Preparation process of carbon-reducing lightweight high-strength aggregate concrete material

Abstract

The present invention relates to the technical field of lightweight cement materials, specifically disclosing a process for preparing a carbon-reducing lightweight, high-strength aggregate concrete material. The process comprises uniformly mixing a cement binder, expanded perlite fine aggregate, fly ash, a modified lightweight coarse aggregate prepared in the present invention, a water reducer, and mixing water to produce the concrete material. The lightweight aggregate, produced from solid waste such as wood raw materials and boron mud, not only improves the insufficient strength of the prepared concrete but also absorbs and solidifies carbon dioxide, thereby achieving carbon reduction.

Description

Technical Field

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

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Lightweight aggregate concrete (LAC) is a building material made from lighter aggregates than crushed stone and pebbles. It not only offers improved thermal insulation and shock absorption, but also helps reduce the weight of the structure. It is widely used in the construction of walls, floors, roofs, and partitions in residential buildings, commercial office buildings, hospitals, and other structures. Lightweight aggregates include natural lightweight aggregates (such as pumice and volcanic slag) and artificial lightweight aggregates (such as ceramsite and expanded perlite).

[0004] In recent years, waste wood has also been used to prepare concrete materials. For example, wood powder, wood fiber, aggregates, etc. made from waste wood are used as raw materials and added to concrete to prepare lightweight building materials with thermal insulation functions. These raw materials are abundant in source and simple and convenient to process. They do not need to be fired at high temperatures like expanded clay, avoiding high energy consumption and the problem of emitting large amounts of carbon dioxide. Therefore, using waste wood as lightweight aggregate to prepare concrete materials is greener and more environmentally friendly, and is more in line with the development trend of green building materials. However, due to the insufficient strength of the wood itself and its compatibility with concrete materials, the mechanical strength of the prepared concrete materials usually decreases significantly, limiting their development and application. Summary of the Invention

[0005] To address these issues, the present invention discloses a process for preparing a carbon-reducing, lightweight, high-strength aggregate concrete material. This lightweight aggregate, made from solid waste such as wood raw materials and boron mud, not only improves the insufficient strength of the resulting concrete but also absorbs and solidifies carbon dioxide, thereby achieving carbon reduction. Specifically, the technical solution of the present invention is as follows.

[0006] A process for preparing a carbon-reducing lightweight high-strength aggregate concrete material comprises the following steps:

[0007] (1) Boron mud powder is immersed in an acidic liquid to extract the magnesium element therein. After completion, solid-liquid separation is performed to obtain an extract and a solid residue. The solid residue is mixed with water glass and heated and kept warm. After completion, it is dried and ground to obtain modified boron mud powder.

[0008] (2) The extract and wood powder are mixed and then ultrasonically shaken. After the mixture is complete, an alkaline solution is added until the mixture becomes alkaline. The water in the system is then removed to obtain the modified wood powder.

[0009] (3) The modified wood powder, modified borax powder, chopped fibers, potassium dihydrogen phosphate or ammonium dihydrogen phosphate powder, γ-type dicalcium silicate powder, and retarder are mixed evenly, and then clean water is added, mixed evenly, and granulated. After drying, lightweight coarse aggregate is obtained.

[0010] (4) The lightweight coarse aggregate is placed in a mixture of carbon dioxide and water vapor for post-treatment. After the post-treatment, saturated lime water is sprayed on the aggregate and then steam-cured. After the post-treatment, the aggregate is air-dried to obtain the modified lightweight coarse aggregate.

[0011] (5) The cement binder, expanded perlite fine aggregate, fly ash, the modified lightweight coarse aggregate, water reducer and mixing water are uniformly mixed to obtain concrete material.

[0012] Furthermore, in step (1), the ratio of the borax 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.

[0013] Furthermore, in step (1), the immersion time is 2 to 4 hours. Preferably, the immersion process is carried out while stirring.

[0014] Furthermore, in step (1), the ratio of the solid residue to water glass is 1 g: 5-8 ml. Optionally, the mass fraction of the water glass is 1-2.5%.

