Concrete containing granite machine-made sand and preparation method thereof
By modifying stone powder, fiber, and fine aggregate, the problems of bulk density and workability of granite manufactured sand concrete were solved, the compressive strength and fluidity were improved, a stable three-dimensional network structure was formed, and the particle bonding strength was enhanced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-03-13
AI Technical Summary
The presence of numerous needle-like and flaky particles in manufactured granite sand leads to a decrease in bulk density and compressive strength. Furthermore, the high adsorption capacity of stone powder for water-reducing agents results in poor workability and uneven structure in concrete.
Modified stone powder, modified fiber, and modified fine aggregate are used to modify granite manufactured sand with epoxy resin and silane coupling agent to form a smooth resin film and three-dimensional network structure, which improves particle bonding strength and concrete workability. High water-absorbing resin is added to disperse stone powder and improve fluidity.
It improves the bulk density and compressive strength of concrete, enhances workability, and strengthens the compressive strength and fluidity of concrete.
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Figure BDA0005712704470000091
Abstract
Description
Technical Field
[0001] This application relates to the field of concrete, and more specifically, to a type of concrete containing manufactured granite sand and a method for preparing the same. Background Technology
[0002] Granite is a siliceous rock with high strength. It is formed by the slow cooling and crystallization of minerals such as quartz, feldspar, and mica deep underground. Its mineral composition is mainly composed of quartz, potassium feldspar, and plagioclase. The high strength of granite makes it difficult to break. Granite manufactured sand contains many needle-like and flaky particles, which leads to a decrease in bulk density and compressive strength. In addition, a large amount of stone powder is generated during the preparation of granite manufactured sand. The stone powder has a large adsorption capacity for water-reducing agents, resulting in poor workability of the prepared concrete, uneven concrete structure, and further reduction in compressive strength.
[0003] Therefore, there is an urgent need to provide a concrete containing granite manufactured sand, which has excellent bulk density and workability, and improves the compressive strength of the concrete. Summary of the Invention
[0004] To increase the compressive strength of concrete containing granite manufactured sand, this application provides a concrete containing granite manufactured sand and a method for preparing the same.
[0005] In the first aspect, the concrete containing granite manufactured sand provided in this application adopts the following technical solution: A type of concrete containing manufactured granite sand comprises the following raw materials in parts by weight: 18-22 parts cement, 6-9 parts modified stone powder, 8-10 parts modified fiber, 30-32 parts modified fine aggregate, 40-45 parts coarse aggregate, 0.5-0.7 parts water-reducing agent, and 15-20 parts water; the modified fine aggregate comprises manufactured granite sand, epoxy resin, and silane coupling agent in a mass ratio of 100:5-8:0.8-1; the preparation method of the modified fine aggregate includes the following steps: (1) Add the silane coupling agent to an ethanol-water solution, add acetic acid dropwise to adjust the pH to 4-5, stir for 30-40 min, and obtain the activated silane coupling agent. (2) At 60-80℃, granite manufactured sand and epoxy resin are mixed evenly to obtain composite manufactured sand; (3) Add the composite manufactured sand to the activated silane coupling agent, stir evenly, and dry to obtain modified fine aggregate.
[0006] By adopting the above technical solution, epoxy resin can uniformly cover the tips and edges of the needle-like particles of granite manufactured sand at high temperature, forming a smooth resin film, improving particle morphology, increasing packing density, and the highly flexible resin film can absorb interfacial stress, reduce the interfacial peeling force caused by the difference in elastic modulus between cement paste and manufactured sand, and increase the bonding strength between manufactured sand and cement. The silanol groups at one end of the activated silane coupling agent condense with the hydroxyl groups of the resin film to form silicon-oxygen-carbon bonds, and the active groups such as amino and epoxy groups at the other end combine with the cement hydration product CSH gel, further increasing the interfacial bonding strength, increasing the packing density, and thus improving the compressive strength of concrete. In addition, after modification by epoxy resin and silane coupling agent, the surface polarity of the needle-like particles of manufactured sand is increased, improving the wettability with cement paste, reducing the friction between particles and cement paste, coarse aggregate and other components, increasing the workability of concrete, and improving its compressive strength.
