A method of asphalt road construction

Abstract

The application provides an asphalt road construction method, relates to the technical field of highway engineering construction, and is suitable for old road reconstruction, newly-built main roads and slow-moving systems and the like. The core innovation of the method is that a technical system of 'layered differentiated structure design + stress absorption layer strengthening + multi-dimensional dynamic quality control' is adopted, through key steps of base pre-treatment, layered paving, stress absorption layer setting, precise mixing and transportation, collaborative rolling and joint optimization, and in combination with environmental protection construction measures. The method clearly defines process parameters of the whole process of mixing, transportation, paving and compaction of asphalt mixture, adopts a collaborative rolling mode of double steel wheels + rubber-tired road rollers, and cooperates with hot joint treatment technology, so that the compaction degree of the road surface is ensured to be greater than or equal to 96%, the flatness is less than or equal to 3mm, and the anti-skid structure depth is greater than or equal to 0.55mm. The construction efficiency of the method is improved by more than 20%, the service life of the road surface is prolonged by 3-5 years, the dust and noise in the construction process meet the standards, the method is suitable for secondary road and slow-moving system construction, and has remarkable technical, economic and environmental protection values.

Description

Technical Field

[0001] This invention relates to the field of highway engineering construction technology, specifically to an asphalt road construction method applicable to secondary highways, slow traffic systems, and old road reconstruction, and is particularly suitable for the construction and upgrading of asphalt pavements in humid climates and complex terrain areas. Background Technology

[0002] Asphalt pavement is widely used in highway construction due to its advantages such as good smoothness, driving comfort, and convenient construction. However, traditional construction methods have many drawbacks: Reflective cracks are prone to occur during the reconstruction of old roads: insufficient bonding between the old cement concrete pavement and the newly laid asphalt layer makes it easy for reflective cracks to appear under temperature stress and load, which affects the service life of the pavement. Severe segregation of the mixture: Insufficient mixing time, improper insulation during transportation, and fluctuations in paving speed lead to an imbalance in the gradation of the mixture, resulting in problems such as white aggregate and insufficient compaction in some areas; Unstable compaction quality: unreasonable combination of compaction equipment and poor temperature control lead to poor road surface smoothness and weak resistance to water damage; Insufficient environmental performance: Dust and noise pollution during construction, and waste of resources due to the random disposal of leftover mixture; Poor scenario adaptability: The structure is not designed to meet the different needs of old road renovation, new main road construction, and slow traffic system, resulting in insufficient versatility.

[0003] Existing construction methods are insufficient to simultaneously address the synergistic optimization of crack resistance, smoothness, durability, and environmental friendliness. There is an urgent need for an asphalt road construction method that is adaptable to multiple scenarios, has controllable quality, and is environmentally friendly and efficient.

[0004] Therefore, those skilled in the art provide an asphalt road construction method to solve the problems mentioned in the background art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an asphalt road construction method that solves the problem of simultaneously optimizing crack resistance, smoothness, durability, and environmental friendliness, which is difficult to achieve with existing construction methods.

