Frost-Heaving Pressure and Stiffness of Compacted Roadbed Material by Laboratory Model Test

The laboratory model test was carried out in the freezing chamber and the size of insulated steel box is 0.9 m(L) × 0.9 m(B) × 0.9 m(H) which simulated actual roadbed structure. Data logger was used to measure the variation of temperature. The variation of heaving pressure with elapsed time for various roadbed conditions was determined through the laboratory model test. The influence of crushed natural aggregate to the freezing of the subgrade soil was studied to verify the function and effectiveness of the anti-freezing layer. The thermal gradient is greatly influenced prior to reach the soil temperature of 0 ℃ or below 0 ℃. The heat transfer rate is greater at the roadbed surface and then slightly decreases with the depth of roadbed. The degree of air temperature and the type of soil layer are also influenced on the freezing temperature (0 ℃) at the roadbed depth. On the other hands, the anti-freezing materials like crushed natural aggregates can reduce the event of frost heaving of subgrade soil at the same condition of soil density, temperature, and moisture content. The loading pressure and deflection for the compacted roadbed materials prior to freezing and after thawing and hence, the modulus of elasticity were determined by the application of the light falling weight deflectometer (LFWD).