CN112030657A

CN112030657A - Asphalt mixture compacting process and pavement construction method

Info

Publication number: CN112030657A
Application number: CN202010920455.0A
Authority: CN
Inventors: 白俊林; 郭永伟; 尹世光; 王洪宇; 王定贵; 孙启媛; 陈磊; 李勇; 李耀; 孟士杰
Original assignee: CCCC First Highway Engineering Co Ltd; Third Engineering Co Ltd of Highway Engineering Bureau of CCCC
Current assignee: CCCC First Highway Engineering Co Ltd; Third Engineering Co Ltd of Highway Engineering Bureau of CCCC
Priority date: 2020-09-04
Filing date: 2020-09-04
Publication date: 2020-12-04

Abstract

The invention provides an asphalt mixture compacting process and a pavement construction method, which relate to the technical field of highway construction, and the asphalt mixture compacting process comprises the following steps: carrying out primary pressing on the paved asphalt mixture by using a rubber-tyred road roller; re-pressing the asphalt mixture by using a rubber-wheel road roller or a double-steel-wheel road roller; and finally pressing the asphalt mixture by using a double-steel-wheel road roller. The combination of the rolling modes adopted by the process can avoid fine cracks in the primary pressing process, and mucilage formed by asphalt, mineral powder, fine aggregate and the like in the mixture can float upwards, so that the upper surface is more compact, and the waterproofness is better.

Description

Asphalt mixture compacting process and pavement construction method

Technical Field

The invention relates to the technical field of highway construction, in particular to an asphalt mixture compacting process and a pavement construction method.

Background

The compaction operation of the asphalt mixture is an important process in the construction of the asphalt concrete pavement, and the compaction quality of the asphalt mixture is very important for ensuring the construction quality of the asphalt pavement.

In the prior art, after paving of the asphalt mixture is completed, a double-steel-wheel road roller is adopted to perform primary pressing on the asphalt mixture. However, during the initial pressing, a transition phenomenon occurs in which the mix on the front side of the drum is subjected to a pressure and then moves laterally. The compaction mode can cause cracks on the road surface, influence the construction quality of the road surface and further influence the service life of the road surface.

Disclosure of Invention

The invention aims to provide an asphalt mixture compacting process and a pavement construction method, which solve the technical problems that the initial pressure in the prior art possibly causes cracks on the pavement, influences the construction quality of the pavement and further influences the service life of the pavement.

The invention provides an asphalt mixture compacting process, which comprises the following steps:

carrying out primary pressing on the paved asphalt mixture by using a rubber-tyred road roller;

re-pressing the asphalt mixture by using a rubber-wheel road roller or a double-steel-wheel road roller;

and finally pressing the asphalt mixture by using a double-steel-wheel road roller.

Further, before the step of rolling the paved asphalt mixture by using the rubber-tyred roller, the method further comprises the following steps: and (3) coating the anti-bonding agent on the tire of the rubber-tyred road roller.

Further, in the step of initial pressing, a rubber-tyred roller is used for kneading and pressing the asphalt mixture, wherein the rolling speed is 2.5-3.0 km/h; in the step of repressing, when a rubber-tyred roller is selected to repress the asphalt mixture, kneading and compacting the asphalt mixture by using the rubber-tyred roller at a rolling speed of 3.5-4.0 km/h; in the final pressing step, a double-steel-wheel road roller is used for respectively carrying out static pressing on the asphalt mixture until no tire trace exists, and the rolling speed is 3.0-4.0 km/h.

Furthermore, an automatic water spraying device is arranged on the double-steel-wheel road roller; the automatic water spraying device is used for spraying water mist to the tire.

Furthermore, the temperature of the asphalt mixture is not lower than 150 ℃ during initial pressing, and is not lower than 90 ℃ during re-pressing.

Further, in the step of re-pressing, the tire inflation pressure of the rubber-tyred roller is not less than 0.55MPa when in a cold state and not less than 0.6MPa after heating.

Further, in the step of repressing, when a double-steel-wheel road roller is used for repressing the asphalt mixture, the double-steel-wheel road roller is used for carrying out vibration-compaction on the asphalt mixture, wherein the vibration frequency is not less than 35-50 Hz, and the amplitude is not less than 0.3-0.8 mm.

Furthermore, the invention also provides a pavement construction method which comprises the asphalt mixture compacting process.

Further, the pavement construction method comprises the following steps:

preparing a lower bearing layer and cleaning the lower bearing layer;

carrying out test mixing on the asphalt mixture, and constructing in a test section;

uniformly mixing the asphalt mixture according to the mixing test result;

transporting the asphalt mixture to a road surface to be constructed and paving the asphalt mixture;

and compacting the asphalt mixture by using an asphalt mixture compacting process.

Further, in the step of transporting the asphalt mixture to the road surface to be constructed and paving the asphalt mixture, the temperature of the asphalt mixture during paving is not lower than 160 ℃.

In the process of using the asphalt mixture compaction process provided by the invention, the rubber-tyred roller can change inflation pressure according to actual requirements so as to change the grounding pressure, namely the pressure of the rubber-tyred roller on the asphalt mixture can be greater than the pressure of the double-steel-tyred roller on the asphalt mixture. In addition, in the compaction process, the rubber-tyred roller can be used for kneading, namely, the rubber-tyred roller has a kneading effect, so that particles in a compaction layer can be embedded without being damaged, and the rubber-tyred roller is uniform and compact. And secondly, re-pressing the asphalt mixture by using a rubber-wheel road roller or a parallel-bar road roller, finally performing final pressing and surface compacting on the asphalt mixture by using a double-steel-wheel road roller, and repeating the compacting step, so that the compactness and the uniformity of the asphalt mixture are further improved.

According to the combination of the rolling modes adopted by the process, fine cracks can be avoided in the initial pressing process, mucilage formed by asphalt, mineral powder, fine aggregates and the like in the mixture can float upwards, the upper surface is more compact, and the waterproofness is better.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a block diagram illustrating steps in a process for compacting asphalt mixtures according to an embodiment of the present invention;

fig. 2 is a block diagram illustrating steps of a pavement construction method according to an embodiment of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

FIG. 1 is a block diagram illustrating steps in a process for compacting asphalt mixtures according to an embodiment of the present invention; as shown in FIG. 1, the asphalt mixture compacting process provided by the invention comprises the following steps:

The anti-caking agent is an oil-water mixture, and a mixture of vegetable oil and water can be selected, so that diesel oil is not selected for mixing.

Specifically, before rolling by the rubber-tyred roller, the anti-bonding agent is sprayed on the waterproof cloth paved on the ground, and then the rubber-tyred roller is made to walk on the waterproof cloth until the tires are fully coated with the anti-bonding agent. In addition, in the process of initial pressing, the tire of the rubber-tyred road roller needs to be repaired and brushed.

In the construction process, the asphalt mixture can generate a wheel sticking phenomenon under the condition of high temperature, so that the pavement is uneven and flat. The anti-sticking agent is coated, so that the condition of a wheel sticking can be prevented, and the construction quality of the pavement is improved.

The constructor can use one or a plurality of rubber-tyred rollers to compact according to the width of the road surface, and can use one or a plurality of double-steel-tyred rollers to compact.

In addition, the constructor confirms the number of rolling passes in the initial rolling, the secondary rolling and the final rolling according to the test result performed in the test stage.

Specifically, the rolling principle of the rubber-tyred roller and the double-steel-wheeled roller is as follows: rolling from the lower part to the higher part of the ground. The adjacent calender belts should overlap 1/2 wheel widths, pressing a full width.

Preferably, after the final pressure is finished, the construction coring result can be detected. On the basis of the density of the Marshall test piece on the same day, the compactness is controlled to be not less than 98 percent, and the compactness is calculated to be controlled to be 93-97 percent of the maximum theory by taking the maximum rational density as a standard.

Furthermore, an automatic water spraying device is arranged on the double-steel-wheel road roller; the automatic water spraying device is used for spraying water mist to the tire. Therefore, the phenomenon that the asphalt mixture is stuck to the roller in the rolling process of the double-steel-wheel road roller can be avoided.

Wherein, in order to ensure the compactness and the flatness, the initial pressing is carried out at a higher temperature after paving as far as possible under the condition that the asphalt mixture does not generate push, crack and the like.

Further, in the step of repressing, the tire inflation pressure of the rubber-tyred roller is not less than 0.55MPa in a cold state and not less than 0.6MPa after heating.

Preferably, the air pressure is maintained the same for each tire.

Further, in the step of repressing, when a double-steel-wheel road roller is used for repressing the asphalt mixture, the double-steel-wheel road roller is used for vibrating and repressing the asphalt mixture, wherein the vibration frequency is not less than 35-50 Hz, and the amplitude is not less than 0.3-0.8 mm.

Example 2

On the basis of the embodiment, the invention further provides a pavement construction method, which comprises the asphalt mixture compacting process provided by the embodiment 1. In the using process, the rubber-tyred roller can change inflation pressure according to actual requirements so as to change the grounding pressure, namely the pressure of the rubber-tyred roller to the asphalt mixture can be greater than the pressure of the double-steel-wheeled roller to the asphalt mixture. In addition, in the compaction process, the rubber-tyred roller can be used for kneading, namely, the rubber-tyred roller has a kneading effect, so that particles in a compaction layer can be embedded without being damaged, and the rubber-tyred roller is uniform and compact. And secondly, re-pressing the asphalt mixture by using a rubber-wheel road roller or a parallel-bar road roller, finally performing final pressing and surface compacting on the asphalt mixture by using a double-steel-wheel road roller, and repeating the compacting step, so that the compactness and the uniformity of the asphalt mixture are further improved.

According to the method, the combination of the rolling modes adopted by the process can avoid fine cracks in the initial pressing process, can also enable mucilage formed by asphalt, mineral powder, fine aggregates and the like in the mixture to float upwards, enables the upper surface to be more compact, and enables the waterproof performance to be better, so that the pavement construction quality is improved.

FIG. 2 is a block diagram illustrating steps of a method for constructing a pavement according to an embodiment of the present invention; as shown in fig. 2, further, the pavement construction method includes the following steps:

preparing a lower bearing layer and cleaning the lower bearing layer;

uniformly mixing the asphalt mixture according to the mixing test result;

Wherein, constructors should clean the floating mineral aggregate or impurities on the lower bearing layer and wash with water if necessary. And for the parts which are not polluted by impurities such as cement and the like and cannot be washed away, the parts are chiseled manually. If the lower bearing layer is polluted, the next step can be carried out under the condition that the lower bearing layer is blown clean by a blower or is washed clean by a water vehicle and then is dried in the air.

Specifically, the cleaning of the lower bearing layer comprises: (1) rough sweeping: organizing manual work to primarily clean the lower bearing layer which is qualified in acceptance, and removing all loose soil on the surface; (2) fine sweeping: cleaning the lower bearing layer by using a mountain cat sweeper; (3) fine sweeping: manually brushing the parts with serious local pollution by a steel brush or washing by water; cleaning the dead corners of the bridge head and the like manually and intensively, and blowing away floating dust; (4) and (5) closing the traffic of the cleaned lower bearing layer, and forbidding pedestrians and vehicles to pass.

After the lower bearing layer is prepared, the central line recovery is carried out on the adhesive layer which is qualified after the acceptance, the paving thickness of the asphalt middle surface layer is controlled by adopting a non-contact balance beam method, and the loose paving thickness is calculated according to the loose paving coefficient, so that the paving thickness of the middle surface layer can be better ensured, and the good flatness can be obtained.

Wherein, the concept of the asphalt surface layer is as follows: the surface layer of the asphalt pavement has a single-layer structure, a double-layer structure and a three-layer structure according to the requirements of functionality and structure. The single-layer surface layer only has a surface layer; the double-layer structure is divided into a surface layer and a lower bearing layer; the three-layer structure comprises a surface layer, a middle layer and a lower bearing layer. The structure of the surface layer depends on various factors such as the grade of the highway, the traffic volume and the like, and usually, a three-layer asphalt surface layer structure is selected for the expressway and the first-level highway; two-layer asphalt surface course is generally adopted for the level roads below the second level and the third level.

Specifically, after the lower bearing layer is cleaned, the construction of the adhesive layer is carried out. The adhesive layer is sprayed by an asphalt spraying vehicle, and the nozzles and the oil spraying pipes are preheated before spraying, so that each nozzle and each oil spraying pipe are ensured to be free of blockage. The spray angle of the nozzles is adjusted so that the spray fans of each adjacent nozzle have a small amount of overlap at their lower corners. The asphalt is sprayed from the central separating zone to the lanes, and the adjacent spraying zones are controlled to overlap by 10-15cm to avoid leakage. The spreading amount is controlled to be 0.3-0.6L/square meter per square meter. When the spraying is carried out, the kerbs, the kerb belts, the road shoulder prefabricated plates, the longitudinal drainage ditches and the structures nearby the spraying area are covered by plastic cloth, so that pollution is prevented. The spraying needs to be uniform, the oil injection quantity needs to be strictly controlled, the quantity is small and not much, and oil pockets are not allowed to appear. After the adhesive layer emulsified asphalt is sprayed, other vehicles and pedestrians except the asphalt mixture transportation vehicle are strictly prohibited to pass through. The temperature of the sprayed asphalt material is lower than 10 ℃, and the asphalt material is not sprayed when the spraying quality is influenced by strong wind. After the adhesive layer asphalt is spread, it is demulsified, and after the water is evaporated, the asphalt-spreading layer can be spread.

In the step of transporting the asphalt mixture to the road surface to be constructed and paving the asphalt mixture, particularly, a carriage of a dump truck used for transporting the asphalt mixture is cleaned. In order to prevent the asphalt mixture from being bonded with the carriage plate, the carriage side plate and the bottom plate can be coated with a thin layer of oil-water mixed liquid, but residual liquid cannot be accumulated at the bottom of the carriage. When the materials are discharged from the mixing station to the dump truck, the dump truck is moved every time one bucket of materials is discharged, and the materials are charged according to the sequence of front, back and middle, so as to reduce the segregation phenomenon of coarse and fine aggregates. When the dump truck is loaded, the distance between the outlet of the mixture and the carriage is reduced as much as possible, the dump truck is filled three times before, after and during loading, and the dump truck is moved one position for each loading to reduce segregation. When the asphalt mixture is spread, if the asphalt mixture is stuck by an asphalt mixture conveying vehicle or a sticky layer is broken in rainy days, manual filling should be carried out in time.

In addition, the dump truck should be covered with tarpaulin to preserve heat or avoid environmental pollution. The four corners of the lathe groove are sealed and firm. In the continuous paving process, the dump truck stops 10-30cm in front of the paver and cannot impact the paver. When the paver advances to contact with the rear wheels of the dump truck, the unloading can be started, and the mixture cannot leak out between the paver and the dump truck. During the unloading process, the dump truck is in neutral position and is pushed to move forward by the paver.

Preferably, the asphalt mixture is transported to the site at a temperature of no less than 170 ℃.

When the middle surface layer of the asphalt mixture is paved, the loose paving coefficient is 1.2, and the adjustment is carried out at any time in the paving process, so that the final meeting of the design requirement is ensured.

In the process of paving the asphalt mixture, the paving speed is ensured to be uniform, and the shutdown is reduced as much as possible.

When the middle surface layer of the asphalt mixture is paved, two pavers of the same type are adopted to form a ladder-type combined paving, and the distance between the front side and the rear side of each paver is generally 5-10 m. The front and rear paver tracks are overlapped by 10-20 cm, the longitudinal joint position is proper, the front and rear paver tracks cannot be placed at the track position of a travelling wheel, cannot be overlapped with the longitudinal joint position during the construction of the next layer, and are placed at the position of a mark line between a travelling lane and a passing lane or between two mark lines of the travelling lane.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. The asphalt mixture compacting process is characterized by comprising the following steps of:

2. The asphalt compaction process of claim 1 where prior to the step of compacting the paved asphalt with a rubber-tyred roller, further comprising:

and (3) coating the anti-bonding agent on the tire of the rubber-tyred road roller.

3. The asphalt mixture compacting process according to claim 1, wherein in the initial compacting step, a rubber-tyred roller is used for kneading and compacting the asphalt mixture, and the compacting speed is 2.5-3.0 km/h;

in the step of repressing, when a rubber-tyred roller is selected to repress the asphalt mixture, kneading and compacting the asphalt mixture by using the rubber-tyred roller at a rolling speed of 3.5-4.0 km/h;

in the final pressing step, a double-steel-wheel road roller is used for respectively carrying out static pressing on the asphalt mixture until no tire trace exists, and the rolling speed is 3.0-4.0 km/h.

4. The asphalt mixture compacting process according to claim 1, wherein an automatic water spraying device is arranged on the double-steel-wheel road roller;

the automatic water spraying device is used for spraying water mist to the tire.

5. The asphalt mixture compacting process according to claim 1, wherein the temperature of the asphalt mixture at the initial compaction is not less than 150 ℃ and the temperature at the re-compaction is not less than 90 ℃.

6. The asphalt mixture compacting process according to claim 1, wherein in the re-compacting step, the tire inflation pressure of the rubber-tyred roller is not less than 0.55MPa in a cold state and not less than 0.6MPa after heating.

7. The asphalt mixture compacting process according to claim 1, wherein in the step of re-compacting, when a double-steel-wheel roller is used for re-compacting the asphalt mixture, the double-steel-wheel roller is used for vibrating and compacting the asphalt mixture, the vibration frequency is not less than 35-50 Hz, and the vibration amplitude is not less than 0.3-0.8 mm.

8. A method of road surfacing, characterized in that it comprises a process of bituminous mixture compaction according to any one of claims 1 to 7.

9. A pavement construction method according to claim 8, characterized by comprising the steps of:

preparing a lower bearing layer and cleaning the lower bearing layer;

uniformly mixing the asphalt mixture according to the mixing test result;

10. The method for constructing a road surface according to claim 9, wherein in the step of transporting the asphalt mixture to the road surface to be constructed and paving the road surface, the temperature of the asphalt mixture when paving the road is not lower than 160 ℃.