Loading in 2 Seconds...
Loading in 2 Seconds...
Sustainable Concrete Construction in the 21 st Century: Challenges & Opportunities. Dr. Mohamed Lachemi, P.Eng. Department of Civil Engineering Ryerson University. Outline. Introduction Current Situation Challenges Opportunities Research Activities.
Dr. Mohamed Lachemi, P.Eng.
Department of Civil Engineering
Canada Research Chair in Sustainable Construction
In Canada, the construction industry generates annually $110 billions and creates almost 1 million jobs.
Worldwide, this sector generates around US$3.5 trillion.
Issues facing the industry:
"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
Sustainable development in construction should translate into:
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.
Concrete (concretus) is the key material for Mankind to create the built environment
What would modern civilization be without concrete?
What is 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.
Why do Modern reinforced concrete structures begin to deteriorate in 20 years or less?
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.
In the US, it will cost US$2 to US$3 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.
In Canada, it is estimated that the cost of repair all concrete structures is in the range of $75 billion.
High-performance and durability should be given high priority in the selection of materials and construction practices.
The Confederation Bridge
Expected life cycle : 100 years
The ice shields are exposed to salt water, freezing and thawing and ice abrasion.
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.
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.
Emissions & Energy
SCM & Additives
Water and Aggregates
Use of waste materials
Adapted from Lambros & Androus
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.
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.
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.
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.
Okamura and Ouchi, RILEM Symposium on SCC, Stockholm 1999
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.
The Akashi-Kaikyo Bridge:
the world’s longest suspension bridge
The use of SCC shortened the anchorage construction period by 20%, from 2.5 to 2 years.
Osaka Gas Terminal:
the World’s Largest PC LNG Storage Tanks
Osaka Gas Terminal
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
Novel concrete mix design
Environmental & other benefits
Sensors & NDE
Structural performance models
Smart monitoring & testing
Long-term behaviour & durability models
“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
Our mission is to educate the future leaders of the profession and to provide skills and foundations for life-long learning and growth.
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)
R. Elimov (ExxonMobil), M. Benzerzour
B. Lambros, R. Patel, C. Anagnostopoulos, M. Ramcharitar, G. Walters, M. Itashi, S.A. Kashif, P. MacAteer (Yolles), M. Lemieux (St-Lawrence Cement)
L. Wagner, S. Sutherland, A. Hassen, W. Thaha, B. Majok
“History would have it that the chiefs win the battles when, in actually, the braves do the fighting.”
Paraphrase of an American Indian saying
“We do not inherit the earth (environment) from our parents, we borrow it from our children.”
Let’s honor our debt!
Old African saying