Ultrahigh performance concrete in alpine regions and preparation method thereof
By combining aluminate cement, additives, and functional auxiliaries in specific proportions, high-density ultra-high-performance UHPC concrete for cold regions is prepared, solving the problem of insufficient compressive strength of concrete in cold regions and achieving excellent compressive, flexural, and frost resistance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LIAONING PENGSHUO TECH CO LTD
- Filing Date
- 2026-05-08
- Publication Date
- 2026-07-10
AI Technical Summary
Existing concrete in high-altitude and cold regions has limited compressive strength when subjected to extremely high loads, resulting in insufficient durability.
Using a specific ratio of aluminate cement, additives, and functional auxiliaries, additive powder and pretreated boron mud are prepared through microwave pyrolysis and ball milling. Combined with steel fibers, quartz sand, and polycarboxylate superplasticizer, a high-density concrete matrix is formed. High-temperature steam curing is then used to improve the hydration reaction rate and structural stability.
It significantly improves the compressive strength and freeze-thaw resistance of concrete, extends its service life, and is suitable for ultra-high performance UHPC concrete in cold regions.
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Figure CN122145122B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of concrete technology, specifically to an ultra-high performance UHPC concrete for high-altitude and cold regions and its preparation method. Background Technology
[0002] Ultra-high performance concrete is a new type of building material with a low water-cement ratio and no coarse aggregate, and it has excellent mechanical properties and durability.
[0003] In existing technologies, concrete used in high-altitude and cold regions often suffers from insufficient matrix density, resulting in limited compressive strength under extremely high loads and thus compromising its durability. Therefore, this invention provides an ultra-high performance UHPC concrete for high-altitude and cold regions and its preparation method. Summary of the Invention
[0004] The purpose of this invention is to provide an ultra-high performance UHPC concrete for high-altitude and cold regions and its preparation method. The concrete prepared by this invention not only has good frost resistance but also excellent compressive and flexural strength, effectively improving the performance of the concrete.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-performance UHPC concrete for cold regions, prepared from the following raw materials in parts by weight: 480-560 parts aluminate cement, 20-40 parts additives, 45-75 parts functional additives, 520-580 parts quartz sand, 70-80 parts steel fiber, 12-20 parts polycarboxylate superplasticizer, and 100-120 parts water;
[0006] The additive raw materials include additive powder and pretreated boron mud;
[0007] The functional additives include triethanolamine, cellulose alkyl ethers, anhydrous ethanol, silane coupling agent KH550, nano-silica, straw ash, and bamboo fiber.
[0008] Preferably, the additive preparation method includes the following steps: mixing the additive powder with pretreated boron mud at a mass ratio of 1:(0.6-1.2), placing it in a microwave pyrolysis furnace, heating it to 500-600°C at a heating rate of 10-15°C / min under a nitrogen atmosphere, holding it at that temperature for 40-60 min, cooling it to 20-25°C with the furnace, and pulverizing it through a 100-200 mesh sieve to obtain the additive.
[0009] Preferably, the preparation method of the additive powder includes the following steps: crushing and cleaning the cathode carbon block and passing it through a 100-mesh sieve, collecting the sieve material to obtain coarse powder, mixing the coarse powder with silica fume at a mass ratio of 1:(0.6-1.2) to obtain mixed powder, placing the mixed powder in a ball mill, adding 0.3-0.5% of the mass of the mixed powder in a first mixed liquid, grinding for 60-90 minutes, and passing it through a 100-200-mesh sieve to obtain the additive powder.
[0010] Preferably, the preparation method of the first mixture includes the following steps: heating water to 40-50°C, adding sodium dodecyl sulfate and polydimethylsiloxane, stirring at 300-500 r / min for 15-20 min, and cooling to 23-25°C to obtain the first mixture, wherein the mass ratio of water, sodium dodecyl sulfate and polydimethylsiloxane is 10:(0.5-2):(0.1-0.5).
