Method for increasing amount of air-quenched steel slag aggregate in concrete

Abstract

The present application relates to the technical field of steel slag waste recycling, and provides a method for increasing the amount of air-quenched steel slag aggregate in concrete. The method comprises the following steps: (1) weighing calcium lignosulfonate and silicon-containing powder, mixing evenly to obtain a modifier, adding water to the modifier and stirring to dissolve, to obtain a modifying slurry; (2) weighing air-quenched steel slag, pouring the modifying slurry into the air-quenched steel slag, stirring evenly, and placing to dry, to obtain modified air-quenched steel slag; (3) mixing the modified air-quenched steel slag with stone, gravel, yellow sand and cement, adding water, stirring evenly to obtain a mixture, molding the mixture to obtain a green body, and curing the green body. The present method not only increases the amount of modified air-quenched steel slag aggregate in concrete, but also increases the strength of the concrete.

Description

A method for increasing the amount of air-quenched steel slag aggregate in concrete

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on January 25, 2024, with application number 202410101903.2 and application name "A method for increasing the amount of air-quenched steel slag aggregate in concrete", the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of steel slag waste recycling, and in particular to a method for increasing the amount of air-quenched steel slag aggregate used in concrete. Background Art

[0003] Air-quenched steel slag is produced by using high-speed airflow to break liquid steel slag into fine droplets, which are then cooled in a water tank. This granulation process not only creates a spherical shape for the air-quenched steel slag but also eliminates the problem of large lime lumps in the slag being difficult to dissolve. The free CaO content is extremely low, typically below 1%. Therefore, air-quenched steel slag can be used as concrete aggregate.

[0004] However, the spherical surface of air-quenched steel slag is relatively smooth, resulting in poor interlocking properties with other aggregates and poor adhesion to cement when used as an aggregate. In actual applications of air-quenched steel slag as an aggregate, it has been found that when the amount of air-quenched steel slag in concrete exceeds 45%, the resulting green body becomes brittle, has extremely low strength, and is virtually impossible to form, thus significantly limiting its use in concrete.

[0005] Application Contents

[0006] (1) Technical problems solved

[0007] In response to the deficiencies of the prior art, the present application provides a method for increasing the amount of air-quenched steel slag aggregate in concrete, thereby solving the technical problem of poor interlocking properties between air-quenched steel slag and aggregate.

[0008] (2) Technical solution

[0009] To achieve the above objectives, this application is implemented through the following technical solutions:

[0010] A method for increasing the amount of air-quenched steel slag aggregate in concrete comprises the following steps:

[0011] (1) Weighing calcium lignin sulfonate and silicon-containing powder, mixing them evenly to obtain a modifier, adding water to the modifier and stirring to dissolve, thereby obtaining a modified slurry;

[0012] (2) Weighing air-quenched steel slag, pouring the modified slurry into the air-quenched steel slag, stirring evenly, and placing it to dry to obtain modified air-quenched steel slag;

[0013] (3) Mixing the modified air-quenched steel slag with stone, crushed stone, yellow sand and cement, adding water, and stirring evenly to obtain a mixture, shaping the mixture to obtain a green body, and curing the green body.

[0014] Preferably, in step (1), the mass ratio of calcium lignin sulfonate to silicon-containing powder is (1.5-2.5): (1-3).

[0015] Preferably, the silicon-containing powder is selected from at least one of fly ash and silica ash.

[0016] Preferably, the silicon-containing powder is a mixture of silica fume and fly ash.

[0017] Preferably, the mass ratio of the calcium lignin sulfonate, silica fume and fly ash is 2:1:1.

[0018] Preferably, the particle size of the air-quenched steel slag is 0.1 to 2.5 mm.

[0019] Preferably, the modifier accounts for 1-2% of the mass of the air-quenched steel slag.

[0020] Preferably, the mass ratio of the stone, crushed stone, modified air-quenched steel slag, yellow sand and cement is 6: (0-25): (0-25): 12: 7.

[0021] Preferably, in step (3), the water-cement ratio is 0.35 to 0.45.

[0022] Preferably, in step (3), the molding pressure is 20-25 MPa, and the curing parameters include: a curing time of 3-6 hours, a steaming temperature of 50-80° C., and a steaming time of 6-10 hours.

