seacon: redefining sustainable...
TRANSCRIPT
SEACON:Redefining Sustainable
Concrete
UNIVERSITY OF MIAMI
COLLEGE of ENGINEERING
Morteza Khatib
Francisco De Caso
Antonio Nanni
Outline
• Motivation
• Background
• Critical Issues
• Goal
• Objectives
• Consortium
• Work Packages (WPs)
• Work Package 2
• Conclusions
• Acknowledgements
UNIVERSITY OF MIAMI
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Motivation
UNIVERSITY OF MIAMI
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Flooding at home.
Have we had enough?
Background
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On October 1, 2015, a consortium of six partners and
three collaborators led by the University of Miami
started a 2.5-year research project
This project titled “Sustainable concrete using
seawater, salt-contaminated aggregates, and non-
corrosive reinforcement” or SEACON was funded
under the aegis of the European research program
called Infravation
(http://www.infravation.net/)
Background
UNIVERSITY OF MIAMI
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SEACON: Sustainable concrete using seawater, salt-contaminated aggregate and non-corrosive reinforcement (http://seacon.um-sml.com/)
Critical Issues
• More than half of the world’s population will lack sufficient
drinking water by 2025
• The construction industry uses several billion tons of
freshwater annually to wash aggregates and mix/cure
concrete
• The potential use of recycled raw materials (fuels,
aggregates, SCMs) in cement and concrete production is
limited by the chloride content• The use of seawater and
salt- contaminated
aggregates is prohibited by
standards and codes due to
associated risks of corrosion
of steel reinforcement
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http://www.water.ca.gov
Goal
SEACON’s aim is to advance the position of the concrete industry as a whole by making its product more economical, more durable and more environmentally-benign. This is accomplished by addressing the following two challenges:
a) resource and energy efficiency in road construction and maintenance (Eco-design); and
b) virgin material reduction by substitution or recycling
This goals translates in the safe utilization of seawater and salt-contaminated aggregates (natural or recycled) for a sustainable concrete production when combined with non-corrosive reinforcement
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Objectives
• Make it clear that chlorides are harmful to
“black” carbon steel reinforcement, but
do not damage the concrete’s
characteristics (i.e., workability, strength
development, durability)
• Assess through LCA and LCC durability performance and economical impact resulting from use of chloride contaminated aggregates, high chloride content cement and seawater in structural concrete
• Validate suitable reinforcement alternatives (i.e., improved SSR and GFRP)
• Demonstrate technology by means of two real-size field prototypes in two countries (Italy and Florida, USA)
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Consortium
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Partners• University of Miami (UM)
• ATP srl (ATP)
• Politecnico di Milano (POLIMI)
• Owens Corning (OC)
• Buzzi Unicem (BUZZI)
• Acciaierie Valbruna (AV)
Collaborators• Florida DOT (FDOT)
• Pavimental (PV)
• Titan America (TT)
Work Packages (WPs)
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Work Package 2 (WP2)
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Production and characterization at the lab scale of
concrete developed in WP 1 containing GFRP bars
(made of boron-free ECR glass fibers embedded in a
vinyl ester resin)
Output: evaluation of expected life of GFRP bars
embedded in chloride contaminated concrete and
recommendation for demo projects
Experimental Plan (Phase I)
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• Phase I aims at evaluating the durability of SEACON and embedded
GFRP bars in different exposure conditions (Selicato and Moro 2015).
• Concrete specimens from three different mixes:
i. Mix A: a benchmark regular concrete mix
ii. Mix B: proportions identical to mix A, except for the substitution of tap
water with seawater from Key Biscayne Bay (Florida)
iii. Mix C: contains seawater from Key Biscayne Bay and the natural-
coarse-aggregates is substituted with RCA
Mixture UnitsPhase I
mix A mix B mix CPortland cement (type II) per ASTM C 150
kg/m3
297 297 297
Fly ash (class F) per ASTM C 618 77 77 77Tap water 161 - -Seawater - 161 161Silica Sand 813 813 813NA - Coarse aggregate #57 927 927 -RCA - - 963Water reducer (BASF GL 7500)
mL/m3
731 731 731Set retarding (BASF 961r) 2071 2071 2071Air-entraining (BASF AE 90) 19 19 19Water-binder (w/b) ratio - 0.43 0.43 0.43
Fresh Concrete Characterization
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0
5
10
15
20
25
mix A mix B mix C
Slu
mp
(cm
)
0.0%
0.5%
1.0%
1.5%
2.0%
2.5%
mix A mix B mix C
Air
co
nte
nt
Concrete Durability Results
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0
10
20
30
40
50
60
70
0 28 56 84 112 140 168 196 224 252 280 308 336 364 392
