Sustainable Concrete Construction in the 21st Century: Challenges

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Sustainable Concrete Construction in the 21st
Century Challenges Opportunities

• Dr. Mohamed Lachemi, P.Eng.
• Department of Civil Engineering
• Ryerson University

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Outline

• Introduction
• Current Situation
• Challenges
• Opportunities
• Research Activities

Canada Research Chair in Sustainable Construction
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Construction Industry Today
In Canada, the construction industry generates
annually 110 billions and creates almost 1
million jobs. Worldwide, this sector generates
around US3.5 trillion.
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Construction Industry Today

• Issues facing the industry
• Little emphasis on RD
• Poor image
• Mobile workforce
• Poor productivity.

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What is Sustainable Development?
"Sustainable development meets the needs of the
present without compromising the ability of
future generations to meet their own needs."
United Nations World Commission on Environment
and Development
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Sustainability Construction

• Sustainable development in construction should
  translate into
• Improved quality of life
• Protection of the environment
• Energy conservation
• Waste reduction recycling
• Efficient use of natural resources
• Better operational performance.

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Concrete in our lives
Concrete is the most widely used construction
material in the world. Worldwide, the yearly
production of concrete is of the order of 13
billion tonnes. Humankind consumes only water in
larger quantities.
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Concrete in our lives
Concrete (concretus) is the key material for
Mankind to create the built environment
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Concrete in our lives
What would modern civilization be without
concrete?
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What is Concrete?
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Properties of Concrete
Concrete is relatively inexpensive, strong,
versatile, and resistant to fire, impact, water,
and weather. It has also a longer service life
than most construction products and requires
little maintenance.
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How Good is Good Enough?
Concrete can be made to last as long as we want
it to.
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How Good is Good Enough?
Concrete can be made to last as long as we want
it to.
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How Good is Good Enough?
Concrete can be made to last as long as we want
it to.
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How Good is Good Enough?
Why do Modern reinforced concrete structures
begin to deteriorate in 20 years or less?
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The Problem
Because we use so much concrete, and because
concrete has competing materials for many
applications, the tendency is to provide the
concrete at the lowest possible cost.
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The Current Situation
In the US, it will cost US2 to US3 trillion
over the next 20 years to repair all the concrete
structures which are now deteriorating from
corrosion and are poorly made and maintained.
National Research Council Report, 1990.
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The Current Situation
In Canada, it is estimated that the cost of
repair all concrete structures is in the range of
75 billion.
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New Perspectives
High-performance and durability should be given
high priority in the selection of materials and
construction practices.
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High Performance Durability
The Confederation Bridge Expected life cycle
100 years The ice shields are exposed to salt
water, freezing and thawing and ice abrasion.
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Is the Confederation Bridge Safe?
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Another Challenge
We need to learn how to better realize the
potential of concrete as construction material by
producing it with the use of less energy and
smaller emissions of greenhouse gases.
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CO2 Gases Energy Consumption
The production of one ton of cement releases
about one ton of CO2 into the atmosphere. This
contributes to what is now commonly called global
warming.
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Cement Production
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Life Cycle Analysis
Emissions Energy
Natural Resources
SCM Additives
Water and Aggregates
Cement Production
Resource extraction
Life Cycle
Recycling
Lime Pit
Use of waste materials
Re-use
Demolition
Classifying
Landfill
Design
Adapted from Lambros Androus
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Opportunities
The construction industry is by far the most
promising sink for recycling industrial, mining,
and household wastes because of the large volume
of materials used and its tolerance for
variability in their properties.
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Vision
This Canada Research Chair in Sustainable
Construction is driven by a vision that large
volumes of waste products can be transformed into
useful construction materials, providing economic
gains, health benefits, and environmental relief.
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Waste By-product Materials

• Slag
• Fly ash
• Silica fume
• Cement kiln dust
• Industrial sludges
• Limestone screening quarry dust
• Incinerator ash.

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Fly Ash in the Construction Industry
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Fly Ash in the construction Industry
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Coal-Ash Production Utilization
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New Generation of Products

• High performance concrete (HPC)
• Self consolidating concrete (SCC)
• Reactive powder concrete (RPC)
• Flowable fill
• Structural fill
• Roller compacted concrete (RCC).