[0023] (3) Beneficial effects

[0024] This application provides a method for increasing the amount of air-quenched steel slag aggregate used in concrete. Compared with the existing technology, it has the following beneficial effects:

[0025] The present application uses a modified slurry prepared from calcium lignin sulfonate, silica fume and / or fly ash to modify the surface of air-quenched steel slag. Calcium lignin sulfonate has adhesive properties when dissolved in water, and the silica fume and / or fly ash in the slurry are bonded to the spherical surface of the air-quenched steel slag. The surface of the air-quenched steel slag after drying is uneven, thereby increasing the bite between it and other aggregates. Moreover, silica fume and fly ash can also react with Ca(OH)2 generated by cement hydration to generate hydraulic cement, thereby improving the strength of concrete, achieving the effect of not only increasing the amount of modified air-quenched steel slag aggregate in concrete, but also improving the strength of concrete. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application are clearly and completely described. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0027] The embodiments of the present application provide a method for increasing the amount of air-quenched steel slag aggregate in concrete, thereby solving the technical problem of poor bite between air-quenched steel slag and aggregate, and increasing the amount of modified air-quenched steel slag aggregate in concrete and the strength of concrete.

[0028] The technical solution in the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:

[0029] Air-quenched steel slag particles are spherical and have a relatively smooth surface. Their interlocking properties with other aggregates and their bonding with cement are poor. When their use, after replacing some crushed stone, reaches 45%, the product exhibits extremely low strength and brittleness after demolding.

[0030] In order to solve the above technical problems, the present application provides a method for increasing the amount of air-quenched steel slag aggregate in concrete, comprising the following steps:

[0031] (1) Weighing calcium lignin sulfonate and silicon-containing powder, mixing them evenly to obtain a modifier, adding water to the modifier and stirring to dissolve, thereby obtaining a modified slurry;

[0032] (2) Weighing air-quenched steel slag, pouring the modified slurry into the air-quenched steel slag, stirring evenly, and placing it to dry to obtain modified air-quenched steel slag;

[0033] (3) Mixing the modified air-quenched steel slag with stone, crushed stone, yellow sand and cement, adding water, and stirring evenly to obtain a mixture, shaping the mixture to obtain a green body, and curing the green body.

[0034] In the step (1), the mass ratio of calcium lignin sulfonate to silicon-containing powder is (1.5-2.5): (1-3).

[0035] The silicon-containing powder is selected from at least one of fly ash and silica fume. Calcium lignin sulfonate, when dissolved in water, exhibits adhesive properties, bonding the silica fume and / or fly ash in the slurry to the spherical surface of the air-quenched steel slag. The resulting uneven surface of the dried air-quenched steel slag enhances its interlocking properties with other aggregates. Furthermore, the silica fume and fly ash react with Ca(OH)2 generated by cement hydration to form a hydraulic cement, thereby increasing the strength of concrete. This not only increases the amount of modified air-quenched steel slag aggregate used in concrete, but also improves concrete strength.

[0036] The silicon-containing powder is a mixture of silica fume and fly ash.

[0037] The mass ratio of the calcium lignin sulfonate, silica fume and fly ash is 2:1:1.

[0038] The particle size of the air-quenched steel slag is 0.1-2.5 mm.

[0039] The modifier accounts for 1-2% of the mass of the air-quenched steel slag. For example, the modifier accounts for 1.5% of the mass of the air-quenched steel slag.

[0040] The mass ratio of the stone, crushed stone, modified air-quenched steel slag, yellow sand and cement is 6: (0-25): (0-25): 12: 7. In step (3), the water-cement ratio is 0.35-0.45. For example, if all the crushed stone is replaced by modified air-quenched steel slag, the mass ratio of the stone, modified air-quenched steel slag, yellow sand and cement is 6: 25: 12: 7, and the water-cement ratio is 0.4.

[0041] In step (3), the green body is poured into a press mold, press-formed, and then allowed to rest for a period of time, then steam-cured for a period of time, and finally cured in a curing box for 28 days. The molding pressure is 20-25 MPa, the resting time is 3-6 hours, the steam curing temperature is 50-80°C, and the steam curing time is 6-10 hours. For example, the molding pressure is 22 MPa, the resting time is 4 hours, the steam curing temperature is 60°C, and the steam curing time is 8 hours.

[0042] In order to better understand the above technical solution, the above technical solution will be described in detail with reference to specific implementation methods below.

[0043] Example 1

[0044] This embodiment provides a method for increasing the amount of air-quenched steel slag aggregate in concrete, comprising the following steps:

[0045] (1) Weigh 100 g of calcium lignin sulfonate, 50 g of fly ash, and 50 g of silica fume, mix them evenly, add water and stir to dissolve them to obtain a modified slurry.

[0046] (2) Weigh 20 kg of air-quenched steel slag with a particle size of 0.1 to 2.5 mm, pour the modified slurry into the slag, stir evenly, and place it to dry to obtain modified air-quenched steel slag.

