Abstract:
Electric Arc Furnace (EAF) Steel Slag is a by-product generated from
the steel-making process which is being used as aggregates for the road construction
wearing course.Replacement of naturally occurring aggregates with locally available
EAF steel slag as a road construction material would promote sustainability of road
construction, reduce carbon footprint and minimise the environmental impact of
the steel making industry. Since 1994, 100% of steel slag generated in Singapore
has been fully recycled into aggregates and used in the asphalt wearing course on
roads by LTA and PUB and within the ports by PSA. Climate change is one of
the greatest challenges of our time and a major threat to the livelihoods of living
creatures on earth. Greenhouse gasses generated from human activities is no doubt
the biggest contributor of climate change observed since the mid-twentieth century.
Carbon footprint is one of the most widely used tools to quantify greenhouse gases
for assessing the environmental impacts of a production activity. The amount of
carbon dioxide and other greenhouse gases associated with a given product can be
calculated and expressed asCO2 equivalent. This paper briefs the applications of steel
slag aggregate for asphalt pavement in Singapore and compares the carbon footprint
of locally produced steel slag aggregates with imported granite aggregates. The
environmental benefits of using steel slag have been assessed through the comparison
of embodiedCO2 emission values for steel slag aggregate and granite aggregate. Data
used in the calculations include electricity usage, diesel consumption, transportation
and use of explosives. The analysis reveals that carbon dioxide equivalent emissions
decreases as the use of EAF steel slag aggregates increases. The transportation of
granite aggregates into Singapore represents a significant contribution to its overall
carbon footprint. Thus, using steel slag aggregates generated locally in Singapore
would contribute a smaller carbon footprint to the asphalt wearing course making
process and reduces the disposal of non-incinerable waste to the landfill site.
