A hole slag powder admixture concrete and a preparation method thereof

Abstract

The application discloses a hole slag stone powder admixture concrete and a preparation method thereof. The hole slag stone powder admixture concrete comprises the following components in mass fractions: cement, sand, stone, water, copper slag stone powder admixture, water reducing agent and additive. The additive is prepared from calcium oxide, polyacrylamide, wood fiber and boric acid. The preparation method of the hole slag stone powder admixture concrete comprises uniformly mixing the components of the concrete. By adding the additive prepared from calcium oxide, polyacrylamide, wood fiber and boric acid into the concrete, on one hand, the absorption of water in the concrete by the copper slag stone powder can be inhibited, and on the other hand, the obvious dry shrinkage phenomenon caused by the evaporation of water in the hole slag stone powder admixture can be relieved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a slag powder admixture concrete and its preparation method. Background Technology

[0002] Cave slag, also known as rock debris, is the waste rock excavated from caves. With the continuous development of infrastructure construction in my country, natural sand and gravel resources are gradually decreasing. In recent years, in response to the requirements of green engineering construction and to reduce construction costs, the resource utilization of cave slag has been gradually realized. Currently, the resource utilization of cave slag in my country mainly includes filling and backfilling pits, leveling land, raising foundations, and constructing landscape parks. A small portion is also processed into manufactured sand for use in concrete.

[0003] Tractor slag powder refers to particles with a diameter of less than 75 micrometers produced during the manufacturing of manufactured sand. Under magnification, tractor slag powder particles exhibit diverse appearances, with rough surfaces, sharp edges, uneven size distribution, large specific surface area, and high water absorption. Furthermore, because tractor slag powder originates from stone waste, its composition is more complex than ordinary stone powder, containing impurities such as mud powder and weathered rock particles. Therefore, in practical applications, when using tractor slag powder in concrete mixing, the impurities in the powder cause it to absorb a large amount of mixing water, leading to volume expansion. During the drying process, the moisture in the powder evaporates freely, causing shrinkage in the concrete and potentially surface cracking, reducing its workability, mechanical properties, and durability. Therefore, there is still room for improvement in tractor slag powder admixture concrete. Summary of the Invention

[0004] To address the issue of high water absorption in slag powder admixtures, this application provides a slag powder admixture concrete and its preparation method. This application utilizes an admixture prepared from calcium oxide, polyacrylamide, wood fiber, and boric acid to add to the concrete. This admixture inhibits the absorption of water from the slag powder and alleviates the significant drying shrinkage caused by water evaporation from the slag powder admixture.

[0005] Firstly, the technical solution for the slag and stone powder admixture concrete provided in this application is as follows:

[0006] A type of concrete with slag and stone powder admixture comprises the following components in parts by weight: 280-360 parts cement, 620-680 parts sand, 1020-1090 parts stone, 142-158 parts water, 89-102 parts copper slag and stone powder admixture, 8.7-10.3 parts water-reducing agent, and 84.3-90.4 parts admixture;

[0007] The additive is prepared from calcium oxide, polyacrylamide, lignocellulose, and boric acid.

[0008] The preparation method of the admixture includes the following steps:

[0009] 1. Mix and stir the wood fiber, boric acid, and water in a mass ratio of (1-2):1;

[0010] 2. Add polyacrylamide to the solution obtained in step (1), mix, stir, and dry;

[0011] 3. Mix calcium oxide and the product obtained in step (2) and grind them to obtain the additive.

[0012] In the above technical solution, adding the admixture prepared in this application to the copper slag and stone powder admixture concrete can alleviate the concrete shrinkage phenomenon caused by the free evaporation of moisture in the slag and stone powder during the drying process. First, the surface of the wood fiber modified by boric acid is rougher. Then, by adding polyacrylamide, the polyacrylamide forms hydrogen bonds with the hydroxyl groups of the wood fiber in water, producing a strong adsorption effect. When mixed with the copper slag and stone powder admixture, it can strongly adsorb the copper slag and stone powder admixture. Second, the admixture also contains an appropriate amount of calcium oxide, which is a common expansion agent in concrete. When mixed with wood fiber, it can adhere to the rough surface of the wood fiber.

