EFFECT OF FREEZE-THAW CYCLING ON THE MECHANICAL PROPERTIES OF FIBER-REINFORCED CEMENTED SOIL

Freeze-thaw cycling is one of the main factors influencing the micro-structure and strength of fiber-reinforced cemented soil. A series of unconfined compression tests and freeze-thaw tests were conducted on basalt fiber-reinforced cemented clay specimens to investigate the effects of the number of freeze-thaw cycles, the curing time and the fiber length. The results showed that the strength of cemented soil continued to increase with increasing curing time. The strength of cemented soil was improved when the fiber was added. As the number of freeze-thaw cycles increased, cracks began to appear on the surface of the cemented soil. Obvious cracks appeared on the surface of the cemented soil without fiber after being subjected to 3 freeze-thaw cycles. Then, penetrating cracks appeared in the cemented soil without fiber, and the cemented soil completely lost its bearing capacity after being subjected to 6 freeze-thaw cycles; in contrast, cracks began to appear on the surface of cemented soil with fiber after being subjected to 6 cycles. As the number of freeze-thaw cycles increased, the strength of the fiber-reinforced cemented soil tended to decrease. The strength of cemented soil without fiber decreased the most. The relationship between the strength and the number of freeze-thaw cycles was linear. With the increase of the number of freeze-thaw cycles, the fiber length had less and less influence on the strength. The research indicated that the strength of cemented soil could be effectively improved when fiber was added. Although the strength of a fiber-reinforced cemented soil decreased as the number of freeze-thaw cycles increased, the strength loss decreased, and the frost resistance of a cemented soil was improved when the basalt fiber was added.