Slow-release ice-melting asphalt mixture based on carbon-reinforced solid-waste-based artificial aggregate and preparation method of slow-release ice-melting asphalt mixture

Abstract

The invention discloses a slow-release ice-melting asphalt mixture based on a carbon-reinforced solid waste-based artificial aggregate and a preparation method of the slow-release ice-melting asphalt mixture. The mixture comprises the following components in parts by weight: 120-140 parts of the carbon-reinforced solid waste-based artificial aggregate and 6-8 parts of diatomite modified asphalt, the carbon reinforced solid waste based artificial aggregate comprises 105-115 parts of concrete recycled micro powder, 8-15 parts of snow melting salt and 7-10 parts of cement; the snow melting salt is prepared by mixing salt rock-based sodium chloride and sodium acetate according to the weight ratio of 6: 4. The asphalt mixture can store salt and slowly release snow melting salt when meeting water, so that the ice melting effect is achieved; the snow melting salt can be adsorbed into the asphalt mixture again through capillary adsorption after rainwater stops, so that the snow melting efficiency is improved; the carbonization treatment enhances the strength of the aggregate and the bonding performance of the aggregate and asphalt. The concrete is suitable for winter pavements in cold regions, has good ice melting, durability and environmental protection properties, obviously prolongs the service life of roads, and promotes efficient utilization of solid waste resources.

Description

Technical Field

[0001] The present invention relates to the technical field of road construction materials, and in particular to a slow-release ice-melting asphalt mixture prepared based on carbon-reinforced solid waste-based artificial aggregate and a preparation method thereof, which is suitable for the functions of ice melting and anti-freezing cracking of winter roads in cold regions. Background Art

[0002] With the intensification of global climate change, cold regions are facing increasingly severe problems of snowfall and low temperatures in winter. This not only poses a huge challenge to traffic safety, but also puts higher requirements on road maintenance. In terms of traffic safety, ice-covered roads will significantly reduce the adhesion between vehicle tires and the ground, thereby increasing the braking distance and greatly increasing the risk of traffic accidents. Especially in areas where the temperature fluctuates frequently, ice and snow melt first and then quickly refreeze to form "black ice" roads. This thin ice is almost transparent and extremely difficult for drivers to detect, which further increases the danger of driving. Under such severe weather conditions, road capacity is severely reduced, traffic jams and accidents occur frequently, and even have a negative impact on the normal development of social and economic activities. From the perspective of road maintenance, repeated freeze-thaw cycles will accelerate the aging of road materials and shorten the service life of roads. Therefore, how to effectively remove ice and snow from the road, ensure traffic safety, and extend the durability of the road has become a key issue that needs to be urgently solved in winter road maintenance in cold regions.

[0003] At present, the main measures for road deicing in winter are spreading deicing salt and developing salt-storing asphalt mixtures. However, the traditional method of spreading deicing salt has many disadvantages, such as short-term deicing effect, serious waste of deicing salt, pollution to the environment, and corrosion to road materials.

[0004] With the improvement of environmental awareness, the recycling of solid waste resources has received more and more attention. Through pressureless agglomeration technology, solid waste resources (such as recycled concrete powder, steel slag powder, etc.) can be combined with cement to prepare artificial aggregates. These artificial aggregates can not only replace natural aggregates in asphalt mixtures, but also have advantages in environmental protection and cost control. The main chemical composition of solid waste-based artificial aggregates is calcium silicate hydrate gel (CSH), and its rich nano-scale microporous structure can effectively store and slowly release snow-melting salt to achieve the effect of continuous ice melting. However, although the microporous structure of solid waste-based artificial aggregates has obvious advantages in storing and slowly releasing snow-melting salt, it also brings new challenges. Due to the high porosity of these aggregates, their low strength, and the poor adhesion between aggregates and asphalt, their application in asphalt mixtures is limited. This makes traditional asphalt mixtures prone to rutting, aggregate shedding and other phenomena during use, affecting the use effect of the pavement. Summary of the invention

[0005] The technical problem to be solved by the present invention is: aiming at the deficiencies in the prior art, to provide a slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregates and its preparation method, which is used to solve the problems that traditional road snow melting and deicing measures have an adverse impact on the road environment and the stability of asphalt mixtures.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0007] A slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregates, in parts by weight, includes 120-140 parts of carbon-strengthened waste-based artificial aggregates and 6-8 parts of diatomite-modified asphalt; the carbon-strengthened waste-based artificial aggregates include 105-115 parts of concrete recycled fine powder, 8-15 parts of snow-melting salt, and 7-10 parts of cement; the snow-melting salt is prepared by mixing rock salt-based sodium chloride and sodium acetate in a weight ratio of 6:4.

[0008] The diatomite-modified asphalt is a composite material prepared based on matrix asphalt by adding diatomite through uniform dispersion and high-temperature shear mixing. The diatomite content is 16%-20% of the mass of the matrix asphalt, its softening point is 60-75°C, the ductility at 5°C is 50-80 cm, and the penetration at 25°C is 40×0.1 mm-60×0.1 mm, meeting the requirements of the "Technical Specification for Highway Asphalt Pavement Construction".

