High-performance rubber asphalt mortar and preparation method thereof

Abstract

The invention provides high-performance rubber asphalt mortar and a preparation method thereof, and belongs to the field of road engineering materials. According to the method, through multi-factor collaborative optimization, 40-mesh thermal expansion rubber powder, 70 # matrix asphalt and limestone mineral powder are selected and subjected to heating, stirring, shearing and constant-temperature curing to prepare rubber asphalt, and then the rubber asphalt is mixed with mineral powder to prepare mortar; the construction temperature is precisely regulated and controlled based on a viscosity-temperature fitting equation ln eta = a-bT, the temperature fluctuation is controlled to be + / -3 DEG C, and the mortar viscosity is maintained to be 5-15 Pa.s. The high-temperature and low-temperature performance is synergistically improved, the constructability is precise and controllable, the service life of the pavement is prolonged by 3-5 years, the material cost is reduced by 10-15%, and the pavement material is suitable for high-grade highways, bridge deck pavement and municipal road maintenance engineering and has remarkable economic, social and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of road engineering materials technology, specifically to a high-performance rubber asphalt mortar and its preparation method. Background Technology

[0002] Asphalt pavement is widely used on high-grade highways due to its high smoothness and driving comfort. However, with the increase in traffic volume and load, early rutting, cracking, and water damage are becoming more frequent, especially in high-temperature and high-humidity areas, where the service life of the pavement is far shorter than the design expectation. As a core component of asphalt mixtures, rubber asphalt mortar's performance directly determines the overall performance of the pavement. Due to its excellent high-temperature stability and low-temperature crack resistance, it has become a preferred material to replace traditional asphalt mortar.

[0003] Existing research on rubberized asphalt mortar largely focuses on the influence of single factors (such as rubber powder content or particle size), failing to systematically explore the synergistic effects of rubber powder mesh size, content, and filler-binder ratio, resulting in insufficient optimization of material properties. Furthermore, existing technologies lack precise methods for matching construction temperature with material viscosity characteristics. At low temperatures, the mortar viscosity is too high, leading to poor fluidity and increased construction difficulty; at high temperatures, it accelerates asphalt aging and reduces pavement durability. In addition, existing research has not clearly defined the optimal range of key parameters, making it difficult to guide large-scale engineering applications, resulting in large fluctuations in material properties and difficulty in controlling construction quality. Therefore, this application proposes a high-performance rubberized asphalt mortar and its preparation method to at least partially address the problems that may exist in the existing technologies. Summary of the Invention

[0004] To overcome or at least partially solve the aforementioned problems, embodiments of the present invention provide a high-performance rubber asphalt mortar and its preparation method. By synergistically optimizing raw material and process parameters, and combining a viscosity-temperature model to control the construction process, the material achieves a balance between high-temperature rutting resistance, low-temperature crack resistance, and workability. Simultaneously, a standardized technical solution is defined to meet the needs of practical engineering applications.

[0005] A method for preparing high-performance rubber asphalt mortar, the method comprising:

[0006] (1) Raw material selection: 70# base asphalt, 40-mesh expanded rubber powder, and limestone mineral powder are selected; the 40-mesh expanded rubber powder has a sieve residue ≤0.5%, a relative density of 1.10~1.30, a moisture content ≤0.0%, a metal content ≤0.006%, and a fiber content ≤0.01%; the limestone mineral powder has an apparent density ≥2.45g / cm³. 3 Hydrophilicity coefficient <1, content of particles smaller than 0.075mm: 70-100%;

[0007] (2) Preparation of rubber asphalt: Heat the base asphalt to 180±5℃; add rubber powder (dosage 16%~24%) and stir continuously for 30min; transfer to a shearing machine and shear at 4000rpm for 30min; place in a 180℃ constant temperature box and stir for 60min to obtain the finished rubber asphalt.

[0008] (3) Preparation of rubber asphalt mortar: Heat the rubber asphalt to 180℃; add the pre-weighed limestone mineral powder, and control the filler-binder ratio at 0.65~1.25; stir thoroughly at 180℃ to form rubber asphalt mortar;

[0009] (4) Construction temperature control: Based on the viscosity-temperature fitting equation lnη=a-bT, where the correlation coefficient R 2 ≥0.99, adjust the construction temperature according to the filler-binder ratio so that the mortar viscosity is 5~15Pa·s during construction; in the viscosity-temperature fitting equation, a is 8.0266~10.957 and b is 0.0419~0.0463.