[0006] To achieve the above objectives, the present invention provides the following technical solution: An asphalt road construction method, applicable to the reconstruction of old roads, construction of new main roads, and asphalt pavement construction of slow-traffic systems, includes the following steps: Step 1: Base layer pretreatment For old cement concrete pavement, treat defects (such as crack grouting and bottom void treatment). For new roadbed, lay a 15cm unscreened crushed stone subbase, an 18cm subbase of 3.5%-4.5% cement-stabilized graded crushed stone, and an 18cm top base of 4.5%-5.5% cement-stabilized graded crushed stone, ensuring that the base course flatness is ≤5mm / 3m and the compaction degree is ≥97%. Step 2: Laying the stress-absorbing layer A 2cm AC-10 stress-absorbing layer is laid between the base course and the asphalt surface course, using SBS modified asphalt with a spreading rate of 1.6-2.0 kg / m². Simultaneously, 8-12mm single-particle-size premixed gravel is spread at a spreading rate of 10 kg / m², and then compacted 2-4 times with a pneumatic tire roller. Step 3: Asphalt Mixture Preparation 5% SBS modified asphalt (composed of 95% No. 70 Grade A road petroleum asphalt + 5% SBS modifier) ​​is mixed with basalt coarse aggregate, clean fine aggregate and mineral powder. It is dry-mixed for 5-10 seconds and wet-mixed for 45-60 seconds in an intermittent mixing machine. The temperature of the modified asphalt mixture leaving the factory is controlled at 170-185℃ and shall not exceed 195℃. Step 4: Mixture transportation and paving Transport using dump trucks with insulated tarpaulins, ensuring the temperature upon arrival is not lower than 160℃; preheat the paver to above 100℃, and pave in echelon at a speed of 2-3m / min. The 5cm modified AC-20C lower layer is guided and leveled using steel wire ropes, and the 4cm modified AC-13C upper layer is controlled using non-contact balance beams, with a loose paving coefficient of 1.15-1.35. Step 5: Collaborative compaction Following the principles of "high temperature, close following, slow compaction, high frequency, and low amplitude," the initial compaction uses a steel wheel roller for 1-2 static compactions at a speed of 1.5-2 km / h; the secondary compaction uses a double steel wheel vibratory roller for 2-4 compactions plus a rubber-tired roller for 2 compactions at a speed of 3-5 km / h; and the final compaction uses a steel wheel roller for 2 static compactions at a speed of 3-6 km / h. The final compaction temperature should not be lower than 110℃. Step Six: Seam Treatment Longitudinal seams are heat-sealed with an overlap of 30-60mm, and transverse seams are vertical flat seams. After cutting and cleaning the seams, apply tack coat. The upper and lower seams are staggered by more than 200mm. Step Seven: Quality Inspection and Traffic Control According to the specifications, the compaction degree, smoothness, texture depth and other indicators are tested, and the road surface is opened to traffic after the temperature is below 50℃.

[0007] Furthermore, the base treatment for old road reconstruction in step one also includes: roughening the old cement concrete pavement, removing laitance, and then spraying modified emulsified tack coat asphalt at a dosage of 0.4 L / m. 2 ; The compaction degree of the base course of newly built main roads shall be controlled according to the heavy compaction standard, with the subbase course ≥95% and the upper base course ≥97%.

[0008] Furthermore, in step three, the gradation of the asphalt mixture meets the requirements of JTGF40-2004 specification, the porosity of AC-13C mixture is 3-5%, the Marshall stability is ≥8kN, the aggregate porosity of AC-20C mixture is 12-14%, and the asphalt saturation is 65-75%.

[0009] Furthermore, in step four, the transport vehicles must undergo temperature testing upon arrival, and modified asphalt mixtures with a temperature below 160°C must be discarded. The height of the mixture on both sides of the paver's auger spreader should not be less than 2 / 3 of the spreader height to avoid segregation during paving.

[0010] Furthermore, in step five, the vibration frequency of the double steel drum roller is 35-50Hz and the amplitude is 0.3-0.8mm, the tire pressure of the rubber-tired roller is ≥0.55MPa, the steel drum is sprayed with water in a mist to prevent sticking during the rolling process, and water is prohibited from being sprayed on the rubber drum.

[0011] Furthermore, the transverse joint treatment in step six is ​​as follows: before paving, the loose parts are cut off, and after cleaning, tack coat is applied. The newly laid mixture overlaps by 50-100mm. During compaction, the mixture is first compacted transversely and then longitudinally to ensure a smooth joint.

[0012] Furthermore, in the construction of the slow-traffic system, the newly built section adopts a structure of "3cm black AC-10 lower layer + 3cm colored AC-10 upper layer", the base layer is 15cm of 4.5%-5.5% cement-stabilized graded crushed stone, and the subbase is 15cm of 3.5%-4.5% cement-stabilized graded crushed stone.

