Ultra-high performance concrete with low shrinkage and high elastic modulus and preparation method thereof

Abstract

The invention provides ultra-high performance concrete with low shrinkage and high elastic modulus and a preparation method thereof, and belongs to the technical field of concrete preparation. Comprising cement, aggregate, water, chemical additives, mineral admixtures, plant fibers and camphor. The plant fibers are added into the concrete, so that the tensile strength and the crack resistance of the concrete are improved, the overall density of the concrete can be reduced, the self weight of the concrete is reduced, the environmental protection property and the sustainable development property of the concrete are improved, and meanwhile, the camphor is added into the concrete, so that damage caused by freezing and melting of water in the concrete can be reduced; the anti-freezing performance of the concrete is improved, and the flowability and operability of the concrete can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete preparation, and in particular to an ultra-high performance concrete with low shrinkage and high elastic modulus and a preparation method thereof. Background Art

[0002] Ultra-high performance concrete is widely welcomed in the market because of its high strength, high toughness, high durability and high impact resistance. However, excessive use of cementitious materials not only causes large shrinkage and is prone to cracking, but also consumes a lot of energy, which is not in line with the concept of green development. In addition, in the design of component size, deformation is often the dominant factor in the design, and the elastic modulus of concrete is positively correlated with the component's ability to resist deformation. Therefore, increasing the elastic modulus is of great significance to reducing the size of the component.

[0003] For example, the application number is: CN202110919435.6, a kind of ultra-high performance concrete with low shrinkage and high elastic modulus and its preparation method. This invention is to solve the technical problems of large shrinkage and high cost of existing ultra-high performance concrete, and to improve the elastic modulus and enhance the level of resistance to deformation. The ultra-high performance concrete with low shrinkage and high elastic modulus of the present invention is prepared by mass fractions of cementitious material, sand, coarse aggregate, water reducer, arched copper-plated steel fiber and water. The method of the present invention: first pour the cementitious material and sand into a mixer for mixing and stirring, then add the pre-mixed water reducer and water and continue to stir, then slowly add the arched copper-plated steel fiber, and then stir to obtain mortar; pour an appropriate amount of mortar into the mold, then add an appropriate amount of coarse aggregate, and use a spatula to press the coarse aggregate into the mortar, repeat the process until the entire mold is filled; then steam cure to obtain concrete. The present invention has good economy, small shrinkage, and high level of resistance to deformation;

[0004] Although the above application can solve the technical problems of large shrinkage and high cost of existing ultra-high performance concrete, the produced concrete has poor performance, lacks sustainability and environmental protection, and the concrete has poor frost resistance. Therefore, this application provides an ultra-high performance concrete with low shrinkage and high elastic modulus and a preparation method thereof to meet the needs. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an ultra-high performance concrete with low shrinkage and high elastic modulus and a preparation method thereof to solve the existing problems.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] An ultra-high performance concrete with low shrinkage and high elastic modulus comprises, in terms of mass percentage, 15%-20% cement, 30%-40% aggregate, 5%-10% water, 1%-5% chemical additives, 20%-30% mineral admixtures, 0.5%-2% plant fiber, and 0.5%-3% camphor.

[0008] In some examples, the aggregate is divided into coarse aggregate and fine aggregate, and the ratio of coarse aggregate to fine aggregate is 2-3:7-8.

[0009] In some examples, the cement is silicate cement or special cement, the mineral admixtures include silica fume, fly ash, and limestone powder, the coarse aggregate is gravel, and the chemical additives include water reducing agent and air entraining agent.

[0010] In some examples, the plant fibers include bamboo fibers, jute fibers, hemp fibers, and straw fibers.

[0011] A method for preparing ultra-high performance concrete with low shrinkage and high elastic modulus comprises the following steps:

[0012] S1. In a dry mixing state, cement, aggregate, mineral admixture, plant fiber and camphor are fully mixed;

[0013] S2. Gradually add water, water reducing agent and air entraining agent, and stir until uniform. Ensure sufficient hydration and mixing during stirring;

[0014] S3, pour the mixture into the mold, remove bubbles by vibration or compaction, and after molding, perform preliminary curing, usually in a high humidity environment for 48 hours to 60 hours, and then demold;

[0015] S4. Carry out long-term water curing, usually not less than 14 days, to ensure that the concrete is fully hydrated;

[0016] S5. Conduct performance tests on concrete.

