Typar® Spunbound Geotextiles create a layer of separation that develops a graded aggregate filter layer in the subgrade soil to maintain separation and eliminate the risk of soil mixing or ‘pumping’. TYPAR promotes development of such filter layers due to its unique bonded fibers that create a pathway resembling a well-graded aggregate filter. TYPAR provides an effective filter structure since it has both high permeability, which will not change under compaction, and the ability to retain soil particles adjacent to it, minimizing the piping of subgrade soils and reducing fine particles from crossing the filtration layer.
The prevention of mixing of valuable base aggregate with underlying subgrade soils enhances drainage of the subgrade while preventing pumping of fine soil particles into the base aggregate, which reduces the required amount of base aggregate and assures long-term prevention of base deterioration.