Soil modification changes the physical characteristics of soils by mixing in an additive such as quicklime. The primary goals are to reduce the shrinking and swelling capability by reducing the plastic index (PI), increase load bearing capacity, and drying soils to improve workability and achieve compaction.
As with stabilization, the main benefit is saving time, money, and reducing the environmental impact. There is no need to excavate and replace onsite soil which dramatically reduces the amount of trucking and time spent placing new soil.
Various amendments can be added to the soil to modify its properties. Common amendments include lime, cement, fly ash, organic matter (such as compost), and chemical additives. These amendments can improve soil structure, increase strength, reduce plasticity, enhance drainage, and promote compaction.