SEACON: Redefining Sustainable Concrete

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1 SEACON: Redefining Sustainable Concrete Morteza Khatib Francisco De Caso Antonio Nanni

2 Motivation Background Critical Issues Goal Objectives Consortium Work Packages (WPs) Work Package 2 Conclusions Acknowledgements Outline 2

3 Motivation Flooding at home. Have we had enough? 3

4 Background 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 noncorrosive reinforcement or SEACON was funded under the aegis of the European research program called Infravation ( 4

5 Background SEACON: Sustainable concrete using seawater, salt-contaminated aggregate and non-corrosive reinforcement ( 5

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

6 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 6

7 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 environmentallybenign. 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 7

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

8 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) 8

9 Consortium 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) 9

10 Work Packages (WPs) 10

Work Package 2 (WP2) Production and characterization

containing GFRP bars (made of boron-free ECR glass

evaluation of expected life of GFRP bars embedded in

11 Work Package 2 (WP2) 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 11

12 Experimental Plan (Phase I) 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. iii. Mix B: proportions identical to mix A, except for the substitution of tap water with seawater from Key Biscayne Bay (Florida) Mix C: contains seawater from Key Biscayne Bay and the naturalcoarse-aggregates is substituted with RCA Mixture Units Phase I mix A mix B mix C Portland cement (type II) per ASTM C Fly ash (class F) per ASTM C Tap water Seawater kg/m Silica Sand NA - Coarse aggregate # RCA Water reducer (BASF GL 7500) Set retarding (BASF 961r) ml/m Air-entraining (BASF AE 90) Water-binder (w/b) ratio

13 Slump (cm) Air content Fresh Concrete Characterization % % % % 5 0.5% 0 mix A mix B mix C 0.0% mix A mix B mix C 13

14 Tensile Strength (Mpa) Compressive Strength (Mpa) Concrete Durability Results Compressive Strength Outdoor Seawater Tidal zone Age (days) Mix A Mix B Mix C Tensile Strength Outdoor Seawater Tidal zone Age (days) Mix A Mix B Mix C 14

15 GFRP Durability Results Tensile strength of extracted GFRP bars (ASTM D7205) Mixture Outdoor Tidal Zone Peak Stress (ksi) CoV (%) Peak Stress (ksi) CoV (%) Mix A Mix B Guaranteed tensile strength of #3 GFRP bars = 120 ksi 15

16 Experimental Plan (Phase II) 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 Units Phase II mix A mix B Portland cement I-II (MH) low alkali Fly ash (class F) per ASTM C Tap water Seawater kg/m Silica Sand NA - Coarse aggregate # RCA - - Water reducer (BASF GL 7500) - - Set retarding (BASF 961r) ml/m Air-entraining (BASF AE 90) 8 8 Water-binder (w/b) ratio

Compressive Strength (Mpa) Tensile Strength (Mpa) Fresh Concrete Characterization Mixture type Air Concrete Slump Density Content temperature in. mm lb/ft 3 kg/m 3 (%) F C Mix A 4 100 146.

17 Compressive Strength (Mpa) Tensile Strength (Mpa) Fresh Concrete Characterization Mixture type Air Concrete Slump Density Content temperature in. mm lb/ft 3 kg/m 3 (%) F C Mix A Mix B Mix A Mix B Mix A Mix B Age (days) Age (days) 17

18 SEACON Durability 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 18

19 GFRP Durability 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. III. IV. Transverse and horizontal shear strength Fiber content Moisture absorption SEM will be used to evaluate potential degradation at GFRP microstructure and GFRP-concrete interface 19

20 Summary Specimen type (in mm) Mix (100 mm = 3.94 in.) A B Total 150x190x1420 mm beam with #5 GFRP bars mm cubes with #3 GFRP bars x200 mm cylinders Total

21 Conclusions 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 21

22 Acknowledgments Infravation program under grant agreement No 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

23 Thank! Questions? seacon.um-sml.com 23

Durability of GFRP Reinforcement in Seawater Concrete. Morteza Khatibmasjedi and Antonio Nanni University of Miami

Durability of GFRP Reinforcement in Seawater Concrete Morteza Khatibmasjedi and Antonio Nanni University of Miami Outline Introduction Background Work Packages (WPs) WP2 Tasks and Objectives Durability