An ultra-high performance tungsten tailings concrete and a preparation method thereof
By using tungsten tailings to replace natural river sand in ultra-high performance concrete, and adding appropriate amounts of silica fume and steel fibers, the problem that tungsten tailings cannot be used to prepare ultra-high performance concrete in existing technologies has been solved, realizing resource utilization and performance improvement, and reducing environmental impact.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUNAN UNIV
- Filing Date
- 2026-04-10
- Publication Date
- 2026-06-09
AI Technical Summary
Existing technologies lack the ability to synergistically blend tungsten tailings with high-volume silica fume and specialized steel fibers, making it impossible to prepare ultra-high-performance concrete. This results in low matrix density and poor toughness, and the overuse of natural aggregates exacerbates resource and environmental conflicts.
An improved concrete mixing process was adopted, which involved adding steel fibers, using tungsten tailings to replace natural river sand, and adding appropriate amounts of silica fume and other materials to prepare ultra-high performance concrete, ensuring uniform mixing of materials and optimized particle size distribution.
It achieves efficient resource utilization of tungsten tailings, improves the workability and mechanical properties of ultra-high performance concrete, reduces cement consumption, reduces environmental pollution and resource shortages, and has excellent comprehensive performance.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of building materials technology, specifically to an ultra-high performance concrete (UHPC) prepared using tungsten tailings and its preparation method. Background Technology
[0002] Ultra-high performance concrete (UHPC) is an innovative cement-based composite material whose main components include cement, mineral admixtures, fine aggregates, high-strength short fibers, and water-reducing agents. Due to its ultra-high strength, high toughness, and excellent durability, this material has been widely used in long-span bridges, national defense facilities, complex structures, and marine construction. After more than 20 years of development, UHPC has made significant progress in design, preparation, performance, and engineering applications. In the hybrid design of UHPC, to achieve a good packing structure, a large amount of cement is usually required as a binder, and high-quality quartz sand is used as aggregate, with the aggregate accounting for nearly half of the total mass. However, quartz sand resources are unevenly distributed domestically, and its production process is complex and costly. Furthermore, the mining of quartz sand can damage the local natural environment. Therefore, river sand, due to its lower cost, has gradually been used as an alternative to quartz sand aggregate in traditional UHPC and has been widely applied. However, as a finite and non-renewable natural resource, the over-exploitation of river sand has caused serious damage to the river's ecological environment. With increasing awareness of ecological protection, many regions have implemented strict sand mining policies and control measures, resulting in significant restrictions on river sand supply. Therefore, researching low-cost, green, and low-carbon alternative aggregates to replace quartz sand and natural river sand in UHPC is of great practical significance.
[0003] Tungsten is a crucial non-ferrous metal widely used in electronic equipment, military armor-piercing projectiles, and drill bits, among other industries. my country, as the country with the world's richest tungsten resources, has proven reserves of approximately 1.8 million tons, ranking first globally. However, in recent years, due to rapid tungsten mining, reserves have been continuously decreasing, while the discharge of tungsten tailings has been increasing year by year. Statistics show that China produces over 600,000 tons of tungsten tailings annually, with a cumulative stockpile approaching 16 million tons. However, the long-term accumulation of tailings not only occupies significant land resources but may also trigger secondary geological disasters. Furthermore, tailings release large amounts of toxic heavy metals during weathering, posing a serious threat to the ecosystem. Therefore, finding effective methods for the large-scale utilization of tailings has become an urgent priority.
[0004] Existing technologies have attempted to apply tungsten tailings to ordinary concrete, but these methods simply replace river sand with ordinary aggregates without precise control over the gradation of the tungsten tailings or achieving a synergistic ratio with silica fume and steel fibers. Therefore, they cannot be applied to ultra-high performance concrete (UHPC). Furthermore, in current UHPC preparation processes, insufficient silica fume content or inappropriate steel fiber selection leads to low matrix density and poor toughness, while the overuse of natural aggregates further exacerbates resource and environmental conflicts. Therefore, existing technologies lack a method for producing ultra-high performance tungsten tailings concrete that synergistically combines tungsten tailings with specific gradations, high silica fume content, and specialized steel fibers, with a precisely controllable preparation process. This approach would both realize the resource utilization of solid waste and ensure the ultra-high mechanical and workability of UHPC. Patent content
[0005] This invention provides an ultra-high performance concrete prepared using tungsten tailings to solve the aforementioned problems in existing technologies. Utilizing readily available materials and industrial solid waste, and employing an improved concrete mixing process, the invention overcomes the brittleness and other drawbacks of ultra-high performance concrete by incorporating steel fibers, thereby producing ultra-high performance tungsten tailings concrete with excellent comprehensive properties.
