A small prefabricated component for highway engineering based on modified gold tailings and its preparation method

Abstract

The present invention relates to the technical field of highway engineering materials, specifically to a small prefabricated component for highway engineering based on modified gold tailings and a method for preparing the same. By modifying the gold tailings, the present invention further reduces the porosity within the prefabricated component, achieving higher strength while significantly improving frost resistance and salt corrosion resistance. The prefabricated component is suitable for use in highway engineering projects in cold or coastal regions.

Description

Technical Field

[0001] The present invention relates to the technical field of highway engineering materials, and in particular to a small prefabricated component for highway engineering based on modified gold tailings and a preparation method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] In highway construction, small prefabricated components (such as curbs, ditch covers, slope protection blocks, isolation piers, and road marking blocks) are often constructed using ordinary C30 concrete. While this concrete is low-cost and readily available, it suffers from cracking and poor salt-freeze resistance. Particularly in cold regions or coastal saline environments, salt ion corrosion and freeze-thaw cycles often cause surface peeling, chipping, and even structural failure in these components, necessitating frequent repairs and significantly increasing project costs. Furthermore, traditional concrete relies on cement and crushed stone, requiring significant extraction of natural resources and exacerbating ecological pressures.

[0004] At present, there are two main measures to improve the salt-freeze resistance of concrete: one is the external isolation method, which is spraying or impregnating sealing materials such as water glass. This method can effectively block open pores, reduce the permeability of chloride ions, and improve salt-freeze resistance, but the preparation process is complicated and the cost increases; the other is the internal pore structure adjustment method, which is adding ultrafine powder to the concrete component materials to fill the capillaries, or introducing bubbles to block the capillaries; however, common ultrafine powders are silica fume, graphene, etc., which are expensive and greatly increase the preparation cost; the introduction of bubbles can block the connectivity of the capillaries and reduce the water absorption rate, but it has an adverse effect on the strength of the material.

[0005] Gold tailings, the solid waste produced after gold ores are beneficiated or extracted to recover gold or other useful components, are suitable for use in the preparation of engineering materials due to their fine particle size, high specific surface area, and high silicon and aluminum content. However, direct use of gold tailings in prefabricated highway components, due to their fine particle size, results in increased water demand and porosity, thus failing to improve salt freeze resistance. Summary of the Invention

[0006] To overcome these issues, the present invention provides a small prefabricated component for highway engineering based on modified gold tailings and a method for its preparation. By modifying the gold tailings, the present invention further reduces the porosity within the prefabricated component, achieving higher strength while significantly improving its frost and salt corrosion resistance. This makes it suitable for the production of small prefabricated components for highway engineering in cold or coastal regions.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] The first aspect of the present invention provides a small prefabricated component for highway engineering based on modified gold tailings, the raw materials comprising, by weight:

[0009] 52-64 parts of modified gold tailings, 5-9 parts of activator, 26-32 parts of active mineral admixture, 8-15 parts of epoxy resin, 0.5-2 parts of water reducer, 0.5-1 parts of expansion agent, 0.5-1 parts of air entraining agent, 0.1-0.5 parts of fiber and 10-20 parts of water;

[0010] The preparation method of the modified gold tailings comprises the following steps:

[0011] Diethylene glycol butyl ether acetate, hexaethyl phosphoramidite and nano-montmorillonite are sequentially added to the calcium nitrite aqueous solution and mixed evenly to obtain a modified solution;

[0012] The gold tailings are immersed in a modification liquid, stirred, taken out, dried and solidified to obtain modified gold tailings;

[0013] The mass ratio of calcium nitrite, nano-montmorillonite, diethylene glycol butyl ether acetate and hexaethyl phosphoramidite is (1~3):(5~10):(2~4):(1~2).

[0014] Within the limited mass ratio range, calcium nitrite, nano-montmorillonite, diethylene glycol butyl ether acetate and hexaethyl phosphoramidite have the best modification effect on gold tailings.

[0015] In one or more embodiments, the concentration (mass percentage) of the calcium nitrite aqueous solution is 28-40%, preferably 30%. The calcium nitrite aqueous solution is alkaline, and the alkaline environment promotes the dispersion of montmorillonite and the adsorption of Ca 2+ , forming a dense coating layer, reducing the porosity of gold tailings. At the same time, calcium nitrite has strong oxidizing properties and can form a passivation film on the surface of gold tailings, inhibiting the oxidation reaction of metal ions and forming a stable composite oxide to form a physical barrier.