[0017] In some examples, the processing steps of the plant fiber in S1 are:

[0018] S111, washing the plant fibers to remove impurities on the surfaces of the plant fibers;

[0019] S112, drying the cleaned plant fibers to remove moisture from the surface and inside of the plant fibers;

[0020] S113. Cut the dried plant fibers to improve their dispersibility and bonding properties in concrete.

[0021] In some examples, the camphor in S1 is selected from high-quality camphor, which is usually in the form of granules or powder to ensure high purity and no impurities.

[0022] In some examples, the performance test in S6 includes:

[0023] Mechanical properties test: including compressive strength, tensile strength and elastic modulus, etc.;

[0024] Shrinkage performance test: Shrinkage performance is evaluated by measuring the dimensional changes of standard specimens under different curing conditions;

[0025] Durability testing: Evaluates concrete's resistance to penetration and chemical corrosion under different environmental conditions.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects:

[0027] 1. By adding plant fibers to concrete, plant fibers can improve the tensile strength and crack resistance of concrete, reduce the generation of microcracks, and increase the toughness of concrete through fiber distribution and cross-linking, making it more impact-resistant. The use of plant fibers can reduce the overall density of concrete and reduce its own weight. At the same time, plant fibers can improve the impermeability of concrete and enhance its durability. Furthermore, plant fibers are renewable and have good biodegradability, which is in line with the concept of sustainable development. Compared with traditional synthetic fibers, plant fibers are usually lower in cost. Plant fibers can improve the operability of concrete and reduce the difficulty of construction. Plant fibers have good thermal insulation and can improve the thermal performance of concrete.

[0028] Second, by adding camphor to concrete, camphor has good anti-permeability, can reduce the damage caused by freezing and melting of water inside the concrete, improve the frost resistance of concrete, and camphor can improve the fluidity and operability of concrete, especially in the case of low water-cement ratio, which is particularly important for the production of ultra-high performance concrete (UHPC). At the same time, camphor has certain antibacterial properties, which can help prevent the growth of microorganisms inside the concrete, thereby improving the durability of the concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable those skilled in the relevant art to make and use the present disclosure.

[0030] Figure 1 The present invention is a flow chart of the preparation method of ultra-high performance concrete with low shrinkage and high elastic modulus. DETAILED DESCRIPTION

[0031] The following is a detailed description of a low shrinkage and high elastic modulus ultra-high performance concrete and a preparation method thereof provided by the present invention in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are listed as the best and preferred embodiments, and other alternatives can also be used by technicians in some known technical fields; and the drawings are only for more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0032] It should be noted that the references to "one embodiment", "embodiment", "exemplary embodiment", "some embodiments" and the like in the specification indicate that the embodiments described may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, when a specific feature, structure or characteristic is described in conjunction with an embodiment, it should be within the knowledge of a person skilled in the art to implement such feature, structure or characteristic in conjunction with other embodiments (whether or not explicitly described).

[0033] In general, a term can be understood, at least in part, from its use in context. For example, depending, at least in part, on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but can instead, depending, at least in part, on the context, allow for the presence of other factors that are not necessarily explicitly described.

[0034] It will be understood that the meaning of “on,” “over,” and “above” in this disclosure should be interpreted in the broadest manner, so that “on” not only means “directly on” something, but also includes the meaning of being “on” something with intervening features or layers therebetween, and “on” or “over” not only means “on” or “above” something, but also includes the meaning of being “on” or “above” something with no intervening features or layers therebetween.

[0035] Additionally, spatially relative terms such as "under," "beneath," "lower," "above," "upper," and the like may be used herein for descriptive convenience to describe the relationship of one element or feature to another element or features, as shown in the accompanying drawings. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. The device may be oriented in other ways, and the spatially relative descriptors used herein may be similarly interpreted accordingly.

[0036] Example 1

[0037] An ultra-high performance concrete with low shrinkage and high elastic modulus and a preparation method thereof comprises, in terms of mass percentage, 20% cement, 35% aggregate, 10% water, 2% chemical additives, 30% mineral admixtures, 2% bamboo fiber, and 1% camphor.

[0038] This embodiment needs further explanation, the aggregate is divided into coarse aggregate and fine aggregate, and the ratio of coarse aggregate to fine aggregate is 2:8.

[0039] This embodiment needs further explanation: the cement is silicate cement or special cement, the mineral admixture includes a mixture of one or more of silica fume, fly ash, and limestone powder, the coarse aggregate is gravel, and the chemical additives include a water reducer and an air entraining agent.

