Prefabricated rollable composite thin-layer asphalt pavement and preparation method thereof

Abstract

The invention discloses a prefabricated flexible composite thin-layer asphalt pavement and a preparation method thereof. The composite thin-layer asphalt pavement comprises a modified asphalt mixture layer A and a modified asphalt mixture layer B which are different in gradation, the first bonding layer, the base material layer and the second bonding layer are located between the modified asphalt mixture A layer and the modified asphalt mixture B layer, the thickness of the composite thin-layer asphalt pavement is 2-2.5 cm, and the curl radius is determined according to a small beam bending test. The prefabricated rollable composite thin-layer asphalt pavement disclosed by the invention is thin in thickness, can be rollable into a small-radius structure, can greatly reduce the weight per unit area, increases the characteristics of high flexible repairing quality of the prefabricated pavement, is relatively weak in influence on the elevation of the pavement, does not need grooving paving, can quickly repair the pavement and harden the ground, and realizes carpet-type paving; and the driving performance of the pavement exceeds that of a common thin-layer asphalt pavement.

Description

Technical Field

[0001] The invention belongs to the technical field of thin-layer asphalt pavement, and in particular relates to a prefabricated rollable composite thin-layer asphalt pavement and a preparation method thereof. Background Art

[0002] Thin-layer pavement is an asphalt pavement pre-maintenance process that adds a layer of asphalt mixture to the original pavement to repair the pavement's road function and inhibit the progression of pavement diseases. According to the 2024 China Pavement Engineering Academic Research Review of the China Journal of Highway and Transport, pavement structure layers with a thickness of 4 to 2.5 cm are called thin layers, and those less than 2.5 cm are called ultra-thin layers. In addition to repairing the original pavement function, some thin-layer pavements can give the repaired pavement noise reduction, anti-skid, anti-rutting and other functions through asphalt binder modification and aggregate grading adjustment. It has the advantages of low engineering cost, short construction period, and the ability to solve mild and moderate pavement diseases.

[0003] Curled pavement is a new thin-layer process that curls traditional thin-layer pavement into shape, prefabricates the finished pavement in the factory, grooves it on site, spreads tack oil, and rolls it into shape. Because it is prefabricated in the factory, it greatly overcomes the problem of large variability in asphalt mixture construction, ensures the quality of the pavement, and effectively extends the service life of the asphalt pavement. At the same time, due to the curling forming, the paving speed is faster, and the repair period is shorter than that of traditional thin-layer technology. The finished coiled material can be constructed in a variety of extreme environments, which is of great significance for the rapid restoration of road traffic in emergency rescue and disaster relief.

[0004] However, the structural characteristics of the prefabricated curly asphalt pavement process require the asphalt mixture to be bent. Bending will cause the surface layer of the structure to be compressed and the bottom layer to be tensile, which is prone to reflective cracks in the base layer, thus affecting the road performance of the entire thin layer. Ordinary asphalt and asphalt mixtures are difficult to meet the bending performance requirements. It is necessary to perform composite modification on the asphalt and redesign the structure so that the upper layer of asphalt mixture can meet the compression and the lower layer of asphalt mixture can meet the tension. The entire ultra-thin structural layer can be prefabricated by bending without affecting the road performance, so as to achieve the purpose of carpet paving.

