A noise-reducing asphalt pavement structure

Abstract

The present invention belongs to the field of asphalt pavements, and particularly relates to a noise-reducing asphalt pavement structure, which includes a semi-open-graded modified asphalt mixture surface course. The void ratio of the semi-open-graded modified asphalt mixture surface course is 7% - 10%; the gradation of the semi-open-graded modified asphalt mixture surface course is SMA-10. In the pavement structure proposed in this application, the surface course is an SMA-10 semi-open-graded modified asphalt mixture with a void ratio of 7 - 10%. There are certain open pores retained on the surface of the surface course, and most of the internal pores are closed pores. Compared with a porous asphalt pavement with a void ratio of about 20%, when using a semi-open-graded modified asphalt mixture surface course with a void ratio of 7 - 10%, dust and other sundries are not easily introduced into the interior of the asphalt mixture, the pores of the asphalt mixture are not easily blocked, the noise reduction effect is more durable than that of a conventional porous asphalt pavement structure, and the structural performance is stable.

Description

Technical Field

[0001] The present invention belongs to the technical field of asphalt pavement, and particularly relates to a noise-reducing asphalt pavement structure. Background Art

[0002] Road vehicles generate noise during operation. The methods for controlling traffic noise generally start from three aspects: the noise source, the channel along the road, and the receiving end. For the frictional noise generated by the contact between the tire and the road surface (tire noise), from the aspect of the road surface, a noise-reducing pavement can be used to reduce tire noise. Existing noise-reducing pavements usually include: (1) porous asphalt pavement; (2) fine-aggregate asphalt pavement; (3) rubber asphalt pavement.

[0003] The surface layer of the porous asphalt pavement is mostly fine-grained drainage asphalt concrete (such as PAC-13) and open-graded friction course (such as OGFC-13), and its void ratio is as high as 15% - 20%, or even exceeds 20%. Due to the large void ratio, the noise generated by the tire during driving on the road surface can be reduced. However, at the same time, due to the large void ratio, rainwater and the soil it carries can penetrate into the road surface, and it is prone to blockage during long-term service and is difficult to handle, resulting in general noise reduction durability; and due to the relatively large void ratio, the density of asphalt and aggregates is lower than that of the dense-graded asphalt pavement, and the durability is poor.

[0004] Therefore, there is an urgent need for a new pavement structure to solve the problem of easy blockage of the existing porous asphalt pavement. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a noise-reducing asphalt pavement structure, aiming to solve the problem of easy blockage of the existing porous asphalt pavement and improve the durability of the noise reduction effect of the pavement structure at the same time.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A noise-reducing asphalt pavement structure includes a semi-open-graded modified asphalt mixture surface layer, and the void ratio of the semi-open-graded modified asphalt mixture surface layer is 7% - 10%; the gradation of the semi-open-graded modified asphalt mixture surface layer is SMA-10, and its raw materials include the following components in parts by mass:

[0008] 5.8% - 6.0% of asphalt, 90% - 91.2% of mineral materials, 2% - 3% of mineral powder, 0.3% - 0.5% of lignin fiber, and the total mass of the raw materials meets 100%.

[0009] Further, the noise-reducing asphalt pavement structure includes, from top to bottom, the semi-open-graded modified asphalt mixture surface course, the first modified emulsified asphalt tack coat, the dense-graded modified asphalt mixture middle course, the second modified emulsified asphalt tack coat, the dense-graded asphalt mixture bottom course, the synchronous chip seal, the cement stabilized macadam base course, and the cement stabilized macadam sub-base course.

[0010] Further, the first modified emulsified asphalt tack coat and the second modified emulsified asphalt tack coat have the same composition, and the first modified emulsified asphalt tack coat is all SBS modified emulsified asphalt.

[0011] Further, the gradation of the dense-graded modified asphalt mixture middle course is AC-20C, and its raw materials include the following components by mass fraction:

[0012] 3.9% - 4.1% asphalt, 94.5% - 95.5% mineral aggregate, 0.8% - 1% mineral powder, and the total mass of the raw materials meets 100%.

