January/February 2023 - 94

Cement manufacturers are doing
their part for the clinker and cement
links of the value chain by using
decarbonated or precalcined raw
materials, such as fly ash and slag, as
much as possible to decrease the
carbon footprint of each ton of cement
produced. They are also making
efficiency improvements to plant
equipment and processes. In fact, since
1990 the cement industry has improved
energy efficiency by 20%. Additionally,
manufacturers are formulating cement
products to reduce the clinker fraction,
the most energy- and CO2-intensive
component, while still maintaining
optimum performance.
Any concrete surface exposed to the
Embodied CO2 and embodied energy of common materials
Cement is the central ingredient in
concrete, and there is more concrete
produced than any other building
material in the world. Cement is also
the most carbon-intensive material in
concrete, but it only comprises from
7-15% of a total concrete mixture. The
remainder of a concrete mixture is
typically comprised of 60-75% coarse
and fine aggregates, 14-21% water, and
up to 8% air. This proportioning means
that concrete has a lower embodied
CO2 and embodied energy relative to all
other common materials, including
some alternative foundation materials
such as timber and steel.
The cement and concrete industry
recognizes the importance of lowering
its carbon footprint. Due to the vast
amounts of concrete produced worldwide,
even small improvements to
reduce concrete's carbon footprint will
have significant impacts. Since the
1970s, improvements to U.S. cement
manufacturing have resulted in a more
than 40% decrease in production
energy. More must be done to reduce
CO2 emissions, and the industry
recognizes that collaboration with
stakeholders across the entire cement
and concrete value chain, including
94 * DEEP FOUNDATIONS * JAN/FEB 2023
those associated with the design and
construction of foundations, will be
critical to affect meaningful change in
reducing environmental impacts.
Roadmap to Carbon Neutrality
by 2050
To help with the reduction of carbon
emissions and address global climate
chang e , t he Po r t l and Cemen t
Association (PCA) has developed a
Roadmap to Carbon Neutrality. The
roadmap spells out realistic and
achievable targets in each area of
cement manufacturing, concrete
construction and project service life
aimed at progressively reducing and
ultimately reaching carbon neutrality
across the cement and concrete value
chain by 2050. Carbon neutrality
occurs when the CO2 emissions from
the production of concrete are offset by
at least an equal amount of CO2
reductions. Referred to as the " Five Cs "
for clinker, cement, concrete, construction
and carbonation, optimizing
each of these links will require the
concerted effort of government, private
organizations, contractors, academia
and the general public to help industry
reach its goals.
air provides an opportunity for
carbonation, or the absorption and
permanent sequestration of CO2 from
the air around it. Since the majority of
geotechnical structures, especially
foundations, are located underground
or underwater, the carbonation link of
the value chain is of lesser significance.
The links of the value chain representing
concrete and construction are
of particular interest to civil and
geotechnical engineers as this is the
area where they can have the greatest
impact. To create sustainable infrastructure,
project teams including
owners, architects, engineers and
contractors must have a wholistic
perspective of the project's carbon
footprint over the full lifespan of the
structure. As the cement and concrete
value chain illustrates, these considerations
point toward the need for
life cycle assessment (LCA) as an
The cement and concrete industry value chain
January/February 2023

Table of Contents for the Digital Edition of January/February 2023
