materials in proportion: 100 parts by weight of the modified wood powder, 26 parts by weight of the modified boron mud powder, 13 parts by weight of basalt fibers with a length of 4 mm, 4 parts by weight of ammonium dihydrogen phosphate powder, 2 parts by weight of γ-type dicalcium silicate powder, and 3.5 parts by weight of borax. Mix them and stir for 5 min, then add 21 parts by weight of clear water and stir for 1 min, and then granulate. Dry the obtained particles at 60 °C for 110 min, and screen out the particles with a particle size between 1 and 2 cm, and the lightweight coarse aggregate is obtained.

[0076] (5)Place the lightweight coarse aggregate in a mixed gas formed by carbon dioxide and water vapor at a volume percentage of 70%:30% and keep it for 4 hours for post-treatment. After completion, let the obtained aggregate dry naturally for 4 days to obtain the modified lightweight coarse aggregate (as Figure 9 shown).

[0077] (6)Take the following raw materials in proportion: 262 parts by weight of 42.5 ordinary Portland cement powder, 348 parts by weight of expanded perlite fine aggregate with a particle size of 0.2 - 0.5 mm, 45 parts by weight of fly ash, and 610 parts by weight of the modified lightweight coarse aggregate. Mix the above raw materials evenly to obtain a powder. Then add 5.2 parts by weight of polycarboxylate water reducer to 120.5 parts by weight of mixing water and stir evenly, and then mix it with the powder and stir for 3 min to obtain the concrete material.

[0078] Performance test: Pour the concrete material prepared in this example into a mold, cure it for 28 days after molding, and then test the compressive strength of the concrete specimens obtained according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081 - 2019) (as Figure 10 shown), and the result is 28.02 MPa.

[0079] Example 6: A preparation process of a lightweight aggregate concrete material, comprising the following steps: (1)Crush the waste wood and screen out the particles with a particle size of 1 - 2 cm to obtain the woody aggregate for standby.

[0080] (2) Take the following raw materials: 240 parts by weight of 42.5 ordinary Portland cement powder, 290 parts by weight of expanded perlite fine aggregate with a particle size of 0.2 - 0.5 mm, 30 parts by weight of fly ash, and 525 parts by weight of the wood aggregate. Mix the above raw materials evenly to obtain a powder. Then add 3.5 parts by weight of sodium lignosulfonate water reducer to 100.8 parts by weight of mixing water and stir evenly, and then mix with the powder and stir for 3 min to obtain the concrete material.

[0081] Performance test: Pour the concrete material prepared in this example into a mold, cure it for 28 days after molding, and then test the compressive strength of the concrete specimen obtained according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081 - 2019) (as Figure 11 shown), and the result is 23.53 MPa.

[0082] Example 7: A preparation process of a carbon - reducing lightweight high - strength aggregate concrete material, comprising the following steps: (1) Mix boron mud powder and dilute sulfuric acid with a concentration of 5 wt .% at a ratio of 1 g:20 ml and continuously stir for 3.5 hours. After completion, filter, and reserve the obtained leaching solution and solid residue separately.

[0083] (2) Mix the solid residue in step (1) and water glass with a concentration of 1.5 wt .% at a ratio of 1 g:6 ml, heat to 70 °C, and keep warm for 120 min. After completion, dry the obtained solid product, then grind it, and pass through a 400 - mesh sieve to obtain modified boron mud powder.

[0084] (3) Mix the leaching solution in step (1) and wood powder with a fineness of 30 meshes at a ratio of 25 ml:1 g, perform ultrasonic oscillation treatment for 45 min, let it stand for 10 min after completion, and then dropwise add sodium hydroxide solution to adjust the system pH = 8. Then heat to 100 °C for evaporation to remove the moisture in the system to obtain modified wood powder.

[0085] (4) Take the following raw materials: 100 parts by weight of the modified wood powder, 28 parts by weight of the modified boron mud powder, 11 parts by weight of polypropylene fiber with a length of 2 mm, 7 parts by weight of potassium dihydrogen phosphate powder, and 4 parts by weight of borax. Mix them evenly and stir for 5 min, then add 23 parts by weight of clear water, stir for 1 min, and then granulate. Dry the obtained particles at 70 °C for 1.5 hours, and screen out the particles with a particle size between 1 - 2 cm to obtain the lightweight coarse aggregate.

[0086] (5) Place the lightweight coarse aggregate in a mixed gas formed by carbon dioxide and water vapor in a volume percentage of 80%:20% and keep it for 2 hours for post-treatment. After completion, evenly spray saturated lime water on the obtained aggregate, and the ratio of the two is 1 g:2 ml. Then place it in a curing box and keep it warm at 60 °C for 7.5 hours in a closed environment. After completion, naturally dry the obtained aggregate for 4 days to obtain the modified lightweight coarse aggregate (as Figure 12 shown).

[0087] (6) Take the following raw materials in proportion: 252 parts by weight of 42.5 ordinary portland cement powder, 305 parts by weight of expanded perlite fine aggregate with a particle size of 0.2 - 0.5 mm, 37 parts by weight of fly ash, and 560 parts by weight of the modified lightweight coarse aggregate. Mix the above raw materials evenly to obtain a powder. Then add 4.5 parts by weight of polycarboxylate superplasticizer to 113 parts by weight of mixing water and stir evenly. Then mix with the powder and stir for 3 min to obtain the concrete material.