[0015] Furthermore, in step (1), the heating and heat preservation temperature is 60-70° C. and the time is 120-150 min. Optionally, the fineness of the modified borax powder is 400-500 mesh.

[0016] Furthermore, in step (2), the ratio of the extract to the wood powder is 20-30 ml: 1 g. Optionally, the fineness of the wood powder is 20-50 mesh.

[0017] Furthermore, in step (2), the ultrasonic oscillation treatment time is not less than 40 minutes, so that the extract can fully penetrate into the wood powder.

[0018] Furthermore, in step (2), an alkaline solution is added until the system pH is 7.5 to 8. Optionally, the alkaline solution includes at least one of a sodium hydroxide solution, a potassium hydroxide solution, and the like.

[0019] Furthermore, in step (3), the ratio of the modified wood powder, modified borax powder, chopped fibers, potassium dihydrogen phosphate or ammonium dihydrogen phosphate powder, γ-type dicalcium silicate powder, retarder, and clean 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, and 3.5-5 parts by weight: 21-25 parts by weight.

[0020] Furthermore, 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 to 5 mm.

[0021] Furthermore, in step (3), the retarder includes at least one of borax, sodium tripolyphosphate, etc.

[0022] Furthermore, 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 drying time is 1.5-2 hours.

[0023] Furthermore, 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.

[0024] Furthermore, in step (4), the ratio of the aggregate to saturated lime water is 1 g: 2-3 ml.

[0025] Furthermore, in step (4), the steaming treatment is carried out at a temperature of 50-70° C. and for a time of 6-10 hours.

[0026] Furthermore, in step (5), the ratio of the cementitious material, expanded perlite fine aggregate, fly ash, the modified lightweight coarse aggregate, and the 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 mass of the cement.

[0027] Furthermore, in step (5), the water reducer includes at least one of: a polycarboxylic acid water reducer, a lignin sulfonate water reducer, a naphthalene water reducer, a melamine water reducer, an aliphatic water reducer, and the like.

[0028] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0029] The present invention first extracts magnesium from industrial solid waste boron mud, which contains magnesium. The resulting solid residue is then treated with water glass. This removes any residual acidic liquid and stimulates the solid residue, promoting the depolymerization of silicon-oxygen tetrahedra, increasing its reactivity and enabling the subsequent formation of cementitious components such as hydrated calcium silicate. The resulting extract is then used to treat wood flour, and an alkaline solution is used to convert the magnesium into magnesium hydroxide to form modified wood flour. Lightweight coarse aggregate is then prepared using the modified wood flour, modified boron mud powder, chopped fibers, potassium dihydrogen phosphate or ammonium dihydrogen phosphate, and other raw materials. During this process, the magnesium hydroxide in the modified wood flour releases magnesium ions under the action of potassium dihydrogen phosphate or ammonium dihydrogen phosphate, which then undergoes a hydration reaction to form high-strength and highly adhesive struvite, which cements the various components together to form a high-strength lightweight aggregate. Furthermore, the present invention uses a mixture of carbon dioxide and water vapor to treat the lightweight coarse aggregate. During this process, the carbon dioxide, water vapor, and gamma-type dicalcium silicate react to form calcium carbonate and nano-silicon dioxide, further compacting the aggregate and achieving carbon dioxide solidification while improving the mechanical strength of the aggregate. Simultaneously, the present invention utilizes this process to allow water vapor to enter the aggregate and form an acidic environment with 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 of strength development affected by the inability to fully achieve solidification and hardening due to the fast hydration reaction rate. Furthermore, the present invention further treats the aggregate treated above with saturated lime water, reacting the nano-silicon dioxide and modified boron mud formed from the gamma-type dicalcium silicate in the aggregate with the calcium hydroxide provided by the saturated lime water to form gelling components such as hydrated calcium silicate. This, on the one hand, can further improve the density and strength of the aggregate. On the other hand, it can also enhance the bonding force between the fibers 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 a nucleation site for hydration products when the cement binder undergoes a hydration reaction, thereby promoting the hydration reaction and improving the strength of the prepared concrete material. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute undue limitations thereon. The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0031] Figure 1 This is a diagram of a modified lightweight coarse aggregate sample prepared in Example 1 below.

