Ecological footprint and economic assessment of conventional and geopolymer concrete for sustainable construction

Cement is the binding material in conventional concrete which involves excess lime quarry and large volume of CO2 emission during its production. On the other hand, the geopolymer concrete is a cement-less concrete where materials such as fly ash, blast furnace slag, bottom ash, construction, and demolition waste etc. are utilized as binder (precursor) when activated with alkaline solution. In the present study, ecological footprint along with the mechanical properties and the incurred cost of the production of M30 conventional cement concrete prepared according to IS, ACI and DOE code of practices were assessed and compared with that of geopolymer concrete. Cement concrete prepared according to IS, ACI and DOE code of practice had the compressive strength of 41 MPa, 43 MPa and 32 MPa respectively at 28 days. The compressive strength of geopolymer concrete was found to be 48 MPa at 28 days which was higher than that of all the conventional concrete. But the ecological footprint and the cost of geopolymer concrete production was found to be lower than that of conventional concrete. The geopolymer concrete had the lowest ecological footprint or the bio-productive land requirement of 0.0224 gha/ m3 when compared to that of conventional cement concrete. The conventional cement concrete prepared as per the IS code had the highest ecological footprint of 0.0546 gha/m3. Heat curing contributed to 44% and the material contributed to 46% in the total ecological footprint of geopolymer concrete. However, burden of energy incurred on heat curing can be further reduced by the use of non-conventional source of energy. The production of geopolymer concrete also provides a sustainable disposal option for industrial waste produced as a by-product. Therefore, geopolymer concrete could be seen as eco-friendly and economical alternate to conventional concrete in the era of sustainable development.