Production process of asphalt concrete by using waste mineral aggregate to replace machine-made sand

Abstract

The application relates to the technical field of building material production, and discloses a production process of asphalt concrete by replacing machine-made sand with waste mine material, which comprises the following steps: screening the waste mine material to obtain fine aggregate with a particle size of 0.075mm-2.36mm; high-temperature calcining the screened waste mine material; performing surface acidification treatment on the high-temperature calcined waste mine material; and loading a nano catalyst on the surface acidification treated waste mine material. The surface activity and interface bonding performance of the waste mine material are improved through the steps of screening, high-temperature calcining, surface acidification treatment, nano catalyst loading and interface active agent treatment. The modified waste mine material is mixed with coarse aggregate, asphalt and functional reinforcing materials in proportion to prepare asphalt mixture, the asphalt mixture has excellent compressive strength, shearing strength and durability, and can be widely applied to ordinary highway, expressway and municipal road repair engineering.

Description

Technical Field

[0001] This invention relates to the field of building materials production technology, specifically to a process for producing asphalt concrete using waste mineral materials as a substitute for manufactured sand. Background Technology

[0002] With the acceleration of urbanization, the demand for high-quality building materials in road construction and building engineering is constantly increasing. Manufactured sand, as a major source of fine aggregate, is widely used in asphalt concrete and concrete engineering. Manufactured sand is typically prepared by crushing and screening hard rocks such as limestone. Due to its excellent particle shape, particle size distribution, and physical properties, it has long been favored in the engineering field. However, with the increasing scarcity of natural limestone resources, its mining and processing costs have continued to rise. This not only significantly increases project costs but also further exacerbates the over-reliance on natural resources and the damage to the ecological environment. Therefore, finding an economically feasible and environmentally friendly alternative to manufactured sand has become an important issue that the industry urgently needs to address.

[0003] Meanwhile, a large amount of waste mineral materials (such as waste rock) generated during mining and urban construction have not been fully utilized. Long-term accumulation not only occupies significant land resources but also poses serious environmental pollution risks, including heavy metal infiltration into water and soil and dust pollution. Due to their abundant reserves and low cost, waste mineral materials are considered a potential alternative to manufactured sand. However, because the surface of waste mineral materials is often covered with impurities, inactive oxides, and organic pollutants, their interfacial bonding with binders (such as asphalt or cement) is poor. Furthermore, the internal structure of the mineral material may contain absorbent pores or a loose structure, making it difficult to meet practical requirements for mechanical properties and durability when directly applied to engineering materials. Current technologies for utilizing waste mineral materials mainly focus on simple cleaning or crushing processes, failing to fundamentally address the problems of insufficient chemical activity and weak cross-sectional bonding.

[0004] Therefore, existing technologies have many shortcomings in treating waste minerals to replace manufactured sand. First, the lack of systematic surface treatment and modification processes makes it difficult to effectively remove impurities and inactive layers from the mineral surface, resulting in a lack of significant improvement in interfacial bonding performance. Second, there is limited application of deep processing technologies for waste minerals (such as high-temperature calcination and nano-modification), failing to fully utilize their potential active sites and limiting their value for resource utilization. Existing technologies focus more on the production and optimization of manufactured sand, rather than organically combining the treatment of mine waste with the development of manufactured sand alternatives. Efficient resource utilization technologies for waste minerals urgently need to be developed to reduce the production costs of engineering materials, solve the environmental problems of mine waste accumulation, and contribute to the sustainable development of the green building materials industry. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an asphalt concrete production process that uses waste mineral materials to replace manufactured sand. This solves the problem that existing technologies focus more on the production and optimization of manufactured sand, but fail to organically combine the treatment of mine waste with the development of alternative materials for manufactured sand.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a process for producing asphalt concrete using waste mineral materials as a substitute for manufactured sand, comprising the following steps: The waste mineral material is screened to obtain fine aggregate with a particle size of 0.075 mm to 2.36 mm; The screened waste ore is then calcined at high temperature. Surface acidification treatment is performed on waste ore after high-temperature calcination; Nanocatalysts are loaded onto waste mineral materials that have undergone surface acidification treatment; Introduce surfactants onto the surface of waste mineral materials; Asphalt mixtures are prepared by mixing waste minerals, coarse aggregates, asphalt, and functional reinforcing materials in a certain proportion, wherein the mass percentage of waste minerals is 50%–70%, the mass percentage of coarse aggregates is 20%–30%, the mass percentage of asphalt is 5%–8%, and the mass percentage of functional reinforcing materials is 0.5%–1.5%. The prepared asphalt mixture is used for road construction.

[0007] Furthermore, the main purpose of screening is to remove large particles and fine powder impurities, ensure that the waste mineral material has a uniform particle size, meet the requirements of fine aggregate, avoid the impact of excessively large or small particles on the flowability and skeleton stability of the mixture, and provide a suitable particle surface area for subsequent steps.

[0008] High-temperature calcination decomposes organic matter and adsorbs moisture on the surface of the ore, exposes the active sites of the ore, and enhances its surface chemical reactivity. In addition, the calcination process can also improve the hardness and wear resistance of waste ore, providing the aggregate with stronger load-bearing capacity and stability.

[0009] Acidification treatment further removes oxides and calcium compounds from the surface of the ore through chemical corrosion, while forming an active film layer on the surface, which enhances the specific surface area and polarity of the ore surface, providing a good substrate for the subsequent adhesion of nano-catalysts.

[0010] The loading of nanocatalysts further enhances the chemical reactivity and interfacial energy of waste mineral surfaces by depositing catalytically active materials (such as nano-TiO2 or CeO2) on the surface of the minerals, making them more likely to chemically combine with asphalt molecules and improve overall bonding performance.

[0011] Surfactants enhance the wettability and dispersibility between waste minerals and asphalt by adjusting the surface charge and hydrophilic / hydrophobicity of particles, thus preventing the aggregates from agglomerating in the mixture and improving the overall uniformity and stability.

[0012] Waste aggregates, acting as fine and coarse aggregates, together form the skeleton structure of the mixture. Coarse aggregates provide load-bearing and deformation resistance, while waste aggregates fill the gaps in the skeleton, ensuring the compactness of the mixture. Asphalt, acting as a binder, provides the flexibility and adhesion of the mixture, while functional reinforcing materials (such as nanocatalysts or modified polymers) further optimize the bonding performance between the aggregates and asphalt.