[0011] Preferably, the preparation method of the pretreated boron mud is as follows: soapberry powder and water are mixed at a ratio of 1:(10-20), stirred at 70-90℃ and 50-80r / min for 10-20min, and then filtered to obtain the filtrate, which is used as a second mixture. The boron mud is dried, pulverized and passed through a 100-200 mesh sieve, and then added to the second mixture to obtain the pretreated boron mud. The mass ratio of boron mud to the second mixture is 1:(3-6).
[0012] Preferably, the preparation method of the functional additive includes the following steps:
[0013] Step A: Mix triethanolamine and water at a mass ratio of 1:(5-8) and stir for 5-10 minutes at 20-30℃ and 40-60r / min to obtain the first treatment agent;
[0014] Step B: Mix cellulose alkyl ether with water at a mass ratio of (0.1-0.5):(8-10) to obtain a first mixture for later use. Mix water, anhydrous ethanol, silane coupling agent KH550, and nano silica to obtain a second mixture. Mix the first mixture and the second mixture at a mass ratio of 1:(1-3) and stir at 20-40 r / min for 10-15 min to obtain the second treatment agent.
[0015] Step C: Mix straw ash with the first treatment agent at a mass ratio of 1:(2-4), stir for 30-60 min at 40-60℃ and 40-60 r / min, filter and dry to obtain the treated straw ash;
[0016] Step D: Mix bamboo fiber with the second treatment agent, soak at 40-50℃ for 2-4 hours, and dry to obtain treated bamboo fiber;
[0017] Step E: Mix the treated straw ash, treated bamboo fiber and water at a mass ratio of 1:(2-3):(8-10), stir at 30-50 r / min for 30-60 min at 50-70℃, filter and retain the filter residue, and then wash and dry to obtain the functional additive.
[0018] Preferably, the mass ratio of water, anhydrous ethanol, silane coupling agent KH550 and nano silica is 1:3:(0.25-0.5):(0.8-1.5).
[0019] Preferably, the method for preparing ultra-high performance UHPC concrete in high-altitude and cold regions is characterized by comprising the following steps:
[0020] Step 1: Add aluminate cement, additives, and quartz sand into a mixer and dry mix for 2-3 minutes at a speed of 30-40 r / min to obtain the first mixture;
[0021] Step 2: Add water and polycarboxylate superplasticizer to the first mixture, stir for 5-8 minutes at a speed of 40-50 r / min to obtain the second mixture;
[0022] Step 3: Add steel fibers and functional additives to the second mixture, stir for 10-15 minutes at a speed of 50-80 r / min to obtain concrete mixture;
[0023] Step 4: After pouring the concrete mixture into the mold, it is cured with high-temperature steam for 14 days to obtain ultra-high performance UHPC concrete for cold regions.
[0024] Compared with the prior art, the beneficial effects of the present invention are:
[0025] 1. In this invention, the additive consists of additive powder and pretreated boron mud. After being refined, the additive powder particles can effectively fill the cement paste, thereby improving the initial density of the matrix. The pretreated boron mud, after being activated by soapberry powder solution, provides active chemical components that can participate in the reaction during cement hydration to generate more stable hydrated calcium silicate gel products, thereby strengthening the paste structure. Under the dual action of additive powder and pretreated boron mud, the overall density of concrete is significantly improved, thus enabling the concrete to exhibit stronger compressive strength when subjected to extremely high loads and extending the service life of the concrete.
[0026] 2. In this invention, the functional additive is composed of treated straw ash, bamboo fiber, triethanolamine, and silane coupling agent KH550. Triethanolamine can effectively promote the hydration reaction of aluminate cement and improve the generation rate and stability of hydration products. Silane coupling agent KH550 can improve the interfacial compatibility between the inorganic and organic phases, allowing the treated straw ash and bamboo fiber to bond more tightly with the cement matrix. Cellulose alkyl ether and nano silica can further fill the matrix. The straw ash with enhanced activity after the first treatment agent can undergo a secondary reaction with the cement hydration products. The bamboo fiber soaked in the second treatment agent forms a fiber reinforcement network in the matrix, effectively improving the concrete's resistance to bending deformation and fracture.
