Adhesive properties of tyre tread smear wear and its link to transfer layer deposition onto road surfaces

Rubber wear is typically categorised into three different processes known as abrasive wear, fatigue wear, and smear wear. The mechanisms of the abrasive and fatigue wear have been extensively studied in the past. There are much fewer reports into the smear wear mechanism. Smear wear has also been identified as ‘sticky debris’ by several authors, but there have been no attempts to quantify and characterise this so called ‘stickiness’. Additionally, the ‘stickiness’ could potentially be linked to the transferring of rubber material to a surface when it is abraded against it. This transferred rubber debris is commonly referred to as a transfer layer. This research therefore aims to initially quantify the adhesion of smear wear debris produced from a variety of tyre tread compounds composed of different polymers and fillers. A new experimental method was used to evaluate adhesion energy. This new technique evaluated the adhesive properties of smear wear generated from different tyre tread compounds during abrasion. These results were linked to independent surface abrasion experiments to provide in-depth understanding of smear wear adhesion and how it influences the amount of transfer layer deposited on the countersurface during abrasion.