Skeleton gap type ultrathin overlay mixture and preparation method thereof

Abstract

The invention belongs to the technical field of light building materials, and particularly relates to a skeleton void type ultrathin overlay mixture and a preparation method of the skeleton void type ultrathin overlay mixture. The intercalation dispersion effect of amino-terminated hyperbranched polyamide is utilized to promote the organic modified montmorillonite to be uniformly dispersed in a nanoscale and form a physical barrier network and an intermolecular cross-linked network with asphalt, so that the aging resistance, water damage resistance and high-temperature stability of the asphalt mortar are improved; meanwhile, a multi-stage aggregate grading process is adopted, basalt is taken as a main framework, diabase subjected to composite modification by KH-560 and micro-nano calcium carbonate is taken as a secondary framework for tight embedding and extrusion, and quartz sand and modified micro-nano calcium carbonate are matched for filling gaps, so that double reinforcement of filling and bonding is realized, and excellent anti-skid and noise-reducing performance is realized; the mechanical strength and the structural stability are improved, and the method is suitable for road ultra-thin overlay engineering.

Description

Technical Field

[0001] This invention relates to the field of lightweight building materials technology, and in particular to a skeleton-void type ultra-thin overlay mixture and its preparation method. Background Technology

[0002] With the rapid development of my country's highway transportation industry, traffic volume continues to grow, the proportion of heavy-duty vehicles is increasing, and the public's demands for driving safety and road noise reduction and environmental protection are becoming increasingly stringent. Ultra-thin overlay mixtures, as a core material for improving the quality and efficiency of road maintenance, are widely used in anti-skid wear layers of high-grade highways and urban arterial roads, as well as in the restoration of old road functions. Among them, skeleton-void type overlay mixtures, with their unique large-void interconnected structure, possess the porous structural characteristics of lightweight building materials. They can achieve significant noise reduction effects through sound wave scattering and energy attenuation, and improve the anti-skid performance of the road surface by utilizing the high structural depth formed by exposed coarse aggregates. Simultaneously, they can quickly drain surface water and reduce noise during rainy weather. Water film thickness effectively reduces the risk of water drift, making it a preferred material that balances functionality and environmental protection. However, in practical applications, existing skeleton-type void-type overlay mixtures often need to further increase the porosity in pursuit of better skid resistance and noise reduction capabilities. This inevitably leads to insufficient internal skeleton support and reduced bonding area between aggregates. This not only easily results in mechanical strength problems such as high scattering loss rate and high temperature rutting resistance, but also exacerbates water damage caused by water intrusion due to weak interface bonding and excessive void connectivity, significantly shortening the service life of the pavement. The industry has always faced the inherent contradiction between the high porosity of skeleton-type void-type mixtures and the difficulty in balancing mechanical strength and structural stability. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a skeleton-type ultra-thin overlay mixture and its preparation method. This method modifies asphalt by preparing an amino-terminated hyperbranched polyamide-intercalated organic-modified montmorillonite composite modifier. The intercalation and dispersion effect of the amino-terminated hyperbranched polyamide promotes the uniform dispersion of the organic-modified montmorillonite at the nanoscale, forming a physical barrier network and intermolecular cross-linking network with the asphalt. This enhances the asphalt mastic's anti-aging, water damage resistance, and high-temperature stability. Simultaneously, a multi-stage aggregate gradation process is employed, with basalt as the main skeleton and diabase modified with KH-560 and micro-nano calcium carbonate as the secondary skeleton, creating a tightly interlocked structure. Quartz sand and modified micro-nano calcium carbonate fill the gaps, achieving dual reinforcement of filling and bonding. This results in excellent anti-skid and noise reduction performance while improving mechanical strength and structural stability, making it suitable for ultra-thin road overlay projects.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] In a first aspect, the present invention provides a skeleton-void type ultra-thin overlay mixture, comprising mineral aggregate, asphalt, composite modifier, basalt fiber and polyethylene glycol 400;

[0006] The mineral materials include coarse aggregates and fine aggregate-mineral powder composites; the coarse aggregates include basalt and modified diabase; the fine aggregate-mineral powder composites include quartz sand and modified micro-nano calcium carbonate;

[0007] The composite modifier is obtained by compounding amino-terminated hyperbranched polyamide (HyPerN10) and organically modified montmorillonite (OMMT);

[0008] The modified diabase is obtained by modifying diabase with micro-nano calcium carbonate and silane coupling agent;

[0009] The modified micro / nano calcium carbonate is obtained by surface modification of micro / nano calcium carbonate with stearic acid.

[0010] Further, the mass ratio of the mineral aggregate, asphalt, composite modifier, basalt fiber, and polyethylene glycol 400 is 100:(5.0-6.5):(2.0-3.0):(0.3-0.5):(0.3-0.5); the mass ratio of the coarse aggregate and the fine aggregate-mineral powder compound is (70-80):(18-22); the mass ratio of the quartz sand and modified micro-nano calcium carbonate is 7:3; the mass ratio of the diabase, modified micro-nano calcium carbonate, and silane coupling agent is (23.8-28.6):(1.2-1.4):(0.12-0.14); and the mass ratio of micro-nano calcium carbonate and stearic acid is (7.6-9.2):(0.38-0.46).

[0011] Further, the basalt has a particle size of 5-9.5 mm; the diabase has a particle size of 3-5 mm; the quartz sand has a particle size of 0-3 mm; the micro-nano calcium carbonate has a particle size of 50-200 nm; the silane coupling agent is KH-560; the basalt fiber has a length of 3-5 mm; the asphalt is 70# base asphalt with a softening point of 46-54℃; the HyPerN10 is of type N102 with an amino group number of 7-9 mol / mol; and the OMMT is alkyl quaternary ammonium salt intercalated modified montmorillonite with an interlayer spacing of 1.5-3.5 nm.

