Longitudinal Thermal Cracking Phenomenon: Thermal Imaging Detection and Laboratory Case Studies

摘要

Since 2008, most of the contracts for the Ministere des Transports, de la Mobilite Durable et de l'Electrification des Transports (MTMDET) that include bituminous pavement provide technical specifications for a control procedure on site using infrared imaging.For overlays and new construction, specific studies were conducted over the past few years in order to determine what causes longitudinal cracks. Analyses of the thermal images taken during asphalt paving, asphalt core extraction, analyses of asphalt mix characteristics, mechanical testing on samples, and tomodensitometry analyses were performed to provide explanations of the longitudinal thermal cracking phenomenon. The mechanism leading to the development of this cracking is closely linked to the presence of a plane of weakness; a clear rectilinear discontinuity affecting the mechanical properties and durability of pavement.The cases studied indicate that the use of that method in various contexts is an efficient and reliable approach for detecting thermal streaks in the asphalt mat. The results demonstrate an obvious link between the presence of Longitudinal Thermal Segregation (LTS) caused by paving equipment and the development of cracks. Thermal imaging with infrared cameras or an automated thermography system are the most appropriate means of control to determine the quality of asphalt paving.