[0027] 3. In this invention, the additives and functional aids work together. The additive powder, after being refined by ball milling, can be embedded in the voids of the cement paste, optimizing the particle size distribution of the entire material. This makes the concrete more compact in the early stages of molding, reducing the original internal pores. The activated boron mud provides active chemical components and reacts with hydration products to generate more gel. The synergistic effect of the additives and functional aids significantly enhances the ability to resist freeze-thaw damage, making it more suitable for use in cold regions. Attached Figure Description
[0028] Figure 1 The present invention provides a flowchart of an ultra-high performance UHPC concrete for high-altitude and cold regions and its preparation method. Detailed Implementation
[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0030] It should be noted that the raw materials used in the following embodiments are all commercially available.
[0031] Example 1
[0032] A high-performance UHPC concrete for cold regions is prepared from the following raw materials in parts by weight: 480 parts aluminate cement, 20 parts additives, 45 parts functional additives, 520 parts quartz sand, 70 parts steel fiber, 12 parts polycarboxylate superplasticizer, and 100 parts water.
[0033] The additive raw materials include additive powder and pretreated boron mud;
[0034] The functional additives include triethanolamine, cellulose alkyl ethers, anhydrous ethanol, silane coupling agent KH550, nano silica, straw ash, and bamboo fiber.
[0035] The additive preparation method includes the following steps: the additive powder and pretreated boron mud are mixed at a mass ratio of 1:0.6, placed in a microwave pyrolysis furnace, heated to 500°C at a heating rate of 10°C / min under a nitrogen atmosphere, held for 40 min, cooled to 20°C with the furnace, and pulverized through a 100-mesh sieve to obtain the additive.
[0036] The preparation method of the additive powder includes the following steps: after crushing and cleaning the cathode carbon block, it is passed through a 100-mesh sieve, and the sieve material is collected to obtain coarse powder. The coarse powder is mixed with silica fume at a mass ratio of 1:0.6 to obtain mixed powder. The mixed powder is placed in a ball mill, and 0.3% of the mass of the mixed powder is added to the first mixed liquid. The mixture is ground for 60 minutes and passed through a 100-mesh sieve to obtain the additive powder.
[0037] The preparation method of the first mixture includes the following steps: heating water to 40°C, adding sodium dodecyl sulfate and polydimethylsiloxane, stirring at 300 r / min for 15 min, and cooling to 23°C to obtain the first mixture, wherein the mass ratio of water, sodium dodecyl sulfate and polydimethylsiloxane is 10:0.5:0.1.
[0038] The preparation method of pretreated boron mud is as follows: soapberry powder and water are mixed at a ratio of 1:10, stirred at 70℃ and 50r / min for 10min, filtered and the filtrate is collected to obtain a second mixture for later use. The boron mud is dried, pulverized and passed through a 100-mesh sieve, and then added to the second mixture to obtain pretreated boron mud. The mass ratio of boron mud to the second mixture is 1:3.
[0039] The preparation method of functional additives includes the following steps:
[0040] Step A: Mix triethanolamine and water at a mass ratio of 1:5 and stir for 5 minutes at 20°C and 40 r / min to obtain the first treatment agent;
[0041] Step B: Mix cellulose alkyl ether with water at a mass ratio of 0.1:8 to obtain the first mixture for later use. Mix water, anhydrous ethanol, silane coupling agent KH550, and nano silica to obtain the second mixture. Mix the first mixture and the second mixture at a mass ratio of 1:1 and stir at 20 r / min for 10 min to obtain the second treatment agent.