[0032] Figure 2 This is a compressive strength test diagram of the following Example 1.

[0033] Figure 3 This is a diagram of the modified lightweight coarse aggregate sample prepared in Example 2 below.

[0034] Figure 4 This is a compressive strength test diagram of the following Example 2.

[0035] Figure 5 This is a diagram of the modified lightweight coarse aggregate sample prepared in Example 3 below.

[0036] Figure 6 This is a compressive strength test diagram of the following Example 3.

[0037] Figure 7 This is a diagram of the modified lightweight coarse aggregate sample prepared in Example 4 below.

[0038] Figure 8 This is a compressive strength test diagram of the following Example 4.

[0039] Figure 9 This is a diagram of a modified lightweight coarse aggregate sample prepared in Example 5 below.

[0040] Figure 10 This is a compressive strength test diagram of the following Example 5.

[0041] Figure 11 This is a compressive strength test diagram of the following Example 6.

[0042] Figure 12 This is a diagram of the modified lightweight coarse aggregate sample prepared in Example 7 below.

[0043] Figure 13 This is a compressive strength test diagram of the following Example 7. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the invention. The experimental methods in the following examples, for which specific conditions are not specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0045] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. The reagents and raw materials used in the present invention can be purchased through conventional channels. Unless otherwise specified, the reagents and raw materials used in the present invention are used in a conventional manner in the art or according to the product instructions. In addition, any methods and materials similar to or equivalent to those described herein can be applied to the present invention.

[0046] In the following examples, the main components of the boron mud are: SiO246.1 wt .%,MgO 21.7 wt.%,Fe2O319.6 wt .%,B2O32.4 wt .%, and the remainder includes CaO, Al2O3, FeO, etc.

[0047] Example 1:

[0048] A process for preparing a carbon-reducing lightweight high-strength aggregate concrete material comprises the following steps:

[0049] (1) Mix the boron mud powder with a concentration of 5 wt .% dilute sulfuric acid at a ratio of 1g:20ml and stir continuously for 3.5 hours. After completion, filter and set aside the obtained extract and solid residue.

[0050] (2) The solid residue of step (1) is mixed with a concentration of 1.5 wt .% water glass at a ratio of 1g:6ml, and then heated to 70℃ and kept warm for 120min. After completion, the obtained solid product is dried, then ground, and passed through a 400-mesh sieve to obtain modified borax powder.

[0051] (3) The extract from step (1) and 30-mesh wood powder were mixed at a ratio of 25 ml:1 g and ultrasonically shaken for 45 minutes. After standing for 10 minutes, sodium hydroxide solution was added dropwise to adjust the pH of the system to 8. The mixture was then heated to 100°C and evaporated to remove moisture from the system to obtain modified wood powder.

[0052] (4) Take the following raw materials in the following proportions: 100 parts by weight of the modified wood flour, 28 parts by weight of modified borax 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-type dicalcium silicate powder, and 4 parts by weight of borax, mix them and stir for 5 minutes, then add 23 parts by weight of clean water and stir for 1 minute before granulation. The obtained granules are dried at 70°C for 1.5 hours, and granules with a particle size between 1 and 2 cm are sieved to obtain lightweight coarse aggregate.

[0053] (5) The lightweight coarse aggregate is placed in a mixture of carbon dioxide and water vapor in a volume ratio of 80%:20% for 2 hours for post-treatment. After completion, saturated lime water is evenly sprayed on the aggregate in a ratio of 1g:2ml, and then placed in a curing box in a closed environment at 60°C for 7.5 hours. After completion, the aggregate is naturally dried for 4 days to obtain the modified lightweight coarse aggregate (such as Figure 1 shown).

[0054] (6) Take the following 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 and stir them 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. Then, mix with the powder and stir for 3 minutes to obtain a concrete material.