[0016] In one or more embodiments, the gold tailings are immersed in the modification solution for 20 to 30 minutes. Within this limited time, the various modifiers can fully react with the gold tailings to obtain modified gold tailings.

[0017] In one or more embodiments, the gold tailings particle size ranges from 75 to 600 μm. Too fine a particle size results in excessive water demand for concrete, making the mix viscous and difficult to form into small prefabricated components. Conversely, too large a particle size increases the contact area between the cementitious material and the gold tailings particles, creating pores on the contact surface and increasing the likelihood of ion corrosion.

[0018] In one or more embodiments, the nano-montmorillonite has an average platelet thickness of less than 25 nm and a montmorillonite content greater than 95%.

[0019] In one or more embodiments, the activator is composed of red mud, industrial by-product gypsum and carbide slag, and the mass ratio of the red mud, industrial by-product gypsum and carbide slag is (10-15): (5-10): (2-5). The red mud and carbide slag are strongly alkaline and together with the industrial by-product gypsum, they create an alkaline environment in which the stable silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron network structures in the active admixture are oxidized by alkaline ions (such as OH). - ) are destroyed, depolymerized, and release active silicon, aluminum and other elements.

[0020] Preferably, the red mud is Bayer red mud with a pH value of 7 to 8.5;

[0021] Preferably, the industrial by-product gypsum is fluorgypsum, and the CaSO4 content is not less than 85%;

[0022] Preferably, the Ca(OH)2 content in carbide slag is greater than 85%.

[0023] In one or more embodiments, the active mineral admixture is composed of blast furnace slag powder, coal gangue powder, silica fume, steel slag powder, high-grade terrestrial ore, recycled aggregate fine powder and incineration fly ash; the mass ratio of the blast furnace slag powder, coal gangue powder, silica fume, steel slag powder, high-grade terrestrial ore, recycled aggregate fine powder and incineration fly ash is (40~55):(15~20):(1~3):(5~10):(3~8):(5~10):(10~15).

[0024] Preferably, the blast furnace slag is of grade S70 or above, and the SiO2+CaO content is greater than 70%;

[0025] Preferably, the coal gangue powder is decarbonized coal gangue powder that has been treated with microbial mineralization;

[0026] Preferably, the particle size of the silica fume is less than 1 μm and the SiO2 content is greater than 80%;

[0027] Preferably, the SiO2+CaO+Al2O3 content in the steel slag powder is greater than 60%;

[0028] Preferably, the SiO2+CaO+Al2O3 content in the high-altitude territory is greater than 65%;

[0029] Preferably, the recycled aggregate fine powder SiO2+CaO+Al2O3 content is greater than 50%;

[0030] Preferably, the SiO2+CaO+Al2O3 content of the incineration fly ash is greater than 70%.

[0031] The SiO2+CaO+Al2O3 content in steel slag powder, high-grade territorial steel, recycled aggregate powder and incineration fly ash in active mineral admixtures is limited here to ensure that these solid waste raw materials have a sufficient total amount of active oxides to support their basic gelling activity and strength development potential, while indirectly controlling the content of impurities and inert components, ensuring the stability of the hydration reaction, the consistency of material properties and the mechanical and durability properties of the final product, and realizing the efficient and safe utilization of solid waste resources.

[0032] In one or more embodiments, the epoxy resin is a water-based epoxy resin with a solids content of 99% and an epoxy equivalent weight of 190-220 g / eq. This high solids content ensures both film-forming properties during construction and environmental friendliness (minimizing shrinkage cracking and reducing VOCs). Precise control of the epoxy equivalent weight optimizes crosslinking density and reactivity, ensuring the formation of a high-strength, chemically resistant, and stable three-dimensional network structure after curing. Ultimately, this achieves a synergistic improvement in material performance, construction reliability, and environmental benefits.

[0033] In one or more embodiments, the water reducer is a polycarboxylate-based water reducer with a water reduction rate greater than 40%. This highly efficient dispersion significantly reduces the water-to-binder ratio (>40% water reduction), simultaneously achieving a triple boost in concrete performance: optimized fluidity ensures workability, a low water-to-binder ratio drives increased strength and density, and cementitious materials are conserved to reduce carbon emissions. Ultimately, this ultra-high water reduction efficiency supports the coordinated development of high-performance concrete's strength, durability, and low carbonization.

[0034] Preferably, the polycarboxylate water reducer is specifically selected from one of the PCA®-I series and PCA®-9 series.

[0035] In one or more embodiments, the expansion agent is a calcium aluminum sulfate expansion agent.

[0036] Preferably, the calcium aluminum sulfate expansion agent is UEA-1 expansion agent.

