Design and construction method for crack-resistant heavy-duty traffic highway asphalt pavement

Abstract

The present invention relates to a design and construction method for a crack-resistant heavy-duty traffic highway asphalt pavement, belonging to the technical field of road engineering. It solves the problems of the disease of cracks in the existing highway asphalt pavement and the deficiencies in the pavement structure, and is particularly applicable to heavy-duty traffic grade highways. A design and construction method for a crack-resistant heavy-duty traffic highway asphalt pavement includes determining the pavement structure based on the bearing capacity of the pavement, which from top to bottom includes a surface wearing course, a high-modulus asphalt concrete layer, a base course, a sub-base course, etc.; then determining the construction sequence, including sequentially paving the sub-base course, the base course, a fiber crack-resistant modified asphalt waterproof bonding layer, the high-modulus asphalt concrete layer, and then paving an intermediate bonding layer and the surface wearing course, or directly paving the surface wearing course. It realizes the beneficial effects of improving the crack resistance performance of heavy-duty traffic highways, improving the bearing capacity, reducing the pavement thickness, and extending the service life.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering, and particularly relates to a design and construction method for a crack-resistant heavy-duty traffic highway asphalt pavement. Background Art

[0002] Asphalt pavements at home and abroad are all elastic layer structures, generally composed of surface layer, base layer, sub-base layer and cushion layer from top to bottom. The surface layer directly bears the action of vehicle loads and the influence of natural environmental factors, and is composed of 1 to 3 layers of asphalt concrete according to highway grades, traffic volumes and functional requirements; the base layer is arranged under the surface layer and together with the surface layer transfers vehicle loads to the sub-base layer, cushion layer and subgrade, and is the main structural layer that plays a load-bearing role in asphalt pavements; the sub-base layer is arranged under the base layer and together with the surface layer and base layer bears the action of vehicle loads, playing a secondary load-bearing role; the cushion layer is arranged between the sub-base layer and the subgrade, playing the roles of drainage, water isolation and frost prevention.

[0003] According to the different types and stiffnesses of base layer materials, asphalt pavements can be divided into four types: flexible base asphalt pavements, semi-rigid base asphalt pavements, composite pavements (rigid base) and combined base asphalt pavements. Flexible base asphalt pavements refer to pavements with asphalt-stabilized graded crushed stone or graded crushed stone as the base layer material, and among them, the flexible base asphalt pavement with asphalt-stabilized graded crushed stone as the base layer is also called a full-depth asphalt pavement; semi-rigid base asphalt pavements usually refer to pavements with cement-stabilized graded crushed stone as the base layer material; composite pavements refer to pavements with cement concrete as the base layer material, and their base layer strength is significantly improved compared with flexible base and semi-rigid base; as the name implies, combined base asphalt pavements refer to pavement structures with the base layer composed of different types of materials, usually composed of a semi-rigid base and a flexible base, such as a structure with graded crushed stone as the upper base layer and a semi-rigid base as the lower base layer and sub-base layer (also called an inverted structure).

[0004] In China's highway engineering, the most commonly used is semi-rigid base asphalt pavement, accounting for more than 90%. Cracks are typical diseases of such asphalt pavements, especially transverse cracks are the most common diseases on China's expressways. In addition, net cracks caused by water entering the pavement interior are also relatively common on national and provincial trunk highways and low-grade roads. The reasons for pavement cracking are, firstly, the shrinkage cracking (dry shrinkage and temperature shrinkage) of semi-rigid base materials themselves, which causes reflection cracks to appear in asphalt pavements; secondly, semi-rigid base materials are highly sensitive to loads, and their strength and modulus will decay due to fatigue effects under the coupling of heavy vehicle loads, dry-wet and freeze-thaw cycles, and gradually change from a whole to large blocks, from large blocks to small blocks and broken blocks, resulting in a decline in pavement bearing capacity and cracking. Summary of the Invention

[0005] In view of the above analysis, the embodiments of the present invention aim to provide a construction method for a crack-resistant heavy-duty traffic highway asphalt pavement to solve the problems of cracks in existing highway asphalt pavements and deficiencies in the pavement structure, and it is particularly applicable to heavy-duty traffic grade highways.

[0006] The object of the present invention is mainly achieved through the following technical solutions:

[0007] A design and construction method for a crack-resistant heavy-duty traffic highway asphalt pavement includes the following steps:

[0008] Step 1. Determine the pavement structure based on the bearing capacity of the pavement, and determine the construction sequence. The pavement structure from top to bottom includes a surface wearing course, a high-modulus asphalt concrete layer, a base course, and a sub-base course. Among them, the compressive dynamic modulus of the high-modulus asphalt concrete layer at 15°C and 10 Hz is 18,000 - 20,000 MPa;

[0009] Step 2. Pave the sub-base course. The roadbed within 80 - 120 cm below the sub-base course is improved with cement or lime. After construction and curing are completed, the sub-base course is paved in a single layer at one time, with a thickness of 16 - 20 cm;

[0010] Step 3. After the construction and curing of the sub-base course are completed, pave the base course in a single layer with a thickness of 16 - 20 cm, and the total thickness is 16 - 40 cm;

[0011] Step 4. After the construction and curing of the base course are completed, carry out the construction of a fiber crack-resistant modified asphalt waterproof bonding layer;

[0012] Step 5. After the construction of the fiber crack-resistant modified asphalt waterproof bonding layer is completed, pave the high-modulus asphalt concrete layer, and the compaction thickness is 5 - 15 cm;

[0013] Step 6. Pave the intermediate bonding layer and the surface wearing course, or directly pave the surface wearing course.

[0014] Furthermore, in Step 1, the base course includes an upper base course and a lower base course. The compressive dynamic modulus of the surface wearing course is 7,500 - 12,000 MPa, the compressive dynamic modulus of the upper base course is 18,000 - 28,000 MPa, the compressive dynamic modulus of the lower base course is 18,000 - 28,000 MPa, and the compressive dynamic modulus of the sub-base course is 14,000 - 20,000 MPa; In Step 3, the lower base course and the upper base course are paved in a single layer in sequence, and the thicknesses of the lower base course and the upper base course are the same.

[0015] Furthermore, in Step 1, the compressive dynamic modulus M satisfies the following relational expression:

[0016] M = -3000×L 2 +21000×L - 12000

[0017] where M is the compressive dynamic modulus at 15°C and 10 Hz in MPa;

[0018] L is the layer number of the pavement structure from top to bottom, taking values of 2, 3, 4, and 5, representing the high-modulus asphalt concrete layer, upper base course, lower base course, and subbase course respectively.

[0019] Furthermore, in step 4, after the base course construction and curing are completed, an emulsified asphalt prime coat is sprayed on the top surface of the base course. PC-2 type emulsified asphalt is used, and the spraying amount is 1.1 ± 0.1 L / m 2 , and the penetration depth of the emulsified asphalt is not less than 5 mm. After the prime coat emulsified asphalt breaks and emulsifies for 1 - 2 days, the fiber-reinforced crack-resistant modified asphalt waterproof bonding layer is constructed.

[0020] Furthermore, in the said step 4, the fiber-reinforced crack-resistant modified asphalt waterproof bonding layer is composed of modified asphalt, glass fiber, and crushed stone, and is formed by one-time spreading with a fiber synchronous chip seal truck. Among them, the spraying amount of the modified asphalt is 1.8 - 2.0 kg / m 2 ; the length of the glass fiber is 40 - 60 mm, and the spreading amount is 80 - 120 g / m 2 ; the crushed stone uses S10, that is, single-sized coarse aggregate with a specification of 10 - 15, and the spreading amount is 5 - 8 m 3 / 1000 m 2 .

