The study looked at how the purity of lime affects the strength and durability of soil-lime mixes used for road stabilization. They found that while high-purity lime is recommended, lower purity lime can also work for certain types of soil. Silty soil can be stabilized with lower purity lime and still meet strength requirements, but clayey and black cotton soils need higher purity lime for durability. This means that the standard 70% purity requirement for lime can be relaxed for silty soil, making road projects more cost-effective.