Low-carbon gel material for concrete road as well as preparation method and application of low-carbon gel material

Abstract

The invention belongs to the technical field of resource reutilization, and discloses a low-carbon gel material for a concrete road as well as a preparation method and application of the low-carbon gel material for the concrete road, and the low-carbon gel material for the concrete road is mainly prepared from the following raw materials in parts by mass: 50-65 parts of mineral powder; 15-20 parts of electrolytic aluminum red mud; 10-15 parts of steel slag micro powder; 5-10 parts of waste concrete powder; 1-3 parts of a composite activator; the composite exciting agent is prepared from a Na2SO4 solution, CaSO4, triethanolamine, monoethanolamine and N-methyldiethanolamine. The invention further provides a preparation method of the low-carbon cementing material for the concrete road. The low-carbon cementing material is prepared through the synergistic effect of multiple solid wastes, and resource utilization of the multiple solid wastes is achieved. Through the synergistic effect of gradient alkali excitation and ultrasonic excitation, excitation of solid waste activity is achieved, the low-carbon cementing material is prepared, and the performance of the low-carbon cementing material and the mechanical property and durability of the low-carbon cementing material in concrete are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of resource recycling, and particularly relates to a low-carbon gel material for concrete roads, a preparation method thereof, and an application thereof. Background Art

[0002] Low-carbon cementitious materials have become an important type of cementitious materials that can replace cement in applications. Compared with traditional cementitious materials (such as Portland cement), a large amount of carbon dioxide is released during the production process, while low-carbon cementitious materials mainly use alternative raw materials such as solid wastes, which can significantly reduce carbon dioxide emissions and help reduce the environmental impact of the construction industry; moreover, less energy is usually required during production and use, so energy consumption can be reduced and the energy utilization efficiency of the construction industry can be improved. However, there are still major problems in the development of low-carbon cementitious materials at present. On the one hand, the performance of low-carbon cementitious materials may fluctuate greatly due to differences in the components of different industrial wastes; more importantly, the current technology of low-carbon cementitious materials is not yet mature, and there are still some technical problems to be overcome. For example, there are still major problems in improving the performance of low-carbon cementitious materials in terms of strength, durability, and stability. At present, low-carbon cementitious materials also face problems such as low strength and poor durability when used in concrete road engineering. Summary of the Invention

[0003] Aiming at the problems and deficiencies existing in the prior art, the present invention aims to provide a low-carbon gel material for concrete roads, a preparation method thereof, and an application thereof.

[0004] In order to achieve the object of the present invention, the technical solution adopted by the present invention is as follows:

[0005] The first aspect of the present invention protects a low-carbon cementitious material for concrete roads, which is mainly made of the following raw materials in parts by mass:

[0006] 50 - 65 parts of mineral powder;

[0007] 15 - 20 parts of electrolytic aluminum red mud;

[0008] 10 - 15 parts of steel slag micropowder;

[0009] 5 - 10 parts of waste concrete powder;

[0010] 1 - 3 parts of a composite activator;

[0011] The composite activator is composed of a Na2SO4 solution, CaSO4, triethanolamine, monoethanolamine, and N-methyldiethanolamine.

[0012] Preferably, the mass ratio of Na2SO4 solution, CaSO4, triethanolamine, monoethanolamine, and N-methyldiethanolamine in the composite activator is 1:(1-3):(2-4):(1-3):(1-3).

[0013] Preferably, the concentration of the Na2SO4 solution is 1% - 2%.

[0014] Preferably, the specific surface area of the mineral powder is 400 - 600 m 2 / kg.

[0015] Preferably, the mineral powder is the mineral powder in "Granulated Blast Furnace Slag Powder for Cement, Mortar and Concrete" GB / T 18046-2017.

[0016] Preferably, the specific surface area of the electrolytic aluminum red mud is 350 - 500 m 2 / kg.

[0017] Preferably, the specific surface area of the steel slag powder is 500 - 800 m 2 / kg.

