1. Cement Based Composites as a Solution to
Sustainable Infrastructure Materials
Barzin Mobasher
Professor
School of Sustainable Engineering and the Built Environment
Ira A. Fulton Schools of Engineering
Arizona State University
Tempe, AZ 85287-5306
Department of Civil Engineering
Pontifícia Universidade Católica do Rio de Janeiro
(PUC-Rio)
2. Sustainable Construction Products
Societal Challenges
– Challenges we face in the next several decades?
– Global warming, societal development, and energy use
Sustainability
– Reuse and recycle
– Design for durability
– Quality control, wastefulness
– Structural mechanics, new materials and design systems
Renewable Energy power generation
– Enabling Infrastructure Technologies
Composite systems- New Technological Developments
– Short fiber, continuous fiber systems, TRC
– Ductility based designs utilizing nonlinear material properties
– Aerated Concrete, life cycle energy consumption
3. Outline
Introduction
Bilinear Moment-Curvature Relationship
Moment and Curvature Distributions
Closed-Form Solutions for Load-Deflection
Algorithm
Closed-form deflection equations
Parametric Study
Normalized Distance vs. Deflection Coefficient
Normalized Distance vs. Normalized Curvature
2-D Deflection Contour
Experimental Verifications
Discussions
Ductility Durability
Economy
FRC
4. Introduction
Severe damages to cement-based
materials due to the inherent
brittleness and low tensile strength.
ECC, UHPC, HPFRC are developed
and applied
Hybrid manner -- fibers, steel rebars,
FRP rods
Flexural members -- beam, slab,
bridge girder, tunnel lining
Modelling and design approach based
on analytical equations are desired
Soranakom C., Mobasher B. , “Closed-Form Solutions for Flexural Response of Fiber-Reinforced Concrete Beams”(ASCE)0733-
9399, 2007.
5. Globalization- American Model of Economic Development
China and India have achieved fast economic growth rates by rapid industrialization
Over 40% of the 1.3 billion Chinese already live in cities with sky-rocketing demand for
energy and energy-intensive materials
China
– 50% of global cement production, followed by India and US (6% and 3%, resp.)
– 40% of global steel production, followed by Japan and US (9% and 7%, resp.)
– 15% of the global power generation. Projected to triple By 2030
– 80% of electric power generated from coal
– Equivalent of two 500-MW coal power plants built every week for the next 20 years
– China has passed the U.S. as the World’s largest emitter of CO2
6. Concrete Specified vs. Delivered
2000 4000 6000
Specified f'c, psi
2000
4000
6000
8000
10000
DeliveredStrength,psi
All concrete classes
28 day strength Each data point = 100 cubic yards
Source: ADOT Database for One ready mix
supplier over a course of two years
Over-strength
Level
7. Durability, Sustainability, Energy use
• The Carbon cycle in construction materials industry should be
viewed in the context of high initial energy demand followed by very
efficient operation. CO2 generation from Cement utilization and
vehicle fuel consumption yields erroneous results
• Durability, efficient performance, and raw materials conservation are
essential components of sustainable designs
FRC as Activation
Energy for
Sustainable Design
8. FRC Engineering Applications
Ductility, Durability
The type and volume fraction of fibers affect the
level of energy absorption
increased energy absorption, fatigue life,
impact/explosive loading conditions, and seismic
resistance
Pavements/slabs, Pre-cast components,
Shotcrete
12. Textile Reinforced Concrete
Sandwich layers
Low cost equipment set up
Uniform production
high performance fabric-cement composites
Tension, Compression, beam members
High pressure pipes
15. Homogenization of Crack spacing –Mechanical interlock
0 10 20 30 40
Crack Spacing, mm
0
0.2
0.4
0.6
0.8
1
CumulativeDistributionFunction
Zone 1
= 0.015
Zone 2
.0273
Zone 3
= 0.0387
AR-Glass Fabric
0 0.02 0.04 0.06
Strain, mm/mm
0
5
10
15
20
25
Stress,MPa
Zone 3
Zone 2
Zone 1
AR-Glass Fabric
AR Glass Bonded
Fabric
Polyethylene (PE)
Woven Fabric
Polypropylene (PP)
Knitted Fabric
16.