[0055] Performance test: The concrete material prepared in this embodiment was poured into a mold and cured for 28 days. The compressive strength of the concrete specimens was then tested according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081-2019). Figure 2 The result is 33.16 MPa.

[0056] Example 2:

[0057] A process for preparing a carbon-reducing lightweight high-strength aggregate concrete material comprises the following steps:

[0058] (1) Mix the borax powder with a concentration of 7 wt .% hydrochloric acid at a ratio of 1g:10ml and stir continuously for 2 hours. After completion, filter and set aside the obtained extract and solid residue.

[0059] (2) The solid residue of step (1) is mixed with a concentration of 2.5 wt .% water glass at a ratio of 1g:5ml, and then heated to 60℃ and kept warm for 150min. After completion, the obtained solid product is dried, then ground, and passed through a 400-mesh sieve to obtain modified borax powder.

[0060] (3) The extract from step (1) and 20-mesh wood powder were mixed at a ratio of 30 ml:1 g and ultrasonically shaken for 60 minutes. After standing for 10 minutes, sodium hydroxide solution was added dropwise to adjust the pH of the system to 7.5. The mixture was then heated to 110°C and evaporated to dryness to remove moisture, thereby obtaining modified wood powder.

[0061] (4) Take the following raw materials in the following proportions: 100 parts by weight of the modified wood flour, 33 parts by weight of modified borax 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 and stir for 5 minutes, then add 25 parts by weight of clean water and stir for 1 minute before granulation. The obtained granules are dried at 65°C for 2 hours, and granules with a particle size between 1 and 2 cm are sieved to obtain lightweight coarse aggregate.

[0062] (5) The lightweight coarse aggregate is placed in a mixture of carbon dioxide and water vapor in a volume percentage of 75%:25% for 3 hours for post-treatment. After completion, saturated lime water is evenly sprayed on the aggregate in a ratio of 1g:3ml, and then placed in a curing box in a closed environment at 50°C for 10 hours. After completion, the aggregate is naturally dried for 4 days to obtain modified lightweight coarse aggregate (such as Figure 3 shown).

[0063] (6) Take the following 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 lightweight coarse aggregate. Mix the above raw materials and stir them evenly to obtain a powder. Then, add 3.5 parts by weight of sodium lignin sulfonate water reducer to 100.8 parts by weight of mixing water and stir evenly. Then, mix with the powder and stir for 3 minutes to obtain a concrete material.

[0064] Performance test: The concrete material prepared in this embodiment was poured into a mold and cured for 28 days. The compressive strength of the concrete specimens was then tested according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081-2019). Figure 4 As shown), the result is 36.48MPa.

[0065] Example 3:

[0066] A process for preparing a carbon-reducing lightweight high-strength aggregate concrete material comprises the following steps:

[0067] (1) Mix the boron mud powder with a concentration of 3 wt .% sulfuric acid at a ratio of 1g:30ml and stir continuously for 4 hours. After completion, filter and set aside the obtained extract and solid residue.

[0068] (2) The solid residue of step (1) is mixed with a concentration of 1.0 wt .% water glass was mixed at a ratio of 1g:8ml and heated to 65°C for 130min. After completion, the solid product was dried and then ground. After passing through a 500-mesh sieve, modified borax powder was obtained.

[0069] (3) The extract from step (1) and 50-mesh wood powder were mixed at a ratio of 20 ml:1 g and ultrasonically shaken for 40 minutes. After standing for 10 minutes, sodium hydroxide solution was added dropwise to adjust the pH of the system to 8. The mixture was then heated to 105°C and evaporated to dryness to remove moisture from the system, thereby obtaining modified wood powder.

[0070] (4) Take the following raw materials in the following proportions: 100 parts by weight of the modified wood flour, 26 parts by weight of modified borax powder, 13 parts by weight of basalt fiber 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 minutes, then add 21 parts by weight of clean water and stir for 1 minute before granulation. The obtained granules are dried at 60°C for 110 minutes, and granules with a particle size between 1 and 2 cm are sieved to obtain lightweight coarse aggregate.

