Friction after polishing – initial experiences of new test method to predict skid resistance of Irish road surface materials

Shaun Friel, David Woodward

Research output: Other contribution


The friction after polishing (FAP) test has recently been included as a requirement in the new NRA Specification for Road Works Series 900 [1]. This paper reports one of the first studies into the use of the FAP test using aggregate and asphalt mixtures commonly used in Ireland. The study was carried out at the French Institute of Science and Technology for Transport, Development and Networks (IFSTTAR) located in Nantes as the FAP test equipment is currently not available in Ireland.This study is important as the specification requirements for aggregate and asphalt road construction surfacing materials are being made CPR compliant. Prior to this study, Ireland had almost no experience with the FAP test. This paper compares the three types of asphalt mix commonly used in Ireland and the UK i.e. Stone Mastic Asphalt of 14mm and 10mm nominal size and Hot Rolled Asphalt with 20mm rolled-in chippings.The data produced during the FAP testing of HRA and SMA mixes produced new insight into skid resistance compared to what the PSV test offers. This new information allows a method to optimise the use of aggregate in different types of asphalt mix and to show their frictional speed dependency. However, visual assessment of the FAP roller / asphalt test specimen interface raises questions relating to what the FAP test is actually measuring.
Original languageEnglish
TypeOnline article in Engineers Journal
PublisherEngineers Ireland
Number of pages8
Publication statusPublished - 23 Feb 2016



  • Friction after polishing
  • FAP
  • skid resistance
  • Ireland

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