seacon: redefining sustainable...

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

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COLLEGE of ENGINEERING 2

Motivation

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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/)

http://www.infravation.net/

Background

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SEACON: Sustainable concrete using seawater, salt-contaminated aggregate and non-corrosive reinforcement (http://seacon.um-sml.com/)

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

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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Questions?

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