Ultrahigh-strength prefabricated part concrete and preparation method thereof

Abstract

The invention relates to the technical field of building materials, and discloses ultrahigh-strength prefabricated part concrete and a preparation method thereof, and the concrete comprises the following raw materials by weight: 10-12% of Portland cement; 6%-10% of rice hull ash; 6%-9% of silica fume; 5%-9% of fly ash; 4%-6% of slag powder; 21%-23% of quartz sand; 20%-25% of granite; 18%-21% of basalt; 1%-3% of steel fiber; 1%-3% of carbon fiber; 1%-2% of a defoaming agent; 1%-3% of a water reducing agent; 0.01%-0.1% of a retarder; the preparation method comprises the following steps: mixing and stirring the quartz sand, the slag powder, the Portland cement, the rice hull ash, the silica fume and the fly ash into dry powder, equally dividing the water A, the water B and the water C into three parts, mixing the water A with the water reducing agent, mixing the water B with the defoaming agent, and adding the dry powder into the water C to obtain the mortar. And sequentially adding granite, basalt, steel fiber, carbon fiber, the expanding agent, the water mixed solution A, the water mixed solution B and the retarder into mortar, stirring, discharging, forming and curing to obtain the concrete.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and specifically to a super-high-strength precast concrete member and a preparation method thereof. Background Art

[0002] In the current construction industry, problems such as low structural bearing capacity, poor durability, and inability to meet complex engineering requirements are becoming increasingly prominent. These problems seriously restrict the development process of building industrialization. Traditional building materials and construction methods often struggle to meet the requirements of modern building designs for high strength, high stability, and long lifespan, especially in the face of extreme weather conditions or special geological environments. In addition, with the acceleration of urbanization, the comprehensive consideration of the functionality and aesthetics of buildings is also getting higher and higher, and traditional technical means have obvious limitations in this regard. Therefore, the development of new high-performance materials and advanced construction technologies has become the key to promoting the transformation and upgrading of the construction industry. This can not only effectively improve the safety and service life of buildings, but also promote the construction of a resource-saving society and lay a solid foundation for achieving sustainable development goals. Summary of the Invention

[0003] (1) Technical Problems to be Solved

[0004] Aiming at the deficiencies of the prior art, the present invention provides a super-high-strength precast concrete member and a preparation method thereof, which have the advantages of high structural bearing capacity, durability, and the ability to meet complex engineering requirements, and solve the problems of low structural bearing capacity, poor durability, and inability to meet complex engineering requirements in the current construction industry.

[0005] (2) Technical Solutions

[0006] To achieve the above object, the present invention provides the following technical solution: A super-high-strength precast concrete member, the concrete is composed of cement, fine aggregate, coarse aggregate, mineral admixture, fiber material, and admixture. The raw materials and their weight ratio ranges are as follows: Portland cement 10% - 12%; rice husk ash 6% - 10%; silica fume 6% - 9%; fly ash 5% - 9%; slag powder 4% - 6%; quartz sand 21% - 23%; granite 20% - 25%; basalt 18% - 21%; steel fiber 1% - 3%; carbon fiber 1% - 3%; defoamer 1% - 2%; water reducer 1% - 3%; retarder 0.01% - 0.1%; expansive agent 4% - 12%, and the remaining raw material is water.

[0007] Preferably, the Portland cement constitutes the cement, and its cement dosage is between 600 - 1000 kg / m 3 The rice husk ash, silica fume, fly ash, and slag powder form the mineral admixture. The particle size of the rice husk ash is between 100 nanometers and 200 nanometers. The cement and the mineral admixture together form the gel material.

[0008] Preferably, the fineness modulus of the quartz sand ranges from 2.2 to 1.6, and the average particle size is 0.35 to 0.25 mm. The quartz sand constitutes fine aggregate, and the amount of fine aggregate used is between 690 and 710 kg / m 3 Between, the particle shapes of the granite and basalt should be close to spherical. The granite and basalt form coarse aggregate, and the amount of coarse aggregate used is between 950 and 1100 kg / m 3 Between, the steel fiber and carbon fiber form fiber material, and the defoaming agent, water reducing agent, setting retarder and expansive agent form admixture.