[0040] By adding plant fibers to concrete, plant fibers can improve the tensile strength and crack resistance of concrete, reduce the generation of microcracks, and increase the toughness of concrete through fiber distribution and cross-linking, making it more impact-resistant. The use of plant fibers can reduce the overall density of concrete and reduce its own weight. At the same time, plant fibers can improve the impermeability of concrete and enhance its durability. Furthermore, plant fibers are renewable and have good biodegradability, which is in line with the concept of sustainable development. Compared with traditional synthetic fibers, plant fibers are usually lower in cost. Plant fibers can improve the operability of concrete and reduce the difficulty of construction. Plant fibers have good thermal insulation and can improve the thermal performance of concrete.

[0041] By adding camphor to concrete, camphor has good anti-permeability, can reduce the damage caused by freezing and melting of water inside the concrete, improve the frost resistance of concrete, and camphor can improve the fluidity and workability of concrete, especially in the case of low water-cement ratio, which is particularly important for the production of ultra-high performance concrete (UHPC). At the same time, camphor has certain antibacterial properties, which can help prevent the growth of microorganisms inside the concrete, thereby improving the durability of the concrete.

[0042] like Figure 1 As shown, a method for preparing ultra-high performance concrete with low shrinkage and high elastic modulus comprises the following steps:

[0043] S1. In a dry mixing state, cement, aggregate, mineral admixture, bamboo fiber and camphor are fully mixed;

[0044] S111, cleaning the bamboo fiber to remove impurities on the surface of the bamboo fiber;

[0045] S112, drying the cleaned bamboo fiber to remove moisture from the surface and inside of the bamboo fiber;

[0046] S113, cutting the dried bamboo fiber to improve its dispersibility and bonding in concrete;

[0047] S2. Gradually add water, water reducing agent and air entraining agent, and stir until uniform. Ensure sufficient hydration and mixing during stirring;

[0048] S3, pour the mixture into the mold, remove bubbles by vibration or compaction, and after molding, perform preliminary curing, usually in a high humidity environment for 48 hours to 60 hours, and then demold;

[0049] S4. Carry out long-term water curing, usually not less than 14 days, to ensure that the concrete is fully hydrated;

[0050] S5. Conduct performance tests on concrete.

[0051] It should be further explained in this example that the camphor in S1 is selected from high-quality camphor, which is usually in the form of granules or powder to ensure high purity and no impurities.

[0052] It should be further explained in this example that the performance test in S6 includes:

[0053] Mechanical properties test: including compressive strength, tensile strength and elastic modulus, etc.;

[0054] Shrinkage performance test: Shrinkage performance is evaluated by measuring the dimensional changes of standard specimens under different curing conditions;

[0055] Durability testing: Evaluates concrete's resistance to penetration and chemical corrosion under different environmental conditions.

[0056] Example 2

[0057] An ultra-high performance concrete with low shrinkage and high elastic modulus and a preparation method thereof, comprising, by weight percentage, 15% cement, 40% aggregate, 10% water, 3% chemical additives, 27% mineral admixtures, 3% jute fiber and hemp fiber, and 2% camphor.

[0058] This embodiment needs further explanation, the aggregate is divided into coarse aggregate and fine aggregate, and the ratio of coarse aggregate to fine aggregate is 3:7.

[0059] This embodiment needs further explanation: the cement is silicate cement or special cement, the mineral admixture includes a mixture of one or more of silica fume, fly ash, and limestone powder, the coarse aggregate is gravel, and the chemical additives include a water reducer and an air entraining agent.

[0060] By adding plant fibers to concrete, plant fibers can improve the tensile strength and crack resistance of concrete, reduce the generation of microcracks, and increase the toughness of concrete through fiber distribution and cross-linking, making it more impact-resistant. The use of plant fibers can reduce the overall density of concrete and reduce its own weight. At the same time, plant fibers can improve the impermeability of concrete and enhance its durability. Furthermore, plant fibers are renewable and have good biodegradability, which is in line with the concept of sustainable development. Compared with traditional synthetic fibers, plant fibers are usually lower in cost. Plant fibers can improve the operability of concrete and reduce the difficulty of construction. Plant fibers have good thermal insulation and can improve the thermal performance of concrete.

[0061] By adding camphor to concrete, camphor has good anti-permeability, can reduce the damage caused by freezing and melting of water inside the concrete, improve the frost resistance of concrete, and camphor can improve the fluidity and workability of concrete, especially in the case of low water-cement ratio, which is particularly important for the production of ultra-high performance concrete (UHPC). At the same time, camphor has certain antibacterial properties, which can help prevent the growth of microorganisms inside the concrete, thereby improving the durability of the concrete.

