Solid-waste-based artificial aggregate for ice melting and skid resistance of pavement in winter and preparation method of solid-waste-based artificial aggregate

Abstract

The invention discloses a solid-waste-based artificial aggregate for ice melting and skid resistance of a pavement in winter and a preparation method of the solid-waste-based artificial aggregate. The solid waste-based artificial aggregate adopts a multi-layer structure and comprises an inner core, a middle layer and an outer layer according to the weight part ratio of (50-70): (70-120): (1-2), wherein the middle layer comprises 1-3 parts of a foaming agent, 15-25 parts of fire coal fly ash, 10-20 parts of calcium sulfate waste residues, 5-10 parts of superfine slag powder, 20-30 parts of rock salt and 20-30 parts of slag cement. The preparation method comprises the following steps: screening steel slag to form a tip icebreaking inner core; mixing a middle-layer ice melting material, and coating the surface of the inner core with the mixed middle-layer ice melting material to reduce the freezing point; and the outer layer obstructs moisture and inhibits icing through a hydrophobic material. The steel slag and other solid wastes are converted into the multifunctional aggregate, the multifunctional aggregate has the ice breaking, ice melting and hydrophobic characteristics, and the ice melting skid resistance and safety of the road surface in winter can be remarkably improved. The process is simple and recoverable, solid waste accumulation and environmental pollution are obviously reduced, the ice and snow removal cost is reduced, and both environmental protection and economic benefits are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of road maintenance materials, and particularly relates to a solid waste-based artificial aggregate for winter road ice melting and anti-skid, and a preparation method thereof. Background Art

[0002] Snow and ice on roads in winter are important factors affecting traffic smoothness and safety. Snow and ice can cause a sharp drop in the friction of the road surface, making the driving stability of vehicles worse. It is extremely easy to have traffic accidents such as skidding and rollover, seriously threatening people's lives and property safety. At the same time, it also hinders the transportation of materials and the travel of people, having an adverse impact on social and economic activities. Therefore, timely and effectively removing snow and ice on roads is of great significance for ensuring road traffic safety and maintaining normal social operation.

[0003] Currently, common road snow and ice removal methods mainly include mechanical snow removal and snow melting salt snow removal. Mechanical snow removal relies on specialized snow removal equipment, such as snow removal vehicles, snow plows, etc. However, when the road surface is frozen, the friction is reduced, and the tires of snow removal vehicles are prone to skidding, making it difficult to drive stably and operate effectively, and the snow removal efficiency drops significantly. Snow melting salt snow removal is to spread snow melting salt on the road surface to lower the melting point of ice and snow and make it melt. However, the chemical components in snow melting salt will cause serious damage to the environment, such as polluting the soil and affecting plant growth; polluting surface water and groundwater and endangering the ecological balance. In addition, snow melting salt will also have an erosive effect on the metal and concrete structures in infrastructure such as roads and bridges, shortening their service life and increasing maintenance costs.

[0004] Neither mechanical snow removal nor traditional snow melting salt can effectively solve the anti-skid problem after the road surface is frozen. When a vehicle travels on an icy road surface, the friction between the tire and the road surface is extremely small, the braking distance increases significantly, and it is extremely easy to have traffic accidents such as vehicle skidding and out of control, seriously threatening people's lives and property safety.

[0005] In winter road maintenance, anti-skid particles, as key materials to ensure driving safety, have always received extensive attention. Although traditional anti-skid particles have a certain effect on road anti-skid, there are many limitations. It usually uses natural mineral materials such as quartz sand and emery, with high acquisition costs and ecological damage, and the problem of resource scarcity is aggravated. Structurally, it is relatively simple, mostly in a single particle form, with a lack of functional diversity, limited applicable scenarios, and poor anti-skid performance in low-temperature environments. In terms of performance, it cannot actively melt ice in the early stage of icing, the anti-skid ability decreases as the ice layer thickens, and it is easily affected by environmental factors such as humidity and snow accumulation. In addition, traditional anti-skid particles are difficult to recycle and reuse, and are abandoned after use, which not only wastes resources but may also pollute the environment, and will threaten the ecological system when washed into the natural environment by rainwater.

[0006] Therefore, it is urgent to develop an efficient, environmentally friendly, economical and good anti-slip winter road ice-melting material and method.

[0007] The treatment of industrial waste has always been a difficult problem that needs to be solved urgently. A large amount of coal combustion fly ash and calcium sulfate waste residue are generated during the production of rock salt. If these waste residues are discharged randomly, they will not only occupy a large amount of land resources, but also cause serious pollution to the surrounding soil, water body and atmospheric environment. At the same time, there are potential safety hazards in the large accumulation of waste residues, such as the collapse of waste residue piles. Applying these waste residues to the preparation of artificial aggregates can not only reduce the environmental pressure of waste residues, but also realize the secondary utilization of resources, which conforms to the concept of sustainable development. Summary of the Invention

[0008] The technical problem to be solved by the present invention is: aiming at the defects and deficiencies in the existing winter road snow and ice melting and anti-slip technologies, to provide a solid waste-based artificial aggregate for winter road ice melting and anti-slip and its preparation method, by recycling and treating industrial waste such as steel slag, coal combustion fly ash, and calcium sulfate waste residue, and converting these waste residues into components of artificial aggregates.

