In the construction of SMA pavement, oil spots may appear during the paving and compaction process. The reasons for the formation of oil spots are as follows:
- Long transportation distance causing segregation between aggregates and asphalt in the SMA mix.
- High temperature of the SMA mix causing asphalt aging.
- Uneven mixing of fiber additive.
- Short mixing time leading to insufficient mixing of the SMA mix.
- Excessive oil usage.
- Excessive number of roller passes causing over-compaction of the pavement.
- Certain moisture content in the mixing material (especially fiber additive) and on the road surface.
- Prolonged time for paving or excessive pressure from delivery trucks leading to asphalt bleeding.
Oil spots that appear during paving should be promptly removed and filled with hot mix. For oil spots during compaction, machine-made sand should be spread in the affected area. Paving work should be strictly prohibited in case of rain or when the lower layer is wet during paving.