[0012] Furthermore, the composition of the ore material, by mass proportion, includes: basalt with a particle size of 5mm-9.5mm accounting for 45%-50% of the total ore mass, modified diabase with a particle size of 3mm-5mm accounting for 25%-30% of the total ore mass, and quartz sand-modified micro-nano calcium carbonate composite with a particle size of 0mm-3mm accounting for 18%-22% of the total ore mass.

[0013] The mineral aggregate blending follows the design of main skeleton support, secondary skeleton auxiliary, and fine aggregate-mineral powder filling. The mineral aggregate blending uses 5-9.5mm basalt as the main skeleton aggregate. Its larger particle size and stronger rigidity allow it to build a basic rigid skeleton of the mixture, which is not easily deformed when subjected to external forces. 3-5mm modified diabase is used as the secondary skeleton aggregate. Its particle size is adapted to the gaps in the basalt. It can be tightly embedded in the gaps of the main skeleton basalt to form a high-density and high-stability interlocking structure with the basalt. While filling the gaps in the main skeleton, it further improves the overall rigidity of the skeleton and makes up for the strength deficiency caused by the high porosity. 0-3mm quartz sand-modified micro-nano calcium carbonate composite, as a fine aggregate-mineral powder composite, can fill the secondary gaps formed by basalt and modified diabase. It not only achieves reasonable filling of voids and improves structural density, but also strengthens the interfacial bonding between various mineral materials by means of the bonding and strengthening effect of modified micro-nano calcium carbonate, thus achieving a dual effect of filling and bonding.

[0014] Furthermore, the sieve aperture passing rate in the gradation process of the ore is controlled as follows: 100% passing rate for 9.5mm sieve, 78%-82% passing rate for 4.75mm sieve, 53%-58% passing rate for 2.36mm sieve, and 3%-5% passing rate for 0.075mm sieve.

[0015] The gradation design ensures the appropriate particle size distribution of basalt, modified diabase, and fine aggregate-mineral powder compound by controlling the passing rate of key sieve holes. This not only guarantees the full interlocking of the main and secondary skeletons to form a stable skeleton structure, but also retains an appropriate amount of interconnected voids to provide a structural basis for noise reduction performance. At the same time, it optimizes the adhesion of asphalt mortar to the surface of the aggregate, so that the asphalt mortar uniformly coats the aggregate, taking into account both bond strength and structural permeability, and synergistically improving anti-slip, noise reduction and mechanical properties.

[0016] Secondly, the present invention provides a method for preparing a skeleton-porous type ultrathin overlay mixture, comprising the following steps:

[0017] S1. Organically modified montmorillonite (OMMT) is added to anhydrous ethanol-water mixed solvent, sonicated, and heated to the first set temperature. Then, amino-terminated hyperbranched polyamide (HyPerN10) is added, reacted, and obtained by vacuum distillation, vacuum drying, grinding, and sieving.

[0018] S2. Basalt and quartz sand are dried to obtain pretreated basalt aggregate and quartz sand; micro-nano calcium carbonate is dried for the first time, stearic acid is added, and it is stirred at high speed. After a second drying, grinding and sieving, modified micro-nano calcium carbonate is obtained; diabase, modified micro-nano calcium carbonate and silane coupling agent are mixed, stirred, and dried for the third time to obtain modified diabase.

[0019] S3. The pretreated basalt, modified diabase, and quartz sand-modified micro-nano calcium carbonate compound are mixed in proportion, and after screening and grading, the mineral material is obtained.

[0020] S4. Heat the graded aggregate to the first set temperature, keep it warm, add composite modifier, basalt fiber and polyethylene glycol 400, dry mix, add molten asphalt, wet mix, control viscosity and discharge temperature to obtain skeleton void type ultra-thin overlay mixture.

[0021] In one feasible implementation, in S1, the mass-to-volume ratio of OMMT, HyPerN10, and anhydrous ethanol-water mixed solvent is (1.6-2.4) kg : (0.4-0.6) kg : (16-24) L; the volume ratio of anhydrous ethanol to water in the anhydrous ethanol-water mixed solvent is 7:3; the ultrasonic power is 300W, and the ultrasonic time is 25-35 min; the first set temperature is 75-85℃; the reaction time is 1.5-2.5 h; the conditions for vacuum distillation are: temperature 75-85℃, pressure -0.07~-0.09 MPa; the vacuum drying temperature is 55-65℃, and the vacuum drying time is 3.5-4.5 h; the sieve mesh size is 2500-3000 mesh.

[0022] HyPerN10 possesses a typical hyperbranched molecular structure with numerous active terminal amino groups. Its low steric hindrance and excellent dispersibility allow it to interact with polar groups on the surface of OMMT sheets through molecular polarity, penetrating into the interlaminar spaces of OMMT via intercalation. OMMT naturally exhibits a layered stacked structure, prone to agglomeration due to van der Waals forces. The insertion of HyPerN10 breaks this agglomeration and, through the spatial support of its hyperbranched structure, widens the interlaminar spacing, ensuring uniform nanoscale dispersion of OMMT within the system and preventing modification failure caused by agglomeration. Furthermore, the terminal amino groups in the HyPerN10 molecule provide a foundation for subsequent reactions with polar components in asphalt, offering structural support for the formation of a physical barrier network in the asphalt mastic and strengthening intermolecular bonds, thus contributing to improved anti-aging, water damage resistance, and adhesion properties.

[0023] In one feasible implementation, in step S2, the drying temperature is 100-110℃, and the drying time is 1.5-2.5h; the first drying temperature is 100-110℃, and the first drying time is 0.5-1.5h; the high-speed stirring conditions are: temperature 80-90℃, rotation speed 1400-1600r / min, and time 25-35min; the second drying temperature is 100-110℃, and the second drying time is 0.5-1.5h; the grinding and sieving mesh size is 180-220 mesh; the stirring conditions are: temperature 75-85℃, rotation speed 1400-1600r / min, and time 25-35min; the third drying temperature is 100-110℃, and the third drying time is 0.5-1.5h.

