Characteristics of Asphalt Pavement Damage in Degrading Permafrost Regions: Case Study of the Qinghai-Tibet Highway, China

In the context of climate warming, damage to road pavements and embankments in permafrost regions caused by thawing of underlying permafrost severely reduces the serviceability of roads. In this study, 10 types of asphalt pavement damage were measured every kilometer along the Qinghai-Tibet Highway (QTH), from Kunlun Mountain to Tonggula Mountain (approximately 440km in permafrost regions). Based on observed data and embankment geometry along the QTH, and information about the characteristics of the permafrost, aspects of pavement deterioration are analyzed and discussed. The three most common forms of pavement damage in the permafrost regions are transverse cracking (TC), potholes, and longitudinal cracking (LC), observed in 87, 64, and 57% of the study section, respectively. About half of the damaged pavement was also affected by block cracking (BC) and alligator cracking (AC), in addition to LC and TC. Results also showed that pavement damage in the degrading permafrost regions was closely related to the underlying permafrost characteristics and embankment geometry. Damage from settlement and patching were more severe in sections with high ice content than low ice content. All the above forms of damage increase exponentially with higher underlying permafrost temperatures. Because of the significant thermal effects of sunlit/shaded slopes, BC, LC, and TC cracking is closely related to roadway orientation, with the most severe cracking damage observed in roads oriented approximately east to west (E-W). Also, more LC was seen in sections of greater embankment thickness, which exacerbates the sunlit/shaded thermal effect. (c) 2018 American Society of Civil Engineers.