Fly Ash and Bottom Ash Based Cementless Paver Blocks for Rural Pavements of India

Cement manufacturing process uses large amount of energy and results into release of substantial quantity of carbon dioxide as well as green-house gases into the atmosphere. Therefore, there is a need to find the alternative material to replace cement (partially or fully) in the concrete construction without compromising its properties.

All power plants in India today are using coal for electricity generation which results into production of huge amount of industrial waste like fly ash, bottom ash, etc. Moreover, it has been hypothesized that the current consumption of coal in India is expected to become triple (>2100 million tonnes) by 2031-2032. As per one estimate, only half of the produced fly-ash is utilised, still leaving behind huge volumes of unused fly ash. Therefore large amount of fly ash and bottom ash is required to be dumped at the rural sites. Hence, dealing with this industrial waste is now posing a serious challenge for India.

Looking to the above scenario, the innovative idea of using Fly Ash and Bottom Ash together, was implemented in the collaborative research project on “Application of Precast Products Made using Bottom Ash and Fly Ash for Rural Pavements and other Infrastructure in India”. The said project was carried out during 2015-2018 and funded by IC-IMPACTS (Canada-India Research Centre of Excellence) in which Dr Urmil Dave, Civil Engineering Department, Nirma University was Principal Investigator from India and Dr Rishi Gupta, University of Victoria, British Columbia was Principal Investigator from Canada.

The alkali activated cementless concrete paver blocks were made up using Fly Ash, Bottom Ash & combination of aggregates. Their performance was evaluated in comparison with the commercially available paver blocks through rigorous tests. The cementless concrete paver blocks behaved far more superior in mechanical properties and durability as compared to the commercially available paver blocks.

Dr Urmil Dave, the Principle Investigator says, “Encouraging laboratory results have paved the way of using the cementless concrete paver blocks for the construction of the pavement stretch at village Jaspur, near the city of Ahmedabad. The pavement stretch which was prepared two years before has been functioning quite efficiently and also being in use today. Indeed, this is a true example of the transformation of waste material into the sustainable construction material for Civil Engineering Applications.”