[0013] Adding admixtures to copper slag and stone powder admixture concrete allows the admixtures to tightly adhere to the outer surface of the copper slag and stone powder, reducing the water absorption rate and enabling the cement to hydrate more effectively. The calcium oxide contained within the admixtures significantly fills the micro-cracks caused by the free evaporation of water from the copper slag and stone powder, thus mitigating the drying shrinkage of the concrete. Furthermore, the admixtures form a dense network structure within the copper slag and stone powder concrete, interacting with the admixtures to ensure workability while mitigating the reduction in mechanical properties caused by the copper slag and stone powder adhering to the outer surface of the sand and stone, thus decreasing the contact area between the sand, stone, and cement. This further densifies the concrete, improves the bonding between the various components, and enhances the mechanical strength and durability of the concrete.

[0014] Preferably, the additive comprises the following raw materials in parts by weight: 2.8-3.1 parts calcium oxide, 4.6-5.4 parts polyacrylamide, 18-23 parts lignocellulose, and 3.3-3.9 parts boric acid.

[0015] In the above technical solution, the admixture prepared with the above mass ratio has a better effect on alleviating the drying shrinkage phenomenon of copper slag and stone powder admixture concrete, and improving the mechanical properties and durability of copper slag and stone powder admixture concrete.

[0016] Preferably, the mixing temperature in step (1) is 25-35°C, the stirring rate is 200-220 r / min, and the stirring time is 2-3 h.

[0017] By adopting the above technical solution, boric acid can be fully modified on the outer surface of wood fibers, resulting in a better additive product.

[0018] Preferably, the mixing temperature in step (2) is 50-60°C, the stirring rate is 200-220 r / min, and the stirring time is 1.5-2 h.

[0019] By adopting the above technical solution, the raw materials in the admixture can be fully reacted and mixed, resulting in an admixture product with better effect.

[0020] Preferably, the water-reducing agent comprises the following raw materials in parts by weight: 3-5 parts sodium borate, 0.3-0.8 parts acrylic acid, 2.8-3.4 parts sodium gluconate, and 8.6-9.3 parts calcium lignosulfonate.

[0021] In the above technical solution, the water-reducing agent prepared from sodium borate, acrylic acid, sodium gluconate, and calcium lignosulfonate has the effects of retarding setting and reducing water content. Adding the water-reducing agent to copper slag powder admixture concrete can lock in the moisture in the concrete, delaying the setting time. Combined with the effect of admixtures reducing the water absorption rate of copper slag powder, this allows the copper slag powder admixture concrete to slowly and fully hydrate. Simultaneously, the interaction between the water-reducing agent and admixtures further inhibits the absorption of moisture from the concrete by the copper slag powder, and conversely promotes the absorption of moisture by the copper slag powder admixture during the concrete's setting, evaporation, or the supply of water to promote cement hydration. This further solves the problem that the high water absorption of copper slag powder admixture leads to relatively low internal humidity in the concrete, preventing sufficient cement hydration and causing more micro-cracks, thus affecting concrete quality. This further improves the mechanical strength and durability of copper slag powder admixture concrete.

[0022] Preferably, the water-reducing agent is prepared as follows: sodium borate, acrylic acid, sodium gluconate, calcium lignosulfonate and water are mixed in a mass ratio of (1-2):(1-2), stirred at 50-60°C for 1-2 hours, dried and ground to obtain the water-reducing agent.

[0023] By adopting the above technical solution, the prepared water-reducing agent has better retarding and water-reducing effects.

[0024] Secondly, this application provides a method for preparing slag powder admixture concrete, which adopts the following technical solution:

[0025] A method for preparing slag powder admixture concrete includes the following steps:

[0026] Step 1: Mix the quarry stone powder admixture and additives evenly; separately mix the water-reducing agent and water evenly.

