Special construction scheme for asphalt road paving, rolling and maintenance Project overview This project is asphalt concrete road reconstruction/new construction project. The pavement structure adopts conventional double-layer asphalt structure. The upper layer is 4cm fine-grained SBS modified asphalt concrete (AC-13), the lower layer is 6cm medium-grained asphalt concrete (AC-20), and the base layer is water-stabilized macadam base.The core construction content of the project includes a complete set of procedures such as asphalt mixture transportation, paving, layered rolling, joint treatment, later closed maintenance and quality inspection.
This scheme strictly complies with the Code for Construction and Quality Acceptance of Urban Road Engineering (CJJ1 -2008) and Technical Code for Highway Asphalt Pavement Construction (JTG F40-2004), defines the construction technology, temperature control, compaction standard and maintenance requirements of each process, ensures that the flatness, compactness and compactness of the pavement meet the standards, eliminates cracking, segregation, displacement, seepage and other quality diseases, and ensures the traffic quality and service life of the road.

construction preparation

technical preparation

Organize construction, technical and quality inspection personnel to carry out drawing review and design disclosure, and define core technical parameters such as pavement thickness, longitudinal slope, transverse slope, joint treatment and compaction.Prepare special construction technical disclosure documents in advance, conduct pre-job training for all operators, and refine paving, rolling and maintenance operation points and quality standards.Before formal construction, select representative sections to carry out test section construction, determine the optimal loose paving coefficient, paving speed, rolling combination mode and construction temperature, as the basis for construction of the whole line.

site preparation

Conduct comprehensive inspection and acceptance on the water-stabilized base to ensure that the compactness, flatness and strength of the base are up to standard, and the surface is free from loose, floating dust, oil stain, ponding and other diseases.Thoroughly clean the impurities on the surface of the base course, use a high-pressure blower to clean the dust in the gaps, spray the sticky layer oil evenly on the dry base course, strictly control the spraying amount of the sticky layer oil within 0.3~0.5kg/㎡, spray evenly, without accumulation and leakage, and carry out asphalt paving after the sticky layer oil is demulsified.At the same time, the construction site enclosure, traffic diversion and drainage facilities shall be arranged, and obstacles within the construction scope shall be cleared.

Equipment and Material Preparation

Construction equipment: Equipped with 1 fully automatic asphalt paver, 2 twin steel wheel vibratory road rollers, 1 rubber wheel road roller, sprinklers, mixture transport vehicles, thermometers, flatness meters, compaction detectors and other equipment, complete all equipment maintenance and debugging before construction to ensure stable performance and good working conditions.
Material requirements: asphalt mixture shall be mixed centrally by regular mixing plant, gradation of fine and medium particle mixture shall meet design requirements, all indexes of SBS modified asphalt shall meet standards, aggregate shall be clean without impurities, mud content and crushing value shall meet specification standards.The mixture delivery temperature and transportation temperature shall be strictly controlled. It is strictly prohibited to use the mixture with moisture, segregation and substandard temperature.

Construction environment requirements

It is forbidden to construct in rainy days, foggy days and icy road conditions; asphalt paving is prohibited when the ambient temperature is lower than 10℃.During the construction period, the road surface shall be kept dry without ponding, the construction procedures shall be adjusted in time in strong wind and low temperature weather, and the mixture insulation measures shall be taken to ensure the stable construction quality.

Asphalt mixture paving construction technology

mixture transportation

The mixture shall be transported by closed transport vehicle, the inner side of the carriage shall be coated with anti-adhesive isolation agent, and the whole transportation shall be covered with thermal insulation tarpaulin to reduce temperature loss. The temperature drop of the mixture during transportation shall not exceed 10℃.The transport vehicle shall reverse slowly to connect with the paver, and it is forbidden to hit the paver. When unloading, unload slowly at a constant speed to prevent mixture segregation.Special personnel are required to measure the temperature of the mixture on site. The temperature of the modified asphalt mixture on site shall not be lower than 150℃, and the ordinary asphalt mixture shall not be lower than 135℃. If the temperature does not meet the standards, it shall be removed from the site for disposal.