[0047] (3) The modified air-quenched steel slag was mixed with 6 kg of stone, 5 kg of crushed stone, 12 kg of yellow sand, and 7 kg of cement. 2.8 kg of water was added and stirred evenly to obtain a mixture. The mixture was poured into the press mold in batches of 4 kg each time. After forming at a pressure of 22 MPa, the green body was first cured for 4 h, then steam-cured at 60°C for 8 h, and finally cured in a curing box for 28 days.

[0048] Example 2

[0049] Weigh 112.5 g of calcium lignin sulfonate, 56.25 g of fly ash, and 56.25 g of silica fume, mix them evenly, add water and stir to dissolve them to obtain a modified slurry.

[0050] Weigh 22.5 kg of air-quenched steel slag with a particle size of 0.1 to 2.5 mm, pour the modified slurry into the slag, stir evenly, and place it to dry to obtain modified air-quenched steel slag.

[0051] Modified air-quenched steel slag was mixed with 6kg of stone, 2.5kg of crushed stone, 12kg of yellow sand, and 7kg of cement. 2.8kg of water was added and stirred thoroughly. The resulting mixture was poured into the press mold in portions of 4kg each. After forming at a pressure of 22MPa, the green body was first cured for 4 hours, then steamed at 60°C for 8 hours, and finally cured in a curing chamber for 28 days. (1%, 45%)

[0052] Example 3

[0053] Weigh 125 g of calcium lignin sulfonate, 62.5 g of fly ash, and 62.5 g of silica fume, mix them evenly, add water and stir to dissolve them to obtain a modified slurry.

[0054] Weigh 25 kg of air-quenched steel slag with a particle size of 0.1 to 2.5 mm, pour the modified slurry into the slag, stir evenly, and place it to dry to obtain modified air-quenched steel slag.

[0055] Modified air-quenched steel slag was mixed with 6kg of gravel, 12kg of yellow sand, and 7kg of cement. 2.8kg of water was added and stirred thoroughly. The resulting mixture was poured into the press mold in portions of 4kg each. After forming at a pressure of 22MPa, the green body was first cured for 4 hours, then steam-cured at 60°C for 8 hours, and finally cured in a curing chamber for 28 days. (1%, 50%)

[0056] Example 4

[0057] The difference between this embodiment and embodiment 2 is that the ratios of calcium lignin sulfonate, fly ash and silica fume are different, as shown in Table 1. The rest are the same as embodiment 2.

[0058] Example 5

[0059] The difference between this embodiment and embodiment 2 is that the ratios of calcium lignin sulfonate, fly ash and silica fume are different, as shown in Table 1. The rest are the same as embodiment 2.

[0060] Example 6

[0061] The difference between this embodiment and embodiment 3 is that the amount of the modifier added is different, see Table 1 for details, and the rest is the same as embodiment 3.

[0062] Example 7

[0063] The difference between this embodiment and embodiment 3 is that the amount of the modifier added is different, see Table 1 for details, and the rest is the same as embodiment 3.

[0064] Example 8

[0065] The difference between this embodiment and embodiment 3 is that the modifier components include calcium lignin sulfonate and fly ash, but do not include silica fume. Other components are the same as those in embodiment 3.

[0066] Example 9

[0067] The difference between this embodiment and embodiment 3 is that the modifier components include calcium lignin sulfonate and silica fume, but do not include fly ash. Other components are the same as those in embodiment 3.

[0068] Comparative Example 1

[0069] The difference between this comparative example and Example 1 is that the air-quenched steel slag aggregate is not modified, and the rest is the same as Example 1.

[0070] Comparative Example 2

[0071] The difference between this comparative example and Example 2 is that the air-quenched steel slag aggregate is not modified, and the rest is the same as Example 2.

[0072] Comparative Example 3

[0073] The difference between this comparative example and Example 2 is that the ratios of calcium lignin sulfonate, fly ash and silica fume are different, and the other contents are the same as those in Example 2.

[0074] Comparative Example 4

[0075] The difference between this comparative example and Example 3 is that the modifier component does not include calcium lignin sulfonate, and the other components are the same as Example 3.

[0076] Comparative Example 5

[0077] The difference between this comparative example and Example 3 is that the modifier component does not include fly ash and silica fume, and the rest is the same as Example 3.

[0078] Table 1: Formulas of components and performance test results of Examples 1-9 and Comparative Examples 1-5

[0079] As shown in Table 1, in Comparative Examples 1 and 2, concrete samples were prepared using unmodified air-quenched steel slag aggregate at a dosage of 40%, and the compressive strength of the samples was 38.92 MPa. At a dosage of 45%, the sample body broke after demolding, and the compressive strength dropped sharply, indicating that a 45% addition amount is already the limit for preparing concrete samples using unmodified air-quenched steel slag aggregate. In contrast, in Example 3, concrete samples were prepared using modified air-quenched steel slag aggregate at a dosage of 50%, and the compressive strength of the sample was 43.27 MPa, indicating that modified air-quenched steel slag not only increases the dosage of air-quenched steel slag aggregate in concrete, but also improves concrete strength.