[0027] Step 2: Mix and stir the mixture obtained in Step 1 with cement, sand, stone, and slag powder admixture to obtain copper slag powder admixture concrete.

[0028] Preferably, the steps include:

[0029] Step 1: Mix the slag powder admixture and additives evenly; separately, mix the water-reducing agent with 60% to 70% of the water in the formula evenly.

[0030] Step 2: Mix the mixture obtained in Step 1, cement, sand, stone, slag powder admixture, and the remaining water in the formula, and stir evenly to obtain copper slag powder admixture concrete.

[0031] By adopting the above technical solution, the components of the slag powder admixture concrete can fully react, thereby making the prepared slag powder admixture concrete have better performance.

[0032] In summary, this application includes at least one of the following beneficial technical effects:

[0033] 1. This application involves adding an admixture made of calcium oxide, polyacrylamide, wood fiber, and boric acid to copper slag and stone powder admixture concrete. The admixture tightly adsorbs the copper slag and stone powder, reducing its water absorption rate and allowing for more sufficient hydration of the cement. The calcium oxide it contains significantly fills the micro-cracks caused by the free evaporation of water from the copper slag and stone powder, thus alleviating the drying shrinkage of the concrete. Furthermore, the admixture forms a dense network structure in the copper slag and stone powder concrete, interacting with the admixture. While ensuring the workability of the concrete, it mitigates the reduction in mechanical properties caused by the copper slag and stone powder adhering to the outer surface of the sand and stone, thus decreasing the contact area between the sand and stone and the cement. This further densifies the concrete, improves the bonding between the various components, and enhances the mechanical strength and durability of the concrete.

[0034] 2. This application utilizes a water-reducing agent prepared from sodium borate, acrylic acid, sodium gluconate, and calcium lignosulfonate, which, when added to concrete, provides both retarding and water-reducing effects. Adding this water-reducing agent to copper slag powder admixture concrete locks in moisture, delaying the concrete's setting time. Combined with admixtures that reduce the water absorption rate of copper slag powder, this allows the copper slag powder admixture concrete to hydrate slowly and fully. Simultaneously, the interaction between the water-reducing agent and admixtures further inhibits the absorption of moisture from the concrete by the copper slag powder, and conversely, promotes the absorption of moisture by the copper slag powder admixture during concrete setting, evaporation, or the supply of water to facilitate cement hydration. This further solves the problem that the high water absorption of copper slag powder admixture leads to relatively low internal humidity in the concrete, preventing sufficient cement hydration and resulting in more microcracks that affect concrete quality. This further improves the mechanical strength and durability of the copper slag powder admixture concrete. Detailed Implementation

[0035] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0036] All raw materials used in this application are commercially available.

[0037] Preparation Example 1

[0038] An admixture comprising 2.8g calcium oxide, 4.6g polyacrylamide, 18g lignocellulose, and 3.3g boric acid.

[0039] The preparation method of the admixture includes the following steps:

[0040] Step (1): Mix wood fiber, boric acid and water at a mass ratio of 1:1 at 35°C, with a stirring rate of 220 r / min and a stirring time of 2 h;

[0041] Step (2): Heat to 50℃, mix polyacrylamide into the solution obtained in step (1), stir at a rate of 220 r / min, stir for 1.5 h and then dry;

[0042] Step (3): Mix calcium oxide and the product obtained in step (2) and grind them to obtain the additive.

[0043] Preparation Example 2

[0044] An admixture comprising 3.1g calcium oxide, 5.4g polyacrylamide, 23g lignocellulose, and 3.9g boric acid.

[0045] The preparation method of the admixture includes the following steps:

[0046] Step (1): Mix wood fiber, boric acid and water at a mass ratio of 2:1 at 25°C, at a stirring rate of 200 r / min, and for 3 hours.

[0047] Step (2): Heat to 60℃, mix polyacrylamide into the solution obtained in step (1), stir at a rate of 200 r / min, stir for 2 h and then dry;

[0048] Step (3): Mix calcium oxide and the product obtained in step (2) and grind them to obtain the additive.