[0007] Modified fibers can form a three-dimensional network structure in concrete, hindering the migration of water molecules inside the concrete, preventing water evaporation and loss, and improving the workability of concrete. In addition, the three-dimensional network structure formed by modified fibers can evenly distribute concentrated stress, avoiding local overload of concrete. Moreover, the three-dimensional network structure can prevent the propagation and penetration of microcracks through bridging, preventing the collapse of the concrete load-bearing skeleton, thereby increasing the compressive strength of concrete. Modified stone powder disperses stone powder into gel-stone powder single particles, avoiding stone powder agglomeration that leads to viscous paste, improving the fluidity of concrete, and further improving its compressive strength.
[0008] Optionally, the raw materials for the modified fiber include polypropylene fiber, carboxymethyl cellulose, polyvinyl alcohol, and silane coupling agent in a mass ratio of 1-3:1-2:1-2:0.5-0.8.
[0009] Optionally, the method for preparing the modified fiber includes the following steps: (1) Add carboxymethyl cellulose, sodium dodecyl sulfonate and polypropylene fiber to deionized water, stir evenly, keep warm at 80-90℃ for 2-3 hours, and dry to obtain pretreated polypropylene fiber. (2) Add polyvinyl alcohol and silane coupling agent to deionized water, stir evenly, add sodium hydroxide, adjust pH to 9-10, and obtain a mixture. (3) Add the pretreated polypropylene fiber to the mixture, raise the temperature to 50-60℃, soak for 1-2 hours, cool, filter, wash and dry to obtain the modified fiber.
[0010] By adopting the above technical solution, sodium dodecyl sulfonate contains hydrophobic dodecyl chains and hydrophilic sulfonic acid groups. The hydrophobic groups bind to the polypropylene fibers, and the outer sulfonic acid groups increase the number of polar groups on the fiber surface. The repulsive effect of these groups improves the fiber's dispersibility. Carboxymethyl cellulose molecular chains contain a large number of carboxyl and hydroxyl groups, which can bind to the polar groups on the surface of the polypropylene fibers through hydrogen bonds and intermolecular forces, forming a continuous polar coating. The hydroxyl groups of polyvinyl alcohol form hydrogen bonds with the hydroxyl and carboxyl groups of carboxymethyl cellulose, encapsulating the polypropylene fibers. Furthermore, the silane coupling agent undergoes hydrolysis to generate silanol groups, which can form hydrogen bonds or condensation reactions with the hydroxyl groups of polyvinyl alcohol to generate silicon-oxygen-carbon bonds. The process promotes cross-linking between polyvinyl alcohol (PVA) and silane molecules. The silanol groups of silane undergo a condensation reaction with the hydroxyl groups of carboxymethyl cellulose (CMC), increasing the bonding strength between PVA and CMC. The high polarity of PVA and silane greatly improves the wettability of polypropylene fibers, increases the adhesion between polypropylene fibers and cementitious matrix materials, and improves the packing density and compressive strength of concrete. Furthermore, the continuous protective film formed by the CMC-PVA-silane composite coating can fill and cover the micro-scratches and burrs on the surface of polypropylene fibers, preventing stress concentration at weak points and resulting in localized breakage when the fibers are under stress. This increases the tensile properties of the fibers and thus improves the compressive strength of concrete.
[0011] Optionally, the length of the polypropylene fiber is 6-12 mm.
[0012] By adopting the above technical solution, short fibers of this length can fully fill the gaps in concrete, increase the packing density, and form a stable three-dimensional network structure, uniformly dispersing internal stress and improving the compressive strength of concrete.
[0013] Optionally, the method for preparing the modified stone powder includes the following steps: (1) Add super absorbent resin to water and stir for 30-40 minutes to obtain pretreated super absorbent resin; (2) During the stirring process, granite powder is added to the pretreated superabsorbent resin, stirred evenly, fly ash is added, stirred evenly, dried, crushed, and sieved to obtain modified stone powder. The mass ratio of the granite powder, fly ash, and superabsorbent resin is 8-10:1-3:2-3.
[0014] Optionally, the superabsorbent resin is selected from at least one of sodium polyacrylate and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer.
[0015] By adopting the above technical solution, superabsorbent resin is mixed with water to form a gel. The gel combines with stone powder through electrostatic adsorption, dispersing the agglomerated stone powder particles into gel-stone powder single particles, avoiding stone powder agglomeration and improving the fluidity of concrete. Fly ash contains a large number of glass microspheres, which fill the spaces between gel-stone powder particles, reducing the frictional resistance of single particles, increasing the fluidity of stone powder, and improving the workability of concrete.
