Rolling: first level with grader, then roll with light roller, and then compact after reaching the loose paving elevation through inspection.
6. For pavement construction, calculate the earthwork volume to be excavated according to the design elevation of the longitudinal section, level it after the excavation is in place, and then use a vibratory roller for static pressure and light vibration twice to ensure the compactness of subgrade.
6. 1 Lime-flyash macadam base construction
The road base of this project is 28cm thick lime-fly ash macadam, which is constructed by factory mixing method. Set up two construction teams, each equipped with 1 roller.
6. 1. 1 construction preparation
According to the design, prepare for measurement, put piles on the qualified road grooves, cultivate soil on both sides of the construction section, remove the floating soil and accumulated water on the surface of the operation surface, and sprinkle water on the surface to wet it.
6. 1.2 construction of test section
Before construction, the test section with the length of 100m-200m must be paved. The mixing times, compaction method, mechanical combination, working procedure, loose paving coefficient, rolling times and optimum water content are determined through the test section as the basis for base construction. After passing the inspection, the test section should be regarded as a part of the permanent foundation, otherwise it should be excavated.
6. 1.3 According to the process determined in the test section, the cloth is layered by horizontal distribution method. When distributing cloth, each part should have enough cloth for scraping instead of repairing.
6. 1.4 Rolling: firstly, level it with grader, then roll it with light roller, and then compact it after it reaches the loose paving level through inspection. Rolling follows the principle that from the roadside to the middle of the road, it should be light before heavy, the roller should vibrate strongly before light, the lower part should be dense before the upper part, and the rolling should be carried out at low speed. Avoid displacement, peeling and pressure relief. Scrape the surface of subbase higher than the design elevation, and sweep the scraped lime-fly ash macadam. If the local area is lower than the elevation, it can't be repaired, and it must be removed and repaved.
6. 1.5 joint: the joint of two working sections constructed on the same day is treated by lap joint method, and the joint constructed on the next day is treated by working joint.
6. 1.6 curing: after rolling, it will enter the curing period, and the curing period will be covered with grass curtains or other materials approved by the supervisor to keep the subbase moist and prevent the surface moisture of lime-fly ash macadam from evaporating and cracking. No vehicles are allowed to pass during the maintenance period, and the maintenance period is 7 days. Continue to cover after the curing period, and do not expose to the sun. Take anti-freezing measures in winter.
6.2 Pavement Lower Seal Coat
6.2. 1 construction preparation: 6-8 people shall be used to clean the surface of lime-fly ash macadam base, so as to expose the aggregate particles of lime-fly ash macadam base as much as possible.
6.2.2 Construction of test section: Before the formal construction of the lower seal coat, make a test section with a length of not less than 300m ... to determine the quantity, process, aggregate quantity and process of emulsified asphalt.
Sealing layer construction
6.2.3. 1 Use the asphalt distributor to distribute evenly. At the beginning and end, take necessary measures to avoid excessive spraying, and adopt artificial eradication for local excessive spraying; If the spray leaks, it should be replenished manually. Aggregate distribution is completed before demulsification of emulsified asphalt surface. Manually distribute aggregate evenly.
6.2.3.2 uses 6-8t double steel roller to roll twice, and aggregate shall not be crushed.
After rolling, 6.2.3.3 closed the traffic according to the regulations.
6.3 Construction of Medium and Coarse Grain Surface of Asphalt
6.3. 1 Inspection and cleaning of lower bearing layer
Check the integrity of the lower seal or adhesive layer before construction, and repair the insufficient part according to the construction requirements. Clean the lower bearing layer, remove the pollutants on the surface, and rinse with water if necessary.
6.3.2 Paving test section
Before the construction of each layer of asphalt pavement, a test section should be made, and the length of the straight line section of the main line selected in the test section should be not less than 200m m.
6.3.3 Determine the feeding speed, mixing amount, mixing time and mixing temperature of the mixer through trial mixing, and verify the mix design of asphalt concrete mixture.