[0009] The technical solutions adopted by the present invention to solve the technical problems are as follows: A solid waste-based artificial aggregate for winter road ice melting and anti-slip, adopting a multi-layer composite structure, including a core, an intermediate layer and an outer layer. By weight: Core: 50-70 parts, with a particle size of 2-6 mm, which is steel slag with a rough surface and irregular shape; Intermediate layer: 70-120 parts, a slow-release composite layer composed of the following components: 1-3 parts of hydrogen peroxide foaming agent, 15-25 parts of coal combustion fly ash, 10-20 parts of calcium sulfate waste residue, 5-10 parts of slag micro-powder, 20-30 parts of rock salt with a NaCl content ≥ 95%, 20-30 parts of slag cement; Outer layer: 1-2 parts of an organosilicon resin hydrophobic layer with a thickness of 0.1-0.3 mm.

[0010] The coal combustion fly ash conforms to the Class F or Class C standard in GB / T 1596-2017: SiO2 + Al2O3+ Fe2O3 ≥ 70% (Class F) or ≥ 50% (Class C), and the unburned carbon content ≤ 5%; the calcium sulfate waste residue has a CaSO4 content ≥ 80% (calculated as dihydrate or hemihydrate calcium sulfate), an impurity content ≤ 10%, and a crushing particle size ≤ 0.15 mm.

[0011] The slag powder mentioned above meets the following requirements: specific surface area ≥ 450 m² / kg, SiO2 + Al2O3 ≥ 65%, metal oxide impurities ≤ 3%, and particle size distribution is 1 - 45 μm; the slag cement complies with GB / T 18046 - 2017, slag content ≥ 70%, specific surface area ≥ 400 m² / kg.

[0012] The thickness of the intermediate layer is 0.5 - 1.5 mm, and the porosity is 20% - 35%. The intermediate layer is formed by the following process: (1) Curing reaction is carried out for 2 - 4 hours under the conditions of temperature 40 - 60°C and relative humidity 60% - 80%; (2) The cured intermediate layer aggregate is transferred to a microwave reactor and subjected to microwave activation treatment for 5 - 10 minutes at a microwave frequency of 2.4 - 2.5 GHz and a power of 500 - 800 W.

[0013] The processing method of the outer layer is as follows: A hydrophobic material of silicone resin with a concentration of 5% - 10% is evenly sprayed through a spray gun at a pressure of 0.3 - 0.5 MPa, a spraying distance of 15 - 20 cm, and a hydrophobic surface contact angle of ≥ 150° to form an outer hydrophobic layer with a thickness of 0.1 - 0.3 mm.

[0014] The preparation method of the solid waste - based artificial aggregate includes the following steps: A. Inner core pretreatment: (1) Select irregular steel slag with a size of 2 - 6 mm by vibrating screening; (2) Remove surface oxides by pickling; (3) Dry at 80 - 100°C until the moisture content < 0.5%; B. Intermediate layer construction: (1) Dry - mix foaming agent, coal - fired fly ash, calcium sulfate waste residue, slag powder, rock salt, slag cement, etc., and then add water to make a mixed slurry with a solid content of 60% - 70%; (2) After wrapping the steel slag inner core with the mixed slurry, cure for 2 - 4 hours under the conditions of temperature 40 - 60°C and humidity 60% - 80%; (3) Transfer the cured intermediate layer aggregate to a microwave reactor and carry out microwave activation treatment for 5 - 10 minutes at a microwave frequency of 2.4 - 2.5 GHz and a power of 500 - 800 W; C. Outer layer modification: Spray a hydrophobic solution of silicone resin with a concentration of 5% - 10% on the surface of the constructed intermediate layer aggregate at a pressure of 0.3 - 0.5 Mpa and a distance of 15 - 20 cm to form a hydrophobic layer with a thickness of 0.1 - 0.3 mm, and dry at room temperature.

[0015] The conditions for the microwave activation treatment are as follows: microwave frequency 2.4 - 2.5 GHz, power 500 - 800 W, activation treatment time 5 - 10 minutes, and the material temperature is controlled at 50 - 70°C.

[0016] The calcium sulfate waste residue mentioned above is derived from the waste of rock salt production. The wet residue is collected by centrifugal separation or plate and frame filtration, and obtained by drying the wet residue at 100 - 150°C and then pulverizing it.

[0017] The coal - fired fly ash mentioned above is the fly ash collected from the flue gas of the coal - fired boiler during the rock salt production process after dust removal.

[0018] The solid - waste - based artificial aggregate is used for the ice - melting and anti - skid paving layer of winter roads, bridges or airport runways. Its ice - melting component is rock salt, which is slowly released to the road surface through the pores of the intermediate layer, and the release period matches the snowfall frequency.

[0019] In the present invention, the steel slag is selected by combining a vibrating screen and manual sorting to meet the requirements of particle size and geometric characteristics; the coal - fired fly ash and calcium sulfate waste residue are selected from the waste generated during the rock salt production in Yexian County, Pingdingshan.

[0020] The coal - fired fly ash preferably meets GB / T 1596 - 2017 (Fly ash used in cement and concrete), Class F or Class C, SiO2 + Al2O3 + Fe2O3 ≥ 70% (Class F) or ≥ 50% (Class C); the unburned carbon content ≤ 5%. During the rock salt production process, the fly ash is collected from the flue gas of the coal - fired boiler by an electrostatic precipitator or a bag filter, dried and stored in a closed bin.

[0021] The calcium sulfate waste residue preferably has a CaSO4 (dihydrate or hemihydrate calcium sulfate) content ≥ 80%; other impurities (such as NaCl, CaCO3) ≤ 10%. The wet residue is collected by centrifugal separation or plate and frame filtration, dried at 100 - 150°C and then pulverized to a particle size ≤ 0.15 mm for standby.