[0037] In one or more embodiments, the air-entraining agent is an alkylbenzene sulfonate air-entraining agent.

[0038] Preferably, the alkylbenzene sulfonate air-entraining agent is selected from sodium dodecylbenzene sulfonate and sodium dodecyl sulfate.

[0039] In one or more embodiments, the fibers include nanoscale fibers and millimeter-scale fibers, with the mass ratio of the nanoscale fibers to the millimeter-scale fibers being (1-2):(5-7). The nanoscale fibers can fill the tiny pores within the concrete, enhancing the material's compactness, while the millimeter-scale fibers can provide a reinforcement effect over a wider range. The combination of the two can more comprehensively enhance the overall performance of concrete at different scales, and the multi-scale fibers can reduce shrinkage cracking during curing.

[0040] Preferably, the nanoscale fiber is one of carbon nanotube fiber and graphene fiber, and has a particle size of 10-30 nm;

[0041] Preferably, the millimeter-scale fiber is one of polyethylene fiber, polypropylene fiber, and steel fiber, and has a particle size of 2 to 4 mm.

[0042] The second aspect of the present invention provides a method for preparing a small prefabricated component for highway engineering based on modified gold tailings according to the first aspect, comprising the following steps:

[0043] (1) The activator and the active mineral admixture are mixed and ball-milled to obtain a powder mixture;

[0044] (2) uniformly mixing the modified gold tailings, powder mixture, expander, air entraining agent and fiber to obtain a solid mixture;

[0045] (3) adding all the water, epoxy resin and water reducing agent to the solid mixture and mixing them evenly to obtain a slurry for small prefabricated components for highway engineering based on modified gold tailings;

[0046] (4) Pour the slurry of small prefabricated components for highway engineering based on modified gold tailings into a mold to obtain small prefabricated components for highway engineering based on modified gold tailings.

[0047] In one or more embodiments, in step (1), during the ball milling process, the ball-to-material ratio is (2:1) to (5:1), the ball milling time is 2 to 3 minutes, and the rotation speed is 400 to 500 r / min. Under these ball milling conditions, the specific surface area of ​​the powder mixture after milling can be guaranteed to be 350 to 450 kg / m 2 , while reducing energy consumption and metal consumption.

[0048] The beneficial effects of the present invention are:

[0049] (1) The present invention provides a small prefabricated component for highway engineering based on modified gold tailings and a preparation method thereof. In the present invention, the porosity inside the prefabricated component is further reduced by modifying the gold tailings, and while forming a higher strength, the antifreeze and salt corrosion resistance are significantly improved. It is suitable for preparing small prefabricated components for highway engineering in cold areas or coastal areas. Specifically, the calcium nitrite aqueous solution is alkaline, and the alkaline environment promotes the dispersion of montmorillonite and the adsorption of Ca 2+ , forming a dense coating layer, reducing the porosity of gold tailings. At the same time, calcium nitrite has strong oxidizing properties and can form a passivation film on metals such as Fe and Al on the surface of gold tailings, inhibiting the oxidation reaction of metal ions, forming a stable composite oxide, and forming a physical barrier; the negative charge and active hydroxyl groups on the surface of nano-montmorillonite can adsorb Cl - 、SO4 2- The active admixtures, including blast furnace slag powder, coal gangue powder, silica fume, steel slag powder, high-alkaline ore, recycled aggregate powder, and incineration fly ash, provide abundant sources of silicon, aluminum, and calcium. Red mud and carbide slag are highly alkaline, and together with industrial by-product gypsum, they create an alkaline environment. In this environment, the stable silicon-oxygen tetrahedral and aluminum-oxygen tetrahedral networks in the active admixtures are disrupted by alkaline ions (such as OH⁻), causing them to depolymerize and release active silicon, aluminum, and other elements. The active ions and small molecular clusters released after depolymerization react with Ca 2+ The hydration reaction occurs, active silicon ions and Ca 2+ , OH⁻ react to form C~(A)~S~H gel, Al 3+ With Ca 2+ 、SO4 2-, OH⁻, etc., to form ettringite. These hydration products grow and intertwine, forming a three-dimensional network structure that tightly connects the modified gold tailings. In this process, new chemical bonds are continuously generated. The various chemical bonds in the C~(A)~S~H gel and the special crystal structure of ettringite give the material higher strength and stability, improving its ability to resist external damage. By adding an expansion agent, it reacts with an alkaline activator to produce a volume expansion product, which can be used to compensate for system shrinkage. By adding an air-entraining agent, a micro bubble buffer layer is formed inside small prefabricated components, improving the durability of concrete. By adding epoxy resin, nano-scale and micro-scale fibers, the microscopic voids inside the concrete can be filled to improve density, the interface strength can be enhanced, and a "nano-micro" dual crack-blocking system can be formed to achieve multi-scale reinforcement and toughening of concrete.