[0013] By using the mixture in road construction, the performance of waste mineral materials can be fully utilized, while ensuring that the road surface strength, durability and fatigue resistance meet the engineering requirements.

[0014] Preferably, the high-temperature calcination temperature of the waste ore is 600℃~800℃, the calcination time is 1.5 hours~2 hours, and the equipment for high-temperature calcination is a rotary kiln.

[0015] Furthermore, a calcination temperature within the range of 600℃ to 800℃ ensures the thorough removal of organic matter and moisture from the ore surface, while preventing excessively high temperatures from causing surface melting or performance degradation. A calcination time of 1.5 to 2 hours ensures sufficient exposure of active sites within the particles. The rotary kiln, as a calcination device, features uniform temperature distribution and high heat exchange efficiency, effectively improving calcination quality.

[0016] Preferably, the surface acidification treatment includes the following steps: Prepare a mixed acid solution, wherein the mixed acid solution is a 1:1 mixture of 5% to 10% phosphoric acid and dilute hydrochloric acid, and adjust the pH value to 4.5 to 6; The calcined waste ore is soaked in the mixed acid solution for 30 to 60 minutes. The soaked waste minerals are rinsed with deionized water and dried.

[0017] Furthermore, the mixed acid solution chemically corrodes the surface of the ore in an acidic environment, removing impurities and enhancing the surface activity of the ore. At the same time, it forms a suitable acidic film layer, providing a basis for surface modification in subsequent steps. The soaking time is controlled between 30 and 60 minutes to ensure that the acid solution reacts fully with the particle surface and avoids excessive corrosion of the particle surface due to excessive soaking time. Rinsing can effectively remove residual acid solution and avoid acid-base neutralization reactions in subsequent processes. Drying can further reduce the surface moisture content of the ore and improve its stability.

[0018] Preferably, the nanocatalyst is nano-titanium dioxide or nano-cerium oxide with a particle size of 10nm to 50nm, and the mass concentration of the nanocatalyst solution is 0.5% to 1.5%.

[0019] Furthermore, nanoparticles with a particle size of 10nm to 50nm have a high specific surface area and active sites, which is beneficial for the uniform distribution of the catalyst on the surface of the ore. A solution mass concentration of 0.5% to 1.5% can ensure that the catalyst concentration is moderate, avoiding agglomeration due to excessively high concentration or affecting the effect due to excessively low concentration.

[0020] Preferably, the loading of the nanocatalyst includes the following steps: The waste mineral material is placed in a vacuum coating device and the nano-catalyst solution is sprayed evenly. Dry the sprayed waste mineral material at a temperature of 100℃~120℃ for 1 hour~2 hours; The dried waste ore is then subjected to secondary calcination at a temperature of 400℃ to 600℃ for a duration of 0.5 to 1 hour.

[0021] Furthermore, vacuum coating equipment can enhance the adhesion between the catalyst and the ore surface, ensuring uniform coating. Low-temperature drying can prevent catalyst deactivation and promote uniform fixation of the catalyst on the ore surface. Secondary calcination helps to enhance the bonding strength between the catalyst and the ore surface, while activating the chemical properties of the catalyst.

[0022] Preferably, the surfactant is nonylphenol polyoxyethylene ether or sulfonate, and the mass concentration of the surfactant solution is 0.1% to 0.5%.

[0023] Furthermore, by adjusting the hydrophilicity and hydrophobicity of the mineral surface, the surfactant enhances the wettability and dispersibility of the mineral and asphalt, promoting their uniform bonding. A surfactant solution with a mass concentration of 0.1% to 0.5% ensures that the surfactant molecules are uniformly adsorbed on the mineral surface, while avoiding the deterioration of the mixture performance caused by excessive addition.

[0024] Preferably, the surfactant is introduced onto the surface of the waste mineral material by spraying, and then dried after being stirred evenly at room temperature.

[0025] Furthermore, introducing surfactants through spraying ensures uniform distribution of surfactants and avoids unevenness caused by local over-distribution; stirring at room temperature facilitates rapid adsorption of surfactants, while the drying step removes excess moisture from the surface, ensuring good dispersibility and interfacial properties of the mineral material in subsequent preparation.

[0026] Preferably, the functional enhancement material is cement, lime powder, or modified epoxy resin, wherein the amount of cement or lime powder added is 2% to 3%, and the amount of modified epoxy resin added is 0.5% to 1%.

[0027] Furthermore, functional reinforcing materials improve the tensile strength and fatigue resistance of asphalt mixtures by filling micropores in the mixture and enhancing the bond strength between particles; cement and lime powder have alkaline activity and can react chemically with silicates in the aggregate to improve interfacial strength; modified epoxy resin can further enhance the overall stability and durability of the mixture by forming a cross-linked network.

[0028] Preferably, the mixing temperature of the asphalt mixture is 160℃~180℃, and the mixing time is 90 seconds~120 seconds.

[0029] Furthermore, a mixing temperature of 160℃~180℃ can bring the asphalt to its optimal flow state, ensuring that it can evenly cover the surface of the aggregates and ore; a mixing time of 90 seconds~120 seconds can avoid asphalt aging due to excessive time, while ensuring that the components are fully mixed, thus improving the uniformity and stability of the mixture.

[0030] Preferably, when the asphalt mixture is used for road construction, the paving thickness is 5cm to 15cm, the initial compaction temperature is 90℃ to 110℃, and it is compacted 3 to 5 times with a steel wheel roller.

[0031] Furthermore, a paving thickness of 5cm to 15cm ensures the smoothness and load-bearing capacity of the road surface; controlling the initial compaction temperature at 90℃ to 110℃ allows the mixture to reach its optimal compaction state, preventing insufficient density due to excessively low temperature; compaction with a steel wheel roller for 3 to 5 passes effectively improves the density and shear strength of the mixture, ensuring that the road surface meets the usage requirements.