[0022] The slag powder preferably has a specific surface area ≥ 450 m² / kg, SiO2 + Al2O3 ≥ 65%, and metal oxide impurities (Fe2O3, MgO) ≤ 3%. It is further processed to a finer particle size by an ultrafine grinder, and the particle size distribution (1 - 45 μm) is controlled by air - flow classification screening for standby.

[0023] The rock salt mentioned above is sodium chloride (NaCl) - based rock salt produced in Yexian County, Pingdingshan, and its rock salt component is mainly NaCl (NaCl ≥ 95%).

[0024] The slag cement described above is preferably selected to comply with GB / T 18046-2017 (ground granulated blast-furnace slag powder), with a slag content of ≥70%; the specific surface area is ≥400 m² / kg, ground to the target fineness by a ball mill, and stored in a moisture-proof container for standby.

[0025] The core of the solid waste-based artificial aggregate described above: The main function of steel slag is to mechanically break the ice surface by virtue of its own hardness and shape when the wheel rolls over the ice surface, creating conditions for subsequent ice melting and anti-skid.

[0026] The middle layer of the solid waste-based artificial aggregate described above: Its main function is to adsorb moisture. When it comes into contact with the ice surface and meets water, deicing components such as rock salt gradually dissolve and are released, achieving the effect of ice melting.

[0027] The function of the foaming agent is to form foaming pores in the middle layer, increasing the porosity of the material. On the one hand, it helps to adsorb moisture and promotes the dissolution and release of deicing components; on the other hand, the porous structure can reduce the overall weight and make the aggregate more evenly distributed when spreading.

[0028] The coal combustion fly ash, as a waste in the production process of rock salt, has certain activity and pozzolanic effect. It can not only fill the material gaps and improve the compactness of the middle layer, but also react with calcium hydroxide in the slag cement to form cementitious substances (such as C-S-H gel), significantly enhancing the bonding and durability of the middle layer; its porous structure can adsorb deicing components (rock salt solution) and promote the slow release of deicing agents.

[0029] The calcium sulfate waste residue, as a waste in the production process of rock salt, can react with the component C3A in the slag cement to form ettringite (AFt), improving the setting time and strength development of the middle layer. In addition, its own structural characteristics also contribute to enhancing the storage and release capacity of deicing components.

[0030] The slag powder has a small particle size and strong cementitious effect, which can tightly bond other materials together to form a stable structure. At the same time, after contacting water, the cementitious characteristics of the slag powder can promote the uniform dispersion and slow release of deicing components, prolonging the duration of the ice melting effect.

[0031] The rock salt, as the main deicing component, dissolves when it meets water, reducing the melting point of ice and achieving the ice melting effect.

[0032] The slag cement hydrates to form C-S-H gel, which serves as the main cementitious phase of the middle layer, providing basic cementitious properties, bonding other materials into a whole, ensuring the strength and stability of the middle layer, and enabling it to function under various environmental conditions.

[0033] The outer layer of the solid waste-based artificial aggregate: It can effectively reduce the ability of water to freeze on the surface of the aggregate, keep the surface of the aggregate dry and rough in a humid environment, enhance the friction with the ice surface, and further improve the anti-slip effect.

[0034] The main innovations of the present invention are as follows: A. Innovation in raw material selection: The steel slag is selected as the core after screening. It has appropriate particle sizes and irregular rough geometric features, and can effectively transfer pressure under the action of vehicle tire pressure to achieve mechanical crushing of the ice layer, creating conditions for subsequent ice melting and anti-slip. The intermediate layer is composed of foaming pores generated by a foaming agent, coal fly ash, calcium sulfate waste residue, slag micro-powder, rock salt, and slag cement, and each component acts synergistically. The foaming pores increase the pore structure of the intermediate layer, which helps the adsorption and release of ice-melting components; the addition of industrial waste residues such as coal fly ash and calcium sulfate waste residue not only realizes the resource utilization of waste, but also cooperates with other components to enhance the ice melting and bonding effects; the gelling effect of slag micro-powder makes the intermediate layer structure more stable; rock salt, as the key component for ice melting, uses the principle of colligative properties of dilute solutions to lower the melting point of ice after dissolving in water to achieve the ice melting effect; slag cement provides basic gelling properties to bond other materials into a whole, ensuring the strength and stability of the intermediate layer so that it can play a role under various environmental conditions. The outer layer is made of an organic hydrophobic material, and its special molecular structure gives it a low molecular surface energy and a large water contact angle. When water comes into contact with the hydrophobic outer layer, water droplets are formed under the action of surface tension, making it difficult to spread and freeze on the surface of the aggregate, thereby reducing the ability of water to freeze on the surface of the aggregate, extending the service life of the aggregate, and ensuring the persistence of the ice melting and anti-slip effects.

