A Study of Physical Factors Affecting the Durability of Asphaltic Pavements. Void Parameters Affecting Asphalt Concrete Durability

摘要

The purpose of the investigation was to evaluate the effects of the air permeance and air void content on the durability of asphalt concrete as measured by asphalt hardening. The investigation involved: the preparation of asphalt concrete samples from a single design mixture at various levels of compaction, the testing of those samples for air voids and air permeability, the aging of those samples in a controlled environment in order to promote asphalt hardening, and the testing of those samples at various aging times to determine the extent of asphalt hardening as measured by changes in penetration, absolute viscosity, and percent asphaltenes. At least two types of asphalt hardening are associated with asphalt concrete. Each type of asphalt hardening is associated with a particular air void system. The amount of each type of asphalt hardening is dependent on the size of the air void system to which it is related. The larger the air void system the greater the amount of hardening. It was concluded that asphalt hardening as measured by changes in penetration and by changes in percent asphaltenes is dependent on the portion of the total air void content that is accessible to air and that asphalt hardening as measured by changes in absolute viscosity is dependent on the portion of the total air void content that is not accessible to air. (Author)