[0032] This invention provides a process for producing asphalt concrete using waste mineral materials as a substitute for manufactured sand. It offers the following advantages: 1. This invention employs a technical solution involving screening, high-temperature calcination, acid treatment, and loading with nano-catalysts onto waste mineral materials. Through deep modification, it significantly improves the surface activity and chemical bonding properties of the waste mineral materials, effectively replacing traditional manufactured sand in asphalt concrete. Compared to existing technologies that directly utilize waste mineral materials as fine aggregates, which suffer from insufficient surface activity and poor bonding properties, this invention solves the shortcomings of low resource utilization rates and inadequate road performance requirements associated with waste mineral materials.

[0033] 2. This invention employs a technical solution of introducing surfactants onto the surface of waste aggregates and loading functional reinforcing materials to improve the wettability and adhesion between waste aggregates and asphalt, achieving a significant improvement in the uniformity and fatigue resistance of asphalt mixtures. Compared to existing technologies that fail to adequately control the aggregate-asphalt interface, leading to insufficient pavement shear strength and durability, this invention solves the problem of pavement cracking and early damage caused by weak interfacial bonding.

[0034] 3. This invention employs a technical solution that uses waste mineral materials to replace manufactured sand. By optimizing the processing technology and proportioning design of waste mineral materials, it achieves the technical effects of reducing raw material costs and minimizing the environmental impact of mining. Compared to the resource consumption and high costs associated with relying on natural manufactured sand as fine aggregate in existing technologies, this invention solves the shortcomings of tight manufactured sand supply and significant environmental pressure.

[0035] 4. This invention employs technical solutions that optimize asphalt mixture mixing process parameters, control paving thickness, and design compaction processes. This ensures the uniformity and density of the asphalt mixture during construction, achieving the technical effects of improving pavement load-bearing capacity and extending service life. Compared to existing technologies where insufficient control of mixture proportions and construction parameters leads to poor pavement durability, this invention solves the problem of pavement prone to settlement, cracking, and other defects. Attached Figure Description

[0036] Figure 1 This is a flowchart of the steps of the present invention. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Please see the appendix Figure 1 : Example 1: Using waste mineral materials to replace manufactured sand in the preparation of asphalt mixtures for ordinary highway construction. Implementation Example Description Waste mineral screening and cleaning Waste minerals with a particle size of 0.075mm to 2.36mm were screened, washed, and dried for later use.

[0039] High-temperature calcination The material is calcined at 700°C for 1.8 hours in a rotary kiln to remove adsorbed moisture and organic matter from the surface of the ore.

[0040] Surface acidification treatment Prepare a mixed solution of 6% phosphoric acid and 6% dilute hydrochloric acid (1:1 ratio), adjust the pH value to 5.0, soak the mineral material for 40 minutes, rinse and dry.

[0041] Nanocatalyst loading A 1.0% concentration of nano-titanium dioxide solution (particle size 20nm) was uniformly sprayed, dried at 110℃ for 1.5 hours, and then calcined at 500℃ for 0.8 hours.

[0042] Surfactant treatment Spray with a 0.3% concentration of nonylphenol polyoxyethylene ether solution, stir evenly, and then dry.

[0043] Asphalt mixture preparation and construction mix proportions: 60% waste mineral aggregate, 25% coarse aggregate (granite), 7% asphalt, and 3% functional reinforcing material (lime powder).

[0044] Stir at 170℃ for 100 seconds, spread to a thickness of 10cm, initial compaction temperature of 100℃, and compact 4 times.

[0045] Comparative Example 1-1 (without surface acidification treatment) The process in this comparative example is completely identical to that in Example 1, except that the surface acidification step is removed. The waste ore after high-temperature calcination is directly used for subsequent catalyst loading and mixture preparation.

[0046] Comparative Examples 1-2 (without nanocatalysts) The process in this comparative example is basically the same as in Example 1, but the nanocatalyst loading step is omitted. The calcined ore is directly sprayed with surfactants after acid treatment.

[0047] Comparative Examples 1-3 (Low-Temperature Calcination Process) The comparative example differs in the calcination temperature; the high-temperature calcination temperature is adjusted to 500°C, and the time is shortened to 1 hour. The remaining steps are consistent with those in Example 1.

[0048] Summary of Implementation Examples Example 1, through a series of optimized steps including sieving, calcination, acid treatment, nanocatalyst loading, and surfactant treatment, significantly improved the activity of waste minerals and their interfacial bonding performance with asphalt. Compared to the comparative example, surface acidification, catalyst loading, and high-temperature calcination played a crucial role in improving the overall performance of asphalt mixtures, especially in ordinary highways, where a balance between performance and cost was effectively achieved.

[0049] Example 2: High-performance waste mineral asphalt mixture for highway pavement Implementation Example Description Waste mineral screening and high-temperature calcination The ore with a particle size of 0.075mm to 1.25mm was screened, washed, and then calcined at 750℃ for 2 hours.

[0050] Surface acidification treatment Prepare a mixed solution of 8% phosphoric acid and 8% dilute hydrochloric acid (1:1 ratio), adjust the pH value to 4.8, soak the mineral material for 50 minutes, then rinse and dry.

[0051] Nanocatalyst loading A 1.2% concentration of nano-cerium oxide solution (particle size 15nm) was uniformly sprayed, dried at 115℃ for 1 hour, and then calcined at 450℃ for 0.5 hours.

[0052] Functional enhancement materials added Add 0.8% modified epoxy resin emulsion.

[0053] Asphalt mixture preparation and construction mix proportions: waste mineral aggregate 55%, coarse aggregate (limestone) 30%, asphalt 7%, functional reinforcing material 0.8%.

[0054] Stir at 175℃ for 110 seconds, spread to a thickness of 8cm, initial compaction temperature of 105℃, and compact 5 times.

[0055] Comparative Example 2-1 (without secondary calcination) This comparative example is basically the same as Example 2, but the secondary calcination step after loading the nanocatalyst is omitted, and the mineral material after spraying the catalyst is directly used for the preparation of asphalt mixture.

[0056] Comparative Example 2-2 (without added functional enhancement materials) In this comparative example, no functional enhancement material (modified epoxy resin emulsion) was added during the process, and the remaining steps were the same as in Example 2.

[0057] Comparative Examples 2-3 (insufficient acidification treatment time) In this comparative example, the soaking time of the ore was shortened to 20 minutes during the acidification stage, while the remaining steps remained the same.

[0058] Summary of Implementation Examples Example 2 addresses the high strength, durability, and fatigue resistance requirements of highways by employing rigorous acid treatment, nano-cerium oxide loading, and modified epoxy resin reinforcement to ensure the high performance of the mixture. Comparative experiments show that secondary calcination and functional reinforcement materials play a crucial role in performance improvement, while shortening the acid treatment time may lead to a decrease in interfacial bonding ability.

[0059] Example 3: Economic waste mineral asphalt mixture for municipal road repair Implementation Example Description Waste mineral screening and cleaning Screen the mineral material with a particle size of 0.15mm to 2.36mm, wash it, and then dry it for later use.

[0060] High-temperature calcination Calcination at 650℃ for 1.5 hours partially improved the activity of the particles.

[0061] Acidification treatment Prepare a 5% phosphoric acid and 5% dilute hydrochloric acid (1:1 ratio) mixed solution, adjust the pH value to 5.5, soak the mineral material for 30 minutes, then rinse and dry.

[0062] Nanocatalyst loading A 0.8% concentration of nano-titanium dioxide solution was uniformly sprayed and dried at 100°C for 1 hour, omitting the secondary calcination step.

[0063] Asphalt mixture preparation and construction mix proportion: 65% waste mineral aggregate, 20% coarse aggregate (limestone), 6% asphalt, and 2% functional reinforcing material (cement).

[0064] Mix at 165℃ for 90 seconds, spread to a thickness of 6cm, initial compaction temperature of 95℃, and compact 3 times.

[0065] Comparative Example 3-1 (catalyst loading omitted) The process of this comparative example is basically the same as that of Example 3, but the nanocatalyst loading step is omitted.

[0066] Comparative Example 3-2 (Insufficient calcination temperature) In this comparative example, the calcination temperature was adjusted to 500℃ and the time was 1 hour, while the remaining steps were the same.

[0067] Summary of Implementation Examples Example 3, focusing on economic efficiency and addressing the performance requirements of municipal road repair, improved the resource utilization rate of waste minerals while controlling production costs through simplified process design and appropriate optimization. Comparative experimental results show that catalyst loading and appropriate calcination temperature play a crucial role in performance improvement, while low calcination temperature and lack of catalyst loading significantly affect pavement durability and uniformity.

[0068] Example 4: Optimized waste mineral asphalt concrete production process based on nanomaterials Detailed steps Collection and preliminary treatment of waste mineral materials Collect waste minerals from mining operations or mine waste and send them to a processing station.

[0069] The waste mineral material is screened using a vibrating screen to remove lumps and impurities with a particle size greater than 2.36 mm, while retaining fine aggregates with a particle size of 0.075 mm to 2.36 mm.

[0070] Composition analysis of waste minerals X-ray fluorescence spectrometry (XRF) was used to analyze the chemical composition of the sieved ore, including the content of major components such as silicon, calcium, and iron.

[0071] If on-site conditions are limited, wet leaching can be used to make a preliminary judgment on the main components of the ore to ensure that the ore composition is suitable.

[0072] Mixture design and auxiliary material adjustment Based on the composition analysis results of the mineral materials, adjust the addition ratio of cement or lime powder to make it account for 2% to 3% of the total mass of the mixture.

[0073] Nanomaterials (such as nano-silica with a particle size of 10nm to 50nm) are introduced as reinforcing agents to prepare a nanomaterial solution with a mass concentration of 1% for surface coating of waste minerals, thereby improving their surface activity and interfacial bonding performance.

[0074] Mixture ratio design: 55% waste minerals, 30% coarse aggregates, 6%–8% hot asphalt, 2%–3% cement or lime powder, and 0.5%–1.0% nanomaterials by mass.

[0075] Production of asphalt mixtures In the asphalt concrete mixing plant, the raw materials are added in the following order: waste minerals, coarse aggregates, nanomaterial solution, auxiliary materials (cement or lime powder), and hot asphalt.

[0076] Start the automatic control system, set the stirring temperature to 165℃~175℃, and the stirring time to 90 seconds~120 seconds to ensure that the materials are mixed evenly.

[0077] Construction and laying The mixture is transported to the construction site and paved with a paver to a thickness of 8cm to 12cm.

[0078] The initial compaction temperature is controlled between 95℃ and 110℃. A steel wheel roller is used for compaction, and four compaction passes are performed. The final compaction ensures that the road surface density meets the specifications.

[0079] Quality control and equipment inspection The mixing temperature and time are monitored in real time during the production process to ensure stable material performance.

[0080] Regularly check the operating status of screening machines, mixing equipment, and transportation equipment to avoid fluctuations in material properties due to equipment problems.

[0081] Technical advantages and features The introduction of nanomaterials: Nano-silica forms a highly active layer on the surface of waste mineral materials through surface coating, which significantly improves the interfacial bonding force between the mineral materials and asphalt, while enhancing the mechanical properties and durability of the mixture.

[0082] Material performance optimization: The introduction of nanomaterials makes the internal structure of the mixture more compact, effectively improving compressive strength, fatigue resistance and water damage resistance.

[0083] Synergistic effects of multiple modifications: The synergistic effect of nanomaterials and cement / lime powder not only strengthens the interaction between particles, but also further optimizes the stability of the mixture under high temperature and harsh environment.

[0084] Application scenarios for effect verification: Suitable for highways and heavy traffic sections, and projects with high requirements for mechanical performance and durability.

[0085] Expected performance improvement: Compared with traditional processes that do not introduce nanomaterials, compressive strength is increased by about 15% to 20%, fatigue life is extended by about 30% to 40%, and water stability coefficient is increased to 0.92 to 0.96.

[0086] Economic and environmental benefits: Replacing manufactured sand reduces material costs by about 20% to 30%, while achieving efficient resource utilization of waste minerals and alleviating the pressure of mine waste storage.

[0087] This embodiment introduces nanomaterials into the existing waste mineral utilization process. Through the dual effects of physical and chemical modification, it comprehensively improves the performance of asphalt mixtures, making it suitable for engineering scenarios with higher requirements for road performance. At the same time, it has significant economic and environmental value.

[0088] Comparative logic analysis Examples and Comparative Examples 1 Surface acidification and nano-catalyst loading are key processes for improving the interfacial bonding performance between waste mineral materials and asphalt. Failure to perform acidification or omission of catalyst loading will result in a significant decrease in bonding performance, making it difficult to meet the performance requirements of ordinary highways.

[0089] Examples and Comparative Examples 2 Highways require higher strength and durability; failure to undergo secondary calcination or omission of functional reinforcing materials will significantly weaken the fatigue performance and shear resistance of the mixture.

[0090] Examples and Comparative Examples 3 Municipal road repair emphasizes economy. The absence of catalysts or insufficient calcination temperature will lead to uneven quality of the mixture, which will not meet the durability requirements of municipal engineering. This shows that even in economical design, key processes cannot be omitted.

[0091] Through multi-dimensional comparison of the embodiments and comparative examples, the technical advantages and creativity of the present invention in the resource utilization of waste mineral materials are fully highlighted.

[0092] Experimental Design To comprehensively verify the effectiveness of this invention and its comparative advantages with comparative examples, the following test experiments were designed. The experiments focused on the road performance, mechanical properties, and economic efficiency of the mixture, with particular attention to compressive strength, fatigue resistance, shear strength, and pavement durability, while also analyzing the application scenarios. The following experiments consist of multiple test items, specifically designed as follows: Road performance testing Experimental Objective The study aims to verify the road performance (such as compressive strength, shear strength, and fatigue performance) of the asphalt mixture prepared by this invention in different application scenarios (ordinary roads, expressways, and municipal road repair), and to compare the performance differences between the examples and comparative examples.

[0093] Experimental methods Sample preparation: Standard Marshall samples were prepared for each group according to the formulations of Examples 1, 2, and 3. The sample dimensions were 101.6 mm in diameter and 63.5 mm in height.

[0094] The samples of the comparative examples (1-1, 1-2, 1-3; 2-1, 2-2, 2-3; 3-1, 3-2) were prepared according to the corresponding formulations and parameters, and were consistent with the samples of the examples.

[0095] Each group of samples shall contain no fewer than 6 pieces.

[0096] Test content and methods: Compressive strength test: The Marshall stability tester was used to test the maximum compressive load at a loading rate of 50 mm / min, and the compressive strength was calculated.

[0097] Shear strength test: The shear strength of the mixture was measured using a direct shear test apparatus at a shear rate of 1 mm / min.

[0098] Fatigue performance test: Using a dynamic fatigue testing machine, at a frequency of 10 Hz and in constant strain mode, the number of failures of the specimen under cyclic loading was recorded.

[0099] Data Analysis The numerical differences in compressive strength, shear strength, and fatigue life between the comparative examples and the control examples were compared to analyze the effects of waste ore surface treatment, catalyst loading, and high-temperature calcination on performance.

[0100] Expected results: The specimens in the examples (especially Example 2) exhibited higher compressive and shear strengths, and their fatigue life was significantly better than that of the comparative specimens.

[0101] Durability test Experimental Objective The durability of the mixture of the present invention was verified by simulating long-term use environment, with a focus on analyzing the contribution of high-temperature calcination and surface treatment to durability.

[0102] Experimental methods Sample preparation: Prepare samples for Examples 1, 2, 3 and Comparative Examples (1-1, 2-1, 3-1), with no less than 4 samples in each group.

[0103] Sample dimensions: diameter 101.6 mm, height 63.5 mm.

[0104] Test content and methods: Freeze-thaw cycle test: The sample was frozen at -18℃ for 24 hours, then transferred to a 20℃ water bath to thaw for 24 hours. After 10 freeze-thaw cycles, the residual compressive strength was measured.

[0105] High temperature stability test: A rutting test was conducted on asphalt mixtures at a high temperature of 60℃, and the rutting depth was recorded.

[0106] Water stability test: The Marshall test involves immersing the sample in water for 48 hours to test its compressive strength.

[0107] Data Analysis The performance differences between the comparative examples and the control examples in freeze-thaw, high-temperature and water stability tests were compared to analyze the effects of waste mineral activation treatment and catalyst loading on durability improvement.

[0108] Expected results: Examples 1, 2, and 3 showed better performance in terms of freeze-thaw loss, rut depth, and water stability, especially Example 2, which showed better high-temperature stability.

[0109] Economic Analysis Experiment Experimental Objective This paper analyzes the actual effect of the present invention in reducing costs by replacing manufactured sand with waste mineral materials.

[0110] Experimental methods Cost calculation: Asphalt mixtures of Examples 1, 2, and 3 were prepared, and the combined cost of waste minerals, functional reinforcement materials, asphalt, and processing energy consumption was calculated.

[0111] Calculate the combined cost of untreated waste minerals and unloaded catalysts in comparative examples (1-1, 2-1, 3-1).

[0112] The cost is compared with the production cost of traditional manufactured sand asphalt mixture.

[0113] Data Analysis: By comparing the cost proportions of each group, the economic advantages of this invention in the resource utilization of waste minerals are analyzed.

[0114] Expected results: Examples 1 and 3 show higher economic efficiency, especially Example 3, which reduces costs by 30% to 40% compared to the manufactured sand solution.

[0115] Application scenario adaptability experiment Experimental Objective The applicability of this invention is verified by considering the actual requirements for the repair of ordinary highways, expressways, and municipal roads.

[0116] Experimental methods Sample preparation: Examples 1 and comparative examples (1-2, 1-3) were prepared for ordinary highways.

[0117] For the highway preparation Example 2 and Comparative Examples (2-1, 2-2) samples.

[0118] Samples for municipal repair were prepared in Example 3 and Comparative Examples (3-1, 3-2).

[0119] Test content and methods: Applications on ordinary highways: Test compressive strength and fatigue performance to determine the performance of Example 1 on a road surface with medium traffic volume.

[0120] Highway applications: Shear strength and rut depth were tested to analyze the suitability of Example 2 in heavy traffic.

[0121] Municipal road repair: The compressive strength and water stability were tested, and the suitability of Example 3 for light-load transportation and low-cost requirements was analyzed.

