Theoretical modeling on the temperature-dependent dielectric properties of concrete pavement materials

The variations of concrete pavement temperature will affect the dielectric properties of concrete, which have a substantial influence on the wireless power transfer efficiency of concrete electrified road and non-destructive accuracy of ground-penetrating radar (GPR). In order to elucidate and describe the variations in the dielectric properties of concrete with temperature, the dielectric properties of aggregates (limestone), six types of cement mortar (matrix) and concrete (two types of Portland Cement: P.O 32.5 and P.O 42.5; three W/C ratios: 0.4, 0.5 and 0.6) within the temperature of-30 degrees C to 60 degrees C were acquired via a network analyzer platform and an open-ended coaxial probe kit. The results show that the dielectric constants of limestone, cement mortar and concrete increase with varying degrees when temperature rises. Furthermore, strong linear agreement between the dielectric constants of limestone, cement mortar and concrete and temperature is identified, indicating that the variations in the dielectric properties of concrete with temperature should be taken into consideration. Mean-while, a temperature-dependent dielectric model of concrete is established by introducing the dielectric-temperature coefficients so as to quantify the influence of temperature on the dielectric properties of con-crete. Compared with the traditional models (Brown model, CRIM model, Looyenga model, and Rayleigh model), the proposed model has the highest precision and is less sensitive to temperature variations. Therefore, the proposed model is more suitable for predicting the dielectric properties of concrete at different temperatures, which is essential for the development of future electrified road and promoting non-destructive accuracy of GPR equipment.