sustainability of cement and concrete industries · use opm, such as natural pozzolans, coal fly...
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Center for By-Products Utilization
Sustainability of
Cement and Concrete Industries
By
Tarun R. Naik, Ph. D., P. E.
Emeritus Professor, UW-Milwaukee
Presented at Dipartimento di Scienze e Ingegneria della Materia, dell'Ambiente ed
Urbanistica (SIMAU), Facoltà di Ingegneria
Università Politecnica delle Marche (UNIVPM)
Ancona, Marche, ITALY. 1 luglio 2015
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For sustainable developments: Reduce,
Reuse, Recycle, Repair, and Restore.
Minimize use of manufactured materials.Maximize environmental benefits: resource conservation,
clean water, and clean air should be the concern of everyone.
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Basic Approach
WA$T€ is wasted if you waste it,
otherwise it is a resource. Resource is
wasted if you ignore it and do not
conserve it with holistic best practices
and reduce societal costs. Resource is
for the transformation of people
and the society.
Focus on turning brown fields into green fields – opportunities are here, now!!
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Basic Approach
Recycle. Recycle as is.
Whenever possible, recycle without
additional processing
(i. e., without adding any cost to it).
Disposal leads to GHGs.
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Solid Waste ManagementLandfills contributes to global climate change
because it releases GHGs (Water Vapor,
Methane, and CO2). “Methane (is) 20 more
powerful than CO2.” Therefore, recycling
“creates a double carbon saving.” (Financial
Times, March 1, 2009).
US-EPA declared in April 2009 that CO2 is a
danger to human health (Financial Times April
18/19, 2009).
Alternatives? Increase recycling rates, as well
as MSW to energy and composting.
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Progression to 21st Century
Solid Waste Management
Recycling, sustainable management of
resources (SMR), sustainable
infrastructures, durable construction
materials, improved air quality, global
climate change, reduced GHGs, CO2
reduction & sequestration
and carbon offsets.
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Exceeding Expectations
• Imagine . . .
I would like for everyone to close
their eyes for 5 seconds and imagine
our world without concrete.
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World Without Concrete
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Why Sustainable Concrete?
• Concrete is the backbone of all construction and development activities.
• It has portland cement as the key ingredient.
• Production of portland cement is not eco-friendly:
It consumes enormous quantities of natural resources
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Why Sustainable Concrete? (cont’d)
Cement production releases a significant amount of GHGs resulting in adverse environmental impact;
It is responsible for up to about 7% of total anthropogenic GHG emissions; and,
Each construction activity involving portland cement requires new cement as it does not have significant potential for recycling.
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Sustainable Concrete
• It should have little impact on the
environment.
• It should use industrial by-products
and other recyclable materials as
substitute for natural or
manufactured ingredients of the
concrete.
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Sustainable Concrete (cont’d)
• It should have a low inherent energy
requirement.
• It should be produced with little
waste.
• It should be highly durable.
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Durability, and, therefore,
sustainability of properly designed and
constructed concrete structures
depends primarily upon the quality of
the materials of construction and other
simple, but critical, steps.
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Concrete construction can last 100
years or more if five simple steps are
followed:
(1) materials selection;
(2) structure design;
(3) construction;
(4) quality management; and,
(5) timely evaluation,
maintenance, repair, and
restoration.
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Introduction
Sustainability is important to the well-
being of our planet, continued growth of
a society, and human development.
Concrete is one of the most widely used
construction materials in the world.
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Concrete is by far the most important
building material. Worldwide, more than
10 billion cubic yards are produced each
year (2010).
The reasons for the popularity of
concrete are well known. If properly
proportrioned and produced, concrete
has excellent mechanical and durability
properties.
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Sustainable Cement
and Concrete
Entire geographical areas are running low of limestone resource to produce cement.
Travel distance to bring limestone to produce cement, therefore, has increased.
This leads to increased GHGs.
Major island-nations and metropolitan areas are running out of sources of aggregates for making
concrete and other cement-based materials.
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• A sustainable concrete structure is one that is
constructed so that the total societal impact
during its entire life cycle, including during its
use, is minimum.
• Designing for sustainability means accounting
in the design of short- and long-term
consequences on the societal impact.
Therefore, DURABILITY is the key issue.
• Blended cements (OPC + OCM), liquid
admixtures, and powder additives are needed
to continue to improve durability.
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• Over six billion tons of non-hazardous
by-product materials are produced each year in USA (2008). (8+/- billion tons of
industrial solid waste based on 1980s figures.) At an average cost of $30 per ton, it would cost B$180 to throw it all away.
• These by-products are from agricultural sources, domestic/post-consumer sources, industrial sources, and materials processing sources.
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Infrastructures are Dependent on Durable Concrete
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Energy, Environment, and
Economy Related Issues in the
Production of Portland Cement
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Energy Related Issues
After aluminium and steel, themanufacturing of portland cementis the most energy-intensive process.
The manufacturing of one tonne ofportland cement requires about sixmillion BTU of energy (equivalentto about 500 Kg. of coal per tonne ofcement produced).
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Environmental Issues
The production of one tonne of
portland cement releases
approximately one tonne of CO2
and other greenhouse gases
(GHGs) into the atmosphere.
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Economic Issue
The cost of a new portland
cement plant is in the order of
300+ million Euros per one
million tonne of installed
capacity.
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Portland Cement (OPC)
is not environmentally very
friendly material.
As good engineers, we must
reduce its use in concrete.
