Road oil is an asphalt product used in sealing and protecting roadways. It consists of a very thick fluid applied with a sprayer to the surface of the road. Manufacturers of asphalt products usually carry it and can formulate by request for customers. It can also be purchased in places like hardware and home improvement stores for small projects like sealing asphalt driveways.
Road oil is viscous and very dark. It tends to stain readily, something people must be careful of when working with it, and it can also cause clogs and jams in equipment. When people are paving new roads or making repairs, they often finish with a layer of the oil to protect the surface. The oil will create an insulating layer, as well as permeating into the material, holding the road together and resisting water, sand, and other materials known to damage roadways.
People driving or walking on freshly paved asphalt surfaces often notice a tacky layer of black gunk adhering to their shoes or sticking to the bottom of a car. This is mostly road oil, and as it cools, it will harden and stain. Solvents should be used to remove it. People can usually find asphalt solvent, including solvents designed to remove asphalt products from vehicles without stripping, staining, or otherwise damaging the paint job.
Construction crews working with road oil use sprayers specifically designed for it and typically wear protective gear. This petroleum product can be dangerous for the skin and it is important to minimize direct contact with it. Long sleeves, pants, and gloves are usually worn, and some people may also wear face masks to address concerns about spray being carried back on the wind. Drivers and passersby should be careful around oil sprayers.
It is possible to apply a layer of road oil to reseal a road periodically without having to repave it. This is done to keep the road in good condition and extend the time between paving by keeping the surface as clean and even as possible. Potholes can be filled with a solution of asphalt pavement crushed into the roadway and covered with oil to seal it, although this measure is generally only temporary, as the paving will flake away at the edges of the pothole. Eventually, wear and tear on the road will make it necessary to tear up the asphalt paving and replace it with a fresh layer.