Structural health monitoring to self-healing roads

As infrastructure faces increasing stress from climate change and usage, advanced technologies such as structural health monitoring, self-healing materials, and predictive analytics are emerging as vital tools to ensure safety, longevity, and resilience.

For decades, India’s large-scale infrastructure sector has served as the backbone of the nation’s economic growth. From connecting places to facilitating the movement of people and goods over land or water, roads and bridges do not just provide a pathway to transportation but are the lifelines of connectivity.

However, consider a scenario where an arterial road or bridge is severely impacted by an unexpected flood, earthquake, heavy rain, or a construction fault due to the use of low-quality materials or inappropriate technology. Beyond connectivity breakdown, structural damage can be fatal to both the structure and the people using it. While issues related to construction can be addressed at the design and development stage, ensuring structural integrity on an ongoing basis is crucial. Predictive maintenance is critical not only because these assets are high-investment systems but also because they must operate safely and reliably over decades.

While technology has been a game-changer in predictive maintenance, material choices, design considerations, and construction strategies also play a significant role in creating resilient roads and bridges.

Material innovations

Several material choices have emerged recently that offer distinct advantages, including high rut resistance, durability, and resistance to low-temperature cracking. For example, stone matrix asphalt (SMA) is a type of dense, gap-graded mix asphalt pavement that can be used as a wearing course and on roads with heavy traffic. Thin white topping (TWT), similarly, is a concrete overlay that is an innovative pavement rehabilitation technique, enhancing the life of existing asphalt roads with rutting and shoving issues.

Cement-grouted bituminous mix (CGBM) is a composite material that offers improved resistance to rutting and moisture damage, as well as a smooth ride. Other advanced materials include polymer-modified bitumen (PMB), cold mix asphalt, and micro-surfacing emulsions, all of which offer enhanced durability, flexibility, resistance to water, and stability under heavy traffic. High-performance concrete (HPC), fibre-reinforced concrete, and recycled materials (RAP, plastic waste) also offer durable roads.

Concrete remains the preferred option for bridge construction. While reinforced concrete is the ideal variant for bridge construction, ultra-high-performance concrete (UHPC) is the more suitable choice for emergency bridge maintenance. Rajesh Pandit, Technical Director, Qualitech Concrete Systems, states, “UHPC aids in faster construction as it can be prefabricated and offers high strength and extended lifespan. When combined with steel beams, UHPC offers lightweight yet strong structures that can replace damaged bridge components efficiently.” “Concrete bridges can withstand harsh weather, heavy loads, and environmental stress; require minimal upkeep; and are fire-resistant,” adds Rajesh.

Design considerations

Ensuring the longevity of these large-scale infrastructures is not a single-step process. It calls for adopting best practices at all stages of the project, which includes planning, design, execution, and maintenance. “The assignment should begin with the preparation of a detailed project report (DPR), which includes thorough surveys and investigations. The scope of work should be formulated utilising the best design philosophies. The tender documents and designs should be reviewed and proofread with essential steps, such as safety audits, instilling confidence in the thoroughness of the planning process.”, opines Amol Khair, Managing Director, Aakar Abhinav Consultants.

Design aspects should also consider the use of high-performance materials, sustainable construction methods aligned with circular economy principles, and periodic maintenance schedules. Road camber, superelevation, appropriate site distances, crash barriers, pavement markings, and drainage are all important factors to consider during road construction. Similarly, spans, wind velocity, load, foundation depths, and seismic activity are key considerations for bridge construction.

Tech-driven predictive maintenance

Predictive maintenance of large-scale infrastructure is driven by leveraging real-time data and analytics to foresee potential breakdowns before they occur. While sensors and digital twin technology drive the predictive maintenance of bridges, self-healing road technology is spearheading the predictive maintenance of roads.

A comprehensive structural health monitoring system for assessing bridge health can be achieved by integrating a suite of sensors, including strain gauges, tiltmeters, accelerometers, temperature sensors, and seismometers, all connected to rugged data logging systems. Structural anomalies can be easily detected and responded to by leveraging IoT sensors and analytics. These aid in continuous real-time monitoring. Similarly, detailed visual and structural assessments of hard-to-reach areas in bridges can be achieved by using drones and robotic crawlers.

Arushi Bhalla, Managing Director of Encardio Rite Group of Companies, shares her insights on Encardio’s approach to maintaining the Anji Khad Bridge. “Encardio deployed a wide array of precision sensors across critical components such as the deck, pylon, cables, and foundations. These included vibrating wire strain gauges, load cells, temperature sensors, tiltmeters, and displacement sensors, all connected to an automated data acquisition system.”, elucidates Arushi.