[0071] (5) The lightweight coarse aggregate is placed in a mixture of carbon dioxide and water vapor in a volume percentage of 70%:30% for 4 hours for post-treatment. After completion, saturated lime water is evenly sprayed on the aggregate in a ratio of 1g:2ml, and then placed in a curing box in a closed environment at 70°C for 6 hours. After completion, the aggregate is naturally dried for 4 days to obtain modified lightweight coarse aggregate (such as Figure 5 shown).

[0072] (6) Take the following raw materials in the following proportions: 262 parts by weight of 42.5 parts of 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 and stir them 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. Then, mix with the powder and stir for 3 minutes to obtain a concrete material.

[0073] Performance test: The concrete material prepared in this embodiment was poured into a mold and cured for 28 days. The compressive strength of the concrete specimens was then tested according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081-2019). Figure 6 As shown), the result is 31.67MPa.

[0074] Example 4:

[0075] A process for preparing a carbon-reducing lightweight high-strength aggregate concrete material comprises the following steps:

[0076] (1) Mix the boron mud powder with a concentration of 5 wt .% dilute sulfuric acid at a ratio of 1g:20ml and stir continuously for 3.5 hours. After completion, filter and set aside the obtained extract and solid residue.

[0077] (2) The solid residue of step (1) is mixed with a concentration of 1.5 wt .% water glass at a ratio of 1g:6ml, and then heated to 70℃ and kept warm for 120min. After completion, the obtained solid product is dried, then ground, and passed through a 400-mesh sieve to obtain modified borax powder.

[0078] (3) The extract from step (1) and 30-mesh wood powder were mixed at a ratio of 25 ml:1 g and ultrasonically shaken for 45 minutes. After standing for 10 minutes, sodium hydroxide solution was added dropwise to adjust the pH of the system to 8. The mixture was then heated to 100°C and evaporated to remove moisture from the system to obtain modified wood powder.

[0079] (4) Take the following raw materials in the following proportions: 100 parts by weight of the modified wood flour, 28 parts by weight of modified borax 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-type dicalcium silicate powder, and 4 parts by weight of borax, mix them and stir for 5 minutes, then add 23 parts by weight of clean water and stir for 1 minute before granulation. The obtained granules are dried at 70°C for 1.5 hours, and granules with a particle size between 1 and 2 cm are sieved to obtain lightweight coarse aggregate.

[0080] (5) The lightweight coarse aggregate is mixed with saturated lime water at a ratio of 1g:40ml, and then kept at 60℃ for 7.5 hours. After completion, the obtained aggregate is naturally dried for 4 days to obtain the modified lightweight coarse aggregate (such as Figure 7 shown).

[0081] (6) Take the following 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 and stir them 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. Then, mix with the powder and stir for 3 minutes to obtain a concrete material.

[0082] Performance test: The concrete material prepared in this embodiment was poured into a mold and cured for 28 days. The compressive strength of the concrete specimens was then tested according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081-2019). Figure 8 As shown), the result is 26.33MPa.

[0083] Example 5:

[0084] A process for preparing a carbon-reducing lightweight high-strength aggregate concrete material comprises the following steps:

[0085] (1) Mix the boron mud powder with a concentration of 3 wt .% sulfuric acid at a ratio of 1g:30ml and stir continuously for 4 hours. After completion, filter and set aside the obtained extract and solid residue.

[0086] (2) The solid residue of step (1) is mixed with a concentration of 1.0 wt.% water glass was mixed at a ratio of 1g:8ml and heated to 65°C for 130min. After completion, the solid product was dried and then ground. After passing through a 500-mesh sieve, modified borax powder was obtained.

[0087] (3) The extract from step (1) and 50-mesh wood powder were mixed at a ratio of 20 ml:1 g and ultrasonically shaken for 40 minutes. After standing for 10 minutes, sodium hydroxide solution was added dropwise to adjust the pH of the system to 8. The mixture was then heated to 105°C and evaporated to dryness to remove moisture from the system, thereby obtaining modified wood powder.