[0009] Preferably, the raw materials and their weight ratios are: Portland cement 10%; rice husk ash 6%; silica fume 6%; fly ash 5%; slag powder 4%; quartz sand 21%; granite 29%; basalt 19%; steel fiber 2.5%; carbon fiber 1.5%; defoaming agent 1%; water reducing agent 1.3%; setting retarder 0.09%; expansive agent 8%, and the remaining raw material is water.

[0010] Preferably, the raw materials and their weight ratios are: Portland cement 12%; rice husk ash 8%; silica fume 9%; fly ash 8%; slag powder 5%; quartz sand 23%; granite 21%; basalt 18%; steel fiber 1%; carbon fiber 3%; defoaming agent 1.6%; water reducing agent 1.53%; setting retarder 0.03%; expansive agent 9%, and the remaining raw material is water.

[0011] Preferably, a preparation method of ultra-high strength precast concrete component is prepared according to the raw materials and their weight ratios of the above-mentioned ultra-high strength precast concrete component, and includes the following preparation steps:

[0012] Step 1: Prepare Portland cement, rice husk ash, silica fume, fly ash, slag powder, quartz sand, granite, basalt, steel fiber, carbon fiber, defoaming agent, water reducing agent, setting retarder, expansive agent and water according to the formula weight parts;

[0013] Step 2: After adding the quartz sand and slag powder to the mixer for preliminary mixing, add Portland cement, rice husk ash, silica fume and fly ash and mix and stir at low speed to form dry powder;

[0014] Step 3: Divide the water into three equal parts A, B and C. Part A of water is mixed with the water reducing agent, part B of water is mixed with the defoaming agent, and part C of water is reserved;

[0015] Step 4: Mix the dry powder mixture prepared in Step 2 with part C of water, stir until it becomes sticky, and then stir quickly until it becomes fluid to obtain mortar;

[0016] Step 5: Add granite, basalt, steel fibers and carbon fibers into the mortar and stir until the granite, basalt, steel fibers and carbon fibers are evenly dispersed;

[0017] Step 6: Add an expansion agent into the mortar;

[0018] Step 7: Add the A and B portion water mixture into the mortar containing the expansion agent, add a retarder and continue to stir until uniform;

[0019] Step 8: Discharge the material, form and cure the concrete mixture to obtain concrete.

[0020] Preferably, the dry powder mixing conditions in Step 2 are: set the mixer temperature to 25 - 40 °C, the stirring speed to 50 - 100 r / min, and the stirring duration to 3 - 5 min.

[0021] Preferably, the slump of the sticky state in Step 4 is maintained between 30 mm and 50 mm, and the slump of the flowing state is maintained between 180 mm and 200 mm.

[0022] Preferably, the mixing conditions of granite, basalt, steel fibers and carbon fibers in Step 5 are: set the mixer temperature to 20 - 30 °C, the stirring speed to 100 - 200 r / min, and the stirring duration to 4 - 6 min.

[0023] Preferably, the curing process of the concrete mixture in Step 8 is as follows:

[0024] S8.1, Initial curing: Carry out initial curing within 4 - 12 hours after the concrete is poured;

[0025] Temperature control during the initial curing process: Cover with wet cloth and wet gunny bags to control the ambient temperature between 30 - 40 °C, and water once every 1 - 1.2 h;

[0026] S8.2, Steam curing: Steam curing is divided into four stages: static stop, temperature rise, constant temperature, and temperature drop;

[0027] Temperature control during the steam curing process: Keep the ambient temperature at 5 - 20 °C during the static stop period, the temperature rise rate < 10 °C / h, the internal temperature of the concrete is 60 °C - 65 °C during the constant temperature period, the temperature drop rate < 10 °C / h, and the final temperature of the temperature drop is 5 °C - 10 °C;

[0028] S8.3, Post - curing: Carry out post - curing more than 7 days after the concrete is poured.

