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To enable the improvement of the modelling of pavement response and performance, the measurement of full-scale tyre surface contact stress distributions in all three of the coordinate directions was undertaken. An apparatus comprising strain-gauged pins housed in a strong steel box, mounted flush with the pavement surface was built. The pins were designed to sense the contact forces imposed on them by the tyres.

A programme of full-scale load testing was carried out (single and dual tyres, wheel loads of 40 and 50kN, and inflation pressures of 280, 550 and 690kPa).

Typical results for the vertical pin loads agreed with patterns seen in the literature. However, this was not the case for the longitudinal and transverse pin loads.

Comparisons were made between pavement response predicted by a finite element model for two loading cases:

1. a uniformly distributed pressure on the tyre contact patch, and
2. the non-uniform contact stresses derived from the experimental results.

Differences in pavement response were generally measurable but not great. The difference in pavement performance was significant.

The report includes a comprehensive literature search. All measured experimental results have been posted to a publicly available website.

Keywords: CAPTIF, contact stresses, full-scale testing, numerical modelling, pavement performance, pavement response, rutting, thin pavements, tyre contact patch, tyre scuffing