[0050] (2) The small prefabricated components for highway engineering based on modified gold tailings provided in the present invention are all made of general industrial solid waste. The environmental protection performance meets the requirements of various engineering uses, while alleviating the environmental pollution and land occupation problems caused by solid waste storage. DETAILED DESCRIPTION

[0051] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0052] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0053] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0054] In the following examples, the contents of each component in each composition are shown in Table 1.

[0055] Table 1 Chemical composition and content of each component

[0056]

[0057] The water-based epoxy resin is Baling Petrochemical Epoxy Resin CYDW-100 water-based resin bisphenol A type low-viscosity resin.

[0058] Polycarboxylate-based water reducers are PCA®-I series water reducers.

[0059] The calcium aluminum sulfate expansion agent is UEA-1 expansion agent.

[0060] The alkylbenzene sulfonate air entraining agent is sodium dodecylbenzene sulfonate.

[0061] Carbon nanotube fibers and graphene fibers are both commercially available and have a particle size of 15 nm.

[0062] The particle size of millimeter-scale fibers is 3 mm.

[0063] Example 1

[0064] (1) Preparation of modified gold tailings:

[0065] 30 parts of calcium nitrite were dissolved in 70 parts of water to form an alkaline solution (pH = 10.5), 60 parts of diethylene glycol butyl ether acetate, 15 parts of hexaethyl phosphoramidite, and 120 parts of nano-montmorillonite were added in sequence, and high-speed shear stirring (1300 rpm) was performed for 30 minutes to obtain a modified solution after mixing.

[0066] 52 parts of gold tailings were immersed in the modification solution and stirred continuously for 30 min. After being taken out, they were dried and solidified at 60 °C to obtain modified gold tailings.

[0067] (2) Small prefabricated components for highway engineering based on modified gold tailings, the raw materials include, by weight:

[0068] 52 parts of modified gold tailings, 5 parts of activator, 26 parts of active mineral admixture, 12 parts of epoxy resin, 0.9 parts of water reducer, 0.8 parts of expansion agent, 0.8 parts of air entraining agent, 0.5 parts of fiber and 13 parts of water.

[0069] In the activator, the mass ratio of red mud, industrial by-product gypsum and carbide slag is 12:8:3;

[0070] In the active mineral admixture, the mass ratio of blast furnace slag powder, coal gangue powder, silica fume, steel slag powder, high-grade territorial sand, recycled aggregate powder and incineration fly ash is 50:18:2:8:3:5:15;

[0071] Among the fibers, the nano-scale fibers are graphene fibers, the millimeter-scale fibers are polyethylene fibers, and the mass ratio of the nano-scale fibers to the millimeter-scale fibers is 1:6.

[0072] (3) The preparation method of small prefabricated components for highway engineering based on modified gold tailings is as follows:

[0073] The activator and the active mineral admixture were mixed and then ball-milled to obtain a powder mixture; during the ball-milling process, the ball-to-material ratio was 3:1, the ball-milling time was 3 min, and the rotation speed was 500 r / min.

[0074] Add the modified gold tailings, powder mixture, expansion agent, air entraining agent and fiber into the concrete mixer in sequence according to the designed ratio, stir at a speed of 45 r / min for 5 minutes, and obtain a solid mixture after mixing evenly;

[0075] All the water, epoxy resin and water reducing agent were added, stirred at a speed of 45 r / min for 10 minutes, and after mixing evenly, a slurry for small prefabricated components for highway engineering based on modified gold tailings was obtained;

[0076] The small-scale prefabricated component slurry for highway engineering based on modified gold tailings is poured into a mold to obtain the small-scale prefabricated component for highway engineering based on modified gold tailings.

[0077] Example 2

[0078] (1) Preparation of modified gold tailings:

[0079] 30 parts of calcium nitrite were dissolved in 70 parts of water to form an alkaline solution (pH = 10.5), and 120 parts of diethylene glycol butyl ether acetate, 60 parts of hexaethyl phosphoramidite, and 150 parts of nano-montmorillonite were added in sequence. The mixture was stirred at high shear speed (1300 rpm) for 30 minutes and mixed until uniform to obtain a modified solution.