[0088] Performance test: Pour the concrete material prepared in this example into a mold, cure it for 28 days after molding, and then test the compressive strength of the concrete specimens obtained according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081 - 2019) (as Figure 13 shown), and the result is 28.24 MPa.

[0089] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still repair the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any repair, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation process of a carbon-reducing lightweight high-strength aggregate concrete material, characterized in that, It includes the following steps: (1) Immerse the boron mud powder in an acidic liquid to extract the magnesium element therein. After completion, perform solid-liquid separation to obtain an extraction solution and solid residues. Mix the solid residues with water glass and then heat and keep warm. After completion, dry and grind to obtain modified boron mud powder; (2) Mix the extraction solution and wood powder and then perform ultrasonic oscillation treatment. After completion, add an alkaline solution until it becomes alkaline. Then remove the moisture in the system to obtain modified wood powder; (3) Mix the modified wood powder, modified boron mud powder, chopped fibers, potassium dihydrogen phosphate or ammonium dihydrogen phosphate powder, γ-type dicalcium silicate powder, and retarder evenly. Then add clear water and mix evenly and granulate. After drying, obtain lightweight coarse aggregate; (4) Perform post-treatment on the lightweight coarse aggregate in a mixed gas of carbon dioxide and water vapor. After completion, spray saturated lime water on the obtained aggregate and then perform steam curing treatment. After completion, air-dry the obtained aggregate to obtain modified lightweight coarse aggregate; (5) Mix the cementitious material, expanded perlite fine aggregate, fly ash, the modified lightweight coarse aggregate, water reducer, and mixing water evenly to obtain a concrete material.

2. The preparation process of the carbon-reducing lightweight high-strength aggregate concrete material according to claim 1, characterized in that, In step (1), the ratio of the boron mud powder to the acidic liquid is 1 g: 10 - 30 ml; Or, in step (1), the mass fraction of the acidic liquid is 3 - 7%; Or, in step (1), the acidic liquid includes at least one of hydrochloric acid, sulfuric acid, and nitric acid; Or, in step (1), the impregnation time is 2 - 4 hours.

3. The preparation process of the carbon-reducing lightweight high-strength aggregate concrete material according to claim 1, characterized in that, In step (1), the ratio of the solid residues to water glass is 1 g: 5 - 8 ml; Or, in step (1), the mass fraction of the water glass is 1 - 2.5%; Or, in step (1), the temperature for heating and keeping warm is 60 - 70 °C, and the time is 120 - 150 min; Or, in step (1), the fineness of the modified boron mud powder is 400 - 500 mesh.

4. The preparation process of the carbon-reducing lightweight high-strength aggregate concrete material according to claim 1, characterized in that, In step (2), the ratio of the extraction solution to the wood powder is 20 - 30 ml: 1 g; Or, in step (2), the fineness of the wood powder is 20 - 50 mesh; Or, in step (2), the time for ultrasonic oscillation treatment is not less than 40 min; Or, in step (2), add an alkaline solution until the pH of the system is 7.5 - 8; Or, in step (2), the alkaline solution includes at least one of sodium hydroxide solution and potassium hydroxide solution.

5. The preparation process of the carbon-reducing lightweight high-strength aggregate concrete material according to claim 1, characterized in that, In step (3), the ratio of the modified wood powder, modified boron mud powder, chopped fibers, potassium dihydrogen phosphate or ammonium dihydrogen phosphate powder, γ-type dicalcium silicate powder, retarder, and clear water is 100 parts by weight: 26 - 33 parts by weight: 8.5 - 13 parts by weight: 4 - 10 parts by weight: 2 - 6 parts by weight, 3.5 - 5 parts by weight: 21 - 25 parts by weight.

6. The preparation process of the carbon-reducing lightweight high-strength aggregate concrete material according to claim 1, characterized in that In step (3), the chopped fibers include at least one of polyethylene fibers, polypropylene fibers, basalt fibers, and carbon fibers; Or, in step (3), the length of the chopped fibers is 2 - 5 mm; Or, in step (3), the retarder includes at least one of borax and sodium tripolyphosphate; Or, in step (3), the particle size of the lightweight coarse aggregate is 1 - 2 cm; Alternatively, in step (3), the drying temperature is 60-70 °C and the time is 1.5-2 hours.

7. The preparation process of the carbon-reducing lightweight high-strength aggregate concrete material according to claim 1, characterized in that, In step (4), the volume percentage of carbon dioxide in the mixed gas is 70-80%; or, in step (4), the post-treatment time is 2-4 hours.

8. The preparation process of the carbon-reducing lightweight high-strength aggregate concrete material according to claim 1, characterized in that, In step (4), the ratio of the aggregate to saturated lime water is 1 g: 2-3 ml.

9. The preparation process of the carbon-reducing lightweight high-strength aggregate concrete material according to claim 1, characterized in that, In step (4), the steam curing treatment temperature is 50-70 °C and the time is 6-10 hours.

10. The preparation process of the carbon-reducing lightweight high-strength aggregate concrete material according to any one of claims 1-9, characterized in that, In step (5), the ratio of the cementitious material, expanded perlite fine aggregate, fly ash, the modified lightweight coarse aggregate, and water reducer is 240-262 parts by weight: 290-348 parts by weight: 30-45 parts by weight: 525-610 parts by weight: 3.5-5.2 parts by weight; The mixing water is 0.42-0.46% of the cement mass; Alternatively, in step (5), the water reducer includes at least one of polycarboxylate water reducer, lignosulfonate water reducer, naphthalene-based water reducer, melamine-based water reducer, and aliphatic water reducer.

Images