Influence of Thermal Gradiente on Non-Destructive Evaluation of Concrete Pavements

The non-destructive evaluation of a concrete pavement must account for the temperature warping condition of the slab at the test time. In fact the thermal gradients induced in the slab by the daily temperature variations cause the temperature warping of the slab and this affects the value of the maximum deflection and of the shape of the deflection basin that can be measured under the test equipment. A theoretical analysis of the temperature deformation of the slab for different thermal gradients, slab thicknesses and lengths, concrete modulus of elasticity and subp,rade support conditions are performed. The results of this analysis are taken as inputs for the following study of the deflections induced in the pavement by the test device. The results showed that different slab support conditions can occur and this requires the development of different slab deflections basin evaluation methods. A simplified approach to such a problem is proposed based on the thin slab elastic theory and on the Wester~aard analysis