How long should you wait to roll asphalt?
Depending on the temperature, the general paver can start rolling after advancing 20-30 meters. The main consideration is that the road roller has a certain working space. The time from mixing to rolling the asphalt mixture should be controlled within 120 minutes, and the specific time should be determined according to the test.
The general asphalt concrete ground compaction is divided into three stages
1. Initial pressure: Asphalt concrete should be compacted at high temperatures immediately after paving, usually with a light steel cylinder roller and a roller with vibration off. When rolling, the driving wheel should face the paver, and during the rolling process, the route and direction cannot be changed suddenly at will, otherwise, it will deepen the deformity of the road surface.
2. Recompression: After the initial pressure, the recompression needs to be recompressed with vibrating rollers and tire rollers. First, use a vibratory roller to roll about 4 times, and then use a tire roller to roll about 5 times.
3. Final pressure: Asphalt concrete is basically stable after recompression, but the final rolling is still needed. The tire roller is also used for rolling to eliminate the wheel tracks left before, which is also the last of the asphalt concrete pavement Polish in one go. But remember not to stop, turn and brake in the process.
In addition, wait at least 2 hours after finishing the slurry seal before laying asphalt, which can ensure the effectiveness of the slurry seal. If the slurry seal is finished and hot asphalt is paved at any time, the paver and the truck will Damage the slurry seal. It is best to wait 48 hours if construction conditions permit.
What temp do you roll asphalt?
Asphalt pavement paving compaction is divided into three stages: initial pressure, re-pressure, and final pressure (including forming). During normal construction, the rolling temperature is 110-140°C, and not lower than 110°C; for low-temperature construction, the rolling temperature is 120-150°C. The temperature at the end of rolling should not be lower than 65-80°C. The rolling speed should be slow and even.
Can asphalt be compacted at any given temperature?
No, asphalt pavement shall not be constructed under conditions of temperature 10°C (expressways and first-class roads), rainy days, and wet roads. And need to follow the rolling temperature requirements mentioned above.
Due to the special temperature sensitivity of asphalt materials, temperature plays an important role in the performance of asphalt and asphalt mixture. Long-term practical experience shows that the early damage of many pavements is related to temperature. After research, it is found that in the same ingredients, due to the different local temperatures, the performance similar to gradation segregation will occur on the pavement.
In layman’s terms, when the temperature is low, the degree of compaction cannot be achieved, and the gaps in the road surface are large, rainwater is easy to seep into the road surface, and the road surface will soon be damaged. Similarly, when construction is carried out on rainy days or when the road surface is wet, the adhesion between the asphalt and the underlying base layer is not good, and it is easy to be damaged.
How thick should asphalt be after compaction?
Generally, the thickness of the asphalt surface layer on expressways is not less than 15cm, and currently, it is about 20cm.
Generally, roads can be made of two or three layers, and the thickness is thinner than that of expressways. Usually, municipal roads are made of two layers of asphalt (one layer of 4cm, the other layer of 6cm), a total of 10cm.
For newly built or reconstructed (pavement) rural roads, semi-rigid materials such as cement-stabilized gravel and fly ash gravel should be used for the base of the pavement, and the thickness should not be less than 16cm.
What happens if asphalt is too thick?
The ultra-thick asphalt pavement should have little effect on the pavement performance of the asphalt pavement, but it should be considered how to compact the asphalt mixture with such thickness during construction. Because if the construction status is not good, the upper half of the compacted layer will be over-pressurized, while the compactness of the lower half cannot meet the requirements, and the compaction process must be adjusted to meet the requirements.
In addition, if the asphalt layer is too thick, black asphalt has a strong heat absorption capacity. In summer, the temperature of the asphalt road surface will be more than ten degrees higher than the air temperature, and the road surface will become soft. Therefore, when paving the road, a layer of stones should be sprinkled every time the asphalt is poured, and then a road roller should be used to make them stick together.
How many passes are required for asphalt compaction?
The number of rolling passes of the compacted asphalt mixture pavement is about 8-12 passes. Rolling it back and forth counts as one time. The materials are different, the model of the roller is different, the construction technology is different, and the number of times of compaction is different.
What is the minimum degree of compaction of asphalt pavement?
The compactness of the asphalt mixture surface layer should not be less than 96% for urban expressways and main roads; it should not be less than 95% for secondary trunk roads and roads below.
What size roller do you need for asphalt?
In the middle of the compaction, a large road roller is used. According to the actual needs of the road, it may be used from 3 tons to 22 tons.
Small vibratory rollers are used for the corners.
Be careful not to use a large road roller when compacting the edges to avoid structural damage.