Development of internal structure of polymer-modified asphalts via transformations of the reduced frequency

摘要

The independent variable of dynamic material functions and corresponding master curves, the reduced angular frequency omega over bar , was transformed into the apparent molecular weight MW*. As a function of MW*, the normalized master phase angle represented an apparent cumulative molecular weight. This function's numerical differentiation yielded the probability density function of the apparent molecular weight, f(MW*). While this procedure is unproblematic in conventional (straight run) asphalts, it is yielding peaks of negative MW* in polymer modified asphalts. Thus reduced frequency was also transformed to the temperature, which allowed us to determine that the apparent glass transition temperature as the maximum on the master curve of loss modulus G"(T). The master curve of the normalized phase angle as a function of temperature helped to explain the phenomenon associated with the probability density function in modified asphalts. The results presented in this article were obtained numerically, without the use of rheological models.