Geosynthetics find applications across most, if not all, infrastructure sectors. They have several advantages over traditional materials such as comparatively lower land requirement, safer design and additional structural strength. They also have an aesthetically pleasing appearance and blend well with the surroundings. The wide range of products offered under the geosynthetics umbrella makes them suitable for widespread application across infrastructure sectors. Going forward, the rapid expansion in infrastructure development is expected to drive the demand for geosynthetics.
The construction of roads requires geotextiles, which are permeable textile materials made from polypropylene or polyester. They are used in civil engineering for erosion control, soil stabilisation, reinforcement, separation and drainage. The road sector in India is a major consumer of geotextiles.
The government is undertaking large investments in the development of roads. A priority sector for the government, it aims to spend Rs 5 trillion-Rs 6 trillion in the sector in the next four to five years. Many key road projects currently being developed use geosynthetics extensively. For example, the Koilwar-Bhojpur (II) project in Bihar under the National Highways Development Programme (NHDP) is using geotextiles. Thus, with a number of projects being announced under the NHDP and the Bharatmala Pariyojana, the demand for geotextiles is expected to grow strongly.
Geosynthetics find use in the railway sector for track bed stabilisation, track drainage, erosion control, interface protection, construction over soft soils, steep slope construction, mud pumping, etc. The government has set a capex target of Rs 1.48 trillion for 2018-19 on railway infrastructure upgradation and capacity creation.
Dedicated freight corridors and high speed corridors are also being planned. These will entail heavy axle loads and will require railway tracks with stable track formation, which can be provided using geosynthetics. The Cabinet Committee on Economic Affairs has recently approved the 425 km long Jhansi-Manikpur and Bhimsen-Khairar line doubling and electrification projects which will entail substantial deployment of geosynthetics.
The construction of runways and reinforcing pavements require extensive application of geosynthetics to provide a smooth and even surface. Steep reinforced embankments or gabion walls are used to provide the flat area for runways and other airport infrastructure.
The Kolkata airport runway was developed using non-woven geotextiles for runway base stabilisation. The main issue faced was the rainfall drainage associated with the heavy monsoons. There was a need to minimise the erosive effect of water flowing under the pavement. The substrate comprised mixed materials (clays and sands) and featured good compression resistance.
A non-woven geotextile capable of simultaneously serving the three purposes of separation, filtration and drainage was used to rebuild the runway. A blend of fibres of a specific linear density was used to achieve superior permeability performance on the geotextile surface. Drainage pipes were also installed every 20 metres to increase drainage capacity of the system considering the heavy rainfall during the monsoons.
The need for environment-resilient infrastructure along India’s coastline will drive the demand for geosynthetic products. Coastal areas are dynamic with unique geomechanical features such as soil instability and soft soils leading to a weak foundation. This creates the requirement for geosynthetics to provide soil stability. States requiring significant amount of investments in geosynthetics such as gabions, geobags, etc. are Odisha, Tamil Nadu, Maharashtra, Kerala and Andhra Pradesh which would see significant development in the port sector.
Tunnel construction in India has shown a growth trend in recent years with a greater impetus being given to key infrastructure projects in the hydro, railway and road sectors. This will be a key demand driver for geosynthetics. According to India Infrastructure Research, 704 tunnels in various sectors covering 2,847 km are to be taken up in the coming years creating significant demand for geosynthetics. These materials are extensively used in sealing systems in tunnels as they reduce corrosion and add structural strength.
During the past three decades, the geosynthetics industry has developed a variety of materials that are useful in the development of irrigation and drainage projects, particularly for controlling seepage and erosion. Geosynthetics now provide options for the design and construction of low embankment dams, cost-effective solutions for slope and channel protection, and long-term solutions for the control of seepage losses from reservoirs and channels. Today, there are geosynthetic materials available that meet project specifications and have durability consistent with the project design life thus ensuring a long life for the project.
The government has set a production target of 1 billion tonnes for Coal India Limited (CIL) by 2020. The major geosynthetics applications in coal operations are for environmental contamination controls such as erosion control materials, silt fences and sedimentation pond liners. Mine safety applications and mechanically stabilised earth (MSE) stabilisation berms and final cover for coal spoil tips also use geosynthetics.
For oil and gas companies, geosynthetics are used in the construction of paved and unpaved roads to access well sites and storage locations. Geomembrane liners are also used at well sites to control surface contamination and as secondary liners for storage tanks and tank farms.
The construction and operations of renewable energy projects require the application of many geosynthetics such as geotextiles and geogrids. High strength geosynthetics are used for providing foundation support and stabilisation of concrete footings in wind and solar energy projects. Geosynthetics are also used for the construction of MSE walls and slopes using reinforcement which provide the level surface required in these projects.
For hydropower projects, geosynthetics are used for clay liners. Geomembranes are also used on the upstream face of earth fill, concrete and roller compacted dams. Geonets, geocomposites and geotextile drainage materials are used between the dam and the waterproofing geomembranes.
Nuclear power systems use geomembranes, geosynthetic clay liners, drainage geocomposites and geotextiles for operating waste disposal double-lined systems with leak detection capabilities. Geomembranes are also used as vertical cut-off walls for lateral confinement of contaminated groundwater seepage and for lining of disposal boxes containing low-level radioactive waste such as contaminated equipment, construction and demolition waste.
The way forward
With the government planning massive infrastructure development in the next 5 to 10 years, the demand for geosynthetics in India is expected to get a significant fillip. The Indian geosynthetics market is expected to grow from 125 million square metres in 2014 to 186 million square metres in 2022, at a compound annual growth rate of 5.1 per cent. Thus, the outlook for geosynthetics market in India looks bright.