[0013] Furthermore, the quality acceptance indicators include: compaction degree ≥96% (Marshall test standard density), flatness ≤3mm / 3m, structural depth ≥0.55mm, lateral force coefficient SFC60 ≥54, and permeability coefficient ≤300mL / min.

[0014] This invention provides a method for constructing asphalt roads. It has the following beneficial effects: 1. This invention provides an asphalt road construction method. The stress-absorbing layer effectively disperses the stress of the base layer, reduces the incidence of reflective cracks in old road reconstruction by 80%, extends the service life of the pavement by 3-5 years, significantly improves crack resistance, avoids segregation of the mixture through full-process parameter control, achieves 100% compliance rate for compaction, and has a smoothness that exceeds the standard requirements, thus effectively improving driving comfort.

[0015] 2. This invention provides an asphalt road construction method with differentiated structural design to adapt to old road renovation, new main road construction, and slow traffic system; colored asphalt surface layer to meet landscape requirements; water spraying to reduce dust; low-noise equipment; construction dust and noise meet standards; residual mixture is recycled, reducing resource waste by 30%.

[0016] 3. This invention provides an asphalt road construction method that adopts a tiered paving + synergistic compaction mode, which increases the daily paving volume per lane by 20% and shortens the construction period by 15-20%. The synergistic effect of SBS modified asphalt and basalt aggregate results in excellent pavement resistance to water damage and skid resistance, adaptability to humid climates, and effective enhancement of durability. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit the invention.

[0018] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0020] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0021] This invention provides an asphalt road construction method applicable to the reconstruction of old roads, the construction of new main roads, and the construction of asphalt pavements for slow-traffic systems, comprising the following steps: Step 1: Base layer pretreatment Old road renovation: Inspect the old cement concrete pavement for defects such as cracks and voids at the bottom of the slabs. Cracks are treated with pressure grouting, and voided areas are reinforced with cement grout. After roughening the pavement, remove the laitance and spray modified emulsified tack coat asphalt at a rate of 0.4 L / m. 2 ; New roadbed: Construction shall be carried out in the order of "subbase → subbase → upper base". The subbase shall be made of 15cm unscreened crushed stone, the subbase shall be made of 18cm of 3.5%-4.5% cement-stabilized graded crushed stone, and the upper base shall be made of 18cm of 4.5%-5.5% cement-stabilized graded crushed stone. After each layer is constructed, the compaction and flatness shall be tested. Only after passing the test can the next layer be constructed.

[0022] Step 2: Laying the stress-absorbing layer Material preparation: Use SBS modified asphalt and premixed gravel with a single particle size of 8-12mm to ensure that the crushed stone is clean, dry and unweathered; Construction operation: The synchronous chip seal spreader travels at a constant speed of 3-5 km / h, sprays hot asphalt at a temperature of 170-180℃, and spreads it at a rate of 1.6-2.0 kg / m². Simultaneously, it spreads crushed stone at a rate of 10 kg / m², achieving a coverage rate of 65-75%. Compaction and curing: The pneumatic tire roller closely follows the spreader to compact the asphalt 2-4 times at a speed of 2-3 km / h to ensure that the crushed stone and asphalt are firmly bonded and there is no loosening.

[0023] Step 3: Asphalt Mixture Preparation Raw material requirements: SBS modified asphalt penetration 30-60, softening point ≥60℃; coarse aggregate is basalt, crushing value ≤30%, flaky and needle-like particle content ≤20%; fine aggregate mud content ≤5%, sand equivalent ≥50%; mineral powder moisture content ≤1%; Mixing process: The cold aggregate bins of the intermittent mixing plant are fed with aggregates according to the gradation ratio. The aggregate drying temperature is 160-180℃, and the modified asphalt heating temperature is 160-170℃. Dry mixing takes 5-10 seconds, and wet mixing takes 45-60 seconds to ensure that the mixture is evenly coated and free of white spots. Quality control: The gradation, asphalt-aggregate ratio and Marshall index of the mixture are tested every shift. The factory temperature is 170-185℃. Overheated or caking mixtures are discarded.