[0021] Furthermore, in the said step 5, the high-modulus asphalt concrete is composed of asphalt binder and mineral aggregate. Road petroleum asphalt with a penetration of 20 / 0.1 mm is used, and the asphalt-aggregate ratio is 5.0%. By mass percentage, the particle size gradation range of the mineral aggregate is: the mineral aggregate with a particle size less than 0.075 mm accounts for 5% - 8% of the total mineral aggregate, the mineral aggregate with a particle size less than 0.6 mm accounts for 11% - 20% of the total mineral aggregate, the mineral aggregate with a particle size less than 1.18 mm accounts for 18% - 30% of the total mineral aggregate, the mineral aggregate with a particle size less than 2.36 mm accounts for 28% - 40% of the total mineral aggregate, the mineral aggregate with a particle size less than 4.75 mm accounts for 42% - 58% of the total mineral aggregate, the mineral aggregate with a particle size less than 9.5 mm accounts for 63% - 76% of the total mineral aggregate, the mineral aggregate with a particle size less than 13.2 mm accounts for 75% - 87% of the total mineral aggregate, the mineral aggregate with a particle size less than 16 mm accounts for 86% - 95% of the total mineral aggregate, and the mineral aggregate with a particle size less than 19 mm accounts for 100% of the total mineral aggregate.

[0022] Further, in the step 5, the average compaction thickness and the minimum compaction thickness of the high modulus asphalt concrete layer match the nominal maximum size of the aggregates, specifically: when the nominal maximum size of the aggregates is 9.5 mm, the average compaction thickness is 6 cm to 8 cm, and the minimum compaction thickness is 5 cm; when the nominal maximum size of the aggregates is 13.2 mm, the average compaction thickness is 7 cm to 13 cm, and the minimum compaction thickness is 6 cm; when the nominal maximum size of the aggregates is 16 mm, the average compaction thickness is 8 cm to 14 cm, and the minimum compaction thickness is 7 cm; when the nominal maximum size of the aggregates is 19 mm, the average compaction thickness is 9 cm to 15 cm, and the minimum compaction thickness is 8 cm.

[0023] Further, in the step 6, the compression dynamic modulus M satisfies the following relationship:

[0024] The compression dynamic modulus M satisfies the following relationship:

[0025] M = -2400×L 2 +21500×L - 24000

[0026] In the formula, M is the compression dynamic modulus at 15°C and 10 Hz / MPa;

[0027] L is the layer number from top to bottom of the pavement structure, and the values 2, 3, 4, 5, 6 represent the intermediate binder course, high modulus asphalt concrete layer, upper base course, lower base course and subbase course respectively.

[0028] Further, in the step 6, after the construction of the high modulus asphalt concrete layer is completed, a tack coat is sprayed. The tack coat uses PCR modified emulsified asphalt, and the spraying amount is 0.4 ± 0.1 L / m 2 , after the modified emulsified asphalt tack coat breaks and the water evaporates, the asphalt concrete intermediate binder course and the surface wearing course are paved in sequence, or directly the asphalt surface wearing course is paved.

[0029] Further, when the asphalt concrete intermediate binder course and the asphalt surface wearing course are paved in sequence, after the construction of the intermediate binder course is completed, a modified asphalt waterproof bonding layer is sprayed. The modified asphalt waterproof bonding layer is composed of SBS modified asphalt and crushed stones. The spraying amount of SBS modified asphalt is 1.6 - 2.0 kg / m 2 , the crushed stones use S10, that is, single-sized coarse aggregates with a size of 10 - 15, and the spreading amount is 5 - 8 m 3 / 1000 m 2 , the coverage rate is 50% - 70%, and then the surface wearing course is paved.

[0030] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0031] 1. Improve the stress state of the pavement structure and enhance the crack resistance of the pavement.

[0032] For the pavement structure fabricated by the method of the present invention, the compression dynamic moduli of the materials of all structural layers are gradually and coordinately transitioned, which helps the structural layers of the pavement structure to jointly bear forces. The fatigue failure times of the high-modulus asphalt mixture used in the high-modulus asphalt concrete layer are increased by about 1 time compared with the commonly used asphalt mixture of No. 70 or No. 90. At the same time, a fiber crack-resistant modified asphalt waterproof bonding layer is provided between the base course and the high-modulus asphalt concrete layer. On the one hand, it plays a role in absorbing the reflected stress of the base course cracking, and on the other hand, it also enhances the waterproof effect of the pavement structure. Therefore, the anti-cracking performance of the structure proposed by the present invention is significantly improved.

[0033] 2. Improve the bearing capacity of the pavement structure and be applicable to highways with heavy traffic grades.

[0034] For the pavement structure fabricated by the construction method of the present invention, the compression dynamic modulus range of the high-modulus asphalt concrete layer at 15°C and 10 Hz is 18,000 - 20,000 MPa, which is nearly doubled compared with the lower surface layer of the traditional structure. Therefore, it helps to improve the bearing capacity of the pavement structure and is more applicable to highways with heavy traffic grades.

[0035] 3. Reduce the pavement thickness, be low-carbon and environmentally friendly, and reduce the initial construction cost.

[0036] Due to the improvement of the pavement bearing capacity, under the condition of the same traffic volume, the thickness of the asphalt layer in this pavement structure can be reduced by 2 - 4 cm compared with the traditional structure scheme, reducing the consumption of stone materials and asphalt. While achieving energy conservation and environmental protection, it can also reduce the project cost. Under the condition of the same traffic volume, the number and length of cracks of the high-modulus asphalt pavement proposed in this application can be reduced by more than 80% compared with the currently commonly used asphalt pavement.

[0037] 4. Prolong the service life of the pavement and reduce the life cycle cost.

[0038] For the high-modulus asphalt mixture in the high-modulus asphalt concrete layer of the present invention, the fatigue failure times are increased by about 1 time compared with the commonly used asphalt mixture of No. 70 or No. 90, that is, the time of fatigue cracking of the high-modulus asphalt concrete layer will be significantly delayed. Therefore, the improvement of the bearing capacity and anti-cracking performance of this pavement structure helps to delay the occurrence of diseases such as pavement cracking and water damage, ensure the continuous durability of the pavement service performance, thus prolong the service life, reduce the daily maintenance workload, and reduce the life cycle cost.

[0039] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination schemes. Other features and advantages of the present invention will be described in the subsequent specification, and some advantages can be made obvious from the specification or understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained through the content specifically pointed out in the specification and the drawings. Description of the Drawings

[0040] The accompanying drawings are only for the purpose of showing specific embodiments and are not considered to be a limitation of the present invention. Throughout the drawings, the same reference numerals represent the same components.

[0041] Figure 1 It is the road surface structure diagram of Embodiment 1 of the present invention;

[0042] Figure 2 It is the road surface structure diagram of Embodiment 2 of the present invention;

[0043] Figure 3 It is the road surface structure diagram of Embodiment 3 of the present invention;

[0044] Figure 4 It is the road surface structure diagram of Embodiment 4 of the present invention.

