Case studies

M20 Friction & Texture Testing


R3 were commissioned by National Highways and Roadgrip Ltd to undertake friction testing and sand patch testing as part of the trial for longitudinal grooving of concrete roads.

What was the challenge?

National Highways are conducting a trial to try to reduce the noise levels of concrete roads in England using longitudinal grooving. As part of this they want to increase the skid resistance properties and drainage in order to extend the life of the 300 plus km of concrete road surfaces in England. The process involves retexturing the surface rather than using surface dressing or thin surface courses which increases carbon output and uses finite resources.

Roadgrip Ltd are trailing their grooving system. As part of the trial, National Highways requested before and after texture and friction testing. This is difficult because they are working under time constraints in closures on the trunk road network.

What was the solution?

R3 Ltd were commissioned to provide friction testing and volumetric sand patch testing after the grooving retexturing process at various locations on each of the three lanes of the M20. The purpose of the survey was to give an indication of the skid resistance and mean texture depth during the trials to ensure the retexturing process was meeting target.

The micro GripTester was used to measure wet and dry skid resistance. This allowed for the survey to be done in a safe manner in the traffic management enclosure without the need for a vehicle travelling at speed. The micro GripTester data was then compared before and after the retexturing process.

The Volumetric (Sand) Patch Test was completed in accordance with standard EN 13036-1. This is used to determine the mean texture depth of a surface using glass beads. This was done on treated and untreated sections.

The results showed the skid resistance had improved by around 30% and the texture had increased by 0.2mm which was within the requirements for the trial.

The works were required at short notice and R3 managed to mobilise quickly to get the data for the client.