[0006] The technical solution adopted by this invention to solve its technical problem is an ultra-high performance concrete prepared using tungsten tailings, which is composed of the following components: 650~750kg of cement, 170~190kg of water, 670~730kg of river sand, 270~330kg of tungsten tailings, 80~120kg of fly ash, 180~220kg of silica fume, 145~155kg of steel fiber, and 20~30kg of water-reducing agent.
[0007] Preferably, the ultra-high performance tungsten tailings concrete contains the following amounts of materials per cubic meter of concrete: 650-750 kg of cement, 170-190 kg of water, 670-730 kg of river sand, 270-330 kg of tungsten tailings, 80-120 kg of fly ash, 180-220 kg of silica fume, 145-155 kg of steel fiber, and 20-30 kg of water-reducing agent.
[0008] More preferably, the cement is P.O42.5 grade ordinary Portland cement with good compatibility with polycarboxylate superplasticizer;
[0009] The natural river sand is natural river sand with a particle size of less than 1.18 mm that conforms to GB / T 14684-2001.
[0010] The fly ash is Class I fly ash conforming to GB / T18736-2002;
[0011] The silica fume is conforming to GB / T 18736-2002 and has a specific surface area greater than 18000 m². 2 / kg;
[0012] The water-reducing agent is a polycarboxylate-based standard high-performance water-reducing agent conforming to GB 8076-2008, with a water reduction rate greater than 22%.
[0013] The present invention also provides a method for preparing the ultra-high performance tungsten tailings concrete, comprising the following steps:
[0014] (1) Weigh each raw material accurately according to the experimental mix ratio. First, dry mix the cementitious material and aggregate for 4 minutes to ensure that the dry material is mixed evenly.
[0015] (2) After starting the forced mixer, slowly add the pre-mixed water and water-reducing agent to the mixer while stirring, and continue stirring for 6 minutes;
[0016] (3) When the mixture gradually reaches the target fluidity, the fiber should be added in several batches at a slower speed. After all the fiber has been added, continue stirring for about 3 minutes to ensure that the fiber is fully and evenly distributed in the mixture;
[0017] (4) Immediately after mixing, begin casting the specimen, pouring gradually from one side of the mold. After casting, gently tap the side wall of the mold with a rubber mallet to remove air bubbles from the mixture. Then place the mold on a vibrating table for about 10-15 seconds to further remove residual gas and increase density.
[0018] This invention utilizes tungsten tailings sand to replace natural river sand in the preparation of ultra-high performance concrete (UHPC). This not only reduces the amount of traditional natural aggregate used and alleviates resource shortages, but also reduces the environmental remediation costs associated with tailings accumulation. It promotes the development of the industrial solid waste resource utilization chain, enhances the added value of tailings, and contributes to the construction of a circular economy. The numerous fine particles in the tungsten tailings sand can fully exert their filling effect, which is beneficial for improving the pore structure of UHPC, thereby improving the workability and mechanical properties of the ultra-high performance concrete.
[0019] By adopting the above technical solution, the construction method of the present invention has the following advantages:
[0020] (1) The compressive strength, flexural strength and other mechanical properties of ultra-high performance concrete are guaranteed by adopting a reasonable amount of tungsten tailings. A large number of experimental studies have shown that the addition of an appropriate amount of tailings sand can improve the workability, compressive strength and splitting tensile strength of ultra-high performance concrete. They believe that this is because tailings sand can optimize the particle size distribution of aggregates and optimize the pore structure of the matrix.
[0021] (2) It realizes the efficient resource utilization of tungsten tailings solid waste and reduces the risk of pollution to land and water bodies caused by tailings accumulation.
[0022] (3) By reducing the amount of cement used, CO2 emissions can be reduced, the ecological damage caused by the over-mining of natural sand can be alleviated, and a feasible path can be provided for the low-carbon development of the construction industry. Detailed Implementation
[0023] The technical solution of the present invention will be clearly and completely described below with the aid of embodiments. Obviously, the described embodiments are only some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application.