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Extinct Homo Sapiens
2500 BC - 2100 AD ?
Cause of death :
Friendly fire; by excessive GHG
emissions and excessive use of
natural resources, including
cement and water.
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SOLUTIONAs good engineers, we must use more environmentally friendly other cementitious/pozzolanic materials (OCM/OPM) in concrete. ..use blended cements.
Use OPM, such as natural pozzolans, coal fly ash, g. g. b. f. slag, silica fume, rice-husk ash, wood/bio-mass ash, agricultural products ash, limestone/quarry fines (OCM), etc.
Use more application specific high-quality & durable aggregates, and organic admixtures.
Use less water.
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Concrete
is environmentally very
friendly material.
As good engineers, we
must use more of it in
construction.
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As good engineers, we
must reduce the use of
water; and, we must use
more organic, liquid,
admixtures or inorganic
powder additives, or both.
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Blended “ROMAN” Cement
• Blended cement is one of the most
common efforts to make the concrete
more sustainable and less expensive.
• It involves reducing and replacing a
portion of the portland cement clinker
with suitable industrial by-products or
other recyclable (“secondary”) materials.
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Roma Coliseum, AD 72 - 81
Arena di Verona: AD 30
Cement and Concrete Roots
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Old Concrete: cement, water, sand, and
stone.
New Concrete: PLUS Liquid
admixtures…PLUS Mineral
admixtures/additives.
Modern-day Green Concrete: PLUS
recyclable materials as a replacement
of cement, water, sand, or stone; or,
all of these materials
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Blended Cement (cont’d)
• Can be used for all concrete construction
activities.
• Reduce the use of natural or
manufactured materials, and reduce
emission of greenhouse gases, by using
recycled materials.
• The worldwide potential for GHG
reduction through blended cement is
between 5 – 20 %.
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Blended Cement (cont’d)
• More environmental friendly than
portland cement because it provides
energy and ecological savings, as well
as technical benefits such as increased
strength, improved impermeability,
increase resistance to chemical attacks,
and reduced heat of hydration.
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Volcanic Ash
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Bio-Mass/Wood Ash,
including rice husk ash
(RHA), and other
agricultural products ash
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Other Useful Materials
• Powdered glass along with other pozzolanic
materials (e.g., volcanic ash, coal ash, bio-
mass/wood ash, etc.) can be used as a partial
replacement of cement.
• Pulp and paper mill residual solids can be
used as an additive in concrete for
enhancing durability properties.
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Scanning electron micrograph of Residuals
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Residual Fiber Reinforcing a Micro-crack in
Concrete
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Gypsum-based wallboard;
limestone quarry dust;
marble and stone cutting
fines; and,
lime from water
purification plants.
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Waste Washed-water
• Waste wash-water from ready–mixedconcrete plants could be used in themanufacture of sustainable concrete withoutadverse effects on concrete properties.
• Studies have suggested waste washed-watercan be used for a partial replacement ofpotable water in concrete manufacture andfor the curing of concrete.
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Geopolymer Concrete (GPC)
• GPC is a “new” technology for
manufacturing of sustainable concrete.
• It is portland cement free concrete.
• This concrete does not require cement,
or water for curing, and utilizes by-
product materials (GGBFS and/or fly
ash, with alkalis). Therefore, it is more
eco-friendly and sustainable.
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• Eliminate waste and take life-cycle
responsibility.
• Think Energy, Ecology, Economy,
and Equity.
• Acknowledge and balance these
four-Es.
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“The issue is not environment vs.
development or ecology vs. economy; the
two can be (and must be) integrated.”
“We have the human and material
resources needed to achieve sustainable
developments, not as an abstract concept
but as concrete reality”.
Kofi Annan, U. N. Secretary-General, Johannesburg, South Africa, August 2002.
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Conclusions
Recycling not only helps in reducing disposal costs, but also helps to conserve natural resources, providing technical and economic benefits, as well as helps in reducing GHGs.
This is sustainability.
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Conclusions (Cont’d)
• A sustainable concrete should have a very
low inherent energy requirement, should be
produced with little waste and with recycled
materials, be highly durable, and have
small impact on the environment.
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Conclusions (cont’d)
• The cement industry is held responsible for
global climate change to some extent. It
contributes about 7 % of total global GHGs
emissions from fuel use and calcinations
process.
• Use of the blended cement in place of
ordinary portland cement in concrete is one
of the most common efforts to make the
concrete more sustainable.
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Sustainable/Durable Concrete
• Use less cement
• Use less water
• Use project specific durable aggregates
• Use powder additives and liquid
admixture
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RESOURCE
CONSERVATION
“The earth, the sea (water), and the air
are the concern of every nation.”
President John F. Kennedy, autumn 1963,
in a speech to the U.N. General Assembly.
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La bella terra
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The Beautiful Earth – La Bella Terra
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http://cbu-uwm.info/
<http://www4.uwm.edu/ceas/faculty_profiles/TNaik.html>
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Fourth International
Conference on Sustainable
Construction Materials &
Technologies,
Las Vegas, Nevada, USA
August 7-11, 2016
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Ringrazio molto
per il vostro
interesse.
Thank you very much
for your interest.
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Foundry By-Products
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Recycled-Concrete Used for
Aggregates
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Post-consumer Glass,
Plastics, and tires
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Recycling of Construction &
Demolition Debris in Concrete
• Recycling of C & D debris conserves:
Raw materials, Energy, Water; and,
Reduces the emission of greenhouse gases.
• Most common way of using CD debris is as
aggregates.