[0005] There are few studies on prefabricated asphalt pavements in China. Prefabricated pavement repair technology is more focused on several technical systems such as anti-cracking paste, cold patch material, and modular pavement installation. The former lacks graded asphalt mixtures, and the latter has poor road performance with cold mix materials. Modular prefabricated pavements destroy the continuous layered system of asphalt pavements, with more horizontal and vertical lap joints and weak water damage resistance. Regarding hot-mix prefabricated continuous asphalt pavement technology, domestic research is mainly the carpet-type pavement research conducted by Cao Dongwei of the Highway Science Research Institute and Dong Yuanshuai of the Highway Pavement Maintenance Technology Research and Development Center of Jiaojian, and some test sections were paved on Ma Da Road in Tongzhou District, Beijing. The test road has good results and can quickly repair and renovate the pavement, but its pavement structure layer is mainly based on the 4cm thick upper layer, which is transported to the site for paving after prefabrication. Since the asphalt mixture is mainly made of more than 90% aggregate and about 5% asphalt hot mix, it has a high density and extremely high transportation costs. Taking the commonly used asphalt horseshoe ester macadam asphalt mixture (SM-13) on the road as an example, its density is about 2.46t / m 3 The weight of the upper layer of prefabricated pavement with a thickness of 4 cm for a single lane of one kilometer (3.75m) is 369 tons. The transportation of such a large weight seriously restricts the application scenarios and conditions of prefabricated hot-mix continuous asphalt pavement. In addition, the increase in the pavement elevation due to the 4 cm thick pavement has a great impact on the use of roadside basic ancillary facilities. It is necessary to groove the original pavement in advance and control the elevation for paving construction, which increases the construction links and prolongs the traffic closure time. In fact, it greatly weakens the advantages and characteristics of the prefabricated pavement in terms of rapid repair and timely opening of traffic.

[0006] Based on this, a prefabricated rollable composite thin layer asphalt pavement and its preparation method are studied. The composite thin layer asphalt pavement is curled into a thin layer shape with a small radius based on controlling a certain thickness and satisfying the bending mechanical tensile and compression characteristics, thereby greatly reducing the weight per unit area, increasing the flexible repair characteristics of the prefabricated pavement, and realizing carpet-style paving. Summary of the invention

[0007] Purpose of the invention: The technical problem to be solved by the present invention is to provide a prefabricated thin-layer asphalt pavement and a preparation method designed to meet the mechanical tensile and compression characteristics and achieve carpet-style paving based on controlling a certain thickness.

[0008] Technical solution: A prefabricated rollable composite thin-layer asphalt pavement, characterized in that the composite thin-layer asphalt pavement comprises a modified asphalt mixture layer A and a modified asphalt mixture layer B with different oil-to-stone ratios, and a first bonding layer, a tire base material layer and a second bonding layer located between the modified asphalt mixture layer A and the modified asphalt mixture layer B; the thickness of the composite thin-layer asphalt pavement is 2 to 2.5 cm, and the curling radius thereof is calculated by the following formulas (1) to (3):

[0009] L=α·R (1)

[0010]

[0011] Where: L is the arc length; ε is the strain; L x , L z are the arc lengths of the lower surface and neutral plane of the back layer after bending, respectively; R is the curling radius, mm; h is the pavement thickness, mm; α is the arc of the central angle;

[0012] The process of pavement bending is similar to the bending test process of asphalt mixture beam, that is, ε = ε B , the bending strain at the midpoint of the bottom surface of the specimen is:

[0013]

[0014] Where: ε B is the bending-tensile strain at the midpoint of the bottom surface; L′ is the span of the beam bending specimen, mm; h′ is the width of the beam specimen in the middle of the span, mm; d is the mid-span deflection, mm.

[0015] The prefabricated rollable composite thin-layer asphalt pavement of the present invention is designed to have a specific structural pavement composed of a modified asphalt mixture A, a first bonding layer, a tire base material layer, a second bonding layer and a modified asphalt mixture B from bottom to top on the basis of controlling the thickness to be 2 to 2.5 cm, so as to achieve the road performance of a thin layer; and a modified asphalt mixture A layer and a modified asphalt mixture B layer with different oil-stone ratios are used, combined with the mechanical analysis of pavement bending, to determine the minimum curling radius of the composite asphalt pavement under the condition of satisfying the mechanical tensile and compression characteristics, so as to achieve convenient transportation and carpet-style paving.