[0024] Raw materials:
[0025] 1. Cement
[0026] The cement is ordinary Portland cement, with a strength grade of PO 42.5 and a density of 3100 kg / m³. 3 Upon inspection, all technical indicators of the cement meet the requirements of GB 175-2007 "General Portland Cement Quality Standard": specific surface area not less than 300 m². 2 / kg, loss on ignition not greater than 5%, SO3 content not greater than 3.5%, MgO content not greater than 5%, Cl - The content is not greater than 0.06%, the alkali content is not greater than 0.6%, the initial setting time is not less than 45 min, the final setting time is not greater than 600 min, the 3-day strength is not less than 17 MPa, and the 28-day strength is not less than 42.5 MPa.
[0027] Before use, a compatibility test was conducted between the two and a standard polycarboxylate superplasticizer. The test method adopted the method in the current building materials industry standard "Test Method for Compatibility of Cement and Superplasticizer" JC / T 1083-2008, and it was finally determined that the two were compatible.
[0028] 2.Fine aggregate
[0029] The fine aggregate is natural river sand, which is fine sand with an apparent density of 2730 kg / m³. 3 The sand has a mud lump content of 0.1%, a mud content of 0.6%, a particle size controlled below 1.18mm, and continuous gradation, conforming to the standard GB / T 14684-2001. Testing shows that the sand quality meets the standards for high-quality sand specified in the current building materials industry standard JC / T 52-2006 "Standard for Quality and Testing Methods of Sand and Stone for Ordinary Concrete" and the national standard GB / T 14684-2001 "Sand for Construction".
[0030] 3. Fly ash
[0031] The fly ash is Grade I fly ash, and its quality meets the requirements of relevant standards such as the national standard GB / T1596-2017 "Fly Ash for Cement and Concrete".
[0032] 4. Water
[0033] The water is tap water, and its quality meets the requirements of the national standard "Standard for Water Used in Concrete" JGJ63-2006: pH value not less than 4.5, insoluble content not more than 2000 mg / L, soluble content not more than 5000 mg / L, and Cl... - The content is not greater than 1000 mg / L, SO4 2- The content is not greater than 2000 mg / L, and the alkali content is not greater than 1500 mg / L.
[0034] 5. Silica ash
[0035] Its apparent density is 2200 kg / m³ 3 Its quality meets the requirements of relevant standards such as the national standard "Mineral Admixtures for High-Strength and High-Performance Concrete" GB / T 18736-2002: loss on ignition not greater than 6%, SiO2 content not less than 85%, chloride ion content not greater than 0.02%, moisture content not greater than 3%, and specific surface area not less than 15000 m². 2 / kg, water requirement ratio not greater than 125%, activity index (28d) not less than 85%.
[0036] 6. High-efficiency water-reducing agent
[0037] The standard high-performance water-reducing agent based on polycarboxylate is used, with an apparent density of 1070 kg / m³. 3 The water reduction rate is greater than 22%, the chloride ion content is not greater than 0.6%, the sodium sulfate content is not greater than 5%, the alkali content is not greater than 10%, the formaldehyde content is not greater than 0.05%, the gas content is not greater than 6%, and the pH value is between 6 and 7. Its quality meets the requirements of the current national standard "Concrete Admixtures" GB8076-2008 and other relevant standards.
[0038] The present application will be further described in detail below with reference to the embodiments.
[0039] Example 1
[0040] In this embodiment of ultra-high performance tungsten tailings concrete, the proportions of each component in the ultra-high performance tungsten tailings concrete, calculated based on the required mass per unit volume of concrete, are as follows: the amount of each material per cubic meter of concrete is as follows: cement 700kg, water 180kg, river sand 700kg, tungsten tailings 300kg, fly ash 100kg, silica fume 200kg, steel fiber 150kg, and water-reducing agent 25kg.
[0041] The preparation and maintenance steps are as follows:
[0042] (1) Weigh each raw material accurately according to the experimental mix proportion. First, pre-dry mix the cementitious material and aggregate for 4 minutes to ensure that the dry material is mixed evenly. After starting the forced mixer, slowly add the pre-mixed water and water-reducing agent to the mixer while stirring for 6 minutes.
[0043] (2) When the mixture gradually reaches the target fluidity, the fiber should be added in several batches at a slower speed. After all the fiber has been added, continue stirring for about 3 minutes to ensure that the fiber is fully and evenly distributed in the mixture;
[0044] (3) Immediately after mixing, begin casting the specimen, pouring gradually from one side of the mold. After casting, gently tap the side wall of the mold with a rubber mallet to remove air bubbles from the mixture. Then place the mold on a vibrating table for about 10-15 seconds to further remove residual gas and improve density;
[0045] (4) After smoothing the specimen, cover the surface of the specimen with plastic film. After the specimen has been left to stand for 24 hours, remove the mold and place it in a standard curing room to cure until the specified age.