[0035] B. Innovation in preparation process: In order to further improve the ice-melting and anti-skid performance, durability, environmental protection and economic performance of artificial aggregate on winter roads, the present invention adopts a specific preparation process. During the preparation process, the composition ratio and process parameters of each layer are strictly controlled. For example, when preparing the middle layer, the temperature is controlled at 40-60°C, the humidity is 60%-80%, and the curing reaction time is 2-4 hours. The cured middle layer aggregate is placed in a microwave reactor for microwave-assisted activation and treated for 5-10 minutes at a frequency of 2.45 GHz and a power of 500-800 W. Microwave radiation can excite the vibration of polar molecules (such as calcium sulfate and slag powder) inside the material, promote the uniform distribution of the pore structure and the reorganization of the crystal phase, and further improve the porosity of the middle layer and the slow release efficiency of the ice-melting component. At the same time, microwave treatment can shorten the curing time, enhance the interface bonding strength between the middle layer and the inner core, and ultimately ensure that the thickness of the middle layer is uniform and between 0.5 and 1.5 mm, which can not only ensure the effective adsorption and release of the ice-melting components, but also does not affect the stability of the overall structure; when preparing the outer layer, the hydrophobic material is prepared into a 5% to 10% solution, and is evenly sprayed through a spray gun at a pressure of 0.3 to 0.5 MPa and a distance of 15 to 20 cm to form a hydrophobic layer of 0.1 to 0.3 mm.

[0036] C. Innovation in application: In terms of the use effect, the aggregate is evenly spread on the road surface. In the early stage of ice formation, the snow-melting salt component inside the artificial aggregate releases the ice-melting component when it meets water, lowering the melting point of ice so that it dissolves and is discharged from the road surface; in the middle stage of ice surface, the wheel rolling causes the tip of the particle to break, and the interlocking effect of irregular particles increases the friction between the wheel and the road surface; in the late stage of ice surface, the spread aggregate forms dense protrusions, providing a fulcrum for the wheel to ensure the safety of vehicle traffic. In addition, after the winter road ice melting and anti-skid operation is completed, special recycling equipment (such as a sweeper with screening function) is used to collect the artificial aggregate remaining on the road surface. The recycled artificial aggregate is transported to the designated recycling and processing site, and the recycled artificial aggregate is screened to remove impurities (such as soil, stones, etc.) mixed in it. Then, according to the loss of artificial aggregate, an appropriate amount of new raw materials (such as steel slag, related materials of the middle layer and the outer layer) are added, and reprocessed according to the above preparation process to make new artificial aggregate for the next winter road ice melting and anti-skid operation.

[0037] The innovative principles of the present invention are as follows: 1. Principle of using steel slag mechanical crushing to prevent skidding: The steel slag core is the core part of the artificial aggregate. During the driving process of the wheel, it is subjected to the pressure of the tire. Due to its irregular shape, rough surface and multi-angle, when it contacts the ice surface, stress concentration is generated under the action of pressure, causing the ice surface to be locally subjected to a large impact force, thereby breaking the ice surface and destroying the ice layer structure. At the same time, the artificial aggregate spread on the ice surface forms dense protrusions, which provide additional points of force for the wheel, change the contact state between the wheel and the ice surface, increase friction, and ensure the safe driving of the vehicle.

[0038] 2. The principle of using the middle layer material to melt ice: When the ice-melting components such as rock salt in the middle layer come into contact with water, according to the colligative principle of dilute solutions, the melting point of ice will be lowered. The water around the ice begins to melt at a lower temperature, and the formed water flow discharges the ice from the road surface, achieving the ice-melting effect. At the same time, the porous structure of materials such as coal fly ash and calcium sulfate waste residue and the gelling effect of slag micropowder help to absorb moisture and promote the dissolution and release of ice-melting components.

[0039] 3. Utilize the hydrophobic principle of the outermost layer of material: The outermost layer of hydrophobic material forms a low surface energy film on the surface of the artificial aggregate, which increases the contact angle of water on the aggregate surface and makes it difficult to adhere and spread. When the moisture in the environment contacts the hydrophobic outer layer, it will form water droplets and roll down, thereby reducing the possibility of water freezing on the aggregate surface, keeping the aggregate surface dry and rough, and enhancing the friction with the ice surface.

[0040] Compared with the prior art, the present invention has the following positive and beneficial effects: 1. More efficient ice melting and anti-skid. The artificial aggregate of the present invention can play a good ice melting role under different temperatures and ice thickness conditions. Whether in the low temperature environment in the early stage of ice formation or in the later stage when the ice surface is thicker, it can effectively reduce the thickness of the ice layer, improve the road traffic capacity, and reduce traffic congestion and accidents caused by snow and ice. At the same time, through the crushing and squeezing effect of the particles and the dense protrusions formed on the ice surface, the artificial aggregate is provided with reliable anti-skid performance under different ice conditions, which significantly improves driving safety and reduces the risk of vehicles slipping on icy roads.

[0041] 2. Outstanding environmental benefits. Using industrial wastes such as steel slag, coal fly ash, and calcium sulfate waste residue as the main raw materials, the resource utilization of wastes is realized, and the pollution of wastes to the environment is reduced. At the same time, the corrosion of soil, plants, and road facilities by traditional snow-melting salt is avoided, and the ecological environment is protected.

[0042] 3. Good economic benefits. The use of a large amount of industrial waste reduces the cost of raw materials. The recyclable and reprocessable characteristics of artificial aggregates further reduce the long-term use cost, with a high cost-effectiveness ratio, providing an economically feasible solution for road ice melting and anti-skid projects.

[0043] The solid waste-based artificial aggregate of the present invention adopts a multi-layer structure synergistic effect to make its performance stable and durable. The hydrophobic outer layer effectively reduces the ability of water to freeze on the surface of the aggregate, and even in a continuous low temperature and humid environment, the performance of the aggregate can be kept stable to prevent its premature failure. The ice-melting components of the middle layer are slowly released to ensure the continuity of the ice-melting effect.

