Case Study: Enhancing Runway Performance at Bangalore Airport with 63,602 SQM of Non-Woven Geotextile (200 GSM)

Ocean Non Wovens supplied 63,602 SQM of Non-Woven Geotextile Fabric (200 GSM) for the runway upgrade at BLR Airport (Kempegowda International Airport, Bengaluru), which handles over 33 million passengers a year. The work covered new taxiways and strengthening of the runway subgrade layers, and the geotextile went in as a separation and filtration layer between the subgrade and the granular sub-base.

Why geotextiles go under airfield pavements

Airfield pavements carry heavy aircraft wheel loads repeated thousands of times. The traditional answer to a weak subgrade is more granular material, which costs money and haulage. A non-woven geotextile at the subgrade level protects the granular layers that are placed, so they keep their designed thickness and strength.

• Separation: the fabric keeps the granular sub-base and the soil from mixing. Without it, fines push up into the aggregate under traffic and the aggregate punches down into wet soil, so the effective base gets thinner year by year.
• Filtration: water passes through the fabric while soil particles are held back, so the subgrade can drain without washing out into the base.
• Drainage: the needle-punched fabric also carries some water in its own plane, helping keep the subgrade surface from becoming waterlogged.
• Stabilisation: by keeping the base clean and intact, the fabric helps spread load and limit rutting. A 200 GSM non-woven is not a primary reinforcement; where reinforcement is needed, a geogrid is used.

The Bangalore Airport project

Scope

New taxiways and strengthening of runway subgrade layers at Bangalore International Airport. On an operating airfield, the materials had to perform reliably under heavy aircraft loads.

Product supplied

Ocean Non Wovens supplied 63,602 SQM of Non-Woven Geotextile Fabric (200 GSM), selected on tensile strength, puncture resistance, permeability and durability under cyclic loading.

Technical specifications of the geotextile used

Installation process

• Subgrade preparation: the soil was compacted and graded.
• Geotextile laying: rolls were unrolled with an overlap of 300 mm between sheets, the usual minimum for separation layers on a firm subgrade.
• Aggregate layering: granular sub-base (GSB) was placed directly over the geotextile. In general, aggregate is end-tipped and spread ahead of the plant so vehicles never run directly on the fabric.
• Quality assurance: on-site pullout tests and puncture resistance checks were carried out at random intervals.

Results and benefits

1. More uniform support: with the subgrade and sub-base kept separate, aircraft loads are carried more evenly and differential settlement is reduced.
2. Cost savings: reduced granular fill thickness gave material and transport savings, estimated at around 8–10%.
3. Faster construction: the fabric is quick to lay, even over undulating surfaces.
4. Drainage in the monsoon: the subgrade can shed water through the fabric without losing fines into the base.
5. Less excavation and fill: a thinner granular layer means less quarrying, haulage and earthwork.

Further benefits on airfields

• Less pumping: repeated wheel loads on saturated soil pump fines up into the base and eventually to the surface. The geotextile acts as a filter that stops this.
• Less foreign object debris (FOD): a base that stays intact cracks and ravels less at the surface, which reduces loose material that can be ingested by aircraft engines.

About Ocean Non Wovens

Ocean Non Wovens makes needle-punched non-woven geotextiles tested to ASTM and BIS standards, and provides technical support, on-site supervision and custom specifications. Beyond airports, the same fabrics are used in railway embankments and highway foundations, where IRC SP:59 covers geosynthetics in road pavements.

Explore our non-woven and woven geotextiles and other geosynthetics at oceangeosynthetics.com, see more case studies, or call +91 84472 26007 to discuss your airport or civil engineering project.