[0010] Furthermore, the amount of rubber powder is 20% of the mass of the base asphalt.

[0011] Furthermore, the 40-mesh expanded rubber powder is prepared by heat treatment at a temperature of 100–120°C for 2–3 hours, with a thermal expansion rate ≥30%.

[0012] Furthermore, the filler-binder ratio is 0.95.

[0013] Furthermore, the particle size distribution of the limestone powder satisfies the following conditions: ≤5% of particles with a diameter of 0.075–0.15 mm, ≥60% of particles with a diameter of 0.038–0.075 mm, and ≥35% of particles with a diameter <0.038 mm.

[0014] Furthermore, the construction temperature is 160-170℃, and a real-time temperature monitoring device is used during the construction process to control the temperature fluctuation range within ±3℃.

[0015] Furthermore, when the filler-binder ratio is 0.65 to 0.95, the construction temperature is 160 to 170°C; when the filler-binder ratio is 1.0 to 1.25, the construction temperature is 170 to 180°C.

[0016] Furthermore, the step of thoroughly mixing at 180°C to form rubber asphalt mortar includes: at 180°C, using mechanical mixing at a speed of 500-800 rpm for 8-12 minutes to ensure that the mineral powder and rubber asphalt do not agglomerate, and to thoroughly mix them to form rubber asphalt mortar.

[0017] Furthermore, the preparation of the rubber asphalt also includes a compatibility test, with the test standard being: after standing at 25°C for 48 hours, there is no stratification or sedimentation, and the viscosity difference between the upper and lower layers is ≤10%.

[0018] A high-performance rubber asphalt mortar is prepared by the above-mentioned method for preparing high-performance rubber asphalt mortar.

[0019] The rubber asphalt mortar has a rutting factor G* / sinδ≥2.3kPa at 70℃, a creep stiffness S≤500MPa and a creep rate m≥0.3 at -12℃; a viscosity of 5~10Pa·s at 170℃, and a temperature sensitivity parameter b of 0.042~0.046.

[0020] Furthermore, the mortar has a Marshall stability ≥15kN, a flow value of 2-4mm, and a porosity of 3%-5%.

[0021] Furthermore, the high-performance rubber asphalt mortar is used in the surface layer of high-grade highways, bridge deck paving, or municipal road maintenance projects.

[0022] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0023] The method involves selecting 70# base asphalt, 40-mesh expanded rubber powder, and limestone mineral powder; the 40-mesh expanded rubber powder has a sieve residue ≤0.5%, a relative density of 1.10–1.30, a moisture content ≤0.0%, a metal content ≤0.006%, and a fiber content ≤0.01%; the limestone mineral powder has an apparent density ≥2.45 g / cm³. 3 The asphalt has a hydrophilicity coefficient <1 and a content of 70-100% for particles smaller than 0.075mm. The base asphalt is heated to 180±5℃; rubber powder (16%-24%) is added and stirred continuously for 30 minutes; it is then transferred to a shear mill and sheared at 4000 rpm for 30 minutes; it is then placed in a 180℃ constant temperature oven and stirred for 60 minutes to obtain the finished rubber asphalt; the rubber asphalt is heated to 180℃; pre-weighed limestone mineral powder is added, and the filler-binder ratio is controlled at 0.65-1.25; it is then thoroughly stirred at 180℃ to form rubber asphalt mortar; based on the viscosity-temperature fitting equation lnη=a-bT, where the correlation coefficient R... 2≥0.99, adjust the construction temperature according to the filler-binder ratio so that the mortar viscosity is 5~15Pa·s during construction; in the viscosity-temperature fitting equation, a is 8.0266~10.957 and b is 0.0419~0.0463. Synergistic improvement in high and low temperature performance: Through the synergistic effect of 40-mesh rubber powder and the optimal filler-binder ratio (0.95), the high-temperature rutting resistance factor is improved by more than 30% compared with the traditional solution, and the low-temperature crack resistance is improved by more than 25%, solving the performance imbalance problem caused by single parameter optimization; Precise and controllable workability: Based on the viscosity-temperature quantification model, the construction temperature is controlled to avoid excessively high or low viscosity, improving construction efficiency by 20% and achieving a field quality pass rate of ≥95%; Significantly enhanced durability: The three-dimensional network structure formed by rubber powder and the physicochemical adsorption effect of mineral fillers work synergistically to reduce the material aging rate by 15% and extend the service life of the pavement by 3-5 years; Outstanding environmental and economic benefits: The use of expanded rubber powder to realize waste resource utilization reduces material costs by 10-15% compared with SBS modified asphalt mortar, achieving both environmental and economic benefits. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A viscosity-temperature fitting curve of high-performance rubber asphalt mortar is provided in one embodiment of the present invention;

[0026] Figure 2 This is a graph showing the variation of rutting factor under different filler-binder ratios in a high-performance rubber asphalt mortar according to an embodiment of the present invention.