[0024] Drying the main aggregate basalt and fine aggregate quartz sand completely removes the moisture adsorbed inside and on the surface, preventing the formation of a water film at the interface between the aggregate and asphalt during subsequent mixing. This prevents a decrease in the bond strength between the asphalt and aggregate, creating conditions for efficient bonding. After surface modification with stearic acid, the hydrophobic groups of stearic acid cover the surface of micro- and nano-calcium carbonate, reducing its hydrophilicity, improving its compatibility with hydrophobic asphalt, reducing the aggregation of micro- and nano-calcium carbonate, and enhancing its dispersibility in the gaps between the asphalt and aggregate. This provides support for subsequent gap filling and strengthening of structural density. In the preparation of secondary skeleton aggregate modified diabase, KH-560 silane coupling agent plays a key bridging role. The alkoxy group at one end can undergo hydrolysis and condensation reaction with the hydroxyl groups on the surface of diabase, while the organic group at the other end can be compatible with asphalt and modified micro-nano calcium carbonate. At the same time, the modified micro-nano calcium carbonate can adhere to the surface of diabase, forming a rough and porous structure on the surface of diabase. This significantly increases the contact area with asphalt mortar, strengthens the interfacial bond strength between basalt and diabase, and improves the surface friction coefficient of diabase, optimizing its interlocking compatibility with basalt. This gives the mixture both anti-skid performance and structural stability.

[0025] In one feasible implementation, in step S4, the first set temperature is 145-155℃; the heat preservation time is 8-12 min; the dry mixing speed is 280-320 r / min, and the dry mixing time is 40-50 s; the melting temperature of the asphalt is 135-145℃; the wet mixing speed is 230-270 r / min, and the wet mixing time is 40-70 s; the viscosity is controlled at 3200-3800 mPa·s at 145℃; and the discharge temperature is 135-155℃.

[0026] Preheating the aggregates ensures that the temperature of basalt, modified diabase, and other aggregates matches that of the molten asphalt, preventing rapid cooling and decreased fluidity of the asphalt upon contact with the aggregates due to temperature differences. This avoids problems such as uneven bonding and insufficient dispersion of the modifier, ensuring efficient bonding between the asphalt and the aggregates. During the dry mixing stage, the added composite modifier, basalt fiber, and polyethylene glycol 400 are evenly dispersed on the surface of the aggregates. The basalt fiber can penetrate the gaps between the basalt and modified diabase, forming a support network that enhances the toughness and crack resistance of the mixture and inhibits structural deformation. Polyethylene glycol 400, as a compatibility modifier, improves the interfacial compatibility between the asphalt, aggregates, and composite modifiers, reducing interfacial defects and laying the foundation for subsequent wet mixing.

[0027] During the wet mixing stage, the molten 70# base asphalt comes into full contact with the aggregates and various modified components. Precise control of temperature and viscosity allows the asphalt to maintain suitable fluidity and adhesion, promoting a full reaction between the HyPerN10-OMMT composite modifier and the asphalt. The terminal amino groups of HyPerN10 undergo physical adsorption and chemical cross-linking with the polar components of the asphalt, forming an intermolecular cross-linking network. The OMMT nanosheets form a continuous physical barrier network. At the same time, the asphalt uniformly coats the surface of the aggregates and fills the gaps. Finally, through the synergistic effect of the components, a structurally stable, skeleton-type, porous, ultra-thin overlay mixture with excellent anti-skid and noise reduction properties and mechanical strength is formed.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] This method modifies asphalt by preparing an amino-terminated hyperbranched polyamide (HyPerN10) intercalated organic modified montmorillonite (OMMT) composite modifier. Combined with a multi-grade aggregate gradation process, a skeleton-porosity ultrathin overlay mixture is obtained, achieving excellent anti-skid and noise reduction performance while improving the mechanical strength and structural stability of the mixture. HyPerN10 intercalates into the interlayer gaps of OMMT, breaking up the agglomeration of the layers and widening the interlayer spacing, promoting the uniform dispersion of OMMT in the asphalt at the nanoscale, forming a continuous physical barrier network. This effectively delays the intrusion of oxygen, ultraviolet rays, and moisture, thereby improving the asphalt mastic's anti-aging and water damage resistance. Simultaneously, the amino-terminated groups of HyPerN10 can undergo physical adsorption and chemical cross-linking with polar components in the asphalt, forming an intermolecular cross-linking network, improving the asphalt's adhesion and high-temperature stability. In addition, OMMT sheets, with their nanoscale effects and surface active sites, bind tightly to the aggregate surface through coordination, hydrogen bonding and other interactions, forming a dense and tough transition layer at the aggregate-asphalt interface, providing sufficient bonding support for the ultra-thin overlay structure.

[0030] The multi-stage aggregate gradation process tightly interlocks the primary skeleton basalt with the secondary skeleton diabase, forming a high-density, high-stability skeleton structure. The interconnected internal void structure reduces noise, while the dense interlocking structure compensates for the strength loss caused by the high porosity. Specifically, the diabase is modified with KH-560 and micro / nano calcium carbonate, resulting in a rough, porous surface structure that increases the contact area with asphalt mortar, strengthens the interfacial bond between the skeletons, and improves the surface friction coefficient of the aggregates. This, combined with the rough surface formed by the two-stage skeleton interlocking, enhances the anti-skid performance of the mixture. Furthermore, the use of quartz sand and micro / nano calcium carbonate to fill the gaps further achieves dual reinforcement of filling and bonding, resolving the inherent contradiction between high porosity and mechanical strength and structural stability in skeleton-type mixtures. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the preparation process of a skeleton-void type ultrathin cover mixture according to the present invention. Detailed Implementation

[0032] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the application will be further described in detail below with reference to embodiments. However, this should not be construed as limiting the scope of this application to the following examples. All other embodiments obtained by those skilled in the art without creative effort without departing from the above-described methodological spirit of this application are within the scope of protection of this application.