[0080] 60 parts of gold tailings were immersed in the modification solution and stirred continuously for 20 min. After being taken out, they were dried and solidified at 40 °C to obtain modified gold tailings.

[0081] (2) Small prefabricated components for highway engineering based on modified gold tailings, the raw materials include, by weight:

[0082] 60 parts of modified gold tailings, 6 parts of activator, 32 parts of active mineral admixture, 8 parts of epoxy resin, 2 parts of water reducer, 0.5 parts of expansion agent, 0.5 parts of air entraining agent, 0.3 parts of fiber, and 17 parts of water.

[0083] In the activator, the mass ratio of red mud, industrial by-product gypsum and carbide slag is 15:5:5;

[0084] In the active mineral admixture, the mass ratio of blast furnace slag powder, coal gangue powder, silica fume, steel slag powder, high-grade territorial sand, recycled aggregate powder and incineration fly ash is 45:15:1:5:5:8:12;

[0085] Among the fibers, the nanoscale fibers are graphene fibers, the millimeter-scale fibers are polypropylene fibers, and the mass ratio of the nanoscale fibers to the millimeter-scale fibers is 2:5.

[0086] (3) The preparation method of small prefabricated components for highway engineering based on modified gold tailings is as follows:

[0087] The activator and the active mineral admixture were mixed and then ball-milled to obtain a powder mixture; during the ball-milling process, the ball-to-material ratio was 5:1, the ball-milling time was 2 min, and the rotation speed was 400 r / min.

[0088] Add the modified gold tailings, powder mixture, expansion agent, air entraining agent and fiber into the concrete mixer in sequence according to the designed ratio, stir at a speed of 45 r / min for 10 minutes, and obtain a solid mixture after mixing evenly;

[0089] All the water, epoxy resin and water reducing agent were added, stirred at a speed of 45 r / min for 5 minutes, and after mixing evenly, a slurry for small prefabricated components for highway engineering based on modified gold tailings was obtained;

[0090] The small-scale prefabricated component slurry for highway engineering based on modified gold tailings is poured into a mold to obtain the small-scale prefabricated component for highway engineering based on modified gold tailings.

[0091] Example 3

[0092] (1) Preparation of modified gold tailings:

[0093] 30 parts of calcium nitrite were dissolved in 70 parts of water to form an alkaline solution (pH = 10.5), 20 parts of diethylene glycol butyl ether acetate, 20 parts of hexaethyl phosphoramidite, and 100 parts of nano-montmorillonite were added in sequence, and high-speed shear stirring (1300 rpm) was performed for 30 minutes to obtain a modified solution after mixing.

[0094] 58 parts of gold tailings were immersed in the modification solution and stirred continuously for 25 min. After being taken out, they were dried and solidified at 40 °C to obtain modified gold tailings.

[0095] (2) Small prefabricated components for highway engineering based on modified gold tailings, the raw materials include, by weight:

[0096] 58 parts of modified gold tailings, 8 parts of activator, 32 parts of active mineral admixture, 15 parts of epoxy resin, 1.5 parts of water reducer, 1 part of expansion agent, 1 part of air entraining agent, 0.5 parts of fiber, and 15 parts of water.

[0097] In the activator, the mass ratio of red mud, industrial by-product gypsum and carbide slag is 15:10:2;

[0098] In the active mineral admixture, the mass ratio of blast furnace slag powder, coal gangue powder, silica fume, steel slag powder, high-grade territorial sand, recycled aggregate powder and incineration fly ash is 55:20:3:10:8:10:10;

[0099] Among the fibers, the nano-scale fibers are carbon nanotube fibers, the millimeter-scale fibers are steel fibers, and the mass ratio of the nano-scale fibers to the millimeter-scale fibers is 1.5:7.

[0100] (3) The preparation method of small prefabricated components for highway engineering based on modified gold tailings is as follows:

[0101] The activator and the active mineral admixture were mixed and then ball-milled to obtain a powder mixture; during the ball-milling process, the ball-to-material ratio was 2:1, the ball-milling time was 3 min, and the rotation speed was 500 r / min.

[0102] Add the modified gold tailings, powder mixture, expansion agent, air entraining agent and fiber into the concrete mixer in sequence according to the designed ratio, stir at a speed of 45 r / min for 5 minutes, and obtain a solid mixture after mixing evenly;

[0103] All the water, epoxy resin and water reducing agent were added, stirred at a speed of 45 r / min for 8 minutes, and after mixing evenly, a slurry for small prefabricated components for highway engineering based on modified gold tailings was obtained;

[0104] The small-scale prefabricated component slurry for highway engineering based on modified gold tailings is poured into a mold to obtain the small-scale prefabricated component for highway engineering based on modified gold tailings.