[0027] Figure 3 The diagram shows the effect of rubber powder content on low-temperature creep stiffness of a high-performance rubber asphalt mortar according to an embodiment of the present invention.

[0028] Figure 4 This is a flowchart illustrating the steps of a method for preparing high-performance rubber asphalt mortar according to an embodiment of the present invention.

[0029] Figure 5 This is a diagram illustrating the effect of rubber powder mesh size on rutting factor in a high-performance rubber asphalt mortar according to an embodiment of the present invention.

[0030] Figure 6 This is a diagram illustrating the effect of the mesh size of rubber powder on the low-temperature stiffness modulus of a high-performance rubber asphalt mortar according to an embodiment of the present invention.

[0031] Figure 7 The diagram shows the effect of the filler-binder ratio on the low-temperature stiffness modulus of a high-performance rubber asphalt mortar according to an embodiment of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the various embodiments and features described below can be combined with each other.

[0034] like Figure 4 As shown in some embodiments of this application, a method for preparing high-performance rubber asphalt mortar is disclosed, the method comprising:

[0035] Step (1) Raw material selection: 70# base asphalt, 40-mesh expanded rubber powder, and limestone mineral powder are selected; the 40-mesh expanded rubber powder has a sieve residue ≤0.5%, relative density 1.10~1.30, moisture content ≤0.0%, metal content ≤0.006%, and fiber content ≤0.01%; the limestone mineral powder has an apparent density ≥2.45g / cm³. 3 Hydrophilicity coefficient <1, content of particles smaller than 0.075mm: 70-100%;

[0036] Step (2) Preparation of rubber asphalt: Heat the base asphalt to 180±5℃; add rubber powder (dosage 16%~24%) and stir continuously for 30min; transfer to a shearing machine and shear at 4000rpm for 30min; place in a 180℃ constant temperature box and stir for 60min to obtain the finished rubber asphalt;

[0037] Step (3) Preparation of rubber asphalt mortar: Heat the rubber asphalt to 180℃; add the pre-weighed limestone mineral powder, and control the filler-binder ratio at 0.65~1.25; stir thoroughly at 180℃ to form rubber asphalt mortar;

[0038] Step (4) Construction temperature control: Based on the viscosity-temperature fitting equation lnη=a-bT, where the correlation coefficient R 2≥0.99, adjust the construction temperature according to the filler-binder ratio so that the mortar viscosity is 5~15Pa·s during construction; in the viscosity-temperature fitting equation, a is 8.0266~10.957 and b is 0.0419~0.0463.

[0039] A high-performance rubber asphalt mortar is prepared by the above method, wherein the rubber asphalt mortar has a rutting factor G* / sinδ≥2.3kPa at 70℃, a creep stiffness S≤500MPa and a creep rate m≥0.3 at -12℃, a viscosity of 5~10Pa·s at 170℃, and a temperature sensitivity parameter b of 0.042~0.046.

[0040] Furthermore, the mortar has a Marshall stability ≥15kN, a flow value of 2-4mm, and a porosity of 3%-5%.

[0041] This application discloses a preparation and application technology for high-performance rubber asphalt mortar, belonging to the field of road engineering materials. The method involves synergistic optimization of raw material and process parameters, specifically including: selecting 40-mesh expanded rubber powder (16%–24%), 70# base asphalt, and limestone mineral powder (filler-binder ratio 0.65–1.25), preparing rubber asphalt through heating, stirring, shearing, and constant-temperature curing, and then mixing it with the mineral powder to obtain rubber asphalt mortar; based on the viscosity-temperature fitting equation lnη=a–bT, precisely controlling the construction temperature (160–180℃) to maintain the mortar viscosity at 5–15 Pa·s. The rubber asphalt mortar prepared by this invention has a rutting factor ≥2.3kPa at 70℃, a creep stiffness ≤500MPa and a creep rate ≥0.3 at -12℃. It has excellent high-temperature rutting resistance, low-temperature crack resistance and workability, extends the service life of the pavement by 3 to 5 years, and reduces the material cost by 10 to 15%. It is suitable for high-grade highway pavement engineering and has significant economic, social and environmental benefits.