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Our Focus
Self Compacting/Consolidating Concrete (SCC) is
among the new materials that can be used for some
of our pressing needs for high performance and
more durable materials, and innovative
construction methods in the 21st century.
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New Generation of Concrete
The problem of the durability of concrete
structures due, among other things, to a
significant reduction in the number of skilled
workers in Japan's construction industry has led
to the development of SCC in the beginning of
1990s.
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What is SCC?

• SCC must
• Have a fluidity that allows self-consolidation
  without vibration,
• Remain homogeneous during and after the placing
  process, and
• Flow easily through reinforcement.

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How to Achieve Self-Consolidation?

• Limiting the coarse aggregate content
• Increasing the paste content
• Using a superplasticizer and lowering the
  water-to-powder ratio (W/P).

Okamura and Ouchi, RILEM Symposium on SCC,
Stockholm 1999
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Benefits of SCC

• Substantial reduction in construction time and
  labour cost
• Substantial reduction in the exposure to
  compaction and vibration noise
• Proper filling of restricted access areas and
  heavily reinforced members
• Facilitating constructibility with superior
  surface quality and finishing.

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Benefits of SCC (Our Approach)

• Optimization of cement use
• Safe disposal of waste products
• Increased life-span of structures
• Reduction in Greenhouse Gas Emissions.

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Use of SCC
SCC has already been used in several countries.
In Japan, major construction projects included
the use of SCC in the late 90s. Today, in Japan,
efforts are being made to free SCC of the
special concrete label and integrate it into
day-to-day concrete industry production.
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Use of SCC in Japan
The Akashi-Kaikyo Bridge the worlds longest
suspension bridge
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Use of SCC in Japan
The use of SCC shortened the anchorage
construction period by 20, from 2.5 to 2 years.
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Use of SCC in Japan
Osaka Gas Terminal the Worlds Largest PC LNG
Storage Tanks
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Use of SCC in Japan

• In addition to enlarging the capacity of the new
  tanks, the use of SCC technology resulted in
• A decrease in the number of concrete workers from
  150 to 50 and
• A decrease of construction time from 22 to 18
  months.

Osaka Gas Terminal
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Use of SCC in Japan
Osaka Gas has conducted a number of studies over
the years that eventually led to the development
of a safe and reliable world-record capacity
180,000-m3 PC LNG storage tank. In addition to
the advantage of the scale brought about by
increasing the tank capacity, construction costs
were significantly reduced by more than 10 by
aggressively introducing various new technologies
that reduced construction cost and period. In
terms of the land use, the 180,000-m3 PC LNG
storage tank can be installed in the same space
used for a 75,000-m3 double-walled metal tank,
which is an improvement in land use efficiency of
2.5 times.
Osaka Gas Co. Website
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Our Research Activities
Novel concrete mix design
Environmental other benefits
Material characterization
Sensors NDE (actual structures)
Structural performance models
Structural evaluation
Smart monitoring testing
Lab studies
Long-term behaviour durability models
Durability evaluation
Field studies
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Will SCC Become the Standard for Designing
Concrete Structures?

• One cannot design and work with a material
  which one does not know and understand
  thoroughly. Therefore, design quality starts
  with education.

Prof. Jorg Schlaich
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Our Mission
Our mission is to educate the future leaders of
the profession and to provide skills and
foundations for life-long learning and growth.
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Attracting the Best and Brightest
Research Associates and PDFs Dr. K.M.A.
Hossain, Dr. H. Kada (Faculty, France), Dr. H.
Mesbah (Faculty, France), Dr. H. Farhat
(Lecturer, Amer. Uni. Beirut) PhD Students R.
Elimov (ExxonMobil), M. Benzerzour Masters
Students B. Lambros, R. Patel, C.
Anagnostopoulos, M. Ramcharitar, G. Walters, M.
Itashi, S.A. Kashif, P. MacAteer (Yolles), M.
Lemieux (St-Lawrence Cement) Undergraduate
Students L. Wagner, S. Sutherland, A. Hassen, W.
Thaha, B. Majok
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Team of Truly Outstanding HQP
History would have it that the chiefs win the
battles when, in actually, the braves do the
fighting.
Paraphrase of an American Indian saying
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Why Sustainable development?
We do not inherit the earth (environment) from
our parents, we borrow it from our
children. Lets honor our debt!
Old African saying
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Thank you