Anti-rutting asphalt concrete and preparation method thereof

Abstract

The invention discloses anti-rut asphalt concrete and a preparation method thereof, and belongs to the technical field of building materials used in road engineering, the anti-rut asphalt concrete is prepared from the following raw materials by weight: 50-60 parts of coarse aggregate, 34-40 parts of fine aggregate, 3-8 parts of cement, 0.2-0.5 part of a cellulose stabilizer and 4.5-5.5 parts of matrix asphalt, wherein the weight ratio of the coarse aggregate to the fine aggregate is (1.4-1.65): 1. According to the anti-rut asphalt concrete, a three-in-one anti-rut mechanism is formed through a high-proportion coarse skeleton embedding and extruding structure, cement composite adhesive cement hardening and cellulose space constraint; the anti-rutting concrete prepared from modified asphalt has the advantages that the same performance can be achieved only through the innovative proportion and physical action of conventional materials, the stability under long-term aging and extreme temperature is better, and compared with anti-rutting concrete prepared from modified asphalt, the concrete can reduce the cost by more than 25 yuan / ton, and has good economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials used in road engineering, and particularly relates to rutting-resistant asphalt concrete and a preparation method thereof. Background Art

[0002] Asphalt concrete, commonly known as asphalt concrete, is a mixture of artificially selected mineral materials with a certain graded composition, such as crushed stone or crushed gravel, stone chips or sand, mineral powder, etc., and a certain proportion of road asphalt materials, mixed under strictly controlled conditions. According to the different binders used, it can be divided into two categories: petroleum asphalt and coal asphalt. There are also those mixed with or blended with natural asphalt. According to the type of aggregate used, it can be divided into several categories: crushed stone, gravel, sandy, and slag. Crushed stone is the most commonly used.

[0003] Rutting is a permanent deformation produced on the wheel track of the driving lane, consisting of the depression in the wheel track and the ridges on both sides. The appearance of rutting seriously affects the service life and service quality of the road surface. The most serious problem at present is that when the high-temperature stability of the asphalt mixture is insufficient, especially when the temperature is above 50°C, the asphalt is prone to melting or softening. Under the action of wheel load, the internal material of the asphalt pavement structure layer produces lateral displacement due to flow, forming depressions in the wheel track.

[0004] Rutting poses numerous hazards to road surfaces and road users, severely impacting high-speed driving safety. Vehicles can easily lose control when changing direction, impacting driving stability. Currently, the most common preventative technical measure is to use coarser aggregate gradations. However, there is a conflict between rutting resistance and water stability. Coarsening gradations may improve rutting resistance, but it can also lead to segregation and a high residual void ratio, which can cause water seepage and damage.

[0005] Currently, existing technologies report addressing the rutting problem of asphalt pavements by adding high-molecular-weight polymers such as anti-rutting agents, anti-stripping agents, or phase change materials to improve the high-temperature stability of asphalt concrete. For example, CN 117447128 A discloses a high-strength, anti-rutting asphalt concrete and its preparation method. The disclosed high-strength, anti-rutting asphalt concrete is made from the following raw materials by weight: 6-10 parts cement, 65-85 parts coarse aggregate, 19-23 parts fine aggregate, 18-27 parts modified asphalt, 2-5 parts fiber, 0.4-0.7 parts anti-rutting agent, 3-4 parts epoxy resin, and 3-4 parts curing agent. While the modification effect is relatively good, the high-strength, anti-rutting asphalt concrete requires the use of modified asphalt and anti-rutting agents, resulting in high production costs and hindering its widespread application.

[0006] Therefore, it is necessary to optimize the raw material ratio and production process of existing asphalt concrete, so as to achieve low-cost improvement of the anti-rutting performance of asphalt concrete. Summary of the Invention

[0007] The object of the present invention is to provide a rutting-resistant asphalt concrete with a simple preparation process and low cost, and a preparation method of the asphalt concrete, so as to solve the problems raised in the above background technology.