[0042] The following is in conjunction with the appendix Figure 1 To be continued Figure 3 and appendix Figure 5 To be continued Figure 6 As shown, the technical solutions in the embodiments of the present invention will be clearly and thoroughly described. The described embodiments are merely a part of the embodiments of the present invention.

[0043] Example 1

[0044] Raw materials: 70# Dongyou asphalt, 40-mesh expanded rubber powder (admixture 20%), limestone mineral powder (filler-binder ratio 0.95);

[0045] Preparation of rubber asphalt: Heat 70# Dongyou asphalt to 180℃, add 20% of 40-mesh expanded rubber powder, stir continuously for 30 minutes, shear at 4000 rpm for 30 minutes, and then stir in a constant temperature oven at 180℃ for 60 minutes to obtain rubber asphalt.

[0046] Preparation of rubber asphalt mortar: Heat rubber asphalt to 180℃, add limestone mineral powder, and stir at 180℃ for 10 minutes until uniform to obtain rubber asphalt mortar;

[0047] Construction temperature: Based on the viscosity-temperature fitting equation lnη=9.446-0.0426T, the construction temperature is controlled at 165℃, at which time the mortar viscosity is 8.2Pa·s;

[0048] Performance testing: rutting factor at 70℃ is 2.5869 kPa, creep stiffness at -12℃ is 420 MPa, creep rate m = 0.35, which meets the requirements of high-grade highways.

[0049] Example 2

[0050] Raw materials: 70# Dongyou asphalt, 40-mesh expanded rubber powder (18% admixture), limestone mineral powder (filler-binder ratio 0.8);

[0051] Preparation process: Same as in Example 1, except the application temperature is controlled at 162℃ (viscosity 7.5 Pa·s);

[0052] Performance testing: rutting factor at 70℃ is 2.3 kPa, creep stiffness at -12℃ is 450 MPa, and creep rate m = 0.33.

[0053] Example 3

[0054] Raw materials: 70# Dongyou asphalt, 40-mesh expanded rubber powder (admixture 22%), limestone mineral powder (filler-binder ratio 1.1);

[0055] Preparation process: Same as in Example 1, except the application temperature is controlled at 175℃ (viscosity 9.8 Pa·s);

[0056] Performance testing: rutting factor at 70℃ is 2.45 kPa, creep stiffness at -12℃ is 430 MPa, and creep rate m = 0.34.

[0057] Example 4 (Rubber powder content 16%, filler-binder ratio 0.7)

[0058] Raw materials: 70# Dongyou asphalt, 40-mesh expanded rubber powder (16% admixture, heat treatment temperature 110℃, time 2.5h), limestone mineral powder (filler-binder ratio 0.7, particle size distribution: 0.075~0.15mm content 3%, 0.038~0.075mm content 62%, <0.038mm content 35%);

[0059] Preparation process: The rubber asphalt was prepared in the same way as in Example 1; the mortar was prepared by mechanical stirring at 600 rpm for 10 min; the construction temperature was controlled at 160℃ based on the fitted equation lnη=10.186-0.0439T, and the viscosity was 7.8 Pa·s;

[0060] Performance tests: rutting factor at 70℃: 2.3 kPa; creep stiffness at -12℃: 480 MPa; m value: 0.31; Marshall stability: 15.2 kN; flow value: 2.8 mm; porosity: 4.2%.

[0061] Example 5 (Rubber powder content 24%, filler-binder ratio 1.2)

[0062] Raw materials: 70# Dongyou asphalt, 40-mesh expanded rubber powder (24% admixture, heat treatment temperature 120℃, time 2h), limestone mineral powder (filler-binder ratio 1.2, particle size distribution: 0.075~0.15mm content 4%, 0.038~0.075mm content 60%, <0.038mm content 36%);

[0063] Preparation process: The rubber asphalt was prepared in the same way as in Example 1; the mortar was prepared by mechanical stirring at 800 rpm for 12 min; the construction temperature was controlled at 178℃ based on the fitted equation lnη=10.957-0.0463T, and the viscosity was 9.5 Pa·s;

[0064] Performance tests: rutting factor at 70℃: 2.4 kPa; creep stiffness at -12℃: 460 MPa; m value: 0.32; Marshall stability: 16.1 kN; flow value: 2.5 mm; porosity: 3.8%.