[0024] Step 4: Mixture transportation and paving Transportation guarantee: 22m³ dump trucks are used, with a thin layer of release agent applied to the floor of the truck bed and an insulating tarpaulin covering the top; transportation time ≤30min, and the temperature upon arrival is not lower than 160℃; Paving preparation: Preheat the paver screed to above 100℃, adjust the loose paving coefficient to 1.15-1.35, use steel wire rope to guide the elevation control of the lower layer, and use a non-contact balance beam for the upper layer; Paving operation: Two pavers work in a team, with a spacing of 10-20m, a paving speed of 2-3m / min, and an overlap width of 30-60mm, avoiding interruptions in the middle; during the paving process, manual cleaning of local segregated mixture and respreading of fine material are required.

[0025] Step 5: Collaborative compaction Initial compaction: Steel wheel roller static compaction 1-2 times, speed 1.5-2km / h, compaction temperature not lower than 150℃, compaction from the outside to the center, superelevation sections compaction from low to high; Secondary compaction: Vibratory compaction with a double-drum roller for 2-4 passes at a frequency of 35-50Hz and an amplitude of 0.3-0.8mm, followed by compaction with a rubber-tired roller for 2 passes at a speed of 3-5km / h, achieving a compaction degree of over 96%. Final compaction: Two static compaction passes with a steel wheel roller at a speed of 3-6 km / h, with a final compaction temperature of not less than 110℃, to eliminate wheel tracks and ensure a smooth road surface.

[0026] Step Six: Seam Treatment Longitudinal joint: Hot joint is used. After the front section is paved, a 30-60mm gap is left uncompacted. When the rear section is paved, it overlaps the front section. The joint is compacted across the gap to eliminate the joint marks. Transverse joints: At the end of the paving, use a cutting machine to cut the joints, remove loose parts, and apply tack coat; the newly paved mixture overlaps by 50-100mm, first roll transversely with a road roller traveling transversely, rolling a width of 150mm, and then roll longitudinally to ensure the joints are smooth.

[0027] Step Seven: Quality Inspection and Traffic Control Testing indicators: compaction degree ≥96%, flatness ≤3mm, structural depth ≥0.55mm, transverse force coefficient SFC60 ≥54, permeability coefficient ≤300mL / min; Traffic control: Traffic will be opened once the road surface temperature is below 50°C. Construction vehicles are prohibited from turning around or stopping on the uncooled road surface.

[0028] Implementation Case: This implementation case is a reconstruction project of a section of provincial highway S254. The total length of the route is 29.779km, of which 13.627km is the old road reconstruction section, 16.152km is the newly built main road section, and the total length of the slow traffic system is 29.779km. The old road renovation adopts the structure of "old cement pavement treatment + 2cm AC-10 stress absorption layer + 5cm AC-20C lower layer + 4cm AC-13C surface layer". The newly built main road adopts the structure of "15cm unscreened crushed stone subbase + 18cm cement-stabilized graded crushed stone subbase + 18cm cement-stabilized graded crushed stone upper base + 5cm AC-20C intermediate layer + 4cm AC-13C surface layer". The newly built section of the slow traffic system adopts the structure of "15cm cement-stabilized graded crushed stone subbase + 15cm cement-stabilized graded crushed stone base + 3cm AC-10 lower layer + 3cm colored AC-10 upper layer".

