Substrate joint filling material for cement pavement white-to-black overlay, preparation method and application

Abstract

The invention discloses a base joint filling material for a white-to-black overlay of a cement pavement, a preparation method and application, the base joint filling material comprises, by mass, 25-35 parts of an asphalt material, 12-15 parts of mineral powder, 25-40 parts of aggregate and 15-30 parts of elastic particles, the particle size of the mineral powder is less than 0.075 mm, the particle size of the aggregate is 1-3 mm or 3-5 mm, and the particle size of the elastic particles is 1-3 mm or 3-5 mm. According to the method, the aggregate of the joint filling material is innovatively classified on the basis of the broken edge joint defect size, high filling compactness and good flexibility are guaranteed by matching fine aggregate with small-particle-size elastic particles for small-size joints, and effective support is provided by matching coarse aggregate with large-particle-size elastic particles for large-size joints; and accurate matching of material performance and engineering requirements is realized.

Description

Technical Field

[0001] This invention belongs to the field of road engineering technology, specifically relating to a base filler material, preparation method and application for the overlay of cement pavement in the process of converting white pavement to black pavement. Background Technology

[0002] Many of the early cement concrete pavements built in my country are now entering their repair or renovation phase. To improve driving comfort, reduce noise, and enhance pavement performance, "white-to-black" (i.e., adding an asphalt concrete surface layer to the old cement concrete pavement) has become one of the main renovation methods. In such projects, to ensure a good bond between the asphalt overlay and the original cement pavement and to eliminate the unevenness defects of the original pavement, milling is usually required. However, when the milling machine cutter rotates to the longitudinal and transverse joints or cracks of the cement slab, the cutter will bear uneven impact loads due to the lack of sufficient overall support on both sides of the joint. This hard-soft interface condition easily leads to destructive damage such as edge chipping, chipping, and corner breakage in the cement concrete on both sides of the joint. As a result, joints that were originally designed to be only 0.5-1 cm wide often expand into irregular pits with a width of 3-7 cm and a depth of 2-5 cm after actual milling.

[0003] Currently, the following methods are mainly used to address joints experiencing edge chipping and spalling: 1. Using traditional flexible joint filler materials (such as modified asphalt, polyurethane, and silicone). While these materials offer good elasticity and sealing, their low modulus, poor strength, and lack of structural support create a "soft cushion" area when filled into the widened joint. This area fails to provide effective support for the overlay asphalt layer. Under repeated vehicle loads, the overlay asphalt layer will deform and sink at the joint, accelerating reflective cracking and severely impacting the performance and lifespan of the "white-to-black" pavement. 2. Using rigid materials such as ordinary cement mortar or epoxy mortar, or semi-rigid materials like ordinary asphalt mixtures. While these materials provide sufficient support strength, their excessively high modulus results in insufficient deformation coordination. When the cement concrete slab expands and contracts due to temperature changes, these filler materials may break under pressure or detach from the joint walls under tension, forming cavities and ultimately damaging the overlay asphalt layer.

[0004] Therefore, finding a joint filler material that can simultaneously provide sufficient strength support and high coordinated deformation performance, specifically for filling joints and cracks in old cement concrete pavements caused by milling, has become a key technical issue for ensuring the quality of "white-to-black" projects and extending the service life of asphalt overlays. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a base filler material, preparation method, and application for the white-to-black overlay of cement pavement. It innovatively proposes classifying the aggregate of the filler material based on the size of the chipped joint defects. For small-sized joints, fine aggregate is combined with small-diameter elastic particles to ensure high filling density and good flexibility; for large-sized joints, coarse aggregate is combined with large-diameter elastic particles to provide effective support, achieving a precise match between material properties and engineering requirements.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a base filler material for the overlay of cement pavement after white-to-black conversion, comprising, by weight parts, 25-35 parts asphalt, 12-15 parts mineral powder, 25-40 parts aggregate, and 15-30 parts elastic particles, wherein the particle size of the mineral powder is <0.075 mm, the particle size of the aggregate is 1-3 mm or 3-5 mm, and the particle size of the elastic particles is 1-3 mm or 3-5 mm.

