Effects of Large Freeze-Thaw Cycles on Stiffness and Tensile Strength of Asphalt Concrete

Abstract

This study investigates the stiffness and tensile strength degradation behavior of asphalt concrete (AC) on long-term freeze-thaw (FT) conditioned samples in the laboratory. In the first step, beam samples (363×63×50 mm) are prepared in the laboratory using a kneading compactor and conditioned at different numbers of full-day FT cycles up to 150. The flexural stiffness of control and FT conditioned beam samples are determined using a beam fatigue test apparatus. In the second step, circular (100-mm diameter) samples of 50-mm thickness are prepared using a SuperPave gyratory compactor and conditioned in a FT chamber similar to the beam samples. The indirect tensile strength (ITS) of control and FT conditioned circular samples are determined by indirect tensile strength (IDT) tests at different temperatures. Results show that the flexural stiffness of the FT conditioned samples decreases with FT conditioning, whereas the ITS of AC does not change significantly with FT cycles. It is highly expected that the findings of this study will be useful to understanding the damage behavior of AC in cold regions.