Effect of freeze–thaw cycles on mechanical property of silty clay modified by fly ash and crumb rubber

• A specific freeze–thaw testing apparatus was designed, manufactured and applied.
• Silty clay modified by fly ash and crumb rubber is proposed as anti-freezing layer.
• Effects of freeze–thaw cycle, temperature and load frequency on modulus of modified soil were demonstrated.
• Comparative analysis with silty clay was conducted.

In seasonal frozen regions, freeze–thaw cycle is a weathering phenomenon which has great influence on engineering properties of soils. Material selection and its evaluation of freeze–thaw effect are important to guarantee subgrade stability. In this paper, a freeze–thaw testing apparatus is designed and manufactured. This apparatus can realize the measurement of strain, stress and temperature of samples and more realistically simulate the road structure. Silty clay modified by fly ash and crumb rubber is used as anti-freezing layer of subgrade. Experimental modulus is measured to evaluate the mechanical property of modified soil through the freeze–thaw testing apparatus. Effects of freeze–thaw cycles, temperature and dynamic load frequency on modulus are investigated and discussed. Comparative analysis is conducted with silty clay, it reveals that modified soil possesses more favorable mechanical performance.