[0008] Preferably, when the maximum width of the joint is less than 5 cm and the maximum depth is less than 2.5 cm, the aggregate particle size is 1~3 mm and the elastic particle size is 1~3 mm.

[0009] Preferably, when the maximum width of the joint is ≥5 cm and the maximum depth is ≥2.5 cm, the aggregate particle size is 3~5 mm and the elastic particle size is 3~5 mm.

[0010] Preferably, when the maximum width of the joint is <5 cm and the maximum depth is ≥2.5 cm, or the maximum width is ≥5 cm and the maximum depth is <2.5 cm, the aggregates of 1~3 mm, rubber granules of 1~3 mm, aggregates of 3~5 mm and rubber granules of 3~5 mm are used in a mass ratio of 1:1:1:1.

[0011] Preferably, the asphalt material is modified asphalt, which, by weight, comprises 100 parts base asphalt, 2-4 parts lignin solution, 2-4 parts tackifying resin, 1-3 parts nano-montmorillonite, and 0.25-0.5 parts antioxidant.

[0012] More preferably, the base asphalt is No. 70 or No. 90 road petroleum asphalt, and the 25°C penetration of the base asphalt is 70~90mm.

[0013] More preferably, the tackifying resin includes C5 petroleum resin and / or C9 petroleum resin.

[0014] More preferably, the preparation method of asphalt material is as follows: Heat the base asphalt to 160~170℃ to allow the asphalt matrix to flow fully, and then maintain the temperature at 170~180℃. The base asphalt was sheared and stirred at 8000~10000 rpm. Nano-montmorillonite was added first and shearing continued to make the nano-montmorillonite uniformly dispersed in the base asphalt. Reduce the rotation speed to 6000~8000 rpm, then add the tackifying resin, lignin solution and antioxidant in sequence, and continue high-speed shearing until the mixture is uniform and fine with no visible particles. The mixture is stirred at 175~185℃ and 3000~4000 rpm to develop a stable modified asphalt.

[0015] In a second aspect, the present invention provides a method for preparing a base filler material for white-to-black overlay of cement pavement, comprising the following steps: The particle size of aggregate and elastic particles is determined based on the joint size. The aggregate is heated to 180~190℃ and the asphalt material is heated to 165~175℃. The elastic particles are dry-mixed with preheated aggregate, then asphalt is added and mixed wet, and finally mineral powder is added and mixed wet to obtain the base sealant.

[0016] In a third aspect of the invention, the invention proposes an application of a base filler material for the white-to-black overlay of cement pavement. The base filler material is allowed to flow naturally into the chipped joint, and the filling height is higher than the base surface of the cement concrete slab. The base filler material is then compacted to ensure that it fills the chipped joint densely and without gaps.

[0017] Preferably, the filling height of the base sealant is 0.3~0.5 cm higher than the base surface of the cement concrete slab.

[0018] Beneficial effects

[0019] This invention innovatively proposes to classify the aggregate of the joint filler material based on the size (i.e., width and depth) of the defect in the chipped joint. For small-sized joints, fine aggregate is used with small-diameter elastic particles to ensure high filling density and good flexibility. For large-sized joints, coarse aggregate is used with large-diameter elastic particles to provide effective support, thus achieving a precise match between material properties and engineering requirements.

[0020] This invention uses rigid aggregates and elastic particles of the same particle size to form the main skeleton. The aggregates are the main load-bearing components, providing sufficient strength to resist vertical deformation under vehicle load. The elastic particles are used as the elastic components, giving the skeleton good deformation recovery ability to coordinate the expansion and contraction of the cement board due to temperature, thus achieving the effect of "rigid skeleton does not crack and elastic skeleton does not sink".

