An apparatus for measuring cement expansion comprises an expansion cell that comprises two nodes separated by a slit. The nodes are separated by a distance such that a change of the distance between the nodes may be correlated to a linear expansion of cement contained in the expansion cell. An electrical component is coupled to the two nodes, and the electrical component has an electrical property that may be correlated to the distance between the nodes. Measurement of the electrical-property change may be performed continuously and in real time. In addition, the expansion cell may be placed in a vessel equipped to simulate downhole pressure and temperature conditions.