[0080] In Comparative Example 3, the components of the modifier include calcium lignin sulfonate and silicon-containing powder in a mass ratio of 1:2. The prepared concrete sample body is fragile after demolding. The mass ratios of calcium lignin sulfonate and silicon-containing powder in the modifiers of Examples 2, 4 and 5 are 2:2, 1.5:1 and 2.5:3, respectively. The compressive strengths of the prepared concrete samples are 41.96 MPa, 41.13 MPa and 40.87 MPa, respectively. It can be seen that the mass ratio of the modifier components calcium lignin sulfonate and silicon-containing powder affects the performance of the modified air-quenched steel slag. When the mass ratio of calcium lignin sulfonate and silicon-containing powder is (1.5-2.5): (1-3), the modified air-quenched steel slag is modified, the modified air-quenched steel slag aggregate is used in a large amount in concrete, and the prepared concrete sample has high compressive strength.

[0081] In Examples 3, 6, and 7, the addition amounts of the modifiers are different, indicating that the compressive strength of the concrete specimens first increases and then decreases with the increase in the addition amount of the modifier. When the addition amount of the modifier is 1%, the highest compressive strength is 43.27 MPa.

[0082] In Comparative Example 4, the modifier does not include calcium lignin sulfonate, and the modifier of Comparative Example 5 does not include silicon-containing powder. Concrete samples are prepared using modified air-quenched steel slag aggregate. The sample bodies are all broken after demolding, while the compressive strength of Example 3 reaches 43.27 MPa, indicating that the silicon-containing powder and calcium lignin sulfonate have a synergistic effect in improving the compressive strength of concrete.

[0083] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0084] The above embodiments are intended only to illustrate the technical solutions of the present application, not to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some of the technical features therein with equivalents. Such modifications or replacements do not deviate from the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application. Anything not described in detail in this application is well known to those skilled in the art.

Claims

1. A method for increasing the dosage of air-cooled steel slag aggregate in concrete, characterized in that, It includes the following steps: (1) Weigh calcium lignosulfonate and silicon-containing powder, mix them evenly to obtain a modifier, and add water to the modifier and stir to dissolve it to obtain a modified slurry; (2) Weigh air-cooled steel slag, pour the modified slurry into the air-cooled steel slag and stir evenly, and leave it to dry to obtain modified air-cooled steel slag; (3) Mix the modified air-cooled steel slag with stones, crushed stones, yellow sand and cement, add water, stir evenly to obtain a mixture, form the mixture into a green body, and cure the green body.

2. The method for increasing the dosage of air-cooled steel slag aggregate in concrete according to claim 1, wherein, In the step (1), the mass ratio of calcium lignosulfonate to silicon-containing powder is (1.5-2.5):(1-3).

3. The method for increasing the dosage of air-cooled steel slag aggregate in concrete according to claim 1 or 2, characterized in that, The silicon-containing powder is selected from at least one of fly ash or silica fume.

4. The method for increasing the dosage of air-cooled steel slag aggregate in concrete according to claim 3, characterized in that The silicon-containing powder is a mixture of silica fume and fly ash.

5. The method for increasing the dosage of air-cooled steel slag aggregate in concrete according to claim 4, characterized in that The mass ratio of calcium lignosulfonate, silica fume and fly ash is 2:1:

1.

6. The method for increasing the dosage of air-cooled steel slag aggregate in concrete according to claim 1, characterized in that, 7. The method for increasing the dosage of air-cooled steel slag aggregate in concrete according to claim 1, characterized in that, The particle size of the air-cooled steel slag is 0.1-2.5 mm.

8. The method for increasing the dosage of air-cooled steel slag aggregate in concrete according to claim 1, characterized in that, The modifier accounts for 1-2% of the mass of the air-cooled steel slag.

9. The method for increasing the dosage of air-cooled steel slag aggregate in concrete according to claim 1, characterized in that, The mass ratio of the stones, crushed stones, modified air-cooled steel slag, yellow sand and cement is 6:(0-25):(0-25):12:

7.

10. The method for increasing the dosage of air-cooled steel slag aggregate in concrete according to claim 1, characterized in that, In the step (3), the water-cement ratio is 0.35-0.

45. In the step (3), the forming pressure is 20-25 MPa, and the curing parameters include: static curing time of 3-6 h, steam curing temperature of 50-80 °C, and steam curing time of 6-10 h.

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