[0021] The base sealant of this invention has a high asphalt content, exhibits good fluidity and plasticity at high temperatures, and is easy to inject and compact. In particular, it ensures the filling capacity of the base sealant for deep and narrow joints, effectively ensuring construction quality and results. The base sealant also has excellent anti-aging ability and durability, with a performance degradation rate during its service life that is far less than that of traditional sealant materials, effectively reducing maintenance costs and providing long-term economic benefits. Detailed Implementation

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, specific implementation methods of the present invention will be described below. Obviously, the following description is merely some embodiments of the present invention; those skilled in the art can obtain other implementation methods based on these embodiments without creative effort.

[0023] This invention proposes a base filler material for the overlay of cement pavement after white-to-black conversion. Calculated by mass parts, it includes 25-35 parts asphalt, 12-15 parts mineral powder, 25-40 parts aggregate, and 15-30 parts elastic particles. Among them, the particle size of the mineral powder is <0.075 mm, the particle size of the aggregate is 1-3 mm or 3-5 mm, and the particle size of the elastic particles is 1-3 mm or 3-5 mm.

[0024] In this invention, the specifications (i.e., particle size) of the aggregate and elastic particles are determined based on the geometric dimensions (width and depth) of the milled joint, specifically: When the maximum width of the joint is less than 5 cm and the maximum depth is less than 2.5 cm, use 1-3 mm aggregate and 1-3 mm rubber granules to build the skeleton of the base filling material; this corresponds to narrow and shallow joint defects, and pure small-particle-size materials can achieve a good filling effect. When the maximum width of the joint is ≥5 cm and the maximum depth is ≥2.5 cm, use 3~5 mm aggregate and 3~5 mm rubber granules to build the skeleton of the base filling material; this corresponds to a wide and deep joint defect, and pure large-particle material can achieve a good filling effect. When the maximum width of the joint is less than 5 cm and the maximum depth is greater than or equal to 2.5 cm, or the maximum width is greater than or equal to 5 cm and the maximum depth is less than 2.5 cm, a framework should be constructed by mixing 1-3 mm aggregate, 1-3 mm rubber granules, 3-5 mm aggregate, and 3-5 mm rubber granules in equal proportions (i.e., a mass ratio of 1:1:1:1). This corresponds to either wide and shallow or narrow and deep joint defects, and using a combination of large and small particle sizes will result in better filling.

[0025] This invention selects the appropriate particle size of the load-bearing skeleton aggregate (aggregate and rubber particles) based on the size of the joint defect, which can significantly improve the support and filling effect of the joint filler material. This invention mixes aggregates and elastic particles of the same particle size range as aggregates, forming a skeleton structure that balances strength and elasticity. The aggregates provide the main strength, while the elastic particles absorb and release the load capacity, ensuring support while avoiding the problem of excessive stiffness associated with a purely rigid skeleton. Furthermore, the use of aggregate gradation design with the same particle size and the intermittent addition of 0.075~1 mm fine aggregates ensures sufficient skeleton porosity in the formed skeleton structure. The composite adhesive system formed by high asphalt content and high mineral powder content (mineral powder particle size <0.075 mm in this invention) can freely and fully fill the skeleton porosity, ultimately forming a joint filler material with a strong skeleton and high density.

[0026] For narrower and shallower chipped joints, using fine-grained aggregate can ensure better support while densely filling the narrow space. For wider and deeper chipped joints, using coarse-grained aggregate can effectively ensure better support when filling a thicker area.

[0027] The aggregate is preferably crushed stone, such as diabase, limestone, basalt, etc., commonly used in road construction, forming the rigid part of the skeleton. The elastic particles are preferably rubber particles, forming the flexible elastic part of the skeleton. It should be noted that the particle size of the elastic particles used in this invention is much larger than that of the rubber materials used in conventional asphalt modification. After the elastic particles are mixed with the asphalt, they can still maintain their basic shape, that is, they can exert their elastic effect normally, without completely dissolving into the asphalt.