[0042] Step C: Mix straw ash with the first treatment agent at a mass ratio of 1:2, stir for 30 minutes at 40℃ and 40r / min, filter and dry to obtain the treated straw ash;
[0043] Step D: Mix bamboo fiber with the second treatment agent, soak at 40°C for 2 hours, and dry to obtain treated bamboo fiber;
[0044] Step E: Mix the treated straw ash, treated bamboo fiber and water at a mass ratio of 1:2:8, stir at 50℃ and 30r / min for 30min, filter and retain the filter residue, and then wash and dry to obtain the functional additive.
[0045] The mass ratio of water, anhydrous ethanol, silane coupling agent KH550, and nano silica is 1:3:0.25:0.8.
[0046] A method for preparing ultra-high performance UHPC concrete in high-altitude and cold regions, characterized by comprising the following steps:
[0047] Step 1: Add aluminate cement, additives, and quartz sand into a mixer and dry mix for 2 minutes at a speed of 30 r / min to obtain the first mixture;
[0048] Step 2: Add water and polycarboxylate superplasticizer to the first mixture, stir for 5 minutes at a speed of 40 r / min to obtain the second mixture;
[0049] Step 3: Add steel fibers and functional additives to the second mixture, stir for 10 minutes at a speed of 50 r / min to obtain concrete mixture;
[0050] Step 4: After pouring the concrete mixture into the mold, it is cured with high-temperature steam for 14 days to obtain ultra-high performance UHPC concrete for cold regions.
[0051] Example 2
[0052] A high-performance UHPC concrete for high-altitude and cold regions is prepared from the following raw materials in parts by weight: 520 parts aluminate cement, 30 parts additives, 55 parts functional additives, 550 parts quartz sand, 75 parts steel fiber, 16 parts polycarboxylate superplasticizer, and 110 parts water.
[0053] The additive raw materials include additive powder and pretreated boron mud;
[0054] The functional additives include triethanolamine, cellulose alkyl ethers, anhydrous ethanol, silane coupling agent KH550, nano silica, straw ash, and bamboo fiber.
[0055] The additive preparation method includes the following steps: the additive powder and pretreated boron mud are mixed at a mass ratio of 1:0.9, placed in a microwave pyrolysis furnace, heated to 550°C at a heating rate of 12°C / min under a nitrogen atmosphere, held at that temperature for 50 min, cooled to 22°C with the furnace, and pulverized through a 150-mesh sieve to obtain the additive.
[0056] The preparation method of the additive powder includes the following steps: after crushing and cleaning the cathode carbon block, it is passed through a 100-mesh sieve, and the sieve material is collected to obtain coarse powder. The coarse powder is mixed with silica fume at a mass ratio of 1:0.9 to obtain mixed powder. The mixed powder is placed in a ball mill, and 0.4% of the mass of the mixed powder is added to the first mixed liquid. The mixture is ground for 75 minutes and passed through a 150-mesh sieve to obtain the additive powder.
[0057] The preparation method of the first mixture includes the following steps: heating water to 45°C, adding sodium dodecyl sulfate and polydimethylsiloxane, stirring at 400 r / min for 18 min, and cooling to 24°C to obtain the first mixture, wherein the mass ratio of water, sodium dodecyl sulfate and polydimethylsiloxane is 10:1:0.3.
[0058] The preparation method of pretreated boron mud is as follows: soapberry powder and water are mixed at a ratio of 1:15, stirred at 80℃ and 65r / min for 15min, filtered and the filtrate is collected to obtain a second mixture for later use. The boron mud is dried, pulverized and passed through a 150-mesh sieve, and then added to the second mixture to obtain pretreated boron mud. The mass ratio of boron mud to the second mixture is 1:4.