[0033] The singular forms “for,” “or,” “a,” “any,” and “described” used in this application are intended to include the plural forms unless the context clearly indicates otherwise. Furthermore, the terms “first” and “second” are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] Example 1

[0035] like Figure 1 As shown, a method for preparing a skeleton-porous ultrathin overlay mixture includes the following steps:

[0036] S1. 2 kg of OMMT with a layer spacing of 2 nm was added to 20 L of anhydrous ethanol-water mixed solvent, wherein the volume ratio of anhydrous ethanol to water in the anhydrous ethanol-water mixed solvent was 7:3. The mixture was ultrasonically dispersed at 300 W for 30 min. Then, the system was heated to 80 °C, and 0.5 kg of HyPerN10 with an amino group of 8 mol / mol was added to the system. The temperature was kept constant at 80 °C and the mixture was stirred continuously at 500 r / min for 2 h. After stirring, the solvent was recovered by vacuum distillation at 80 °C and -0.08 MPa. The product was then placed in a vacuum drying environment at 60 °C for 4 h. The dried product was then ground. Anhydrous ethanol, accounting for 1.5% of the total mass of the composite modifier, was added as a grinding aid during grinding. After grinding, the product was sieved using a 3000 mesh standard sieve to obtain the composite modifier.

[0037] S2. Mineral Pretreatment: 48 kg of basalt aggregate with a particle size of 5-9.5 mm and 15.4 kg of quartz sand with a particle size of 0-3 mm are dried at 105℃ for 2 hours to obtain pretreated basalt and quartz sand; 6.6 kg of micro-nano calcium carbonate with a particle size of 100 nm is dried at 105℃ for 1 hour, cooled to room temperature, and then 0.42 kg of stearic acid is added. The two are then put into a high-speed mixer and stirred at 1500 r / min at 85℃. After mixing for 30 minutes to complete surface modification, continue drying at 105℃ for 1 hour. After grinding, pass through a 200-mesh standard sieve to obtain modified micro-nano calcium carbonate. Add 1.3 kg of modified micro-nano calcium carbonate and 0.13 kg of KH-560 silane coupling agent to 30 kg of diabase with a particle size of 3-5 mm. Stir at high speed for 30 minutes at 80℃ and 1500 r / min. Then dry at 105℃ for 1 hour to complete solidification. Cool to room temperature to obtain modified diabase.

[0038] S3. The pretreated ore was blended according to the gradation design mass ratio. The proportions of each component were as follows: 48% pretreated basalt aggregate (5-9.5mm), 30% modified diabase (3-5mm), and 22% quartz sand-modified micro-nano calcium carbonate blend (0-3mm). The mass ratio of quartz sand to modified micro-nano calcium carbonate was 7:3. The blended ore was then graded. The passing rates of the key sieves were as follows: 97% for 9.5mm sieve, 80% for 4.75mm sieve, 55% for 2.36mm sieve, and 4% for 0.075mm sieve. The resulting gradation is shown in Table 1.

[0039] Table 1. Mineral aggregate gradation data in Example 1

[0040]

[0041] S4. Heat 100kg of graded aggregate to 150℃ and maintain the temperature for 10 minutes. Then, put it into a forced mixing pot. Add 2.5kg of composite modifier, 0.4kg of basalt fiber with a length of 3-5mm and 0.4kg of polyethylene glycol 400 to the mixing pot. Dry mix at 300r / min for 45s. Heat 5.75kg of 70# base asphalt to 140℃ and melt it completely. Add it to the mixing pot and wet mix at 250r / min for 55s. During the mixing process, control the system temperature at 145℃. Use a portable Brookfield viscometer with an S64 rotor to test the viscosity at 50r / min. Ensure that the system viscosity at 145℃ is 3500mPa·s. After wet mixing, control the total mixing time to 125s and control the material discharge temperature to 145℃ to obtain a skeleton-void type ultra-thin overlay mixture.

[0042] Example 2

[0043] like Figure 1 As shown, a method for preparing a skeleton-porous ultrathin overlay mixture includes the following steps:

[0044] S1. 1.6 kg of OMMT with an interlayer spacing of 1.5 nm was added to 16 L of anhydrous ethanol-water mixed solvent, wherein the volume ratio of anhydrous ethanol to water in the anhydrous ethanol-water mixed solvent was 7:3. The mixture was ultrasonically dispersed at 300 W for 25 min. Then, the system was heated to 75 °C, and 0.4 kg of HyPerN10 with an amino group of 7 mol / mol was added to the system. The temperature was maintained at 75 °C and the mixture was stirred continuously at 500 r / min for 1.5 h. After stirring, the solvent was recovered by vacuum distillation at 75 °C and -0.07 MPa. The product was then vacuum dried at 55 °C for 3.5 h. The dried product was then ground, and anhydrous ethanol of 1.5% of the total mass of the composite modifier was added as a grinding aid during grinding. After grinding, the product was sieved using a 2500 mesh standard sieve to obtain the composite modifier.

[0045] S2. Mineral Pretreatment: 49 kg of basalt aggregate with a particle size of 5-9.5 mm and 15.4 kg of quartz sand with a particle size of 0-3 mm are dried at 100℃ for 1.5 h to obtain pretreated basalt and quartz sand; 6.6 kg of micro-nano calcium carbonate with a particle size of 50 nm is dried at 100℃ for 0.5 h, cooled to room temperature, and 0.38 kg of stearic acid is added. The two are then put into a high-speed mixer and stirred at 1400 r / min at 80℃. After surface modification for 25 minutes, the mixture was dried at 100℃ for 0.5 hours. After grinding, it was passed through a 180-mesh standard sieve to obtain modified micro-nano calcium carbonate. 1.2 kg of modified micro-nano calcium carbonate and 0.12 kg of KH-560 silane coupling agent were added to 29 kg of diabase with a particle size of 3-5 mm. The mixture was stirred at high speed at 75℃ and 1400 r / min for 25 minutes, and then dried at 100℃ for 0.5 hours to complete the curing. After cooling to room temperature, modified diabase was obtained.