[0016] Optionally, the coarse aggregate is crushed stone.
[0017] Optionally, the water-reducing agent is a polycarboxylate-based high-performance water-reducing agent.
[0018] Secondly, this application provides a method for preparing concrete containing granite manufactured sand, using the following technical solution: A method for preparing concrete containing manufactured granite sand includes the following steps: Modified fibers and water-reducing agents are added to water and mixed evenly to obtain a mixed solution; cement, modified stone powder, modified fine aggregate and coarse aggregate are mixed evenly to obtain a mixed powder; the mixed solution is slowly poured into the mixed powder being stirred and mixed evenly to obtain concrete.
[0019] In summary, this application has the following beneficial effects: 1. This application preferably uses epoxy resin and silane coupling agent to modify granite manufactured sand, which improves the packing density of particles and cement paste, and further improves its compressive strength; by adding modified fibers, the fibers form a uniform random support system inside the mortar, preventing the propagation of concrete cracks; by using superabsorbent resin to improve the agglomeration of granite powder, the workability of concrete is improved; the combined use of modified fine aggregate, modified fibers and modified stone powder increases the workability and packing density of concrete, and greatly improves its compressive strength.
[0020] 2. This application uses epoxy resin to coat granite manufactured sand, which improves its needle-like particle morphology. The continuous flexible resin film can absorb interfacial stress, improve the bonding between manufactured sand and cement, and modify the resin film with silane coupling agent to increase the surface polarity of the resin film, reduce the friction between particles and between particles and other components, increase the workability of concrete, and thus improve the compressive strength of concrete.
[0021] 3. This application uses carboxymethyl cellulose and polyvinyl alcohol to prepare modified fibers through polar layer-by-layer coating, constructing a carboxymethyl cellulose-polyvinyl alcohol-silane composite coating to encapsulate polypropylene fibers, thereby improving their surface defects, increasing the tensile properties of the fibers, and improving the compressive strength of concrete. Detailed Implementation
[0022] The following embodiments provide a further detailed description of this application.
[0023] Preparation example of modified fine aggregate The silane coupling agent was purchased from Nanjing Lianxi Chemical Co., Ltd., model KH550; the acetic acid was purchased from Shandong Zhengxing New Material Co., Ltd., with a purity of 99%; the manufactured granite sand was purchased from Hebei Jiubao Building Materials Co., Ltd., with a particle size of 2-4mm; and the epoxy resin was purchased from Jinan Jingsheng Chemical Co., Ltd., model E-44.
[0024] Preparation Example 1 (1) Add 1g of silane coupling agent to 50g of ethanol-water (mass ratio 1:1) solution, add acetic acid dropwise to adjust pH to 5, stir for 40min to obtain activated silane coupling agent; (2) At 80℃, 100g of granite manufactured sand and 8g of epoxy resin were stirred evenly to obtain composite manufactured sand. (3) Add the composite manufactured sand obtained in step (2) to the activated silane coupling agent obtained in step (1), stir evenly, and dry at 80°C for 18 hours to obtain modified fine aggregate.
[0025] Preparation Example 2 (1) Add 0.8g of silane coupling agent to 50g of ethanol-water (mass ratio 1:1) solution, add acetic acid dropwise to adjust pH to 4, stir for 30min to obtain activated silane coupling agent; (2) At 60℃, 100g of granite manufactured sand and 5g of epoxy resin were stirred evenly to obtain composite manufactured sand. (3) Add the composite manufactured sand obtained in step (2) to the activated silane coupling agent obtained in step (1), stir evenly, and dry at 80°C for 18 hours to obtain modified fine aggregate.
[0026] Preparation Example 3 The difference from Preparation Example 1 is that no epoxy resin was added. The specific preparation method is as follows: (1) Add 1g of silane coupling agent to 50g of ethanol-water (mass ratio 1:1) solution, add acetic acid dropwise to adjust pH to 5, stir for 40min to obtain activated silane coupling agent; (2) Add 100g of granite manufactured sand to the activated silane coupling agent obtained in step (1), stir evenly, and dry at 80℃ for 18h to obtain modified fine aggregate.