[0059] The preparation method of functional additives includes the following steps:
[0060] Step A: Mix triethanolamine and water at a mass ratio of 1:6 and stir for 8 minutes at 25°C and 50 r / min to obtain the first treatment agent;
[0061] Step B: Mix cellulose alkyl ether with water at a mass ratio of 0.3:9 to obtain the first mixture for later use. Mix water, anhydrous ethanol, silane coupling agent KH550, and nano silica to obtain the second mixture. Mix the first mixture and the second mixture at a mass ratio of 1:2 and stir at 30 r / min for 12 min to obtain the second treatment agent.
[0062] Step C: Mix straw ash with the first treatment agent at a mass ratio of 1:3, stir at 50℃ and 50r / min for 45min, filter and dry to obtain treated straw ash;
[0063] Step D: Mix bamboo fiber with the second treatment agent, soak at 45°C for 3 hours, and dry to obtain treated bamboo fiber;
[0064] Step E: Mix the treated straw ash, treated bamboo fiber and water at a mass ratio of 1:2.5:9, stir at 60℃ and 40r / min for 45min, filter and retain the filter residue, and then wash and dry to obtain the functional additive.
[0065] The mass ratio of water, anhydrous ethanol, silane coupling agent KH550, and nano silica is 1:3:0.35:1.1.
[0066] A method for preparing ultra-high performance UHPC concrete in high-altitude and cold regions, characterized by comprising the following steps:
[0067] Step 1: Add aluminate cement, additives, and quartz sand to the mixer and dry mix for 2.5 minutes at a speed of 35 r / min to obtain the first mixture;
[0068] Step 2: Add water and polycarboxylate superplasticizer to the first mixture, stir for 6 minutes at a speed of 45 r / min to obtain the second mixture;
[0069] Step 3: Add steel fibers and functional additives to the second mixture, stir for 12 minutes at a speed of 60 r / min to obtain concrete mixture;
[0070] Step 4: After pouring the concrete mixture into the mold, it is cured with high-temperature steam for 14 days to obtain ultra-high performance UHPC concrete for cold regions.
[0071] Example 3
[0072] A high-performance UHPC concrete for high-altitude and cold regions is prepared from the following raw materials in parts by weight: 560 parts aluminate cement, 40 parts additives, 75 parts functional additives, 580 parts quartz sand, 80 parts steel fibers, 20 parts polycarboxylate superplasticizer, and 120 parts water.
[0073] The additive raw materials include additive powder and pretreated boron mud;
[0074] The functional additives include triethanolamine, cellulose alkyl ethers, anhydrous ethanol, silane coupling agent KH550, nano silica, straw ash, and bamboo fiber.
[0075] The additive preparation method includes the following steps: the additive powder and pretreated boron mud are mixed at a mass ratio of 1:1.2, placed in a microwave pyrolysis furnace, heated to 600°C at a heating rate of 15°C / min under a nitrogen atmosphere, held at that temperature for 60 min, cooled to 25°C with the furnace, and pulverized through a 200-mesh sieve to obtain the additive.
[0076] The preparation method of the additive powder includes the following steps: after crushing and cleaning the cathode carbon block, it is passed through a 100-mesh sieve, and the sieve material is collected to obtain coarse powder. The coarse powder is mixed with silica fume at a mass ratio of 1:1.2 to obtain mixed powder. The mixed powder is placed in a ball mill, and 0.5% of the mass of the mixed powder is added to the first mixed liquid. The mixture is ground for 90 minutes and passed through a 200-mesh sieve to obtain the additive powder.
[0077] The preparation method of the first mixture includes the following steps: heating water to 50°C, adding sodium dodecyl sulfate and polydimethylsiloxane, stirring at 500 r / min for 20 min, and cooling to 25°C to obtain the first mixture, wherein the mass ratio of water, sodium dodecyl sulfate and polydimethylsiloxane is 10:2:0.5.
[0078] The preparation method of pretreated boron mud is as follows: soapberry powder and water are mixed at a ratio of 1:20, stirred at 90℃ and 80r / min for 20min, filtered and the filtrate is collected to obtain a second mixture for later use. The boron mud is dried, pulverized and passed through a 200-mesh sieve, and then added to the second mixture to obtain pretreated boron mud. The mass ratio of boron mud to the second mixture is 1:6.
