4.461: Building Technology 1
CONSTRUCTION AND MATERIALS
FALL TERM 2004
SCHOOL OF ARCHITECTURE AND PLANNING: MIT
Professor John E. Fernandez
Stadelhofen Station
Zurich
Santiago Calatrava Valls
Image courtesy of Per Waahlen, photographer, and Structurae
Concrete and Composites
concrete and composites
1. Introduction
practice
research
2. Concrete Issues
ductility
CO2 generation
durability
3. Improved Structural Materials
substitution
dematerialization
technology transfer
4. Material Selection and Evaluation (CES)
multi-objective optimization
material indices/ CES software
5. New and Emerging Materials
new concretes
composites
6. Architectural Form and Research Priorities
research development: NFRC
design
concrete and composites
1. Introduction
practice
research
2. Concrete Issues
ductility
CO2 generation
durability
3. Improved Structural Materials
substitution
dematerialization
technology transfer
4. Material Selection and Evaluation
multi-objective optimization
material indices/ CES software
5. New and Emerging Materials
new concretes
composites
6. Architectural Form
research development: NFRC
design
concrete and composites
ductility
Stress - Strain Curves Not To Scale
ela
sti
cz
on
e
full plasticity metals
Stress, σ
brittle ceramics
∆σ
∆δ
Stress, σ, P/A
partial plasticity reinforced concrete
Strain, δ
E = ∆σ/∆δ
brittle
plastic flow
viscous flow elastomer
Strain, δ, ∆L/L
Stress, σ
extensive cold drawing plastic
ductile
Strain, δ
Image by MIT OCW.
concrete and composites
ductility
Failure strain, Єf
Figure X
Єf - measure of the deformation of the
material at final fracture stress
Material
concrete, unreinforced
(compression)
concrete, reinforced
Ceramics
soda glass
Fracture and failure is unpredictable
0
0.02
0
low-alloy steel
0.02-0.03
mild steel
0.18-0.25
carbon steel
Probability function
εf
0.2-0.3
stainless steel,
austenitic
0.45-0.65
stainless steel,
ferritic
0.15-0.25
cast irons
0-0.18
iron
0.3
aluminum
0.5
copper
brasses and bronzes
natural rubber
0.55
0.01-0.7
5.0
Tensile Ductility, εf (except for certain
materials such as concrete, unreinforced)
Fracture stress (ceramic)
Images by MIT OCW.
concrete and composites
Toughness, Gf , and
Fracture toughness, Kc
measures of energy absorption potential through
resistance to crack propagation.
Gf ( toughness), Kc (fracture toughness) both material properties.
Gf = energy per unit of crack area
Various ways of measuring depending on the
material.
Therefore, search for materials that have high
resistance to cracks that are formed through
loading or other lifecycle stresses.
Sometimes toughness is also referred to as the area
under the stress-strain curve.
ductility
Silicon Nitride (Glass ceramic)
Aluminium Nitrides (Glass ceramic)
10
Alumina Fibre
Fracture Toughness (ksi.in^1/2)
Granite
Carbon Fibre
Limestone
1
Normal Density Concrete
Machineable Glass Ceramic
Ice (H2O)
0.1
Aerated Concrete
Low Density Refractory Brick
Ceramic foam (carbon)
Lightweight Concrete
0.01
1
10
100
1000
Price per density
10000
100000
1e6
concrete and composites
Ecological Issues
Concrete production contributes 8% of world’s total CO2
emissions.
Research in building materials for the developing world
is a moral obligation.
Issues
•
Poverty allevation
•
Safety
•
Health (IAQ, toxicity)
•
Resource Management
Cultural Issues
•
Form (resonance with place)
•
Process (acknowledges local skill set)
•
Material (regional resources)
CO2 generation
Carbon Steel
100
Alumina
Diamond
Tungsten - High Alloy (<89%W)
Concrete (High Performance)
Cement (Super Sulphate)
Sandstone(2.35)
10
Common Hard Brick
Granite(2.63)
Carbon Matrix Composite
Plaster of Paris
Marble(2.7)
Young's Modulus (10^6 psi)
1
Epoxy SMC (Carbon Fibre)
Low Density Refractory Brick
0.1
Concrete (Insulating Lightweight)
Medium Density Aluminium Foam (0.24-0.48)
Insulation Board, perpendicular to board
0.01
1e-3
Ultra Low Density Wood (Transverse) (0.09-0.22)
Natural Rubber (NR), unfilled
1e-4
1e-5
1
10
100
Production Energy (kcal/lb)
1000
10000
100000
concrete and composites
Concrete
Need for durable reinforcing and water impermeable
concrete matrix
Especially for freeze/thaw climates
durability
concrete and composites
1. Introduction
practice
research
2. Concrete Issues
ductility
CO2 generation
durability
3. Improved Structural Materials
substitution
dematerialization
technology transfer
4. Material Selection and Evaluation
multi-objective optimization
material indices/ CES software
5. New and Emerging Materials
new concretes
composites
6. Architectural Form
research development
design
concrete and composites
dematerialization, substitution, technology transfer
P
9
8
C
S(n)
A
B
S(r)
7
W(r)
G
R
10
10
10
W(n)
6
B
4
10
3
10
Projection
S(r)
5
10
W(n)
W(r)
P
A
S(n)
G
C
2
10
1
10
R
Year
Image by MIT OCW.
2020
2025
2000
1975
1950
1925
1900
1875
1850
1825
1800
1775
0
1750
Quantity (tons)
10
concrete and composites
dematerialization, substitution, technology transfer
Concrete
Dematerialization: a decrease in the material input per
unit service
Is occurring in certain industrial sectors but ‘ecological
rucksack’ needs to be accounted for
Substitution: substituting concrete best in situations in
which safety is at high risk of compromise
Technology transfer: best employed in situations in
which to lengthen lives of existing building stock (such
as infrastructure refurbishment using carbon/epoxy
reinforcing)
Percentage of Total (weight)
100
80
Projection
60
40
20
2020
2010
2000
1990
1980
1970
1960
1950
1940
1930
1920
1910
1900
0
Year
Image by MIT OCW.
Measurement of Percentage of Renewable Versus Nonrenewable
Materials Consumption in the US
concrete and composites
1. Introduction
practice
research
2. Concrete Issues
ductility
CO2 generation
durability
3. Improved Structural Materials
substitution
dematerialization
technology transfer
4. Material Selection and Evaluation (CES)
multi-objective optimization
material indices/ CES software
5. New and Emerging Materials
new concretes
composites
6. Architectural Form
research development
design
concrete and composites
multi-objective optimization
concrete and composites
multi-objective optimization
Carbon Steel
100
10
Young's Modulus (10^6 psi)
1
0.1
Normal Density Concrete
0.01
1e-3
1e-4
1e-5
0.1
1
10
Thermal Expansion (µstrain/°F)
100
ceramics
• Glass ceramics
Machineable, good fracture
toughness
• Very HPC (Ductal)
Ductile concrete
• Ceramic foams
Lightweight, structural material
• New laminated
glasses
Laminated glass (Dupont SGP
interlayer)
concrete and composites
new concrete
Ductile concrete
Steel whisker reinforcement
Increased toughess
Increased water impermeability (few
micropores)
60
ductile concrete
Bending strength, MPa
50
40
30
20
10
normal concrete
0
0
300
600
Displacement, microns
Image by MIT OCW.
900
1200