Low Carbon Cement Contributing
to the Growth of Emerging Economies
construction sector in India is one of the largest emitters of CO2
in the atmosphere accounting for about 22% of the total annual emission,
with the largest contribution coming from brick and cement production.
This is due to the sheer volume of material and fuel consumption in the
production of these materials. The Indian brick sector produces around
350 billion bricks in a year emitting around 270 million tonnes of CO2
and consuming around 945 million tonnes of top soil per year. The
cement industry produced around 210 million tonnes of CO2 in
2016-2017 consuming around 325 million tonnes of limestone besides other
fuels and waste materials such as fly ash and slag. Although the brick
and cement industries are the highest emitters of carbon dioxide and
consume significant amount of resources, they are still the backbone of
the construction industry leading the pathway to the growth and
development of the country.
You cant do without bricks and cement!
In the cement sector, concrete is one of the
major forms of use. Concrete is one of the topmost contributors of
man-made CO2 emission. Projections from WBCSD-CSI shows that
cement consumption in India is going to increase to 22% by 2050 compared
to the present 8% as we move further on the path of development. This
creates two main challenges for the future:
How do our available resources meet the
How can the increased CO2
emission from the projected demand be mitigated?
Any improvement in the sustainability of
cement production can have a huge impact on resource efficiency and CO2
released into the atmosphere. Presently the three most important
approaches being practiced and researched are as follows:
Improvement of energy efficiency
Use of biofuels and other alternative
Replacement of clinker by substitute
materials or supplementary cementitious materials (SCMs)
Various other technologies are also being
looked at such as cement-less concrete (geopolymers), carbon capture and
storage. However, these are quite utopian ideas and do not have any
commercial prospects at present.
Thus, we do not have any other viable and
affordable option but to look at supplementary cementitous materials.
One of the most promising technologies in this area is the Limestone
Calcined Clay Cement. This cement uses calcined clay as a SCM (around
30%). With the addition of crushed raw limestone (around 15%), it reacts
synergistically with the calcined clay and gives a general-purpose
cement equivalent in quality to all general-purpose cements. Life cycle
analysis shows the prospects of a saving of around 30% CO2
compared to portland cement and use of around 50% mine rejects.
Thus, the Limestone Calcined Clay cement has
the potential of satisfying the needs of rapidly developing countries to
satisfy their infrastructural demand while taking care of the
environment and reducing the need of virgin resources.
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