[0122] Data Analysis The performance differences between the comparative examples and the control examples in different application scenarios were compared to analyze the effect of process optimization on improving application adaptability.

[0123] Expected results: The embodiments demonstrate better overall adaptability, especially Embodiment 2, which meets the high-intensity requirements of highways, while Embodiment 3 highlights cost advantages.

[0124] Summarize The above experimental design, fully integrated with the embodiments and comparative examples, comprehensively verified the technical advantages of the present invention through tests on road performance, durability, economy, and application scenario adaptability. Each experiment adopted standardized procedures and comparative analysis, clearly highlighting the creativity and practical application value of the present invention in the resource utilization of waste minerals, performance improvement of mixtures, and cost control.

[0125] Experiment 1: Road Performance Test Experimental instructions The objective of this experiment is to verify the contribution of key technologies in the process of this invention (such as high-temperature calcination, surface acidification treatment, and nano-catalyst loading) to improving the performance of asphalt mixtures by testing their compressive strength, shear strength, and fatigue properties in the examples and comparative examples. The experiments employed the standard Marshall test method and the direct shear test method, combined with dynamic fatigue performance testing, to comprehensively evaluate the road performance of each mixture.

[0126] Experimental steps Sample preparation: Example Samples: Samples were prepared according to the process formulas and parameters of Examples 1, 2 and 3, with no less than 6 samples in each group.

[0127] Comparative sample: Samples were prepared according to the formulation and parameters of comparative examples (1-1, 1-2, 1-3; 2-1, 2-2, 2-3; 3-1, 3-2), with the same number and size as the sample samples in the examples.

[0128] Sample dimensions: diameter 101.6 mm, height 63.5 mm, meeting the Marshall test standard.

[0129] Compressive strength test: A Marshall stability tester was used to apply a load at the center of the specimen at a rate of 50 mm / min, and the maximum load (kN) at failure was recorded.

[0130] Formula for calculating compressive strength (MPa): Where F is the maximum load and r is the sample radius.

[0131] Shear strength test: Shear strength was tested using a direct shear tester at a shear rate of 1 mm / min. The shear force (kN) at failure was recorded. The formula for calculating shear strength (MPa) is as follows: Where F is the shear force and A is the shear surface area.

[0132] Fatigue performance test: A dynamic fatigue testing machine was used, with a loading frequency of 10 Hz and a constant strain mode. Cyclic loading was applied, and the number of loading cycles (Nf) before specimen failure was recorded.

[0133] Data recording and analysis: The compressive strength, shear strength, and fatigue life of each group of samples were recorded and summarized in a table.

[0134] Experimental data The following are the test data for Experiment 1 (Table name: Road Performance Test Results). Example 1 5.2 1.15 18000 Comparative Example 1-1 4.3 0.98 10500 Comparative Examples 1-2 4.7 1.02 12500 Comparative Examples 1-3 4.5 1.00 11000 Example 2 6.8 1.40 26000 Comparative Example 2-1 5.5 1.20 18500 Comparative Example 2-2 6.0 1.25 21000 Comparative Examples 2-3 5.7 1.22 19000 Example 3 4.8 1.05 14000 Comparative Example 3-1 4.1 0.92 9000 Comparative Example 3-2 4.3 0.95 9500

[0135] Summary and Mechanism Analysis Based on Experiment 1 This experiment, through road performance tests on the examples and comparative examples, verified the effectiveness of the key processes of this invention (such as high-temperature calcination, surface acidification treatment, and nano-catalyst loading) in improving the performance of the mixture. The samples from the examples showed significant advantages in compressive strength, shear strength, and fatigue life. In particular, the combination of high-temperature calcination and nano-cerium oxide loading in Example 2 increased the compressive strength and fatigue life by approximately 24% and 40%, respectively, fully meeting the high strength and high durability requirements of highways.

[0136] Compared to Comparative Example 1-1 (without acid treatment), the compressive strength and fatigue life of Example 1 were significantly improved. This was mainly due to the acidic active film layer formed on the surface of the mineral by the acid treatment, which enhanced the interfacial bonding force between the mineral and the asphalt. At the same time, the loading of the nano-catalyst further improved the surface activity and chemical bonding ability of the mineral in the example. In contrast, the samples of Comparative Example 1-2 had slightly lower performance due to the lack of catalyst treatment, especially the fatigue life, which was only about 70% of that of the example.

[0137] The test results of Example 3 demonstrate the applicability of the economical mixture in municipal road repair. Although slightly inferior to Example 1 in compressive strength and fatigue life, it still meets the basic performance requirements of municipal engineering and significantly reduces production costs by moderately simplifying the process and reducing the treatment intensity. Comparative Examples 3-1 (without catalyst) and 3-2 (insufficient calcination temperature) both showed significant performance degradation, especially in the fatigue life test, where the number of loading cycles decreased by approximately 35%–40%, reflecting the crucial role of catalyst loading and high-temperature calcination in the activation treatment of the aggregate.

[0138] Based on mechanistic analysis, high-temperature calcination enhances the chemical reactivity of the mineral aggregate by removing adsorbates from its surface and exposing active sites. The synergistic effect of acidification and nanocatalysts further improves the bonding force between the mineral aggregate and asphalt molecules, thereby significantly improving the mechanical properties and fatigue life of the mixture. This experiment fully verifies the technical advantages of this invention in the resource utilization of waste mineral aggregates, especially demonstrating excellent road performance and economic benefits in different scenarios such as ordinary highways, expressways, and municipal roads.

[0139] Experiment 2: Durability Test Experimental instructions The experimental objective is to verify the durability performance of the asphalt mixture prepared by this invention by simulating long-term use environments (such as freeze-thaw cycles, high-temperature conditions, and water immersion), especially its resistance to freeze-thaw damage, high-temperature stability, and water stability. By comparing the examples with comparative examples, the contributions of high-temperature calcination, surface acidification treatment, and nanocatalyst loading in the process of this invention to durability are further revealed.

[0140] Experimental steps Sample preparation: Marshall specimens with a diameter of 101.6 mm and a height of 63.5 mm were prepared according to the process parameters of Examples 1, 2, 3 and Comparative Examples (1-1, 1-2, 1-3; 2-1, 2-2, 2-3; 3-1, 3-2), with no less than 6 specimens in each group.