[0029] Compared with the prior art, the present invention provides a super - high - strength precast concrete member and its preparation method, having the following beneficial effects:

[0030] 1. The present invention improves the strength foundation of concrete by adding high-quality cement, namely Portland cement, to the raw materials. This significantly enhances the compressive strength of the concrete, enabling it to withstand greater loads. By adding silica fume and fly ash, since silica fume can fill the tiny pores in the concrete, it helps to improve the compactness of the concrete. At the same time, fly ash can improve the workability and durability of the concrete. The combined use of the above admixtures can enhance the strength, durability, and anti-permeability performance of the concrete. Granite and basalt, as high-strength aggregates, can better withstand the internal stress of the concrete and improve the overall strength of the concrete. Under the condition of meeting the same structural load-bearing requirements, the amount of concrete used in construction can be reduced. Reducing the amount of concrete can lower the energy consumption and carbon dioxide emissions during cement production. Cement production is an industry with high energy consumption and high emissions. Reducing the amount of cement helps to protect the environment. Therefore, in construction projects, the procurement cost of raw materials can be reduced, not only reducing the raw material cost and transportation cost, but also achieving the goal of energy conservation and emission reduction.

[0031] 2. Through the high-efficiency mixing process, the ultra-high-strength concrete prepared by the present invention can withstand greater loads, enabling the structural design to be more compact, reducing the sizes of beams, columns, and slabs, thereby increasing the usable space of the building. Reducing the structural size can also reduce the self-weight of the building, reduce the size and cost of the foundation in foundation engineering. At the same time, it can also reduce the structural response under earthquake action and lower the cost of seismic reinforcement.

[0032] 3. By using high-performance water reducers, retarders, and expansive agents, the water reducer can improve the fluidity of the concrete without increasing the water consumption. The retarder can not only adjust the setting time of the concrete but also facilitate construction. The use of the expansive agent can compensate for the shrinkage of the concrete, thereby reducing the generation of cracks. The reasonable use of the above admixtures helps to improve the workability, strength, and durability of the concrete.

[0033] 4. The ultra-high-strength concrete of the present invention has good durability, which helps to reduce the frequency of structural maintenance and replacement, thereby reducing resource consumption and waste generation, meeting the requirements of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a flowchart for the preparation of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] Please refer to Figure 1 , a kind of ultra-high-strength precast concrete component. The concrete is composed of cement, fine aggregate, coarse aggregate, mineral admixture, fiber material and admixture. The raw materials and their weight ratio ranges are as follows: Portland cement 10% - 12%; rice husk ash 6% - 10%; silica fume 6% - 9%; fly ash 5% - 9%; slag powder 4% - 6%; quartz sand 21% - 23%; granite 20% - 25%; basalt 18% - 21%; steel fiber 1% - 3%; carbon fiber 1% - 3%; defoamer 1% - 2%; water reducing agent 1% - 3%; retarder 0.01% - 0.1%; expansive agent 4% - 12%, and the remaining raw material is water.

[0037] The advantages are as follows: By adding high-quality cement in the raw materials and using Portland cement, the strength foundation of the concrete is improved, which enables a significant increase in the compressive strength of the concrete and enables it to withstand greater loads. By adding silica fume and fly ash, since silica fume can fill the tiny pores in the concrete, it helps to improve the density of the concrete. At the same time, fly ash can improve the workability and durability of the concrete. The combined use of the above admixtures can enhance the strength, durability and impermeability of the concrete. And granite and basalt, as high-strength aggregates, can better withstand the internal stress of the concrete and improve the overall strength of the concrete.

[0038] Specifically, the Portland cement constitutes the cement, and its cement dosage is between 600 - 1000 kg / m 3 ³. Rice husk ash, silica fume, fly ash and slag powder form the mineral admixture (silica fume has extremely high activity and can improve the strength and density of the concrete, while fly ash and slag powder can reduce the heat of hydration of the concrete, improve the impermeability and chemical corrosion resistance). The admixture can improve the workability of the concrete, increase the strength and durability. The particle size of rice husk ash is between 100 nanometers and 200 nanometers. The cement and the mineral admixture together form the gel material.

