In this study, the first frost-heave testing apparatus with a triple cell was developed that can measure the amount of frost-heave and heaving pressure, as well as achieve high-accuracy temperature control. The performance of the apparatus was validated by a series of frost-heave tests, which were conducted in a closed system with saturated sandy soil and an initial boundary temperature of 3 °C. The effect of having multiple cells (triple cell, double cell, and single cell), different freezing directions (top to bottom, both sides, and bottom to top), and multiple temperature gradients (0.09, 0.11, and 0.13 °C/mm), was examined to investigate the frost-heave properties of sandy soil. The reliability of the testing machine was validated by comparing the measured (experimental) and estimated (theoretical) amount of frost-heave that occurs in saturated sandy soil. The results show that the newly developed testing device accurately estimates the amount of frost-heave with error of < 8.69% between predicted and measured results for heaving pressure with freezing direction from top to bottom.