[0046] S3. The pretreated ore was blended according to the designed gradation mass ratio. The proportions of each component were as follows: 49% pretreated basalt aggregate (5-9.5mm), 29% modified diabase (3-5mm), and 22% quartz sand-modified micro-nano calcium carbonate blend (0-3mm). The mass ratio of quartz sand to modified micro-nano calcium carbonate was 7:3. The blended ore was then subjected to gradation testing. The passing rates of the key sieves were as follows: 98% for 9.5mm sieve, 82% for 4.75mm sieve, 57% for 2.36mm sieve, and 5% for 0.075mm sieve. The resulting gradation is shown in Table 2.

[0047] Table 2 Mineral gradation data in Example 2

[0048]

[0049] S4. Heat 100kg of aggregate to 145℃ and maintain the temperature for 8 minutes. Then, put it into a forced mixing pot, add composite modifier, 0.3kg of basalt fiber with a length of 3-5mm and 0.3kg of polyethylene glycol 400 to the mixing pot, and dry mix at 280r / min for 40s. Heat 5.0kg of 70# base asphalt to 135℃ and melt it completely, then add it to the mixing pot and wet mix at 230r / min for 40s. During the mixing process, control the system temperature at 135℃. Use a portable Brookfield viscometer with an S64 rotor to detect the viscosity at 50r / min, and ensure that the system viscosity at 135℃ is 3200mPa·s. After wet mixing, control the total mixing time to 110s and control the material discharge temperature to 135℃ to obtain a skeleton-void type ultra-thin overlay mixture.

[0050] Example 3

[0051] like Figure 1 As shown, a method for preparing a skeleton-porous ultrathin overlay mixture includes the following steps:

[0052] S1. 2.4 kg of OMMT with an interlayer spacing of 3.5 nm was added to 24 L of anhydrous ethanol-water mixed solvent, wherein the volume ratio of anhydrous ethanol to water in the anhydrous ethanol-water mixed solvent was 7:3. The mixture was ultrasonically dispersed at 300 W for 35 min. Then the system was heated to 85 °C, and 0.6 kg of HyPerN10 with an amino group of 9 mol / mol was added to the system. The temperature was maintained at 85 °C and the mixture was stirred continuously at 500 r / min for 2.5 h. After stirring, the solvent was recovered by vacuum distillation at 85 °C and -0.09 MPa. The product was then vacuum dried at 65 °C for 4.5 h. The dried product was then ground, and anhydrous ethanol of 1.5% of the total mass of the composite modifier was added as a grinding aid during grinding. After grinding, the product was sieved using a 2800 mesh standard sieve to obtain the composite modifier.

[0053] S2. Mineral Pretreatment: 50 kg of basalt aggregate with a particle size of 5-9.5 mm and 14 kg of quartz sand with a particle size of 0-3 mm are dried at 110℃ for 2.5 h to obtain pretreated basalt and quartz sand; 6.0 kg of micro / nano calcium carbonate with a particle size of 200 nm is dried at 110℃ for 1.5 h, cooled to room temperature, and then 0.46 kg of stearic acid is added. Both are then put into a high-speed mixer and mixed at 1600 r / min at 90℃. After stirring for 30 minutes to complete surface modification, continue drying at 105℃ for 1 hour. After grinding, pass through a 200-mesh standard sieve to obtain modified micro-nano calcium carbonate. Add 1.4 kg of modified micro-nano calcium carbonate and 0.14 kg of KH-560 silane coupling agent to 30 kg of diabase with a particle size of 3-5 mm. Stir at high speed at 85℃ and 1500 r / min for 30 minutes, then dry at 105℃ for 1 hour to complete solidification. Cool to room temperature to obtain modified diabase.

[0054] S3. The pretreated ore was blended according to the gradation design mass ratio. The proportions of each component were as follows: 50% pretreated basalt aggregate (5-9.5mm), 30% modified diabase (3-5mm), and 20% quartz sand-modified micro-nano calcium carbonate blend (0-3mm). The mass ratio of quartz sand to modified micro-nano calcium carbonate was 7:3. The blended ore was then subjected to gradation testing. The passing rates of the key sieves were controlled as follows: 95% for 9.5mm sieve, 78% for 4.75mm sieve, 54% for 2.36mm sieve, and 3% for 0.075mm sieve. The resulting gradation is shown in Table 3.

[0055] Table 3. Mineral aggregate gradation data in Example 3

[0056]

[0057] S4. Heat 100kg of graded aggregate to 150℃ and maintain the temperature for 10 minutes. Then, put it into a forced mixing pot. Add 2.0kg of composite modifier, 0.5kg of basalt fiber with a length of 3-5mm and 0.5kg of polyethylene glycol 400 to the mixing pot. Dry mix at 320r / min for 50s. Heat 6.5kg of 70# base asphalt to 145℃ and melt it completely. Add it to the mixing pot and wet mix at 270r / min for 70s. During the mixing process, control the system temperature at 155℃. Use a portable Brookfield viscometer with an S64 rotor to test the viscosity at 50r / min. Ensure that the system viscosity at 155℃ is 3800mPa·s. After wet mixing, control the total mixing time to 140s and control the material discharge temperature to 155℃ to obtain a skeleton-void type ultra-thin overlay mixture.

[0058] Comparative Example 1

[0059] A method for preparing a skeleton-void type ultrathin overlay mixture differs from Example 1 in that a composite modifier is not prepared in step S1, while the remaining steps and parameters are the same.

