During the construction, the width of 10-2ocm of the paved mixture should be left as the elevation datum of the later part
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During trial mixing, all kinds of mineral aggregate and asphalt used shall be strictly measured
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The transverse joints of two adjacent sheets and the upper and lower layers shall be displaced by more than LM
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Asphalt surface treatment is to use asphalt and fine aggregate to build a thin layer of pavement surface with a thickness of less than 3cm, which is usually constructed by layer laying method
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Before mixing asphalt mixture, samples shall be made according to the determined mix proportion
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The mineral materials shall be evenly distributed to fully cover one layer, with uniform thickness, without overlapping of mineral materials and asphalt exposure
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The contents, requirements and precautions of the joint are as follows: hot joint is used for the longitudinal crossing of echelon operation during paving
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When oil spilling is found, caulking material with the same specification as the last layer of mineral material shall be spread evenly at the oil spilling part; when there is too much floating mineral material, it shall be swept out of the way; when there is other damage phenomenon, it shall be repaired in time
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With the paver moving forward, the spiral paver evenly paves the mixture on the width of the paving belt, and then tamps it, and is leveled by the paving plate
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When the asphalt mixture surface of mixing layer is added on the top of the penetration layer, the total thickness should be 6-10cm, and the thickness of mixing layer should be 2-4cm
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Paving construction technology: base preparation and setting out
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The paving process of asphalt mixture paver is that the mixture is unloaded in the hopper by the dump truck, and the mixture is transmitted to the spiral paver by the conveyor
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In order to control the paving thickness of the mixture, after the base course is prepared, measurement and lofting shall be carried out, that is, sample piles shall be set along the center line of the pavement and one fourth of the width of the pavement to mark the loose paving thickness of the mixture
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Asphalt pavement surface construction by spraying method there are two kinds of asphalt pavement surface construction by spraying method: asphalt surface treatment and asphalt penetration type
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The rolling temperature should meet the requirements of construction temperature
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When the automatic leveling paver is used, the control datum line guiding the running direction and elevation of the paver shall be set out
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All floors of other highways can be slanted
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When there is a lack of materials or too much in some parts, it shall be properly repaired or swept
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The construction technology of three-layer surface treatment is as follows: clean the base course
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The longitudinal joint of the surface layer shall be straight, and located at the line drawing position of the lane, and the transverse joint shall be perpendicular to the road center line
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For expressways and first-class highways, more than two pavers shall be used for joint paving to reduce longitudinal secondary cooling joints
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The lap length of inclined joint is related to the thickness, which should be 0.4-0.8m
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When it is found that there is a blank or missing edge after spraying asphalt, it shall be immediately used for supplementary spraying
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For paving, hot mix asphalt mixture shall be paved mechanically
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According to the number of layers of asphalt and mineral aggregate, it can be divided into single layer, double layer and three layer There are three types
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The initial compaction is carried out at a high temperature after the mixture is paved
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If there is accumulation, it shall be immediately scraped off
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Joint construction, all kinds of construction of asphalt pavement, including longitudinal joints, transverse joints and joints of new and old roads, often due to insufficient compaction, it is easy to produce quality accidents such as steps, cracks and looseness, which affect the smoothness and durability of pavement
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After the initial compaction, the flatness and road arch should be checked and adjusted appropriately if necessary
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The re compaction is to use heavy wheel roller or vibratory roller to roll for 4-6 times after the initial compaction to achieve the required compactness and ensure the quality There is no obvious wheel trace, so re compaction is the main stage to achieve the specified compactness; the final compaction is followed by re compaction, and the final compaction shall be carried out by a 60-80kn double wheel roller at least twice, and the wheel trace generated in the rolling process shall be eliminated to ensure the good flatness of the road surface
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After paving, the operator should shovel away the mixture paved on the front half
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Before paving the other half, the edge of the joint must be cleaned and the adhesive layer asphalt must be brushed
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Flat joints shall be closely bonded, fully compacted and smoothly connected
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The joint shall be cleaned and cut up, the edge shall be coated with adhesive layer of asphalt, which shall be ironed with hot iron after compaction, and then the joint shall be coated with adhesive layer of asphalt and sealed with stone powder to prevent water seepage..
