Onsite Use of Recycled Asphalt Pavement Materials and Geocells to ...

Separation. Separation is the introduction of a flexible geosynthetic sheet between two
dissimilar materials so that the functions of both materials are maintained. The geosynthetic
works as a separator which prevents the intermixing of dissimilar materials, thus maintaining the
design thickness and roadway integrity of two different layers such as sub-base and subgrade in
roadways. The separator prevents granular particles in bases from penetrating into subgrade, and
fines in subgrade from migrating into permeable granular bases. Geotextile and geomembrane
are commonly used as a function of separation in roadways.
Filtration. Filtration via a geosynthetic consists of movement of liquid through the
geosynthetic and a resulting retention of fine particles of soil. Geotextiles are the geosynthetic
products commonly used for filtration purposes. Geotextiles are used to prevent the movement of
fine particles from soft subgrade to granular bases, thus maintaining the design thickness and
roadway integrity. Geosynthetics have been used for their filtration function in roadways,
landfills, retaining walls, and slopes, etc.
Drainage. Geosynthetics perform a drainage function by transmitting the liquid within
the plane of the structure. The geosynthetics generally used for drainage purposes are
geocomposites and geotextiles. The geosynthetics have been used to dissipate pore water
pressures at the base of road embankments, exposed soil or rock surfaces, retaining walls, dams,
and reservoirs, etc.
Reinforcement. Geosynthetics can be used as a reinforcing element within a soil mass to
produce a composite that has improved strength and deformation properties over the
unreinforced soil. Geogrid, woven geotextile, and geocell are the geosynthetic products
commonly used for reinforcement of soil to provide tensile strength and stiffness and lateral
confinement.
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