[0008] The technical solution adopted by the present invention to solve the technical problem is: A rutting-resistant asphalt concrete is prepared from the following raw materials in parts by weight: 50-60 parts of coarse aggregate, 34-40 parts of fine aggregate, 3-8 parts of cement, 0.2-0.5 parts of cellulose stabilizer and 4.5-5.5 parts of matrix asphalt, wherein the weight ratio of the coarse aggregate to the fine aggregate is 1.4-1.65:1.

[0009] The rutting-resistant asphalt concrete of the present invention adopts a coarse aggregate and a fine aggregate with a weight ratio of 1.4-1.65:1 to construct a high-strength skeleton, wherein the coarse aggregate dominates the dense skeleton embedded structure, and the fine aggregate fills the gaps in the coarse skeleton, thereby improving the density and the concrete's resistance to shear deformation and reducing the porosity. The internal friction generated by the direct contact between the coarse aggregate and the fine aggregate particles significantly improves the concrete's resistance to deformation and anti-rutting performance; if the ratio of coarse aggregate to fine aggregate is lower than 1.4:1, the coarse aggregate cannot provide strong support to the surface layer, resulting in the fine aggregate being unable to better form a support network with the coarse aggregate, and if the proportion of fine aggregate is too high, the porosity of the asphalt concrete will be too small to meet the thermal expansion of the asphalt, and oil-type rutting will be easily formed; and if the ratio of coarse aggregate to fine aggregate is higher If the weight ratio of coarse aggregate to fine aggregate is higher than 1.65:1, the fine aggregate cannot be well filled between the coarse aggregate due to the excess coarse aggregate, resulting in a large porosity of the asphalt concrete and causing the asphalt concrete to deform under heavy pressure. Therefore, the weight ratio of coarse aggregate to fine aggregate is controlled between 1.4-1.65:1, which is conducive to the asphalt concrete reaching a balanced state after mixing and compaction, which is dense and has slight gaps. The hydration and gelation of cement is conducive to the formation of an alkaline interface on the aggregate surface, thereby enhancing the adhesion between the aggregate and the base asphalt. The hydration products of cement form a micro-skeleton in the asphalt mortar, and cellulose stabilizers such as wood fiber powder absorb water and swell to form microfiber bundles, which can penetrate into the mixture and form a three-dimensional network, thereby limiting the lateral flow of aggregate and further promoting the anti-rutting effect of asphalt concrete.

[0010] Secondly, the rutting-resistant asphalt concrete of the present invention uses concrete raw materials with wide sources and low costs to replace high molecular polymers such as anti-rutting agents, anti-stripping agents or phase change materials in existing rutting-resistant asphalt concrete, thereby reducing the production cost of asphalt concrete.

[0011] The coarse aggregate is composed of stones with a particle size of 5-10 mm, and the fine aggregate is composed of stone chips with a particle size of ≤3 mm and stones with a particle size of 3-5 mm in a weight ratio of 2-2.2:1.

[0012] In a certain exemplary embodiment, the 3-5mm stones are stones with a particle size of 3mm, and the 5-10mm stones are a mixture of stones with a particle size of 5mm and 10mm, and the weight ratio of the stones with a particle size of 5mm to 10mm is 4-6:1.

[0013] Preferably, an anti-rutting asphalt concrete is made from the following raw materials in parts by weight: 20-27 parts of stone chips, 10-18 parts of 3-5mm fine aggregate, 40-50 parts of 5mm coarse aggregate, 8-15 parts of 10mm coarse aggregate, 3-6 parts of cement, 0.2-0.3 parts of cellulose stabilizer and 4.8-5.1 parts of matrix asphalt.

[0014] In an exemplary embodiment, an anti-rutting asphalt concrete is made from the following raw materials in parts by weight: 22 parts stone chips, 16 parts 3-5 mm fine aggregate, 48 parts 5 mm coarse aggregate, 10 parts 10 mm coarse aggregate, 4 parts cement, 0.3 parts cellulose stabilizer, and 5.0 parts base asphalt.

[0015] Preferably, the cement is ordinary Portland 425 cement, the cellulose stabilizer is wood fiber powder or basalt mineral fiber powder, and the matrix asphalt is No. 70 asphalt.

