Why do chip seals fail?
Oil and stone, more properly known as a chip seal, fail for a variety of reasons but, more often than not fail when the stone does not properly adhere to the pavement. This stone loss is most commonly a result of a misstep in the initial installation.
Installation factors that can attribute to stone loss include:
- Applying the treatment in the wrong weather
- An improper emulsion application rate
- An improper aggregate application rate
- Placing the aggregate too late and after the emulsion has broken
- Dirty aggregate
Aside from timing and application rates, there are five steps that should be taken during the construction process:
- Sweeping before the emulsion application
- Spraying the emulsion
- Spreading the aggregate
- Rolling the aggregate
- Sweeping the excess stone off of the road surface a day or two after the chip seal is placed.
References
Pavement Cracking: A Failure Indicator of Your Roads
CLRP Quick Answer
Pavement Maintenance
CLRP Workshop Manual