[0016] Furthermore, the raw materials used in the modified asphalt mixture layer A of the composite thin layer asphalt pavement include continuous densely mixed mineral material AC-5 with an oil-stone ratio of 5-6% and epoxy resin modified asphalt, which mainly bears the prefabricated curling compression force and the pavement driving function of the composite structure.

[0017] Furthermore, the modified asphalt mixture B used in the composite thin-layer asphalt pavement includes discontinuous-graded asphalt mineral aggregate SMA-5, TPS high-viscosity modified asphalt and fiber. The oil-stone ratio of the modified asphalt mixture B is 8-9%, and the amount of fiber added is 1.5-2.3‰ of the total content of discontinuous-graded asphalt mineral aggregate SMA-5 and TPS high-viscosity modified asphalt. It is located on the lower surface of the composite structure and bears the bending and tensile resistance during the curling process of the prefabricated pavement.

[0018] Furthermore, the materials used for the first bonding layer and the second bonding layer of the composite thin-layer asphalt pavement are fast-cracking high-viscosity modified emulsified asphalt.

[0019] Furthermore, the epoxy resin modified asphalt used in the composite thin layer asphalt pavement is prepared by the following steps: base asphalt and epoxy resin accounting for 28-30% of the asphalt mass are mixed at 180-200° C. for 20-30 minutes.

[0020] Furthermore, the TPS high-viscosity modified asphalt used in the composite thin-layer asphalt pavement is prepared by the following steps: heating the base asphalt to 175-180° C., adding a TPS modifier accounting for 14-16% of the mass of the base asphalt, and shearing for 50-60 minutes.

[0021] Furthermore, the material used for the base material layer of the composite thin-layer asphalt pavement includes polyester glass fiber cloth material or non-woven fabric.

[0022] The method for preparing the above-mentioned prefabricated rollable composite thin layer asphalt pavement of the present invention comprises the following steps:

[0023] (1) Brush oil on the upper base of the mold and pave the modified asphalt mixture B to form a modified asphalt mixture B layer;

[0024] (2) Spreading the second bonding layer material to form the second bonding layer, and simultaneously carrying out the paving of the tire base material layer;

[0025] (3) spreading the second bonding layer material to form a second bonding layer, and before the second bonding layer breaks, spreading the modified asphalt mixture A to form a modified asphalt mixture A layer;

[0026] (4) Roll the prefabricated pavement into a whole, cover the top surface with a non-stick film after cooling, unitize the prefabricated pavement, analyze the stress during its bending process, and determine the radius under certain thickness conditions based on the critical failure minimum bending strain and mid-span deflection of equations (1) to (3), and curl it into shape according to the radius.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the prefabricated rollable composite thin-layer asphalt pavement is thin and can be rolled into a small radius structure, which can not only greatly reduce the weight per unit area, but also increase the characteristics of high-quality flexible repair of the prefabricated pavement, with little impact on the pavement elevation, and does not require grooving and paving. It can quickly repair the pavement and harden the ground to achieve carpet-style paving; and the pavement's driving performance exceeds that of general thin-layer asphalt pavements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the precast curly pavement curling force analysis diagram;

[0029] Figure 2 The invention prefabricates a rollable composite thin-layer asphalt pavement structure;

[0030] Figure 3This is a bending test diagram of the prefabricated curled pavement of the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0032] The prefabricated rollable composite thin-layer asphalt pavement of the present invention is based on the road performance of thin-layer asphalt pavement. By unitizing the prefabricated pavement, the force analysis during its bending process is performed to form a prefabricated curved pavement with a small radius structure, so that the pavement can be quickly repaired and hardened while being easy to transport, and carpet-style paving is achieved. By unitizing the prefabricated pavement rolling process, it can be seen that during the rolling process of the pavement, the upper layer of the asphalt mixture is compressed and the lower layer of the asphalt mixture is stretched, as shown below Figure 1 shown.

