Case Study on Performance of Pavement Constructed with Modified Binder Meeting Extended BBR and DENT Specifications

摘要

Understanding and preventing cracking in flexible asphalt pavements is challenging due the complexity of individual mechanisms and their interaction. Battersea Road in Kingston, Ontario was pulverized and resurfaced using a PG 58-28 binder meeting AASHTO M320, DENT, and Extended BBR specifications, however cracks formed within 5 years nonetheless. The focus of this study is to assess the performance of this road constructed using enhanced asphalt cement binder specifications and to investigate the causes of pavement cracks which have appeared. Original binder and recovered binder properties from the HL3 surface course after six years of field aging satisfied project specifications. Asphalt cement contents were sufficient and compaction requirements were achieved. Performance testing (rutting, fatigue, low temperature cracking, and dynamic modulus) on plant-produced mix indicated acceptable properties. As such, it was determined that asphalt cement properties did not adversely affect cracking. Upon further investigation, drainage issues arising from variable permeability within the granular and base materials appear to have contributed to the cracking on Battersea Road. Other factors included separation of the longitudinal centre line joint and differential settlement between widened bike lanes and the adjacent pavement. Good binder properties are essential but do not necessarily ensure cracking performance.