[0027] Preparation Example 4 The difference from Preparation Example 1 is that no silane coupling agent was added. The specific preparation method is as follows: Modified fine aggregate was prepared by mixing 100g of granite manufactured sand and 8g of epoxy resin at 80℃.
[0028] Example of modified fiber preparation The silane coupling agent was purchased from Nanjing Liangui Chemical Co., Ltd., model KH550; the carboxymethyl cellulose was purchased from Hebei Chuangshou Biotechnology Co., Ltd., product number 900-432-4; the polypropylene fiber was purchased from Hubei Kewode Chemical Co., Ltd., with lengths of 3mm, 6mm, and 12mm; and the polyvinyl alcohol was purchased from Hubei Qifei Pharmaceutical Chemical Co., Ltd., product number QF1958.
[0029] Preparation Example 1 (1) Add 2g of carboxymethyl cellulose, 1g of sodium dodecyl sulfonate and 3g of polypropylene fiber with a length of 12mm to 20g of deionized water, stir evenly, keep warm at 90℃ for 3h, and dry to obtain pretreated polypropylene fiber. (2) Add 2g of polyvinyl alcohol and 0.8g of silane coupling agent to 10g of deionized water, stir evenly, add sodium hydroxide, adjust the pH to 10, and obtain a mixed solution. (3) Add the pretreated polypropylene fiber obtained in step (1) to the mixture obtained in step (2), raise the temperature to 60°C, soak for 2 hours, cool, filter, wash, and dry at 60°C for 12 hours to obtain modified fiber.
[0030] Preparation Example 2 (1) Add 1g of carboxymethyl cellulose, 1g of sodium dodecyl sulfonate and 1g of polypropylene fiber with a length of 6mm to 15g of deionized water, stir evenly, keep warm at 80℃ for 2h, and dry to obtain pretreated polypropylene fiber. (2) Add 1g of polyvinyl alcohol and 0.5g of silane coupling agent to 10g of deionized water, stir evenly, add sodium hydroxide, adjust the pH to 9, and obtain a mixed solution. (3) Add the pretreated polypropylene fiber obtained in step (1) to the mixture obtained in step (2), raise the temperature to 50°C, soak for 1 hour, cool, filter, wash, and dry at 60°C for 12 hours to obtain modified fiber.
[0031] Preparation Example 3 The difference from Preparation Example 1 is that carboxymethyl cellulose was not added. The specific preparation method is as follows: (1) Add 4g of polyvinyl alcohol and 0.8g of silane coupling agent to 20g of deionized water, stir evenly, add sodium hydroxide, adjust the pH to 10, and obtain a mixed solution. (2) Add polypropylene fiber to the mixture obtained in step (1), raise the temperature to 60°C, soak for 2 hours, cool, filter, wash, and dry at 60°C for 12 hours to obtain modified fiber.
[0032] Preparation Example 4 The difference from Preparation Example 1 is that polyvinyl alcohol was not added. The specific preparation method is as follows: (1) Add 4g of carboxymethyl cellulose, 1g of sodium dodecyl sulfonate and 3g of polypropylene fiber with a length of 12mm to 30g of deionized water, stir evenly, keep warm at 90℃ for 3h, and dry to obtain pretreated polypropylene fiber. (2) Add 0.8g of silane coupling agent to 10g of deionized water, stir well, add sodium hydroxide, adjust the pH to 10, and obtain a mixed solution; (3) Add the pretreated polypropylene fiber obtained in step (1) to the mixture obtained in step (2), raise the temperature to 60°C, soak for 2 hours, cool, filter, wash, and dry at 60°C for 12 hours to obtain modified fiber.
[0033] Preparation Example 5 The difference from Preparation Example 1 is that no silane coupling agent was added. The specific preparation method is as follows: (1) Add 2g of carboxymethyl cellulose, 1g of sodium dodecyl sulfonate and 3g of polypropylene fiber with a length of 12mm to 20g of deionized water, stir evenly, keep warm at 90℃ for 3h, and dry to obtain pretreated polypropylene fiber. (2) Add 2.8g of polyvinyl alcohol to 10g of deionized water, stir well, add sodium hydroxide, adjust the pH to 10, and obtain a mixed solution; (3) Add the pretreated polypropylene fiber obtained in step (1) to the mixture obtained in step (2), raise the temperature to 60°C, soak for 2 hours, cool, filter, wash, and dry at 60°C for 12 hours to obtain modified fiber.