[0033] like Figure 2 As shown, the composite thin layer asphalt pavement structure of the present invention comprises, from bottom to top, a modified asphalt mixture layer B, a first bonding layer, a tire base material layer, a second bonding layer and a modified asphalt mixture layer A. The thickness of the composite thin layer asphalt pavement structure is 2 to 2.5 cm.

[0034] The curling radius of the composite thin layer asphalt pavement is calculated by the following formula (1) to formula (3):

[0035] L=α·R (1)

[0036]

[0037] Where: L is the arc length; ε is the strain; L x , L z are the arc lengths of the lower surface and neutral plane of the back layer after bending, respectively; R is the curling radius, mm; h is the pavement thickness, mm; α is the arc of the central angle;

[0038] The process of pavement bending is highly similar to the process of asphalt mixture beam bending test (three-point bending), that is, ε = ε B , the bending strain at the midpoint of the bottom surface of the specimen is:

[0039]

[0040] Where: ε B is the bending-tensile strain at the midpoint of the bottom surface; L′ is the span of the beam bending specimen, mm; h′ is the width of the beam specimen in the middle of the span, mm; d is the mid-span deflection, mm.

[0041] The combined formula (2) and (3) can obtain the critical failure minimum bending strain and mid-span deflection of different curling radii and thicknesses, as shown in Tables 1 and 2.

[0042] Table 1 Minimum bending strain (ε) corresponding to different curling radii and thicknesses B )Require

[0043]

[0044] Table 2 Minimum mid-span deflection d (mm) at failure for different curling radii and thicknesses

[0045]

[0046]

[0047] Example 1

[0048] The prefabricated rollable composite thin-layer asphalt pavement of Example 1 is prepared by the following steps:

[0049] (1) Preparation of modified asphalt mixture A: The continuous densely mixed mineral material AC-5 and epoxy resin modified asphalt were heated to 190° C. according to an asphalt-to-stone ratio of 5.5%, and the modified asphalt mixture A was prepared by mixing;

[0050] (2) preparing modified asphalt mixture B: mixing discontinuous graded asphalt aggregate SMA-5, TPS modified asphalt and fiber at an asphalt-to-stone ratio of 8.5% and heating to 180° C., wherein the amount of fiber added is 2‰ of the total content of discontinuous graded asphalt aggregate SMA-5 and TPS high-viscosity modified asphalt, and mixing to obtain the modified asphalt mixture B;

[0051] The epoxy resin modified asphalt is prepared by the following steps: mixing the base asphalt and the epoxy resin accounting for 28-30% of the mass of the asphalt at 180-200° C. for 20-30 minutes.

[0052] TPS high-viscosity modified asphalt is prepared by the following steps: heating the base asphalt to 175-180° C., adding TPS modifier accounting for 14-16% of the mass of the base asphalt, and shearing for 50-60 minutes.

[0053] The material used for the first bonding layer and the second bonding layer of the present invention is fast-cracking high-viscosity modified emulsified asphalt, which is essentially the emulsified asphalt well known in the art, that is, a dispersed liquid in which asphalt and an emulsifier are combined through mechanical shear force and chemical action.

[0054] Continuous densely mixed aggregate AC-5 and discontinuously graded asphalt aggregate SMA-5 are designed according to the Technical Specifications for Preventive Maintenance of Highway Asphalt Pavement JTG_T5142-01-2021 and the Technical Specifications for Maintenance of Highway Asphalt Pavement JTG5142-2019, and the gradation range is shown in Table 3.

[0055] Table 3 Grading range of modified asphalt mixture mineral aggregate

[0056]

[0057] (3) Brush oil on the base of the double-sided guide rail mold with a thickness of 2.3 cm, and pave modified asphalt mixture B. The estimated compaction thickness is 1 cm, the Matsuura coefficient is 1.18, and the paving is even without compaction;

[0058] (4) Spreading high-viscosity modified emulsified asphalt to form the first bonding layer, and simultaneously laying the polyester glass fiber cloth of the tire base material layer;

[0059] (5) Spreading high-viscosity modified emulsified asphalt to form a second bonding layer, and before the emulsion breaks, spreading modified asphalt mixture A to form a modified asphalt mixture A layer;

[0060] (4) Roll the steel into a finished product, cover the top surface with a non-stick film after cooling, and conduct a low-temperature beam bending test according to T 0715-2011. According to the critical failure minimum bending strain and mid-span deflection in Tables 1 and 2 obtained by equations (1) to (3), determine the radius under the condition of a thickness of 2.3 cm, and then roll it into shape.

