Improved concrete with high crack resistance and preparation method thereof

Abstract

The invention relates to the field of concrete, in particular to improved concrete with high crack resistance and a preparation method thereof. The improved concrete with high crack resistance is prepared from the following raw materials in parts by mass: 160 to 180 parts of Portland cement, 60 to 100 parts of inorganic admixture, 1 to 5 parts of additive, 180 to 200 parts of water, 1000 to 1200 parts of coarse aggregate, 500 to 600 parts of fine aggregate, 15 to 25 parts of polyvinylidene chloride emulsion, 5 to 10 parts of bamboo fiber and 5 to 10 parts of basalt fiber. The crack resistance and durability of the concrete can be effectively improved.

Description

Technical Field

[0001] This application relates to the field of concrete, and more specifically, to an improved concrete with high crack resistance and its preparation method. Background Art

[0002] Concrete, as an essential basic material in construction engineering, occupies a crucial position in various building structures due to its high strength, excellent durability, and construction convenience. It can not only support huge buildings but also effectively resist the erosion of the external environment, ensuring the long-term stability and safety of buildings.

[0003] In the actual application of concrete, the crack resistance performance has become one of the key indicators to measure its quality. This is because once cracks appear in the concrete, it will not only damage the overall aesthetics of the building, but more importantly, it may also weaken the bearing capacity of the structure, reduce the durability, and even threaten the safety of the building. Especially under extreme climate conditions and complex geological environments, the crack resistance performance of concrete is even more important. Therefore, improving the crack resistance performance of concrete is not only to meet the high requirements of modern buildings for material performance, but also a necessary means to ensure building safety and extend the service life.

[0004] Traditional concrete materials often have deficiencies in crack resistance. On the one hand, due to the instability of raw material quality, unreasonable mix ratio, and defects in construction technology, problems such as shrinkage and deformation are likely to occur during the hardening process of concrete, thus leading to the generation of cracks. On the other hand, with the continuous improvement of the requirements for material performance in modern buildings, traditional concrete materials are already difficult to meet the growing crack resistance requirements. Therefore, improvement is still needed. Summary of the Invention

[0005] In order to improve the crack resistance of concrete, this application provides an improved concrete with high crack resistance and its preparation method.

[0006] In the first aspect, this application provides an improved concrete with high crack resistance, adopting the following technical solution: An improved concrete with high crack resistance, by mass, includes the following raw materials: 160 - 180 parts of portland cement, 60 - 100 parts of inorganic admixture, 1 - 5 parts of admixture, 180 - 200 parts of water, 1000 - 1200 parts of coarse aggregate, 500 - 600 parts fine aggregate, 15 - 25 parts of polyvinylidene chloride emulsion, 5 - 10 parts of bamboo fiber, 5 - 10 parts of basalt fiber.

[0007] By adopting the above technical solution, with the combined cooperation of polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber, the crack resistance and durability of concrete can be effectively improved.

[0008] Specifically, bamboo fiber and basalt fiber, as natural and inorganic fibers with excellent properties in nature, each have unique physical characteristics. Bamboo fiber is known for its high strength, high modulus, and good biodegradability, while basalt fiber is famous for its high temperature resistance, corrosion resistance, and excellent mechanical properties. When these two fibers are dispersed in concrete as the framework of polyvinylidene chloride emulsion, they form an intricate three-dimensional network structure. This structure can not only effectively disperse the stress inside the concrete and avoid cracking caused by local stress concentration, but also significantly improve the overall toughness and impact resistance of the concrete.

[0009] Moreover, the porous structure of bamboo fiber provides a penetration channel for polyvinylidene chloride emulsion. The emulsion can penetrate into the micropores of bamboo fiber, forming strong physical adsorption and chemical bonding, thus greatly enhancing the interfacial bonding force between the fiber and the emulsion. Further consolidating the connection among the three. This in-depth penetration and strengthening mechanism enables the entire composite system to work synergistically as a whole when subjected to external forces, improving the overall stability and durability.

[0010] The combination of polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber can not only play a role inside the concrete, but also form a dense protective film on the surface of the concrete. This film can effectively block the intrusion of moisture, oxygen, and harmful chemical substances, slow down the carbonation rate of the concrete and the corrosion process of steel bars, thus significantly extending the service life of the concrete structure. In addition, the film also has a certain self-healing ability, which can partially repair small cracks, further enhancing the durability of the concrete.

[0011] Preferably, by mass parts, the polyvinylidene chloride emulsion is 20 - 25 parts, the bamboo fiber is 8 - 10 parts, and the basalt fiber is 5 - 7 parts.