[0045] Reference numerals of the accompanying drawings:

[0046] 11: Stone Mastic Asphalt SMA-13; 12: SBS Modified Asphalt Waterproof Bonding Layer; 13: Modified Asphalt Concrete AC-20; 14: Modified Emulsified Asphalt Tack Coat; 15: High Modulus Asphalt Concrete HMAC-20; 16: Prime Coat + Fiber Anti-Cracking Modified Asphalt Waterproof Bonding Layer; 17: Cement Stabilized Graded Crushed Stone Upper Base CBG-25; 18: Dry Cement; 19: Cement Stabilized Graded Crushed Stone Lower Base CBG-25; 10: Cement Stabilized Graded Crushed Stone Subbase CBG-25;

[0047] 21: Stone Mastic Asphalt SMA-13; 22: SBS Modified Asphalt Waterproof Bonding Layer; 23: High Modulus Asphalt Concrete HMAC-16; 24: Modified Emulsified Asphalt Tack Coat; 25: High Modulus Asphalt Concrete HMAC-20; 26: Prime Coat + Fiber Anti-Cracking Modified Asphalt Waterproof Bonding Layer; 27: Cement Stabilized Graded Crushed Stone Upper Base CBG-25; 28: Dry Cement; 29: Cement Stabilized Graded Crushed Stone Lower Base CBG-25; 20: Cement Stabilized Graded Crushed Stone Subbase CBG-25;

[0048] 31: Stone Mastic Asphalt SMA-13; 32: SBS Modified Emulsified Asphalt Tack Coat; 33: High Modulus Asphalt Concrete HMAC-20; 34: Prime Coat + Fiber Anti-Cracking Modified Asphalt Waterproof Bonding Layer; 35: Cement Stabilized Graded Crushed Stone Upper Base CBG-25; 36: Dry Cement; 37: Cement Stabilized Graded Crushed Stone Lower Base CBG-25; 38: Cement Stabilized Graded Crushed Stone Subbase CBG-25;

[0049] 41: Stone Matrix Asphalt SAC-13; 42: SBS Modified Emulsified Asphalt Tack Coat; 43: High Modulus Asphalt Concrete HMAC-16; 44: Prime Coat + Fiber-Reinforced Crack-Resistant Modified Asphalt Waterproof Bonding Layer; 45: Cement-Stabilized Graded Crushed Stone Base Course CBG-25; 46: Dry Cement; 47: Cement-Stabilized Graded Crushed Stone Subbase Course CBG-25. Detailed Implementation Manner

[0050] The preferred embodiments of the present invention will be specifically described below in conjunction with the accompanying drawings. The accompanying drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principles of the present invention, rather than to limit the scope of the present invention.

[0051] The present invention provides a design and construction method for a crack-resistant heavy-duty traffic highway asphalt pavement, which is characterized by including the following steps:

[0052] Step 1. Determine the pavement structure based on the bearing capacity of the pavement, determine the construction sequence. The pavement structure from top to bottom includes a surface wearing course, a high modulus asphalt concrete layer, a base course, and a subbase course. The compression dynamic modulus of the high modulus asphalt concrete layer at 15°C and 10 Hz is 18,000 - 20,000 MPa.

[0053] Step 2. Pave the subbase course. The roadbed within 80 - 120 cm below the subbase course is improved with cement or lime. After construction and curing are completed, the subbase course is paved in a single layer at one time, with a thickness of 16 - 20 cm.

[0054] Step 3. After the construction and curing of the subbase course are completed, the base course is paved in a single layer with a thickness of 16 - 20 cm, and the total thickness is 16 - 40 cm.

[0055] Step 4. After the construction and curing of the base course are completed, construct the fiber-reinforced crack-resistant modified asphalt waterproof bonding layer.

[0056] Step 5. After the construction of the fiber-reinforced crack-resistant modified asphalt waterproof bonding layer is completed, pave the high modulus asphalt concrete layer, with a compacted thickness of 5 - 15 cm.

[0057] Step 6. Pave the intermediate bonding layer and the surface wearing course, or directly pave the surface wearing course.

[0058] Compared with the existing structural design of asphalt pavements for heavy-duty traffic highways, the compression dynamic modulus of the materials of each structural layer of the pavement structure of the present invention is gradually coordinated and transitioned, which helps the structural layers of the pavement structure to jointly bear the load. The fatigue failure times of the high-modulus asphalt mixture used in the high-modulus asphalt concrete layer are increased by about 1 time compared with the commonly used No. 70 or No. 90 asphalt mixtures. At the same time, a fiber crack-resistant modified asphalt waterproof bonding layer is provided between the base course and the high-modulus asphalt concrete layer. On the one hand, it plays a role in absorbing the reflected stress of the base course cracking, and on the other hand, it also strengthens the waterproof effect of the pavement structure. The anti-cracking performance of the structure proposed by the present invention is significantly improved.

[0059] In order to achieve the gradual coordination and transition of the compression dynamic modulus of the materials of each structural layer and facilitate the joint force-bearing of each structural layer of the pavement structure, the present invention designs the base course as an upper base course and a lower base course, and designs the multi-layer compression dynamic modulus based on the two-layer base course structure. Under the conditions of 15 °C and 10 Hz, the compression dynamic modulus of the surface wearing course is 7500-12000 MPa; under the condition of 10 Hz, the compression dynamic modulus of the upper base course is 18000-28000 MPa, the compression dynamic modulus of the lower base course is 18000-28000 MPa, and the compression dynamic modulus of the sub-base course is 14000-20000 MPa.

[0060] The compression dynamic modulus range of the high-modulus asphalt concrete layer under the conditions of 15 °C and 10 Hz is 18000-20000 MPa, while the compression dynamic modulus of the traditional No. 70 asphalt mixture is generally about 12000 MPa, and the compression dynamic modulus of the No. 90 asphalt mixture is about 11000 MPa. Therefore, it is increased by nearly 1 time compared with the traditional structure, which helps to improve the bearing capacity of the pavement structure and is more suitable for heavy-duty traffic grade highways. The compression dynamic modulus of the materials of each structural layer of this pavement structure shows a gradient change and coordinated transition, which is beneficial to reducing the interlayer shear effect under the action of vehicle loads on each structural layer and improving the working performance of each structural layer to jointly bear the load, that is, improving the overall working performance of the pavement structure, thereby being beneficial to reducing the bottom stress and strain of each structural layer, especially the asphalt mixture layer, and improving the anti-cracking performance. The four-point bending fatigue test results show that under the conditions of 10 °C, 10 Hz, and 240 με, the fatigue failure times of the high-modulus asphalt mixture in the high-modulus asphalt concrete layer are not less than 1 million times, while the fatigue failure times of the commonly used No. 70 or No. 90 asphalt mixtures are about 450,000 times. That is, the time of fatigue cracking of the high-modulus asphalt concrete layer of the pavement structure proposed by the present invention will be significantly delayed, and the service life will be significantly extended.

[0061] Preferably, in step 1, the compression dynamic modulus M satisfies the following relational expression:

[0062] M = -3000×L 2 +21000×L - 12000

[0063] wherein, M is the compressive dynamic modulus at 15°C and 10 Hz, in MPa;

[0064] L is the layer number of the pavement structure from top to bottom, and the values are 2, 3, 4, and 5, representing the high-modulus asphalt concrete layer, the upper base course, the lower base course, and the subbase course respectively.