[0061] The specific experiment is as follows: standard test piece is formed, length: 250mm±2mm, width: 30mm±2mm, height is the thickness of the composite structure, that is, the thickness of the prefabricated curled pavement is 23mm±2mm, test temperature is -10℃, other environmental settings, loading rate and other test steps are the same as the standard test. The test results are shown in Table 4, and the experimental diagram is shown in Figure 3 .

[0062] Table 4 Composite structure beam bending test results (-10℃)

[0063]

[0064] According to the mechanical indicators calculated from Table 1 and Table 2, when the thickness of the curled pavement is 23 mm and the curling radius is 875 mm, the minimum bending strain (ε B ) is 1297.1, the critical failure deflection d (mm) is 2.88; when the radius is 1000mm, the minimum bending strain (ε B ) is 1136.9, and the critical failure deflection d (mm) is 2.53. As shown in Table 8, the minimum bending strain (ε B ) is 1341.1, and the critical failure deflection d (mm) is 297. It can be seen that the pavement meets the technical requirements of curling with a radius of 875 mm, but considering the reliability and the comprehensive variability value, it is judged that the curling requirement with a radius of 1000 mm is met, that is, the curling performance index of the prefabricated curled pavement in Example 1 of the present invention is: thickness 2.3 cm, curling diameter 2 m.

[0065] In addition, the road performance of the modified asphalt mixture A prepared in Example 1 is shown in Table 5 below.

[0066] Table 5 Performance indexes of modified asphalt mixture A

[0067]

[0068]

[0069] It can be seen from Table 5 that the above asphalt mixture fully meets the road performance requirements, has good strength, excellent water damage resistance and low temperature performance, and anti-skid performance exceeds the standard value, and can completely replace ordinary thin-layer asphalt pavement.

[0070] The performance test results of epoxy resin modified asphalt and TPS high viscosity modified asphalt are shown in Tables 6 and 7 below, and the emulsified asphalt used is shown in Table 8.

[0071] Table 6 Technical indicators of epoxy resin modified asphalt

[0072]

[0073] Table 7 Test results of technical indicators of TPS high viscosity modified asphalt

[0074]

[0075] Table 8 Technical requirements for emulsified asphalt

[0076]

[0077]

[0078] From the above tests, it can be seen that the prefabricated curled composite thin layer asphalt pavement of the present invention fully meets the road performance of the current thin layer asphalt pavement, and can meet the curling requirements of a radius of 1 meter. The overall thickness is about 2.3 cm, which is significantly lighter than the traditional 4 cm, and enhances the flexibility of rapid repair. That is, the comprehensive density of the prefabricated curled thin layer asphalt mixture of the present invention is 2.44 t / m 3 With a thickness of 2.3, the weight of a single lane (3.75m) of one kilometer is about 212 tons, which is 42.5% lighter than the prefabricated pavement thickness of 4cm. The weight per square meter is only 56kg, which is lighter than the traditional cold patch asphalt mixture and has better repair quality. Due to its good anti-skid and upper layer road performance, it can be used as a hardened road surface in special situations such as emergency disaster relief to ensure the passage of vehicles.

[0079] In addition to the above embodiments, in the prefabricated rollable composite thin-layer asphalt pavement of the present invention, the oil-stone ratio of the modified asphalt mixture layer A can also be 5-6%. The oil-stone ratio of the modified asphalt mixture layer B can also be 8-9%, and the amount of fiber added can also be 1.5-2.3‰ of the total content of the discontinuous graded asphalt mineral aggregate SMA-5 and TPS high-viscosity modified asphalt. The material used for the tire base material layer can also be non-woven fabrics, geotextiles, etc.

