A road roller, also known as a soil compactor, is a type of road repair equipment, divided into two categories: steel wheel and tire. Rollers belong to the category of road equipment in construction machinery and are widely used for filling and compaction operations in large-scale engineering projects such as high-grade highways, railways, airport runways, dams, and sports stadiums. They can crush sandy, semi cohesive, and cohesive soils, roadbed stabilized soils, and asphalt concrete pavement layers. The roller is suitable for various compaction operations due to the gravity of the machinery itself, causing permanent deformation and compaction of the compacted layer.
The roller structure includes light rollers, groove rollers, and sheep foot rollers. The most common application of smooth rolling is mainly for compacting the pavement surface layer. Using mechanical or hydraulic transmission, it can concentrate strength to compact protruding parts, with high compaction smoothness, suitable for asphalt pavement compaction operations.
Operating procedures
1. When working, the roller should start first before starting the vibration, and the internal combustion engine should be set to medium speed first, and then adjusted to high speed.
2. When shifting or reversing, the engine should be stopped first, and when shifting, the engine speed should be reduced.
3. It is strictly prohibited for the roller to vibrate on solid ground.
4. When rolling soft roadbeds, they should be rolled 1-2 times without vibration before vibration rolling.
5. During compaction, the vibration frequency should be kept consistent. For adjustable vibratory rollers, the vibration frequency should be adjusted before operation, and the vibration frequency should not be adjusted without vibration.
6. The adjustment of the reversing clutch, shock absorber clutch, and brake should be carried out after the main clutch is disengaged.
7. When going up or down hills, do not use the fast gear. It is strictly prohibited to use the fast gear during sharp turns, including when using articulated vibratory rollers to roll around small turns.
8. The roller must not engage vibration while driving at high speeds.
9. When stopping the engine, the vibration should be stopped first, then the reversing mechanism should be placed in the middle position, the transmission should be in neutral, and finally the handbrake control lever should be pulled. The internal combustion engine should idle for a few minutes before turning off.
10. Other homework requirements should comply with the regulations for static pressure rollers.
Whether going uphill or downhill, the bottom layer of asphalt mixture must be clean and dry, and an asphalt binder layer must be sprayed to prevent the mixture from slipping during rolling.
Whether it is uphill rolling or downhill rolling, the driving wheel of the roller should be at the back. This approach has the following advantages: when going uphill, the rear drive wheels can withstand the slope and the driving force provided by the machine itself, while the front wheels initially compact the road surface to withstand the larger shear force generated by the drive wheels; When going downhill, the impact force generated by the self weight of the road roller is offset by the braking of the driving wheels. Only the mixture crushed by the front wheels has the ability to support the shear force generated by the driving wheels.
When rolling uphill, the roller should start, stop, and accelerate smoothly to avoid excessive or insufficient speed.
Before rolling uphill, the mixture should be cooled to the specified lower limit temperature, and then subjected to static preloading. Only when the temperature of the mixture drops to the lower limit (120 ), vibration compaction should be used.
When rolling downhill, sudden speed changes and braking should be avoided.
When rolling downhill on steep slopes, a lightweight roller should be used for pre compaction first, and then a heavy-duty roller or vibratory roller should be used for compaction.
Low temperature impact
Low temperature makes it difficult to start the engine, mainly due to increased viscosity of lubricating oil, decreased working capacity of the battery, and poor fuel atomization.
The viscosity of engine oil increases as the temperature decreases, leading to a decrease in flow performance and deterioration of engine lubrication conditions, resulting in an increase in crankshaft rotational resistance.
When the battery is at low temperature, the viscosity of the electrolyte also increases, the permeability decreases, and the internal resistance increases, resulting in a significant decrease in battery capacity and terminal voltage, and even inability to discharge. The voltage drop prevents the starter from obtaining the required output power, making it difficult to achieve the required starting speed.
Due to the low temperature, the crankshaft speed during engine start-up is not high, the intake pipe temperature and gas flow rate are low, and the quality of fuel atomization is poor, which further increases the difficulty of engine start-up.
Under low temperature conditions, various oils have high viscosity and poor fluidity, which brings difficulties to the operation of the roller and exacerbates the wear of the components.
The viscosity of lubricating oil is high, which increases the loss of stirring power during the operation of the mechanism, resulting in a decrease in engine power and low efficiency of the transmission system, thereby reducing the driving ability of the roller walking and vibration excitation mechanism.
The poor fluidity of lubricating oil increases the difficulty of lubricating certain components, reduces the lubrication effect, and thus exacerbates the wear of engine and transmission components.
The viscosity of the working fluid is high, which also increases the resistance of the pipeline, making it difficult to operate the hydraulic steering. The efficiency of the hydraulic drive brake deteriorates, making it difficult to drive the vehicle and having an adverse effect on safe driving.
There is a common risk of freezing during construction in cold seasons, such as the freezing of the electrolyte in batteries, which can cause them to terminate their operation; The freezing of cooling water in water-cooled engines can cause the radiator and cylinder block to freeze and crack.