[0062] like Figure 1 As shown, a method for preparing ultra-high performance concrete with low shrinkage and high elastic modulus comprises the following steps:

[0063] S1. In a dry mixing state, cement, aggregate, mineral admixture, jute fiber, hemp fiber and camphor are fully mixed;

[0064] S111, cleaning the jute fiber and the hemp fiber to remove impurities on the surface of the jute fiber and the hemp fiber;

[0065] S112, drying the cleaned jute fibers and hemp fibers to remove moisture from the surfaces of the jute fibers and hemp fibers and from inside the jute fibers and hemp fibers;

[0066] S113, cutting the dried jute fiber and hemp fiber to improve their dispersibility and bonding properties in concrete;

[0067] S2. Gradually add water, water reducing agent and air entraining agent, and stir until uniform. Ensure sufficient hydration and mixing during stirring;

[0068] S3, pour the mixture into the mold, remove bubbles by vibration or compaction, and after molding, perform preliminary curing, usually in a high humidity environment for 48 hours to 60 hours, and then demold;

[0069] S4. Carry out long-term water curing, usually not less than 14 days, to ensure that the concrete is fully hydrated;

[0070] S5. Conduct performance tests on concrete.

[0071] It should be further explained in this example that the camphor in S1 is selected from high-quality camphor, which is usually in the form of granules or powder to ensure high purity and no impurities.

[0072] It should be further explained in this example that the performance test in S6 includes:

[0073] Mechanical properties test: including compressive strength, tensile strength and elastic modulus, etc.;

[0074] Shrinkage performance test: Shrinkage performance is evaluated by measuring the dimensional changes of standard specimens under different curing conditions;

[0075] Durability testing: Evaluates concrete's resistance to penetration and chemical corrosion under different environmental conditions.

[0076] Example 3

[0077] An ultra-high performance concrete with low shrinkage and high elastic modulus and a preparation method thereof comprises, in terms of mass percentage, 15% cement, 40% aggregate, 10% water, 5% chemical additives, 25% mineral admixtures, 2% straw fiber, and 3% camphor.

[0078] This embodiment needs further explanation. The aggregate is divided into coarse aggregate and fine aggregate, and the ratio of coarse aggregate to fine aggregate is 2.5:7.5.

[0079] This embodiment needs further explanation: the cement is silicate cement or special cement, the mineral admixture includes a mixture of one or more of silica fume, fly ash, and limestone powder, the coarse aggregate is gravel, and the chemical additives include a water reducer and an air entraining agent.

[0080] By adding plant fibers to concrete, plant fibers can improve the tensile strength and crack resistance of concrete, reduce the generation of microcracks, and increase the toughness of concrete through fiber distribution and cross-linking, making it more impact-resistant. The use of plant fibers can reduce the overall density of concrete and reduce its own weight. At the same time, plant fibers can improve the impermeability of concrete and enhance its durability. Furthermore, plant fibers are renewable and have good biodegradability, which is in line with the concept of sustainable development. Compared with traditional synthetic fibers, plant fibers are usually lower in cost. Plant fibers can improve the operability of concrete and reduce the difficulty of construction. Plant fibers have good thermal insulation and can improve the thermal performance of concrete.

[0081] By adding camphor to concrete, camphor has good anti-permeability, can reduce the damage caused by freezing and melting of water inside the concrete, improve the frost resistance of concrete, and camphor can improve the fluidity and workability of concrete, especially in the case of low water-cement ratio, which is particularly important for the production of ultra-high performance concrete (UHPC). At the same time, camphor has certain antibacterial properties, which can help prevent the growth of microorganisms inside the concrete, thereby improving the durability of the concrete.

[0082] like Figure 1 As shown, a method for preparing ultra-high performance concrete with low shrinkage and high elastic modulus comprises the following steps:

[0083] S1. In a dry mixing state, cement, aggregate, mineral admixture, straw fiber and camphor are fully mixed;

[0084] S111, washing the rice straw fibers to remove impurities on the surfaces of the rice straw fibers;

[0085] S112, drying the washed rice straw fibers to remove moisture from the surface and inside of the rice straw fibers;

[0086] S113, cutting the dried rice straw fibers to improve their dispersibility and bonding properties in concrete;

[0087] S2. Gradually add water, water reducing agent and air entraining agent, and stir until uniform. Ensure sufficient hydration and mixing during stirring;

[0088] S3, pour the mixture into the mold, remove bubbles by vibration or compaction, and after molding, perform preliminary curing, usually in a high humidity environment for 48 hours to 60 hours, and then demold;

[0089] S4. Carry out long-term water curing, usually not less than 14 days, to ensure that the concrete is fully hydrated;

[0090] S5. Conduct performance tests on concrete.