[0034] Preparation Example 6 The difference from Preparation Example 1 is that the 12 mm long polypropylene fibers are replaced by an equal amount of 3 mm long polypropylene fibers.
[0035] Preparation example of modified stone powder Sodium polyacrylate was purchased from Jiangsu Caiwei Biotechnology Co., Ltd., with a purity of 90% and product number 9003-04-7; fly ash was purchased from Wuhan Jiyesheng Chemical Co., Ltd., with product number A01085; granite powder was purchased from Baofeng Mineral Processing Plant, 325 mesh; acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer was purchased from Hubei Baidu Chemical Co., Ltd., with product number BD1432.
[0036] Preparation Example 1 (1) Add 3g of sodium polyacrylate to 20g of water and stir for 30min to obtain pretreated superabsorbent resin; (2) During the stirring process, 10g of granite powder was added to the pretreated superabsorbent resin and stirred for 40min. Then, 3g of fly ash was added and stirred for 30min. The mixture was dried at 60℃ for 24h, pulverized, and sieved through a 325-mesh sieve to obtain modified stone powder.
[0037] Preparation Example 2 (1) Add 2g of acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer to 20g of water and stir for 30min to obtain pretreated superabsorbent resin; (2) During the stirring process, 8g of granite powder was added to the pretreated superabsorbent resin and stirred for 40min. Then, 1g of fly ash was added and stirred for 30min. The mixture was dried at 60℃ for 24h, pulverized, and sieved through a 325-mesh sieve to obtain modified stone powder.
[0038] Preparation Example 3 The difference from Preparation Example 1 is that sodium polyacrylate was not added. The specific preparation method is as follows: during the stirring process, 10g of granite powder was added to 20g of water and stirred for 40min. Then, 3g of fly ash was added and stirred for 30min. The mixture was dried at 60℃ for 24h, pulverized, and sieved through a 325-mesh sieve to obtain modified stone powder.
[0039] Preparation Example 4 The difference from Preparation Example 1 is that no fly ash was added. Example
[0040] In the following examples, the crushed stone was purchased from Anhui Leitong New Building Materials Technology Co., Ltd.; the cement was purchased from Jiuqi Building Materials Co., Ltd., model PO42.5; the polycarboxylate superplasticizer was purchased from Jiangxi Anrui Building Materials Co., Ltd., model 101; the granite powder was purchased from Baofeng Mineral Processing Plant, 325 mesh; the polypropylene fiber was purchased from Hubei Kewode Chemical Co., Ltd., length 12mm; and the manufactured granite sand was purchased from Hebei Jiubao Building Materials Co., Ltd., particle size 2-4mm.
[0041] Example 1: A concrete containing granite manufactured sand, the raw material amounts are shown in Table 1. The modified stone powder is prepared by the method in Example 1 of modified stone powder preparation; the modified fiber is prepared by the method in Example 1 of modified fiber preparation; the modified fine aggregate is prepared by the method in Example 1 of modified fine aggregate preparation; the coarse aggregate is basalt 5-20mm continuously graded crushed stone; the cement is ordinary Portland cement; the water-reducing agent is polycarboxylate water-reducing agent.
[0042] The above-mentioned method for preparing concrete containing granite manufactured sand includes the following steps: adding modified fiber and water-reducing agent to water and mixing them evenly to obtain a mixed solution; adding cement, modified stone powder, modified fine aggregate and coarse aggregate to a concrete mixer and mixing them evenly to obtain a mixed powder; slowly pouring the mixed solution into the mixed powder being mixed and mixing it evenly to obtain concrete.
[0043] Table 1. Raw material consumption of concrete containing granite manufactured sand in Examples 1-4. Raw materials / kg Example 1 Example 2 Example 3 Example 4 cement 22 20 19 18 Modified stone powder 9 8 7 6 Modified fibers 10 9 8 8 Modified fine aggregate 32 31 30 30 coarse aggregate 45 43 42 40 Water reducing agent 0.7 0.6 0.5 0.5 water 20 19 17 15 Example 2: A concrete containing granite manufactured sand, differing from Example 1 in that the raw material quantities are as shown in Table 1; the modified stone powder is prepared using the method in Example 1 of modified stone powder preparation; the modified fiber is prepared using the method in Example 2 of modified fiber preparation; the modified fine aggregate is prepared using the method in Example 1 of modified fine aggregate preparation; the coarse aggregate is basalt 5-20mm continuously graded crushed stone; the cement is ordinary Portland cement; and the water-reducing agent is polycarboxylate water-reducing agent.