[0105] Example 4

[0106] (1) Preparation of modified gold tailings:

[0107] 30 parts of calcium nitrite were dissolved in 70 parts of water to form an alkaline solution (pH = 10.5), 30 parts of diethylene glycol butyl ether acetate, 15 parts of hexaethyl phosphoramidite, and 75 parts of nano-montmorillonite were added in sequence, and high-speed shear stirring (1300 rpm) was performed for 30 minutes to obtain a modified solution after mixing.

[0108] 64 parts of gold tailings were immersed in the modification solution and stirred continuously for 30 min. After being taken out, they were dried and solidified at 50 °C to obtain modified gold tailings.

[0109] (2) Small prefabricated components for highway engineering based on modified gold tailings, the raw materials include, by weight:

[0110] 64 parts of modified gold tailings, 9 parts of activator, 32 parts of active mineral admixture, 10 parts of epoxy resin, 0.5 parts of water reducer, 1 part of expansion agent, 0.5 parts of air entraining agent, 0.1 parts of fiber, and 15 parts of water.

[0111] In the activator, the mass ratio of red mud, industrial by-product gypsum and carbide slag is 10:8:5;

[0112] In the active mineral admixture, the mass ratio of blast furnace slag powder, coal gangue powder, silica fume, steel slag powder, high-grade territorial sand, recycled aggregate powder and incineration fly ash is 40:15:2:5:8:5:12;

[0113] Among the fibers, the nanoscale fibers are graphene fibers, the millimeter-scale fibers are steel fibers, and the mass ratio of the nanoscale fibers to the millimeter-scale fibers is 1:6.

[0114] (3) The preparation method of small prefabricated components for highway engineering based on modified gold tailings is as follows:

[0115] The activator and the active mineral admixture were mixed and then ball-milled to obtain a powder mixture; during the ball-milling process, the ball-to-material ratio was 5:1, the ball-milling time was 2 min, and the rotation speed was 400 r / min.

[0116] Add the modified gold tailings, powder mixture, expansion agent, air entraining agent and fiber into the concrete mixer in sequence according to the designed proportion, stir at a speed of 45 r / min for 8 minutes, and obtain a solid mixture after mixing evenly;

[0117] All the water, epoxy resin and water reducing agent were added, stirred at a speed of 45 r / min for 8 minutes, and after mixing evenly, a slurry for small prefabricated components for highway engineering based on modified gold tailings was obtained;

[0118] The small-scale prefabricated component slurry for highway engineering based on modified gold tailings is poured into a mold to obtain the small-scale prefabricated component for highway engineering based on modified gold tailings.

[0119] Example 5

[0120] (1) Preparation of modified gold tailings:

[0121] 30 parts of calcium nitrite were dissolved in 70 parts of water to form an alkaline solution (pH = 10.5), 20 parts of diethylene glycol butyl ether acetate, 20 parts of hexaethyl phosphoramidite, and 80 parts of nano-montmorillonite were added in sequence, and high-speed shear stirring (1300 rpm) was performed for 30 minutes to obtain a modified solution after mixing.

[0122] 58 parts of gold tailings were immersed in the modification solution and stirred continuously for 25 min. After being taken out, they were dried and solidified at 45°C to obtain modified gold tailings.

[0123] (2) Small prefabricated components for highway engineering based on modified gold tailings, the raw materials include, by weight:

[0124] 58 parts of modified gold tailings, 5 parts of activator, 28 parts of active mineral admixture, 8 parts of epoxy resin, 1.5 parts of water reducer, 0.8 parts of expansion agent, 0.8 parts of air entraining agent, 0.2 parts of fiber, and 20 parts of water.

[0125] In the activator, the mass ratio of red mud, industrial by-product gypsum and carbide slag is 15:5:2;

[0126] In the active mineral admixture, the mass ratio of blast furnace slag powder, coal gangue powder, silica fume, steel slag powder, high-grade territorial sand, recycled aggregate powder and incineration fly ash is 52:18:3:5:6:8:14;

[0127] Among the fibers, the nano-scale fibers are carbon nanotube fibers, the millimeter-scale fibers are polyethylene fibers, and the mass ratio of the nano-scale fibers to the millimeter-scale fibers is 2:5.

[0128] (3) The preparation method of small prefabricated components for highway engineering based on modified gold tailings is as follows:

[0129] The activator and the active mineral admixture were mixed and then ball-milled to obtain a powder mixture; during the ball-milling process, the ball-to-material ratio was 4:1, the ball-milling time was 2 min, and the rotation speed was 500 r / min.