[0012] By adopting the above technical solution, further defining the dosage cooperation relationship of polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber in the system, enabling the bamboo fiber and basalt fiber to be more fully mixed with the polyvinylidene chloride emulsion, enhancing the role of the "framework", and making the mixed system of polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber play a more effective role in the concrete.

[0013] Preferably, the bamboo fiber and basalt fiber are 100 - 200 mesh.

[0014] By adopting the above technical solution, the bamboo fiber and basalt fiber are further crushed to 100 - 200 mesh, which can be used as fine particles to fill in the concrete and also play a good "framework" role.

[0015] Preferably, the inorganic admixture includes one or more mixtures of mineral powder, fly ash, bentonite, kaolin, expanded perlite.

[0016] Preferably, the inorganic admixture is mineral powder, fly ash, and expanded perlite, and the mass ratio of mineral powder, fly ash, and expanded perlite is 1:(0.8 - 1.2):(0.1 - 0.3).

[0017] By adopting the above technical solution, the types and dosage coordination relationships of the inorganic admixture are further defined. Expanded perlite is a lightweight material and has a phenomenon of floating in the slurry. When the mixed system of polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber penetrates into the internal structure of the concrete, it plays a certain role in fixing the expanded perlite, alleviates its floating phenomenon, enables the filling effect of the expanded perlite to be more fully exerted, and improves the crack resistance and durability of the concrete.

[0018] Preferably, the fine aggregate includes one or more of stone powder, river sand, and manufactured sand.

[0019] Second, the present application provides a preparation method of an improved concrete with high crack resistance, adopting the following technical solution: A preparation method of an improved concrete with high crack resistance includes the following steps: Step 1: Mix polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber evenly to obtain a premix; Step 2: Mix portland cement, fine aggregate, and inorganic admixture evenly to obtain a first mixture; Step 3: Mix the first mixture with water evenly to obtain a second mixture; Step 4: Mix the second mixture with the premix evenly to obtain a third mixture; Step 5: Mix the remaining raw materials with the third mixture evenly to obtain an improved concrete with high crack resistance.

[0020] By adopting the above technical solution, the polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber are premixed in advance, enabling the bamboo fiber and basalt fiber to be well distributed in the polyvinylidene chloride emulsion, which helps to exert the cooperative effect of the special system subsequently.

[0021] Then various raw materials are added and mixed in a specific order, combined more fully, so as to obtain concrete with high crack resistance and high durability.

[0022] Preferably, the polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber are mixed to obtain a premix under the condition of 1500 - 2000 r / min.

[0023] By adopting the above technical solution, mixing the polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber at a specific rotational speed helps to ensure uniform dispersion and coordination.

[0024] In summary, the present application has the following beneficial effects: 1. The synergistic effect of polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber can effectively enhance the crack resistance of concrete. The three-dimensional network structure formed by bamboo fiber and basalt fiber effectively disperses the internal stress of concrete, avoiding the cracking phenomenon caused by local stress concentration. At the same time, the penetration and strengthening mechanism of polyvinylidene chloride emulsion further enhances the adhesion between fiber and concrete, enabling the entire composite system to work together under external forces, improving the toughness and impact resistance of concrete. When concrete is faced with various external forces, it can maintain the integrity and stability of its structure and effectively resist the generation of cracks.

[0025] 2. Polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber form a dense protective film on the surface of concrete, effectively blocking the intrusion of moisture, oxygen, and harmful chemical substances. This protective film not only slows down the carbonation rate of concrete and the process of steel bar corrosion but also has a certain self-healing ability, capable of partially repairing tiny cracks. This self-healing mechanism enables concrete to maintain its good performance and stability during long-term use, significantly extending the service life of concrete structures. Specific Embodiments

[0026] The following further elaborates on the present application with reference to embodiments.

[0027] The raw materials used in the following embodiments and comparative examples are all commercially available products. Embodiments

[0028] Example 1 An improved concrete with high crack resistance includes the following raw materials: Portland cement, inorganic admixture, admixture, water, coarse aggregate, fine aggregate, polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber.

[0029] The Portland cement is commercially available P0 42.5 grade Portland cement.

[0030] The inorganic admixture is mineral powder, fly ash, and expanded perlite, and the mass ratio of mineral powder, fly ash, and expanded perlite is 1:1:0.2.

[0031] The admixture is a commercially available polycarboxylate superplasticizer.

[0032] The coarse aggregate is 5-25 mm gravel.

[0033] The fine aggregate is stone powder and river sand.

[0034] The polyvinylidene chloride emulsion is purchased from Dongguan Suda Plastic Raw Material Co., Ltd., A 736.