[0088] (4) Take the following raw materials in the following proportions: 100 parts by weight of the modified wood flour, 26 parts by weight of modified borax powder, 13 parts by weight of basalt fiber 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 minutes, then add 21 parts by weight of clean water and stir for 1 minute before granulation. The obtained granules are dried at 60°C for 110 minutes, and granules with a particle size between 1 and 2 cm are sieved to obtain lightweight coarse aggregate.

[0089] (5) The lightweight coarse aggregate is placed in a mixture of carbon dioxide and water vapor in a volume ratio of 70%:30% for 4 hours for post-treatment. After completion, the obtained aggregate is naturally dried for 4 days to obtain modified lightweight coarse aggregate (such as Figure 9 shown).

[0090] (6) Take the following raw materials in the following proportions: 262 parts by weight of 42.5 parts of 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 and stir them 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. Then, mix with the powder and stir for 3 minutes to obtain a concrete material.

[0091] Performance test: The concrete material prepared in this embodiment was poured into a mold and cured for 28 days. The compressive strength of the concrete specimens was then tested according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081-2019). Figure 10 As shown), the result is 28.02MPa.

[0092] Example 6:

[0093] A process for preparing a lightweight aggregate concrete material comprises the following steps:

[0094] (1) Crush the waste wood and sieve out particles with a size of 1 to 2 cm to obtain wood aggregate for later use.

[0095] (2) Prepare 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 and stir them evenly to obtain a powder. Then, add 3.5 parts by weight of sodium lignin sulfonate water reducer to 100.8 parts by weight of mixing water and stir evenly. Then, mix with the powder and stir for 3 minutes to obtain a concrete material.

[0096] Performance test: The concrete material prepared in this embodiment was poured into a mold and cured for 28 days. The compressive strength of the concrete specimens was then tested according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081-2019). Figure 11 The result is 23.53 MPa.

[0097] Example 7:

[0098] A process for preparing a carbon-reducing lightweight high-strength aggregate concrete material comprises the following steps:

[0099] (1) Mix the boron mud powder with a concentration of 5 wt .% dilute sulfuric acid at a ratio of 1g:20ml and stir continuously for 3.5 hours. After completion, filter and set aside the obtained extract and solid residue.

[0100] (2) The solid residue of step (1) is mixed with a concentration of 1.5 wt .% water glass at a ratio of 1g:6ml, and then heated to 70℃ and kept warm for 120min. After completion, the obtained solid product is dried, then ground, and passed through a 400-mesh sieve to obtain modified borax powder.

[0101] (3) The extract from step (1) and 30-mesh wood powder were mixed at a ratio of 25 ml:1 g and ultrasonically shaken for 45 minutes. After standing for 10 minutes, sodium hydroxide solution was added dropwise to adjust the pH of the system to 8. The mixture was then heated to 100°C and evaporated to remove moisture from the system to obtain modified wood powder.

[0102] (4) Take the following raw materials in the following proportions: 100 parts by weight of the modified wood flour, 28 parts by weight of modified borax 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 and stir for 5 minutes, then add 23 parts by weight of clean water and stir for 1 minute before granulation. The obtained granules are dried at 70°C for 1.5 hours, and granules with a particle size between 1 and 2 cm are sieved to obtain lightweight coarse aggregate.

[0103] (5) The lightweight coarse aggregate is placed in a mixture of carbon dioxide and water vapor in a volume ratio of 80%:20% for 2 hours for post-treatment. After completion, saturated lime water is evenly sprayed on the aggregate in a ratio of 1g:2ml, and then placed in a curing box in a closed environment at 60°C for 7.5 hours. After completion, the aggregate is naturally dried for 4 days to obtain the modified lightweight coarse aggregate (such as Figure 12 shown).

[0104] (6) Take the following 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 and stir them 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. Then, mix with the powder and stir for 3 minutes to obtain a concrete material.