[0039] Specifically, the fineness modulus range of the quartz sand is 2.2 - 1.6, and the average particle size is 0.35 - 0.25 mm. The fineness modulus is appropriate, the mud content is low, and the particle size distribution is good to ensure the workability and strength of the concrete. The quartz sand constitutes the fine aggregate, and its fine aggregate dosage is between 690 - 710 kg / m 3 ³. The particle shapes of granite and basalt should be close to spherical to reduce the void ratio and improve the density of the concrete. Granite and basalt form the coarse aggregate, and its coarse aggregate dosage is between 950 - 1100 kg / m 3Between them, steel fibers and carbon fibers form a fiber material. By adding steel fibers and carbon fibers, the tensile strength, crack resistance, and toughness of concrete can be improved. The fibers play a role in strengthening and crack resistance in the concrete, making the concrete more durable. The defoamer, water reducer, retarder, and expansive agent form admixtures (the water reducer can ensure the fluidity of concrete under a low water-binder ratio, reduce the water consumption, and improve the strength and durability of concrete, and the retarder can adjust the setting time and early strength development of concrete).

[0040] The advantages are as follows: By using high-performance water reducers, retarders, and expansive agents, the water reducer can improve the fluidity of concrete without increasing the water consumption. The retarder can not only adjust the setting time of concrete but also facilitate construction. The use of the expansive agent can compensate for the shrinkage of concrete, thus reducing the generation of cracks. The reasonable use of the above admixtures helps to improve the workability, strength, and durability of concrete.

[0041] Specifically, a preparation method of ultra-high-strength precast concrete components is prepared according to the raw materials and their weight ratios of the above-mentioned ultra-high-strength precast concrete components, including the following preparation steps:

[0042] Step 1: Prepare portland cement, rice husk ash, silica fume, fly ash, slag powder, quartz sand, granite, basalt, steel fibers, carbon fibers, defoamer, water reducer, retarder, expansive agent, and water according to the formula weight parts;

[0043] Step 2: Add quartz sand and slag powder to a mixer for preliminary mixing, and then add portland cement, rice husk ash, silica fume, and fly ash for mixing and stirring. Mix at low speed to prevent dry powder from splashing, forming a dry powder mixture;

[0044] Step 3: Divide the water into three equal parts, namely A, B, and C. Mix part A of the water with the water reducer, mix part B of the water with the defoamer, and reserve part C of the water;

[0045] Step 4: Mix the dry powder mixture prepared in Step 2 with part C of the water, stir until it reaches an adhesive state, and then quickly stir until it reaches a fluid state to obtain mortar;

[0046] Step 5: Add granite, basalt, steel fibers, and carbon fibers to the mortar and stir until the granite, basalt, steel fibers, and carbon fibers are evenly dispersed;

[0047] Step 6: Add the expansive agent to the mortar to improve the performance of the concrete;

[0048] Step 7: Add the mixture of part A and part B of the water to the mortar containing the expansive agent, and add the retarder and continue to stir until it is uniform;

[0049] Step 8: Discharge the material, form and cure the concrete mixture to obtain concrete.

[0050] The advantages are as follows: Through an efficient mixing process, advanced mixing equipment and techniques are adopted for step-by-step mixing, which can ensure that all components of the concrete are fully and evenly mixed, contributing to improving the strength uniformity and workability of the concrete, reducing internal defects. During the preparation process, precise control over the quality of raw materials, mix proportion, mixing time, and pouring temperature can guarantee the stable quality of the concrete. Finally, through high-temperature and high-pressure curing, the hydration reaction of the concrete can be accelerated, the early strength of the concrete can be increased, and at the same time, the microscopic structure of the concrete can be improved, enhancing its density and durability.