[0016] Preferably, the rutting-resistant asphalt concrete has a thickness of 4 cm or less. If the asphalt concrete is too thick (greater than 4 cm), the coarse aggregate in the surface layer will not provide adequate support for the asphalt concrete. Instead, the asphalt concrete may collapse due to insufficient support strength, leading to rutting.

[0017] In a certain exemplary embodiment, the anti-rutting asphalt concrete base layer is made of AC25 asphalt concrete, and the maximum nominal particle size of the AC25 asphalt concrete is 26.5 cm.

[0018] The present invention further adopts the following technical solutions to solve the technical problems: A method for preparing rutting-resistant asphalt concrete comprises the following steps: S1. Dry and preheat the coarse aggregate and fine aggregate to 160-170℃ respectively, and sieve them for later use; S2. Add the spare aggregate in S1 to the asphalt mixture mixing tank in proportion, then add cement and cellulose stabilizer in proportion, and dry mix for 10-12 seconds; S3. Heat the base asphalt to 150-160℃ and add it into the asphalt mixture mixing tank, stirring and mixing for 30s-42s until the mixing tank discharge door automatically opens and the material is directly discharged to the transport vehicle.

[0019] The specific operation of S1 is as follows: the coarse aggregate and fine aggregate are screened according to grade, and then sent into the air drying drum through the conveyor belt and the cold aggregate elevator in sequence, and the aggregate is heated to 160-180°C. Then, the aggregate is transported to the vibrating screen through the hot aggregate elevator for screening and then enters the hot material bin for storage for standby.

[0020] S2. The aggregate is added into the asphalt mixture mixing tank in proportion through a hot aggregate weighing system.

[0021] Compared with the prior art, the present invention has the following beneficial effects: This rutting-resistant asphalt concrete forms a "trinity" anti-rutting mechanism through a high-proportion coarse skeleton embedded structure (anti-deformation basis) + cement composite mortar hardening (improving adhesion and stiffness) + cellulose spatial constraint (inhibiting fluidity); it does not rely on polymer modification or chemical additives, and can achieve the same performance only through the innovative proportions and physical effects of conventional materials, and has better stability under long-term aging and extreme temperatures, overcoming the technical prejudice of technicians in the existing technology that to solve the rutting of asphalt concrete at high temperatures, it is necessary to add anti-rutting agents or modify the asphalt.

[0022] Compared with rutting-resistant concrete prepared with modified asphalt, the cost of this rutting-resistant asphalt concrete has been significantly reduced. On average, the cost per ton of concrete can be reduced by more than 25 yuan / ton, and the construction cost of asphalt concrete roads can be reduced by more than 8%, which has significant economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a process flow chart of the method for preparing the rutting-resistant asphalt concrete of the present invention; Figure 2 This is a sample diagram of the anti-rutting asphalt concrete sample taken for Marshall test in Example 1 of the present invention; Figure 3 This is a real picture of the asphalt concrete pavement after the rutting-resistant asphalt concrete is constructed and formed according to Example 1 of the present invention; Figure 4 This is a sample diagram of the Marshall test of the rutting-resistant asphalt concrete sampled in Example 3 of the present invention. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] Comparative Example 1 The rutting-resistant asphalt concrete of this embodiment is made of the following raw materials in parts by weight: 1 part of stone chips, 42 parts of 3mm fine aggregate, 24 parts of 5mm coarse aggregate, 33 parts of 10mm coarse aggregate and 5.0 parts of matrix asphalt, wherein the weight ratio of coarse aggregate to fine aggregate is 1.326:1.

[0026] The rutting-resistant asphalt concrete of this embodiment passed the Marshall test. However, the rutting test results of the asphalt concrete (samples were sent to Zhongda Intelligent Technology Co., Ltd.) are shown in Table 1 below. Its dynamic stability is 1212 times / min and its CV is 12.6%. Although it meets the national product standards, it cannot meet the requirements of the road administration department for high-strength rutting-resistant asphalt concrete.

