Tarred Macadam

Tarred macadam — crushed stone or aggregate bound with tar rather than bitumen or slag — occupies a narrow classification niche under a single tariff line (2517300000), set apart from both slag macadam (251720) and asphalt-based road materials classified elsewhere. Its primary use is in road surfacing and pavement repair applications where tar-based binders are specified. Canada and the United Kingdom are the recorded US import sources, reflecting the product's stronger commercial presence in markets with older road-construction traditions. Importers should verify binder composition, as bitumen-bound materials may classify differently.