[0028] Based on the above-mentioned base sealant, the present invention also proposes a method for preparing the base sealant, comprising the following steps: Material preheating: Based on the joint size, determine the particle size of aggregate and elastic particles, heat the aggregate to 180~190℃, and heat the asphalt material to 165~175℃; Material mixing: Mix the elastic granules with the preheated aggregate, dry mix for 30-45 seconds, then add the asphalt material and mix wet for 45-60 seconds, finally add the mineral powder and continue to wet mix for 45-60 seconds to obtain the base filler material.

[0029] The base sealant prepared in the above manner is added into a cooker truck with heat insulation and self-mixing functions, and transported to the site for use. The base sealant is applied to road construction as follows: Before filling the joint, clean the dust and debris from the chipped joint and ensure that the joint walls are dry. Then, open the outlet of the cooker truck to allow the high-toughness base filler to flow naturally into the chipped joint. Fill the joint to a height higher than the cement concrete slab surface, preferably 0.3~0.5 cm higher. Finally, use a small road roller or vibratory tamping plate to compact the filler to ensure that the filler is densely packed and free of gaps in the chipped joint.

[0030] In this invention, the asphalt material can be a conventional modified asphalt material. A feasible asphalt material composition is proposed below. The asphalt material is an anti-aging modified asphalt, comprising, by weight, 100 parts base asphalt, 2-4 parts lignin solution, 2-4 parts tackifying resin, 1-3 parts nano-montmorillonite, and 0.25-0.5 parts antioxidant.

[0031] The preferred base asphalt is No. 70 or No. 90 road petroleum asphalt, and the 25°C penetration of the base asphalt is 70~90 mm.

[0032] Lignin is widely available and its cost is only 30-40% of that of polymer modifiers such as SBS and SBR, making it highly economical. The preferred lignin solution is obtained by purifying and acidifying lignin from papermaking black liquor. Its molecular structure contains abundant active antioxidant groups such as phenolic hydroxyl groups, alcoholic hydroxyl groups, and methoxyl groups. Adding lignin solution to the matrix asphalt can effectively delay the aging process of the asphalt. Furthermore, lignin, being a polymer, can increase the viscosity and adhesion of the asphalt, improve its temperature sensitivity, and enhance its high-temperature deformation resistance and water damage resistance. This invention utilizes lignin solution derived from papermaking black liquor, achieving high-value comprehensive utilization of solid waste materials. This not only significantly reduces the raw material cost but also aligns with the strategic direction of green and sustainable development, demonstrating significant economic and environmental benefits.

[0033] Tackifying resins include C5 petroleum resins and / or C9 petroleum resins. Tackifying resins are low-molecular-weight thermoplastic polymers with good compatibility with asphalt. They can significantly improve the cohesive strength of asphalt, and when combined with lignin solutions, further enhance the bonding strength of the asphalt, ensuring that the resulting joint filler forms a strong and durable bond with the joint, preventing interfacial delamination (i.e., debonding) under traffic loads and temperature stress, and improving the long-term service performance of the joint filler and the overlay asphalt layer.

[0034] Nano-montmorillonite is primarily used as a modifier and stabilizer for lignin solutions and tackifying resins. In the preparation of anti-aging modified asphalt, nano-montmorillonite is preferentially added to the base asphalt for high-speed shearing to form a uniform montmorillonite nanosheet dispersion system. Physical and chemical interactions exist between the montmorillonite nanosheets and the molecular chains of the lignin solution, tackifying resin, and other modifying components. The molecular chains of the modifying components insert into the montmorillonite nanosheets or adsorb onto their surface, thereby improving the compatibility of the lignin solution, tackifying resin, and other components with the base asphalt and effectively solving the segregation problem. Furthermore, the nano-montmorillonite sheets have a strong cross-linking effect on asphalt molecules, effectively preventing the migration and leakage of asphalt molecules and helping to delay the aging of the joint filler material.

[0035] Antioxidants are existing conventional materials, such as one or more of 4,6-bis(dodecylthiomethyl)o-cresol, 4,6-bis(octylthiomethyl)o-cresol, N-tert-butyl-2-naphthylamine, and 2,6-di-tert-butyl-4-cresol, which inhibit the oxidation reaction of asphalt molecules and help maintain the molecular structure and properties of asphalt.