[0009] The concrete recycled fine powder is obtained by initially crushing waste concrete blocks with a jaw crusher, classifying and screening with a vibrating screen (the particle size of the first-stage screening is less than 2.36 mm, and the particle size of the second-stage screening is less than 1.5 mm), and then grinding.

[0010] The Ca / Si molar ratio of the concrete recycled fine powder is 0.8-1.2, the particle size range is 0.075-0.15 mm, and the specific surface area is 0.45-0.65 m 2 / g.

[0011] The rock salt-based sodium chloride is obtained by crushing rock salt, screening (the particle size is less than 0.3 mm), and drying (the temperature is controlled at 105±5°C for 3 hours). The purity of the rock salt-based sodium chloride is above 95%, the particle size range is 0.1-0.3 mm, and the moisture content is less than 0.5%.

[0012] The sodium acetate is sodium acetate particles with a purity of above 98% and a particle size of 0.1-0.3 mm.

[0013] The cement is ordinary Portland cement of P·O42.5, with a specific surface area of 330-360 m 2 / kg, the standard consistency water consumption is 25.0%-27.0%, and the initial setting time is not less than 45 minutes.

[0014] The preparation method of the slow-release ice-melting asphalt mixture based on carbon-strengthened solid waste-based artificial aggregate described above includes the following specific steps:

[0015] A. Preparation of environmentally friendly salt rock-based snow melting salt:

[0016] (1) Feed the salt rock raw material into a jaw crusher for preliminary crushing;

[0017] (2) Use a vibrating screen to screen out salt rock particles with a particle size of 0.1 - 0.3 mm;

[0018] (3) Dry the salt rock particles in an oven at a temperature of 105 ± 5 °C for 3 - 4 hours, and obtain salt rock-based sodium chloride for standby after cooling;

[0019] (4) Mix the dried salt rock-based sodium chloride and sodium acetate in a weight ratio of 6:4 to obtain the environmentally friendly salt rock-based snow melting salt;

[0020] B. Preparation of concrete recycled fine powder:

[0021] (1) Crush the waste concrete blocks with a jaw crusher to a particle size less than 5 mm;

[0022] (2) Use a vibrating screen to screen and obtain powder with a particle size less than 0.15 mm;

[0023] (3) Grind the screened powder with a grinder until the specific surface area reaches 0.45 - 0.65 m 2 / g of fine powder for standby.

[0024] C. Preparation of carbon-strengthened solid waste-based artificial aggregate:

[0025] (1) By weight, mix 105 - 115 parts of concrete recycled fine powder, 8 - 15 parts of environmentally friendly salt rock-based snow melting salt, and 7 - 10 parts of cement, and stir evenly;

[0026] (2) Use a disk granulator with a model of Φ2.5 m × 10 m for granulation, control the rotation speed at 20 - 30 rpm, the water addition amount at 8% - 10% of the total material amount, and the granulation time at 15 - 20 minutes to form aggregates with a particle size of 2 - 5 mm;

[0027] (3) Place the granulated aggregates in a carbonization device, under an atmosphere with a concentration of 5% - 10% of CO 2 control the humidity at 70% - 90%, the temperature at 20 - 25 °C, and the carbonization time at 32 - 40 hours for standby;

[0028] D. Preparation of diatomite-modified asphalt:

[0029] Based on the base asphalt, adding diatomite accounting for 16% - 20% of the mass of the base asphalt, and obtaining diatomite-modified asphalt after uniform dispersion and high-temperature shear mixing;

[0030] E. Preparation of slow-release ice-melting asphalt mixture:

[0031] (1) Mix 120 - 140 parts of carbon-strengthened waste-based artificial aggregate with 6 - 8 parts of diatomite-modified asphalt according to the above weight parts;

[0032] (2) Stir in a mixer at a temperature of 170 - 180 °C for 8 - 10 minutes, with a stirring speed of 50 - 60 rpm, to ensure that the surface of the aggregate is evenly coated with asphalt;

[0033] (3) After stirring is completed, cool the mixture to obtain a slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate.

[0034] After preparation, the slow-release ice-melting asphalt mixture prepared by the present invention has excellent performance and can meet the relevant requirements of the "Test Procedures for Road Asphalt and Asphalt Mixtures" (JTGE20 - 2011).

[0035] In the present invention, first, concrete recycled fine powder with a particle size range within 1.5 mm is selected by screening as the main raw material. On this basis, a small amount of cement and a certain proportion of snow-melting salts (including rock salt-based sodium chloride and sodium acetate) are incorporated, mixed evenly, and a salt-storing slow-release artificial aggregate is prepared by using a disk granulator under a non-pressure agglomeration technique to coordinate each component. Among them, the waste recycled fine powder, as an important raw material, can significantly improve the microstructural stability of the artificial aggregate and provide more microporous structures for storing snow-melting salts; the cement provides a certain strength for the artificial aggregate, forms a dense gel skeleton through hydration reaction, and further enhances the bearing capacity and compressive resistance of the aggregate; the snow-melting salt component can significantly improve the slow-release ice-melting performance of the aggregate by being evenly distributed in the micropores of the aggregate, ensuring the continuous anti-slip and snow-melting effects of the road surface under low-temperature conditions.