[0027] Table 1 Rutting test results

[0028] Note: 1. Specimen size: 300x300x50mm; 2. Specifications require that dynamic stability should be no less than 1000 times / mm.

[0029] Example 1 See also Figures 1 to 3 The rutting-resistant asphalt concrete of this embodiment is made of the following raw materials in parts by weight: 22 parts of stone chips, 16 parts of 3mm fine aggregate, 48 parts of 5mm coarse aggregate, 10 parts of 10mm coarse aggregate, 4 parts of cement, 0.3 parts of cellulose stabilizer and 5.0 parts of matrix asphalt, wherein the weight ratio of coarse aggregate to fine aggregate is 1.526:1.

[0030] The cement is ordinary silicate 425 cement, the cellulose stabilizer is wood fiber powder, and the matrix asphalt is No. 70 asphalt.

[0031] The thickness of the anti-rutting asphalt concrete is 4 cm.

[0032] The bottom layer of the anti-rutting asphalt concrete is made of AC25 asphalt concrete, and the maximum nominal particle size of the AC25 asphalt concrete is 26.5 cm.

[0033] The rutting-resistant asphalt concrete of this embodiment solidifies the AC13 mixture and lowers the softening point of the asphalt, preventing rutting and deformation under high temperatures and heavy loads. This "rigid-flexible" asphalt composite improves rutting resistance while retaining the AC13 mixture's excellent resistance to water damage, low-temperature cracking, fatigue, and scattering. This significantly increases the bearing capacity of the asphalt pavement, maintaining rutting depth indicators above good throughout its design life, and effectively addresses rutting-prone areas such as overloaded sections and intersections. Furthermore, it improves the pavement's skid resistance, comfort, and safety, reduces production and maintenance costs, and extends the life of the highway.

[0034] A method for preparing rutting-resistant asphalt concrete according to the present embodiment comprises the following steps: S1. Dry and preheat the coarse aggregate and fine aggregate to 160-170℃ respectively, and sieve them for later use; S2. Add the spare aggregate in S1 to the asphalt mixture mixing tank in proportion through the hot aggregate weighing system, then add cement and cellulose stabilizer in proportion, and dry mix for 10 seconds; S3. Heat the base asphalt to 150-160℃ and add it into the asphalt mixture mixing tank, stirring and mixing for 40 seconds until the mixing tank discharge door automatically opens and the material is directly discharged to the transport vehicle.

[0035] The specific operation of S1 is as follows: the coarse aggregate and fine aggregate are screened according to grade, and then sent into the air drying drum through the conveyor belt and the cold aggregate elevator in sequence, and the aggregate is heated to 160-180°C. Then, the aggregate is transported to the vibrating screen through the hot aggregate elevator for screening and then enters the hot material bin for storage for standby.

[0036] A rutting-resistant asphalt concrete of this embodiment was subjected to a Marshall test. The specific conditions were: experimental temperature 168 degrees, mixture weight 1200±5 grams, compaction times 75 times each, specimen specifications: diameter 101.6 mm, height 63.5 mm, density 2.40, and the experimental results were qualified.

[0037] The results of the rutting test of the asphalt concrete of this embodiment (samples were sent to Zhongda Intelligent Technology Co., Ltd.) are shown in Table 2 below. Its dynamic stability is 2906 times / min and CV is 1.5%. Compared with the asphalt concrete of the comparative example, its dynamic stability in the rutting test is significantly improved.

[0038] Table 2 Rutting test results

[0039] Note: 1. Specimen size: 300x300x50mm; 2. Specifications require that dynamic stability should be no less than 1000 times / mm.

[0040] The cost comparison analysis of the AC-13 asphalt concrete produced in this embodiment and the AC-13 asphalt concrete produced by the traditional process is shown in Table 3 below.

