The particles aggregation states and apparent volume of the stacked glass beads at different liquid content are studied experimentally. It shows that the liquid mainly exist as liquid bridges at low liquid content

while that in different pores connects to each other at higher liquid content. The apparent contact angle of water on particle surface determines the critical moisture content which separates the low and high moisture content. The transformation of liquid morphologies induces the variation of the liquid action on particles

which finally influences the particles aggregate state and leads to the change in the sample apparent volume. A model is developed to determine the critical liquid content by the apparent contact angle

from which the liquid begins to mainly exist as interconnectedness morphology other than isolated liquid bridges. The prediction from the model is in good agreement with the experimental data.