[0046] Example 2
[0047] In this embodiment, the ultra-high performance tungsten tailings concrete has the following proportions of each component calculated based on the mass required per unit volume of concrete: 650 kg cement, 180 kg water, 670 kg river sand, 330 kg tungsten tailings, 120 kg fly ash, 180 kg silica fume, 145 kg steel fiber, and 30 kg water-reducing agent.
[0048] The preparation and maintenance steps are the same as in Example 1.
[0049] Example 3
[0050] In this embodiment, the ultra-high performance tungsten tailings concrete has the following proportions of each component calculated based on the mass required per unit volume of concrete: cement 750kg, water 185kg, river sand 730kg, tungsten tailings 270kg, fly ash 100kg, silica fume 200kg, steel fiber 155kg, and water-reducing agent 25kg.
[0051] The preparation and maintenance steps are the same as in Example 1.
[0052] Example 4
[0053] In this embodiment, the ultra-high performance tungsten tailings concrete has the following proportions of each component calculated based on the mass required per unit volume of concrete: cement 720kg, water 175kg, river sand 710kg, tungsten tailings 310kg, fly ash 90kg, silica fume 220kg, steel fiber 150kg, and water-reducing agent 25kg.
[0054] The preparation and maintenance steps are the same as in Example 1.
[0055] Example 5
[0056] In this embodiment, the ultra-high performance tungsten tailings concrete has the following proportions of each component calculated based on the mass required per unit volume of concrete: 680 kg cement, 182 kg water, 690 kg river sand, 290 kg tungsten tailings, 80 kg fly ash, 190 kg silica fume, 150 kg steel fiber, and 25 kg water-reducing agent.
[0057] The preparation and maintenance steps are the same as in Example 1.
[0058] Comparative Example 1 (without tungsten tailings, replaced by river sand)
[0059] In this embodiment, the ultra-high performance tungsten tailings concrete has the following proportions of each component calculated based on the mass required per unit volume of concrete: 700 kg cement, 180 kg water, 1000 kg river sand (replacing 300 kg tungsten tailings), 100 kg fly ash, 200 kg silica fume, 150 kg steel fiber, and 25 kg water-reducing agent.
[0060] The preparation and maintenance steps are the same as in Example 1.
[0061] Comparative Example 2 (Basalt Fiber Replacing Steel Fiber)
[0062] In this embodiment, the ultra-high performance tungsten tailings concrete has the following proportions of each component calculated based on the mass required per unit volume of concrete: 700 kg cement, 180 kg water, 700 kg river sand, 300 kg tungsten tailings, 100 kg fly ash, 200 kg silica fume, 150 kg basalt fiber, and 25 kg water-reducing agent.
[0063] The preparation and maintenance steps are the same as in Example 1.
[0064] Comparative Example 3 (insufficient silica fume content, below the patent scope).
[0065] This embodiment of ultra-high performance tungsten tailings concrete has the following component proportions calculated based on the required mass per unit volume of concrete: cement 700kg, water 180kg, river sand 700kg, tungsten tailings 300kg, fly ash 100kg, silica fume 150kg, steel fiber 150kg, and water-reducing agent 25kg. The preparation and curing steps are the same as in Example 1.
[0066]
[0067] The test results are shown in the table below:
[0068] The 28-day compressive strength, splitting tensile strength, and flexural strength of Comparative Example 1 (without tungsten tailings) decreased by 10.3%, 19.6%, and 19.4% respectively compared to Example 1, and the fluidity decreased by 8.6%. This proves that the tungsten tailings content of 270~330kg / m³ in the patent can optimize the aggregate gradation and improve the matrix density through the particle filling effect, thereby realizing the utilization of industrial solid waste and ensuring performance.
[0069] The mechanical properties of Comparative Example 2 (basalt fiber instead of steel fiber) deteriorated across the board, with compressive strength decreasing by 15.5%, splitting tensile strength decreasing by 29.0%, and flexural strength decreasing by 26.8% compared to Example 1. This verifies the rationality of the patent's choice of steel fiber (145~155kg / m³), whose high tensile strength and interfacial adhesion are key to achieving C120 grade concrete.
[0070] Comparative Example 3 (silica fume 150 kg / m³, below the patent lower limit) showed a 12.6% decrease in compressive strength and a 22.5% decrease in splitting tensile strength compared to Patent Example 1, indicating that silica fume concentrations of 180-220 kg / m³ are appropriate. 3 The appropriate dosage range can fully utilize the pozzolanic effect and filling function; if it is too low, it cannot meet the requirements of ultra-high performance.