[0041] Table 3 Cost comparison of AC-13 asphalt concrete obtained with two different ingredients and production processes

[0042] As can be seen from Table 1 above, the performance of the rutting-resistant asphalt concrete of the present invention is comparable to that of the AC-13 asphalt concrete originally used by the applicant, but its cost is reduced by RMB 25.41 per ton. Since the amount of asphalt concrete used in highway construction is large, if a road 500 meters long and 3.5 meters wide is paved with 4 cm thick asphalt concrete, approximately 161 tons of AC-13 are required. The cost of the new process is RMB 44,806.3, while the cost of the traditional process is RMB 48,897.31. The new process saves RMB 4,091.01 compared to the traditional process. If a road 500 meters long and 14 meters wide is paved with 4 cm thick asphalt concrete, approximately 644 tons of AC-13 are required. The cost of the new process is RMB 179,225.2, while the cost of the traditional process is RMB 195,589.24. The new process saves RMB 16,364.04 compared to the traditional process. When the cost per ton of asphalt concrete is reduced by as much as 8.37% compared to the traditional process, the economic benefit is extremely significant.

[0043] Example 2 See also Figure 1 The rutting-resistant asphalt concrete of this embodiment is made of the following raw materials in parts by weight: 20 parts of stone chips, 16 parts of 3mm fine aggregate, 48 parts of 5mm coarse aggregate, 10 parts of 10mm coarse aggregate, 4 parts of cement, 0.3 parts of cellulose stabilizer and 5.0 parts of matrix asphalt, wherein the weight ratio of coarse aggregate to fine aggregate is 1.61:1.

[0044] The cement is ordinary silicate 425 cement, the cellulose stabilizer is wood fiber powder, and the matrix asphalt is No. 70 asphalt.

[0045] The thickness of the anti-rutting asphalt concrete is 4 cm.

[0046] The bottom layer of the anti-rutting asphalt concrete is made of AC25 asphalt concrete, and the maximum nominal particle size of the AC25 asphalt concrete is 26.5 cm.

[0047] The preparation method of the rutting-resistant asphalt concrete in this embodiment is the same as that in Example 1. The concrete sample is subjected to the Marshall test. The specific conditions are: experimental temperature 168 degrees, mixture weight 1200 grams, compaction number 75 times, specimen specifications: diameter 101.6 mm, height 64.1 mm, density 2.38, and experimental results: qualified.

[0048] The results of the rutting test of the asphalt concrete of this embodiment (samples were sent to Zhongda Intelligent Technology Co., Ltd.) are shown in Table 4 below. Its dynamic stability is 4242 times / min and CV is 2.6%. Compared with the asphalt concrete of Comparative Example 1, its dynamic stability in the rutting test is significantly improved.

[0049] Table 4 Rutting test results

[0050] Note: 1. Specimen size: 300x300x50mm; 2. Specifications require that dynamic stability should be no less than 1000 times / mm.

[0051] The production cost of the rutting-resistant asphalt concrete of this embodiment is 276.94 yuan / ton, which is 26.77 yuan / ton lower than the production cost of the traditional AC-13 asphalt concrete, and has good economic benefits.

[0052] Example 3 See also Figure 1 The rutting-resistant asphalt concrete of this embodiment has the following differences compared with Example 1: A rutting-resistant asphalt concrete is made from the following raw materials in parts by weight: 22 parts of stone chips, 15 parts of 3mm fine aggregate, 47 parts of 5mm coarse aggregate, 8 parts of 10mm coarse aggregate, 4 parts of cement, 0.3 parts of cellulose stabilizer and 5.0 parts of matrix asphalt, wherein the weight ratio of coarse aggregate to fine aggregate is 1.486:1.

[0053] The preparation method of the rutting-resistant asphalt concrete of this embodiment is the same as that of Example 1. The concrete sample is subjected to the Marshall test. The specific conditions are: experimental temperature 170 degrees, mixture weight 1200 grams, compaction times 75 times, specimen specifications: diameter 101.6 mm, height 64 mm, density 2.38, and the actual Marshall test sample is as follows: Figure 4 As shown, the experimental results are qualified.

[0054] The production cost of the rutting-resistant asphalt concrete of this embodiment is 275.48 yuan / ton, which is 28.23 yuan / ton lower than the production cost of the traditional AC-13 asphalt concrete, significantly reducing the construction cost and having great economic benefits.

