Abhishek Gupta, Assistant Vice-President, ICRA Limited-
The construction sector in India has evolved over the years in terms of the adaptation of new technologies, materials, and processes. Geosynthetics are one such product category which has grown in significance in the sector. It signifies a family of civil engineering materials made of synthetic (such as polypropylene and polyester) or natural polymers (rubber, jute and coir). They are used to improve specific applications in geotechnical and geoenvironmental engineering like ground stabilisation, reinforcement, etc. The polymeric nature of the products makes them suitable for use in the ground where a high level of durability is required.
There are eight main categories of geosynthetics: geotextiles (woven and non-woven), geogrids (flexible and rigid), geonets, geomembranes, geosynthetic clay liners, geofoam, geocells and geocomposites. Geosynthetic products are used for five main categories of applications: separation (partitioning of two adjacent but dissimilar materials to prevent intermixing), reinforcement (strengthening of soil slopes, reinforced earth walls for bridge approaches, construction on soft soils, pavement layers, etc.), filtration, drainage facilitation, and containment (liquid and gas barriers).
Applications of geosynthetics
Geotextiles, geogrids and geomembranes are the three more commonly used products in terms of volume and value. With regard to their usage in infrastructure, they find applications in sectors such as roads, railways, water, oil and gas, ports, waste handling, etc. However, roads and railways are the two primary areas of applications for geosynthetics globally. In road and railway projects, geosynthetics are used for erosion control, drainage, reinforcing soil walls, etc. Their use is particularly important in areas with high soil erosion, floods, hilly terrain, etc.
Geosynthetic products provide overall benefits in terms of better efficiency, reduced project implementation time, longer project life and lower carbon footprint. These benefits justify the initial higher cost of certain geosynthetics in comparison to natural construction materials (like aggregate, sand, asphalt, etc.) over the life of the project.
Market size and growth drivers
While geosynthetic products have been in existence for over five decades, globally their use has picked up only over the past two decades with sizeable demand coming from the Asia- Pacific, particularly China. As per estimates by Grand View Research, Inc., a US-based market research and consulting company, as of 2014, global volumes for geosynthetics were over 6.1 billion square metres and are projected to reach 9 billion square metres (worth about $27 billion) by 2022. Of the total global volume of geosynthetics in 2014, the Asia-Pacific accounted for over 35 per cent or 2.1 billion square metres (worth $6.1 billion). Demand is growing at an even faster pace led by increasing demand from China and India.
The size of the Indian geosynthetics market is relatively modest with estimated volumes of 130 million square metres in 2014. However, the volume growth for the Indian geosynthetics market is expected to be much higher than the global average with demand projected to double between 2014 and 2020, compared to an about 5 per cent growth expected for global geosynthetics volumes. The growth in India is expected to be driven by infrastructure projects in the road, railway, irrigation and water harvesting segments.
India is amongst the world’s largest countries in terms of its road and railway network. The majority of the roads in India have flexible pavements, which can benefit from geosynthetics for the stabilisation of their foundation. The government has huge investment plans for construction and the upgradation of roads and railways, which can boost the demand for geosynthetics significantly. With many road projects being undertaken on the public-private partnership model, which has a long concession period, the life-cycle benefits from the use of geosynthetics are expected to outweigh the higher initial cost. Further, new road projects awarded on an engineering, procurement and construction basis have a built-in clause for the maintenance of the road for a certain period (generally two to four years) post the completion of construction. Many road projects in India, particularly in difficult soil terrain, have used geosynthetics. The material is also beneficial in regions which have limited aggregate or sand supply as the transportation of these raw materials over a long distance can be very costly. In comparison, geosynthetics are lighter and easier to transport.
Indian Railways (IR), however, has thus far used geosynthetics only sparingly, due to a lack of Indian standards on these products. Nevertheless, recently IR has started looking at using geosynthetics for improving track quality for high speed trains, particularly in poor soil or rocky terrains. With the increasing focus on the high speed rail segment, strengthening of portions of the existing track will be required, which could be done with the help of geosynthetics. With increased awareness of the advantages provided by such products, geosynthetics use in India is expected to increase.
Key challenges ahead
While geosynthetics provide overall benefits in terms of faster speed of construction, lower maintenance requirements and environment conservation, their adaptation/adoption in India has been quite low so far. Key reasons include low awareness of benefits, and a lack of technical expertise, trained engineers, technical standards and adequate research on applications of such products as per local conditions, the availability of low-cost substitutes, as well as high volatility in prices of geosynthetic products (being a derivative of crude oil). Sometimes, perceptions about the durability of geosynthetics and damage to the environment due to their degradation are also causes for concern.
Increasing application of natural geotextiles
In India, the use of geosynthetics is also constrained by its relatively high costs compared to alternative materials. However, given the significant benefits of geosynthetics in many fields, alternatives in the form of natural geotextiles have found greater acceptance. However, as natural geotextiles are biodegradable, their use is generally limited to areas which require short-term reinforcement till the time the natural vegetation grows and becomes strong enough to hold the soil. These natural geotextiles find applications in the control of soil erosion, stabilisation of slope and river embankments, subsurface drains, etc.
Natural geotextiles are agro-based and generally derived from jute, coconut coir, straw, rubber, etc. Jute-based geotextiles have found support from the government in an effort to utilise jute production. In March 2015, the Government of India launched a scheme for the promotion of jute-based geotextiles in the north-eastern states, with a total outlay of Rs 4.27 billion. Similarly, some state governments have also promoted the use of natural geotextiles for the construction of rural roads under the Pradhan Mantri Gram Sadak Yojana.
Besides lower costs, the advantage associated with these geotextiles being renewable products with no environmental damage, their use is expected to gain pace. However, in applications where durability is required, synthetic geotextiles are expected to be of greater benefit than natural ones.
The way forward
The application of geosynthetics provides significant benefits over the project life cycle, in the form of speedier execution, lower maintenance and longer project life. Geosynthetics have a significant advantage over alternatives in regions with high soil erosion and extreme weather conditions, like floods, etc. However, there are many inhibiting factors such as low awareness, a perception of low durability and high costs, which result in the lower use of geosynthetics in India.
While the government has taken steps to promote the use of natural geotextiles and many regulatory bodies have taken up the cause to explain the benefits of geosynthetics, a lot more still needs to be done for better adaptability/increasing adoption. As the benefits associated with geosynthetics depend on the correct choice of material, design and technique, establishing standards/codes in this regard could be a major support. Similarly, promoting research and development, training, certification, etc. can further strengthen awareness about and the acceptability of geosynthetics. Moreover, studies on the performance of projects using geosynthetics in terms of maintenance and durability would help in establishing the associated cost benefits, which can, over time, help in the adoption of superior technologies and materials for sustainable infrastructure development.