Effect of Basalt and Polypropylene Fibers on Unconfined Compressive Strength of a Cement-Stabilized Clay Soil

In the current study, the polypropylene fiber (PPF) and basalt fiber (BF) were used to enhance the shear strength of natural soil or cement stabilized soil specimens. The main objective of this research is investigating the effect of curing time, initial moisture content and PPF or BF with or without the addition of cement on the unconfined compressive strength (UCS) of clayey soil. It is found out that adding cement, PPF or BF to soil causes a remarkable increase in the UCS value. The UCS value of the PPF-reinforced specimens was observed more than that of BF-reinforced specimens. The UCS of specimens increases gradually as the cement content or curing time increases. However, the axial strain at failure for cement-stabilized specimens decreased with the increasing curing time. Furthermore, it is concluded that the increase in the UCS of combined PPF or BF and cement inclusions is much more than the increase caused by them, individually. The fiber-reinforced specimens show a more ductile behavior than the natural soil or cement-stabilized specimens. The inclusion of fibers within the cement-stabilized specimens reduces the brittleness of the response and increases the UCS and axial strain at failure, significantly. The increase in the UCS of combined fiber and cement specimens is much more than the increase caused by fiber or cement, individually.