[0079] The preparation method of functional additives includes the following steps:
[0080] Step A: Mix triethanolamine and water at a mass ratio of 1:8 and stir for 10 minutes at 30°C and 60 r / min to obtain the first treatment agent;
[0081] Step B: Mix cellulose alkyl ether with water at a mass ratio of 0.5:10 to obtain the first mixture for later use. Mix water, anhydrous ethanol, silane coupling agent KH550, and nano silica to obtain the second mixture. Mix the first mixture and the second mixture at a mass ratio of 1:3 and stir at 40 r / min for 15 min to obtain the second treatment agent.
[0082] Step C: Mix straw ash with the first treatment agent at a mass ratio of 1:4, stir at 60℃ and 60r / min for 60min, filter and dry to obtain the treated straw ash;
[0083] Step D: Mix bamboo fiber with the second treatment agent, soak at 50°C for 4 hours, and dry to obtain treated bamboo fiber;
[0084] Step E: Mix the treated straw ash, treated bamboo fiber and water at a mass ratio of 1:3:10, stir at 70℃ and 50r / min for 60min, filter and retain the filter residue, and then wash and dry to obtain the functional additive.
[0085] The mass ratio of water, anhydrous ethanol, silane coupling agent KH550, and nano silica is 1:3:0.5:1.5.
[0086] A method for preparing ultra-high performance UHPC concrete in high-altitude and cold regions, characterized by comprising the following steps:
[0087] Step 1: Add aluminate cement, additives, and quartz sand into a mixer and dry mix for 3 minutes at a speed of 40 r / min to obtain the first mixture;
[0088] Step 2: Add water and polycarboxylate superplasticizer to the first mixture, stir for 8 minutes at a speed of 50 r / min to obtain the second mixture;
[0089] Step 3: Add steel fibers and functional additives to the second mixture, stir for 15 minutes at a speed of 80 r / min to obtain concrete mixture;
[0090] Step 4: After pouring the concrete mixture into the mold, it is cured with high-temperature steam for 14 days to obtain ultra-high performance UHPC concrete for cold regions.
[0091] Comparative Example 1: The difference between this comparative example and Example 1 is that this comparative example does not contain any additives.
[0092] Comparative Example 2: The difference between this comparative example and Example 1 is that this comparative example does not contain functional additives.
[0093] Comparative Example 3 differs from Example 1 in that straw ash and bamboo fiber were not added during the preparation of the functional additives in this comparative example.
[0094] Performance testing: The concrete prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests, and the test data are recorded in the table below:
[0095] Table 1
[0096]
[0097] In the performance tests, the frost resistance test is conducted according to GB / T50082-2009, using the rapid freezing method. The relative dynamic elastic modulus of the concrete after freeze-thaw cycles is recorded as an evaluation index for frost resistance; the higher the value, the better the frost resistance. The compressive strength test is conducted according to GB / T50081-2019, testing the cubic compressive strength of the concrete after standard curing, reflecting the mechanical properties of the material. The higher the value, the stronger the compressive strength. The flexural strength test is conducted according to GB / T50081-2019, testing the flexural strength of the concrete, reflecting the material's crack resistance under temperature stress in cold regions. The higher the value, the stronger the crack resistance.
[0098] The additive is prepared by microwave pyrolysis of additive powder and pretreated boron mud. The cathode carbon blocks and silica fume in the additive powder are refined by ball milling and can form a micro-aggregate filling structure in the concrete matrix. After the pretreated boron mud is treated with soapberry powder, its active ingredients can react with cement hydration products to generate a stable hydration phase, which improves the density of the matrix. In Comparative Example 1, because it does not contain additives, the concrete lacks the filling effect of micro-aggregates and the reinforcing effect of hydration phase. During the freeze-thaw cycle, water can easily penetrate and generate freeze-thaw stress, resulting in a decrease in the relative dynamic elastic modulus. At the same time, the structural stability of cement hydration products is insufficient, and the compressive strength is greatly reduced due to the lack of support from the additives. The presence of additives optimizes the structure of the concrete matrix and makes the bond between the matrix and aggregates tighter.