[0036] The present invention innovatively introduces a carbonization treatment step. By curing the artificial aggregate under certain concentration of CO 2 conditions, CaCO 3 is deposited on the surface of the aggregate, enhancing its hardness and chemical stability. The carbonized aggregate not only has higher compressive strength but also improves its adhesion to asphalt, avoiding the problems of poor compatibility and easy separation between the snow-melting salt and the asphalt component in traditional salt-storing asphalt mixtures, thereby improving the comprehensive performance and durability of the material.

[0037] The present invention uses a solid waste-based artificial aggregate prepared by synergistically combining snow melting salt, solid waste fine powder, and cement as a salt storage carrier, replacing natural aggregates and applying them to asphalt mixtures. Due to the rich microporous structure of the artificial aggregate, when rain or snow weather comes, moisture will seep into the pores of the artificial aggregate, and the snow melting salt will gradually dissolve and release in the pores, thus providing a snow melting effect slowly and continuously. Through this slow release mechanism, the freezing phenomenon of pore water in the asphalt mixture at temperatures of -10 to 0 °C can be effectively avoided, thereby preventing freeze-thaw damage caused by the volume expansion of water turning into ice, and significantly improving the durability and frost resistance of asphalt mixtures in cold regions. To further enhance the functions of the asphalt mixture, the present invention introduces diatomite-modified asphalt. Diatomite has a large specific surface area and good capillary adsorption, which significantly improves the mass transfer ability of moisture and salt solution in the asphalt mixture as a transmission medium. In rain or snow weather, the diatomite-modified asphalt provides a channel for moisture to enter the artificial aggregate and dissolve the salt, ensuring the slow release of the salt solution; after the rain or snow weather ends, the diatomite re-adsorbs the salt back into the aggregate pores through capillary action to maintain its snow melting energy efficiency. The addition of diatomite also further optimizes the interfacial properties between the asphalt and the aggregate, improving the comprehensive stability of the mixture.

[0038] The slow-release ice melting asphalt mixture based on carbon-strengthened solid waste-based artificial aggregate prepared by the present invention shows great technical advantages, especially in aspects such as slow-release snow melting, freeze-thaw damage resistance, and improvement of the stability of asphalt mixtures. The aggregate prepared by the pressureless agglomeration process is carbon-strengthened, having good physical stability and good compatibility with asphalt, and can effectively avoid the detachment of the snow melting salt from the asphalt mortar, enabling it to maintain high strength and stability during long-term use. The present invention enhances the durability of the asphalt mixture, especially suitable for the extreme climate conditions in cold regions, providing an efficient and environmentally friendly solution for winter road maintenance. At the same time, the present invention provides a more sustainable development path for the resource utilization of solid waste and road construction and maintenance.

[0039] The main principle of the present invention is as follows:

[0040] 1. The basic principle of preparing artificial aggregate by synergistically combining solid waste fine powder and snow melting salt:

[0041] Construction solid waste fine powder is rich in calcium oxide (CaO), silicon oxide (SiO 2 ) and other metal ions, having strong hydrophilicity and high chemical reaction activity. During the hydration process, the solid waste fine powder can generate calcium silicate hydrate gel (C-S-H), and calcium hydroxide (Ca(OH) 2) Compounds such as these further promote the bonding between the solid waste fine powder and other components, forming a more compact aggregate structure. The snow melting salts (such as sodium acetate and sodium chloride) have stable components and are not prone to chemical reactions. They can be fully integrated with the hydration products of cement and recycled fine powder through the pressureless agglomeration granulation technology to achieve the salt storage function of artificial aggregates. The silica and aluminates in cement react with metal ions in the fine powder through hydration reactions, further enhancing the strength and stability of the aggregates and providing an ideal framework for the subsequent carbonization process.

[0042] 2. Enhancement mechanism of carbonization-strengthened solid waste-based artificial aggregates:

[0043] During the process of preparing artificial aggregates from solid waste fine powder and cement, the C-S-H generated by the hydration reaction therein and a small amount of unreacted Ca(OH) 2 , will react with carbon dioxide (CO 2 ), to generate calcium carbonate (CaCO 3 ). This reaction not only enhances the chemical stability of the aggregates, but also forms a dense carbonate layer on the surface of the aggregates, further improving its hydrophilicity and stability. The formation of calcium carbonate effectively fills the micropores on the surface of the aggregates, increases the surface compactness, and thus improves the compressive strength and anti-stripping performance of the aggregates. In addition, the increase in micropores on the surface of the aggregates during the carbonization process enhances physical forces such as hydrogen bonds and van der Waals forces, thereby improving the adhesion between the aggregates and asphalt and effectively preventing the shedding and cracking of asphalt in low-temperature environments.