[0013] Further, the gradation of the dense-graded asphalt mixture bottom course is AC-25C, and its raw materials include the following components by mass fraction:

[0014] 3.5% - 3.7% asphalt, 95.5% - 96.5% mineral aggregate, 0.5% - 0.8% mineral powder, and the total mass of the raw materials meets 100%.

[0015] Further, the synchronous chip seal is an SBS modified asphalt synchronous chip seal, the dosage of SBS modified asphalt is 2.0 - 2.4 kg / m 2 , 60 - 70% of the crushed stones are evenly spread, the spreading amount of the crushed stones is 9 - 11 m per 1000 square meters 3 , and the particle size of the crushed stones is 13.2 - 19 mm.

[0016] Further, the cement stabilized macadam base course adopts skeleton dense type cement stabilized macadam, and its raw materials are cement, crushed stones and water, the mass ratio of cement to crushed stones = 5%, and the strength is 5.0 - 7.0 MPa.

[0017] Further, the cement stabilized macadam sub-base course adopts skeleton dense type cement stabilized macadam, and its raw materials are cement, crushed stones and water, the mass ratio of cement to crushed stones = 4%, and the strength is 3.0 - 5.0 MPa.

[0018] Further, the thickness of the semi-open-graded modified asphalt mixture surface course is 2 - 3 cm, and the dosages of the first modified emulsified asphalt tack coat and the second modified emulsified asphalt tack coat are 0.4 - 0.6 L / m 2, the thickness of the intermediate layer of the dense-graded modified asphalt mixture is 6 - 8 cm, the thickness of the bottom layer of the dense-graded asphalt mixture is 8 - 10 cm, the thickness of the synchronous chip seal is 0.5 - 1 cm, the thickness of the cement stabilized macadam base course is 36 - 40 cm, and the thickness of the cement stabilized macadam sub-base course is 20 - 25 cm.

[0019] Further, the thickness of the upper layer of the semi-open-graded modified asphalt mixture is 3 cm, and the application amounts of the first modified emulsified asphalt tack coat and the second modified emulsified asphalt tack coat are 0.5 L / m 2 , the thickness of the intermediate layer of the dense-graded modified asphalt mixture is 6 cm, the thickness of the bottom layer of the dense-graded modified asphalt mixture is 8 cm, the thickness of the synchronous chip seal is 1 cm, the thickness of the cement stabilized macadam base course is 36 cm, and the thickness of the cement stabilized macadam sub-base course is 20 cm.

[0020] For the function of noise reduction of asphalt pavement, it has not been widely concerned before. PAC (permeable asphalt concrete) or OGFC (open-graded friction course) asphalt pavement has the function of drainage and noise reduction, but its main purpose is to solve the problem of road surface drainage and improve the skid resistance of the road surface, and the noise reduction performance is its subsidiary function. In recent years, with the increase in the number of cars and the attention to the quality of urban life, the noise reduction function of the road surface has been widely concerned. PAC or OGFC pavement with a void ratio of 15 - 20% does have good noise reduction effect in the short term, but its easy clogging problem makes its noise reduction effect not persistent, and its road performance will also be reduced. By adopting the road surface structure proposed in this application, the void ratio of the upper layer is appropriately reduced, making the noise reduction effect more persistent. And compared with the road surface with a void ratio of 20% or so, the road surface structure proposed in this application has better compactness, and in terms of road performance, it is also more superior.

[0021] The beneficial effects of the present invention are:

[0022] In the road surface structure proposed in this application, the upper layer is SMA-10 semi-open-graded modified asphalt mixture with a void ratio of 7 - 10%. There are certain open pores on the surface of the road surface structure layer, and most of the internal pores are closed pores. The open pores consume part of the energy of the sound. After the sound wave passes through the open pores and enters the closed pores, the sound energy is repeatedly refracted and consumed in the closed pores, so as to achieve a better noise reduction effect. And compared with the porous asphalt pavement with a void ratio of about 20%, when using the SMA-10 semi-open-graded modified asphalt mixture surface layer with a void ratio of 7 - 10%, dust and other sundries are not easy to enter the interior of the asphalt mixture, and the pores of the asphalt mixture are not easy to clog, and the noise reduction effect is more persistent than that of the conventional porous asphalt pavement structure, and the structural performance is stable. Description of the Drawings

[0023] The accompanying drawings of the specification, which form a part of the present application, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

[0024] Figure 1 It is a schematic diagram of the pavement structure of an embodiment of the present invention.