[0055] After the applicant successfully researched and developed the rutting-resistant asphalt concrete of the present invention, it has been paved and verified in actual use in many municipal projects in Ningxiang, Hunan Province, including the Weidong Avenue construction site (constructed in July 2024, using the rutting-resistant asphalt concrete described in Example 3), Changjun Road project, Yanjiang Road project (October 2024, using the rutting-resistant asphalt concrete described in Example 2), and Tianyi Medical construction site (constructed in July 2025, using the rutting-resistant asphalt concrete described in Example 1). No rutting has occurred on the roads constructed above so far, which completely solves the problem that rutting is easily formed at high temperatures in conventional asphalt concrete.

[0056] The above description only describes the features of some embodiments of the present invention and does not limit the scope of protection of the present invention. Any modification or deformation that may be made using the technical content disclosed by the present invention still falls within the scope of protection of the present invention.

Claims

1. A rutting-resistant asphalt concrete, characterized by: The invention is prepared from the following raw materials in parts by weight: 50-60 parts of coarse aggregate, 34-40 parts of fine aggregate, 3-8 parts of cement, 0.2-0.5 parts of cellulose stabilizer and 4.5-5.5 parts of matrix asphalt, wherein the weight ratio of coarse aggregate to fine aggregate is 1.4-1.65:

1.

2. The rutting-resistant asphalt concrete according to claim 1, wherein: The coarse aggregate is composed of stones with a particle size of 5-10 mm, and the fine aggregate is composed of stone chips with a particle size of ≤3 mm and stones with a particle size of 3-5 mm in a weight ratio of 2-2.2:

1.

3. The rutting-resistant asphalt concrete according to claim 2, characterized in that: The 3-5mm stones are stones with a particle size of 3mm, and the 5-10mm stones are a mixture of stones with a particle size of 5mm and 10mm, and the weight ratio of the stones with a particle size of 5mm to 10mm is 4-6:

1.

4. The rutting-resistant asphalt concrete according to claim 1, wherein: The rutting-resistant asphalt concrete is made of the following raw materials in parts by weight: 22 parts of stone chips, 16 parts of 3-5 mm fine aggregate, 48 parts of 5 mm coarse aggregate, 10 parts of 10 mm coarse aggregate, 4 parts of cement, 0.3 parts of cellulose stabilizer and 5.0 parts of base asphalt.

5. The rutting-resistant asphalt concrete according to claim 2, wherein: The cement is ordinary silicate 425 cement, the cellulose stabilizer is wood fiber powder or basalt mineral fiber powder, and the matrix asphalt is No. 70 asphalt.

6. The rutting-resistant asphalt concrete according to claim 1, wherein: The surface layer thickness of the rutting-resistant asphalt concrete is ≤4 cm.

7. The rutting-resistant asphalt concrete according to any one of claims 1 to 6, characterized in that: The bottom layer of the anti-rutting asphalt concrete adopts AC25 asphalt concrete.

8. A method for preparing rutting-resistant asphalt concrete, characterized by: The following steps are involved: S1. Dry and preheat the coarse aggregate and fine aggregate to 160-170℃ respectively, and sieve them for later use; S2. Add the spare aggregate in S1 to the asphalt mixture mixing tank in proportion, then add cement and cellulose stabilizer in proportion, and dry mix for 10-12 seconds; S3. Heat the base asphalt to 150-160℃ and add it into the asphalt mixture mixing tank, stirring and mixing for 30s-42s until the mixing tank discharge door automatically opens and the material is directly discharged to the transport vehicle.

9. The method for preparing rutting-resistant asphalt concrete according to claim 8, wherein: The specific operation of S1 is as follows: the coarse aggregate and fine aggregate are screened according to grade, and then sent into the air drying drum through the conveyor belt and the cold aggregate elevator in sequence, and the aggregate is heated to 160-180°C. Then, the aggregate is transported to the vibrating screen through the hot aggregate elevator for screening and then enters the hot material bin for storage for standby.

10. The method for preparing rutting-resistant asphalt concrete according to claim 8, wherein: S2. The aggregate is added into the asphalt mixture mixing tank in proportion through a hot aggregate weighing system.

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