[0029] ① Construction preparation Equipment configuration: intermittent asphalt mixing plant, 2 ABG423 pavers, 2 STR130 double drum rollers, 1 SPR260E rubber-tired roller, 15 22m³ dump trucks, and 1 synchronous chip seal spreader. Material preparation: SBS modified asphalt (compliant with JTGF40-2004 standard), basalt coarse aggregate, clean river sand, mineral powder. The mix design should be completed in advance, with an asphalt-aggregate ratio of 5.0% for AC-13C and 4.8% for AC-20C. Technical preparation: Provide technical instructions to construction personnel and clarify the process parameters for each procedure; complete the construction of a 200m test section to determine key parameters such as the loose paving coefficient of 1.25 and the number of compaction passes.

[0030] ② Implementation process Base course pretreatment: Epoxy resin grouting is used for cracks in old roads, and the grouting pressure for voids at the bottom of the slab is 0.3-0.5MPa. The base course of the new roadbed is laid and compacted in layers. After the compaction degree is qualified, tack coat is sprayed. Stress-absorbing layer construction: The synchronous chip seal spreader travels at a constant speed, with asphalt spread rate of 1.8 kg / m² and chip spread rate of 10 kg / m². The pneumatic tire roller compacts the surface three times, and the chip bond rate is tested to be ≥95%. Mixing and transportation of the mixture: The mixing machine batches the materials according to the mix proportion, dry mixing for 8 seconds and wet mixing for 50 seconds, the factory temperature is 175℃, the transport vehicles are covered with thermal tarpaulins, the temperature upon arrival at the site is 165℃, and there are ≥5 vehicles waiting in front of the paver. Paving and compaction: Pavers operate in echelon formation at a speed of 2.5 m / min. The lower layer is guided by steel wire ropes, and the upper layer is controlled by a balance beam. The initial compaction temperature is 155℃. The secondary compaction is carried out by 3 passes of double steel wheel vibratory compaction and 2 passes of rubber wheel compaction. The final compaction temperature is 115℃. Joint treatment: Longitudinal joints overlap by 40mm, transverse joints are cut and then coated with tack coat, overlap by 80mm, and after rolling, the flatness is checked with a 3m straightedge and is ≤2mm. Quality acceptance: Core drilling test showed a compaction degree of 97.5%, a structural depth of 0.62 mm, and a lateral force coefficient SFC60=62. All indicators met the requirements. The road surface was opened to traffic after cooling to 45℃. Implementation effect

[0031] The compaction degree, flatness, and anti-slip performance are all better than the requirements of JTGF80-1-2004 standard, and there are no defects such as reflective cracks and segregation; The daily paving volume per section reaches 12,000 square meters, which is 25% higher than the traditional method, and the total construction period is shortened by 18 days; The construction dust concentration was 0.3 mg / m³, and the noise level was 72 dB(A), which met environmental protection standards. One year after the road opened to traffic, the road surface was undamaged and free of water accumulation, maintaining good smoothness and providing excellent driving comfort.

[0032] The following points should be noted in this article: 1. The embodiments disclosed herein only relate to the structures involved in the embodiments disclosed herein; other structures may refer to general designs.

[0033] 2. Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0034] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for constructing asphalt roads, characterized in that, This method is applicable to the reconstruction of old roads, the construction of new main roads, and the construction of asphalt pavement for slow-traffic systems, and includes the following steps: Step 1: Base layer pretreatment For the old cement concrete pavement, defects are treated. For the newly built roadbed, a 15cm unscreened crushed stone subbase, an 18cm subbase of 3.5%-4.5% cement-stabilized graded crushed stone, and an 18cm upper base of 4.5%-5.5% cement-stabilized graded crushed stone are laid in sequence to ensure that the flatness of the base layer is ≤5mm / 3m and the compaction degree is ≥97%. Step 2: Laying the stress-absorbing layer A 2cm AC-10 stress-absorbing layer is laid between the base course and the asphalt surface course, using SBS modified asphalt with a spreading rate of 1.6-2.0 kg / m². Simultaneously, 8-12mm single-particle-size premixed gravel is spread at a spreading rate of 10 kg / m², and then compacted 2-4 times with a pneumatic tire roller. Step 3: Asphalt Mixture Preparation 5% SBS modified asphalt is mixed with basalt coarse aggregate, clean fine aggregate and mineral powder. It is dry-mixed for 5-10 seconds and wet-mixed for 45-60 seconds in an intermittent mixing machine. The temperature of the modified asphalt mixture leaving the plant is controlled at 170-185℃ and shall not exceed 195℃. Step 4: Mixture transportation and paving Transport using dump trucks with insulated tarpaulins, ensuring the temperature upon arrival is not lower than 160℃; preheat the paver to above 100℃, and pave in echelon at a speed of 2-3m / min. The lower layer is guided and leveled using steel wire ropes, while the upper layer is controlled using non-contact balance beams, with a loose paving coefficient of 1.15-1.