[0036] Based on the above-mentioned anti-aging modified asphalt, this invention also proposes a corresponding preparation method, which involves mixing raw materials and preparing them by high-speed shearing, as follows: Heat the base asphalt to 160~170℃ to allow the asphalt matrix to flow fully, and then transfer the preheated base asphalt to a high-speed shearing machine, maintaining the temperature at 170~180℃. Start the high-speed shear machine and shear and mix at 8000~10000 rpm. First, add the nano-montmorillonite and shear at high speed for 10~15 minutes to make the nano-montmorillonite evenly dispersed in the base asphalt. Reduce the rotation speed to 6000~8000 rpm, then add the tackifying resin, lignin solution and antioxidant in sequence, and continue high-speed shearing for 45~60 min until the mixture is uniform and fine with no visible particles. The mixture is transferred to a development tank and stirred at a low speed of 3000-4000 rpm at 175-185℃ for 3-4 hours to allow the modified components to fully contact and fuse with the base asphalt, ultimately forming a stable anti-aging modified asphalt.

[0037] The technical solution of the present invention will be described in detail below with specific embodiments.

[0038] Example 1

[0039] The base joint material prepared in this embodiment is suitable for chipped joints with a maximum width of <5 cm and a maximum depth of <2.5 cm, i.e., the aggregate particle size is 1~3 mm and the elastic particle size is 1~3 mm.

[0040] This embodiment uses anti-aging modified asphalt, and the specific preparation method is as follows: Based on mass parts, the following ingredients are selected: 100 parts of 70# base bitumen, 3 parts of lignin solution, 2 parts of tackifying resin, 1.5 parts of nano-montmorillonite, and 0.3 parts of antioxidant. Heat 100 parts of 70# base asphalt to 165°C to make it flow fully, and transfer the preheated base asphalt to a high-speed shearing machine, keeping the temperature at 175°C. Start the high-speed shearing machine, adjust the speed to 8000 rpm, add 1.5 parts of nano-montmorillonite, and shear at high speed for 10 minutes to disperse it evenly; Set the high-speed shearing machine to 6000 rpm, add 3 parts lignin solution, 2 parts thickening resin and 0.3 parts antioxidant in sequence, and continue high-speed shearing for 50 minutes until the mixture is uniform and fine with no visible particles. The modified mixture is transferred to a development tank and stirred at low speed at 175°C for 3 hours to allow the modifier and base asphalt to fully react and fuse, ultimately forming a stable, anti-aging modified asphalt.

[0041] The preparation process and application of the high-toughness base sealant in this embodiment are as follows: Take 32 parts of anti-aging modified asphalt, 12 parts of mineral powder, 34 parts of 1-3mm diabase crushed stone (i.e., aggregate), and 22 parts of 1-3mm rubber granules (i.e., elastic granules).

[0042] The diabase crushed stone was heated to 185°C, and the anti-aging modified asphalt was heated to 175°C. Add the preheated diabase crushed stone and rubber granules to the mixing pot and dry mix for 30 seconds; then add the anti-aging modified asphalt and wet mix for 45 seconds; finally add the mineral powder and continue to wet mix for 60 seconds. Take the mixed high-toughness base sealant and mold it into various test specimens for comparative testing according to industry standards.

[0043] Example 2

[0044] The base joint material prepared in this embodiment is suitable for chipped joints with a maximum width ≥ 5 cm and a maximum depth ≥ 2.5 cm, i.e., the aggregate particle size is 3~5 mm and the elastic particle size is 3~5 mm.