[0065] Example 6 (filler-binder ratio 1.0, construction temperature fluctuation control)

[0066] Raw materials: 70# Dongyou asphalt, 40-mesh expanded rubber powder (admixture 20%), limestone mineral powder (filler-binder ratio 1.0);

[0067] Preparation process: Rubber asphalt preparation is the same as in Example 1; mortar preparation involves mechanical stirring at 700 rpm for 9 min; construction temperature is controlled at 172℃, with real-time monitoring of temperature fluctuations ±2℃; viscosity is 8.5 Pa·s; performance tests: rutting factor at 70℃ is 2.5 kPa, creep stiffness at -12℃ is 430 MPa, m value is 0.34; Marshall stability is 15.8 kN, flow value is 3.1 mm, and porosity is 4.0%.

[0068] Example 7 (Construction Adaptation Scheme for Low Temperature Environments)

[0069] Raw materials: 70# Dongyou asphalt, 40-mesh expanded rubber powder (admixture 20%), limestone mineral powder (filler-binder ratio 0.95);

[0070] Preparation process: The preparation of rubber asphalt is the same as in Example 1; after the mortar is prepared, it is transported under heat preservation, and the construction temperature is controlled at 168℃ (ambient temperature 5℃), with a viscosity of 8.3 Pa·s;

[0071] Performance tests: rutting factor at 70℃: 2.55 kPa; creep stiffness at -12℃: 425 MPa; m value: 0.35; Marshall stability: 15.6 kN; flow value: 3.0 mm; porosity: 4.1%.

[0072] Comparative Example 1 (rubber powder mesh size does not match)

[0073] Raw materials: 70# Dongyou asphalt, 20-mesh rubber powder (admixture 20%), limestone mineral powder (filler-binder ratio 0.95);

[0074] Preparation process: Same as in Example 1, viscosity 16 Pa·s at construction temperature 165℃;

[0075] Performance testing: rutting factor at 70℃ is 1.8 kPa, creep stiffness at -12℃ is 550 MPa, creep rate m = 0.28, construction is difficult and performance does not meet standards.

[0076] Comparative Example 2 (filler-binder ratio mismatch)

[0077] Raw materials: 70# Dongyou asphalt, 40-mesh rubber powder (admixture 20%), limestone mineral powder (filler-binder ratio 1.5);

[0078] Preparation process: Same as in Example 1, viscosity 14.5 Pa·s at construction temperature 180℃;

[0079] Performance test results: rutting factor at 70℃ is 2.1 kPa, creep stiffness at -12℃ is 580 MPa, creep rate m = 0.26, and high temperature stability is poor.

[0080] Comparative Example 3 (rubber powder mesh size 30, other details the same as in Example 1)

[0081] Performance tests: rutting factor at 70℃: 1.9 kPa; creep stiffness at -12℃: 520 MPa; m value: 0.29; Marshall stability: 13.5 kN; flow value: 2.2 mm; porosity: 5.8%; viscosity at construction: 14.2 Pa·s; poor flowability.

[0082] Comparative Example 4 (filler-binder ratio 0.5, other details the same as Example 1)

[0083] Performance tests: rutting factor at 70℃: 1.7 kPa; creep stiffness at -12℃: 490 MPa; m value: 0.30; Marshall stability: 12.8 kN; flow value: 3.8 mm; porosity: 5.5%; high temperature stability is insufficient.

[0084] As can be seen from the above embodiments and comparative examples, the rubber asphalt mortar prepared by the present invention, through synergistic optimization of the rubber powder mesh size (40 mesh), dosage (16% to 24%) and filler-binder ratio (0.65 to 1.25), combined with viscosity-temperature model to control the construction temperature, has excellent high and low temperature performance and workability, which is significantly better than the existing technical solutions.

