The width of the cold regeneration machine for crushing and mixing is 2.4 meters. During operation, a water tank truck should closely follow the operation to ensure the mixing water. During the mixing process, the water should be controlled according to the 1-2% higher than the optimal water content specified in the test sheet (provided that the regeneration machine needs to open several water nozzles to convert the water content). Another water tank truck needs to be full of water and always on standby. Once the water tank working with the regeneration machine runs out of water, it needs to be immediately replenished. To ensure the continuous operation ability of cold revitalization. The travel speed of the cold recycling machine should be adjusted based on the damage condition of the road surface and the depth of regeneration, generally ranging from 6m/min to 12m/min, so that the fluctuation range of the material grading after milling is not large. In areas with severe mesh cracks, the travel speed of the regeneration unit should be reduced and the speed of the milling rotor should be increased. If the thickness of the structural layer of the old road surface is greater than 8cm and it is difficult for the cold recycling machine to move, it is necessary to first mill and plane the old road surface layer with the cold recycling machine, and then lay cement on the crushed material for cold recycling mixing construction. During the cold regeneration process, personnel are required to follow and check the mixing depth and humidity at any time, usually around 20 meters. If there are any nonconformities, they should be reported to the driver in a timely manner for resolution. During each cold recycling construction operation, the vibrating roller must follow the cold recycling machine at a distance of 20m behind it. The mixed mixture should be promptly compacted with high amplitude and low frequency vibration, with a speed equivalent to the driving speed of the cold recycling machine. The purpose is to seal the water in the mixture when the water content is optimal.
Two types of joints should be considered during regeneration construction: longitudinal joints parallel to the road centerline and transverse joints perpendicular to the road centerline.
Longitudinal joint: The working width of the recycling machine is generally smaller than the width of the road or carriageway, therefore, the cold recycling of the full width road requires multiple operations, resulting in longitudinal joints between adjacent working surfaces. It is necessary to have a certain amount of overlap along the entire longitudinal seam to ensure the continuity of the longitudinal seam between adjacent working surfaces. The overlap between adjacent work surfaces shall not be less than 10cm. The thicker the road surface, the greater the overlap; The coarser the material particle size, the greater the overlap; When the interval between two adjacent assignments is more than 12 hours, the overlap should be increased. On the longitudinal joint, change the amount of water sprayed according to the completion time of the existing regeneration layer. The position of the longitudinal joint should avoid the wheel tracks of slow moving heavy vehicles as much as possible. During construction, guidance prompts should be established by prominently marking or measuring reference lines on the existing road surface to help drivers operate the recycling machine correctly and avoid unmixed entrainment between adjacent working surfaces.
Transverse joint: The transverse joint formed by the start or end of each construction is discontinuous. Each shutdown, even if it only takes a few minutes to replace the tanker and blade, will form a serious transverse seam that affects the uniformity of the recycled material. Therefore, during construction, the phenomenon of downtime should be minimized as much as possible. In unavoidable cases, the horizontal joints formed should be carefully overlapped and treated. When handling transverse joints, it is necessary to pay attention to the water content. Generally, the water content should be reduced by half when starting and falling the knife. At the beginning of regeneration construction, all starting steps must be strictly followed in sequence, especially the exhaust procedure of the water pipe. All gases must be expelled before the water reaches the spray bar. If the exhaust is not done properly, there may be no water in the mixture within the first few meters of regeneration construction, leading to unstable road sections on the road surface. When restarting after a temporary shutdown, the entire regeneration unit should retreat at least one rotor diameter distance of 1.5-2 meters to reach the regenerated material. This will ensure that all materials are processed after the start of construction. If the shutdown exceeds the initial setting time of the cement, and the regeneration machine is being constructed again, the entire regeneration machine must be retreated to a distance of 1.5m from the regenerated road section and the cement must be re spread. The problem of transverse joints only occurs when construction stops. Therefore, the regeneration unit can only be stopped after the tank truck is empty or in similar situations. During construction, minimize downtime as much as possible, and preferably replace the cutting head after completing each section of the entire road to avoid affecting the subsequent process.
After the regeneration and mixing are uniform, the color should be consistent, without gray bars, clusters, or flower surfaces, that is, there should be no obvious segregation of coarse and fine materials, and the moisture should be appropriate and uniform. At the end of cold recycling construction every day, the cleaning of the blade must be carried out far away from the road surface of the construction section on that day to prevent the water flow of the blade from entering the newly completed road structure and creating a soft foundation.
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