[0065] Specifically, in step 3, after the construction and curing of the subbase course are completed, dry cement is spread on the surface of the subgrade, and the cement spreading amount is 1.5 ± 0.1 kg / m 2 , and after 1 - 2 h, the base course is paved with cement-stabilized graded crushed stone. The single-layer paving thickness is 16 - 20 cm, and the total thickness is 16 - 40 cm. When necessary, it can be paved in layers according to the specific design thickness.

[0066] Specifically, in step 4, after the construction and curing of the base course are completed, an emulsified asphalt prime coat is sprayed on the top surface of the base course. PC-2 type emulsified asphalt is used, and the spraying amount is 1.1 ± 0.1 L / m 2 , and the penetration depth of the emulsified asphalt is not less than 5 mm. After the prime coat emulsified asphalt breaks and sets for 1 - 2 d, the fiber crack-resistant modified asphalt waterproof bonding layer is constructed.

[0067] It should be noted that the emulsified asphalt prime coat is set on the top surface of the base course to improve the bonding effect between the asphalt waterproof bonding layer and the cement-stabilized crushed stone base course.

[0068] Specifically, in the above step 4, the fiber crack-resistant modified asphalt waterproof bonding layer is composed of modified asphalt, glass fiber, and crushed stone, and is formed by one-time spreading with a fiber synchronous chip seal truck. The spreading amount of the modified asphalt is 1.8 - 2.0 kg / m 2 ; the length of the glass fiber is 40 - 60 mm, and the spreading amount is 80 - 120 g / m 2 ; the crushed stone uses S10, that is, single-sized coarse aggregate with a specification of 10 - 15, and the spreading amount is 5 - 8 m 3 / 1000 m 2 , and the coverage rate is preferably 55% - 60%. It should be noted that in the above step 4, the modified asphalt in the fiber crack-resistant modified asphalt waterproof bonding layer is polymer modified asphalt, including any one or two of SBS modified asphalt and rubber modified asphalt.

[0069] It should be noted that in order to improve the crack resistance and waterproof performance of the pavement structure, a fiber-reinforced modified asphalt waterproof bonding layer is provided between the high-modulus asphalt concrete layer and the base layer. Compared with the existing waterproof bonding layer, the fiber-reinforced modified asphalt waterproof bonding layer mainly adds fibers. The fibers are distributed in the asphalt and bonded to the asphalt, and the asphalt is simultaneously bonded to the upper and lower structural layers. Thus, the fibers can play a reinforcing role, absorb the stress at the crack tip of the lower layer, and improve the crack resistance. In terms of construction, a fiber and aggregate synchronous sealing truck is required for the fiber-reinforced modified asphalt waterproof bonding layer, while a common waterproof bonding layer only needs an aggregate synchronous sealing truck.

[0070] When the fiber-reinforced modified asphalt waterproof bonding layer adopts the above parameters, on the one hand, it can ensure the waterproof, bonding and crack resistance effects of the functional layer, and on the other hand, it ensures convenient construction and strong operability. If the aggregate specifications and spreading amount are carried out according to the above requirements, it effectively ensures that the asphalt spread during the construction process is not adhered and taken away by the construction vehicles.

[0071] Specifically, the high-modulus asphalt concrete layer is preferably HMAC20, and its composition is as follows: road petroleum asphalt with a penetration of 20 / 0.1 mm is used, the asphalt-aggregate ratio is 5.0%, and the grading range of the mineral aggregate particle size D in mass percentage is shown in Table 1. Specifically: 5% ≤ D 0.075 ≤ 8%, 11% ≤ D 0.6 ≤ 20%, 18% ≤ D 1.18 ≤ 30%, 28% ≤ D 2.36 ≤ 40%, 42% ≤ D 4.75 ≤ 58%, 63% ≤ D 9.5 ≤ 76%, 75% ≤ D 13.2 ≤ 87%, 86% ≤ D 16 ≤ 95%, D 19 = 100%. For example, 42% ≤ D 4.75 ≤ 58% means that the range of the mineral aggregate with a particle size less than 4.75 mm in the total amount is 42% - 58%.

[0072] It should be noted that since the penetration of the asphalt binder has a significant impact on the modulus of the mixture, the smaller the penetration, the higher the modulus of the mixture. The void ratio has a great impact on both the modulus and the anti-fatigue performance of the mixture. The larger the void ratio, the worse the modulus and the anti-fatigue performance of the mixture.

[0073] Considering the influence of the penetration and void ratio of the asphalt binder, in order to meet the technical requirements, the void ratio requirement of the above high-modulus asphalt concrete is 2% - 4%. A suspended dense-type mineral aggregate gradation is adopted. The asphalt binder preferably uses road petroleum asphalt with a penetration not greater than 30 / 0.1 mm. When using road petroleum asphalt with a penetration greater than 30 / 0.1 mm, additives that help improve the modulus of the mixture need to be added to the asphalt mixture.

[0074] The preferred aggregate gradation ranges of high modulus asphalt concrete corresponding to different nominal maximum particle sizes D are shown in Table 1:

[0075] Table 1 Aggregate gradation ranges of high modulus asphalt concrete with different nominal maximum particle sizes (wt%)

[0076]

[0077] Among them, for HMAC10: 6.5% ≤ D 0.075 ≤ 7.5%, 13% ≤ D 0.6 ≤ 30%, 20% ≤ D 1.18 ≤ 35%, 31% ≤ D 2.36 ≤ 43%, 45% ≤ D 4.75 ≤ 70%, D 9.5 = 100%;

[0078] For HMAC13: 5% ≤ D 0.075 ≤ 8%, 12% ≤ D 0.6 ≤ 22%, 18% ≤ D 1.18 ≤ 28%, 28% ≤ D 2.36 ≤ 42%, 43% ≤ D 4.75 ≤ 60%, 60% ≤ D 9.5 ≤ 75%, D 13.2 = 100%;

[0079] For HMAC16: 5% ≤ D 0.075 ≤ 8%, 13% ≤ D 0.6 ≤ 22%, 20% ≤ D 1.18 ≤ 32%, 30% ≤ D 2.36 ≤ 44%, 44% ≤ D 4.75 ≤ 60%, 63% ≤ D 9.5 ≤ 78%, 78% ≤ D 13.2 ≤ 90%, D 16 = 100%;

[0080] For HMAC20: 5% ≤ D 0.075 ≤ 8%, 11% ≤ D 0.6 ≤ 20%, 18% ≤ D 1.18 ≤ 30%, 28% ≤ D 2.36 ≤ 40%, 42% ≤ D 4.75 ≤ 58%, 63% ≤ D 9.5 ≤ 76%, 75% ≤ D 13.2 ≤ 87%, 86% ≤ D 16 ≤ 95%, D 19 = 100%.

[0081] For example, 42% ≤ D4.75 ≤58% means that the range of the aggregate with a particle size less than 4.75 mm in the total amount is 42% - 58%.

[0082] The high modulus asphalt concrete layer prepared by the above method, such as HMAC-10, HMAC-13, HMAC-16, HMAC-20, has a compressive dynamic modulus of not less than 18000 MPa at 15 °C and 10 Hz, which is higher than the control standard of 14000 MPa for ordinary high modulus asphalt mixtures. In addition, the number of four-point bending fatigue failures under the conditions of 10 °C, 10 Hz, and 240 με can reach more than 1 million times.