[0049] Preparation Example 3

[0050] An admixture, unlike Preparation Example 2, comprises 3.0 g calcium oxide, 5.2 g polyacrylamide, 21 g lignocellulose, and 3.6 g boric acid.

[0051] Preparation Example 4

[0052] A water-reducing agent comprising 3g sodium borate, 0.3g acrylic acid, 2.8g sodium gluconate, and 8.6g calcium lignosulfonate.

[0053] The water-reducing agent is prepared as follows: sodium borate, acrylic acid, sodium gluconate, calcium lignosulfonate and water are mixed in a mass ratio of 1:2, stirred at 50°C for 2 hours, dried and ground to obtain the water-reducing agent.

[0054] Preparation Example 5

[0055] A water-reducing agent comprising 5g sodium borate, 0.8g acrylic acid, 3.4g sodium gluconate, and 9.3g calcium lignosulfonate.

[0056] The water-reducing agent is prepared as follows: sodium borate, acrylic acid, sodium gluconate, calcium lignosulfonate and water are mixed in a mass ratio of 2:1, stirred at 60°C for 1 hour, dried and ground to obtain the water-reducing agent.

[0057] Preparation Example 6

[0058] A water-reducing agent, unlike Preparation Example 5, comprises 4g sodium borate, 0.7g acrylic acid, 3.2g sodium gluconate, and 9g calcium lignosulfonate.

[0059] Preparation Example 7

[0060] A water-reducing agent, unlike Preparation Example 6, does not use sodium borate.

[0061] Preparation Example 8

[0062] A water-reducing agent, unlike Preparation Example 6, does not use acrylic acid.

[0063] Preparation Example 9

[0064] A water-reducing agent, unlike Preparation Example 6, does not use sodium gluconate.

[0065] Comparative Preparation Example 1

[0066] An additive, unlike preparation example 3, does not use calcium oxide.

[0067] Comparative Preparation Example 2

[0068] An additive, unlike Preparation Example 3, does not use polyacrylamide.

[0069] Comparative preparation example 3

[0070] An additive, unlike preparation example 3, does not use boric acid.

[0071] Example 1

[0072] A copper slag and stone powder admixture concrete comprises 280 kg of cement, 620 kg of sand, 1020 kg of stone, 142 kg of water, 89 kg of copper slag and stone powder admixture, 8.7 kg of water-reducing agent, and 84.3 kg of admixture.

[0073] The particle size range of the copper slag stone powder admixture is 30–75 μm.

[0074] The additive was derived from Preparation Example 1.

[0075] The water-reducing agent was derived from Preparation Example 4.

[0076] The preparation method of copper slag and stone powder admixture concrete includes the following steps:

[0077] Step 1: Mix the quarry stone powder admixture and additives evenly; separately mix the water-reducing agent and water evenly;

[0078] Step 2: Mix the mixture obtained in Step 1 with cement, sand, stone, and slag powder admixture, and stir evenly to obtain copper slag powder admixture concrete.

[0079] Example 2

[0080] A copper slag and stone powder admixture concrete, which differs from Example 1, includes 360 kg of cement, 680 kg of sand, 1090 kg of stone, 158 kg of water, 102 kg of copper slag and stone powder admixture, 10.3 kg of water-reducing agent, and 90.4 kg of additives.

[0081] The additive was derived from Preparation Example 2.

[0082] The water-reducing agent was derived from Preparation Example 5.

[0083] The preparation method of copper slag and stone powder admixture concrete includes the following steps:

[0084] Step 1: Mix the slag powder admixture and additives evenly; separately, mix the water-reducing agent with 60% by mass of water in the formula evenly;

[0085] Step 2: Mix the mixture obtained in Step 1, cement, sand, stone, slag powder admixture, and the remaining water in the formula, and stir evenly to obtain copper slag powder admixture concrete.

