Co-Investigators
-
Jialiang Le, Associate Professor, Civil, Environmental and Geo-Engineering
Summary
Increasing the durability of materials represents a key component in the development of a sustainable pavement infrastructure in Minnesota that is well adapted to the climate and funding changes of the future. While significant effort has been dedicated to the pavement design component, focusing on the damage induced by traffic, less effort has been dedicated to investigating the durability of asphalt materials, especially related to low-temperature cracking, which represents the most significant distress in asphalt pavements in the state. Low-temperature cracking is primarily a result of high tensile stresses that develop during cold temperature events combined with continuous aging of pavements during service life. In recent years, a number of new construction technologies have emerged as potential tools to improve the durability of asphalt materials. A prime example is warm mix asphalt (WMA) that can be mixed and compacted at lower temperatures, which lower the emissions generated at the mixing plant, and at the same time, reduce the short-term aging of asphalt materials, therefore increasing their resistance to thermal cracking. WMA mixtures are also more compactable, which makes them an ideal candidate for increasing density, and therefore durability, and for extending the cold paving season in fall. The current asphalt binder specifications do not fully address the binder resistance to low-temperature cracking, due to significant changes in binder formulation and improvements in laboratory characterization capabilities. In a current study (NCHRP Project 09-60), the research team (which includes the PI of this project) has proposed a new set of parameters to improve the selection process of asphalt binders with increased resistance to low-temperature cracking. The main objectives of this project are to provide a comprehensive literature review of current tools available to increase asphalt pavement durability; perform a detailed evaluation of WMA technology and of the newly proposed binder specifications, based on laboratory experiments and data analysis; and provide preliminary guidelines for integrating them in the current practice of asphalt paving in Minnesota.