[0018] Preferably, the steel slag is a by-product generated during the steelmaking process, mainly composed of various oxides formed by the oxidation of impurities such as silicon, manganese, phosphorus, and sulfur in pig iron during the smelting process, and salts formed by the reaction of these oxides with solvents. The steel slag powder is a powder obtained by grinding steel slag.

[0019] Preferably, the specific surface area of the waste concrete powder is 300 - 500 m 2 / kg of particles.

[0020] The second aspect of the present invention protects a preparation method of the low-carbon gel material for concrete roads according to any one of the first aspect, comprising the following steps:

[0021] (1) Place the above raw materials in parts by mass and 5 - 10 parts by mass of ammonia water with a concentration of 25% - 28% in a closed ammonia atmosphere, control the air pressure at 0.2 - 0.4 MPa, and start stirring at a speed of 5 - 20 r / min;

[0022] (2) Apply high-frequency ultrasonic waves of 60 - 100 kHz to the materials in step (1) and continuously stir for 2 - 3 h;

[0023] (3) Evacuate the ammonia gas, take out the materials in step (2), and dry them at 80 - 120 °C to obtain the low-carbon gel material.

[0024] The third aspect of the present invention protects the application of the low-carbon gel material according to any one of the first aspect in the preparation of concrete.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) Through the synergistic effect of various solid wastes, the present invention prepares a low-carbon cementitious material, realizing the resource utilization of various solid wastes. Through the synergistic effect of gradient alkali activation and ultrasonic activation, the activation of the solid waste activity is realized, a low-carbon cementitious material is prepared, and the performance of the low-carbon cementitious material and its mechanical properties and durability in concrete are improved.

[0027] (2) Among the raw materials for preparing the low-carbon gel material of the present invention, slag provides silicon-aluminum activity, red mud contains alkali metals (Na / K) which can reduce the dosage of the activator, steel slag powder supplements the iron phase to enhance wear resistance, and waste concrete powder optimizes the particle gradation while providing alkaline substances and hydrated calcium silicate.

[0028] (3) The present invention controls the proportion of each component incorporated in the composite activator to ensure the continuity of the activation effect. In the early stage, sulfates promote the dissolution of calcium ions and accelerate hydration. However, the solubility of calcium sulfate is low and its dissolution is slow, effectively controlling the generation of active substances. At the same time, there are differences in the alkalinity of triethanolamine, monoethanolamine and N-methyldiethanolamine. Triethanolamine has weak alkalinity and mainly acts as a dispersant in the early stage. Monoethanolamine has strong alkalinity and mainly promotes the dissolution of calcium-silicon active substances in materials such as slag and steel slag in the early stage. The alkalinity of N-methyldiethanolamine is in the middle, which can effectively control the reaction alkalinity and at the same time play an emulsifying role to avoid material agglomeration and affect the activation of activity.

[0029] (4) The present invention controls the specific surface area of each raw material to ensure that active substances can be better dissolved during the activation process. If the particle size is too small, the activation effect is poor. If the particle size is too large, the improvement of the activation effect is not obvious and the grinding is difficult.

[0030] (5) During the preparation process of the low-carbon gel material of the present invention, the raw materials are mixed with ammonia water, placed in a sealed ammonia environment and pressurized, mainly to ensure that the materials are fully eroded by the alkaline environment. Under this condition, ultrasonic waves are used to break the pozzolanic particles, increasing the specific surface area and accelerating the contact between alkaline substances and the mineral surface; at the same time, the shock wave generated by the collapse of cavitation bubbles promotes the expansion of lattice defects and the directional stripping of inert components; and the ultrasonic wave generates local high temperature, and the locally high temperature promotes the rapid cooling of the dissolved aluminosilicate to form a highly active amorphous structure.