[0045] This embodiment uses anti-aging modified asphalt, and the specific preparation method is as follows: Based on mass parts, the following ingredients are selected: 100 parts of 70# base bitumen, 4 parts of lignin solution, 5 parts of tackifying resin, 2.5 parts of nano-montmorillonite, and 0.5 parts of antioxidant. Heat 100 parts of 70# base asphalt to 165°C to make it flow fully, and transfer the preheated base asphalt to a high-speed shearing machine, keeping the temperature at 175°C. Start the high-speed shearing machine, adjust the speed to 8000 rpm, add 2.5 parts of nano-montmorillonite, and shear at high speed for 15 minutes to disperse it evenly; Set the high-speed shearing machine to 6000 rpm, add 4 parts lignin solution, 3 parts thickening resin and 0.5 parts antioxidant in sequence, and continue high-speed shearing for 60 minutes until the mixture is uniform and fine with no visible particles. The modified mixture is transferred to a development tank and stirred at low speed at 175°C for 4 hours to allow the modifier and base asphalt to fully react and fuse, ultimately forming a stable anti-aging modified asphalt.

[0046] The preparation process and application of the high-toughness base sealant in this embodiment are as follows: Take 30 parts of anti-aging modified asphalt, 12 parts of mineral powder, 38 parts of 3-5mm diabase crushed stone (i.e., aggregate), and 20 parts of 3-5mm rubber granules (i.e., elastic granules).

[0047] The diabase crushed stone was heated to 185°C, and the anti-aging modified asphalt was heated to 175°C. Add the preheated diabase crushed stone and rubber granules to the mixing pot and dry mix for 30 seconds; then add the anti-aging modified asphalt and wet mix for 50 seconds; finally add the mineral powder and continue to wet mix for 60 seconds. Take the mixed high-toughness base sealant and mold it into various test specimens for comparative testing according to industry standards.

[0048] Example 3

[0049] In this embodiment, conventional modified asphalt (ordinary SBS polymer modified asphalt (ID grade)) is used to replace the anti-aging modified asphalt in Example 2, and the remaining components and preparation steps are the same as in Example 2.

[0050] Comparative Example 1

[0051] Compared with Example 2, this example uses diabase crushed stone of the same mass and particle size range to replace rubber particles, while the remaining components and preparation steps are the same as in Example 2.

[0052] Comparative Example 2

[0053] Compared to Example 2, this example uses rubber particles of the same mass and particle size range to replace the diabase crushed stone. The remaining components and preparation steps are the same as in Example 2.

[0054] Comparative Example 3

[0055] This comparative example uses commercially available high-temperature filling type SBS modified asphalt sealant.

[0056] Comparative Example 4

[0057] This comparative example uses ordinary modified asphalt AC-10 mixture.

[0058] Performance tests were conducted on Examples 1-3 and Comparative Examples 1-4, and the results are shown in Table 1.

[0059] Table 1. Comparison of performance results between the examples and comparative examples.

[0060]

[0061] Note: Aging refers to the aging of asphalt materials using a PAV asphalt pressure aging device.

[0062] The anti-aging modified asphalt proposed in this invention (Examples 1, 2, Comparative Examples 1 and 2) showed lower penetration, ductility, and elastic recovery attenuation rates before and after aging than ordinary SBS polymer modified asphalt (Examples 3 and 4) and commercially available high-temperature filling type SBS modified asphalt sealant (Comparative Example 3). This indicates that the anti-aging formulation design of this invention is beneficial to improving the weather resistance and anti-aging performance of modified asphalt materials.