[0091] It should be further explained in this example that the camphor in S1 is selected from high-quality camphor, which is usually in the form of granules or powder to ensure high purity and no impurities.

[0092] It should be further explained in this example that the performance test in S6 includes:

[0093] Mechanical properties test: including compressive strength, tensile strength and elastic modulus, etc.;

[0094] Shrinkage performance test: Shrinkage performance is evaluated by measuring the dimensional changes of standard specimens under different curing conditions;

[0095] Durability testing: Evaluates concrete's resistance to penetration and chemical corrosion under different environmental conditions.

[0096] The technical solution provided by the present invention improves the tensile strength and crack resistance of concrete by adding plant fibers to concrete, and can reduce the overall density of concrete, reduce the dead weight, and improve the environmental protection and sustainable development of concrete. At the same time, adding camphor to concrete can reduce the damage caused by freezing and melting of water inside the concrete, improve the antifreeze performance of concrete, and can improve the fluidity and operability of concrete.

[0097] The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details. In addition, in order to avoid unnecessary confusion about the essence of the present invention, well-known methods, processes, procedures, components and circuits are not described in detail.

[0098] A person skilled in the art will appreciate that all or part of the steps in the above-mentioned embodiment method can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc.

[0099] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An ultra-high performance concrete with low shrinkage and high elastic modulus, characterized in that: In terms of mass percentage, it includes: cement 15% - 20%, aggregate 30% - 40%, water 5% - 10%, chemical additives 1% - 5%, mineral admixtures 20% - 30%, plant fiber 0.5% - 2%, and camphor 0.5% - 3%.

2. The ultra-high performance concrete with low shrinkage and high elastic modulus according to claim 1, characterized in that: The aggregate is divided into coarse aggregate and fine aggregate, and the ratio of coarse aggregate to fine aggregate is 2-3:7-8.

3. The ultra-high performance concrete with low shrinkage and high elastic modulus according to claim 1, characterized in that: The cement is silicate cement or special cement, the mineral admixtures include silica fume, fly ash, limestone powder, the coarse aggregate is gravel, and the chemical additives include water reducing agent and air entraining agent.

4. The ultra-high performance concrete with low shrinkage and high elastic modulus according to claim 1, characterized in that: The plant fibers include bamboo fibers, jute fibers, hemp fibers, and straw fibers.

5. A method for preparing ultra-high performance concrete with low shrinkage and high elastic modulus, applied to the ultra-high performance concrete with low shrinkage and high elastic modulus as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: S1. In a dry mixing state, cement, aggregate, mineral admixture, plant fiber and camphor are fully mixed; S2. Gradually add water, water reducing agent and air entraining agent, and stir until uniform. Ensure sufficient hydration and mixing during stirring; S3, pour the mixture into the mold, remove bubbles by vibration or compaction, and after molding, perform preliminary curing, usually in a high humidity environment for 48 hours to 60 hours, and then demold; S4. Carry out long-term water curing, usually not less than 14 days, to ensure that the concrete is fully hydrated; S5. Conduct performance tests on concrete.

6. The method for preparing ultra-high performance concrete with low shrinkage and high elastic modulus according to claim 5, characterized in that: The processing steps of the plant fiber in S1 are: S111, washing the plant fibers to remove impurities on the surfaces of the plant fibers; S112, drying the cleaned plant fibers to remove moisture from the surface and inside of the plant fibers; S113. Cut the dried plant fibers to improve their dispersibility and bonding properties in concrete.

7. The method for preparing ultra-high performance concrete with low shrinkage and high elastic modulus according to claim 5, characterized in that: The camphor in S1 is selected from high-quality camphor, which is usually in the form of granules or powder, ensuring high purity and no impurities.

8. The method for preparing ultra-high performance concrete with low shrinkage and high elastic modulus according to claim 5, characterized in that: The performance tests of S6 include: Mechanical properties test: including compressive strength, tensile strength and elastic modulus, etc.; Shrinkage performance test: Shrinkage performance is evaluated by measuring the dimensional changes of standard specimens under different curing conditions; Durability testing: Evaluates concrete's resistance to penetration and chemical corrosion under different environmental conditions.

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