[0044] 3. Salt storage-slow release-re-adsorption mechanism of ice-melting asphalt mixture:

[0045] The solid waste fine powder-based aggregates form a porous structure and a dense carbonate layer through activation and carbonization treatments, providing a stable carrier for the storage and release of snow melting salts. The pores of the aggregates attract water and salts through capillary action, dissolve the salts and slowly release them during precipitation, and then re-store the salts after the evaporation of water using the capillary re-absorption function to achieve cyclic ice melting. The introduction of diatomite-modified asphalt further enhances this mechanism. Diatomite optimizes the transmission path of salts in the asphalt mixture by virtue of its high specific surface area and excellent adsorption performance. At the same time, its good hygroscopicity promotes the re-adsorption and introduction of environmental moisture, improving the continuous utilization efficiency of salts. The microporous structure of diatomite and the pores of the aggregates act synergistically to effectively delay the salt release rate, avoid the rapid loss of salts or environmental erosion, and improve the uniformity of salt distribution, enhancing the overall slow release performance of the material.

[0046] 4. Principle of anti-freezing and thawing damage and improvement of asphalt pavement durability:

[0047] The present invention provides a slow-release salt function by using carbide-strengthened solid waste-based artificial aggregates, effectively avoiding the volume expansion effect generated when water freezes in a low-temperature environment. The slow release of the snow-melting salt can lower the freezing point of water before the water freezes, thus avoiding the freeze-thaw damage caused by the freezing of water. In addition, the surface of the aggregate after carbonization increases the intermolecular binding forces such as hydrogen bonds and van der Waals forces, enhancing the adhesion between the asphalt and the aggregate, and reducing the separation and shedding between the asphalt and the aggregate in a low-temperature environment. Combining with the slow-release characteristics of the snow-melting salt, the asphalt mixture can maintain excellent mechanical properties and frost resistance during temperature fluctuations, thereby improving the durability and safety of the road.

[0048] In the present invention, the reaction principle equations involved in the aggregate preparation process are as follows:

[0049] 1. Dissolution reaction of silicate SiO 2 +2OH - →SiO 3 2- +H 2 O

[0050] 2. Dissolution reaction of aluminate Al 2 O 3 +2OH - +3H 2 O→2Al(OH) 4 -

[0051] 3. Dissolution and reaction of calcium CaO+H 2 O→Ca(OH) 2

[0052] Ca(OH) 2 +SiO 3 2- +H 2 O→C-S-H (calcium silicate hydrate)

[0053] 4. Formation of NASH gel Na + +SiO 3 2- +Al(OH) 4 - +H 2 O→N-A-S-H (hydrated sodium aluminosilicate)

[0054] 5. Formation of calcium carbonate (side reaction) Ca(OH) 2 +CO 2 →CaCO 3 +H 2 O

[0055] 6. Further water absorption is manifested as (water adsorbed in CSH and NASH gels):

[0056] C-S-H + H 2 O → C-S-H·H 2 O

[0057] N-A-S-H + H 2 O → N-A-S-H·H 2 O

[0058] Among them, the adsorbed water will exist in the form of physically adsorbed water or chemically bound water.

[0059] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0060] 1. Resource utilization of solid waste fine powder and green and efficient preparation of artificial aggregate:

[0061] Through the synergistic action of construction solid waste fine powder, snow melting salt and low-dosage cement, the present invention innovatively realizes the efficient resource utilization of construction solid waste. As one of the main components, the solid waste fine powder has strong hydrophilicity and significant chemical reaction activity due to the rich metal ions such as calcium oxide (CaO) and silicon dioxide (SiO 2 ) on its surface. During the hydration process, the solid waste fine powder can not only generate calcium silicate hydrate gel (C-S-H) to enhance the structural strength of the aggregate, but also generate compounds such as calcium hydroxide (Ca(OH) 2 ), which further promote the combination and condensation of other components in the aggregate and provide a solid physical basis for the subsequent carbonation reaction. In this process, the addition of snow melting salts (such as sodium acetate and sodium chloride) has stable chemical properties and does not participate in the hydration reaction. However, through the non-pressure adhesion granulation technology, the snow melting salts can jointly generate a gelling material with cement and solid waste fine powder and effectively embed in the aggregate, endowing the artificial aggregate with excellent salt storage function. This technology realizes the green and efficient recycling of solid waste fine powder, not only avoiding environmental pollution of waste, but also achieving the goal of low-cost and high-efficiency production of artificial aggregate, providing a sustainable development path for the resource utilization of construction solid waste.

[0062] 2. Carbonized solid waste-based artificial aggregate improves performance:

[0063] During the carbonation process of the aggregate, the C-S-H gel and calcium hydroxide generated by the reaction of the solid waste fine powder with silicon dioxide and aluminate in the cement and metal ions further react with CO 2 to generate calcium carbonate (CaCO 3) This process not only enhances the mechanical strength and surface stability of the aggregate, but also forms a dense carbonate layer on the surface of the aggregate, significantly improving its hydrophilicity and chemical stability. The formation of calcium carbonate fills the tiny pores on the surface of the aggregate, enhancing its compressive and anti-stripping abilities, thereby providing a more stable surface foundation for the adhesion of asphalt. In addition, the calcium carbonate layer generated in the carbonation reaction and the strong hydrogen bonds and van der Waals forces on the surface of the aggregate further promote the affinity between asphalt and aggregate, making the bond between asphalt and aggregate more firm. This technology not only improves the compatibility between aggregate and asphalt, but also effectively avoids the separation and cracking between asphalt and aggregate in low-temperature environments, greatly improving the stability and durability of the road surface under severe cold conditions.

