Traditional manufacturing of asphalt uses petroleum binders, a byproduct of fuel production. While it is a byproduct, it is based on oil and thus not renewable or circular. A group of researchers has found a way of isolating similar oils in pig manure to use them as a binder in asphalt, and has founded a startup to scale up the process. In laboratory tests, the new asphalt proved as durable as traditional asphalt and cheaper to manufacture.

The manufacturing of asphalt requires a binder that is usually made from petroleum that is a by-product of fuel production. This method is problematic from a circularity perspective because it uses large amounts of virgin materials from a non-renewable resource.

Swine manure is a very common resource, as currently there are around 163 billion litres of swine manure being produced per year in the world. This manure contains crude oils that are very similar to petroleum, and could be used in asphalt to act as a binder. The North Carolina Agriculture and Technical University have developed a way to extract these oils and make a binder from it, which shows initial promise to be as durable as the asphalt used in construction presently. It uses a renewable resource, could help to solve the issue of what to do with the manure, and is cheaper to manufacture than traditional asphalt.