[0060] Comparative Example 2

[0061] A method for preparing a skeleton-void type ultrathin overlay mixture differs from Example 1 in that HyPerN10 is not added in step S1, i.e. there is no HyPerN10 intercalation modification, only a single OMMT is used, and the remaining steps and parameters are the same.

[0062] Comparative Example 3

[0063] A method for preparing a skeleton-void type ultrathin overlay mixture differs from Example 1 in that step S2 does not involve KH-560 and modified micro-nano calcium carbonate composite modification of diabase; instead, unmodified diabase is used directly. The remaining steps and parameters are the same.

[0064] Comparative Example 4

[0065] A method for preparing a skeleton-porous ultrathin overlay mixture differs from Example 1 in that the mineral compounding ratio in step S3 is adjusted to a conventional ratio. Specifically, the proportions of each component by mass are: 25% 5-9.5mm basalt, 20% 3-5mm diabase, and 55% 0-3mm quartz sand-modified micro-nano calcium carbonate composite. The corresponding key sieve aperture passing rates are simultaneously adjusted to: 100% for 9.5mm sieve, 88% for 4.75mm sieve, 68% for 2.36mm sieve, and 7% for 0.075mm sieve. The remaining steps and parameters are the same.

[0066] Performance testing:

[0067] Anti-slip performance test: A BM-3 pendulum friction coefficient tester was used, with the test temperature controlled at 25℃ and the pendulum impact number 3 times per test point. The mixture was prepared into standard specimens of 300mm×300mm×50mm. After standard curing for 7 days, 5 test points were evenly selected on the specimen surface (avoiding the edge within 50mm). Outliers were removed, and the average value was taken as the pendulum value (BPN). Texture depth was determined using a manual sand-spreading method. 25g of standard sand with a particle size of 0.15-0.3mm was selected. Since the bulk density of this standard sand is approximately 1g / cm³, the standard sand volume V was taken as 25mL. Similarly, 5 corresponding test points were selected, and the sand was evenly spread with a pusher plate until there were no obvious gaps. The diameter was measured 3 times in different directions (angle ≥120°) on the circular sand surface. Outliers were removed, and the average value was taken as the average diameter D (unit: mm). The texture depth T was then calculated using a standard formula. d =πD24000V, where π is 3.1416. The average value of the five measuring points is taken as the final construction depth. The higher the values ​​of the two indicators, the better the anti-skid performance of the mixture.

[0068] Noise reduction performance test: An HS5670 reverberation chamber sound absorption coefficient measuring instrument was used. The reverberation chamber volume was 20m³, and the test environment temperature was 25℃ and the relative humidity was 50%. The mixture was made into 1000mm×1000mm×50mm specimens. After curing for 7 days, the surface dust was removed, and the specimens were placed stably in the designated position in the reverberation chamber and fixed. The reverberation time of the empty chamber and after placing the specimens were tested. Each frequency point was tested 3 times. The sound absorption coefficient α was calculated using the formula: α=1-(V / cA)·ln(T0 / T), where α is the sound absorption coefficient, V is the reverberation chamber volume (m³), c is the speed of sound in air (m / s, taken as 346m / s at 25℃), A is the surface area of ​​the specimen (m²), T0 is the reverberation time of the empty chamber, and T is the reverberation time after placing the specimens. The average value was taken after calculation. A sound absorption coefficient ≥0.3 is the qualified standard for the noise reduction performance of the skeleton void type mixture.

[0069] Mechanical strength testing: Mechanical strength was evaluated using both Marshall stability and splitting tensile strength. Marshall stability was tested using a DTS-30 Marshall stability tester. Standard Marshall specimens with a diameter of 101.6±0.2 mm and a height of 63.5±1.3 mm were prepared from the mixture. After curing for 7 days, the specimens were placed in a 60℃ constant temperature water bath for 30 minutes. Immediately after removal, the specimens were placed at the center of the instrument's indenter and loaded uniformly at a rate of 50 mm / min until failure. The Marshall stability (kN) was the maximum failure load directly read by the instrument, and the flow value (mm) was recorded simultaneously. The splitting strength test was conducted using a WDW-100 universal testing machine. The specimen specifications were the same as those of the Marshall specimen. After curing for 7 days, the specimen was placed in a 25℃ environment for 2 hours. After centering, it was loaded at a rate of 1 mm / min until splitting failure. The maximum failure load P (N) was recorded. The splitting strength σ = πdh²P was calculated using the formula, where d is the specimen diameter (mm), h is the specimen height (mm), and π is taken as 3.1416. The average value was taken after substituting the parameters into the calculation.

[0070] Water damage resistance test: Water damage resistance was evaluated using the freeze-thaw splitting strength ratio (TSR). The mixture was prepared into standard cylindrical specimens with a diameter of 101.6 mm and a height of 63.5 mm. After curing for 7 days, the specimens were divided into a non-freeze-thaw group and a freeze-thaw group, with 3 specimens in each group. The non-freeze-thaw group was placed in a 25℃ environment for 2 hours, and the splitting strength R1 was measured using a universal testing machine at a rate of 1 mm / min. The data was calculated using the splitting strength formula mentioned above. The freeze-thaw group was first frozen in a -18℃ freezer for 16 hours, then immediately immersed in a 25℃ constant temperature water bath for 24 hours. After drying the surface moisture, the splitting strength R2 was measured using the same method. The calculation formula was: Freeze-thaw splitting strength ratio TSR1 = (R2 / R1) × 100%, and the average value was taken.