Co
mp
ress
ive
Stre
ngt
h (
Mp
a)
Age (days)
Compressive Strength
Mix A
Mix B
Mix C
Outdoor
Seawater
Tidal zone
0
1
2
3
4
5
6
7
0 28 56 84 112 140 168 196 224 252 280 308 336 364 392
Ten
sile
Str
engt
h (
Mp
a)
Age (days)
Tensile Strength
Mix A
Mix B
Mix C
Outdoor
Seawater
Tidal zone
GFRP Durability Results
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• Tensile strength of extracted GFRP bars(ASTM D7205)
MixtureOutdoor Tidal Zone
Peak Stress (ksi) CoV (%) Peak Stress (ksi) CoV (%)
Mix A 131.77 0.7 124.94 3.2
Mix B 130.98 3.9 127.86 4.7
Guaranteed tensile strength of #3 GFRP bars = 120 ksi
Experimental Plan (Phase II)
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• The aim of the SEACON phase II:
i. compare laboratory accelerated aging with actual field conditions
ii. confirm the durability of the GFRP bars embedded in SEACON and
exposed to the accelerated aging
• Based on previous work (Phase I), Mix A (conventional) and B
(Seawater) were selected for future work. The mix proportions were
modified in order to be in compliance with FDOT’s requirements for
the real-size demonstration project at the Halls River Bridge (WP4)
Mixture UnitsPhase II
mix A’ mix B’Portland cement I-II (MH) low alkali
kg/m3
332 332Fly ash (class F) per ASTM C 618 83 83Tap water 168 -Seawater - 168Silica Sand 612 612NA - Coarse aggregate #57 1038 1038RCA - -Water reducer (BASF GL 7500)
mL/m3
- -Set retarding (BASF 961r) 814 814Air-entraining (BASF AE 90) 8 8Water-binder (w/b) ratio - 0.40 0.40
Fresh Concrete Characterization
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Mixture
type
Slump DensityAir
Content
(%)
Concrete
temperature
in. mm lb/ft3 kg/m3 °F °C
Mix A 4 100 146.8 2349.9 1.3 80 26
Mix B 3.75 95 147.2 2358.6 1 80 26
0
10
20
30
40
50
60
70
0 3 6 9 12 15 18 21 24 27 30
Co
mp
ress
ive
Stre
ngt
h (
Mp
a)
Age (days)
Mix A
Mix B
0
1
2
3
4
5
0 3 6 9 12 15 18 21 24 27 30
Ten
sile
Str
engt
h (
Mp
a)
Age (days)
Mix A
Mix B
SEACON Durability
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• 96 cylinders (100x200 mm) cast to obtain compressive
and tensile splitting strength at 0.5, 1, 1.5, and 2 years of
exposure to standard and accelerated conditioning
(seawater at 60° C)
• 8 cylinders cast to study chloride diffusion using SEM and
mXRF at 0.5, 1, 1.5, and 2 years of exposure to
accelerated conditioning
• Microstructural analysis using SEM every 6 months
• ASR test per RILEM recommended test method : AAR-4.1
• Sulfate attack using cement paste cubes method
(Monteiro et al. 2000)
• Shrinkage per ASTM C157
GFRP Durability
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• 48 cubes (200 mm) cast and exposed to standard ambient and
accelerated conditioning to study the GFRP bond to concrete
properties after 0.5, 1, 1.5, and 2 years per ACI440.3R, B.3
• GFRP bars were embedded in concrete beams with cross section
replicating the test blocks from bulkhead cap of Halls River Bridge
(WP4). Each specimen was reinforced with four #5 GFRP bars which
will be extracted from the concrete at 6 months, 1, 1.5, and 2 years of
exposure to accelerated conditioning and tested for:
I. Tensile properties
II. Transverse and horizontal shear strength
III. Fiber content
IV. Moisture absorption
• SEM will be used to evaluate potential degradation at GFRP
microstructure and GFRP-concrete interface
Summary
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Specimen type (in mm)
(100 mm = 3.94 in.)
MixTotal
A B
150x190x1420 mm beam with #5 GFRP bars 4 4 8
200 mm cubes with #3 GFRP bars 24 24 48
100x200 mm cylinders 70 70 140
Total 98 98 196
Conclusions
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• The possibility of using seawater in place of freshwater and recycled concrete aggregate in substitution of natural aggregate will be investigated
• At this time, it is possible to state that mechanical behavior of concrete produced with seawater from Key Biscayne Bay and recycled aggregate with the selected proportions of components can be considered comparable to the one obtained with freshwater
• No degradation for extracted GFRP bars after one year exposure to different aging conditions
• Durability of SEACON and embedded GFRP bars will be evaluated by being exposed to accelerated conditioning
• The real-size demonstration will allow us to correlate the results of the laboratory accelerated conditioning to the actual field conditions
Acknowledgments
• Infravation program under grant agreement No.
31109806.005-SEACON
• contributions of the personnel at the Pennsuco Plant of Titan
Cement Group for the advice, cooperation and permission to
use their facilities
• National Science Foundation (NSF) for the support provided to
the Industry/University Center for Integration of Composites
into Infrastructure (CICI) at the University of Miami under grant
NSF IIP-1439543
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Thank !
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COLLEGE of ENGINEERING
Questions?
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