Elastic modulus measurements are often required to evaluate the structural performance or to estimate the damage in cement-based materials. The axisymmetric flexural vibration (AFV) of a thick circular disk is a test method that can be used to estimate the dynamic elastic modulus of cement-based materials. Cement-based materials are inherently nonlinear materials and their nonlinearity increases with damage. The main objectives of this paper are to investigate the consequences of material nonlinearity on the AFV measurements, and to understand the implications of the change of material nonlinearity with damage on these measurements. In this work, experimental measurements are performed on mortar specimens damaged by freeze-thaw. Acoustic emission is used as a benchmark method to monitor and quantify the damage.