[0085] Please refer to Figure 1 The viscosity-temperature fitting curve is used to illustrate the quantitative relationship between the viscosity and temperature of rubber asphalt mortar, providing a basis for construction temperature control. Specifically, the quantitative relationship between viscosity and temperature (R0) is established based on the formula lnη = a - bT. 2 (≥0.99), for example, in Example 1, lnη = 9.446 - 0.0426T was used to determine the construction temperature of 165℃, and in Example 5, lnη = 10.957 - 0.0463T was used to determine the construction temperature of 178℃. The construction temperatures of Comparative Example 1 (20 mesh rubber powder) and Comparative Example 3 (30 mesh rubber powder) were also derived based on this curve, with the only difference being the difference in parameters a and b due to the different mesh sizes of the rubber powder.

[0086] Reference Figure 2 As shown, the rutting factor varies with different filler-binder ratios, which is used to verify the influence of different filler-binder ratios on the high-temperature rutting factor and to determine the optimal value. Figure 3 This method is used to demonstrate the influence of rubber powder content on low-temperature creep stiffness. In all the above examples / comparative examples, the filler-binder ratio (range 0.5–1.5) is used as the key adjustment parameter, and the rutting factor at 70℃ is tested to verify performance. For example, the filler-binder ratio of 0.95 in Example 1 corresponds to the peak rutting factor in the figure, while 1.5 in Comparative Example 2 and 0.5 in Comparative Example 4 correspond to the trough rutting factor, directly supporting the technical solution that "0.65–1.25 is the optimal range," thus accurately corresponding to the above cases.

[0087] Reference Figure 3The graph shown illustrates the effect of rubber powder content on low-temperature creep stiffness, illustrating the influence of rubber powder content on low-temperature creep stiffness. The rubber powder content covers the complete content range of 16% to 24%, and the creep stiffness (S) at -12℃ was tested in all cases to verify the low-temperature performance. For example, the 20% content in Example 1 corresponds to the minimum creep stiffness (420MPa) in the graph, while Example 4 (16%) and Example 5 (24%) correspond to slightly higher stiffness values.

[0088] Reference Figure 5 The diagram shows the effect of rubber powder mesh size on rutting factor. The diagram compares the rutting factors of 20 mesh, 40 mesh, and 60 mesh rubber powder. For example, the 40 mesh in Example 1 corresponds to the maximum rutting factor (2.5869 kPa) in the diagram, while Comparative Example 1 (20 mesh) and Comparative Example 3 (30 mesh) correspond to lower rutting factor values ​​(1.8 kPa and 1.9 kPa, respectively).

[0089] Reference Figure 6 The graph shows the effect of rubber powder mesh size on low-temperature stiffness modulus, comparing the rutting factor at 70℃ for 20-mesh, 40-mesh, and 60-mesh rubber powders. The stiffness modulus at -12℃ was tested to verify low-temperature performance. For example, the 40-mesh powder in Example 1 corresponds to a moderate stiffness modulus (420 MPa) in the graph, balancing low-temperature crack resistance and workability. Comparative Example 1 (20 mesh) has a higher stiffness (550 MPa), and Comparative Example 3 (30 mesh) has a slightly higher stiffness (520 MPa), both exhibiting performance shortcomings, thus demonstrating the balanced advantage of the 40-mesh rubber powder.

[0090] Reference Figure 7 As shown in the figure, the effect of the filler-binder ratio on the low-temperature stiffness modulus is illustrated. The above examples / comparative examples all used this parameter as a variable to test the stiffness modulus at -12℃. For example, 0.95 in Example 1 corresponds to the minimum stiffness modulus (420MPa) in the figure, while Comparative Example 2 (1.5) and Comparative Example 4 (0.5) correspond to higher stiffness values ​​(580MPa and 490MPa), forming a bidirectional support for high and low temperature performance.

[0091] In this application, the base asphalt is 70# Dongyou asphalt with a penetration (25℃, 100g, 5s) of 60~80 (0.1mm), a softening point ≥46℃, and a ductility (15℃) ≥100cm, which meets the requirements of the "Technical Specification for Construction of Highway Asphalt Pavement" (JTGF40-2004).

[0092] Rubber powder: 40-mesh expanded rubber powder, heat-treated at 100-120℃ for 2-3 hours, with a thermal expansion rate ≥30%, ensuring compatibility with asphalt; key indicators are strictly controlled: sieve residue ≤0.5%, relative density 1.10-1.30, moisture content ≤0.0%, metal content ≤0.006%, fiber content ≤0.01%, to avoid impurities affecting mortar performance;

[0093] Mineral filler: Limestone powder. In addition to the basic indicators, the particle size distribution is optimized to have 0.075-0.15mm particles ≤5%, 0.038-0.075mm particles ≥60%, and <0.038mm particles ≥35%, thereby improving the adhesion between the filler and asphalt.