[0035] The bamboo fiber is commercially available and was purchased from Shandong Xuzheng Textile Co., Ltd. in this example.

[0036] For the specific dosages of each raw material, please refer to Table 1.

[0037] This example also provides a preparation method for an improved concrete with high crack resistance, which includes the following steps: Step 1: Put the bamboo fiber and basalt fiber into a crusher and crush them to 150 mesh.

[0038] Then mix the polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber at 1800 r / min for 15 min to obtain a premix.

[0039] Step 2: Mix the portland cement, fine aggregate, and inorganic admixture evenly to obtain a first mixture.

[0040] Step 3: Mix the first mixture with water evenly to obtain a second mixture.

[0041] Step 4: Mix the second mixture with the premix evenly to obtain a third mixture.

[0042] Step 5: Mix the remaining raw materials with the third mixture evenly to obtain the improved concrete with high crack resistance.

[0043] Example 2 An improved concrete with high crack resistance, which is different from that in Example 1 in that the mass ratio of mineral powder, fly ash, and expanded perlite is 1:0.8:0.3.

[0044] The fine aggregate is river sand.

[0045] The specific dosages of each raw material are different. Please refer to Table 1 for details.

[0046] A preparation method for an improved concrete with high crack resistance, which is different from that in Example 1 in that some parameters are different. Specifically, it includes the following steps: Step 1: Put the bamboo fiber and basalt fiber into a crusher and crush them to 100 mesh.

[0047] Then mix the polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber at 1500 r / min for 15 min to obtain a premix.

[0048] Step 2: Mix the portland cement, fine aggregate, and inorganic admixture evenly to obtain a first mixture.

[0049] Step 3: Mix the first mixture with water evenly to obtain a second mixture.

[0050] Step 4: Mix the second mixture with the premix evenly to obtain a third mixture.

[0051] Step 5: Mix the remaining raw materials with the third mixture until uniform to obtain an improved concrete with high crack resistance.

[0052] Example 3 An improved concrete with high crack resistance, which is different from that of Example 1 in that the mass ratio of mineral powder, fly ash, and expanded perlite is 1:1.2:0.1.

[0053] The fine aggregate is manufactured sand.

[0054] The specific dosages of each raw material are different, as shown in Table 1 for details.

[0055] A preparation method of an improved concrete with high crack resistance, which is different from that of Example 1 in that some parameters are different. It specifically includes the following steps: Step 1: Put bamboo fiber and basalt fiber into a pulverizer and pulverize them to 200 meshes.

[0056] Then mix polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber under the condition of 2000 r / min for 15 min to obtain a premix.

[0057] Step 2: Mix portland cement, fine aggregate, and inorganic admixture until uniform to obtain a first mixture.

[0058] Step 3: Mix the first mixture with water until uniform to obtain a second mixture.

[0059] Step 4: Mix the second mixture with the premix until uniform to obtain a third mixture.

[0060] Step 5: Mix the remaining raw materials with the third mixture until uniform to obtain an improved concrete with high crack resistance.

[0061] Table 1 Example 4 A preparation method of an improved concrete with high crack resistance, which is different from that of Example 1 in that polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber are mixed under the condition of 180 r / min for 15 min to obtain a premix.

[0062] Comparative Example Comparative Example 1 An improved concrete with high crack resistance, which is different from that of Example 1 in that polyvinylidene chloride emulsion is replaced by polyvinyl acetate emulsion.

[0063] The polyvinyl acetate emulsion is purchased from Jinan Mingxin Chemical Co., Ltd.

[0064] Comparative Example 2 An improved concrete with high crack resistance, which is different from Example 1 in that bamboo fibers are replaced by hydroxyethyl cellulose.

[0065] Comparative Example 3 An improved concrete with high crack resistance, which is different from Example 1 in that basalt fibers are replaced by glass cellulose.

[0066] Comparative Example 4 An improved concrete with high crack resistance, which is different from Example 1 in that polyvinylidene chloride emulsion, bamboo fibers, and basalt fibers are omitted.

[0067] Performance detection test 1. Compressive strength: The compressive properties of the improved concrete with high crack resistance in Examples 1-4 and Comparative Examples 1-4 were detected in accordance with GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", and the compressive strength was recorded in Table 2.

[0068] 2. Splitting tensile strength: The splitting tensile properties of the improved concrete with high crack resistance in Examples 1-4 and Comparative Examples 1-4 were detected in accordance with GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", and the splitting tensile strength was recorded in Table 2.

