Roadstone Duraflow Porous Asphalt has been designed for use as a surfacing solution for porous pavements and Sustainable Urban Drainage Systems (SUDS) applications. Duraflow has been designed to soak away surface water which then percolates into a stone sub base layer – Roadstone Permeabase. Duraflow surface course incorporates Polymer Modified Bitumen (PMB) and carefully selected high quality aggregates to maximize performance and durability.