Long-term monitoring of the white-topping slab and thermo-mechanical analysis

White-topping is pavement rehabilitation technique that uses a thin cement concrete overlay. This article summarises the results of continuous five-year monitoring of a single white-topping slab of size 1.75×2.0×0.14 m over a deteriorated asphalt concrete pavement. The monitored data show asymmetric thermal gradients, curling and warping effects, slab curvatures and continuous progressive separation of the slab from the asphalt concrete, reaching a gap of about 0.3 mm. A thermo-mechanical model with elastic behaviour, bilinear contact elements and a Winkler–Pasternak subsoil plate was assembled to replicate the effects of characteristic summer cycles and traffic loading on the slab. The single-slab and multi-slab model approaches were compared. Based on known subsoil characteristics, parameter ranges for the Winkler–Pasternak model were calculated. The model validation shows good agreement with the measured temperature and strain evolution during a characteristic summer temperature cycle. The highest principal stresses always occur on the bottom surface: 2.97 MPa for combined temperature and traffic loading, 1.66 MPa for traffic loading and 1.37 MPa for temperature loading. The sensitivity of the predicted stress to the asphalt stiffness was quantified over two orders of magnitude of the asphalt modulus. The combination of long-term monitoring data and thermo-mechanical modelling demonstrates an integrated approach to evaluate white-topping performance.