In the past, when dealing with difficult sites for construction purposes, the conventional practice has been limited to either replacing unsuitable soils with other more suitable materials, or bypassing these soils with costly deep foundations. Further, the problem of land scarcity, the need to rebuild ageing infrastructure in urban areas, increased incidents of seismic hazards, and environmental regulations have given an impetus to the evolution of a number of ground improvement techniques. Innovative ground modification approaches are now used to solve unique soil-related problems and are often considered to be the most economical means of improving an undesirable site condition.
Geosynthetics, which are technical textiles related to soil, rock, earth, etc., have proven to be among the most versatile and cost-effective ground modification materials in the long run. Their use is expanding into nearly all areas of civil, geotechnical, environmental, coastal and hydraulic engineering. Although advanced economies in North America and Europe have traditionally led the demand for technical textile products, emerging economies are expected to take the lead in the coming years. India’s share in the global technical textile market has registered a significant increase over the past decade and will continue to increase owing to the regulatory push to the technical textiles industry.
Based on their physical characteristics and subsequent applications, geosynthetics are classified into woven and non-woven geotextiles, geogrids, geomembranes, geonets, geofoams, geosynthetic clay liners, geopipes, etc. The geosynthetics industry is mainly constituted of woven and non-woven geotextiles accounting for 85 per cent of the market. In India, the geotextiles market has grown at a significant rate of 30 per cent in the past five to six years. Major players including Garware Wall Ropes, Techfab India, Kusumgar Projects, Strata GeoSystems and Skaps Industries dominate the geotextiles landscape in the country. Some new players such as Manas Geotech and Supreme Nonwovens have also started providing wide width polyester-based non-wovens for users in infrastructure sectors. International companies such as Fibertex Nonwovens, Maccaferri India, Tencate, Terram and Huesker are also marking their presence.
Advances in the technical textile industry are helping enhance productivity and reduce costs for end-use industries. The average weight of the buildtech material used in the construction of a standard building is about 1/30th the weight of brick, concrete or steel materials as it needs less reinforcement, thereby optimising costs.
Geosynthetics are being used for all conceivable situations in civil engineering and infrastructure projects – roads and expressways, airport runways, embankments for railways, dams, canals, flyover embankments, seaside platforms, retaining walls, etc. However, despite their inherent performance-enhancing qualities, the use of geosynthetic materials in India has been slow to pick up due to low awareness of their utility vis-à-vis conventional materials.
Roads built on soft and expansive soil subgrades suffer from many problems and deteriorate quickly. Investigations on failures of such roads reveal that one of the major causes of failure can be attributed to penetration of fine- grained soils in the base of the pavement structure leading to improper drainage and loss of support. In hilly areas, erosion of slopes often leads to catastrophic landslides, disrupting road networks. To overcome problems associated with soft ground and soil erosion, geosynthetics have become an increasingly important construction material.
Sector-wise, the application of geosynthetics in the transport sector has increased significantly, as they increase the strength and stability of the underlying soil in roadways and railway tracks. As per industry experts, the road sector accounts for the majority share in the use of geosynthetics in the country at about 40 per cent. Among geosynthetic products, the sector primarily uses geogrids, which are used in road works for creating slopes/slope rehabilitation, widening pavements, controlling erosion control, and improving filtration and drainage. As per industry estimates, every 15-20 km of road length under the National Highways Development Programme has at least one elevated structure and experts are of the opinion that 5,000-10,000 square metres of geogrids are required for each of these structures. Notably, the road sector accounts for 70-80 per cent of the geogrid market. Besides the transport sector, geosynthetics are also extensively used in the construction of dams and embankment canals, drainage works, irrigation, solid waste management and soil erosion prevention in coastal areas and riverbanks.
The growth in the use of geosynthetics in mining activity is due to its ability to resist the harsh environment they are exposed to. On mining sites, geomembranes are used primarily for liquid containment (drainage water, process solutions and treatment ponds) as basal liners. Geogrids are used to stabilise soft soils present on the upper layers and mine tailings for soil cover placement. Geopipes are used for conveying drainage water, runoff and process waters, and for leak detection around mining sites. Geotextiles are used as cushion layers to prevent abrasion of metals. They are also used to filter by-products. With the ever-increasing requirements of metals and fuel, mining activity has grown over the years, and this, in turn, has led to an increase in the amount of geosynthetics being used.
Considering the country’s vast road network, geosynthetics surely have far-reaching and diverse applications. The overall demand for geotextile materials is expected to grow due to its cost-effectiveness over the product use life cycle. Further, the use for reinforced walls, road underbridges and road overbridges is also on the rise, thereby increasing the demand for geotextiles, especially since geosynthetics retain enhanced performance in all terrain and weather conditions.
New tracks for dedicated freight corridors and high speed bullet trains are already planned for implementation by 2022. This opens up huge opportunities for increased consumption of geotextiles. In addition to the increased use of geotechnical materials by the defence and military sectors, other new and promising areas that could open up the demand for geosynthetics are inland water transport system, inter-basin water transfer, flood control via use of geobags, and landfills.
Despite the many benefits, geosynthetics’ penetration in the construction sector is still low. Some issues are that a large number of civil engineers are still not very familiar with these products; there is very limited coverage of geosynthetics by most Indian standards, codes of practice and specifications; lack of good testing facilities in the country; and very limited funding for research and development.
The government’s flagship Make in India policy initiative identifies the technical textile industry as a sunrise sector, pegging its value at $17 billion in March 2018. The potential of the sector is being harnessed through measures such as tax breaks, special financial packages and allowing 100 per cent foreign direct investment. Other initiatives include the establishment of dedicated centres of excellence for research in technical textiles, reduction in custom duty rates from 5 per cent to 2.5 per cent on select high performance specialty fibres, and a 15 per cent subsidy on capital investment subject to a ceiling of Rs 300 million for entrepreneurs over a period of five years. Policymakers are also facilitating the industry’s growth by implementing a strategy that mandates the use of technical textiles in end-use industries. The government’s ambitious pledge to eliminate single-use plastic in the country by 2022 is one such step.
For the country’s geosynthetics industry to realise its true potential, policymakers need to make conscious attempts to streamline regulations and focus on the widespread application of geosynthetic products. Besides, the build-operate-transfer system needs to be modified to design-build-operate-transfer to lay emphasis on the initial design of a project for using geosynthetics. These measures will give a boost to domestic production and reduce the ongoing large imports. Moreover, the government must invest more in technology and manpower upskilling to enable product innovation in the sector and adherence to global quality norms.