[0064] 3. Green and environmentally friendly slow-release ice-melting asphalt mixture and freeze-thaw resistance performance:

[0065] The solid waste-based artificial aggregate proposed in the present invention has excellent slow-release salt function, which can effectively store and slowly release snow-melting salt. During precipitation, it adsorbs and releases snow-melting salt through capillary action, and re-adsorbs salt after the rainwater evaporates. This slow-release process not only prolongs the ice-melting effect of the road surface, but also effectively reduces the negative impact of snow-melting salt on the environment, avoiding the pollution of soil, groundwater and plants caused by the traditional salt-spreading method. In addition, based on the carbonation strengthening technology of solid waste micro-powder, the present invention can effectively reduce the freeze-thaw damage of water in low-temperature environments. The slow release of snow-melting salt reduces the freezing point of water, avoiding the structural damage caused by freezing expansion. At the same time, the surface of the carbonated aggregate enhances the bonding force between asphalt and aggregate, enabling the asphalt mixture to still maintain excellent mechanical properties and freeze-thaw resistance under temperature fluctuations and freeze-thaw cycles. Brief Description of the Drawings

[0066] In order to more clearly illustrate the technical solution of the present invention, the drawings in the present invention will be briefly introduced below. By reading the following drawings, the technical features, objectives and advantages of the present invention will become more obvious:

[0067] Figure 1 It is a schematic diagram of the salt storage and slow-release function based on capillary adsorption in the principle of the present invention;

[0068] Figure 2 It is a schematic diagram of preparing the slow-release ice-melting asphalt mixture in the present invention;

[0069] Figure 3 It is a schematic diagram of the molecular dynamics simulation of adsorbing and slowly releasing snow-melting salt in the present invention. Detailed Embodiments

[0070] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0071] Embodiment: A slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate, by weight, includes 120-140 parts of carbon-strengthened waste-based artificial aggregate and 6-8 parts of diatomite-modified asphalt; the carbon-strengthened waste-based artificial aggregate includes 105-115 parts of concrete recycled fine powder, 8-15 parts of snow-melting salt and 7-10 parts of cement; the snow-melting salt is prepared by mixing rock-salt-based sodium chloride and sodium acetate in a weight ratio of 6:4.

[0072] The diatomite-modified asphalt is a composite material prepared based on matrix asphalt by adding diatomite and uniformly dispersing and high-temperature shearing mixing. The diatomite content is 16%-20% of the mass of the matrix asphalt, its softening point is 60-75°C, the ductility at 5°C is 50-80 cm, and the penetration at 25°C is 40×0.1 mm-60×0.1 mm.

[0073] The Ca / Si molar ratio of the concrete recycled fine powder is 0.8-1.2, the particle size range is 0.075-0.15 mm, and the specific surface area is 0.45-0.65 m 2 / g.

[0074] The rock-salt-based sodium chloride is obtained by crushing, screening and drying rock salt. The purity of the rock-salt-based sodium chloride is above 95%, the particle size range is 0.1-0.3 mm, and the water content is less than 0.5%.

[0075] The sodium acetate is sodium acetate particles with a purity of above 98% and a particle size of 0.1-0.3 mm.

[0076] The cement is ordinary Portland cement P·O42.5, the specific surface area is 330-360 m 2 / kg, the standard consistency water consumption is 25.0%-27.0%, and the initial setting time is not less than 45 minutes.

[0077] The preparation method of the above-mentioned slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate includes the following specific steps:

[0078] A. Preparation of environment-friendly rock-salt-based snow-melting salt:

[0079] (1) Feed the rock salt raw material into a jaw crusher for preliminary crushing;

[0080] (2) Use a vibrating screen to screen out salt rock particles with a particle size of 0.1 - 0.3 mm;

[0081] (3) Dry the salt rock particles in an oven at a temperature of 105 ± 5 °C for 3 - 4 hours, and obtain the salt rock-based sodium chloride for standby after cooling;

[0082] (4) Mix the dried salt rock-based sodium chloride and sodium acetate in a weight ratio of 6:4 to obtain an environmentally friendly salt rock-based deicing salt;

[0083] B. Preparation of recycled concrete fine powder:

[0084] (1) Crush the waste concrete blocks with a jaw crusher to a particle size less than 5 mm;

[0085] (2) Use a vibrating screen to screen and obtain a powder with a particle size less than 0.15 mm;

[0086] (3) Grind the screened powder with a grinder until the specific surface area reaches 0.45 - 0.65 m 2 / g of fine powder for standby.

