|Written by City Engineer|
|Monday, 15 August 2011 21:03|
Question: What is seal coating? Why does the City do this to the streets in the summer?
Answer: Seal coating (also known as chip sealing) is a maintenance procedure that is done to help preserve pavements. As both sealcoat and asphalt pavements age, cracks form in the surface. The cracks allow water to penetrate the road base, weakening the pavement. The oil that is applied to the surface seals these cracks, helping to waterproof and protect the pavement.
Typically, a sealcoat application may be reapplied every three to five years. The condition of the pavement dictates the frequency.
The sealcoating process begins with cleaning the pavement with a street sweeper to remove loose rock and debris. A Distributor is used to apply the bituminous material (oil) at a controlled rate. Following the Distributor is a self-propelled Chip Spreader. This piece of equipment takes rock from dump trucks and applies a uniform layer across the pavement. After this, a Pneumatic (rubber-tire) Roller is driven across the new sealcoat surface to help ‘seat’ the rock. The final step in the process is to remove excess rock with a street sweeper to help prevent accumulations of loose rock on the street.