[0044] The solid waste-based artificial aggregate of the present invention performs well at different temperatures and ice thicknesses. In the early stage of ice formation, the internal snow-melting salt components such as rock salt dissolve in water and melt the ice according to the colligative principle of the solution; in the middle stage of ice formation, the wheel rolling breaks the tip of the particle, and the interlocking effect of irregular particles greatly increases the friction; in the late stage of ice formation, the dense protrusions formed by the aggregate provide a fulcrum for the wheel, ensuring the safe passage of the vehicle, greatly improving driving safety.

[0045] The present invention utilizes industrial wastes such as steel slag, coal-fired fly ash, and calcium sulfate waste residue as the main raw materials, thus realizing large-scale resource utilization of wastes. Taking a medium-sized city as an example, if the artificial aggregate of the present invention is used for road de-icing and anti-skid every winter, thousands of tons of wastes such as steel slag can be consumed, significantly reducing the pollution of wastes to the environment. Moreover, the use of traditional snow-melting salt is avoided, the ecological environment is effectively protected, the damage to soil, plants and road facilities is reduced, and it is helpful to maintain ecological balance and long-term stability of roads.

[0046] The present invention uses a large amount of industrial waste, which is widely available and low-cost. Compared with the mineral resources that traditional snow-melting salt relies on, the cost of purchasing raw materials is greatly reduced. In addition, artificial aggregates are recyclable and reprocessable. After the winter road ice-melting and anti-skid operation is completed, the remaining artificial aggregates are collected by special recycling equipment. After screening and supplementing with some new raw materials, they can be reprocessed into new artificial aggregates for the next year. This feature further reduces the long-term use cost and reduces resource waste. Calculated based on long-term use cycles, and taking into account the raw material costs and recycling and reuse factors, the artificial aggregates of the present invention provide an economically feasible solution for road ice-melting and anti-skid projects with a high cost-effectiveness ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the structure of the solid waste-based artificial aggregate in the present invention; Figure 2 This is a diagram showing the working mechanism of the solid waste-based artificial aggregate in three stages of the present invention. DETAILED DESCRIPTION

[0048] Example: A solid waste-based artificial aggregate for ice melting and anti-skid on winter roads, comprising a core, an intermediate layer and an outer layer. By weight: Core: 50 - 70 parts, with a particle size of 2 - 6 mm, which is steel slag with a rough surface and irregular shape; Intermediate layer: 70 - 120 parts, a slow-release composite layer composed of the following components: 1 - 3 parts of hydrogen peroxide foaming agent, 15 - 25 parts of coal combustion fly ash, 10 - 20 parts of calcium sulfate waste residue, 5 - 10 parts of slag micro-powder, 20 - 30 parts of rock salt with NaCl content ≥ 95%, 20 - 30 parts of slag cement; Outer layer: 1 - 2 parts of an organosilicon resin hydrophobic layer with a thickness of 0.1 - 0.3 mm.

[0049] The coal combustion fly ash meets the Class F or Class C standard in GB / T 1596 - 2017: SiO2 + Al2O3 + Fe2O3 ≥ 70% (Class F) or ≥ 50% (Class C), and the unburned carbon content ≤ 5%; the calcium sulfate waste residue has a CaSO4 content ≥ 80% (calculated as dihydrate or hemihydrate calcium sulfate), an impurity content ≤ 10%, and a pulverized particle size ≤ 0.15 mm.

[0050] The slag micro-powder meets the requirements: specific surface area ≥ 450 m² / kg, SiO2 + Al2O3 ≥ 65%, metal oxide impurities ≤ 3%, and the particle size distribution is 1 - 45 μm; the slag cement meets GB / T 18046 - 2017, with a slag content ≥ 70% and a specific surface area ≥ 400 m² / kg.

[0051] The thickness of the intermediate layer is 0.5 - 1.5 mm, and the porosity is 20% - 35%. It is formed by the following process: (1) Curing reaction for 2 - 4 hours under the conditions of temperature 40 - 60 °C and relative humidity 60% - 80%; (2) The cured intermediate layer aggregate is transferred to a microwave reactor and microwave-activated for 5 - 10 minutes at a microwave frequency of 2.4 - 2.5 GHz and a power of 500 - 800 W.

[0052] The processing method of the outer layer is as follows: The organosilicon resin hydrophobic material with a concentration of 5% - 10% is evenly sprayed through a spray gun at a pressure of 0.3 - 0.5 MPa, a spraying distance of 15 - 20 cm, and a hydrophobic surface contact angle ≥ 150° to form an outer layer hydrophobic layer with a thickness of 0.1 - 0.3 mm.

[0053] The preparation method of the above-mentioned solid waste-based artificial aggregate includes the following steps: A. Core pretreatment: (1)Select irregular steel slag with a size of 2 - 6 mm for vibration screening; (2)Remove surface oxides by pickling; (3)Dry at 80 - 100 °C until the moisture content is < 0.5%; B. Intermediate layer construction: (1)Dry - mix foaming agent, coal - fired fly ash, calcium sulfate waste residue, slag powder, rock salt, slag cement, etc., and then add water to make a mixed slurry with a solid content of 60% - 70%; (2)After wrapping the steel slag core with the mixed slurry, cure it for 2 - 4 hours under the conditions of a temperature of 40 - 60 °C and a humidity of 60% - 80%; (3)Transfer the cured intermediate - layer aggregate to a microwave reactor, and perform microwave activation treatment for 5 - 10 minutes at a microwave frequency of 2.4 - 2.5 GHz and a power of 500 - 800 W; C. Outer - layer modification: Spray a hydrophobic solution of silicone resin with a concentration of 5% - 10% on the surface of the aggregate of the constructed intermediate layer at a pressure of 0.3 - 0.5 Mpa and a distance of 15 - 20 cm to form a hydrophobic layer with a thickness of 0.1 - 0.3 mm, and air - dry at room temperature.

