India, Institute for Solid Waste Management and Ecological Balance: Fly Ash used in higher performance and energy efficient road construction

Nellore, India - November 29, 2015
Springtime brings flooding to many parts of southern India. Roads made of tar or bitumen are commonly subjected to this flooding, especially near water causeways, as has happened recently between Nellore and Tada. In road construction, cement concrete is superior but is an expensive alternative and therefore cannot be implemented widely. Road construction companies are now experiencing an industry wide change to address this issue. Coal fly ash aggregates are being implemented to improve the quality of roads with increased maneuverability and cost efficiency.

The Institute for Solid Waste Management and Ecological Balance, among other institutes of it’s kind, widely advocate for the utilization of fly ash for road construction. Due to several of its physical and chemical properties, fly ash makes a choice material for road construction. During construction, it settles less than 1%. When properly compacted, fly ash does not exhibit any long-term settlement issues and can be compacted easily while utilizing sufficiently less water than its industry alternatives. With the use of regular construction equipment, it can be mixed with lime to spread along soil providing significant strength unmatched by its competitors.

Its hardening property is useful for road embankment/pavement construction necessary to reduce pressure on retaining walls. When used as filler, expansive properties of soil can be reduced considerably. It stabilizes well with lime and cement, facilitating its use as filler material. The high permeability factor of fly ash eases free drainage during rainfall and afterwards.

Fly ash provides a cost-effective solution, saving approximately 75% of costs. Its use in construction leads to numerous environmental benefits. Notably it helps with the disposal of fly ash, generally viewed as a waste material. And of course, it reduces fossil fuel burning that otherwise would have needed for producing more cement and other road construction materials.