[0051] Specifically, the mixing conditions for the dry powder materials in step two are: set the mixer temperature at 25 - 40 °C, the mixing speed at 50 - 100 r / min, and the mixing duration at 3 - 5 min.

[0052] Specifically, in step four, the slump of the adhesive state is maintained between 30 mm and 50 mm, and the slump of the flowing state is maintained between 180 mm and 200 mm.

[0053] Specifically, the mixing conditions for granite, basalt, steel fibers, and carbon fibers in step five are: set the mixer temperature at 20 - 30 °C, the mixing speed at 100 - 200 r / min, and the mixing duration at 4 - 6 min.

[0054] The concrete mixture has good fluidity, cohesiveness, and water retention. The measured slump is above 200 mm, and the spread is above 500 mm.

[0055] Specifically, the curing process of the concrete mixture in step eight is as follows:

[0056] S8.1, Initial curing: Initial curing is carried out within 4 - 12 hours after the concrete is poured, aiming to avoid excessive internal temperature and humidity gradients and reduce crack generation;

[0057] Temperature control during the initial curing process: Cover with wet cloth and wet gunny bags to control the ambient temperature between 30 - 40 °C, water every 1 - 1.2 h to prevent premature evaporation of water, lay wet cloth to increase humidity, and spray a moisture retention agent to enhance density and water retention;

[0058] S8.2, Steam curing: Steam curing is divided into four stages: static stop, heating, constant temperature, and cooling;

[0059] Temperature control during the steam curing process: Keep the ambient temperature at 5 - 20 °C during the static stop period, the heating rate < 10 °C / h, the internal temperature of the concrete is 60 °C - 65 °C during the constant temperature period, the cooling rate < 10 °C / h, and the final cooling temperature is 5 °C - 10 °C;

[0060] S8.3, Post - curing: Post - curing is carried out more than 7 days after concrete pouring. The purpose is to make the temperature and humidity inside and outside the concrete uniform, promoting the improvement of strength and durability. The specific operations include spraying water to keep the surface moist, laying wet cloth to increase humidity, and covering with plastic film to prevent water evaporation.

[0061] Advantages: Through the improvement of the above - mentioned materials, processes and technologies, ultra - high - strength concrete has been improved in terms of strength, durability, impermeability, crack resistance and toughness, and can meet the requirements of modern engineering construction for high - performance concrete.

[0062] This Example 1

[0063] Specifically, the raw materials and their weight ratios are: Portland cement 10%; rice husk ash 6%; silica fume 6%; fly ash 5%; slag powder 4%; quartz sand 21%; granite 29%; basalt 19%; steel fiber 2.5%; carbon fiber 1.5%; defoamer 1%; water - reducing agent 1.3%; retarder 0.09%; expansive agent 8%, and the remaining raw material is water.

[0064] Example 2

[0065] Specifically, the raw materials and their weight ratios are: Portland cement 12%; rice husk ash 8%; silica fume 9%; fly ash 8%; slag powder 5%; quartz sand 23%; granite 21%; basalt 18%; steel fiber 1%; carbon fiber 3%; defoamer 1.6%; water - reducing agent 1.53%; retarder 0.03%; expansive agent 9%, and the remaining raw material is water.

[0066] Example 3

[0067] Specifically, the raw materials and their weight ratios are: Portland cement 11%; rice husk ash 7%; silica fume 8%; fly ash 5.5%; slag powder 4.3%; quartz sand 22%; granite 22.5%; basalt 19.3%; steel fiber 1.25%; carbon fiber 2.13%; defoamer 1.65%; water - reducing agent 2.25%; retarder 0.088%; expansive agent 7.7%, and the remaining raw material is water.

[0068] Example 4

[0069] According to the formula of the present invention, it is prepared according to the preparation steps of the present invention, and finally the curing step is carried out.

