Characteristics of Cyclic Freeze-Thaw of a Highway Pavement and Subgrade

Temperature has a strong influence on the mechanical behavior of road pavement layer materials and subgrade soil which requires reliable information on temperature changes in them. At different characteristic periods of a year temperature can be one of main factors in a destruction of structural elements of highways. This paper analyzes the results of monitoring of temperature and moisture in layers of a pavement structure and its subgrade on the section (58 km + 895 m) of the “Almaty-Bishkek” highway. The monitoring was carried out using a special measuring system. In particular, based on the measured temperature values, characteristics of cyclic freeze-thaw (number, durations and minimum temperatures) in the first asphalt concrete layer of the pavement are established: the number of FTCs is 83; most FTCs have a duration of no more than 20 hours (80.72%) and a minimum temperature of no lower than -6°C (more than 80%); there are correlations between duration and minimum temperature for short (less than 25 hours) and (more than 25 hours) long durations. Correct accounting of the characteristics of FTCs will increase the strength and durability of road pavements.