Non-woven Geotextiles for stabilization of Roads and Highways

Geotextiles, a class of geosynthetics, are widely used to stabilise roads and highways. They act as a separator, a filter and a reinforcement layer, and they are now a standard part of road construction on poor ground. Ocean Geosynthetics supplies geotextiles for roads, railways and other transport work.

India has the second-largest road network in the world. The national highway network alone had grown to about 1,37,625 km by March 2021, and in FY 2020-21 highways were built at a record pace of about 37 km a day. Modern highways have to carry heavier axle loads and more traffic, and they need efficient drainage to last.

What are Geotextiles?

Geotextiles are permeable fabrics used in civil, geotechnical and geo-environmental engineering. They are usually made from biologically inert polymers such as polypropylene and polyester, so they do not rot in the ground. Geotextiles can be woven, non-woven or knitted.

The role of Geotextiles in Road Stabilization:

A geotextile laid on a soft subgrade keeps the stone sub-base from punching into the soil and the soil from pumping up into the stone. The aggregate stays clean and keeps its strength, and higher-strength grades add some reinforcement as well. Depending on the subgrade and the geotextile used, the granular layers can sometimes be made thinner. Non-woven geotextiles are the type most commonly used in road construction.

In asphalt overlays, a non-woven paving fabric slows the reflection of old cracks into the new surface and blocks surface water from reaching the base, so roads last longer and develop fewer potholes. Geosynthetics are quick to install, often cost less than thicker conventional layers, and let engineers build on ground that was once considered too difficult.

The Process:

Geotextiles are delivered to site in rolls. In new construction their main jobs are to separate the subgrade from the sub-base or base, and to reinforce soft soils so they give a firm platform.

Permeable pavements work differently. There, a woven geotextile or non-woven separation fabric is often placed between the subgrade and the open-graded stone sub-base, so fine soil cannot migrate into the stone and clog the pavement’s water storage.

For a paving fabric under an asphalt overlay, the existing surface is first cleaned, cracks are cleaned and sealed, and potholes and other distress are repaired. The surface is then ready for the non-woven geotextile.

A bitumen tack coat is sprayed first, and the non-woven fabric is laid onto it by hand or by machine. The fabric is broomed and pneumatic-rolled to bed it into the tack coat, and the overlay is then placed.

A non-woven geotextile on its own is highly permeable, but once it soaks up the tack coat it forms a nearly impermeable interlayer, which is what protects the base from water. Its thickness and rough surface also hold the bitumen and bond well to both layers. When choosing a paving fabric, check its mass per unit area, thickness, tensile strength and asphalt retention. A project’s results depend on both the material’s strength and correct installation.

Geotextiles have high tensile strength, do not rot, and are chemically and biologically inert. They resist UV for the short exposure during construction but should be covered promptly. Used properly, they help roads and highways last longer by keeping the aggregate layers strong and well supported.

Ocean Geosynthetics supplies a range of geosynthetics products for civil engineering projects, including woven and non-woven geotextiles for roads and highways. Our products go through quality control testing before dispatch.