[0070] Comparative Example 1

[0071] Specifically, the raw materials and their weight ratios are as follows: Portland cement 10%; rice husk ash 6%; silica fume 6%; fly ash 5%; slag powder 4%; quartz sand 21%; granite 29%; basalt 19%; steel fiber 2.5%; carbon fiber 1.5%; defoamer 1%; water reducing agent 1.3%; retarder 0.09%; expansive agent 8%, and the remaining raw material is water (delete 6% of rice husk ash and 4% of slag powder in the example);

[0072] Rice husk ash and slag powder, as admixtures, can improve the pore structure of concrete, enhance the density and impermeability, thereby enhancing the durability. Removing these two materials will cause a decrease in the strength and durability of the concrete.

[0073] Comparative Example 2

[0074] Specifically, the raw materials and their weight ratios are as follows: Portland cement 12%; rice husk ash 8%; silica fume 9%; fly ash 8%; slag powder 5%; quartz sand 23%; granite 21%; basalt 18%; steel fiber 1%; carbon fiber 3%; defoamer 1.6%; water reducing agent 1.53%; retarder 0.03%; expansive agent 9%, and the remaining raw material is water (delete 23% of quartz sand in the example);

[0075] Quartz sand, as fine aggregate, helps to improve the compressive strength and tensile strength of concrete, enabling the prepared concrete to have appropriate fluidity while also having appropriate cohesiveness and stability. Therefore, deleting quartz sand will cause the mechanical properties, fluidity and cohesiveness of the concrete to deteriorate.

[0076] Comparative Example 3

[0077] Specifically, the raw materials and their weight ratios are as follows: cement 11%; rice husk ash 7%; silica fume 8%; fly ash 5.5%; slag powder 4.3%; quartz sand 22%; granite 22.5%; basalt 19.3%; steel fiber 1.25%; carbon fiber 2.13%; defoamer 1.65%; water reducing agent 2.25%; retarder 0.088%; expansive agent 7.7%, and the remaining raw material is water (replace Portland cement in Example 3 with ordinary cement).

[0078] High-quality cement: Using high-strength grade cement to improve the strength foundation of concrete. This results in a significant increase in the compressive strength of the concrete, enabling it to withstand greater loads.

[0079] Comparative Example 4

[0080] According to the formula of the present invention, curing is carried out according to the traditional method.

[0081] For the concrete prepared according to the above examples and comparative examples, performance tests were carried out, and the test data are as shown in the following table:

[0082] Performance Index Unit Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Compressive Strength MPa 180-200 185-195 192-212 45-55 40-50 48-58 48-58 Tensile Strength MPa 5-7 6-8 5.5-7.5 4-6 3-5 4.5-6.5 4.5-6.5 Durability - High High High Reduced Reduced Reduced Reduced Flowability - Excellent Excellent Excellent - Worsened Excellent Reduced Cohesion - Excellent Excellent Excellent - Worsened Excellent Reduced Compactness - High High High Reduced - High Reduced Impermeability - Excellent Excellent Excellent Reduced - Excellent Reduced Shrinkage Rate ％ 0.02-0.03 0.02-0.03 0.02-0.03 0.03-0.04 0.03-0.04 0.02-0.03 0.03-0.04 Creep ％ 1-2 1-2 1-2 2-3 2-3 1.5-2.5 2-3

[0083] Performance Summary of Examples and Comparative Examples

[0084] Compressive strength: The compressive strengths of Examples 1, 2, and 3 are relatively high, all in the range of 180 - 220 MPa, indicating that the formulations of the present invention can all provide relatively high strength; in Comparative Example 1, due to the removal of rice husk ash and slag powder, and in Comparative Example 2, due to the reduction of quartz sand, the compressive strengths of Comparative Example 1 and Comparative Example 2 decreased, being 45 - 55 MPa and 40 - 50 MPa respectively; in Comparative Example 3, the portland cement was replaced with ordinary cement, and in Comparative Example 4, the traditional curing method was replaced, resulting in the compressive strengths of Comparative Example 3 and 4 being between 48 - 58 MPa, respectively lower than those of Examples 3 and 4.

[0085] Tensile strength: The tensile strengths of the examples are all higher than those of the comparative examples, with a range of 5 - 8 MPa, showing good tensile properties of the examples; due to the removal of rice husk ash and slag powder and the reduction of quartz sand in Comparative Example 1 and Comparative Example 2, the tensile strengths of Comparative Example 1 and Comparative Example 2 decreased, being 4 - 6 MPa and 3 - 5 MPa respectively, while in Comparative Example 3, the portland cement was replaced with ordinary cement, and in Comparative Example 4, the traditional curing method was replaced, resulting in the tensile strengths of Comparative Example 3 and Comparative Example 4 being between 4.5 - 6.5 MPa, both lower than those of the examples.

[0086] Durability: The durability of the examples is relatively high, while in Comparative Example 1 and Comparative Example 2, due to the removal of rice husk ash, slag powder and the reduction of quartz sand, the durability decreased, and the durability of Comparative Example 4 also decreased because the traditional curing method is not as good as the curing steps of the present invention.

[0087] Flowability and cohesiveness: The flowability and cohesiveness of the examples are both excellent, while the flowability and cohesiveness of Comparative Example 2 became worse due to the reduction of quartz sand.

[0088] Density and impermeability: The density and impermeability of the examples are relatively high, while the density and impermeability of Comparative Example 1 and Comparative Example 4 decreased due to the removal of rice husk ash and slag powder.

[0089] Shrinkage rate: The shrinkage rates of the examples are relatively low, in the range of 0.02% - 0.03%, indicating relatively low shrinkage performance, which is beneficial to reducing cracks. The shrinkage rates of Comparative Example 1, 2, 3, and 4 increased, in the range of 0.03% - 0.04%, which will increase the risk of cracks.

[0090] Creep: The creep of the examples is relatively low, in the range of 1% - 2%, indicating good long-term stability, while the creep of Comparative Example 1, 2, and 4 is relatively high, in the range of 2% - 3%, which will affect the long-term performance of the concrete.

[0091] In summary, the concrete properties of the examples are superior to those of the comparative examples, indicating that the formulation and preparation steps of the present invention can provide higher strength, durability, density, and impermeability, while having a lower shrinkage rate and creep, thereby improving the overall performance of the concrete. In contrast, the performance of the comparative examples has decreased due to the reduction or replacement of raw materials and different curing methods.

[0092] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An ultra-high strength precast component concrete, characterized in that: The concrete is composed of cement, fine aggregate, coarse aggregate, mineral admixture, fiber material and admixture. The raw materials and their weight ratio range are: 10% to 12% of silicate cement; 6% to 10% of rice husk ash; 6% to 9% of silica ash; 5% to 9% of fly ash; 4% to 6% of slag powder; 21% to 23% of quartz sand; 20% to 25% of granite; 18% to 21% of basalt; 1% to 3% of steel fiber; 1% to 3% of carbon fiber; 1% to 2% of defoamer; 1% to 3% of water reducer; 0.01% to 0.1% of retarder; 4% to 12% of expansion agent, and the remaining raw materials are water.

2. The ultra-high strength precast component concrete according to claim 1, characterized in that: The silicate cement is used in an amount of 600-1000 kg / m 3 The rice husk ash, silica ash, fly ash and slag powder constitute mineral admixtures, the particle size of the rice husk ash is between 100 nanometers and 200 nanometers, and the cement and the mineral admixtures together constitute a gel material.

3. The method for preparing ultra-high strength prefabricated component concrete according to claim 1, characterized in that: The fineness modulus of the quartz sand is in the range of 2.2-1.6, and the average particle size is 0.35-0.25 mm. The quartz sand constitutes fine aggregate, and the amount of fine aggregate is 690-710 kg / m 3 The particle shape of the granite and basalt should be close to spherical. The granite and basalt constitute the coarse aggregate, and the amount of the coarse aggregate is 950-1100kg / m 3 The steel fiber and the carbon fiber constitute the fiber material, and the defoamer, the water reducing agent, the retarder and the expansion agent constitute the admixture.

4. The ultra-high strength precast component concrete according to claim 1, characterized in that: The raw materials and their weight ratios are: 10% silicate cement; 6% rice husk ash; 6% silica ash; 5% fly ash; 4% slag powder; 21% quartz sand; 29% granite; 19% basalt; 2.5% steel fiber; 1.5% carbon fiber; 1% defoamer; 1.3% water reducer; 0.09% retarder; 8% expansion agent, and the remaining raw material is water.

5. The ultra-high strength precast component concrete according to claim 1, characterized in that: The raw materials and their weight ratios are: 12% silicate cement; 8% rice husk ash; 9% silica ash; 8% fly ash; 5% slag powder; 23% quartz sand; 21% granite; 18% basalt; 1% steel fiber; 3% carbon fiber; 1.6% defoamer; 1.53% water reducer; 0.03% retarder; 9% expansion agent, and the remaining raw material is water.

6. A method for preparing ultra-high strength prefabricated component concrete, characterized in that: The raw materials and weight ratio of the ultra-high strength prefabricated component concrete according to claim 1 are prepared, comprising the following preparation steps: Step 1, prepare silicate cement, rice husk ash, silica ash, fly ash, slag powder, quartz sand, granite, basalt, steel fiber, carbon fiber, defoamer, water reducer, retarder, expansion agent and water according to the formula weight parts; Step 2: After adding quartz sand and slag powder into a mixer for preliminary mixing, add silicate cement, rice husk ash, silica ash and fly ash and mix them under low speed stirring to form a dry powder; Step 3: Divide the water into three equal parts: A, B, and C. Mix the A part of water with the water reducing agent, mix the B part of water with the defoaming agent, and keep the C part of water for later use. Step 4: Mix the dry powder prepared in step 2 with C parts of water, stir until it becomes sticky, and then stir quickly until it becomes fluid to obtain mortar; Step 5: Add granite, basalt, steel fiber and carbon fiber into the mortar and stir until the granite, basalt, steel fiber and carbon fiber are evenly dispersed; Step 6: Add expansion agent to the mortar; Step 7: Add the mixture of parts A and B of water into the mortar containing the expansion agent, add the retarder and continue stirring until it is uniform; Step 8: Discharging, molding and curing the concrete mixture to obtain concrete.

7. The method for preparing ultra-high strength precast component concrete according to claim 6, characterized in that: The mixing conditions of the dry powder in step 2 are: setting the mixer temperature to 25-40° C., the stirring speed to 50-100 r / min, and the stirring time to 3-5 min.

8. The method for preparing ultra-high strength precast component concrete according to claim 6, characterized in that: In the step 4, the slump in the adhesive state is maintained between 30 mm and 50 mm, and the slump in the flow state is maintained between 180 mm and 200 mm.

9. The method for preparing ultra-high strength prefabricated component concrete according to claim 6, characterized in that: The mixing conditions of the granite, basalt, steel fiber and carbon fiber in step 5 are as follows: the mixer temperature is set to 20-30° C., the stirring speed is set to 100-200 r / min, and the stirring time is set to 4-6 min.

10. The method for preparing ultra-high strength prefabricated component concrete according to claim 6, characterized in that: The curing process of the concrete mixture in step eight is as follows: S8.

1. Initial curing: Initial curing should be carried out within 4 to 12 hours after concrete pouring; Temperature control during the initial curing process: Cover with wet cloth and wet sacks to control the ambient temperature between 30-40℃, and water every 1-1.2 hours; S8.2, Steam curing: Steam curing is divided into four stages: static stop, heating, constant temperature and cooling; Temperature control during steam curing: During the static period, the ambient temperature is maintained at 5-20℃, the heating rate is <10℃ / h, during the constant temperature period, the internal temperature of the concrete is 60℃-65℃, the cooling rate is <10℃ / h, and the final temperature of the cooling is 5℃-10℃; S8.

3. Post-curing: Post-curing shall be carried out more than 7 days after concrete pouring.

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