[0054] The conditions for microwave activation treatment are: microwave frequency 2.4 - 2.5 GHz, power 500 - 800 W, activation treatment time 5 - 10 minutes, and the material temperature is controlled at 50 - 70 °C.

[0055] The calcium sulfate waste residue is from the waste of rock - salt production. After centrifugal separation or plate - and - frame filtration to collect the wet slag, the wet slag is dried at 100 - 150 °C and then pulverized.

[0056] The coal - fired fly ash is the fly ash collected from the flue gas of the coal - fired boiler during the rock - salt production process.

[0057] The solid - waste - based artificial aggregate is used for ice - melting and anti - skidding on winter roads, bridges or airport runways. Its ice - melting component is rock salt, which is slowly released to the road surface through the pores of the intermediate layer, and the release period matches the snow - falling frequency.

[0058] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent transformations made on the basis of the technical solutions of this application fall within the protection scope of the present invention.

[0059] Example 1: A solid - waste - based artificial aggregate for ice - melting and anti - skidding on winter road surfaces given in this example, in parts by weight, the solid - waste - based artificial aggregate adopts a three - layer composite structure, including an inner core, an intermediate layer, and an outer layer, with a weight - part ratio of 60:95:1.5.

[0060] Specifically, it includes the following components: 60 parts of steel slag core; the intermediate layer material includes: 2 parts of hydrogen peroxide, 20 parts of coal combustion fly ash, 15 parts of calcium sulfate waste residue, 8 parts of slag powder, 25 parts of rock salt, 25 parts of slag cement; 1.5 parts of outer hydrophobic layer material.

[0061] The preparation method of the solid waste-based artificial aggregate in this embodiment includes the following steps: Step 1: By combining a vibrating screen and manual sorting, select 60 parts of steel slag with irregular shape and rough surface and particle size of 2 - 6 mm, and wash and dry the steel slag to remove impurities and moisture on the surface. Step 2: Weigh 2 parts of hydrogen peroxide, 20 parts of coal combustion fly ash, 15 parts of calcium sulfate waste residue, 8 parts of slag powder, 25 parts of rock salt, 25 parts of slag cement, and mix them evenly to obtain the intermediate layer raw material. Step 3: Mix the steel slag core with the intermediate layer raw material, and place it in an environment with a temperature of 50 °C and a humidity of 70% for a curing reaction for 3 hours to ensure that the thickness of the intermediate layer is uniform finally, and form steel slag particles coated with the intermediate layer. Step 4: Place the steel slag particles coated with the intermediate layer in a microwave reactor and process them at a power of 600 W for 8 minutes. Step 5: Prepare 1.5 parts of silicone resin hydrophobic material into a hydrophobic solution with a concentration of 8%, and pour it into a spray gun for standby. Step 6: Use the spray gun to spray on the surface of the steel slag particles coated with the intermediate layer at a pressure of 0.4 MPa and a distance of 18 cm to form a hydrophobic layer. Step 7: After the hydrophobic layer is sprayed, air-dry the artificial aggregate at room temperature to obtain the final uniform solid waste-based artificial aggregate.

[0062] For the solid waste-based artificial aggregate for winter road ice melting and anti-skidding prepared according to the above steps, measure the basic physical performance indexes of the artificial aggregate, and the specific index parameters are shown in Table 1, Table 2 and Table 3. Example

[0063] A solid waste-based artificial aggregate for winter road ice melting and anti-skidding given in this embodiment, in parts by weight, the solid waste-based artificial aggregate adopts a three-layer structure, including a core, an intermediate layer, and an outer layer, and the ratio by weight is 55:81.5:1.

[0064] Specifically, it includes the following components: 55 parts of steel slag core; the intermediate layer material includes: 1.5 parts of hydrogen peroxide, 18 parts of coal combustion fly ash, 12 parts of calcium sulfate waste residue, 6 parts of slag powder, 22 parts of rock salt, 22 parts of slag cement; 1 part of outer hydrophobic layer material.

[0065] The preparation process of the solid waste-based artificial aggregate in this embodiment is basically the same as that in Embodiment 1, and the same parts will not be repeated. The only difference is that it is prepared according to the formula of this embodiment.

[0066] For the solid waste-based artificial aggregate used for ice melting and anti-skid on winter roads prepared according to the above steps, measure the basic physical performance indexes of the artificial aggregate, and the specific index parameters are shown in Table 1, Table 2 and Table 3. Embodiment

[0067] A solid waste-based artificial aggregate for ice melting and anti-skid on winter roads given in this embodiment, in parts by weight, the solid waste-based artificial aggregate adopts a three-layer structure, including an inner core, an intermediate layer and an outer layer, with a weight ratio of 70:118:2.

[0068] Specifically, it includes the following components: 70 parts of steel slag inner core; the intermediate layer material includes: 3 parts of hydrogen peroxide, 25 parts of coal combustion fly ash, 20 parts of calcium sulfate waste residue, 10 parts of slag micro-powder, 30 parts of rock salt, 30 parts of slag cement; 2 parts of hydrophobic layer material.

[0069] The preparation process of the solid waste-based artificial aggregate in this embodiment is basically the same as that in Embodiment 1, and the same parts will not be repeated. The only difference is that it is prepared according to the formula of this embodiment.

