Page 158 - MODELING OF ASPHALT CONCRETE

136 Cha pte r F i v e

FIGURE 5-9 Poisson’s ratios at (a) −10°C; (b) 10°C; and (c) 35°C. (Kim et al. 2004, with permission
from Transportation Research Board.)

obtained from the axial compression and IDT testing of 24 commonly used North
Carolina mixtures.
It was also found that Poisson’s ratio is a weak function of loading frequency.
This frequency dependence of Poisson’s ratio results in different phase angles,
depending on whether the horizontal strain or the vertical strain is used. An
average of these two phase angles yields similar values to the axial compression
phase angle.
The findings presented in this chapter provide the analytical solutions that may
be used in a standard test and analysis protocol for the determination of dynamic
modulus and phase angle mastercurves of asphalt mixtures using the IDT test. This
protocol will be an essential means of using the dynamic modulus in forensic
analysis that utilizes the mechanistic principles in the NCHRP 1-37A Guide for
Design of New and Rehabilitated Pavement Structures developed under the NCHRP
project 1-37A (2004).