[0025] In the figure: open-graded modified asphalt mixture surface course - 1, modified emulsified asphalt tack coat - 2, dense-graded modified asphalt mixture intermediate course - 3, second modified emulsified asphalt tack coat - 4, dense-graded asphalt mixture bottom course - 5, synchronous chip seal - 6, cement stabilized macadam base course - 7, cement stabilized macadam subbase course - 8. Detailed implementation manners

[0026] Next, the technical solutions in the embodiments of the present invention will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0027] Next, the present invention will be described in detail with reference to the accompanying drawings and in combination with embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0028] As Figure 1 shown, a noise-reducing asphalt pavement structure includes, from top to bottom, the open-graded modified asphalt mixture surface course 1, the first modified emulsified asphalt tack coat 2, the dense-graded modified asphalt mixture intermediate course 3, the second modified emulsified asphalt tack coat 4, the dense-graded asphalt mixture bottom course 5, the synchronous chip seal 6, the cement stabilized macadam base course 7, and the cement stabilized macadam subbase course 8;

[0029] The void ratio of the open-graded modified asphalt mixture surface course 1 is 7% - 10%; the gradation of the open-graded modified asphalt mixture surface course 1 is SMA-10, and its raw materials include the following components in parts by mass:

[0030] 5.8% - 6.0% of asphalt, 90% - 91.2% of mineral aggregate, 2% - 3% of mineral powder, 0.3% - 0.5% of lignin fiber, and the total mass of the raw materials meets 100%.

[0031] The first modified emulsified asphalt tack coat 2 and the second modified emulsified asphalt tack coat 4 have the same composition, and the first modified emulsified asphalt tack coat 2 is all SBS modified emulsified asphalt. SBS modified emulsified asphalt is a mature commercially available product, and its performance meets JC / T975-2005 "Waterproof Coating for Road and Bridge" and JC / T408-2005 "Emulsion-Type Asphalt Waterproof Coating".

[0032] The grading of the intermediate layer of the dense-graded modified asphalt mixture is AC-20C, and its raw materials include the following components by mass fraction: 3.9% - 4.1% asphalt, 94.5% - 95.5% mineral aggregate, and 0.8% - 1% mineral powder. The total mass of the raw materials meets 100%.

[0033] The grading of the lower layer of the dense-graded asphalt mixture is AC-25C, and its raw materials include the following components by mass fraction: 3.5% - 3.7% asphalt, 95.5% - 96.5% mineral aggregate, and 0.5% - 0.8% mineral powder. The total mass of the raw materials meets 100%.

[0034] The synchronous chip seal 6 is an SBS modified asphalt synchronous chip seal 6, with the SBS modified asphalt dosage of 2.0 - 2.4 kg / m 2 , and 60 - 70% of the chips are evenly spread, with the chip spreading amount of 9 - 11 m per 1000 square meters 3 , and the chip particle size is 13.2 - 19 mm.

[0035] The cement content of the cement stabilized macadam base course 7 is 5% (cement mass / macadam mass); the maximum aggregate size shall not exceed 31.5 mm, and the mass percentage of the component with a size ≥ 5 mm shall not be less than 60%; when the fine-grained soil below 0.5 mm in the aggregate has a plastic index, the particle content less than 0.075 mm shall not exceed 3.5%, and when the fine-grained soil below 0.5 mm in the aggregate has no plastic index, the particle content less than 0.075 mm shall not exceed 5%. The test specimens are made by the vibration forming method using the raw materials of the cement stabilized macadam base course 7, and the representative value of the specimen strength is 5.0 - 7.0 MPa.

