Soils are stabilized by compaction, taking water away from soils and adding material to the ground. The purpose of soil stabilization is to improve strength and durability for industrial projects, such as paving, building construction, railway laying and waterway improvements. Materials added to soils include lime, coal fly ash, Portland cement and foundry sand.
Compacting soil is accomplished by steamrollers, special compactors, grading machines and heavy equipment driven over the area. Compacting certain soils is necessary after desiccation to ensure that soil stabilization is more permanent. Making soil more dense reshapes whatever land is needed for projects.
Desiccating, or removing the water from soil, is done with chemicals such as lime. Coal fly ash and slag cement are added to clay to remove water before soil is compacted. Chemical reactions within the soil change the pH of dirt to allow faster drying times.
Adding material to the ground reduces the plasticity, or stretchiness, of soil. Foundry sand improves soil drainage, which aids in compaction. Additional gravel and other materials in soil change the way dirt is graded on its surface.
Materials that chemically alter dirt are often mixed with soil, reducing hauling and mixing costs. Reclamation machines dig up dirt, add material and then replace the soil. Graders then compact the material that was disturbed.