[0071] Anti-aging performance test: Anti-aging performance was evaluated by the splitting strength ratio after short-term aging, using the Rotary Thin Film Oven Aging Method (RTFOT). An appropriate amount of the mixture was placed in the RTFOT oven, and the aging temperature was set to 163℃, the rotation speed to 15 r / min, and the aging time to 75 min. After aging, the mixture was cooled to room temperature, and standard specimens with a diameter of 101.6 mm and a height of 63.5 mm were prepared. Simultaneously, unaged specimens of the same specifications were prepared. Both groups were cured for 7 days under standard conditions. After being placed in a 25℃ environment for 2 hours, the splitting strength R3 after aging and the unaged splitting strength R4 were measured at a rate of 1 mm / min. The strength ratio TSR2 was calculated using the formula TSR2 = (R3 / R1) × 100%, and the average value was taken.

[0072] The test results are shown in Table 4.

[0073] Table 4 Performance test results of the skeleton-porosity ultrathin overlay mixtures prepared in Examples 1-3 and Comparative Examples 1-4

[0074]

[0075] As shown in Table 4, the pendulum value, structural depth, sound absorption coefficient, Marshall stability, and splitting strength of the skeleton-void type ultrathin cover mixtures prepared in Examples 1-3 are all higher than those of Comparative Examples 1-4. Furthermore, the freeze-thaw and anti-aging splitting strength ratios are also higher than those of Comparative Examples 1-4. This indicates that the skeleton-void type ultrathin cover mixtures prepared in Examples 1-3 have better anti-slip, noise reduction, mechanical strength, water damage resistance, and anti-aging properties than those of Comparative Examples 1-4.

[0076] Comparative Example 1, lacking the HyPerN10-OMMT composite modifier and using only 70# base asphalt, lacked the dual modification effect of the composite modifier. Due to the absence of the intercalation synergy between HyPerN10 and OMMT, a nanoscale physical barrier network could not be formed, allowing oxygen, ultraviolet radiation, and moisture to easily penetrate, resulting in a significant decrease in anti-aging and water damage performance. Simultaneously, the lack of cross-linking between terminal amino groups and the polar components of asphalt, as well as the interfacial bonding strengthening effect of OMMT, resulted in insufficient asphalt adhesiveness and high-temperature stability, leading to reduced mechanical strength. Furthermore, the weak interfacial bond between asphalt and aggregate further caused a fundamental deterioration in anti-skid and noise reduction performance. This fully demonstrates that composite modifiers are the core foundation for improving the overall performance of mixtures.

[0077] Comparative Example 2 used only OMMT modification without adding HyPerN10, which failed to leverage the synergistic intercalation effect of the two. Due to the lack of the terminal amino group effect of HyPerN10, the OMMT sheets were difficult to be effectively intercalated and dispersed, and were prone to agglomeration. They could not form a continuous physical barrier network in the asphalt, and the lack of intermolecular cross-linking network construction resulted in limited improvement in the adhesion and anti-aging properties of the asphalt mastic. At the same time, the agglomeration of OMMT weakened the interfacial interaction with the aggregate surface, reduced mechanical strength and water damage resistance, and decreased anti-skid and noise reduction properties due to insufficient asphalt modification. This indicates that HyPerN10 plays a key role in intercalation dispersion, cross-linking enhancement, and synergistic modification, and that OMMT alone cannot achieve the optimal effect of composite modification.

[0078] Comparative Example 3 did not involve the composite modification of diabase with KH-560 and modified micro / nano calcium carbonate, resulting in insufficient interfacial bonding between the aggregate and asphalt. The unmodified diabase had a smooth surface and few active sites, limiting its contact area with the asphalt mastic and leading to low interfacial bonding strength. This prevented the formation of a stable multi-level interlocking framework with the basalt, resulting in decreased mechanical strength. Simultaneously, the low surface friction coefficient of the diabase prevented the formation of a rough surface through multi-level interlocking, weakening its anti-skid performance. Furthermore, the lack of modified micro / nano calcium carbonate filling and the coupling effect of KH-560 resulted in insufficient interfacial compatibility between the aggregate and asphalt, reducing water damage resistance and structural stability. This highlights the strengthening effect of diabase composite modification on interfacial bonding, anti-skid performance, and framework stability.

[0079] Comparative Example 4 uses a conventional continuous gradation. After adjusting the aggregate blending ratio, the multi-stage interlocking structure of basalt and modified diabase is missing. In the conventional continuous gradation, the proportion of large-diameter basalt and diabase is significantly reduced, while the blending ratio of fine aggregate and mineral powder increases to 55%. This fails to form a high-density, high-stability skeleton structure, and the internal porosity is insufficient. It cannot achieve excellent noise reduction through interconnected voids, nor can it form a rough surface to enhance anti-skid performance. At the same time, without the support of the interlocking skeleton, the excessive filling of fine aggregate leads to insufficient overall structural toughness of the mixture, and the mechanical strength and water damage resistance are significantly reduced. This fully demonstrates that multi-stage aggregate interlocking gradation is the key to solving the contradiction between high porosity and mechanical strength and structural stability in skeleton-type mixtures, and it is also the core design for improving anti-skid and noise reduction performance.

[0080] Comparative Examples 1-4, due to the lack of the synergistic effect of the composite modification of HyPerN10 and OMMT, the modification treatment of diabase, and the multi-stage aggregate interlocking structure, resulted in insufficient modification of the asphalt mastic, weak aggregate interface bonding, and lack of skeleton structure stability. These factors collectively manifested as varying degrees of deterioration in anti-skid properties, noise reduction, mechanical strength, water damage resistance, and aging resistance.

[0081] The above results demonstrate and describe the basic principles and main features of this application, as well as its advantages.

[0082] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A skeleton-porous type ultrathin overlay compound, characterized in that, Including minerals, asphalt, composite modifiers, basalt fiber, and polyethylene glycol 400; The mineral materials include coarse aggregates and fine aggregate-mineral powder composites; the coarse aggregates include basalt and modified diabase; the fine aggregate-mineral powder composites include quartz sand and modified micro-nano calcium carbonate; The composite modifier is obtained by compounding amino-terminated hyperbranched polyamide with organically modified montmorillonite; The modified diabase is obtained by modifying diabase with micro-nano calcium carbonate and silane coupling agent; The modified micro / nano calcium carbonate is obtained by surface modification of micro / nano calcium carbonate with stearic acid.