[0141] Freeze-thaw cycle test: The sample was frozen at -18°C for 24 hours, and then transferred to a 20°C water bath to thaw for 24 hours.

[0142] After 10 freeze-thaw cycles, Marshall stability tests were performed, and the ratio of residual compressive strength (TSR) before and after the freeze-thaw cycles was calculated using the following formula: High temperature stability test: The samples were subjected to rutting tests in a 60℃ constant temperature chamber. A loading device was used to simulate vehicle load, and the rutting depth (mm) was recorded.

[0143] Water stability test: According to the Marshall test method for immersion, the sample is immersed in a water bath at 60°C for 48 hours, and then its compressive strength is tested to calculate the water stability coefficient (immersion compressive strength / initial compressive strength).

[0144] Experimental data The following are the test data for Experiment 2 (Table name: Durability Test Results). Example 1 88.4 2.5 0.93 Comparative Example 1-1 71.2 4.1 0.80 Comparative Examples 1-2 78.5 3.7 0.85 Comparative Examples 1-3 74.3 3.9 0.82 Example 2 92.6 2.1 0.96 Comparative Example 2-1 83.7 3.2 0.88 Comparative Example 2-2 86.1 2.8 0.90 Comparative Examples 2-3 84.5 3.0 0.89 Example 3 82.3 3.5 0.88 Comparative Example 3-1 67.4 4.6 0.75 Comparative Example 3-2 70.8 4.3 0.78

[0145] Summary and Mechanism Analysis Based on Experiment 2 Durability test results showed that the example specimens significantly outperformed the comparative specimens in terms of freeze-thaw cycles, rutting depth, and water stability coefficient. Example 1 exhibited excellent freeze-thaw compressive strength in ordinary highway applications, with a freeze-thaw residual compressive strength ratio as high as 88.4%, significantly higher than the 71.2% of Comparative Example 1-1. This is attributed to the improvement of the surface chemical properties of the aggregates through acid treatment and nano-catalyst loading, which resulted in a more stable interfacial bond between the aggregates and asphalt, thereby reducing damage caused by moisture intrusion during freeze-thaw cycles. In contrast, Comparative Example 1-1, without acid treatment, still had a loose impurity layer on the aggregate surface, which was insufficient to effectively prevent moisture intrusion, leading to a decline in freeze-thaw performance.

[0146] Example 2 demonstrated particularly outstanding high-temperature stability, with a rutting depth of only 2.1 mm, significantly lower than the 3.2 mm of Comparative Example 2-1. This difference is primarily attributed to the synergistic treatment of high-temperature calcination and nano-cerium oxide in Example 2, which significantly improved the high-temperature deformation resistance and interfacial bonding of the waste mineral material. Mechanistically, high-temperature calcination exposes active sites on the mineral material surface, while nano-cerium oxide further enhances the physicochemical bonding strength between the mineral material and asphalt molecules, thereby improving the mixture's resistance to rutting under high-temperature conditions. In contrast, Comparative Example 2-1, by omitting the secondary calcination step, resulted in insufficient bonding between the mineral material and asphalt, leading to an increased rutting depth.

[0147] In the scenario of municipal road repair, the water stability coefficient of Example 3 reached 0.88, which meets the basic requirements of light traffic. However, the water stability coefficient of Comparative Example 3-1 was only 0.75 due to the absence of a catalyst, which showed obvious performance deficiencies. This indicates that even in economical designs, the role of nano-catalysts cannot be ignored. Nano-catalysts not only improve the surface chemical properties of the minerals, but also form a stable chemical film at the interface, effectively preventing the penetration and diffusion of water. In contrast, the minerals in the comparative example without catalysts are prone to reduced binding performance due to water infiltration.

[0148] In summary, this experiment fully verifies the contributions of high-temperature calcination, acid treatment, and nanocatalyst loading to the improved durability of this invention. Mechanistically, the waste mineral material, through multiple treatment processes, not only removes the surface impurity layer but also significantly enhances the chemical bonding force between the mineral material and the asphalt interface, thus exhibiting excellent durability under harsh conditions such as freeze-thaw cycles, high temperatures, and water immersion. This advantage makes the mixture of this invention highly applicable and economical in applications such as the repair of ordinary roads, highways, and municipal roads.

[0149] Experiment 3: Application Scenario Adaptability Test Experimental instructions The objective of this experiment is to verify the performance adaptability of the invention in different scenarios, specifically addressing the practical application needs of repairing ordinary highways, expressways, and municipal roads. The experiment involves comprehensive testing of compressive strength, shear strength, rut depth, and water stability coefficient, comparing the performance differences between the embodiment and the corresponding embodiment to verify the applicability of the invention in practical engineering applications.

[0150] Experimental steps Sample preparation Example Samples: Samples were prepared according to the formulations and parameters of Examples 1, 2 and 3, with no fewer than 6 samples in each group.

[0151] Comparative sample: Samples were prepared according to the formulations and parameters of Comparative Examples 1-1, 1-2, 1-3; 2-1, 2-2, 2-3; 3-1, 3-2. The number and size of the samples were the same as those in the examples.

[0152] Sample dimensions: diameter 101.6 mm, height 63.5 mm.

[0153] Ordinary highway compatibility test Compressive strength test: The compressive strength test was conducted using a Marshall stability tester at a loading rate of 50 mm / min. The maximum load at failure was recorded, and the compressive strength was calculated.

[0154] Shear strength test: The shear strength test was carried out using a direct shear apparatus at a shear rate of 1 mm / min. The shear failure load was recorded and the shear strength was calculated.

[0155] Highway compatibility test Rutting depth test: Simulated rutting test was conducted in a 60℃ high-temperature rutting instrument, and the rutting depth (mm) formed under vehicle load was recorded.

[0156] Fatigue performance testing: A dynamic fatigue testing machine was used with a loading frequency of 10Hz, and the number of cyclic loading (Nf) before the specimen failed was recorded.

[0157] Municipal road repair compatibility test Water stability test: Following the Marshall immersion test method, the sample was immersed in a 60°C water bath for 48 hours, and the compressive strength was tested. The water stability coefficient was then calculated.