[0036] The cement content of the cement stabilized macadam sub-base course 8 is 4% (cement mass / macadam mass); the maximum aggregate size shall not exceed 31.5 mm, and the mass percentage of the component with a size ≥ 5 mm shall not be less than 50%; when the fine-grained soil below 0.5 mm in the aggregate has a plastic index, the particle content less than 0.075 m shall not exceed 5%, and when the fine-grained soil below 0.5 mm in the aggregate has no plastic index, the particle content less than 0.075 m shall not exceed 7%. The test specimens are made by the vibration forming method using the raw materials of the cement stabilized macadam base course 7, and the representative value of the specimen strength is 3.0 - 5.0 MPa. The aggregate gradings of the cement stabilized macadam base course 7 and the sub-base course are shown in Table 1.

[0037] Table 1 Aggregate gradings of cement stabilized macadam

[0038]

[0039] The biggest difference between the pavement structure proposed in this application and the traditional pavement structure lies in the upper layer. By setting a void ratio of 7% - 10%, on the basis of ensuring the noise reduction effect, the problem that the existing porous asphalt pavement is prone to blockage is solved, and the durability of the noise reduction effect is improved; at the same time, the combined action of each surface layer and the base enhances the pavement performance and service life, where:

[0040] The first modified emulsified asphalt tack coat 2 and the second modified emulsified asphalt tack coat 4 enhance the interlayer bonding force, ensure the tight combination between the upper layer, the middle layer and the lower layer, and form a continuous and stable structural system; at the same time, based on the waterproof performance of asphalt, it can prevent the water infiltrating from the upper surface layer from continuing to infiltrate and causing damage to the lower pavement layer;

[0041] The dense-graded modified asphalt mixture middle layer 3 is responsible for bearing the vehicle load, transmitting stress, and dispersing pressure. Its dense-graded design helps to reduce pavement deformation and improve the durability and smoothness of the pavement;

[0042] The dense-graded asphalt mixture lower layer 5 further enhances the bearing capacity and stability of the pavement. At the same time, as a transition layer between the pavement and the base, it helps to disperse the load borne by the base and reduce the deformation of the base;

[0043] The synchronous chip seal 6 has functions such as bonding and waterproofing, which can effectively improve the road service performance and extend the road service life; the synchronous chip seal 6 makes the dense-graded asphalt mixture lower layer 5 and the cement stabilized macadam base 7 closely combined, ensuring the stability and durability of the entire pavement structure, and preventing pavement damage caused by uneven settlement of the foundation;

[0044] The cement stabilized macadam base 7 and the cement stabilized macadam sub-base 8 provide a solid foundation for the entire pavement structure, with high strength and good water stability, which can ensure the stability of the pavement under various climatic conditions and prevent pavement settlement and uneven deformation.

[0045] Furthermore, the thickness of the semi-open-graded modified asphalt mixture upper layer 1 is 2 - 3 cm, the thickness of the dense-graded modified asphalt mixture middle layer 3 is 6 - 8 cm, the thickness of the dense-graded asphalt mixture lower layer 5 is 8 - 10 cm, the thickness of the synchronous chip seal 6 is 0.5 - 1 cm, the thickness of the cement stabilized macadam base 7 is 36 - 40 cm, and the thickness of the cement stabilized macadam sub-base 8 is 20 - 25 cm.

[0046] In a preferred embodiment, the thickness of the semi-open-graded modified asphalt mixture upper layer 1 is 3 cm, the thickness of the dense-graded modified asphalt mixture middle layer 3 is 6 cm, the thickness of the dense-graded asphalt mixture lower layer 5 is 8 cm, the thickness of the synchronous chip seal 6 is 1 cm, the thickness of the cement stabilized macadam base 7 is 36 cm, and the thickness of the cement stabilized macadam sub-base 8 is 20 cm.

[0047] According to the layer thickness of the preferred embodiment, a test road was paved and tested according to the conventional construction method. The test road paved by the invention is recorded as Example 1, and the upper layer was changed to obtain Comparative Example 1 and Comparative Example 2.

[0048] In Example 1, the raw material composition is 5.9% asphalt, 91.6% mineral aggregate, 2% mineral powder, and 0.5% lignin fiber, and the total mass of the raw materials is 100%; the void ratio is 8.2%, and the thickness is 3 cm; the asphalt used in the raw materials is high-viscosity asphalt, which needs to meet the requirements of the national standard of the People's Republic of China GB / T 30516-2014 "High Viscosity and High Elasticity Road Asphalt". The most important indicators need to meet: the dynamic viscosity (60 °C) is greater than 20,000 Pa·s, and the elastic recovery (25 °C) is greater than 85%. The mineral aggregate raw material used is basalt, and the mineral powder is obtained by grinding limestone.

[0049] The upper layer of Comparative Example 1 is PAC-13 drainage asphalt mixture, and its raw material composition is 4.2% SBS modified asphalt, 93.8% mineral aggregate, 2% mineral powder, and the total mass of the raw materials is 100%; the void ratio is 20.7%, and the thickness is 3 cm. Comparative Example 1 represents a traditional PAC-13 drainage asphalt pavement.

[0050] The upper layer of Comparative Example 2 is SMA-13 asphalt mastic mixture, and its raw material composition is 5.7% SBS modified asphalt, 91.9% mineral aggregate, 2% mineral powder, 0.4% lignin fiber, and the total mass of the raw materials is 100%; the void ratio is 3.6%, and the thickness is 3 cm. Comparative Example 2 represents a common SMA-13 asphalt pavement.

[0051] After paving the test road, the sound pressure level was measured for Example 1, Comparative Example 1 and Comparative Example 2 for 3 consecutive years by the trailer method (CPX method), the test speed was 70 km / h, and the test results are as follows:

[0052] Table 2 Noise test result table

[0053]

[0054] As can be seen from Table 2, Example 1 can maintain almost the same noise reduction effect as Comparative Example 1, but the noise reduction effect of Comparative Example 1 is not persistent. The sound pressure level increases in the third year, that is, the noise between the road surface and the tire increases, and the noise reduction effect is significantly reduced; while the noise reduction effect of Example 1 can still be maintained after 2 years, indicating that its noise reduction effect is more persistent than that of the conventional porous asphalt pavement structure.

[0055] According to the "Highway Technical Condition Evaluation Standard" (JTG 5210-2018), the rutting index, damage index, and structural strength index of Example 1, Comparative Example 1, and Comparative Example 2 in the past three years were evaluated. For these three indicators, the larger the value, the better the performance of the road section. It can be seen from the test results in Table 3 that from the perspective of road performance analysis, the road performance of Example 1 is close to that of Comparative Example 2, while the rutting index, damage index, and structural strength index of Comparative Example 1 decreased significantly in the third year. This shows that the road performance of Example 1 and Comparative Example 2 is relatively stable, and the road performance of Example 1 of the present invention can basically reach the level of Comparative Example 2.

[0056] Table 3 Road Performance Test Results Table

[0057]

[0058] Through comprehensive analysis of the noise reduction effect and road performance of Example 1, Comparative Example 1, and Comparative Example 2, it can be found that from the aspect of noise reduction effect analysis, the initial noise reduction effect of Example 1 is close to that of Comparative Example 1 (traditional PAC-13 porous asphalt pavement), and as time goes by, its noise reduction effect is more stable; from the aspect of road performance analysis, the road performance of Example 1 is close to that of Comparative Example 2 (common SMA-13 asphalt pavement), and compared with Comparative Example 1 (traditional PAC-13 porous asphalt pavement), the road performance is also more stable.