[0130] Add the modified gold tailings, powder mixture, expansion agent, air entraining agent and fiber into the concrete mixer in sequence according to the designed ratio, stir at a speed of 45 r / min for 10 minutes, and obtain a solid mixture after mixing evenly;

[0131] All the water, epoxy resin and water reducing agent were added, stirred at a speed of 45 r / min for 10 minutes, and after mixing evenly, a slurry for small prefabricated components for highway engineering based on modified gold tailings was obtained;

[0132] The small-scale prefabricated component slurry for highway engineering based on modified gold tailings is poured into a mold to obtain the small-scale prefabricated component for highway engineering based on modified gold tailings.

[0133] Comparative Example 1

[0134] The raw materials for small prefabricated components for highway engineering are C40 ordinary concrete, which contains 12 parts of P·O 425 cement, 6.8 parts of water, 35 parts of river sand, 18 parts of 5-10 mm limestone crushed stone, 28 parts of 10-20 mm limestone crushed stone, and 0.2 parts of water reducer. The raw materials are poured into a concrete mixer and stirred at 45 r / min for 10 minutes to obtain a slurry. The slurry is then poured into a mold to obtain small prefabricated components for highway engineering.

[0135] Comparative Example 2

[0136] The difference between this comparative example and Example 1 is that 26 parts of active mineral admixture and 5 parts of activator in the raw materials are replaced by 31 parts of ordinary Portland PO42.5 cement in equal parts. Other methods and steps are the same as those in Example 1 and are not repeated here.

[0137] Comparative Example 3

[0138] The difference between this comparative example and Example 1 is that the raw material gold tailings is not modified. Other methods and steps are the same as those in Example 1 and are not repeated here.

[0139] Comparative Example 4

[0140] The difference between this comparative example and Example 1 is that the raw material does not contain an air-entraining agent. Other methods and steps are the same as those in Example 1 and are not described here in detail.

[0141] Comparative Example 5

[0142] The difference between this comparative example and Example 1 is that the raw materials do not contain a swelling agent. Other methods and steps are the same as those in Example 1 and will not be repeated here.

[0143] Comparative Example 6

[0144] The difference between this comparative example and Example 1 is that the raw materials do not contain epoxy resin. Other methods and steps are the same as those in Example 1 and are not repeated here.

[0145] Comparative Example 7

[0146] The difference between this comparative example and Example 1 is that the raw material does not contain fiber. Other methods and steps are the same as those in Example 1 and are not repeated here.

[0147] Example 6

[0148] According to JTG 3420-2020 “Test Procedures for Cement and Cement Concrete for Highway Engineering”, the small prefabricated components for highway engineering obtained in Examples 1-5 and Comparative Examples 1-7 were subjected to 3d, 7d, and 28d compressive strength tests, shrinkage tests, and salt-freeze resistance tests. The results are shown in Table 2.

[0149] Table 2 Test results

[0150]

[0151] By comparing the effects of the examples and the comparative examples, we can see that comparative example 1 (C40 ordinary concrete) lacks the micro-aggregate filling effect of gold tailings and the pozzolanic reaction between gold tailings and active mineral admixtures, resulting in a high porosity of the cement matrix, insufficient C-S-H gel formation, and the lack of the pore buffering mechanism of the air-entraining agent, resulting in a high salt freeze loss. Comparative example 2 (active admixture replaced with ordinary cement) lacks the pozzolanic reaction, resulting in the enrichment of Ca(OH)2 in the hydration product and the reaction with Cl -The formation of expansive Friedel salts, combined with hydration thermal cracking caused by high cement dosage, exacerbates salt-freeze erosion and increases chemical shrinkage. In Comparative Example 3 (unmodified gold tailings), free water adsorbed by clay minerals on the gold tailings' surface leads to an increased water-cement ratio, weak interfacial bonding, and stress concentration. Furthermore, the unmodified tailings have high water absorption and interconnected pores, exacerbating freeze-thaw moisture migration and the swelling-shrinkage cycle. In Comparative Example 4 (no air-entraining agent), the lack of uniformly enclosed microbubbles prevents the release of frost heave pressure, accelerating salt solution penetration. In Comparative Example 5 (no expansive agent), concrete shrinkage cannot be compensated, leading to cracking. This further reduces the concrete's salt-freeze resistance and accelerates its failure. In Comparative Examples 6 (no epoxy resin) and 7 (no fiber), the microscopic voids cannot be filled, making them more susceptible to salt solution penetration. Furthermore, the concrete has low interfacial strength and insufficient shrinkage resistance. In summary, Examples 1 to 5 achieved compressive strength (≥40 MPa), salt freeze resistance (stripping amount <1500g / m 2 ) and volume stability, while the comparative ratio destroys the multi-scale (microscopic pores ~ mesoscopic interface ~ macroscopic structure) collaborative protection network due to the lack of a single component.