17. Stress-Strain for Hardening and Softening FRC
Material parameters are described as a multiple of the first cracking tensile strain
(cr) and tensile modulus (E)
Compression model Tension model
19. Specifications for Canal lining, WWF, or
rebar replacement
Fiber Reinforced Concrete Mix
Photo Courtesy: Pima-Maricopa Irrigation
Project, Sacaton, Arizona
Traditional #5 rebar layout
Photo Courtesy: Rick Shelly, Pulice
Construction
20. Fiber-reinforced shotcrete for initial
shaft sinking support
• Deep shaft (2189 m), 9 m dia, copper mine
• 400,000 tons copper per year for the next 40 years
• Three geological units
• A range of orthotropic stress conditions
• Several modes of instability: gravity driven, rockmass
shear yielding, brittle failure
• The shotcrete system must achieve a high early
strength and ductility within a short period (less than 24
hours).
21. Effect of curing age on flexural response
0 0.03 0.06 0.09 0.12 0.15
CMOD, inch
0
500
1000
1500
2000
2500
3000
Load,lbf
36 hrs - Sample 1
36 hrs - Sample 2
16 hrs - Sample 1
16 hrs - Sample 2
8 hrs - Sample 1
8 hrs - Sample 2
Three Point Bending Test Result
Mix 1
10-12 lbs/yd3 of macro fibers
22. Strain-Softening FRC
0 0.01 0.02 0.03 0.04 0.05
Deflection, in
0
200
400
600
800
1000
FlexuralLoad,lb
Experiment
Present Model
L-056 : 9.5 lb/yd3 FibraShield
sample 1
age: 14 days
0 400 800 1200 1600
Stress (psi)
-2
-1
0
1
2
SpecimenDepth,(in)
ARS Method, LE material
ASU Method, Elastic Softening
Stress Distribution
Softening Zone
L056-01
23. Comparison with JCI Method
JCI method overestimates the
residual strength of
– synthetic fibers by 1.4 times
– steel fibers by 6.3 times
Bakhshi M, Mobasher B. “Sustainable Design of Structural Concrete Materials: a Case Study of
Incorporating Materials Science, Structural Mechanics, and Statistical Process Control”, A Report (SR-
633) to Arizona Department of Transportation, Tempe, AZ, 2010.
24. FRC for 2-way elevated slab structures
Composition Amount
Cement Type I 350 kg
Fly ash 60 kg
Aggregate (1.1:1) 1800 kg
W/C < 0.5
Supper plasticizer 1.25 % by Vol.
Vf = 80 - 100 kg/m3
25. Construction and Field Testing
Cast in place SFRC
Use minimum reinforcement along the
column lines to prevent progressive
collapse
26. Modeling of Failure Mechanisms
Oberseite - ULS Mittellast
S
N
West Ost
Unterseite
S
N
WestOst
Durchgezogen: bis 200 kN
gestrichelt: bis Brucklast
27. Plastic analysis approach
Distributed load on a simply supported square
slab. The work equations are derived as:
Where the resultant NR and rotation θ (from figure
9a) are:
For the four segments with an NR acting at 1/3 of
δmax :
θ θ
q
δmax
L
L/2
L/2
m
m
A A
δ
Yield Line
Square Slab
Simply Supported
int extW W
R( N ) ( M L )
2
2 2 4
R
L L qL
N q ( ) ( )
2 max
L
2
2
4 4
4 3
max max
L
qL
( ) ( ) ( M ) ( L ) ( )
2
24
ult
p
q L
M
28. Round panel tests for
evaluation of SFRC
Test setup
– displacement controlled, continuous
support, center point load
Dimensions
– D, t= 1500, 150 mm
– stroke diameter = 150 mm
Vf = 80 kg/m3 Vf = 100 kg/m3
29. ASU- Rio Tinto Project – Magma Copper mine,
Superior , Arizona
ASU is evaluating the initial fiber-
reinforced shotcrete support
design for a 2000 m-deep shaft
at Resolution Mine, Arizona.
