Researchers reporting in the American Chemical Society (ACS) Omega have filled microcapsules with a slag-based mixture, designed to be added into asphalt before roads are paved, providing long-term snow melting capabilities in a real-world test.

Researchers have recently incorporated salt-storage systems into “anti-icing asphalt” to remove snow and prevent black ice from forming. However, these asphalt pavements use corrosive chloride-based salts and only release snow-melting substances for a few years.

The aim of this real-life test was to develop a longer-term, chloride-free additive to effectively melt and remove snow cover on winter roads.

Blast furnace slag was used as a key ingredient to create a polymer solution which formed tiny microcapsules that were incorporated into the asphalt mixture.

A real-world pilot test of the anti-icing asphalt on the off-ramp of a highway showed that it melted snow that fell on the road, whereas traditional pavement required additional removal operations. Because the additive used waste products and could release salt for most of a road’s lifetime, the researchers say that is a practical and economic solution for wintertime snow and ice removal.