[0071] The core technical framework of this invention is the three-level synergistic effect of "tungsten tailings resource utilization + steel fiber reinforcement + silica fume". It highlights the universality of the patented formula in maintaining the C120 strength grade and adaptability to construction even with parameter fine-tuning. At the same time, it clarifies the triple value of the patented technology of "solid waste resource utilization - ultra-high strength - economic and environmental protection". Its mechanical properties are improved by an average of 10% to 30% compared with the comparative scheme, which further consolidates the foundation of the patented technology and provides sufficient experimental support for engineering transformation and promotion.
[0072] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A high-performance tungsten tailings concrete, characterized in that, The concrete per cubic meter includes the following raw materials and quantities: Cement 650~750kg; 170-190 kg of water; 670~730 kg of river sand; Tungsten tailings 270~330kg; 80-120 kg of fly ash; 180~220kg of silica fume; 145~155 kg of steel fiber; Water-reducing agent 20~30kg; The river sand is natural fine sand with a particle size of less than 1.18 mm and conforms to the GB / T14684-2001 standard; The sieve residue percentages of the tungsten tailings meet the following requirements: 0% for 1.18mm sieve, 3.70% for 0.60mm sieve, 18.11% for 0.30mm sieve, 21.99% for 0.15mm sieve, 36.95% for 0.075mm sieve, and 19.25% for <0.075mm sieve. The sieve testing is conducted in accordance with GB / T14684-2001.
2. The ultra-high performance tungsten tailings concrete according to claim 1, characterized in that, The cement is P.O42.5 grade ordinary Portland cement, and its compatibility with polycarboxylate superplasticizer meets the requirements of JC / T1083-2008 standard.
3. The ultra-high performance tungsten tailings concrete according to claim 1, characterized in that, The fly ash is Class I fly ash, conforming to GB / T1596-2017 standard; the silica fume conforms to GB / T18736-2002 standard and has a specific surface area greater than 18000 m². 2 / kg, with SiO2 content not less than 85%.
4. The ultra-high performance tungsten tailings concrete according to claim 1, characterized in that, The water-reducing agent is a standard high-performance polycarboxylate-based water-reducing agent that conforms to GB8076-2008 standard and has a water reduction rate greater than 22%.
5. The ultra-high performance tungsten tailings concrete according to claim 1, characterized in that, The steel fibers are straight or hooked steel fibers with an aspect ratio of 40 to 60, a tensile strength of not less than 2800 MPa, a diameter of 0.1 to 0.2 mm, and a length of 6 to 12 mm.
6. The ultra-high performance tungsten tailings concrete according to any one of claims 1 to 5, characterized in that, The preferred raw material dosage per cubic meter of the concrete is: 700 kg of cement, 180 kg of water, 700 kg of river sand, 300 kg of tungsten tailings, 100 kg of fly ash, 200 kg of silica fume, 150 kg of steel fiber, and 25 kg of water-reducing agent.
7. A method for preparing ultra-high performance tungsten tailings concrete according to any one of claims 1 to 6, characterized in that, Includes the following steps: 1) Accurately weigh each raw material according to the mix proportion, and put the cementitious material composed of cement, fly ash and silica fume and the aggregate composed of river sand and tungsten tailings into a planetary forced mixer. Pre-dry mix at a speed of 300~400r / min for 4 minutes to ensure that the dry materials are mixed evenly. 2) Keep the mixer speed at 300~400r / min, and slowly add the pre-mixed water and water-reducing agent while stirring, and continue stirring for 6 minutes; 3) When the fluidity of the mixture reaches 240~270mm (target fluidity), add steel fibers in 2~3 portions at a low speed of 100~200r / min, with an interval of 30s between each addition. After all the steel fibers are added, resume stirring at 300~400r / min for 3 minutes to ensure uniform distribution of the steel fibers. 4) After the fluidity test is qualified, pour the mixture gradually from one side of the mold. After pouring, tap the side wall of the mold with a rubber mallet to release air. Then place the mold on the vibration table and vibrate at a frequency of 50~60Hz for 10~15s to remove residual gas and improve the density. 5) Smooth the surface of the specimen, cover it completely with plastic film and seal it. After standing for 24 hours in an environment of 20±2℃ and relative humidity ≥50%, remove the mold and place the specimen in a standard curing room with a temperature of 20±2℃ and relative humidity ≥95% to cure until the specified age.