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The speed should not exceed 2km / h at the beginning, and can be increased appropriately later
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After testing the asphalt mixture of samples, the construction mix proportion can be selected
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Most of the roller shall be rolled on the pavement that has been paved first, and only 10-15cm width shall be rolled on the newly paved lane, and then gradually move the cross joint for rolling to eliminate the joint trace
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The asphalt penetration pavement is a porous structure
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The rolling process is divided into three stages: initial compaction, re compaction and final compaction
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When the quality of the lower layer does not meet the requirements, or the prime coat, tack coat asphalt or hot seal coat is not spread as required, the asphalt surface course shall not be paved
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However, the mixture for preheating shall be removed before rolling
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When the asphalt penetration layer is used as the bonding layer, the surface sealing material may not be spread
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In order to prevent the surface water from invading and enhance the water stability of the pavement, the top layer of the surface layer should be spread with sealing material or additional mixing layer
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When hot joint cannot be used in half width construction or longitudinal joint connected with old asphalt pavement, it is better to add baffle or cut with cutter
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The longitudinal distance between two adjacent pavers shall be 10-30m, and the transverse width shall be 5-cm
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Therefore, the rolling thickness of each layer of asphalt mixture should not be greater than 10cm, otherwise, it should be paved and compacted layer by layer
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Sprinkle the second layer of asphalt, spread the second layer of mineral aggregate, roll, sprinkle the third layer of asphalt, spread the third layer of mineral aggregate, roll
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Rolling: after spreading a section of ore, use 60-80kn double wheel roller to roll
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The construction process of asphalt penetration pavement is as follows: cleaning base course → spraying prime coat or tack coat asphalt (the thickness of emulsified asphalt penetration or asphalt penetration is less than 5cm) → spreading mineral aggregate of main layer → rolling compaction → spreading the first asphalt → spreading the first caulking material → rolling compaction → spreading the second asphalt → spreading the second caulking material → rolling compaction → spreading the third asphalt → spreading sealing material → rolling compaction → initial stage Maintenance
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Generally, the oil asphalt should be 130 ℃ ~ 170 ℃, the coal asphalt should be 80 ℃ ~ 120 ℃, and the emulsified asphalt should be distributed at normal temperature
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Initial maintenance: after asphalt surface treatment, initial maintenance shall be carried out
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The longitudinal joint shall be rolled immediately after the paving of the post paving part
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The longitudinal joints of the upper and lower layers should be staggered by more than 15cm
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When paving the joint, some hot mixture can be laid on the compacted part to make it preheat and soften, so as to strengthen the bonding between the new and old mixture
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Before paving asphalt mixture, the quality of the lower layer shall be checked and confirmed
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Single layer type and double layer type are part of the three-layer type
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During the construction, the asphalt distributor should be used to spray asphalt, and the distribution length should be coordinated with the mineral aggregate distribution capacity
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When spraying prime coat (or tack coat) asphalt, the first layer of asphalt shall be evenly distributed
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It is better to use 60-80kn double wheel roller to roll twice at a slow speed and evenly
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Hot mix asphalt pavement construction can be divided into two stages: mixing and transportation of asphalt mixture and on-site paving
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When rolling, it should be rolled from one side of the curb to the middle of the road for 3-4 times
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Spreading the first layer of mineral aggregate: after spreading the main layer of asphalt, the first layer of mineral aggregate shall be spread immediately by mineral aggregate spreader or entering the construction site
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The asphalt penetration pavement is suitable for grade II and below highways, and its thickness should be 4-8cm, but the thickness of emulsified asphalt penetration pavement should not exceed 5cm
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The lap joint shall be cleaned and sprayed with tack coat asphalt, and the inclined joint shall be fully compacted and lapped flat
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Before the surface treatment construction, the base course of the pavement should be cleaned, so that most of the mineral materials in the base course are exposed and kept dry; if the overall strength of the base course is insufficient, it should be reinforced first
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The transverse joints of Expressway and first-class highway, middle layer and lower layer can be mitered, but the upper layer should be made into vertical flat joint, that is flat joint
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When rolling, first drive on the compacted road surface, roll the new layer 10-15cm, then gradually move across the longitudinal joint, and roll the longitudinal joint tightly
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When paving, it should be overlapped 5-10cm above the paved layer
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The asphalt distribution temperature should be determined according to the construction temperature and asphalt grade
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After rolling, the compacted asphalt mixture should meet the requirements of flatness and compactness
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