[0099] The functional additives contain triethanolamine, which acts as a hydration accelerator, accelerating the early hydration of aluminate cement and rapidly forming a strength skeleton. Comparative Example 2, lacking functional additives, did not have triethanolamine to promote the hydration reaction of aluminate cement, resulting in a slower cement hydration rate and a loose structure of hydration products. Furthermore, the absence of straw ash and bamboo fiber acting on the cement matrix prevented the formation of a fiber-reinforced network and interface modification. Consequently, cracks in the concrete were prone to rapid development during freeze-thaw cycles, significantly reducing its frost resistance. Compressive and flexural strengths were also reduced due to the lack of multiple reinforcing effects. The combined effect of the functional additives achieved a synergistic effect of cement hydration promotion and fiber reinforcement, enhancing the frost resistance of ultra-high performance UHPC concrete in cold regions.
[0100] Straw ash and bamboo fiber are the core natural reinforcing components in the functional additives. After treatment with triethanolamine, the active sites on the surface of straw ash increase, allowing it to fully combine with cement hydration products. The resulting hydrated phase further enriches the matrix structure. After treatment with silane coupling agents and cellulose alkyl ethers, the surface hydrophilicity of bamboo fiber is improved, and its adhesion to the cement matrix is significantly enhanced. The three-dimensional fiber network formed in concrete can effectively bridge microcracks. When concrete is subjected to temperature stress or external forces, the fibers can absorb energy and prevent further crack propagation, achieving a toughening and strengthening effect. In Comparative Example 3, because the functional additives do not contain straw ash and bamboo fiber, the functional additives only retain the hydration promoting effect, losing the synergistic effect of straw ash activity enhancement and fiber toughening. The ability to inhibit internal cracks in concrete decreases, cracks are prone to develop during freeze-thaw cycles, and the freeze-thaw resistance is reduced. At the same time, the compressive and flexural strengths are significantly lower than those in the examples due to the lack of fiber support. The synergistic effect of straw ash and bamboo fiber plays a key role in improving the freeze-thaw resistance of ultra-high performance concrete (UHPC) in cold regions.
[0101] By comparing and analyzing the relevant data in the table, it can be seen that the concrete prepared by this invention not only has good frost resistance but also excellent compressive and flexural strength. This indicates that the ultra-high performance UHPC concrete for high-altitude and cold regions provided by this invention has a broader market prospect and is more suitable for widespread application.
[0102] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0103] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A high-performance UHPC concrete for high-altitude and cold regions, characterized in that, It is prepared from the following raw materials in parts by weight: 480-560 parts aluminate cement, 20-40 parts additives, 45-75 parts functional additives, 520-580 parts quartz sand, 70-80 parts steel fiber, 12-20 parts polycarboxylate superplasticizer, and 100-120 parts water. The additive raw materials include additive powder and pretreated boron mud; The preparation method of the additive powder includes the following steps: after crushing and cleaning the cathode carbon block, it is passed through a 100-mesh sieve, and the sieve material is collected to obtain coarse powder. The coarse powder is mixed with silica fume to obtain mixed powder. The mixed powder is placed in a ball mill, and 0.3-0.5% of the mass of the mixed powder is added to a first mixed liquid. The mixture is ground for 60-90 minutes and passed through a 100-200 mesh sieve to obtain the additive powder. The preparation method of the pretreated boron mud is as follows: soapberry powder and water are mixed at a ratio of 1:(10-20), stirred at 70-90℃ and 50-80r / min for 10-20min, and then filtered to obtain the filtrate, which is used as a second mixture. The boron mud is dried, pulverized and passed through a 100-200 mesh sieve, and then added to the second mixture to obtain the pretreated boron mud. The mass ratio of boron mud to the second mixture is 1:(3-6). The functional additives include triethanolamine, cellulose alkyl ethers, anhydrous ethanol, silane coupling agent KH550, nano silica, straw ash, and bamboo fiber. The preparation method of the first mixture includes the following steps: heating water to 40-50°C, adding sodium dodecyl sulfate and polydimethylsiloxane, stirring at 300-500 r / min for 15-20 min, and cooling to 23-25°C to obtain the first mixture, wherein the mass ratio of water, sodium dodecyl sulfate and polydimethylsiloxane is 10:(0.5-2):(0.1-0.5).
2. The ultra-high performance UHPC concrete for high-altitude and cold regions according to claim 1, characterized in that, The additive preparation method includes the following steps: mixing the additive powder with pretreated boron mud at a mass ratio of 1:(0.6-1.2), placing it in a microwave pyrolysis furnace, heating it to 500-600℃ at a heating rate of 10-15℃ / min under a nitrogen atmosphere, holding it at that temperature for 40-60min, cooling it to 20-25℃ with the furnace, and pulverizing it through a 100-200 mesh sieve to obtain the additive.
3. The ultra-high performance UHPC concrete for high-altitude and cold regions according to claim 1, characterized in that, The mass ratio of the powder coarse material to silica fume is 1:(0.6-1.2).
4. The ultra-high performance UHPC concrete for high-altitude and cold regions according to claim 1, characterized in that, The preparation method of the functional additive includes the following steps: Step A: Mix triethanolamine and water at a mass ratio of 1:(5-8) and stir for 5-10 minutes at 20-30℃ and 40-60r / min to obtain the first treatment agent; Step B: Mix cellulose alkyl ether with water at a mass ratio of (0.1-0.5):(8-10) to obtain a first mixture for later use. Mix water, anhydrous ethanol, silane coupling agent KH550, and nano silica to obtain a second mixture. Mix the first mixture and the second mixture at a mass ratio of 1:(1-3) and stir at 20-40 r / min for 10-15 min to obtain the second treatment agent. Step C: Mix straw ash with the first treatment agent at a mass ratio of 1:(2-4), stir for 30-60 min at 40-60℃ and 40-60 r / min, filter and dry to obtain the treated straw ash; Step D: Mix bamboo fiber with the second treatment agent, soak at 40-50℃ for 2-4 hours, and dry to obtain treated bamboo fiber; Step E: Mix the treated straw ash, treated bamboo fiber and water, stir at 50-70℃ and 30-50 r / min for 30-60 min, filter and retain the filter residue, wash and dry to obtain the functional additive.
5. The ultra-high performance UHPC concrete for high-altitude and cold regions according to claim 4, characterized in that, The mass ratio of water, anhydrous ethanol, silane coupling agent KH550, and nano silica is 1:3:(0.25-0.5):(0.8-1.5).
6. The ultra-high performance UHPC concrete for high-altitude and cold regions according to claim 4, characterized in that, The mass ratio of the treated straw ash, the treated bamboo fiber and water is 1:(2-3):(8-10).
7. A method for preparing ultra-high performance UHPC concrete for high-altitude and cold regions as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Add aluminate cement, additives, and quartz sand into a mixer and dry mix for 2-3 minutes at a speed of 30-40 r / min to obtain the first mixture; Step 2: Add water and polycarboxylate superplasticizer to the first mixture, stir for 5-8 minutes at a speed of 40-50 r / min to obtain the second mixture; Step 3: Add steel fibers and functional additives to the second mixture, stir for 10-15 minutes at a speed of 50-80 r / min to obtain concrete mixture; Step 4: After pouring the concrete mixture into the mold, it is cured with high-temperature steam for 14 days to obtain ultra-high performance UHPC concrete for cold regions.