Modified test research of saline soil roadbed padding for highways in coastal areas

In view of the adverse engineering characteristics of saline soil such as collapsibility, salt expansion and corrosion, cement, cement-lime and KD curing agent have been respectively used to modify the saline soil in the coastal areas for engineering application. Unconfined compressive strength test of the modified soil has been conducted to analyze the reasons why the two previous modified materials can\´t address the engineering needs. With the local hydrogeological conditions taken into considerations, the effects of modification with KD curing agent under the philosophy of "ignoring chlorine but controlling sulfur, and restraining expansion with strength" have been studied. A large number of lab studies indicate that the unconfined compressive strength of the saline soil modified with 3% KD curing agent is over 1.5 MPa, and its CBR is up to 26% (more than 10 times of that before modification), which is far above 8%, the requirement of the national standard for CBR of road embankments and beds. Also, its index of plasticity is in the range of 10 <; I_p <; 18. The experimental results show that the saline soil modified with KD curing agent provides the relatively high strength, outstanding water stability, and great road performance indices that meet the relevant specifications, and can be used as roadbed filler.