[0069] 3. Durability: The chloride ion penetration resistance of the improved concrete with high crack resistance in Examples 1-4 and Comparative Examples 1-4 was detected by the RCM method in accordance with GB / T 50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete", and the chloride ion diffusion coefficient results were recorded in Table 2. Table 2 Group Compressive strength (MPa) Splitting tensile strength (MPa) <![CDATA[Durability (×10 -12 m 2 / s)]]> Example 1 42.5 3.95 1.0 Example 2 41.6 3.82 1.2 Example 3 42.2 3.93 1.1 Example 4 41.8 3.76 1.1 Comparative Example 1 39.2 2.95 2.3 Comparative Example 2 40.1 3.02 2.1 Comparative Example 3 38.6 2.83 2.5 Comparative Example 4 36.5 2.34 2.9 Comparative Example 4 is based on Example 1, with polyvinylidene chloride emulsion, bamboo fibers, and basalt fibers omitted, which is equivalent to simulating common concrete on the market. According to the test data in Table 2, the compressive strength and splitting tensile strength of the concrete in Comparative Example 4 are significantly lower than those in Examples 1-4, and the chloride ion penetration resistance of Comparative Example 4 is significantly greater than that in Examples 1-4. It shows that the performance of the concrete in Comparative Example 4 in terms of compression and crack resistance is significantly inferior to that in Examples 1-4, and its durability is also poor.

[0070] On the basis of Example 1, in Comparative Examples 1-3, any one of the polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber was replaced with other raw materials. According to the test data in Table 2, the splitting tensile strength of Comparative Examples 1-3 was significantly lower than that of Example 1, and the chloride ion permeability was also much greater than that of Example 1. In terms of compressive strength, Comparative Examples 1-3 also decreased compared with Example 1. This shows that arbitrarily destroying the special combination of polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber cannot form a special system, thus unable to effectively improve the crack resistance and durability of concrete.

[0071] Example 4 was based on Example 1, but changed the premixing conditions of the polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber. According to the test data in Table 2, the performance of the concrete in Example 1 with better premixing conditions was slightly better than that of Example 4 in terms of compressive strength, crack resistance, and durability. This shows that if the mixing conditions of the polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber can be further defined, the cooperation effect of the three can be more fully utilized, thereby improving the performance of the concrete.

[0072] This specific embodiment is only an interpretation of the present application, and it is not a limitation of the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An improved concrete with high crack resistance, characterized in that, By mass parts, it includes the following raw materials: 160 - 180 parts of portland cement, 60 - 100 parts of inorganic admixture, 1 - 5 parts of admixture, 180 - 200 parts of water, 1000 - 1200 parts of coarse aggregate, 500 - 600 parts of fine aggregate, 15 - 25 parts of polyvinylidene chloride emulsion, 5 - 10 parts of bamboo fiber, and 5 - 10 parts of basalt fiber.

2. The improved concrete with high crack resistance according to claim 1, characterized in that: By mass parts, the polyvinylidene chloride emulsion is 20 - 25 parts, the bamboo fiber is 8 - 10 parts, and the basalt fiber is 5 - 7 parts.

3. The improved concrete with high crack resistance according to claim 1, characterized in that: The bamboo fiber and basalt fiber are 100 - 200 mesh.

4. The improved concrete with high crack resistance according to claim 1, characterized in that: The inorganic admixture includes one or more mixtures of slag powder, fly ash, bentonite, kaolin, expanded perlite.

5. The improved concrete with high crack resistance according to claim 4, characterized in that: The inorganic admixture is slag powder, fly ash, expanded perlite, and the mass ratio of slag powder, fly ash, expanded perlite is 1:(0.8 - 1.2):(0.1 - 0.3).

6. The improved concrete with high crack resistance according to claim 1, characterized in that: The fine aggregate includes one or more mixtures of stone powder, river sand, and manufactured sand.

7. A method for preparing an improved concrete with high crack resistance according to any one of claims 1-6, characterized in that, It includes the following steps: Step 1: Mix the polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber evenly to obtain a premix. Step 2: Mix the portland cement, fine aggregate, and inorganic admixture evenly to obtain a first mixture. Step 3: Mix the first mixture with water evenly to obtain a second mixture. Step 4: Mix the second mixture with the premix evenly to obtain a third mixture. Step 5: Mix the remaining raw materials with the third mixture evenly to obtain an improved concrete with high crack resistance.

8. The preparation method of the improved concrete with high crack resistance according to claim 7, characterized in that: The polyvinylidene chloride emulsion, bamboo fiber, and basalt fiber are mixed under the condition of 1500 - 2000 r / min to obtain a premix.

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