30. Project Overview
• Evaluate fiber-reinforced shotcrete
performance
• No rockbolts planned for initial
support.
• Deep shaft (2189 m)
• Three geological units
• A range of stress conditions
(increased with depth)
• Several modes of instability: gravity
driven, rockmass shear yielding, brittle
failure
31. 3DEC Evaluation of Shotcrete
Linear-elastic shotcrete liner installed in
low stress, blocky ground.
Early age properties use for shotcrete
and rock-shotcrete interface along full
length of model shaft.
Extreme fiber stress used to evaluate
potential shotcrete cracking.
Tensile extreme fiber stress exceeding
the tensile strength combined with
tensile thrust at a given liner section
indicates potential for a crack to form
through the liner.
Large regions of connected cracks
would indicate potential for a block
breaking through the shotcrete.
Extreme Fiber Stress
3DEC-predicted liner stresses and
potential cracking in TAL unit
Tensile extreme fiber stress exceeding
tensile strength of shotcrete
32. Use of Yield Line Analysis and Design
procedures
int extW W
2
2
P
L
M P P
4
ult
P
P L
M
35. Analysis of Precast Wall Panels
Assume continuous wall, pin connection at
the bottom and free at the top
Lateral water pressure in ultimate and
serviceability limit states
37. Analysis, Design and Installation of precast
water tank panels
Load Case1:
– Self weight + Water pressure
– Moment in short span controls
Load Case2:
– 1.4 Self weight +
1.7 Earth pressure +
1.7 Uniform pressure due to surcharge
– Moment in short span direction SM1
38. From Microstructure to full scale wall testing
-Durable, Energy efficient, Effective R-value, 3.4/in,
- Fire, Pest resistant, no autocalve
-Acoustical insulation, impact resistant Easy to use
LVDT-1
LVDT-2
Actuator
39. Precast, Cont’d (slope stabilization)
Slope stabilization
(FRC segments
are bolted into the
rock)
40. Precast, Cont’d (slope stabilization)
Slope stabilization
(FRC segments
are bolted into the
rock)
41. FRC Applications in Shotcrete
One of the widespread applications of fibers is shotcrete. Short
fibers is added to concrete and used in the form of shotcrete to
replace or reduce the steel reinforcement. Several case studies
are introduced in the following slides for applications such as:
• Tunnel lining
• Slope stabilization
• Retrofit and strengthening
Tunnel lining with light steel
mesh, ready for shotcrete
42. Shotcrete, Cont’d (tunnel lining)
Fiber-reinforced concrete can be used for shotcreting tunnel lining.
Macro steel fibers and macro synthetic fibers are typically used for
this application. Using fibers can reduce or even eliminate the steel
rebar reinforcement which results in faster and cheaper
construction. In comparison with steel mesh system, shotcreting
FRC uses lesser quantities of concrete since it follows the rock
contours and typically has less rebound. Enhanced durability is
obtained with FRC since galvanic corrosion cells are not created
with fibers.
Completed Spraying FRC
43. Shotcrete, Cont’d (slope stabilization)
Fiber-reinforced concrete can be used for shotcreting for the
purpose of slope stabilization. Macro steel fibers and macro
synthetic fibers are typically used for this application. Using fibers
can reduce or even eliminate the steel rebar reinforcement which
results in faster and cheaper construction. In comparison with steel
mesh system, shotcreting FRC uses lesser quantities of concrete
since it follows the rock contours and typically has less rebound.
Spraying FRC on slopes
45. Shotcrete retrofit
Fiber-reinforced concrete can be used for shotcreting in retrofit and
strengthening of existing structures. Macro steel fibers and macro
synthetic fibers are typically used for this application. Using
shotcrete with fibers is a fast and economic way to retrofit cracked
surfaces and to strengthen the structures for extra load or seismic
resistance.