[0063] Comparative Example 3 is a pure SBS polymer-modified asphalt material. Experiments show that it does not have the support properties of a mixture and cannot be directly used for filling joints and cracks where edge chipping has occurred. Comparative Example 4 is a modified asphalt AC-10 mixture. Although it has relatively high rutting dynamic stability (i.e., strong support), its low-temperature bending failure strain and four-point bending fatigue life are at a low level. It cannot provide sufficient low-temperature coordinated deformation and fatigue crack resistance. Directly using it for filling joints and cracks where edge chipping has occurred will cause problems such as compression failure or detachment of the cement concrete slab from the filling material due to thermal expansion and contraction. From the three indicators of dynamic stability, low-temperature bending failure strain, and four-point bending fatigue life in Examples 1-3, it can be seen that the composite interlocking skeleton of crushed stone and rubber particles can better balance the supporting mechanical properties (dynamic stability of approximately 676-830 cycles / mm), crack resistance (failure strain of approximately 7710-8533 με), and fatigue resistance (540,000-620,000 cycles) of the joint filler material. Comparative Example 1 uses pure crushed stone to build the mixed skeleton. Although the supporting mechanical properties are improved (dynamic stability increased to 1357 cycles / mm), its crack resistance and fatigue resistance are both reduced. Comparative Example 2 uses pure rubber particles to build the mixed skeleton. It can be seen that its crack resistance is not significantly different from Examples 1-3, and its fatigue resistance is further improved, but its supporting mechanical properties are significantly reduced (dynamic stability decreased to 213 mm / cycle). Therefore, it can be concluded that the base joint filler material formed by the method proposed in this invention is a tough material that combines supporting performance with crack resistance and fatigue resistance, and is especially suitable for joint treatment before the white-to-black conversion of cement concrete pavements.

[0064] The embodiments provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention, and the descriptions of the embodiments above are only for the purpose of helping to understand the core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A base-filling material for cement pavement whitening and black covering, characterized by, The asphalt material is 25-35 parts by mass, the mineral powder is 12-15 parts by mass, the aggregate is 25-40 parts by mass, and the elastic particles are 15-30 parts by mass, wherein the particle size of the mineral powder is less than 0.075 mm, the particle size of the aggregate is 1-3 mm or 3-5 mm, and the particle size of the elastic particles is 1-3 mm or 3-5 mm.

2. The underfill material of claim 1, wherein When the maximum width of the joint is less than 5 cm and the maximum depth is less than 2.5 cm, the particle size of the aggregate is 1-3 mm, and the particle size of the elastic particles is 1-3 mm.

3. The underfill material of claim 1, wherein When the maximum width of the joint is greater than or equal to 5 cm and the maximum depth is greater than or equal to 2.5 cm, the particle size of the aggregate is 3-5 mm, and the particle size of the elastic particles is 3-5 mm.

4. The underfill material of claim 1, wherein When the maximum width of the joint is less than 5 cm and the maximum depth is greater than or equal to 2.5 cm, or the maximum width is greater than or equal to 5 cm and the maximum depth is less than 2.5 cm, the aggregate of 1-3 mm, the rubber particles of 1-3 mm, the aggregate of 3-5 mm, and the rubber particles of 3-5 mm are used in a mass ratio of 1:1:1:

1.

5. The underfill material according to any one of claims 1 to 4, wherein The asphalt material is 25-35 parts by mass, the mineral powder is 12-15 parts by mass, the aggregate is 25-40 parts by mass, and the elastic particles are 15-30 parts by mass, wherein the particle size of the mineral powder is less than 0.075 mm, the particle size of the aggregate is 1-3 mm or 3-5 mm, and the particle size of the elastic particles is 1-3 mm or 3-5 mm.

6. The underfill material of claim 5, wherein The asphalt material is 25-35 parts by mass, the mineral powder is 12-15 parts by mass, the aggregate is 25-40 parts by mass, and the elastic particles are 15-30 parts by mass, wherein the particle size of the mineral powder is less than 0.075 mm, the particle size of the aggregate is 1-3 mm or 3-5 mm, and the particle size of the elastic particles is 1-3 mm or 3-5 mm.

7. The underfill material of claim 5, wherein The base filler material is prepared by the following steps:

8. The underseal material of claim 5, wherein the bitumen is The base filler material is prepared by the following steps: The base filler material is prepared by the following steps: The base filler material is prepared by the following steps: The base filler material is prepared by the following steps: The base filler material is prepared by the following steps:

9. A method for preparing a base-filling material for cement pavement whitening black overlay, characterized by, The base filler material is prepared by the following steps: The base filler material is prepared by the following steps: The base filler material is prepared by the following steps:

10. 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