[0044] Example 3: A concrete containing granite manufactured sand, which differs from Example 1 in that the raw material quantities are as shown in Table 1; the modified stone powder is prepared using the method in Example 2 of modified stone powder preparation; the modified fiber is prepared using the method in Example 1 of modified fiber preparation; the modified fine aggregate is prepared using the method in Example 2 of modified fine aggregate preparation; the coarse aggregate is basalt 5-20mm continuously graded crushed stone; the cement is ordinary Portland cement; and the water-reducing agent is polycarboxylate water-reducing agent.
[0045] Example 4: A concrete containing granite manufactured sand, differing from Example 1 in that the raw material quantities are as shown in Table 1; the modified stone powder is prepared using the method in Example 2 of modified stone powder preparation; the modified fiber is prepared using the method in Example 2 of modified fiber preparation; the modified fine aggregate is prepared using the method in Example 2 of modified fine aggregate preparation; the coarse aggregate is basalt 5-20mm continuously graded crushed stone; the cement is ordinary Portland cement; and the water-reducing agent is polycarboxylate water-reducing agent.
[0046] Example 5: A concrete containing granite manufactured sand, which differs from Example 1 in that the modified stone powder is prepared using the method in Example 3 of modified stone powder preparation.
[0047] Example 6: A concrete containing granite manufactured sand, which differs from Example 1 in that the modified stone powder is prepared using the method in Example 4 of modified stone powder preparation.
[0048] Example 7: A concrete containing granite manufactured sand, which differs from Example 1 in that the modified fiber is prepared using the method in Modified Fiber Preparation Example 3.
[0049] Example 8: A concrete containing granite manufactured sand, which differs from Example 1 in that the modified fiber is prepared using the method in Modified Fiber Preparation Example 4.
[0050] Example 9: A concrete containing granite manufactured sand, which differs from Example 7 in that the modified fiber is prepared using the method in Modified Fiber Preparation Example 5.
[0051] Example 10: A concrete containing granite manufactured sand, which differs from Example 7 in that the modified fiber is prepared using the method in Modified Fiber Preparation Example 6.
[0052] Comparative Example Comparative Example 1: A concrete containing granite manufactured sand, which differs from Example 1 in that the modified fine aggregate is prepared using the method in Modified Fine Aggregate Preparation Example 3.
[0053] Comparative Example 2: A concrete containing granite manufactured sand, which differs from Example 1 in that the modified fine aggregate is prepared using the method in Modified Fine Aggregate Preparation Example 4.
[0054] Comparative Example 3: A concrete containing granite manufactured sand, which differs from Example 1 in that the modified fine aggregate is replaced by an equal amount of granite manufactured sand.
[0055] Comparative Example 4: A concrete containing granite manufactured sand, which differs from Example 1 in that the modified fiber is replaced with an equal amount of polypropylene fiber.
[0056] Comparative Example 5: A concrete containing granite manufactured sand, which differs from Example 1 in that the modified stone powder is replaced with an equal amount of granite stone powder.
[0057] Comparative Example 6: A concrete containing granite manufactured sand, which differs from Example 1 in that no modified fibers were added.
[0058] Performance testing Concrete containing granite manufactured sand was prepared according to the methods in the examples and comparative examples, and its performance was tested according to the following methods. The test results are recorded in Table 2.
[0059] 1. Workability: Workability is evaluated by the slump and spread of concrete. Both slump and spread are tested in accordance with GB / T 50080-2016 "Standard for Test Methods of Performance of Ordinary Concrete Mixtures".
[0060] 2. Compressive strength: The compressive strength is tested in accordance with GB / T 50081-2016 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete".