2. The skeleton-porous type ultra-thin overlay mixture according to claim 1, characterized in that, The mass ratio of the mineral aggregate, asphalt, composite modifier, basalt fiber, and polyethylene glycol 400 is 100:(5.0-6.5):(2.0-3.0):(0.3-0.5):(0.3-0.5); the mass ratio of the coarse aggregate and the fine aggregate-mineral powder compound is (70-80):(18-22); the mass ratio of the quartz sand and modified micro-nano calcium carbonate is 7:3; the mass ratio of the diabase, modified micro-nano calcium carbonate, and silane coupling agent is (23.8-28.6):(1.2-1.4):(0.12-0.14); and the mass ratio of micro-nano calcium carbonate and stearic acid is (7.6-9.2):(0.38-0.46).

3. The skeleton-porous type ultra-thin overlay mixture according to claim 1, characterized in that, The basalt has a particle size of 5-9.5 mm; the diabase has a particle size of 3-5 mm; the quartz sand has a particle size of 0-3 mm; the micro-nano calcium carbonate has a particle size of 50-200 nm; the silane coupling agent is KH-560; the basalt fiber has a length of 3-5 mm; the asphalt is 70# base asphalt with a softening point of 46-54℃; the terminal amino hyperbranched polyamide is of type N102 with an amino number of 7-9 mol / mol; the organic modified montmorillonite is alkyl quaternary ammonium salt intercalated modified montmorillonite with an interlayer spacing of 1.5-3.5 nm.

4. The skeleton-porous type ultra-thin cover mixture according to claim 1, characterized in that, The composition of the ore by mass proportion includes: basalt with a particle size of 5mm-9.5mm accounting for 45%-50% of the total ore mass, modified diabase with a particle size of 3mm-5mm accounting for 25%-30% of the total ore mass, and quartz sand-modified micro-nano calcium carbonate composite with a particle size of 0mm-3mm accounting for 18%-22% of the total ore mass.

5. The skeleton-porous type ultra-thin overlay mixture according to claim 4, characterized in that, The gradation process of the ore is controlled as follows: 100% pass rate for 9.5mm sieve, 78%-82% pass rate for 4.75mm sieve, 53%-58% pass rate for 2.36mm sieve, and 3%-5% pass rate for 0.075mm sieve.

6. A method for preparing a skeleton-void type ultrathin overlay mixture as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Add organic modified montmorillonite to anhydrous ethanol-water mixed solvent, sonicate, raise to the first set temperature, add terminal amino hyperbranched polyamide, react, and obtain the composite modifier by vacuum distillation, vacuum drying, grinding and sieving. S2. Basalt and quartz sand are dried to obtain pretreated basalt aggregate and quartz sand; micro-nano calcium carbonate is dried for the first time, stearic acid is added, and it is stirred at high speed. After a second drying, grinding and sieving, modified micro-nano calcium carbonate is obtained. The modified diabase, modified micro-nano calcium carbonate, and silane coupling agent were mixed, stirred, and dried for a third time to obtain the modified diabase. S3. The pretreated basalt, modified diabase, and quartz sand-modified micro-nano calcium carbonate compound are mixed in proportion, and after screening and grading, the mineral material is obtained. S4. Heat the graded aggregate to the first set temperature, keep it warm, add composite modifier, basalt fiber and polyethylene glycol 400, dry mix, add molten asphalt, wet mix, control viscosity and discharge temperature to obtain skeleton void type ultra-thin overlay mixture.

7. The method for preparing a skeleton-porous ultrathin overlay mixture according to claim 6, characterized in that, In step S1, the mass-to-volume ratio of the organically modified montmorillonite, the amino-terminated hyperbranched polyamide, and the anhydrous ethanol-water mixed solvent is (1.6-2.4) kg : (0.4-0.6) kg : (16-24) L; the volume ratio of anhydrous ethanol to water in the anhydrous ethanol-water mixed solvent is 7:3; the ultrasonic power is 300W, and the ultrasonic time is 25-35 min; the first set temperature is 75-85℃; the reaction time is 1.5-2.5 h; the conditions for vacuum distillation are: temperature 75-85℃, pressure -0.07~-0.09 MPa; the vacuum drying temperature is 55-65℃, and the vacuum drying time is 3.5-4.5 h; the sieve mesh size is 2500-3000 mesh.

8. The method for preparing a skeleton-porous ultrathin overlay mixture according to claim 6, characterized in that, In step S2, the drying temperature is 100-110℃ and the drying time is 1.5-2.5h; the temperature of the first drying is 100-110℃ and the drying time is 0.5-1.5h; the conditions for high-speed stirring are: temperature 80-90℃, rotation speed 1400-1600r / min, and time 25-35min.

9. The method for preparing a skeleton-porous ultrathin overlay mixture according to claim 6, characterized in that, In step S2, the temperature of the second drying is 100-110℃, and the drying time is 0.5-1.5h; the mesh size of the grinding and sieving is 180-220 mesh; the stirring conditions are: temperature 75-85℃, rotation speed 1400-1600r / min, and time 25-35min; the temperature of the third drying is 100-110℃, and the drying time is 0.5-1.5h.

10. The method for preparing a skeleton-porous ultrathin overlay mixture according to claim 6, characterized in that, In step S4, the first set temperature is 145-155℃; the heat preservation time is 8-12 min; the dry mixing speed is 280-320 r / min, and the dry mixing time is 40-50 s; the melting temperature of the asphalt is 135-145℃; the wet mixing speed is 230-270 r / min, and the wet mixing time is 40-70 s; the viscosity is controlled at 3200-3800 mPa·s at 145℃; and the discharge temperature is 135-155℃.

Images