[0087] C. Preparation of carbon-strengthened waste-based artificial aggregate:

[0088] (1) By weight, mix 105 - 115 parts of recycled concrete fine powder, 8 - 15 parts of environmentally friendly salt rock-based deicing salt, and 7 - 10 parts of cement, and stir evenly;

[0089] (2) Use a disk granulator with a model of Φ2.5 m × 10 m for granulation, control the rotation speed at 20 - 30 rpm, the water addition amount is 8% - 10% of the total material amount, and the granulation time is 15 - 20 minutes to form an aggregate with a particle size of 2 - 5 mm;

[0090] (3) Place the granulated aggregate in a carbonization device, in an atmosphere with a concentration of 5% - 10% of CO 2 , control the humidity at 70% - 90%, the temperature at 20 - 25 °C, and the carbonization time at 32 - 40 hours for standby;

[0091] D. Preparation of diatomite-modified asphalt:

[0092] Based on the matrix asphalt, add 16% - 20% of diatomite by the mass of the matrix asphalt, and obtain diatomite-modified asphalt after uniform dispersion and high-temperature shear mixing;

[0093] E. Preparation of slow-release ice-melting asphalt mixture:

[0094] (1) Mix 120 - 140 parts of carbon-strengthened waste-based artificial aggregate and 6 - 8 parts of diatomite-modified asphalt according to the above weight parts;

[0095] (2) Stir in a mixer at a temperature of 170 - 180 °C for 8 - 10 minutes, with a stirring speed of 50 - 60 rpm, to ensure that the surface of the aggregate is evenly coated with asphalt;

[0096] (3) After stirring is completed, cool the mixture to obtain a slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate.

[0097] After preparation, the slow-release ice-melting asphalt mixture prepared by the present invention has excellent performance and can meet the relevant requirements of the "Test Regulations for Road Asphalt and Asphalt Mixtures" (JTGE20 - 2011).

[0098] 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.

[0099] Example 1:

[0100] This example provides a slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate. Calculated by weight, it includes 120 parts of carbon-strengthened waste-based artificial aggregate and 8 parts of diatomite-modified asphalt. The carbon-strengthened waste-based artificial aggregate is prepared and carbonized and cured by the non-pressure agglomeration technology, and by weight, it includes: 105 parts of concrete recycled fine powder, 8 parts of environmentally friendly salt rock-based snow melting salt, and 7 parts of cement.

[0101] The preparation process of the above-mentioned slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate includes the following steps:

[0102] Step 1, crush, screen, and grind the recovered waste concrete blocks; among them, the discharge port size of the crusher is set to 5 mm, the first-stage vibrating screen mesh is 2.36 mm, and the second-stage screening is 1.5 mm.

[0103] Step 2, crush, screen, dry, and cool the mined salt rock; among them, the screening process is: use a vibrating screen to screen out salt rock particles with a particle size of 0.1 - 0.3 mm, the drying temperature is 105 ± 5 °C, and the drying time is 3 h.

[0104] Step 3, mix and stir evenly 105 parts of concrete recycled fine powder, 3 parts of sodium chloride, 5 parts of sodium acetate, and 7 parts of cement.

[0105] Step 4, use a disk granulator with a model of Φ2.5m×10m to granulate to form aggregates with a particle size of 2 - 5 mm; the rotation speed of the disk granulator is controlled at 20 - 30 rpm, the water addition amount during the granulation process is 8% - 10% of the total material amount, and the granulation time is 15 minutes.

[0106] Step 5: Place the granulated aggregate in a carbonization device for carbonization curing, and then take it out for standby; during carbonization curing, the CO 2 concentration is 5% - 10%, the carbonization humidity is controlled at 70% - 90%, the temperature is 20 - 25 °C, and the carbonization time is 36 hours.

[0107] Step 6: Mix 120 parts of carbon-strengthened waste-based artificial aggregate and 8 parts of diatomite-modified asphalt by the above weight parts and place them in a mixer for stirring until the surface of the aggregate is evenly coated with asphalt; among them: the mixing temperature is 170 - 180 °C, the stirring time is 8 - 10 minutes, and the stirring speed is set at 50 - 60 rpm.

[0108] Step 7: After the mixing of the mixture is completed, pour the mixture into a mold for cooling and forming.

[0109] For the slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate prepared according to the above steps, measure its relevant performance indicators. The specific index parameters are shown in Table 1 and Table 2.

[0110] Example 2:

[0111] This example provides a slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate. Calculated by weight parts, it includes 140 parts of carbon-strengthened waste-based artificial aggregate and 6 parts of diatomite-modified asphalt. The carbon-strengthened waste-based artificial aggregate is prepared and carbonization-cured by the pressureless agglomeration technology, and by weight parts, it includes: 115 parts of concrete recycled fine powder, 15 parts of environmentally friendly salt rock-based snow-melting salt, and 10 parts of cement.

[0112] In this example, the preparation process of the slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate is basically the same as that of Example 1, and the difference is only in the preparation according to the formula of this example.

[0113] For the slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate prepared according to the above steps, measure its relevant performance indicators. The specific index parameters are shown in Table 1 and Table 2.

[0114] Example 3:

[0115] This example provides a slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate. Calculated by weight parts, it includes: 137 parts of carbon-strengthened waste-based artificial aggregate and 6 parts of diatomite-modified asphalt. The carbon-strengthened waste-based artificial aggregate is prepared and carbonization-cured by the pressureless agglomeration technology, and by weight parts, it includes: 115 parts of concrete recycled fine powder, 15 parts of environmentally friendly salt rock-based snow-melting salt, and 7 parts of cement.