35. Step 5: Collaborative compaction Following the principles of "high temperature, close following, slow pressing, high frequency, low amplitude", the initial pressing, secondary pressing, and final pressing should be completed with a final rolling temperature of no less than 110℃. Step Six: Seam Treatment Longitudinal seams are heat-sealed with an overlap of 30-60mm, and transverse seams are vertical flat seams. After cutting and cleaning the seams, apply tack coat. The upper and lower seams are staggered by more than 200mm. Step Seven: Quality Inspection and Traffic Control According to the specifications, the compaction degree, smoothness, texture depth and other indicators are tested, and the road surface is opened to traffic after the temperature is below 50℃.

2. The asphalt road construction method according to claim 1, characterized in that, The first step of the old road reconstruction base treatment also includes: roughening the old cement concrete pavement, removing the laitance, and then spraying modified emulsified tack coat asphalt at a rate of 0.4 L / m. 2 ; The compaction degree of the base course of newly built main roads shall be controlled according to the heavy compaction standard, with the subbase course ≥95% and the upper base course ≥97%.

3. The asphalt road construction method according to claim 1, characterized in that, In step three, the asphalt mixture gradation meets the requirements of JTGF40-2004 specification. The AC-13C mixture has a void ratio of 3-5% and a Marshall stability of ≥8kN. The AC-20C mixture has a mineral aggregate void ratio of 12-14% and an asphalt saturation of 65-75%.

4. The asphalt road construction method according to claim 1, characterized in that, In step four, the transport vehicles must undergo temperature testing upon arrival, and modified asphalt mixtures with a temperature below 160°C must be discarded. The height of the mixture on both sides of the paver's auger spreader should not be less than 2 / 3 of the spreader height to avoid segregation during paving.

5. The asphalt road construction method according to claim 1, characterized in that, In step five, the vibration frequency of the double steel drum roller is 35-50Hz and the amplitude is 0.3-0.8mm. The tire pressure of the rubber-tired roller is ≥0.55MPa. During the rolling process, the steel drum is sprayed with water in a mist to prevent sticking, while water is prohibited from being sprayed on the rubber drum.

6. The asphalt road construction method according to claim 1, characterized in that, The transverse joint treatment in step six is ​​as follows: before paving, cut off the loose parts, clean and apply tack coat, overlap the newly laid mixture by 50-100mm, and compact it first transversely and then longitudinally to ensure the joint is smooth.

7. The asphalt road construction method according to claim 1, characterized in that, During the construction of the slow-traffic system, the newly built section adopts a structure of "3cm black AC-10 lower layer + 3cm colored AC-10 upper layer". The base layer is 15cm of 4.5%-5.5% cement-stabilized graded crushed stone, and the subbase is 15cm of 3.5%-4.5% cement-stabilized graded crushed stone.

8. The asphalt road construction method according to claim 1, characterized in that, The quality acceptance indicators include: compaction degree ≥96%, flatness ≤3mm / 3m, structural depth ≥0.55mm, lateral force coefficient SFC60 ≥54, and permeability coefficient ≤300mL / min.