[0152] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A small prefabricated component for highway engineering based on modified gold tailings, characterized in that: The raw materials include by weight: 52-64 parts of modified gold tailings, 5-9 parts of activator, 26-32 parts of active mineral admixture, 8-15 parts of epoxy resin, 0.5-2 parts of water reducer, 0.5-1 parts of expansion agent, 0.5-1 parts of air entraining agent, 0.1-0.5 parts of fiber and 10-20 parts of water; The preparation method of the modified gold tailings comprises the following steps: Diethylene glycol butyl ether acetate, hexaethyl phosphoramidite and nano-montmorillonite are sequentially added to the calcium nitrite aqueous solution and mixed evenly to obtain a modified solution; The gold tailings are immersed in a modification liquid, stirred, taken out, dried and solidified to obtain modified gold tailings; The mass ratio of calcium nitrite, nano-montmorillonite, diethylene glycol butyl ether acetate and hexaethyl phosphoramidite is (1~3):(5~10):(2~4):(1~2).

2. The small prefabricated component for highway engineering based on modified gold tailings according to claim 1, characterized in that: The concentration of calcium nitrite aqueous solution is 28~40%; Soak the gold tailings in the modified solution for 20 to 30 minutes; The particle size of gold tailings is 75~600 μm.

3. The small prefabricated component for highway engineering based on modified gold tailings according to claim 1, characterized in that: The activator consists of red mud, industrial by-product gypsum and carbide slag, and the mass ratio of the red mud, industrial by-product gypsum and carbide slag is (10-15): (5-10): (2-5).

4. The small prefabricated component for highway engineering based on modified gold tailings according to claim 1, characterized in that: The active mineral admixture consists of blast furnace slag powder, coal gangue powder, silica fume, steel slag powder, high-grade terrestrial ore, recycled aggregate fine powder and incineration fly ash; the mass ratio of the blast furnace slag powder, coal gangue powder, silica fume, steel slag powder, high-grade terrestrial ore, recycled aggregate fine powder and incineration fly ash is (40~55):(15~20):(1~3):(5~10):(3~8):(5~10):(10~15).

5. The small prefabricated component for highway engineering based on modified gold tailings according to claim 1, characterized in that: The epoxy resin is a water-based epoxy resin with a solid content of 99% and an epoxy equivalent weight of 190-220 g / eq.

6. The small prefabricated component for highway engineering based on modified gold tailings according to claim 1, characterized in that: The water reducing agent is a polycarboxylic acid water reducing agent with a water reduction rate greater than 40%.

7. The small prefabricated component for highway engineering based on modified gold tailings according to claim 1, characterized in that: The expansion agent is a calcium aluminum sulfate expansion agent; The air entraining agent is rosin soap.

8. The small prefabricated component for highway engineering based on modified gold tailings according to claim 1, characterized in that: The fibers include nano-scale fibers and millimeter-scale fibers, and the mass ratio of the nano-scale fibers to the millimeter-scale fibers is (1-2): (5-7); The nanoscale fiber is one of carbon nanotube fiber and graphene fiber, and has a particle size of 10 to 30 nm; The millimeter-scale fiber is one of polyethylene fiber, polypropylene fiber, and steel fiber, and has a particle size of 2 to 4 mm.

9. The method for preparing a small prefabricated component for highway engineering based on modified gold tailings according to any one of claims 1 to 8, characterized in that: The steps include: (1) The activator and the active mineral admixture are mixed and then ball-milled to obtain a powder mixture; (2) uniformly mixing the modified gold tailings, powder mixture, expander, air entraining agent and fiber to obtain a solid mixture; (3) adding all the water, epoxy resin and water reducing agent to the solid mixture and mixing them evenly to obtain a slurry for small prefabricated components for highway engineering based on modified gold tailings; (4) Pour the slurry of small prefabricated components for highway engineering based on modified gold tailings into a mold to obtain small prefabricated components for highway engineering based on modified gold tailings.

10. The preparation method according to claim 9, characterized in that In step (1), during the ball milling process, the ball-to-material ratio is (2:1) to (5:1), the ball milling time is 2 to 3 minutes, and the rotation speed is 400 to 500 r / min.

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