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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.

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sustainable concrete construction in the 21 st century challenges opportunities

Sustainable Concrete Construction in the 21st Century: Challenges & Opportunities

Dr. Mohamed Lachemi, P.Eng.

Department of Civil Engineering

Ryerson University

slide2

Outline

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

Canada Research Chair in Sustainable Construction

slide3

Construction Industry Today

In Canada, the construction industry generates annually $110 billions and creates almost 1 million jobs.

Worldwide, this sector generates around US$3.5 trillion.

slide4

Construction Industry Today

Issues facing the industry:

  • Little emphasis on R&D;
  • Poor image;
  • Mobile workforce;
  • Poor productivity.
slide5

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

slide6

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.
slide7

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.

slide8

Concrete in our lives

Concrete (concretus) is the key material for Mankind to create the built environment

slide9

Concrete in our lives

What would modern civilization be without concrete?

slide10

Cement

Water

(Additives)

Aggregate

Concrete

What is Concrete?

slide11

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.

slide12

How Good is Good Enough?

Concrete can be made to last as long as we want it to.

slide13

How Good is Good Enough?

Concrete can be made to last as long as we want it to.

slide14

How Good is Good Enough?

Concrete can be made to last as long as we want it to.

slide15

How Good is Good Enough?

Why do Modern reinforced concrete structures begin to deteriorate in 20 years or less?

slide16

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.

slide17

The Current Situation

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.

slide18

The Current Situation

In Canada, it is estimated that the cost of repair all concrete structures is in the range of $75 billion.

slide19

New Perspectives

High-performance and durability should be given high priority in the selection of materials and construction practices.

slide20

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.

slide23

PEI Girder

Eiffel Tower

7800 t

7200 t

slide25

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.

slide26

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.

slide28

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

Classifying

Demolition

Landfill

Design

Adapted from Lambros & Androus

slide29

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.

slide30

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.

slide31

Waste & By-product Materials

  • Slag;
  • Fly ash;
  • Silica fume;
  • Cement kiln dust;
  • Industrial sludges;
  • Limestone screening & quarry dust;
  • Incinerator ash.
slide35

New Generation of Products

  • High performance concrete (HPC);
  • Self consolidating concrete (SCC);
  • Reactive powder concrete (RPC);
  • Flowable fill;
  • Structural fill;
  • Roller compacted concrete (RCC).
slide36

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.

slide37

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.

slide38

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.
slide39

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

slide40

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.
slide41

Benefits of SCC (Our Approach)

  • Optimization of cement use;
  • Safe disposal of waste products;
  • Increased life-span of structures;
  • Reduction in Greenhouse Gas Emissions.
slide42

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.

slide43

Use of SCC in Japan

The Akashi-Kaikyo Bridge:

the world’s longest suspension bridge

slide44

Use of SCC in Japan

The use of SCC shortened the anchorage construction period by 20%, from 2.5 to 2 years.

slide45

Use of SCC in Japan

Osaka Gas Terminal:

the World’s Largest PC LNG Storage Tanks

slide46

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

slide47

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

slide48

Our Research Activities

Novel concrete mix design

Material characterization

Environmental & other benefits

Sensors & NDE

(actual structures)

Structural performance models

Structural evaluation

Smart monitoring & testing

Lab studies

Long-term behaviour & durability models

Durability evaluation

Field studies

will scc become the standard for designing concrete structures
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

slide50

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.

slide51

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

slide52

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

slide53

Why Sustainable development?

“We do not inherit the earth (environment) from our parents, we borrow it from our children.”

Let’s honor our debt!

Old African saying