paving parameter control

Full-width continuous paving with pavers is adopted. When the road width exceeds 6m, two-machine echelon paving is adopted. The spacing between the two pavers is controlled at 5~10m, and the lap width of the two pavers is 5~10cm to ensure that the joints are dense and smooth.The paving speed shall be kept constant and slow, controlled at 2~4m/min, and the whole process shall not be stopped, accelerated or stuck, so as to avoid the problems of paving joints and uneven thickness.
Strictly control the loose paving thickness, determine the loose paving coefficient of 1.15~1.35 in combination with the test section, accurately adjust the paving thickness according to the thickness of the surface layer, assign special personnel to track and detect the paving thickness, cross slope and flatness in the whole process, and timely adjust and correct.During paving process, timely handle partial segregation and material shortage parts, adopt manual fine material leveling, and prohibit large-area manual material supplementation and leveling.

paving temperature standard

The paving temperature of modified asphalt mixture shall be ≥150℃, and that of ordinary asphalt mixture shall be ≥135℃; rolling shall be followed up in time after paving to prevent the natural cooling of mixture from affecting compaction effect.

Asphalt mixture paving construction technology

mixture transportation

The mixture shall be transported by closed transport vehicle, the inner side of the carriage shall be coated with anti-adhesive isolation agent, and the whole transportation shall be covered with thermal insulation tarpaulin to reduce temperature loss. The temperature drop of the mixture during transportation shall not exceed 10℃.The transport vehicle shall reverse slowly to connect with the paver, and it is forbidden to hit the paver. When unloading, unload slowly at a constant speed to prevent mixture segregation.Special personnel are required to measure the temperature of the mixture on site. The temperature of the modified asphalt mixture on site shall not be lower than 150℃, and the ordinary asphalt mixture shall not be lower than 135℃. If the temperature does not meet the standards, it shall be removed from the site for disposal.

paving parameter control

Full-width continuous paving with pavers is adopted. When the road width exceeds 6m, two-machine echelon paving is adopted. The spacing between the two pavers is controlled at 5~10m, and the lap width of the two pavers is 5~10cm to ensure that the joints are dense and smooth.The paving speed shall be kept constant and slow, controlled at 2~4m/min, and the whole process shall not be stopped, accelerated or stuck, so as to avoid the problems of paving joints and uneven thickness.
Strictly control the loose paving thickness, determine the loose paving coefficient of 1.15~1.35 in combination with the test section, accurately adjust the paving thickness according to the thickness of the surface layer, assign special personnel to track and detect the paving thickness, cross slope and flatness in the whole process, and timely adjust and correct.During paving process, timely handle partial segregation and material shortage parts, adopt manual fine material leveling, and prohibit large-area manual material supplementation and leveling.

paving temperature standard

The paving temperature of modified asphalt mixture shall be ≥150℃, and that of ordinary asphalt mixture shall be ≥135℃; rolling shall be followed up in time after paving to prevent the natural cooling of mixture from affecting compaction effect.
Asphalt pavement maintenance scheme
Initial closed curing (core phase)
After the asphalt pavement is rolled and formed, it will be cooled naturally. All vehicles and pedestrians are prohibited from passing through the whole process. It is strictly prohibited to trample, roll and pollute the pavement.Before the road surface is completely cooled to normal temperature, fence and warning signs shall be set up, and special personnel shall be arranged for on-duty control to prevent man-made and vehicle damage.The closed maintenance time shall be no less than 24 hours under normal environment, and shall be extended to 48 hours in low temperature and humid weather.
Regular moisture conservation
After the pavement is cooled and formed, geotextile can be laid for moisture protection to keep the geotextile slightly moist, so as to avoid water loss and cracking of the pavement surface caused by strong light exposure and high temperature drying.The maintenance period shall not be less than 7 days. Heavy vehicles are prohibited to pass during the maintenance period. The traffic speed of light vehicles shall be controlled within 20km/h. It is strictly prohibited to brake suddenly and turn sharply.
late finished product protection
During the maintenance period, it is forbidden to pile up building materials and sundries on the road surface, prohibit cutting, drilling and rolling operations, and prevent oil pollution and mud pollution on the road surface.In case of local minor defects, report to the supervision unit in time for unified repair and treatment. It is strictly prohibited to repair without permission.After the maintenance period expires and all test indicators are qualified, the whole line of traffic can be opened.
Quality control standards and testing requirements

Core Quality Indicators

1, compaction: ≥98%, every 200m test 1 group, pass rate 100%;
2. Smoothness: the deviation of pavement flatness is ≤3mm, and the flatness meter is used for full detection;
3, thickness: surface thickness deviation ±5mm, in line with the design requirements;
4. Horizontal slope and longitudinal slope: deviation conforms to specifications, drainage is smooth without ponding;
5. Appearance: The road surface is dense and flat, the color is uniform, there are no cracks, segregation, pits, wheel tracks, peeling and other diseases, and the joints are smooth without obvious traces.