[0031] (6) During the preparation process of the low-carbon gel material of the present invention, the material is dried at 80-120 °C because under this temperature condition, the material can further promote the activation of activity, is conducive to the continuous progress during the activation of activity, and at the same time removes the residual ammonia. Detailed implementation mode

[0032] To make the objectives, technical solutions and advantages of the present invention more clear and definite, the present invention will be further described in detail below through embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Example 1

[0034] A low-carbon cementitious material for concrete roads is mainly made from the following raw materials in parts by mass:

[0035] Ground granulated blast-furnace slag (specific surface area is 600 m 2 / kg) 50 parts;

[0036] Red mud from electrolytic aluminum (specific surface area is 350 m 2 / kg) 20 parts;

[0037] Steel slag powder (specific surface area is 800 m 2 / kg) 10 parts;

[0038] Waste concrete powder 10 parts;

[0039] Compound activator 1 part;

[0040] The ground granulated blast-furnace slag is the ground granulated blast-furnace slag in "Ground Granulated Blast-Furnace Slag for Use in Cement, Mortar and Concrete" GB / T 18046-2017;

[0041] The steel slag is a by-product generated during the steelmaking process, mainly composed of various oxides formed by the oxidation of impurities such as silicon, manganese, phosphorus, and sulfur in pig iron during the smelting process and salts formed by the reaction of these oxides with solvents. The steel slag powder is the powder obtained by grinding steel slag;

[0042] The waste concrete powder is the powder remaining after the concrete is crushed to prepare recycled aggregates, and the specific surface area of the powder is made to reach 300 m 2 / kg of particles;

[0043] The compound activator is composed of a 2% Na2SO4 solution, CaSO4, triethanolamine, monoethanolamine, and N-methyldiethanolamine mixed evenly in a mass ratio of 1:1:2:1:1.

[0044] The preparation method of the low-carbon cementitious material for concrete roads comprises the following specific steps:

[0045] (1) Add the above raw materials in parts by mass and 10 parts by mass of 25% ammonia water into a closed ammonia stirring tank at the same time, control the air pressure in the closed ammonia tank at 0.4 MPa, and start stirring at a speed of 5 r / min;

[0046] (2) Apply high-frequency ultrasonic waves of 60 kHz to the materials in step (1), continuously stir, and maintain for 3 h;

[0047] (3) Evacuate ammonia gas. After taking out the materials in step (2), dry them at 80 °C to obtain a low-carbon cementitious material.

[0048] Example 2

[0049] A low-carbon cementitious material for concrete roads is mainly made from the following raw materials in parts by mass:

[0050] Ground granulated blast-furnace slag (specific surface area is 400 m 2 / kg) 65 parts;

[0051] Red mud from electrolytic aluminum production (specific surface area is 500 m 2 / kg) 15 parts;

[0052] Steel slag powder (specific surface area is 500 m 2 / kg) 15 parts;

[0053] Waste concrete powder 5 parts;

[0054] Compound activator 3 parts;

[0055] The ground granulated blast-furnace slag is the ground granulated blast-furnace slag in "Ground Granulated Blast-Furnace Slag for Cement, Mortar and Concrete" GB / T 18046-2017;

[0056] The steel slag is a by-product generated during the steelmaking process, mainly composed of various oxides formed by the oxidation of impurities such as silicon, manganese, phosphorus, and sulfur in pig iron during the smelting process and salts formed by the reaction of these oxides with solvents. The steel slag powder is the powder obtained by grinding steel slag;

[0057] The waste concrete powder is the powder obtained by grinding the remaining powder after crushing concrete to prepare recycled aggregates so that its specific surface area reaches 500 m 2 / kg of particles;

[0058] The compound activator is composed of a 1% Na2SO4 solution, CaSO4, triethanolamine, monoethanolamine, and N-methyldiethanolamine mixed evenly in a mass ratio of 1:3:4:3:3.