Seismic Retrofit of Littlerock Dam, California with SFRS
46. Structural Applications
There are several more
applications for FRC in special
structures. Short fibers are
added to concrete to increase
the tensile strength and ductility
of the material in order to resist
explosive, cyclic, or corrosive
factors. Several case studies
are introduced in the following
slides for applications such as:
• Seismic applications
• Defensive applications
• Hydraulic applications
• Masonry structures
FRC cylinders
after failure
47. Seismic Design, Coupling beams
Researchers eliminated a substantial amount of reinforcing bars by using a highly
flowable, steel fiber-reinforced concrete where the fibers are introduced during the
concrete mixing process. “Instead of constructing a skyscraper in the time-
consuming and labor-intensive procedures used today, we envision this new
coupling design being fabricated off site and delivered ready for installation
53. Tunnel Lining
Fiber-reinforced concrete can be used in tunnel lining segments. Macro
steel fibers and macro synthetic fibers are mainly used for this type of
application. Using fibers can reduce or even eliminate the steel rebar
reinforcement which results in faster and cheaper production. Due to the
curved nature of lining segments, fibers are good replacement for rebars
because of their distribution in the segment.
M. Moccichino et al., 2010 world
tunnel conference, Italy
BEKAERT
56. Multiple cracking in tension and flexure
Tensile test
Flexural test
Moment-curvature
57. Modelling procedures
Tension model
Compression model
Bond (interface) model
Stress/strain distribution
Moment-curvature relationship
Normalized parameters
Incorporations of equilibrium equations
Moment and curvature distributions throughout the volume
Integration, application of boundary conditions
Data reduction and solutions for stress, strain, load, deflection
distributions
59. Derivation of Moment-Curvature Relationship
Strain Stress
Incrementally impose
0 < t < tu
Strain Distribution
Stress Distribution
SF = 0, determine k
Moment: M = SFciyci+ SFtiyti
Curvature: φ=c/kh
Simplified
bilinear moment-
curvature
Stage : l>w, b>a
60. Moment-Curvature Distributions
Use Static Equilibrium to get moment distribution
Curvature distributions along the beam are generated based on simplified bilinear
moment-curvature model
64. Experimental Verification
Three point bending tests
Six full scales FRC beams
Fiber content : 50kg/m3 and 75kg/m3
Beams H500 H1000 H1500
Height (mm) 500 1000 1500
Effective depth (mm) 440 940 1440
Total length (mm) 3000 5900 9000
Span(mm) 2640 5640 8640
Width(mm) 250 250 250
Reinforcement longitudinal bars 8-ϕ14 8-ϕ20 8-ϕ24
Geometry of specimens
Parameters for current Model
Beam Type
Fiber
Content
kg/m3
E
Simulated
E εcr η
MPa MPa μstr
H500
50 30800 30800 146 0.24
75 32100 32000 110 0.26
H1000
50 30800 29500 125 0.22
75 32100 32100 120 0.26
H1500
50 30800 29500 128 0.23
75 32100 32100 117 0.26
Minelli F., Conforti A., Cuenca E., Plizzari G., “Are steel fibres able to mitigate or eliminate size effect in shear?”, Materials & Structures ,
47:459–473, 2014
65. Experimental Verification – Comparison with
s- model
Four-point bending test
200(b) × 200(d) × 2000 (L) mm
Steel fibers: 50 kg/m3
Rebar 2-ϕ12
Dupont D. “Modelling and experimental validation of the constitutive law (σ-ε) and cracking behavior of steel fiber
reinforced concrete” Ph.D. Dissertation, Catholic University of Leuven, Belgium, 2003