Process Quality Control

Quality inspection personnel shall be arranged to supervise the whole process, monitor the mixture temperature, paving thickness, compaction times and compaction degree in real time, and make construction account records.After completion of each procedure, self-inspection shall be qualified and submitted to the supervisor for acceptance. After acceptance, the next procedure shall be entered.For problems such as segregation, insufficient thickness and substandard compaction during construction, stop work immediately for rectification to eliminate potential quality hazards.

safe and civilized construction measures

safety construction

Standardized enclosures, warning lights and warning signs shall be set up on the construction site, and sufficient lighting shall be provided for construction at night.Operators shall wear safety helmets, protective clothing, protective shoes and other labor protection articles during the whole process, and it is strictly prohibited to operate mechanical equipment in violation of regulations.Safety warning zones shall be set up during operation of road rollers, pavers and other equipment, and special personnel shall be assigned to direct traffic to prevent mechanical injury accidents.Take measures for heatstroke prevention and cooling in high temperature construction, and take measures for scald prevention and smoke prevention in asphalt mixing and paving operations.

civilized construction

The mixture transportation vehicle shall be covered tightly, and the impurities on the vehicle body shall be cleaned before leaving the vehicle, so as to prevent dust emission and road pollution.Construction waste and garbage shall be collected and cleared in a centralized way to keep the construction site clean and orderly.Reasonably arrange construction time, reduce construction noise disturbance, implement dust control and environmental protection construction requirements.
Prevention and treatment of common diseases

Prevention of pavement segregation

Strictly control the mixing, transfer, transportation and on-site unloading of asphalt mixture during the whole construction process, so as to eliminate problems such as layering segregation and unloading accumulation segregation during transportation.During paving operation, special personnel shall be arranged to inspect the slab surface, and the segregation parts such as local coarse and fine aggregate separation, material shortage and white shall be timely leveled and combed by manual fine materials to ensure uniform distribution of formed pavement aggregate and consistent overall color and compactness.

Prevention and treatment of pavement cracking

Strictly control the construction temperature of asphalt mixture in the whole process of appearance, paving and rolling, and resolutely put an end to low-temperature paving and rolling construction.Standardize the cutting and bonding process of longitudinal and transverse construction joints to ensure that the joints are connected tightly and smoothly.Strictly implement the closed maintenance system, prohibit vehicles and pedestrians from passing ahead of time during the maintenance period, and effectively avoid pavement crack diseases caused by factors such as temperature stress, driving load and base deformation.

Prevention of insufficient compaction

Construction shall be carried out in strict accordance with the established combined compaction process of initial compaction, recompaction and final compaction. It is strictly prohibited to reduce the number of compaction times or change the compaction sequence at will.Track and monitor the rolling construction temperature in the whole process to ensure that the rolling temperature at each stage is controlled within the allowable range of the specification, and prevent the compaction degree caused by low temperature rolling from failing to meet the standard.Focus on strengthening the compaction control of weak areas such as pavement edge, inspection well periphery and construction joint, eliminate pressure leakage and underpressure blind area, and ensure that the overall compaction degree is uniform and up to standard.

Prevention and control of road ponding

Before construction, accurately check the longitudinal slope and transverse slope parameters of the designed pavement. During the whole process of paving and rolling, use instruments to check the slope and flatness of the pavement in real time, and timely adjust and correct the local height difference.Strictly control the uniformity of paving thickness, ensure the overall smoothness and straight slope of the pavement during the rolling process, eliminate local low-lying areas, and ensure smooth drainage after the pavement is formed, without hidden dangers of ponding and stagnant water.

Prevention of joint dislocation

Strictly standardize the cutting process of new and old pavement joints, ensure that the joint section is smooth, vertical and burr-free, and thoroughly clean up dust and sundries at joints.Apply tack coat oil evenly before joint construction to ensure tight adhesion between the old and new asphalt layers.After paving is completed, priority shall be given to cross-joint rolling at joint positions to eliminate joint height difference, so as to ensure smooth and dense construction joints without misplacement, cracking and water seepage defects.

construction acceptance

After the completion of the whole process construction and the expiration of the maintenance period, the construction data, inspection accounts, test reports and other data shall be sorted out, and the completion acceptance shall be carried out jointly with the construction unit and supervision unit.Focus on checking such indicators as road compaction, flatness, thickness, appearance quality, joint quality, drainage effect, etc., and officially open traffic after acceptance.