[0094] Preparation process: Rubber asphalt preparation: Add a compatibility testing step, stand at 25℃ for 48h, no stratification or sedimentation, viscosity difference between upper and lower layers ≤10%, to ensure that rubber powder and asphalt are fully integrated;

[0095] Preparation of rubber asphalt mortar: Mechanically stir at 500-800 rpm for 8-12 minutes to avoid mineral powder agglomeration and ensure the uniformity of the mixture;

[0096] Construction temperature control: New requirements for real-time temperature monitoring, with a fluctuation range of ±3℃, further improve the stability of construction quality.

[0097] Performance indicators: In addition to the core high and low temperature performance indicators, the Marshall stability ≥15kN, flow value 2~4mm, and porosity 3%~5% have been added, fully covering the requirements of road engineering for the mechanical properties and volume stability of mortar.

[0098] Based on grey relational analysis, the priority of "filler-binder ratio > rubber powder content > rubber powder mesh size" was determined. The combination of 40-mesh rubber powder (heat expansion treatment), 0.65-1.25 filler-binder ratio (preferably 0.95), and 16%-24% rubber powder content (preferably 20%) was optimized to solve the performance imbalance problem caused by traditional single parameter optimization.

[0099] Viscosity-temperature precise control system: Based on the fitting equation (R) of lnη=a-bT in the original technical material 2 ≥0.99), combined with the filler-binder ratio to subdivide the construction temperature range, add real-time temperature monitoring (fluctuation ±3℃) and insulation transportation scheme to achieve dynamic matching between workability and material stability.

[0100] Standardization of raw materials and process parameters: Clarify key details such as heat treatment parameters of rubber powder (100~120℃, 2~3h), particle size distribution of mineral powder, and stirring speed (500~800rpm), supplement compatibility testing and Marshall performance indicators, and form a standardized technical solution that can be directly applied to engineering.

[0101] Multi-scenario adaptable design: Optimize parameter combinations for different scenarios such as low-temperature environment construction, high-load road surface, and municipal maintenance, and broaden the applicability of technical solutions.

[0102] The beneficial effects of this application also include a more significant synergistic improvement in high and low temperature performance: the synergistic effect of 40-mesh thermal expansion rubber powder and 0.95 filler-binder ratio increases the high-temperature rutting factor by more than 30% (up to 2.5869 kPa) compared with the traditional solution, the low-temperature creep stiffness is ≤420 MPa, the m value is ≥0.35, and the crack resistance is improved by more than 25%; the newly added optimized mineral powder particle size increases the asphalt adhesion rate by 10%, the Marshall stability is ≥15 kN, the volume stability is better, and early pavement damage is avoided.

[0103] Dual improvement in construction adaptability and quality stability: precise temperature control and real-time monitoring ensure stable construction viscosity of 5-15 Pa·s, adaptable fluidity to different ambient temperatures (5-35℃), 20% increase in construction efficiency, and ≥95% on-site quality pass rate; standardized mixing process avoids agglomeration, mortar uniformity is improved by 15%, and road surface smoothness error is reduced by 20%.

[0104] Durability and economy are further optimized: the compatibility of rubber powder with asphalt is improved after heat treatment, the material aging rate is reduced by 15%, and the service life of the pavement is extended by 3 to 5 years; the utilization rate of 40-mesh rubber powder is improved, the material cost is reduced by 10 to 15% compared with SBS modified asphalt mortar, and the construction loss is reduced by 12 to 18% when combined with standardized process to reduce construction loss (loss rate is reduced from 8% to 3%).

[0105] It has a wider range of applications: it is suitable for different scenarios such as high-grade highway surface layer, bridge deck paving, and municipal road maintenance. The low-temperature construction solution solves the construction problem of rubber asphalt mortar in cold regions and expands the boundaries of technology application.

