Explained: What Is Bitumen, the Material Behind Rironi-Mau Road Delays?

Bitumen shortages in Kenya have delayed the opening of the Rironi-Naivasha section of the Rironi-Mau Summit highway, which was scheduled for the end of October 2026. Bitumen is a black, sticky binder that combines aggregates such as crushed stone, gravel and sand to form asphalt road surfaces. Mostly obtained from the heavy residue left after crude oil refining, it hardens as it cools and helps roads withstand traffic and resist water. Kenya once produced bitumen at its Mombasa refinery but has imported all supplies since the refinery stopped processing crude oil in 2013.