[0061] Table 2 shows the performance test results of concrete containing granite manufactured sand prepared in the examples and comparative examples. As shown in Table 2, the concrete containing granite manufactured sand prepared in Examples 1-4 of this application has good compressive strength and workability. The concrete prepared in Examples 5-6 and Comparative Example 5 differs from Example 1 in that one or both of sodium polyacrylate and fly ash were not added, and the agglomeration of granite powder led to a decrease in concrete workability. The concrete prepared in Examples 7-9 and Comparative Example 4 differs from Example 1 in that two or three of carboxymethyl cellulose, polyvinyl alcohol, and silane coupling agent were not added, respectively. The wettability of the modified fiber decreased, leading to a decrease in concrete workability; and the bonding strength between the modified fiber and the cement matrix and the tensile properties of the fiber decreased, resulting in a decrease in compressive strength. The following differences were observed in concrete preparations: In Example 10, the fiber length was reduced to 3 mm, which, while effectively filling the concrete gaps, caused the short fibers to agglomerate, leading to decreased workability and compressive strength. In Comparative Examples 1-3, the concrete was not added to either epoxy resin or silane coupling agent, thus the morphology and surface polarity of the granite manufactured sand were not improved, resulting in decreased compressive strength and workability. In Comparative Example 6, the concrete was not modified, leading to internal water loss and reduced workability, ultimately resulting in a decrease in both compressive strength and workability.
[0062] 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 containing manufactured granite sand, characterized in that, The raw materials include the following parts by weight: 18-22 parts cement, 6-9 parts modified stone powder, 8-10 parts modified fiber, 30-32 parts modified fine aggregate, 40-45 parts coarse aggregate, 0.5-0.7 parts water-reducing agent, and 15-20 parts water; the modified fine aggregate comprises granite manufactured sand, epoxy resin, and silane coupling agent in a mass ratio of 100:5-8:0.8-1; the preparation method of the modified fine aggregate includes the following steps: (1) Add the silane coupling agent to an ethanol-water solution, add acetic acid dropwise to adjust the pH to 4-5, stir for 30-40 min to obtain the activated silane coupling agent; (2) At 60-80℃, granite manufactured sand and epoxy resin are mixed evenly to obtain composite manufactured sand; (3) Add the composite manufactured sand to the activated silane coupling agent, stir evenly, dry, and obtain modified fine aggregate.
2. The concrete containing manufactured granite sand according to claim 1, characterized in that, The raw materials for the modified fiber include polypropylene fiber, carboxymethyl cellulose, polyvinyl alcohol, and silane coupling agent in a mass ratio of 1-3:1-2:1-2:0.5-0.
8.
3. The concrete containing manufactured granite sand according to claim 2, characterized in that, The method for preparing the modified fiber includes the following steps: (1) Add carboxymethyl cellulose, sodium dodecyl sulfonate and polypropylene fiber to deionized water, stir evenly, keep warm at 80-90℃ for 2-3 hours, and dry to obtain pretreated polypropylene fiber. (2) Add polyvinyl alcohol and silane coupling agent to deionized water, stir evenly, add sodium hydroxide, adjust pH to 9-10, and obtain a mixed solution; (3) Add the pretreated polypropylene fiber to the mixture, raise the temperature to 50-60℃, soak for 1-2 hours, cool, filter, wash and dry to obtain the modified fiber.
4. The concrete containing manufactured granite sand according to claim 3, characterized in that, The polypropylene fiber has a length of 6-12 mm.
5. The concrete containing manufactured granite sand according to claim 1, characterized in that, The method for preparing the modified stone powder includes the following steps: (1) Add superabsorbent resin to water and stir for 30-40 minutes to obtain pretreated superabsorbent resin; (2) During the stirring process, granite powder is added to the pretreated superabsorbent resin, stirred evenly, fly ash is added, stirred evenly, dried, crushed, and sieved to obtain modified stone powder. The mass ratio of the granite powder, fly ash, and superabsorbent resin is 8-10:1-3:2-3.
6. The concrete containing manufactured granite sand according to claim 5, characterized in that, The superabsorbent resin is selected from at least one of sodium polyacrylate and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer.
7. The concrete containing manufactured granite sand according to claim 1, characterized in that, The coarse aggregate is crushed stone.
8. The concrete containing manufactured granite sand according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate high-performance water-reducing agent.
9. A method for preparing concrete containing granite manufactured sand according to any one of claims 1-8, characterized in that, Includes the following steps: Modified fibers and water-reducing agents are added to water and mixed evenly to obtain a mixed solution; cement, modified stone powder, modified fine aggregate and coarse aggregate are mixed evenly to obtain a mixed powder; the mixed solution is slowly poured into the mixed powder being stirred and mixed evenly to obtain concrete.