[0105] Performance test: The concrete material prepared in this embodiment was poured into a mold and cured for 28 days. The compressive strength of the concrete specimens was then tested according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081-2019). Figure 13 As shown), the result is 28.24MPa.

[0106] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still make repairs to the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any repairs, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A process for preparing a carbon-reducing lightweight high-strength aggregate concrete material, characterized in that: The steps include: (1) The borax powder is immersed in an acidic liquid to extract the magnesium element therein, and after completion, the solid-liquid separation is performed to obtain an extract and a solid residue; the solid residue is mixed with water glass and heated and kept warm, and after completion, it is dried and ground to obtain a modified borax powder; wherein: the ratio of the borax powder to the acidic liquid is 1g:10-30ml; the ratio of the solid residue to the water glass is 1g:5-8ml; (2) The extract and wood powder are mixed and then ultrasonically shaken. After the mixture is completed, an alkaline solution is added until the mixture becomes alkaline; then, water in the system is removed to obtain modified wood powder; (3) Mixing the modified wood powder, modified borax powder, chopped fibers, potassium dihydrogen phosphate or ammonium dihydrogen phosphate powder, γ-type dicalcium silicate powder, and retarder, then adding clean water, mixing well, and granulating. After drying, lightweight coarse aggregate is obtained. (4) placing the lightweight coarse aggregate in a mixture of carbon dioxide and water vapor for post-treatment, spraying saturated lime water on the aggregate and then steam curing it; after completion, drying the aggregate to obtain modified lightweight coarse aggregate; (5) The cement binder, expanded perlite fine aggregate, fly ash, the modified lightweight coarse aggregate, water reducer and mixing water are uniformly mixed to obtain concrete material.

2. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (1), the mass fraction of the acidic liquid is 3-7%.

3. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (1), the acidic liquid includes at least one of hydrochloric acid, sulfuric acid, and nitric acid.

4. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (1), the immersion time is 2 to 4 hours.

5. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (1), the mass fraction of the water glass is 1-2.5%.

6. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (1), the heating and heat preservation temperature is 60-70°C and the time is 120-150 minutes.

7. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (1), the fineness of the modified borax powder is 400-500 mesh.

8. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (2), the ratio of the extract to wood powder is 20-30 ml: 1 g.

9. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (2), the fineness of the wood powder is 20-50 mesh.

10. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (2), the ultrasonic oscillation treatment time is not less than 40 minutes.

11. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (2), an alkaline solution is added until the system pH is 7.5-8.

12. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (2), the alkaline solution includes at least one of a sodium hydroxide solution and a potassium hydroxide solution.

13. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (3), the ratio of the modified wood powder, modified borax powder, chopped fibers, potassium dihydrogen phosphate or ammonium dihydrogen phosphate powder, γ-type dicalcium silicate powder, retarder, and clean 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, and 3.5-5 parts by weight: 21-25 parts by weight.

14. The process for preparing the carbon-reduced 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.

15. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (3), the length of the chopped fibers is 2 to 5 mm.

16. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (3), the retarder includes at least one of borax and sodium tripolyphosphate.

17. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (3), the particle size of the lightweight coarse aggregate is 1-2 cm.

18. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (3), the drying temperature is 60-70° C. and the drying time is 1.5-2 hours.

19. The process for preparing the carbon-reduced 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%.

20. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (4), the post-treatment time is 2 to 4 hours.

21. The process for preparing the carbon-reduced 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.

22. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (4), the steaming treatment is carried out at a temperature of 50 to 70° C. for 6 to 10 hours.

23. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to any one of claims 1 to 9, characterized in that: In step (5), the proportions of the cementitious material, expanded perlite fine aggregate, fly ash, the modified lightweight coarse aggregate, and the water reducer are 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; and the mixing water is 0.42-0.46% of the mass of the cement.

24. The process for preparing the carbon-reduced lightweight high-strength aggregate concrete material according to claim 1, characterized in that: In step (5), the water reducer includes at least one of a polycarboxylic acid water reducer, a lignin sulfonate water reducer, a naphthalene water reducer, a melamine water reducer, and an aliphatic water reducer.

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