[0059] The preparation method of the low-carbon cementitious material for concrete roads comprises the following specific steps:

[0060] (1) Add the above raw materials in parts by mass and 5 parts by mass of 28% ammonia water into a closed ammonia gas stirring tank at the same time, control the air pressure in the closed ammonia gas tank at 0.2 MPa, and start stirring at a speed of 20 r / min;

[0061] (2) Apply high-frequency ultrasonic waves of 100 kHz to the materials in step (1), continuously stir, and maintain for 2 h;

[0062] (3) Evacuate ammonia gas. After taking out the materials in step (2), dry them at 120 °C to obtain the low-carbon cementitious material.

[0063] Example 3

[0064] A low-carbon cementitious material for concrete roads is mainly made from the following raw materials in parts by mass:

[0065] Ground granulated blast-furnace slag (specific surface area is 450 m 2 / kg) 60 parts;

[0066] Red mud from electrolytic aluminum (specific surface area is 420 m 2 / kg) 18 parts;

[0067] Steel slag powder (specific surface area is 600 m 2 / kg) 12 parts;

[0068] Waste concrete powder 7 parts;

[0069] Compound activator 2 parts;

[0070] The ground granulated blast-furnace slag is the ground granulated blast-furnace slag in "Ground Granulated Blast-Furnace Slag for Cement, Mortar and Concrete" GB / T 18046-2017;

[0071] The steel slag is a by-product generated during the steelmaking process, mainly composed of various oxides formed by the oxidation of impurities such as silicon, manganese, phosphorus, and sulfur in pig iron during the smelting process and salts formed by the reaction of these oxides with solvents. The steel slag powder is the powder obtained by grinding steel slag;

[0072] The waste concrete powder is the powder remaining after crushing concrete to prepare recycled aggregates, and the specific surface area of the powder after grinding reaches 400 m 2 / kg of particles;

[0073] The compound activator is composed of a Na2SO4 solution with a concentration of 1.4%, CaSO4, triethanolamine, monoethanolamine, and N-methyldiethanolamine mixed evenly in a mass ratio of 1:2:3:2:2.

[0074] The preparation method of the low-carbon cementitious material for concrete roads is as follows:

[0075] (1) Add the above raw materials in parts by mass and 6 parts by mass of 28% ammonia water into a closed ammonia gas stirring tank at the same time, control the air pressure in the closed ammonia gas tank at 0.3 MPa, and start stirring slowly at 10 r / min;

[0076] (2) Apply high-frequency ultrasonic waves with a frequency of 80 kHz to the materials in step (1), continue stirring, and maintain for 2.5 h;

[0077] (3) Evacuate ammonia gas. After taking out the materials in step (2), dry them at 100 °C to obtain a low-carbon cementitious material.

[0078] Application performance testing: Use the low-carbon cementitious materials of Examples 1 to 3 to replace cement to prepare concrete respectively. The concrete mix ratio is 360 kg / m of cementitious material 3 , sand ratio 45%, water-cement ratio 0.45, and the polycarboxylate water reducer is at the recommended dosage (1% of the cementitious material dosage). Test the compressive strength of the concrete in accordance with the provisions of GB / T 50081-2019 "Standard Test Methods for Physical and Mechanical Properties of Concrete", and test the frost resistance (mass loss rate of freeze-thaw cycles), carbonation depth and shrinkage rate of the concrete in accordance with GB / T 50082-2024 "Standard Test Methods for Long-Term and Durability Properties of Concrete".

[0079] For the concrete prepared with the low-carbon gel materials of Examples 1 to 3, its performance is shown in Table 1.

[0080] Table 1 Performance indicators of concrete prepared with low-carbon gel materials of Examples 1 to 3

[0081]

[0082] As can be seen from Table 1, for the concrete prepared with the low-carbon gel materials of Examples 1 to 3, its performance is better than that of the concrete prepared with cement-based materials, with higher compressive strength, lower mass loss rate after 100 freeze-thaw cycles, smaller carbonation depth and 28d shrinkage rate.

