NTPC Simhadri develops first-of-its-kind construction aggregate using fly ash

NTPC Simhadri is the first coastal station of India’s largest energy conglomerate, NTPC. With 4×500 MW capacity, Simhadri is the first NTPC project using sea water for condenser cooling and ash disposal. Commissioned in 1997 in a record time of 39 months, the station set a new benchmark in project execution.

NTPC Simhadri has developed a first-of-its-kind Model Building using Nano Concrete Aggregate (NACA), made from fly ash. Not only has this unique innovation set a new benchmark for utilization of power industry by-products and resolved the ecological concern of ash disposal, it has further developed a viable construction alternative that uses minimum water and sand, and no stone in its composition, presenting an optimum solution for natural resource conservation.


A brainchild of the Grand Ash Challenge, Nano concrete is an innovative construction aggregate that replaces regular stone with 76% fly ash, a key derivative of thermal power generation. With this, research and development at NTPC has earmarked scope for hundred percent utilization of power industry by-products.

Resolving the poignant ecological concern of ash disposal, the aggregate is exemplary of the alternate resource development the environment needs right now.

The product is cast as stone, broken in jaw crushers through multiple phases of aggregate, making it ideal for better bonding. Attaining better compressive strength than regular construction material through hydration chemistry, no thermal energy is required for a stronger composition.

In line with the Sustainable Development Goals, its composition requires minimum usage of water and sand as compared to a regular stone aggregate. With a high specific gravity in the range of 1.8 to 1.9 gm/cc, it exhibits low porosity with water absorption. As a result, use of stone for construction and land for ash disposal is also minimized, leading to an ultimate solution for natural resource conservation.

Even at just 50% penetration into the natural stone market in India, it is critical to underscore the scope for 107 million tons of NACA, capable of consuming 81.5 million tons of generated fly ash. A highly practical construction substitute for terrains with scarce and dwindling natural resources, the innovation is capable of revolutionizing the market dynamics.

Such accurate technological applications illuminate the road ahead for conglomerates to take that major leap towards an optimistic ecological and industrial co-existence.


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