[0070] For the solid waste-based artificial aggregate used for ice melting and anti-skid on winter roads prepared according to the above steps, measure the basic physical performance indexes of the artificial aggregate, and the specific index parameters are shown in Table 1, Table 2 and Table 3.

[0071] A solid waste-based artificial aggregate for ice melting and anti-skid on winter roads given in this comparative example, in parts by weight, the solid waste-based artificial aggregate adopts a three-layer structure, including an inner core, an intermediate layer and an outer layer, with a weight ratio of 60:93:1.5.

[0072] Specifically, it includes the following components: 60 parts of steel slag inner core; the intermediate layer material includes: 20 parts of coal combustion fly ash, 15 parts of calcium sulfate waste residue, 8 parts of slag micro-powder, 25 parts of rock salt, 25 parts of slag cement; 1.5 parts of hydrophobic layer material.

[0073] The preparation process of the solid waste-based artificial aggregate in this comparative example is basically the same as that in Embodiment 1, and the same parts will not be repeated. The only difference is that hydrogen peroxide is not added.

[0074] For the solid waste-based artificial aggregate used for ice melting and anti-skid on winter roads prepared according to the above steps, measure the basic physical performance indexes of the artificial aggregate, and the specific index parameters are shown in Table 1, Table 2 and Table 3.

[0075] A kind of solid waste-based artificial aggregate for ice melting and anti-skid on winter roads given in this comparative example, in parts by weight, the solid waste-based artificial aggregate adopts a multi-layer structure, including an inner core, an intermediate layer, and an outer layer, with a weight ratio of 55:81.5:0. Specifically, it includes the following components: 55 parts of steel slag inner core; 1.5 parts of hydrogen peroxide, 18 parts of coal fly ash, 12 parts of calcium sulfate waste residue, 6 parts of slag powder, 22 parts of rock salt, and 22 parts of slag cement.

[0076] The preparation process of the solid waste-based artificial aggregate in this comparative example is basically the same as that of Example 1, and the same parts will not be repeated. The only difference is that the hydrophobic material layer is not sprayed.

[0077] For the solid waste-based artificial aggregate for ice melting and anti-skid on winter roads prepared according to the above steps, measure the basic physical performance indicators of the artificial aggregate. For specific indicator parameters, refer to Table 1, Table 2, and Table 3.

[0078] A kind of solid waste-based artificial aggregate for ice melting and anti-skid on winter roads given in this comparative example, in parts by weight, the solid waste-based artificial aggregate adopts a multi-layer structure, including an inner core, an intermediate layer, and an outer layer, with a weight ratio of 70 parts: 118 parts: 2 parts. Specifically, it includes the following components: 70 parts of natural sand and gravel inner core; 3 parts of hydrogen peroxide, 25 parts of coal fly ash, 20 parts of calcium sulfate waste residue, 10 parts of slag powder, 30 parts of rock salt, 30 parts of slag cement; and 2 parts of hydrophobic layer material.

[0079] The preparation process of the solid waste-based artificial aggregate in this comparative example is basically the same as that of Example 1, and the same parts will not be repeated. The only difference is that natural sand and gravel are used to replace steel slag.

[0080] For the solid waste-based artificial aggregate for ice melting and anti-skid on winter roads prepared according to the above steps, measure the basic physical performance indicators of the artificial aggregate. For specific indicator parameters, refer to Table 1, Table 2, and Table 3.

[0081] Table 1 Basic physical performance indicators of artificial aggregates in each example and comparative example

[0082] Table 2 Performance changes of artificial aggregates under different storage times

[0083] Table 3 Performance changes after pressure accelerated aging test

[0084] 1. Performance advantages of Examples 1 - 3: Example 3 has the best comprehensive performance: the lowest water absorption rate (0.9%), the highest compressive strength (48 MPa), the best hydrophobicity (contact angle of 152°), and the smallest performance decay after aging (compressive strength of 43 MPa after 14 days), indicating that the synergistic effect between the steel slag core and the high-ratio additives (hydrogen peroxide, rock salt, etc.) is significant.

[0085] (2)The role of hydrogen peroxide (comparing Example 1 and Comparative Example 1): The ice melting efficiency of Comparative Example 1 without hydrogen peroxide is only 65%, while that of Example 1 reaches 92%, indicating that hydrogen peroxide enhances the ice melting activity by increasing the porosity of the aggregate through oxidation reaction.

[0086] 2. Influence of the hydrophobic layer (comparing Example 1 and Comparative Example 2): In Comparative Example 2 without spraying the hydrophobic layer, the water absorption rate is as high as 4.5%, the contact angle is only 50°, and the wear resistance loss rate is 15%, which is much lower than that of Example 1 (water absorption rate of 1.2%, contact angle of 145°), proving that the silicone resin hydrophobic layer significantly improves water penetration resistance and wear resistance.

[0087] 3. Superiority of the steel slag core (comparing Example 3 and Comparative Example 3): In Comparative Example 3 using natural sand and gravel, the compressive strength (35 MPa) is lower than that of Example 3 (48 MPa), and the ice melting efficiency is only 75%, indicating that the rough surface and high hardness characteristics of the steel slag are more conducive to mechanical interlocking and the release of deicing agents.

[0088] 4. Environmental protection and economy: All examples utilize solid wastes (such as steel slag and coal fly ash), and the water absorption rate and strength meet the standards, meeting the green building material standards. The insufficient performance of Comparative Example 1 without using hydrogen peroxide proves that reasonable proportioning is the key to balancing environmental protection and performance.

