India is expected to invest $5 trillion in infrastructure by 2040, approximately 30 per cent of which will be invested in the next five years. Despite the big plans, the construction industry is hampered by a plethora of challenges. The lack of a skilled workforce, indiscriminate use of natural resources, low level of technology adoption, non-availability of land within city limits, shortages of sand and water, etc., are some of the key issues being faced by contractors. These issues are the biggest causes of time and cost overruns impacting road projects.
While digitalisation has made inroads into several sectors, its adoption in the construction industry has been slow. This is despite the fact that the industry contributes 8-9 per cent to the country’s GDP. Besides, the acceptance and deployment of unconventional construction materials has been quite sluggish. Nevertheless, the government has shown a positive intent towards increasing digitalisation and the use of alternative construction materials, and is continuously striving towards increasing its penetration.
New technologies being deployed
In light of the various challenges faced by the construction industry, organisations have begun to digitalise their internal processes. They are moving towards a common data environment for expediting project delivery and the creation of digital twins. The key emerging technologies in the engineering and construction segment include pre-fabrication and modular construction, augmented reality and virtualisation, cloud and real-time collaboration, 3D scanning and photogrammetry, and building information modelling. In addition to reducing risk and increasing efficiency, the adoption of these technologies is expected to result in better monitoring of projects in the design and construction stage, thereby ensuring timely completion within the stipulated budget.
The National Highways Authority of India (NHAI) has adopted some highway construction technologies that are being deployed globally. For better project planning, NHAI is in the process of implementing geospatial network planning. For the project preparation stage, it has successfully adopted remote sensing for topographic survey/mapping, radar-based subsurface utility mapping, auto traffic counter classifiers and digital cadastral mapping, while 3D modelling is currently under implementation. For the construction stage, it is planning to use advanced construction technologies and materials as well as supervisory control and data acquisition systems and geographic information system-based land asset management. The authority has also launched a project monitoring information system mobile application to facilitate close, in-house monitoring of its projects on mobile phones. Besides, NHAI has planned the setting up of an integrated command and control centre for CCTV surveillance and monitoring of vehicular congestion on national highways (NH).
Alternative materials being used for road construction
With an increase in activity in the road sector, the demand for construction materials has also increased. Traditionally, soil, stone aggregates, sand, bitumen, cement, etc., have been used for road construction. However, owing to the exhaustible nature of natural resources, the environmental damage being caused, concerns regarding the increasing generation of construction waste, the Ministry of Road Transport and Highways (MoRTH) has developed certain specifications and standards to allow the use of alternative materials for road construction. Like other countries, India too is experimenting with the use of waste materials in road construction. Among these materials, fly ash and plastic waste have generated the maximum interest.
Fly ash
More than 170 million tonnes of fly ash is generated annually, of which about 40 per cent remains unutilised. The use of fly ash is being increasingly promoted in the road sector, where it is mostly used for the construction of roads, embankments and flyovers. It is also used by the cement industry as a pozzolanic material for manufacturing cement. The Ministry of Environment, Forest and Climate Change has issued several notifications for fly ash utilisation. As per the guidelines, it is mandatory to use fly ash in the construction of roads and flyover embankments within a radius of 300 km from a thermal power plant.
Plastic waste
Of the municipal waste produced, plastic waste accounts for a significant portion. The country produces about 15,000 tonnes of plastic waste daily, of which about 60 per cent is recycled and the remaining 40 per cent is either burnt (causing air pollution) or ends up in landfills and water bodies. The unrecycled plastic waste can be used for road construction. The various advantages offered by plastic waste are higher resistance to deformation and water induced damages, increased durability, improved stability and strength, etc. The projects in which plastic waste has been used involved construction of a 200 metre stretch of the Hosur-Krishnagiri six-laning project (NH-7), a 360 metre section of the four-laning project on NH-45 (near Tindivanam) and a 10.8 km section of the four-laning project on NH-45 (near Ulundurpet).
Geosynthetics
Geosynthetics are extensively used in the construction of roads and highways. They are of particular use in undertaking construction in difficult terrains such as marshy stretches and soft deposits. Geotextiles, geogrids and geocomposites provide a sustainable option for pavement stabilisation. Besides, geomembranes are used as an impermeable barrier in waterlogged areas. Along with reducing the thickness of the load-bearing layer, geogrids provide additional reinforcement which increases the life span of the road. Its usage leads to cost savings, better performance and a lower carbon footprint.
Other materials
In August 2018, the MoRTH mandated the use of bitumen and modified bitumen in the construction of flexible pavements. In addition, for ensuring homogeneity, the ministry mandated that bitumen or modified bitumen will be procured only from refineries. Meanwhile, in light of the various advantages of the ultra-high performance fibre reinforced concrete (UHPFRC) technology, the MoRTH has allowed the technology to be used to construct a bridge at 42.05 km (Sole river) on the Latur-Nilanga-Aurad stretch of NH-752 on a pilot basis. Besides improving durability, UHPFRC helps in enhancing the service life and performance of the structure.
In a nutshell
The engineering and construction market is the biggest consumer of raw materials and other resources, using about 50 per cent of the global steel production and more than 3 billion tonnes of raw materials. Any improvement in productivity by way of using alternative materials resulting in cost reductions and successful adoption of modern innovative processes will have a major impact.
In sum, technological interventions will help in creating a common data environment for enabling smooth flow of information. This data can be utilised to ensure that projects are implemented in the most cost-effective and time-efficient manner. In addition, given the various benefits offered by waste materials for road construction and the need to reduce the waste generated by construction activities, alternative materials can go a long way in supporting road construction.