[0116] In this embodiment, the preparation process of the slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate is basically the same as that of Example 1, except that it is prepared according to the formula of this embodiment.

[0117] For the slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate prepared according to the above steps, measure its relevant performance indicators. The specific index parameters are shown in Table 1 and Table 2.

[0118] Comparative Example 1:

[0119] This comparative example provides a slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate. Calculated by weight, it includes: 120 parts of carbon-strengthened waste-based artificial aggregate and 8 parts of diatomite-modified asphalt. The carbon-strengthened waste-based artificial aggregate is prepared and carbonized and cured by the non-pressure agglomeration technology. Calculated by weight, it includes: 113 parts of concrete recycled fine powder and 7 parts of cement.

[0120] In this comparative example, the preparation process of the slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate is basically the same as that of Example 1, except that no environmentally friendly salt rock-based snowmelt salt is added.

[0121] For the slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate prepared according to the above steps, measure its relevant performance indicators. The specific index parameters are shown in Table 1 and Table 2.

[0122] Comparative Example 2:

[0123] This comparative example provides a slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate. Calculated by weight, it includes: 130 parts of carbon-strengthened waste-based artificial aggregate and 8 parts of diatomite-modified asphalt. The carbon-strengthened waste-based artificial aggregate is prepared and carbonized and cured by the non-pressure agglomeration technology. Calculated by weight, it includes: 115 parts of concrete recycled fine powder and 15 parts of environmentally friendly salt rock-based snowmelt salt.

[0124] In this comparative example, the preparation process of the slow-release ice-melting asphalt mixture based on carbon-strengthened waste-based artificial aggregate is basically the same as that of Example 1, except that no cement is added.

[0125] For the slow-release ice-melting asphalt mixture prepared from carbon-strengthened waste-based artificial aggregate prepared according to the above steps, measure its relevant performance indicators. The specific index parameters are shown in Table 1 and Table 2.

[0126] Comparative Example 3:

[0127] This comparative example presents a slow-release ice-melting asphalt mixture based on carbon-strengthened solid waste-based artificial aggregates. Calculated by weight, it includes: 137 parts of solid waste-based artificial aggregates and 6 parts of diatomite-modified asphalt. The solid waste-based artificial aggregates are prepared using the non-pressure agglomeration technology and, by weight, include: 115 parts of concrete recycled fine powder, 15 parts of environmentally friendly salt rock-based snow-melting salt, and 7 parts of cement.

[0128] The preparation process of the slow-release ice-melting asphalt mixture based on solid waste-based artificial aggregates in this comparative example is basically the same as the preparation method in Example 1, except that the solid waste-based artificial aggregates are not carbonized and strengthened.

[0129] The slow-release ice-melting asphalt mixture prepared from carbon-strengthened solid waste-based artificial aggregates according to the above steps is measured for its relevant performance indicators. The specific indicator parameters are shown in Tables 1 and 2 below.

[0130] Table 1 Basic physical performance indicators of asphalt mixtures in each example and comparative example of the present invention

[0131]

[0132] Table 2 Durability performance indicators of asphalt mixtures in each example and comparative example of the present invention

[0133]

[0134]

[0135] The following conclusions can be drawn from Tables 1 and 2:

[0136] (1) Outstanding ice-melting effect and durability performance: The slow-release ice-melting asphalt mixture based on carbon-strengthened solid waste-based artificial aggregates of the present invention exhibits significant ice-melting effect and durability advantages while meeting the performance indicators of national standards. Through the slow-release mechanism of the snow-melting salt, the ice-melting rate is significantly increased. Compared with the sample in Comparative Example 1, the ice-melting duration of other experimental groups is significantly extended, and it can effectively cope with the complex road conditions in winter in cold regions.

[0137] (2) Superior mechanical properties: The Marshall stability in Examples 1 to 3 is higher than that in the comparative example and is significantly better than that of traditional modified asphalt mixtures. At the same time, the adhesion grade is improved to an excellent level, and the rutting resistance ability is significantly enhanced. These results indicate that the slow-release ice-melting asphalt mixture prepared based on carbon-strengthened solid waste-based artificial aggregates of the present invention has excellent mechanical stability and shear resistance.

[0138] (3) Significantly improved weather resistance: In terms of freeze-thaw resistance and water retention stability, the porosity and immersion residual strength of the examples are significantly improved compared with the comparative examples. The water resistance performance is excellent, and the freeze-thaw loss is significantly reduced. By comparing the experimental results of Comparative Example 3 and Example 3, it shows that the carbonization treatment technology and the microporous structure design of artificial aggregates play an important role in improving the weather resistance of materials.

[0139] (4) Outstanding environmental and economic benefits: By realizing the efficient resource utilization of solid waste-based materials, the present invention not only reduces the accumulation problem of construction solid waste but also reduces the material preparation cost. The combination of carbon strengthening and slow-release snow melting salt technology further reflects the green environmental protection characteristics and economy of the material, providing a sustainable solution for road construction in cold regions.

[0140] In summary, the slow-release ice-melting asphalt mixture based on carbon-strengthened solid waste-based artificial aggregates prepared by the present invention shows excellent performance in mechanical properties, ice-melting effect, and weather resistance, has significant environmental and economic benefits, and is suitable for winter road surface applications in cold regions.

