Design of a Device for Measuring the Thermal Conductivity of Granular Materials Using the Thermal Probe Method

In West Africa, the behavior of road base layers made of unbound granular materials in the face of temperature remains uncontrollable to date. To better understand this behavior, it is important to design a data acquisition device that allows the calculation of the thermal conductivity of said layers. This device is based on the thermal probe method governed by the ASTM D5334 standard. The device allows the measurement of temperature as a function of time for a minimum duration of 1000 seconds per test. The calibration of the device is done by measuring the respective conductivities of dry swale sand and charcoal powder, two materials whose thermal conductivities are known and documented. The calibration coefficient obtained is identical for the materials and is 0.97, a specific correction factor to be applied to all thermal conductivity values determined by this device.