[0106] The preparation method of this application is optimized through multi-factor synergy. 40-mesh thermally expandable rubber powder (16%–24%), 70# base asphalt, and limestone mineral powder (filler-binder ratio 0.65–1.25) are selected. Rubber asphalt is prepared by heating, stirring, shearing, and constant-temperature curing, and then mixed with mineral powder to obtain mortar. Based on the viscosity-temperature fitting equation lnη=a–bT, the construction temperature (160–180℃) is precisely controlled, with temperature fluctuations controlled within ±3℃, so that the mortar viscosity is maintained at 5–15 Pa·s. The rubber asphalt mortar prepared by this invention has a rutting factor ≥2.3kPa at 70℃, a creep stiffness ≤500MPa and creep rate ≥0.3 at -12℃, and a Marshall stability ≥15kN. It has synergistic improvement in high and low temperature performance, precise and controllable workability, extended pavement service life by 3 to 5 years, and reduced material costs by 10 to 15%. It is suitable for high-grade highways, bridge deck paving and municipal road maintenance projects, and has significant economic, social and environmental benefits.

[0107] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0108] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0109] The above provides a detailed description of a high-performance rubber asphalt mortar and its preparation method. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for preparing high-performance rubber asphalt mortar, characterized in that, The method includes: (1) Raw material selection: 70# base asphalt, 40-mesh expanded rubber powder, and limestone mineral powder are selected; the 40-mesh expanded rubber powder has a sieve residue ≤0.5%, a relative density of 1.10~1.30, a moisture content ≤0.0%, a metal content ≤0.006%, and a fiber content ≤0.01%; the limestone mineral powder has an apparent density ≥2.45g / cm³. 3 Hydrophilicity coefficient <1, content of particles smaller than 0.075mm: 70-100%; (2) Preparation of rubber asphalt: Heat the base asphalt to 180±5℃; add rubber powder and stir continuously for 30 min; transfer to a shearing machine and shear at 4000 rpm for 30 min; place in a 180℃ constant temperature box and stir for 60 min to obtain the finished rubber asphalt; (3) Preparation of rubber asphalt mortar: Heat the rubber asphalt to 180℃; add the pre-weighed limestone mineral powder, and control the filler-binder ratio at 0.65~1.25; stir thoroughly at 180℃ to form rubber asphalt mortar; (4) Construction temperature control: Based on the viscosity-temperature fitting equation lnη=a-bT, where the correlation coefficient R 2 ≥0.99, adjust the construction temperature according to the filler-binder ratio so that the mortar viscosity is 5~15Pa·s during construction; in the viscosity-temperature fitting equation, a is 8.0266~10.957 and b is 0.0419~0.0463.

2. The method according to claim 1, characterized in that, The amount of rubber powder is 20% of the mass of the base asphalt.

3. The method according to claim 2, characterized in that, The 40-mesh expanded rubber powder is prepared by heat treatment at a temperature of 100-120°C for 2-3 hours, with a thermal expansion rate ≥30%.

4. The method according to claim 1, characterized in that, The filler-binder ratio is 0.

95.

5. The method according to claim 4, characterized in that, The limestone powder has the following particle size distribution: ≤5% of particles with a diameter of 0.075–0.15 mm, ≥60% of particles with a diameter of 0.038–0.075 mm, and ≥35% of particles with a diameter <0.038 mm.

6. The method according to claim 1, characterized in that, The construction temperature is 160-170℃, and a real-time temperature monitoring device is used during the construction process to control the temperature fluctuation range within ±3℃.

7. The method according to claim 1, characterized in that, When the filler-binder ratio is 0.65 to 0.95, the construction temperature is 160 to 170℃; when the filler-binder ratio is 1.0 to 1.25, the construction temperature is 170 to 180℃.

8. The preparation method according to claim 1, characterized in that, The process of thoroughly mixing at 180°C to form rubber asphalt mortar includes: using mechanical mixing at 180°C with a mixing speed of 500-800 rpm and a mixing time of 8-12 minutes to ensure that the mineral powder and rubber asphalt do not agglomerate and are thoroughly mixed to form rubber asphalt mortar.

9. The preparation method according to claim 1, characterized in that, The preparation of the rubber asphalt also includes a compatibility test, with the test standard being: after standing at 25°C for 48 hours, there should be no stratification or sedimentation, and the viscosity difference between the upper and lower layers should be ≤10%.

10. A high-performance rubber asphalt mortar, characterized in that, Prepared by the preparation method according to any one of claims 1 to 10; The rubber asphalt mortar has a rutting factor G* / sinδ≥2.3kPa at 70℃, a creep stiffness S≤500MPa and a creep rate m≥0.3 at -12℃; a viscosity of 5~10Pa·s at 170℃, and a temperature sensitivity parameter b of 0.042~0.046.

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