Claims

1. A slow-release ice-melting asphalt mixture based on carbon-reinforced solid waste-based artificial aggregate, characterized by: In parts by weight, it includes 120-140 parts of carbon-reinforced solid waste-based artificial aggregate and 6-8 parts of diatomaceous earth modified asphalt; the carbon-reinforced solid waste-based artificial aggregate includes 105-115 parts of concrete recycled micropowder, 8-15 parts of deicing salt and 7-10 parts of cement; the deicing salt is prepared by mixing salt rock-based sodium chloride and sodium acetate in a weight ratio of 6:

4.

2. The slow-release ice-melting asphalt mixture based on carbon-reinforced solid waste-based artificial aggregate according to claim 1, characterized in that: The diatomite modified asphalt is a composite material based on base asphalt, which is prepared by adding diatomite and uniformly dispersing and high-temperature shear mixing. The diatomite content is 16% to 20% of the base asphalt mass, the softening point is 60 to 75°C, the elongation at 5°C is 50 to 80cm, and the needle penetration at 25°C is 40×0.1mm to 60×0.1mm.

3. The slow-release ice-melting asphalt mixture based on carbon-reinforced solid waste-based artificial aggregate according to claim 1, characterized in that: The Ca / Si molar ratio of the concrete recycled fine powder is 0.8-1.2, the particle size range is 0.075-0.15 mm, and the specific surface area is 0.45-0.65 m2 / g.

4. The slow-release ice-melting asphalt mixture based on carbon-reinforced solid waste-based artificial aggregate according to claim 1, characterized in that: The salt rock-based sodium chloride is obtained by crushing, screening and drying salt rock. The purity of the salt rock-based sodium chloride is above 95%, the particle size range is 0.1-0.3 mm, and the water content is less than 0.5%.

5. The slow-release ice-melting asphalt mixture based on carbon-reinforced solid waste-based artificial aggregate according to claim 1, characterized in that: The sodium acetate is sodium acetate particles with a purity of more than 98% and a particle size of 0.1 to 0.3 mm.

6. The slow-release ice-melting asphalt mixture based on carbon-reinforced solid waste-based artificial aggregate according to claim 1, characterized in that: The cement is ordinary Portland cement with a P·O4 of 2.5, a specific surface area of ​​330 to 360 m2 / kg, a standard consistency water consumption of 25.0% to 27.0%, and an initial setting time of not less than 45 minutes.

7. The method for preparing a slow-release ice-melting asphalt mixture based on carbon-reinforced solid waste-based artificial aggregate according to any one of claims 1 to 6, characterized in that: The specific steps include: A. Preparation of environmentally friendly salt rock-based snow-melting salt: (1) The salt rock raw material is fed into the jaw crusher for preliminary crushing; (2) Using a vibrating screen to screen out salt rock particles with a particle size of 0.1 to 0.3 mm; (3) drying the salt rock particles in an oven at a temperature of 105±5°C for 3-4 hours, and after cooling, obtaining salt rock-based sodium chloride for use; (4) mixing the dried salt rock-based sodium chloride and sodium acetate in a weight ratio of 6:4 to obtain environmentally friendly salt rock-based snow-melting salt; B. Preparation of recycled concrete powder: (1) Use a jaw crusher to crush the waste concrete blocks into particles less than 5 mm in size; (2) Use a vibrating screen to obtain powder with a particle size less than 0.15 mm; (3) Grind the sieved powder into fine powder with a specific surface area of ​​0.45-0.65 m² / g using a grinder and set aside; C. Preparation of carbon-reinforced solid waste-based artificial aggregates: (1) By weight, mix 105-115 parts of recycled concrete powder, 8-15 parts of environmentally friendly salt rock-based snow-melting salt and 7-10 parts of cement and stir evenly; (2) Granulate using a Φ2.5m×10m disc granulator, with the speed controlled at 20-30rpm, the amount of water added being 8%-10% of the total amount of material, the granulation time being 15-20 minutes, and forming aggregate with a particle size of 2-5mm; (3) Place the granulated aggregate in a carbonization device, in a CO2 atmosphere with a concentration of 5% to 10%, control the humidity to 70% to 90%, the temperature to 20 to 25°C, and the carbonization time to 32 to 40 hours for standby use; D. Preparation of diatomite modified asphalt: Based on base asphalt, diatomite is added in an amount of 16% to 20% by mass of the base asphalt, and diatomite-modified asphalt is obtained after uniform dispersion and high-temperature shear mixing; E. Preparation of slow-release ice-melting asphalt mixture: (1) Mixing 120-140 parts of carbon-enhanced solid waste-based artificial aggregate and 6-8 parts of diatomaceous earth-modified asphalt according to the above weight parts; (2) Stir in a mixer at a temperature of 170-180°C for 8-10 minutes at a stirring speed of 50-60 rpm to ensure that the surface of the aggregate is evenly coated with asphalt; (3) After the mixing is completed, the mixture is cooled to obtain a slow-release ice-melting asphalt mixture based on carbon-reinforced solid waste-based artificial aggregate.

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