[0158] Compressive strength test: Same as the test method for ordinary highways.

[0159] Experimental data The following is the test data for Experiment 3 (Table name: Application Scenario Adaptability Test Results).

[0160] Summary and Mechanism Analysis Based on Experiment 3 Experimental results show that the mixture of the present invention exhibits excellent adaptability in three typical application scenarios: ordinary highways, expressways and municipal road repair. In particular, it is significantly better than the corresponding ratio in terms of compressive strength, shear strength and rutting depth. This performance advantage fully reflects the interface bonding enhancement effect achieved by the present invention through waste mineral surface treatment and nano-catalyst loading.

[0161] In ordinary highway scenarios, the compressive strength and shear strength of Example 1 reached 5.3 MPa and 1.16 MPa, respectively, which were about 20% and 22% higher than those of Comparative Example 1-1. This is because the present invention uses high-temperature calcination and acid treatment to remove impurities and organic matter adsorbed on the surface of the aggregate, making the surface of the aggregate cleaner. At the same time, the acidic active film layer enhances the interfacial bonding force with asphalt. In contrast, Comparative Example 1-1 did not undergo acid treatment, and impurities remained on the surface of the aggregate, making it difficult to form a stable interfacial bond, resulting in poor mechanical properties.

[0162] In the highway scenario, the rut depth of Example 2 was only 2.3 mm, and the fatigue life reached 25,000 cycles, which was far superior to the 3.1 mm and 18,000 cycles of Comparative Example 2-1. This indicates that the synergistic effect of high-temperature calcination and nano-cerium oxide loading significantly improved the high-temperature stability and fatigue resistance of the ore. Mechanistically, high-temperature calcination exposes the active sites on the surface of the ore, and the reinforcing film formed by nano-cerium oxide at the interface further improves the deformation resistance of the mixture. Comparative Example 2-1 did not undergo secondary calcination, so the active sites on the surface of the ore were insufficient and the interfacial bonding was weak. Therefore, it showed obvious performance degradation under high-temperature conditions.

[0163] In the scenario of municipal road repair, the water stability coefficient of Example 3 reached 0.89, which was significantly better than that of Comparative Example 3-1 (0.77). The introduction of nano-catalyst formed a chemically stable protective layer on the surface of the mineral, effectively preventing the intrusion of water. In contrast, Comparative Example 3-1, which did not have a catalyst loaded, lacked a chemical protective layer on the surface of the mineral, and its performance rapidly declined under water immersion. This result fully demonstrates that even in economical designs, catalyst loading still plays an important role in improving water resistance and interfacial bonding ability.

[0164] In summary, this invention achieves resource utilization and high-performance modification of waste mineral materials through three core technologies: high-temperature calcination, acidification treatment, and nanocatalyst loading. It is applicable to various engineering scenarios such as the repair of ordinary roads, expressways, and municipal roads. These technological optimizations not only improve the mechanical properties and durability of the mixture, but also significantly enhance its adaptability to complex working conditions, thus having broad engineering application prospects and economic value.

[0165] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for producing asphalt concrete using waste mineral materials as a substitute for manufactured sand, characterized in that, Includes the following steps: The waste mineral material is screened to obtain fine aggregate with a particle size of 0.075 mm to 2.36 mm; The screened waste ore is then calcined at high temperature. The waste ore after high-temperature calcination is subjected to surface acidification treatment. The surface acidification treatment includes the following steps: preparing a mixed acid solution, wherein the mixed acid solution is a mixture of 5% to 10% phosphoric acid and dilute hydrochloric acid in a 1:1 ratio, and adjusting the pH value to 4.5 to 6; immersing the calcined waste ore in the mixed acid solution for 30 to 60 minutes; rinsing the soaked waste ore with deionized water and drying it. A nanocatalyst is loaded onto waste mineral material that has undergone surface acidification treatment. The nanocatalyst is nano-titanium dioxide or nano-cerium oxide with a particle size of 10nm to 50nm, and the mass concentration of the nanocatalyst solution is 0.5% to 1.5%. The loading of the nanocatalyst includes the following steps: placing the waste mineral material in a vacuum coating equipment and uniformly spraying the nanocatalyst solution. The sprayed waste mineral material is dried at a temperature of 100℃~120℃ for 1 hour~2 hours; the dried waste mineral material is then calcined a second time at a temperature of 400℃~600℃ for 0.5 hours~1 hour. A surfactant is introduced onto the surface of the waste mineral material. The surfactant is nonylphenol polyoxyethylene ether or sulfonate, and the mass concentration of the surfactant solution is 0.1% to 0.5%. The surfactant is introduced onto the surface of the waste mineral material by spraying and then dried after being stirred evenly at room temperature. Asphalt mixtures are prepared by mixing waste minerals, coarse aggregates, asphalt, and functional reinforcing materials in a specific ratio, wherein the mass percentage of waste minerals is 50%–70%, the mass percentage of coarse aggregates is 20%–30%, the mass percentage of asphalt is 5%–8%, and the mass percentage of functional reinforcing materials is 0.5%–1.5%. The prepared asphalt mixture is used for road construction.

2. The asphalt concrete production process using waste mineral materials to replace manufactured sand according to claim 1, characterized in that, The waste ore is calcined at a temperature of 600℃ to 800℃ for 1.5 to 2 hours, and the equipment used for high-temperature calcination is a rotary kiln.

3. The asphalt concrete production process using waste mineral materials to replace manufactured sand according to claim 1, characterized in that, The functional enhancement material is cement, lime powder, or modified epoxy resin, wherein the amount of cement or lime powder added is 2% to 3%, and the amount of modified epoxy resin added is 0.5% to 1%.

4. The asphalt concrete production process using waste mineral materials to replace manufactured sand according to claim 1, characterized in that, The mixing temperature of the asphalt mixture is 160℃~180℃, and the mixing time is 90 seconds~120 seconds.

5. The asphalt concrete production process using waste mineral materials to replace manufactured sand according to claim 1, characterized in that, When the asphalt mixture is used for road construction, the paving thickness is 5cm to 15cm, the initial compaction temperature is 90℃ to 110℃, and it is compacted 3 to 5 times with a steel wheel roller.

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