[0083] Comparative Example 1

[0084] The difference from Example 3 is that the specific surface area of the mineral powder is 300 m 2 / kg.

[0085] Comparative Example 2

[0086] The difference from Example 3 is that the specific surface area of the electrolytic aluminum red mud is 300 m 2 / kg.

[0087] Comparative Example 3

[0088] The difference from Example 3 is that the specific surface area of the steel slag powder is 400 m 2 / kg.

[0089] Comparative Example 4

[0090] The difference from Example 3 is that the specific surface area of the waste concrete powder is 200 m 2 / kg.

[0091] Concrete was prepared using the low-carbon gel materials of Comparative Examples 1 to 4. The concrete mix ratio was the same as above. The properties of the concrete prepared from the low-carbon gel materials of Comparative Examples 1 to 4 were tested, as shown in Table 2.

[0092] Table 2 Performance indicators of concrete prepared from the low-carbon gel materials of Comparative Examples 1 to 4

[0093]

[0094] As can be seen from Table 2, when the specific surface area of the raw materials used in the preparation of the low-carbon gel material becomes smaller and the particle size becomes larger, the compressive strength, frost resistance, durability, and volume stability of the concrete prepared from the low-carbon cementitious material all decrease.

[0095] Comparative Example 5

[0096] The difference from Example 3 is that monoethanolamine is not incorporated into the composite activator.

[0097] Comparative Example 6

[0098] The difference from Example 3 is that N-methyldiethanolamine is not incorporated into the composite activator.

[0099] Comparative Example 7

[0100] The difference from Example 3 is that the composite activator is composed of a mixture of Na2SO4 solution, CaSO4, triethanolamine, monoethanolamine, and N-methyldiethanolamine in a mass ratio of 1:2:3:5:5.

[0101] Concrete was prepared using the low-carbon gel materials of Comparative Examples 5 to 7. The concrete mix ratio was the same as above. The properties of the concrete prepared from Comparative Examples 5 to 7 were tested, as shown in Table 3.

[0102] Table 3 Performance indicators of concrete prepared from the low-carbon gel materials of Comparative Examples 5 to 7

[0103]

[0104] As can be seen from Table 3, in Comparative Examples 5 to 6, due to the lack of monoethanolamine and N-methyldiethanolamine, the mechanical properties of the concrete prepared from the cementitious material decreased, and the durability such as frost resistance and carbonation resistance also decreased. This is mainly because the lack of the compounding of different alcohol amine components makes it impossible to ensure the stability of the alkalinity of the alkaline activation during the alkaline activation and high-frequency ultrasonic activation processes, resulting in the non-synchronization of the alkaline activation and high-frequency ultrasonic activation and the decrease of the synergistic activation effect, thus causing the performance of the low-carbon cementitious material to decrease. In Comparative Example 7, the excessive dosage of monoethanolamine and N-methyldiethanolamine also causes a decrease in the excitation synergy. Although the mechanical properties decrease slightly, the shrinkage rate increases.

[0105] Comparative Example 8

[0106] The difference from Example 3 is that in step (1) of the preparation method, it is not soaked in ammonia water and not sealed in an ammonia gas environment.

[0107] Prepare concrete using the low-carbon gel material of Comparative Example 8. The concrete mix ratio is the same as above. Detect the performance of the concrete prepared in Comparative Example 8, as shown in Table 4.

[0108] Table 4 Performance indicators of the concrete prepared with the low-carbon gel material of Comparative Example 8

[0109]

[0110] As can be seen from Table 4, the lack of ammonia water infiltration and ammonia gas environment in the preparation method of Comparative Example 8 results in a decline in the mechanical properties and durability of the cementitious material. Because the purpose of mixing the material with ammonia water, placing it in a sealed ammonia gas environment and applying pressure during the preparation process is mainly to ensure that the material is fully eroded by the alkaline environment. Under this condition, ultrasonic waves are used to break volcanic ash particles, increasing the specific surface area and accelerating the contact between alkaline substances and the mineral surface; at the same time, the shock wave generated by the rupture of cavitation bubbles promotes the expansion of lattice defects and the directional stripping of inert components; and the ultrasonic waves generate local high temperatures, which cause the dissolved aluminosilicate to cool rapidly, forming a highly active amorphous structure.

