How to choose the construction conditions of the cold regeneration technology and recycling project

This paper mainly describes how to choose the construction conditions and regeneration scheme by using foam asphalt in situ cold recycling process.

Treatment of deep disease of 1 original pavement

Although foam asphalt cold recycling technology can eliminate many diseases on the original pavement, if the location of the disease is more than the thickness of the regeneration, it is still necessary to deal with the disease.

Therefore, before determining the regeneration scheme, need to do a detailed investigation, understand the original pavement structure form, disease type, disease severity and disease location, also need to analyze the reasons for the occurrence of disease.

Especially for the emergence of slurry, pits, serious cracking sections, require special attention, the conventional method is to deal with. If the regeneration layer of the lower part of the structure of local sections of insufficient strength, but also the need for change fill strong treatment.

2 the impact of climate conditions

Foam asphalt is usually distributed around the aggregate in discontinuous particle state, that is to say, asphalt is "spot welding" and forms net coating on the surface of aggregate. Therefore, the sensitivity of foamed asphalt mixture to temperature is relatively low, which is one of the reasons for the high rutting resistance of foamed asphalt mixture.

However, if the temperature is relatively low, the dispersion of foamed asphalt will be very poor, which directly results in the inhomogeneity of the spot welding coating. In addition, the ambient temperature is too low, milling material and new aggregate temperature will be reduced.

When the foam asphalt contacts with it, the asphalt temperature drops too fast, which will weaken the adhesion ability to the aggregate. The asphalt or asphalt group will directly affect the strength and durability of the mixture.

In general, the ambient temperature above 20 degrees is the ideal temperature for foam asphalt, and the minimum temperature should be above 15 degrees celsius.

The best choice is clear noon construction, sooner or later the low temperature will have a negative impact on the uniform dispersion of foam asphalt.

Practice has proved that if the low temperature construction or after construction rain, take out the integrity of the core sample health time will be relatively long, and even can not get a complete core sample.

3 selection of regeneration thickness

Cold recycled asphalt mixture at 20 DEG C compressive modulus is around 1000MPa. From the point of view of pavement structure design, it is necessary to calculate the equivalent resilient modulus of the original pavement, and then calculate the thickness of a regeneration layer according to the traffic volume and deflection data.

However, the thickness design of foam asphalt mixture also needs to be combined with the actual engineering needs, too thin or too thick will have adverse effects.

When the regeneration thickness is too large, on the one hand, it will bring greater challenges to the compaction machinery; on the other hand, the moisture at the bottom of the recycled layer is difficult to evaporate as soon as possible, which prolongs the curing time and construction cycle.

Regeneration thickness is too small, increase the possibility of a segregation, pavement roughness can not be guaranteed, and the foam asphalt dispersion uniformity will be affected; on the other hand, the foamed asphalt layer to retard the reflection crack effect will be greatly reduced.

Therefore, the optimum thickness of foam asphalt cold recycling should be controlled in 12cm~20cm.

To sum up, in the treatment of deep pavement diseases, the influence of climate, temperature and regeneration thickness on the construction of foam asphalt in situ cold recycling process should be taken into account. Consider comprehensive, to smooth construction.