6.3.4 Determine the treatment method of construction joints and the loose paving coefficient of each asphalt surface layer through trial paving. Determine the mineral mixture ratio and asphalt-aggregate ratio, paving temperature, paving speed, compaction sequence, rolling temperature, rolling speed and times for formal production.
6.3.5 The pavement of the test section can be used as a part of the permanent pavement after all the indexes meet the specification requirements, otherwise excavation will be carried out.
Mixing of asphalt mixture
Strictly control the heating temperature of asphalt and aggregate and the outlet temperature of asphalt mixture. Aggregate temperature is higher than asphalt temperature 10-20℃. After the finished hot mixture is stored in the silo, its temperature drop shall not exceed 5℃, and the storage time of the material shall not exceed 24 hours. The discharging temperature of asphalt mixture should be controlled within the range of 150℃- 165℃, and the mixture above 170℃ or below 145℃ should be discarded. Assign a special person to visually check the uniformity of the mixture and analyze the abnormal phenomena in time.
6.3.7 Transportation of asphalt mixture: Use digital display plug-in thermocouple thermometer to detect the temperature of asphalt mixture at the exit and on site. Trucks are equipped with tarpaulins to keep warm and avoid rain or environmental pollution. In the process of continuous paving, the truck shall stop in front of the paver 10-30cm, and shall not touch the paver. In the process of unloading, the truck is put in neutral and pushed forward by the paver.
6.3.8 Asphalt mixture paving
6.3.8. 1 Continuous and stable paving is the most important measure to improve pavement smoothness. The paving speed of the paver should be adjusted and selected according to the output of the mixer, the support of the construction machinery, the paving thickness and the paving width, and 2-3m/min is appropriate to achieve slow, uniform and continuous paving.
6.3.8.2 surface adopts mobile automatic leveling datum device to control the paving thickness, and automatic leveling system is installed on both sides of the paver, and two workers are sent to monitor the thickness at any time during the paving process, so as to adjust the paving thickness in time.
6.3.8.3 paving in case of rain, immediately stop construction, and remove the uncompacted mixture. The mixture wet by rain is abandoned and shall not be unloaded into the paver for paving.
6.3.9 Compaction molding of asphalt mixture
6.3.9. 1 Compaction of asphalt mixture is an important link to ensure the quality of asphalt pavement. According to the construction technology determined in the test section, choose a reasonable roller combination mode and rolling steps. In order to ensure the compactness and smoothness, the initial compaction should be carried out at a higher temperature after paving as far as possible, so that the compacted mixture will not move or crack.
6.3.9.2 road roller rolls at a slow and uniform speed, and the suitable rolling speed of the road roller varies with the initial pressure, the second pressure, the final pressure and the type of road roller.
In order to avoid the hug caused by the mixture pushing during the rolling process, 6.3.9.3 drives the wheels towards the paver during the rolling process. The rolling route and direction shall not be changed suddenly. For dead corners, edges, seams, etc. Where it cannot be compacted by a roller, compact it while it is hot with a small vibratory roller or a walking vibratory roller. Roller shall not be folded back on the same cross section.
In 6.3.9.4, road rollers or other vehicles are not allowed to park on the uncooled asphalt concrete layer that was rolled that day, and to prevent minerals, oils and sundries from scattering on the asphalt layer.
6.3.9.5's initial pressure, re-pressure and final pressure paragraphs are clearly marked, which is easy for drivers to identify. Set up a special post to check loose laying thickness, rolling sequence, rolling times, rolling speed and rolling temperature.
6.3.9.6 can allow construction vehicles to pass after 24 hours of compaction.
6.3. Treatment of10 construction joint
6.3. 10. 1 longitudinal construction joint: two pavers are used to jointly pave the longitudinal joint in echelon mode, and the paving mixture at the front is left with a width of 10-20cm, which will not be rolled for the time being. As the elevation benchmark at the back, the paving layers overlap about 5- 10cm and are rolled at the end in the form of hot joints. The upper and lower longitudinal seams are staggered 15cm or more.