[0086] Example 3

[0087] A copper slag and stone powder admixture concrete, which differs from Example 1, includes 335 kg of cement, 640 kg of sand, 1070 kg of stone, 145 kg of water, 96 kg of copper slag and stone powder admixture, 9.5 kg of water-reducing agent, and 88.2 kg of additives.

[0088] The additive was derived from Preparation Example 3.

[0089] The water-reducing agent was derived from Preparation Example 6.

[0090] The preparation method of copper slag and stone powder admixture concrete includes the following steps:

[0091] Step 1: Mix the slag powder admixture and additives evenly; separately, mix the water-reducing agent with 70% of the water in the formula evenly.

[0092] Step 2: Mix the mixture obtained in Step 1, cement, sand, stone, slag powder admixture, and the remaining water in the formula, and stir evenly to obtain copper slag powder admixture concrete.

[0093] Example 4

[0094] A copper slag and stone powder admixture concrete, which differs from Example 3 in that the water-reducing agent is derived from Preparation Example 7.

[0095] Example 5

[0096] A copper slag and stone powder admixture concrete, which differs from Example 3 in that the water-reducing agent is derived from Preparation Example 8.

[0097] Example 6

[0098] A copper slag and stone powder admixture concrete, which differs from Example 3 in that the water-reducing agent is derived from Preparation Example 9.

[0099] Example 7

[0100] A copper slag and stone powder admixture concrete differs from Example 3 in that the water-reducing agent is a polycarboxylate type high-performance water-reducing agent.

[0101] Comparative Example 1

[0102] A copper slag and stone powder admixture concrete, which differs from Example 7 in that the admixture is derived from Comparative Preparation Example 1.

[0103] Comparative Example 2

[0104] A copper slag and stone powder admixture concrete, which differs from Example 7 in that the admixture is derived from Comparative Preparation Example 2.

[0105] Comparative Example 3

[0106] A copper slag and stone powder admixture concrete, which differs from Example 7 in that the admixture is derived from Comparative Preparation Example 3.

[0107] Comparative Example 4

[0108] A copper slag and stone powder admixture concrete, which differs from Example 7 in that it does not contain admixtures.

[0109] Copper slag stone powder concrete performance testing

[0110] 1. Slump: The slump (mm) of each of the above embodiments and comparative examples were tested according to GB / T50080-2016.

[0111] 2. Compressive strength: The compressive strength of the standard specimens of the above embodiments and comparative examples was tested according to GB / T50081-2019. The compressive strength (MPa) of the copper slag stone powder concrete was tested after 7 days and 28 days of curing. The test results are shown in Table 1.

[0112] 3. Crack resistance: Crack resistance tests were conducted on the large-volume specimens (30cm*30cm*30cm) of the above embodiments and comparative examples according to GB / T50081-2019. The unit area (m²) measured 24 hours after the copper slag and stone powder concrete was calculated. 2 The number of cracks (strips) was measured, and the test results are shown in Table 1.

[0113] 4. Setting time: Standard specimens of the above embodiments and comparative examples were prepared according to GB / T50080-2016, and the final setting time (min) was recorded. The test results are shown in Table 1.

[0114] 5. Durability: Carbonation resistance tests were conducted on the specimens (100mm*100mm*100mm) of the above embodiments and comparative examples according to GB / T50082-2009. The carbonation depth (mm) of the copper slag stone powder concrete after 28 days of accelerated carbonation was measured. The test results are shown in Table 1.

[0115] Table 1:

[0116]

[0117]

[0118] As can be seen from Table 1, Examples 1-9 have good workability, mechanical strength and durability, especially Examples 1-3, which have excellent workability, mechanical strength and durability.

[0119] Based on the analysis of Example 7 and Comparative Examples 1-4, compared to Example 7, Comparative Examples 1-3 did not use calcium oxide, polyacrylamide, or boric acid as admixtures, while Comparative Example 4 did not add any admixtures. The workability, mechanical strength, and durability of Example 7 were superior to those of Comparative Examples 1-4. This analysis shows that adding the admixture prepared in this application to copper slag and stone powder admixture concrete can indeed tightly adsorb the copper slag and stone powder, reducing the water absorption rate of the copper slag and stone powder, allowing the cement to have sufficient water for hydration. The calcium oxide contained therein can significantly fill the micro-gaps caused by the free evaporation of water from the copper slag and stone powder, thereby alleviating the drying shrinkage of the concrete and improving its workability, mechanical strength, and durability. The admixture prepared from calcium oxide, polyacrylamide, wood fiber, and boric acid has unique properties, and none of these substances can be omitted.

[0120] Based on the analysis of Examples 3 and 4-7, the water-reducing agents in Examples 4-6 did not use sodium borate, acrylic acid, or sodium gluconate, while Example 7 used a polycarboxylate-type high-performance water-reducing agent. The workability, mechanical strength, and durability of Example 3 were superior to those of Example 7, and the workability, mechanical strength, and durability of Example 7 were superior to those of Examples 4-6. Therefore, it can be concluded that only when a water-reducing agent prepared from sodium borate, acrylic acid, sodium gluconate, and calcium lignosulfonate is added to concrete can it have a significant retarding and water-reducing effect. This agent can also interact with admixtures prepared from calcium oxide, polyacrylamide, wood fiber, and boric acid to further inhibit the absorption of water from the concrete by the copper slag powder, and conversely promote the water absorbed by the copper slag admixture to follow the solidification or evaporation of the concrete, or supply water to promote cement hydration, thereby further improving the mechanical strength and durability of the copper slag admixture concrete.

[0121] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A type of concrete with slag and stone powder admixture, characterized in that, The components include the following parts by weight: 280-360 parts cement, 620-680 parts sand, 1020-1090 parts stone, 142-158 parts water, 89-102 parts copper slag stone powder admixture, 8.7-10.3 parts water-reducing agent, and 84.3-90.4 parts additives; The additive comprises the following raw materials in parts by weight: 2.8-3.1 parts calcium oxide, 4.6-5.4 parts polyacrylamide, 18-23 parts lignocellulose, and 3.3-3.9 parts boric acid; The preparation method of the admixture includes the following steps: Mix and stir the wood fiber, boric acid and water in a mass ratio of (1~2):1; Add polyacrylamide to the solution obtained in step (1), mix, stir, and dry; Mix calcium oxide and the product obtained in step (2) and grind them to obtain the additive; The mixing temperature in step (1) is 25~35℃, the stirring rate is 200~220r / min, and the stirring time is 2~3h; The mixing temperature in step (2) is 50~60℃, the stirring rate is 200~220r / min, and the stirring time is 1.5~2h.

2. The slag powder admixture concrete according to claim 1, characterized in that, The water-reducing agent comprises the following raw materials in parts by weight: 3-5 parts sodium borate, 0.3-0.8 parts acrylic acid, 2.8-3.4 parts sodium gluconate, and 8.6-9.3 parts calcium lignosulfonate.

3. The slag powder admixture concrete according to claim 2, characterized in that, The water-reducing agent is prepared as follows: sodium borate, acrylic acid, sodium gluconate, calcium lignosulfonate and water are mixed in a mass ratio of (1~2):(1~2), stirred at 50~60℃ for 1~2 hours, dried and ground to obtain the water-reducing agent.

4. A method for preparing slag powder admixture concrete as described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Mix the quarry stone powder admixture and additives evenly; separately mix the water-reducing agent and water evenly. Step 2: Mix and stir the mixture obtained in Step 1 with cement, sand, stone, and slag powder admixture to obtain copper slag powder admixture concrete.

5. The method for preparing slag powder admixture concrete according to claim 4, characterized in that, Includes the following steps: Step 1: Mix the slag powder admixture and additives evenly; separately, mix the water-reducing agent with 60%~70% water by mass in the formula evenly; Step 2: Mix the mixture obtained in Step 1, cement, sand, stone, slag powder admixture, and the remaining water in the formula, and stir evenly to obtain copper slag powder admixture concrete.

Images