[0083] Specifically, the average compaction thickness H of the high modulus asphalt concrete layer average and the minimum compaction thickness H min match the nominal maximum particle size D of the aggregate as shown in Table 2, specifically: 6 ≤ H average (D 9.5 ) ≤ 8, H min (D 9.5 ) = 5; 7 ≤ H average (D 13.2 ) ≤ 13, H min (D 13.2 ) = 6; 8 ≤ H average (D 16 ) ≤ 14, H min (D 16 ) = 7; 9 ≤ H average (D 19 ) ≤ 15, H min (D 16 ) = 8. For example, 8 ≤ H average (D 16 ) ≤ 14, H min (D 16 ) = 7 means that when the nominal maximum particle size of the aggregate used is 16 mm, the average compaction thickness is 8 - 14 cm, and the minimum compaction thickness is 7 cm.

[0084] Table 2 Matching relationship between the compaction thickness of the high modulus asphalt concrete layer and the nominal maximum particle size of the aggregate

[0085] Nominal maximum particle size / mm 9.5 13.2 16.0 19.0 Minimum compaction thickness / cm 5 6 7 8 Average compaction thickness / cm 6-8 7-13 8-14 9-15

[0086] Specifically, in step 6, when paving the intermediate bonding layer, the compressive dynamic modulus M satisfies the following relationship:

[0087] M = -2400 × L 2 +21500 × L - 24000

[0088] In the formula, M is the compressive dynamic modulus at 15 °C and 10 Hz, MPa;

[0089] Let \(L\) be the layer number of the pavement structure from top to bottom, and the values are 2, 3, 4, 5, 6, representing the intermediate binder course, high modulus asphalt concrete layer, upper base course, lower base course and subbase course respectively.

[0090] Specifically, in step 6, after the construction of the high modulus asphalt concrete layer, a tack coat is sprayed. The tack coat preferably uses PCR modified emulsified asphalt, and the spraying amount is \(0.4\pm0.1\ L / m^2\). 2 After the modified emulsified asphalt tack coat breaks and the water evaporates, the intermediate binder course and the surface wearing course are successively paved immediately, or the surface wear-resistant layer is directly paved.

[0091] It should be noted that the material of the intermediate binder course is asphalt concrete, or high modulus asphalt concrete can also be used. The surface wear-resistant layer is any asphalt surface course material in the field of existing traffic roads, preferably asphalt pavement materials with large texture depth such as SMA - 13, SMA - 10, SAC - 13 and SAC - 10.

[0092] Specifically, in the above step 6, when the intermediate binder course and the surface wearing course are successively paved, a modified asphalt waterproof bonding layer is sprayed after the construction of the binder course. The modified asphalt waterproof bonding layer is composed of SBS modified asphalt and crushed stone. The spraying amount of SBS modified asphalt is \(1.6 - 2.0\ kg / m^2\). 2 The crushed stone uses S10, that is, single - sized coarse aggregate with a specification of 10 - 15, and the spreading amount is \(5 - 8\ m^3 / 1000\ m^2\). 3 / 1000m 2 with a coverage rate of 50% - 70%, and then the surface wearing course is paved immediately.

[0093] For the pavement structure prepared by the above construction method, the compression dynamic modulus of the high modulus asphalt concrete layer under the conditions of 15°C and 10 Hz ranges from 18000 to 20000 MPa. Generally, the compression dynamic modulus of the traditional material, 70 - grade asphalt mixture, is about 12000 MPa, and that of the 90 - grade asphalt mixture is about 11000 MPa. Therefore, it is nearly doubled compared with the lower layer of the traditional structure, which helps to improve the bearing capacity of the pavement structure and is more suitable for highways with heavy traffic grades.

[0094] The compression dynamic modulus of the surface wearing course of the pavement structure of the present invention is 7500 - 12000 MPa, the compression dynamic modulus of the high modulus asphalt concrete layer is 18000 MPa - 20000 MPa, the compression dynamic modulus of the base course is 18000 - 28000 MPa, and the compression dynamic modulus of the subbase course is 14000 - 20000 MPa. The compression dynamic modulus of the high modulus asphalt concrete layer is 1 time higher than the average value of the compression dynamic modulus of the surface wearing course, the base course is 0.21 times higher than the average value of the compression dynamic modulus of the high modulus asphalt concrete layer, and the subbase course is 0.25 times lower than the average value of the compression dynamic modulus of the base course. The compression dynamic moduli of the materials of each structural layer of this pavement structure show a gradient change and a coordinated transition, which is beneficial to reducing the interlayer shear effect of each structural layer under the action of vehicle loads, improving the working performance of the coordinated stress of each structural layer, that is, improving the overall working performance of the pavement structure, thereby being beneficial to reducing the bottom stress and strain of each structural layer, especially the asphalt mixture layer, and improving the crack resistance performance.

[0095] The results of the four-point bending fatigue test show that under the conditions of 10 °C, 10 Hz, and 240 με, the fatigue failure times of the high modulus asphalt mixture in the high modulus asphalt concrete layer are not less than 1 million times, while the fatigue failure times of the commonly used No. 70 or No. 90 asphalt mixture are about 450,000 times. That is, the time of fatigue cracking of the high modulus asphalt concrete layer of the pavement structure made by this construction method will be significantly delayed, and the service life will be significantly extended.

[0096] The present invention provides a fiber crack-resistant modified asphalt waterproof bonding layer between the base course and the high modulus asphalt concrete layer, which makes the coordinated transition of the compression dynamic moduli of the materials of each structural layer more optimized, improves the stress state of the pavement structure, plays a role in absorbing the reflected stress of the base course cracking on the one hand, and also strengthens the waterproof effect of the pavement structure on the other hand.

[0097] Since the pavement bearing capacity is greatly improved by the above preparation scheme, the thickness of the asphalt layer in the pavement structure can be reduced by 2 - 4 cm compared with the traditional structural scheme under the same traffic volume condition, reducing the construction cost.

[0098] The following are several specific implementation schemes of the present invention.

[0099] Example 1

[0100] The pavement structure from top to bottom is: 4 cm asphalt mastic stone asphalt SMA - 13, 6 cm modified asphalt concrete AC - 20, 8 cm high modulus asphalt concrete HMAC - 20, 20 cm cement stabilized graded crushed stone upper base course CBG - 25, 20 cm cement stabilized graded crushed stone lower base course CBG - 25, 20 cm cement stabilized graded crushed stone subbase course CBG - 25.

[0101] The construction method of the above pavement structure includes:

[0102] Step 1. To ensure the stability and durability of the road surface, the subgrade within 80 cm below the bottom base course of the road surface structure is improved with cement or lime to enhance the anti-plastic deformation ability of the subgrade. After the construction and curing of the soil improved with cement or lime are completed, the bottom base course is paved.

[0103] The bottom base course is made of cement-stabilized graded crushed stone with a thickness of 20 cm, and is paved in a single layer at one time. After the construction and curing of the bottom base course are completed, the base course is paved.

[0104] Step 2. The base course is made of cement-stabilized graded crushed stone and is paved in two layers, with each layer having a thickness of 20 cm.

[0105] Before the construction of the base course materials, the underlying layer is cleaned and the traffic is closed. 1 - 2 h before the construction of the base course, dry cement is spread on the surface of the underlying layer to enhance the interlayer bonding effect of the cement-stabilized materials. The amount of cement spread is 1.5 ± 0.1 kg / m 2 。

[0106] Step 3. After the construction and curing of the base course are completed, 1 day before the paving of the high-modulus asphalt concrete layer, an emulsified asphalt prime coat is sprayed on the top surface of the base course. PC-2 type emulsified asphalt is used, and the spraying amount is 1.1 ± 0.1 L / m2, and the penetration depth of the emulsified asphalt is 5 mm. After the prime coat emulsified asphalt breaks and demulsifies, the fiber crack-resistant modified asphalt waterproof bonding layer is constructed. The modified asphalt in the fiber crack-resistant modified asphalt waterproof bonding layer uses SBS modified asphalt, and the spraying amount is 1.8 kg / m 2 ; the length of the glass fiber is 40 mm, and the spreading amount is 80 g / m 2 ; the crushed stone uses S10, that is, single-sized coarse aggregate with a specification of 10 - 15, and the spreading amount is 5 m 3 / 1000 m 2 , and the coverage rate is 55%. It is spread and formed at one time by a fiber synchronous chip seal truck.

[0107] Step 4. After the construction of the fiber crack-resistant modified asphalt waterproof bonding layer is completed, the high-modulus asphalt concrete layer is immediately paved. The compacted thickness of the high-modulus asphalt concrete layer HMAC-20 is 8 cm.

[0108] Step 5. After the construction of the high-modulus asphalt concrete layer is completed, a tack coat is sprayed. PCR modified emulsified asphalt is used for the tack coat, and the spraying amount is 0.4 ± 0.1 L / m 2 。After the modified emulsified asphalt tack coat breaks and demulsifies and the water evaporates, the connecting layer, that is, modified asphalt concrete AC-20, is immediately paved, and the compacted thickness is 6 cm.

[0109] After the construction of the connecting layer is completed, the modified asphalt waterproof bonding layer is immediately constructed. The modified asphalt waterproof bonding layer is composed of SBS modified asphalt and crushed stone. The spraying amount of SBS modified asphalt is 1.8 kg / m 2, the crushed stones are single-sized coarse aggregates of S10, i.e., 10 - 15 specifications, and the spreading amount is 6 m 3 / 1000 m 2 , and the coverage rate is 60%.

[0110] Finally, the surface wearing course is paved, using asphalt mastic asphalt SMA - 13 with a thickness of 4 cm.

[0111] After testing, under the conditions of 15°C and 10 Hz, the surface layer compression dynamic modulus of the pavement structure in this embodiment is 9000 MPa, the compression dynamic modulus of the high - modulus asphalt concrete layer is 19000 MPa, the compression dynamic modulus of the base course is 25000 MPa, and the compression dynamic modulus of the sub - base course is 16000 MPa. The results of the four - point bending fatigue test show that under the conditions of 10°C, 10 Hz, and 240 με, the fatigue failure times of the high - modulus asphalt mixture in the high - modulus asphalt concrete layer are 1.1 million times. The test results after opening to traffic show that compared with the previous pavement structure, the thickness is reduced by 4 cm, but the crack length of the pavement structure in this embodiment is 24 m / km, the number of cracks is 6.8 cracks / km, and the crack length and number of adjacent normal sections are 138 m / km and 37.6 cracks / km respectively. The crack length and number of the anti - cracking heavy - duty traffic pavement structure are reduced by 82.6% and 81.9% respectively compared with the original design structure section.

[0112] Example 2

[0113] The pavement structure from top to bottom is: 4 cm asphalt mastic asphalt SMA - 13, 8 cm high - modulus asphalt concrete HMAC - 16, 10 cm high - modulus asphalt concrete HMAC - 20, 18 cm cement - stabilized graded crushed stones upper base course CBG - 25, 18 cm cement - stabilized graded crushed stones lower base course CBG - 25, 18 cm cement - stabilized graded crushed stones sub - base course CBG - 25.

[0114] The construction method of the above pavement structure includes:

[0115] Step 1: To ensure the stability and durability of the pavement, the subgrade within 100 cm below the sub - base course of the pavement structure is improved with cement or lime to enhance the anti - plastic deformation ability of the subgrade. After the construction and curing of the cement or lime improved soil, the sub - base course is paved.

[0116] The sub - base course uses cement - stabilized graded crushed stones with a thickness of 18 cm, and is paved in a single layer at one time. After the construction and curing of the sub - base course, the base course is paved.

[0117] Step 2: The base course uses cement - stabilized graded crushed stones and is paved in two layers, with each layer having a thickness of 18 cm.

[0118] Before the construction of the base course material, clean the underlying layer and close the traffic. Spread dry cement on the surface of the underlying layer 1-2 hours before the base course construction to enhance the interlayer bonding effect of the cement stabilized material. The cement spreading amount is 1.5±0.1 kg / m 2 .

[0119] Step 3: After the construction and curing of the base course, spray emulsified asphalt prime coat on the top surface of the base course 2 days before the paving of the high modulus asphalt concrete layer. Use PC-2 type emulsified asphalt, and the spraying amount is 1.1±0.1 L / m2. The penetration depth of the emulsified asphalt is 8 mm. After the emulsified asphalt in the prime coat breaks and demulsifies, construct the fiber crack-resistant modified asphalt waterproof bonding layer.

[0120] The modified asphalt in the fiber crack-resistant modified asphalt waterproof bonding layer adopts SBS modified asphalt, and the spraying amount is 2.0 kg / m 2 ; the glass fiber length is 60 mm, and the spreading amount is 100 g / m 2 ; the crushed stone adopts S10, that is, single-sized coarse aggregate with a specification of 10-15, and the spreading amount is 8 m 3 / 1000 m 2 , and the coverage rate is 60%. Use a fiber synchronous chip seal truck to spread and form in one pass.

[0121] Step 4: After the construction of the fiber crack-resistant modified asphalt waterproof bonding layer is completed, immediately pave the high modulus asphalt concrete layer. The compaction thickness of the high modulus asphalt concrete layer HMAC-20 is 10 cm.

[0122] Step 5: After the construction of the high modulus asphalt concrete layer is completed, spray tack coat. The tack coat adopts PCR modified emulsified asphalt, and the spraying amount is 0.4±0.1 L / m 2 . After the modified emulsified asphalt tack coat breaks and demulsifies and the water evaporates, immediately pave the connecting layer, using high modulus asphalt concrete HMAC-16, and the compaction thickness is 8 cm.

[0123] After the construction of the connecting layer is completed, immediately construct the modified asphalt waterproof bonding layer. The modified asphalt waterproof bonding layer is composed of SBS modified asphalt and crushed stone. The spraying amount of SBS modified asphalt is 1.6 kg / m 2 , the crushed stone adopts S10, that is, single-sized coarse aggregate with a specification of 10-15, and the spreading amount is 5 m 3 / 1000 m 2 , and the coverage rate is 50%.

[0124] Finally, pave the surface wearing course, using asphalt mastic asphalt SMA-13, with a thickness of 4 cm.

[0125] After testing, the compression dynamic modulus of the surface layer of the pavement structure in this embodiment is 9100 MPa at 15°C and 10 Hz, the compression dynamic modulus of the high-modulus asphalt concrete layer is 19500 MPa, the compression dynamic modulus of the base course is 23000 MPa, and the compression dynamic modulus of the subbase course is 15900 MPa. The results of the four-point bending fatigue test show that the fatigue failure times of the high-modulus asphalt mixture in the high-modulus asphalt concrete layer are 1.08 million times at 10°C, 10 Hz, and 240 με. The test results after the road is opened to traffic show that the thickness of the pavement structure is reduced by 2 cm compared with the previous one. However, the crack length of the pavement structure in this embodiment is 18.2 m / km, and the number of cracks is 8.3 cracks / km. The crack length and the number of cracks in the adjacent normal section are 129 m / km and 40.2 cracks / km respectively. The crack length and the number of cracks of the crack-resistant heavy-duty traffic pavement structure are reduced by 85.9% and 79.3% respectively compared with the original design structure section.

[0126] Example 3

[0127] The pavement structure from top to bottom is: 4 cm asphalt mastic stone asphalt SMA-13, 8 cm high-modulus asphalt concrete HMAC-20, 18 cm cement-stabilized graded crushed stone upper base course CBG-25, 18 cm cement-stabilized graded crushed stone lower base course CBG-25, 18 cm cement-stabilized graded crushed stone subbase course CBG-25.

[0128] The construction method of the above pavement structure includes:

[0129] Step 1. To ensure the stability and durability of the pavement, the subgrade within 120 cm below the subbase course of the pavement structure is improved with cement or lime to improve the anti-plastic deformation ability of the subgrade. After the construction and curing of the cement or lime improved soil are completed, the subbase course is paved.

[0130] The subbase course uses cement-stabilized graded crushed stone with a thickness of 18 cm and is paved in a single layer at one time. After the construction and curing of the subbase course are completed, the base course is paved.

[0131] Step 2. The base course uses cement-stabilized graded crushed stone and is paved in two layers, with each layer having a thickness of 18 cm.

[0132] Before the construction of the base course materials, the underlying layer is cleaned and the traffic is closed. Dry cement is spread on the surface of the underlying layer 1-2 hours before the construction of the base course to enhance the interlayer bonding effect of the cement-stabilized materials. The amount of cement spread is 1.5 ± 0.1 kg / m 2 .

[0133] Step 3: After the construction and curing of the base course, 2 days before the paving of the high modulus asphalt concrete layer, an emulsified asphalt prime coat is sprayed on the top surface of the base course. PC-2 type emulsified asphalt is used, with a spraying amount of 1.1 ± 0.1 L / m², and the penetration depth of the emulsified asphalt is 7 mm. After the emulsified asphalt of the prime coat breaks and demulsifies, the construction of the fiber-reinforced crack-resistant modified asphalt waterproof bonding layer is carried out.

[0134] The modified asphalt in the fiber-reinforced crack-resistant modified asphalt waterproof bonding layer uses SBS modified asphalt, with a spraying amount of 1.9 kg / m 2 ; the glass fiber length is 50 mm, and the spreading amount is 120 g / m 2 ; the crushed stone uses S10, that is, single-sized coarse aggregate with a specification of 10 - 15, and the spreading amount is 6 m 3 / 1000 m 2 , and the coverage rate is 57%. It is formed by one-time spreading using a fiber synchronous chip seal truck.

[0135] Step 4: After the construction of the fiber-reinforced crack-resistant modified asphalt waterproof bonding layer is completed, the high modulus asphalt concrete layer is immediately paved. The compaction thickness of the high modulus asphalt concrete layer HMAC-20 is 8 cm.

[0136] Step 5: After the construction of the high modulus asphalt concrete layer is completed, a tack coat is sprayed. PCR modified emulsified asphalt is used for the tack coat, with a spraying amount of 0.4 ± 0.1 L / m 2 . After the modified emulsified asphalt tack coat breaks and demulsifies and the water evaporates, the surface wearing course is immediately paved. Asphalt mastic asphalt SMA-13 is used, with a thickness of 4 cm.

[0137] After testing, the surface layer compression dynamic modulus of the pavement structure in this embodiment is 10000 MPa at 15°C and 10 Hz, the compression dynamic modulus of the high modulus asphalt concrete layer is 18700 MPa, the compression dynamic modulus of the base course is 19000 MPa, and the compression dynamic modulus of the sub-base course is 18000 MPa. The four-point bending fatigue test results show that under the conditions of 10°C, 10 Hz, and 240 με, the fatigue failure times of the high modulus asphalt mixture in the high modulus asphalt concrete layer are 1.2 million times. The test results after the road is opened to traffic show that the thickness of the pavement structure is reduced by 4 cm compared with the previous one. However, for the pavement structure in this embodiment, the crack length is 34 m / km, and the number of cracks is 11.2 pieces / km. The crack length and the number of cracks in the adjacent normal section are 148.2 m / km and 45.8 pieces / km respectively. The crack length and the number of cracks of the crack-resistant heavy-duty traffic pavement structure are reduced by 77% and 75.5% respectively compared with the original designed structure section.

[0138] Example 4

[0139] The pavement structure from top to bottom is as follows: 5 cm of multi-crushed stone asphalt concrete SAC-13, 7 cm of high modulus asphalt concrete HMAC-16, 20 cm of cement stabilized graded crushed stone base CBG-25, and 20 cm of cement stabilized graded crushed stone subbase CBG-25.

[0140] The construction method of the above pavement structure includes:

[0141] Step 1: To ensure the stability and durability of the pavement, the subgrade within 80 cm below the subbase of the pavement structure is improved with cement or lime to enhance the anti-plastic deformation ability of the subgrade. After the construction and curing of the cement or lime improved soil, the subbase is paved.

[0142] The subbase uses cement stabilized graded crushed stone with a thickness of 20 cm and is paved in a single layer at one time. After the construction and curing of the subbase, the base is paved.

[0143] Step 2: The base uses cement stabilized graded crushed stone and is paved in a single layer at one time with a thickness of 20 cm.

[0144] Before the construction of the base material, the underlying layer is cleaned and the traffic is closed. 1 - 2 hours before the construction of the base, dry cement is spread on the surface of the underlying layer to enhance the interlayer bonding effect of the cement stabilized material. The amount of cement spread is 1.5 ± 0.1 kg / m 2 。

[0145] Step 3: After the construction and curing of the base, 1 day before the paving of the high modulus asphalt concrete layer, an emulsified asphalt prime coat is sprayed on the top surface of the base. PC-2 type emulsified asphalt is used, and the spraying amount is 1.1 ± 0.1 L / m2. The penetration depth of the emulsified asphalt is 5 mm. After the prime coat emulsified asphalt breaks, the fiber anti-cracking modified asphalt waterproof bonding layer is constructed. The modified asphalt in the fiber anti-cracking modified asphalt waterproof bonding layer uses SBS modified asphalt, and the spraying amount is 1.8 kg / m 2 ; the glass fiber length is 40 mm, and the spreading amount is 80 g / m 2 ; the crushed stone uses S10, that is, single-sized coarse aggregate with a specification of 10 - 15, and the spreading amount is 5 m 3 / 1000 m 2 , and the coverage rate is 55%. It is spread and formed at one time by a fiber synchronous chip seal truck.

[0146] Step 4: After the construction of the fiber anti-cracking modified asphalt waterproof bonding layer is completed, the high modulus asphalt concrete layer is immediately paved. The compacted thickness of the high modulus asphalt concrete layer HMAC-16 is 7 cm.

[0147] Step 5: After the construction of the high modulus asphalt concrete layer is completed, a tack coat is sprayed. PCR modified emulsified asphalt is used for the tack coat, and the spraying amount is 0.4 ± 0.1 L / m 2After the modified emulsified asphalt tack coat breaks and the water evaporates, the surface wearing course is paved immediately. The multi-aggregate asphalt concrete SMA-13 with a thickness of 5 cm is used.

[0148] After testing, the surface layer compression dynamic modulus of the pavement structure in this embodiment is 11,000 MPa at 15°C and 10 Hz, the high modulus asphalt concrete layer compression dynamic modulus is 20,000 MPa, the base course compression dynamic modulus is 27,000 MPa, and the sub-base course compression dynamic modulus is 19,000 MPa. The four-point bending fatigue test results show that the fatigue failure times of the high modulus asphalt mixture in the high modulus asphalt concrete layer are 1.14 million times at 10°C, 10 Hz, and 240 με. The test results after the road is opened to traffic show that the thickness of the pavement structure is reduced by 3 cm compared with the previous one. However, the crack length of the pavement structure in this embodiment is 28 m / km, and the number of cracks is 8 cracks / km. The crack length and the number of cracks in the adjacent normal section are 130.9 m / km and 40 cracks / km respectively. The crack length and the number of cracks of the anti-cracking heavy-duty traffic pavement structure are reduced by 78.6% and 80% respectively compared with the original design structure section.

[0149] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A design and construction method for a crack-resistant heavy-load traffic highway asphalt pavement, characterized in that It includes the following steps: Step 1. Determine the pavement structure based on the bearing capacity of the road surface, and determine the construction sequence. The pavement structure from top to bottom includes a surface wearing course, a high-modulus asphalt concrete layer, a base course, and a sub-base course. At 15°C and 10 Hz, the compressive dynamic modulus of the surface wearing course is 7500 - 12000 MPa, the compressive dynamic modulus of the high-modulus asphalt concrete layer is 18000 - 20000 MPa, the compressive dynamic modulus of the base course is 18000 - 28000 MPa, and the compressive dynamic modulus of the sub-base course is 14000 - 16000 MPa; Step 2. Pave the sub-base course. The roadbed within 80 - 120 cm below the sub-base course is improved with cement or lime. After construction and curing, the sub-base course uses cement-stabilized graded crushed stone, and the sub-base course is paved in a single layer at one time with a thickness of 16 - 20 cm; Step 3. After the construction and curing of the sub-base course are completed, the base course uses cement-stabilized graded crushed stone, and the base course is paved in a single layer with a thickness of 16 - 20 cm, and the total thickness is 16 - 40 cm; Step 4. After the base course construction and curing are completed, an emulsified asphalt prime coat is sprayed on the top surface of the base course. PC-2 type emulsified asphalt is used, and the spraying amount is 1.1 ± 0.1 L / m 2 , and the penetration depth of the emulsified asphalt is not less than 5 mm. After the prime coat emulsified asphalt breaks and sets for 1-2 days, the fiber crack-resistant modified asphalt waterproof bonding layer is constructed; the fiber crack-resistant modified asphalt waterproof bonding layer is composed of modified asphalt, glass fiber and crushed stone, and is formed by one-time spreading with a fiber synchronous chip seal truck. The spraying amount of the modified asphalt is 1.8-2.0 kg / m 2 ; the length of the glass fiber is 40-60 mm, and the spreading amount is 80-120 g / m 2 ; the crushed stone uses S10, that is, single-sized coarse aggregate with a specification of 10-15, and the spreading amount is 5-8 m 3 / 1000 m 2 , and the coverage rate is 55%-60%; Step 5. After the construction of the fiber crack-resistant modified asphalt waterproof bonding layer is completed, pave the high-modulus asphalt concrete layer, and the compaction thickness is 5 - 15 cm; Step 6. Pave the intermediate bonding layer and the surface wearing course, or directly pave the surface wearing course.

2. The design and construction method according to claim 1, characterized in that, In the said Step 1, the base course includes an upper base course and a lower base course. The compressive dynamic modulus of the upper base course is 18000 - 28000 MPa, and the compressive dynamic modulus of the lower base course is 18000 - 28000 MPa; in the said Step 3, the lower base course and the upper base course are paved in a single layer in sequence, and the thicknesses of the lower base course and the upper base course are the same.

3. The design and construction method according to claim 1 or 2, characterized in that, In the said Step 5, the high-modulus asphalt concrete is composed of asphalt binder and mineral aggregate. Road petroleum asphalt with a penetration of 20 / 0.1 mm is used, and the asphalt-aggregate ratio is 5.0%. By mass percentage, the grading range of the mineral aggregate particle size is as follows: the mineral aggregate with a particle size less than 0.075 mm accounts for 5% - 8% of the total mineral aggregate, the mineral aggregate with a particle size less than 0.6 mm accounts for 11% - 20% of the total mineral aggregate, the mineral aggregate with a particle size less than 1.18 mm accounts for 18% - 30% of the total mineral aggregate, the mineral aggregate with a particle size less than 2.36 mm accounts for 28% - 40% of the total mineral aggregate, the mineral aggregate with a particle size less than 4.75 mm accounts for 42% - 58% of the total mineral aggregate, the mineral aggregate with a particle size less than 9.5 mm accounts for 63% - 76% of the total mineral aggregate, the mineral aggregate with a particle size less than 13.2 mm accounts for 75% - 87% of the total mineral aggregate, the mineral aggregate with a particle size less than 16 mm accounts for 86% - 95% of the total mineral aggregate, and the mineral aggregate with a particle size less than 19 mm accounts for 100% of the total mineral aggregate.

4. The design and construction method according to claim 1 or 2, characterized in that, In the said Step 5, the average compaction thickness and the minimum compaction thickness of the high modulus asphalt concrete layer are matched with the nominal maximum size of the aggregate, specifically: when the nominal maximum size of the aggregate is 9.5 mm, the average compaction thickness is 6 cm to 8 cm, and the minimum compaction thickness is 5 cm; when the nominal maximum size of the aggregate is 13.2 mm, the average compaction thickness is 7 cm to 13 cm, and the minimum compaction thickness is 6 cm; when the nominal maximum size of the aggregate is 16 mm, the average compaction thickness is 8 cm to 14 cm, and the minimum compaction thickness is 7 cm; when the nominal maximum size of the aggregate is 19 mm, the average compaction thickness is 9 cm to 15 cm, and the minimum compaction thickness is 8 cm.

5. The design and construction method according to claim 1 or 2, characterized in that, In the said step 6, after the construction of the high modulus asphalt concrete layer, a tack coat is sprayed. The tack coat uses PCR modified emulsified asphalt, and the spraying amount is 0.4 ± 0.1 L / m 2 . After the modified emulsified asphalt tack coat breaks and the water evaporates, the asphalt concrete intermediate bonding layer and the surface wearing course are paved in sequence, or directly the asphalt surface wearing course is paved.

6. The design and construction method according to claim 5, characterized in that, When laying the asphalt concrete intermediate binder course and the asphalt surface wearing course in sequence, a modified asphalt waterproof bonding layer is sprayed after the construction of the intermediate binder course. The modified asphalt waterproof bonding layer is composed of SBS modified asphalt and crushed stones. The spraying amount of SBS modified asphalt is 1.6 - 2.0 kg / m 2 , and the crushed stones adopt S10, that is, single-sized coarse aggregates with a specification of 10 - 15. The spreading amount is 5 - 8 m 3 / 1000 m 2 , the coverage rate is 50% - 70%, and then the surface wearing course is laid.

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