[0111] Comparative Example 9

[0112] The difference from Example 3 is that in step (2) of the preparation method, high-frequency ultrasonic waves are not applied.

[0113] Prepare concrete using the low-carbon gel material of Comparative Example 9. The concrete mix ratio is the same as above. Detect the performance of the concrete prepared in Comparative Example 9, as shown in Table 5.

[0114] Table 5 Performance indicators of the concrete prepared with the low-carbon gel material of Comparative Example 9

[0115]

[0116] As can be seen from Table 5, the lack of high-frequency ultrasonic excitation in Comparative Example 9 results in a decline in the mechanical properties and durability of the concrete prepared from the cementitious material.

[0117] Comparative Example 10

[0118] The difference from Example 3 is that in step (3) of the preparation method, it is air-dried at room temperature.

[0119] Prepare concrete using the low-carbon gel material of Comparative Example 10. The concrete mix ratio is the same as above. Detect the performance of the concrete prepared in Comparative Example 10, as shown in Table 6.

[0120] Table 6 Performance indicators of the concrete prepared with the low-carbon gel material of Comparative Example 10

[0121]

[0122] As can be seen from Table 6, the low-carbon gel material in Comparative Example 10 is dried at room temperature, and the mechanical properties and durability of the gel material decline. This is because under this temperature condition, it can further promote the activation of the material, which is beneficial to the continuous progress of the activation process and simultaneously removes the residual ammonia gas.

Claims

1. A low-carbon cementitious material for concrete roads, characterized in that: It is mainly made of the following raw materials by weight: 50-65 parts of mineral powder; 15-20 parts of electrolytic aluminum red mud; 10-15 parts of steel slag powder; 5-10 parts of waste concrete powder; 1 to 3 parts of composite stimulant; The composite activator consists of Na2SO4 solution, CaSO4, triethanolamine, monoethanolamine and N-methyldiethanolamine.

2. According to the low-carbon cementitious material for concrete roads as described in claim 1, the mass ratio of Na2SO4 solution, CaSO4, triethanolamine, monoethanolamine and N-methyldiethanol in the composite activator is 1:(1-3):(2-4):(1-3):(1-3).

3. The low-carbon gel material according to claim 2, characterized in that: The concentration of the Na2SO4 solution is 1% to 2%.

4. The low-carbon gel material according to claim 1, characterized in that: The specific surface area of ​​the mineral powder is 400-600m 2 / kg.

5. The low-carbon gel material according to claim 1, characterized in that: The specific surface area of ​​the electrolytic aluminum red mud is 350 to 500 m 2 / kg.

6. The low-carbon gel material according to claim 1, characterized in that: The specific surface area of ​​the steel slag powder is 500-800m 2 / kg.

7. The low-carbon gel material according to claim 1, characterized in that: The specific surface area of ​​the waste concrete powder is 300 to 500 m 2 / kg.

8. A method for preparing a low-carbon gel material for concrete roads according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) placing the above raw materials in a sealed ammonia atmosphere at the same time as 5-10 parts by mass of 25%-28% ammonia water, controlling the gas pressure at 0.2-0.4 MPa, and starting stirring at a speed of 5-20 r / min; (2) applying high-frequency ultrasonic waves of 60 to 100 kHz to the material in step (1) and continuously stirring for 2 to 3 hours; (3) evacuating the ammonia gas, taking out the material in step (2), and drying it at 80-120° C. to obtain a low-carbon gelling material.

9. Use of the low-carbon gel material according to any one of claims 1 to 7 in preparing concrete.

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