P/2 P/2
900 200 900
2000
s- Model
E =29 GPa, εcr = 130 µstr
μ =0.38, βtu = 192
ω = 10, λcu = 27, γ = 0.7
Bilinear M-φ Model
E =30 GPa, εcr = 130 µstr
η=0.21, m = 4.88, q =20
EIg =4.0×1012
EIcr=8.4×1011
(s- Model) (s- Model)
(s- Model)
66. Experimental Verification – RC with Steel
fibers
Three-point bending test
Fiber content: 50 and 75 kg/m3
Beams Group #1 Group #2 Group #3
Height (mm) 500 1000 1500
Span(mm) 2640 5640 8640
Width(mm) 250 250 250
Reinforcement
Longitudinal
bars
8-ϕ14 8-ϕ20 8-ϕ24
Beam
Type
Fiber
Conten
t kg/m3
εcr, E
η m q EIg, 1013
EIcr, 1013
10-6
GPa
Group
#1
50 146 30.8 0.24 6.04 22 8.02 1.93
75 120 31 0.26 9.32 33 8.07 2.10
Group
#2
50 120 30 0.22 5.18 20 62.5 13.8
75 120 31 0.28 6.88 22 64.6 18.1
Group
#3
50 120 29 0.24 6.04 22 204 48.9
75 120 30 0.28 7.16 23 211 59.1
Simulated Parameters
Normalized curvature vs. Normalized moment Deflection at mid-span vs. Applied load
Minelli F., Conforti A., Cuenca E., Plizzari G., “Are steel fibres able to mitigate or eliminate size effect in shear?”, Materials
and Structures , 47:459–473, 2014
Group #1
67. Group #2
Group #3
Experimental Verification – RC with Steel
fibers
Minelli F., Conforti A., Cuenca E., Plizzari G., “Are steel fibres able to mitigate or eliminate size effect in shear?”, Materials
and Structures , 47:459–473, 2014
68. Experimental Verification – Textile Reinforced
Concrete
Three-point bending test
30 (b) × 9(d) × 220 (L) mm
Textile fabrics:
Polypropylene
Aramid
ID εcr,µstr E, Gpa η m q EI, 107
EIcr, 107
100P 130 22 0.01 4.28 298 4.0 0.044
100A 130 22 0.1 17 157 4.0 0.41
25A75P 130 22 0.05 10.48 198 4.0 0.202
100P
Normalized curvature vs. Normalized moment Deflection at mid-span vs. Applied load
Simulated Parameters (Avg.)
Mobasher, Barzin, et al. "Correlation of constitutive response of hybrid textile reinforced concrete from tensile and flexural
tests." Cement and Concrete Composites 53 (2014): 148-161.
69. 100A
25A75P
Mobasher, Barzin, et al. "Correlation of constitutive response of hybrid textile reinforced concrete from tensile and flexural
tests." Cement and Concrete Composites 53 (2014): 148-161.
Experimental Verification – Textile Reinforced
Concrete
70. Experimental Verification – RC with Steel
fibers
Four-point bending test
200(b) × 600(d) × 4000 (L) mm
Steel fibers
Longitudinal and shear reinforcement
Measure deflections by five LVDTs
x = 750, 1500, 2000, 2500, 3250 mm
Beam
ID
Fiber
volume
fraction
(%)
Longitudinal reinforcement
Shear
reinforcement
Ratio
Tension Top bar
Ratio
(%)
Rebars
(%)
V1 0 0.262 4φ10 2φ6.3 0.104 4φ6.3
V2 0 0.262 4φ10 2φ6.3 0 0
ID m q EIg, 1014
EIcr. 1014
V1 2.56 100 1.01 0.131
V2 1.91 92 1.01 0.071
Deflection at mid-span vs. Applied load
Simulated Parameters
Details of beams
75. Mechanics of Fiber and Textile
Reinforced Cement Composites
CRC press, 2011
E-mail: barzin@asu.edu
http://enpub.fulton.asu.edu/cement/
76. Conclusion
New technologies and directions are clearly available
in our future progression in Construction industry.
Use of materials science based and mechanics based
approaches to obtain better ways to characterize,
model, analyze, and design.
Better train, communicate, and follow through
– respect the construction component of the manufacturing
process.
Address specifications, quality, and long term
performance.
Fiber Reinforced Concrete can be effectively used as a
technology enabler for our alternative energy
generation, use and infrastructure development