6.3. 10.2 transverse construction joints: flat joints are adopted. Use a 3-meter ruler along the longitudinal position, and the ruler at the paving end is cantilever-shaped. Determine the joint position where the paving layer is not in contact with the ruler, and remove it after cutting with a sawing machine. When paving continues, the mortar left during sawing should be scrubbed clean and coated with a small amount of viscous asphalt, and the screed of paver should be paved after the seam; When rolling, double steel roller is used for transverse rolling, and the joints gradually move from the first paved pavement to the new pavement layer.
6.3. 1 1 Problems needing attention in the construction process
6.3. 1 1. 1 The ground where various mineral materials are stacked must be hardened and have a good drainage system to avoid material pollution; Different materials should be separated by walls to avoid mixing.
6.3. 1 1.2 Fine aggregate and mineral powder must be covered. Wet fine aggregate will affect the feed rate and mixer output.
6.3. 1 1.3 Each mixer shall design the production mix ratio to ensure the stability of the mixture.
7 masonry engineering
7. 1 Brick watering
Clay brick must be watered and moistened the day before masonry, generally subject to water invading all sides of the brick, with water content of 1.5cm and 10- 15%. Dry bricks shall not be used for normal temperature construction, and bricks with saturated water content shall not be used for building walls in rainy season.
7.2 mortar mixing
Mortar mixture ratio should be weight ratio, the measurement accuracy grade should be recorded as 2%, and sand and gypsum should be controlled within 5%. Mechanical stirring should be used for a moderate time.
7.3 masonry
7.3. 1 Before the foundation wall is laid, the surface of foundation cushion should be cleaned and watered. Then set corners, and the height of each corner should not exceed five layers of bricks.
7.3.2 When the foundation is laid on a wall with a large angle, it is necessary to stay and check the axis and sideline to ensure the correct position of the foundation wall, so that the number of layers at the corner is consistent with the number of poles.
7.3.3 The building height at the corner of the foundation wall shall not exceed five skin bricks at a time, and it shall be hung straight with the board to ensure that the wall is horizontal and vertical. The wall should be hung with 24 backhand lines and more than 37 double lines.
7.3.4 When the elevation of foundation cushion changes or there is a local deepening part, it should be laid upward from a lower place, and the line should be checked frequently to keep the laying straight and prevent the spiral wall from being built.
7.3.5 Masonry is staggered up and down, and there are no 4 skin bricks in each place.
7.3.6 The mortar joint of brick masonry is dense, and the joint is straight with the brick. The thickness of horizontal mortar joint at each joint is not less than 5mm or there are no more than 5 open defects.
8 coating surface engineering
8. 1 External wall base treatment:
1: 3 cement mortar (or polymer cement mortar) shall be repaired and leveled (including frame joints), and then impurities such as ash and pimples on the surface of the base course shall be removed with a shovel and chisel. Brush the loose surface with a wire brush. If the surface is stained with oil, wipe it clean with gasoline. Then use putty to repair the uneven surface defects. After drying, smooth it with 1 coarse sandpaper.
8.2 Polish once with putty: all small sand holes and contraction joints shall be leveled, so as to be compact, smooth and tidy. At the same time, scrape horizontally along the wall, as thin as possible, without leakage or seam rubbing, and be careful not to dirty the surfaces such as doors and windows. After the putty is dry, wrap the flat small board with 1 sandpaper, and polish the putty residue and uneven place, paying attention to the uniform force and protecting the edges and corners.
8.3 Full scraping and second polishing: The second scraping and polishing method is the same as the first one, but this putty is perpendicular to the scraping directions of the previous putty and the previous putty, that is, it should be scraped vertically along the wall surface until the wall surface is further scraped, smooth and smooth.
8.4 First brushing: Before the first brushing, the surface of the base must be cleaned and the floating powder must be wiped off. When brushing your teeth, use a combination brush. The painting sequence is generally from top to bottom, from left to right, first horizontal and then vertical, first edge and then corner, first facet and then paving. Work from top to bottom at the same time and cooperate with each other to avoid overlapping brushing.
The above are collected and sorted by Zhong Da Consulting Company.
For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd