Gas permeability measurements on asphalts using the electrodynamic balance

Volatilization, oxide degradation, and steric hardening are the degradation processes believed to be responsible for the weathering of asphalts. The fundamental mechanisms that govern the rates at which these degradation processes occur are not understood, but the transport of oxygen through the asphalt matrix is an important aspect of the weathering of asphalts under field conditions. Therefore, the measurement of diffusion, solubility, and permeability constants for oxygen in asphalts is crucial to better understand the long-term weathering of the asphalt materials. A novel and precise gravimetric technique, hitherto not applied in asphalt research is described here: an electrodynamic balance is used in this technique for the measurement of key transport properties for oxygen in micrometer-size asphalt particle samples.