[0059] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A noise reduction asphalt pavement structure, characterized by: The invention comprises, from top to bottom, a semi-open graded modified asphalt mixture upper layer (1), a first modified emulsified asphalt tack coat (2), a dense graded modified asphalt mixture middle layer (3), a second modified emulsified asphalt tack coat (4), a dense graded asphalt mixture lower layer (5), a synchronous crushed stone seal coat (6), a cement stabilized crushed stone base layer (7) and a cement stabilized crushed stone subbase layer (8); the semi-open graded modified asphalt mixture upper layer (1) has a void ratio of 7% to 10%; the semi-open graded modified asphalt mixture upper layer (1) has a thickness of 2 to 3 cm; the semi-open graded modified asphalt mixture upper layer (1) has a gradation of SMA-10, and its raw materials include the following components in parts by weight: 5.8%~6.0% asphalt, 90%~91.2% mineral material, 2%~3% mineral powder, 0.3%~0.5% lignin fiber, the total mass of raw materials meets 100%.

2. The noise reduction asphalt pavement structure according to claim 1 is characterized in that: The first modified emulsified asphalt adhesive layer (2) and the second modified emulsified asphalt adhesive layer (4) have the same composition, and the first modified emulsified asphalt adhesive layer (2) is SBS modified emulsified asphalt.

3. The noise reduction asphalt pavement structure according to claim 1, characterized in that: The dense-graded modified asphalt mixture middle surface layer (3) is graded AC-20C, and its raw materials include the following components in parts by weight: 3.9%~4.1% asphalt, 94.5%~95.5% mineral material, 0.8%~1% mineral powder, the total mass of raw materials meets 100%.

4. The noise reduction asphalt pavement structure according to claim 1, characterized in that: The lower layer (5) of the dense-graded asphalt mixture has a grading of AC-25C, and its raw materials include the following components in parts by weight: 3.5%~3.7% asphalt, 95.5%~96.5% mineral material, 0.5%~0.8% mineral powder, the total mass of raw materials meets 100%.

5. The noise reduction asphalt pavement structure according to claim 1, characterized in that: The synchronous chip seal (6) is a SBS modified asphalt synchronous chip seal (6), and the amount of SBS modified asphalt is 2.0-2.4 kg / m 2 , spread 60~70% of the gravel, the amount of gravel spread is 9~11m per 1000 square meters 3 The particle size of the gravel is 13.2~19mm.

6. The noise reduction asphalt pavement structure according to claim 1, characterized in that: The cement-stabilized crushed stone base (7) uses skeleton-dense cement-stabilized crushed stone, whose raw material composition is cement, crushed stone and water, cement mass / crushed stone mass=5%, and strength is 5.0-7.0 MPa.

7. The noise reduction asphalt pavement structure according to claim 1, characterized in that: The cement-stabilized crushed stone subbase (8) uses skeleton-dense cement-stabilized crushed stone, whose raw material composition is cement, crushed stone and water, cement mass / crushed stone mass=4%, and strength is 3.0-5.0 MPa.

8. The noise reduction asphalt pavement structure according to claim 1, characterized in that: The dosage of the first modified emulsified asphalt adhesive layer (2) and the second modified emulsified asphalt adhesive layer (4) is 0.4-0.6 L / m 2 The thickness of the dense-graded modified asphalt mixture surface layer (3) is 6 to 8 cm, the thickness of the dense-graded asphalt mixture lower layer (5) is 8 to 10 cm, the thickness of the synchronous crushed stone seal layer (6) is 0.5 to 1 cm, the thickness of the cement-stabilized crushed stone base layer (7) is 36 to 40 cm, and the thickness of the cement-stabilized crushed stone subbase layer (8) is 20 to 25 cm.

9. The noise reduction asphalt pavement structure according to claim 1, characterized in that: The thickness of the upper layer (1) of the semi-open graded modified asphalt mixture is 3 cm, and the dosage of the first modified emulsified asphalt adhesive layer (2) and the second modified emulsified asphalt adhesive layer (4) is 0.5 L / m 2 The thickness of the dense-graded modified asphalt mixture surface layer (3) is 6 cm, the thickness of the dense-graded asphalt mixture lower layer (5) is 8 cm, the thickness of the synchronous crushed stone seal layer (6) is 1 cm, the thickness of the cement-stabilized crushed stone base layer (7) is 36 cm, and the thickness of the cement-stabilized crushed stone subbase layer (8) is 20 cm.

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