[0089] The above shows and describes the basic principles, main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

Claims

1. A solid waste-based artificial aggregate for ice melting and anti-skidding on winter road surfaces, characterized in that: The described solid waste-based artificial aggregate adopts a multi-layer composite structure, including a core, an intermediate layer, and an outer layer. By weight: Core: 50 - 70 parts, with a particle size of 2 - 6 mm, which is steel slag with a rough surface and irregular shape; Intermediate layer: 70 - 120 parts, a slow-release composite layer composed of the following components: 1 - 3 parts of hydrogen peroxide foaming agent, 15 - 25 parts of coal combustion fly ash, 10 - 20 parts of calcium sulfate waste residue, 5 - 10 parts of slag micro-powder, 20 - 30 parts of rock salt with a NaCl content ≥ 95%, 20 - 30 parts of slag cement; Outer layer: 1 - 2 parts of an organosilicon resin hydrophobic layer with a thickness of 0.1 - 0.3 mm.

2. The solid waste-based artificial aggregate according to claim 1, wherein The described coal combustion fly ash conforms to the Class F or Class C standard in GB / T1596 - 2017: SiO2 + Al2O3 + Fe2O3 ≥ 70% (Class F) or ≥ 50% (Class C), and the unburned carbon content ≤ 5%; the calcium sulfate waste residue has a CaSO4 content ≥ 80% (calculated as dihydrate or hemihydrate calcium sulfate), an impurity content ≤ 10%, and a pulverized particle size ≤ 0.15 mm.

3. The solid waste-based artificial aggregate according to claim 1, wherein The described slag micro-powder meets the requirements: specific surface area ≥ 450 m² / kg, SiO2 + Al2O3 ≥ 65%, metal oxide impurities ≤ 3%, and the particle size distribution is 1 - 45 μm; the slag cement conforms to GB / T 18046 - 2017, with a slag content ≥ 70% and a specific surface area ≥ 400 m² / kg.

4. The solid waste-based artificial aggregate according to claim 1, wherein The thickness of the intermediate layer is 0.5 - 1.5 mm, and the porosity is 20% - 35%. The intermediate layer is formed through the following process: (1) Curing reaction for 2 - 4 hours under the conditions of a temperature of 40 - 60 °C and a relative humidity of 60% - 80%; (2) Transfer the cured intermediate layer aggregate to a microwave reactor and conduct microwave activation treatment for 5 - 10 minutes at a microwave frequency of 2.4 - 2.5 GHz and a power of 500 - 800 W.

5. The solid waste-based artificial aggregate according to claim 1, characterized in that, The processing method of the outer layer is as follows: Uniformly spray a 5% - 10% organosilicon resin hydrophobic material through a spray gun at a pressure of 0.3 - 0.5 MPa, a spraying distance of 15 - 20 cm, and a hydrophobic surface contact angle ≥ 150° to form an outer layer hydrophobic layer with a thickness of 0.1 - 0.3 mm.

6. The preparation method of the solid waste-based artificial aggregate according to any one of claims 1 to 5, characterized in that, It includes the following steps: A. Core pretreatment: (1) Vibration screening to select irregular steel slag with a particle size of 2 - 6 mm; (2) Pickling to remove surface oxides; (3) Drying at 80 - 100 °C until the moisture content < 0.5%; B. Intermediate layer construction: (1) Dry-mix the foaming agent, coal combustion fly ash, calcium sulfate waste residue, slag micro-powder, rock salt, slag cement, etc., and then add water to make a mixed slurry with a solid content of 60% - 70%; (2) Wrap the steel slag core with the mixed slurry and cure for 2 - 4 hours under the conditions of a temperature of 40 - 60 °C and a humidity of 60% - 80%; (3) Transfer the cured intermediate layer aggregate to a microwave reactor and conduct microwave activation treatment for 5 - 10 minutes at a microwave frequency of 2.4 - 2.5 GHz and a power of 500 - 800 W; C. Outer layer modification: Spray the hydrophobic aqueous solution of silicone resin with a concentration of 5% - 10% on the surface of the aggregate of the constructed intermediate layer at a pressure of 0.3 - 0.5 Mpa and a distance of 15 - 20 cm to form a hydrophobic layer with a thickness of 0.1 - 0.3 mm, and air-dry at room temperature.

7. The preparation method of the solid waste-based artificial aggregate according to claim 6, characterized in that: The conditions of the microwave activation treatment are: microwave frequency 2.4 - 2.5 GHz, power 500 - 800 W, activation treatment time 5 - 10 minutes, and the material temperature is controlled at 50 - 70 °C.

8. The preparation method of the solid waste-based artificial aggregate according to claim 6, wherein: The calcium sulfate waste residue comes from the waste of rock salt production. The wet residue is collected by centrifugal separation or plate and frame filtration, and the wet residue is obtained by drying at 100 - 150 °C and then pulverizing.

9. The preparation method of the solid waste-based artificial aggregate according to claim 6, characterized in that: The coal fly ash is the fly ash collected from the flue gas of the coal-fired boiler during the rock salt production process after dust removal.

10. Use of the solid waste-based artificial aggregate according to any one of claims 1 to 5, characterized in that: It is used for ice melting and anti-skid on winter roads, bridges or airport runways. Its ice melting component is rock salt, which is slowly released to the road surface through the pores of the intermediate layer, and the release period matches the snowfall frequency.

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