What construction material is primarily used for paving in oil surfacing?

The primary construction material used for paving in oil surfacing is asphalt. This is because asphalt provides excellent durability and flexibility, making it well-suited for accommodating changes in temperature and traffic loads. It is a byproduct of petroleum, which contributes to its binding properties. The material can also be easily applied, allowing for efficient road construction and maintenance.

Asphalt's ability to create a smooth riding surface while being resistant to water damage adds to its popularity in paving applications. Additionally, the resurfacing of existing roads with asphalt can extend the life of the roadway, making it an economical choice in construction practices.

In contrast, while concrete can also be used for paving, it is not typically associated with oil surfacing techniques. Gravel and clay are less commonly used for paving as they do not provide the same long-lasting and weather-resistant characteristics that asphalt does. These materials are more often used for base layers or in different types of applications altogether.