Claims

1. A prefabricated rollable composite thin layer asphalt pavement, characterized in that: The composite thin-layer asphalt pavement comprises a modified asphalt mixture layer A and a modified asphalt mixture layer B with different oil-to-stone ratios, and a first bonding layer, a tire base material layer and a second bonding layer located between the modified asphalt mixture layer A and the modified asphalt mixture layer B; the thickness of the composite thin-layer asphalt pavement is 2 to 2.5 cm, and the curling radius thereof is calculated by the following formulas (1) to (3): L=α·R (1) Where: L is the arc length; ε is the strain; L x , L z are the arc lengths of the lower surface and neutral plane of the back layer after bending, respectively; R is the curling radius, mm; h is the pavement thickness, mm; α is the arc of the central angle; The process of pavement bending is similar to the bending test process of asphalt mixture beam, that is, ε = ε B , the bending strain at the midpoint of the bottom surface of the specimen is: Where: ε B is the bending-tensile strain at the midpoint of the bottom surface; L′ is the span of the beam bending specimen, mm; h′ is the width of the beam specimen in the middle of the span, mm; d is the mid-span deflection, mm.

2. The prefabricated rollable composite thin layer asphalt pavement according to claim 1, characterized in that: The raw materials used in the modified asphalt mixture layer A include continuous densely mixed mineral material AC-5 with an oil-stone ratio of 5-6% and epoxy resin modified asphalt.

3. The prefabricated rollable composite thin layer asphalt pavement according to claim 1, characterized in that: The modified asphalt mixture B comprises discontinuously graded asphalt aggregate SMA-5, TPS high-viscosity modified asphalt and fiber. The oil-stone ratio of the modified asphalt mixture B is 8-9%, and the added amount of fiber is 1.5-2.3‰ of the total content of discontinuously graded asphalt aggregate SMA-5 and TPS high-viscosity modified asphalt.

4. The prefabricated rollable composite thin layer asphalt pavement according to claim 1, characterized in that: The materials used for the first bonding layer and the second bonding layer are fast-cracking high-viscosity modified emulsified asphalt.

5. The prefabricated rollable composite thin layer asphalt pavement according to claim 2, characterized in that: The epoxy resin modified asphalt is prepared by the following steps: mixing the base asphalt and the epoxy resin accounting for 28-30% of the mass of the asphalt at 180-200° C. for 20-30 minutes.

6. The prefabricated rollable composite thin layer asphalt pavement according to claim 3, characterized in that: The TPS high-viscosity modified asphalt is prepared by the following steps: heating the base asphalt to 175-180° C., adding a TPS modifier accounting for 14-16% of the mass of the base asphalt, and shearing for 50-60 minutes.

7. The prefabricated rollable composite thin layer asphalt pavement according to claim 1, characterized in that: The material used for the tire base material layer includes polyester glass fiber cloth material or non-woven fabric.

8. A method for preparing the prefabricated rollable composite thin layer asphalt pavement according to claim 1, characterized in that The steps include: (1) Brush oil on the upper base of the mold and pave the modified asphalt mixture B to form a modified asphalt mixture B layer; (2) Spreading the second bonding layer material to form the second bonding layer, and simultaneously carrying out the paving of the tire base material layer; (3) spreading the second bonding layer material to form a second bonding layer, and before the second bonding layer breaks, spreading the modified asphalt mixture A to form a modified asphalt mixture A layer; (4) Roll the prefabricated pavement into a whole, cover the top surface with a non-stick film after cooling, unitize the prefabricated pavement, analyze the stress during its bending process, and determine the radius under certain thickness conditions based on the critical failure minimum bending strain and mid-span deflection of equations (1) to (3), and curl it into shape according to the radius.

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