1. Life-cycle Assessment-Based Selection of Low Environmental Impact Mixes for Breakwater Structural elements
Maristela G. da SILVA, Marcella SAADE, Vanessa GOMES
Department of Civil Engineering, Federal University of Espírito Santo,

2. Introduction
Clinker Portland = major contributor to the environmental impact of typical concrete mixes - alternative, low impact clinker substitutes
GHG perspective can bring misleading results. LCA considers potential environmental impacts from raw material extraction to end of life activities and provides a broad environmental picture.

3. LCA not feasible at time Consolidation: screening tool
Introduction
Research began in 2002, aiming to evaluate and select a chemical activator for gbfs use in breakwater structures; evaluate physical and mechanical properties, durability and potential marine impacts related to the material selected
LCA not feasible at time
Consolidation: screening tool
Research concerning the studied concrete elements began in 2002, aiming to evaluate and select a chemical activator for ground blast furnace slag (bfs) use in breakwater structures and, at the same time, evaluate physical and mechanical properties, durability and potential marine impacts related to the material selected for such application.
LCA of the investigated concrete mixes was not feasible in Brazil at the time of the original study, and laboratory and field tests were performed for all mixes considered. Consolidation of the technique since its standardization now enables life cycle assessment use as a screening tool to provide environmental information on different concrete mixes´ impact up to manufacturing to (ANIMAÇÃO 1) discard unsuitable, high impact concrete mixes prior to performing any further laboratory or in-situ simulation tests of breakwater structures, to reduce research time and costs.

4. Methodological approach
Breakwater structures’ design characteristics, compliance with bending and twisting internal tensions, and manufacturing constraints = the structure’s geometry

5. Methodological approach
Stability coef. 13
2300 kg/m3
10+ material reduction

6. Methodological approach
66% ggbfs
96% and 1,65: vitrif. and refractive index
REF: 1:2.25:2.25:0.45, (CP III-32 RS: gravel 1: gravel 2: water)

7. Methodological approach
100x200mm; 7, 28 and 365 days in wet chamber: physical and mechanical properties
10 blocks: marine environment (1y) - taxonomic level anal. and systematic ordering.
Extra block: seawater lab tank (1y)
Water pH measured weekly

8. Methodological approach
Life Cycle Assessment
Cradle-to-gate
Avoided burden approach
1MPa
“Subtracting the environmental loads - that cease to exist due to recycling of the coproduct - from the production process that generates the last.”

9. Methodological approach
Material
Source
Blast furnace slag (bfs)
Local steelmaking industry reports
CP III-32 cement
Silva, 2006
Gypsum
Raw material database from SimaPro 7.3
Lime, hydrated, loose, at plant
Ecoinvent v.2.2
Tap water, at user
Sodium silicate, hydrothermal liquor, 48% in H2O, at plant
Gravel, crushed, at mine (Granite)
Environ-mental indicators
EE ren – MJ.MPA-1
EE nren – MJ.MPA-1
GWP – kg CO2e.MPA-1
AP – kg SO2e.MPA-1
EP – kg SO2e.MPA-1
POCP – kg C2H4e.MPA-1
ODP – kg CFC-11e.MPA-1
bWF – m3.MPA-1
NRC – kg.MPA-1

10. Compressive strength at 28 days (MPa)
Results
Physical and mechanical assessment
Mix
Compressive strength at 28 days (MPa)
REF
52.0 A
36.1 B
25.1 C
24.8 D3
22.1 D4
48.4 D5
49.7 E
16.0

11. Results Life Cycle Assessment Indicator Standard mixes A B C D3 D4 D5A B C D3 D4 D5 E
REF AP
0.30*10-07
5.58*10-07
6.76*10-07
36.4*10-07
23.3*10-07
26.2*10-07
2.56*10-07
2.84*10-07 EP
1.00*10-08
8.91*10-08
10.7*10-08
175*10-08
114*10-08
129*10-08
4.74*10-08
8.14*10-08
POCP
0.07*10-07
1.09*10-07
1.32*10-07
3.00*10-07
1.82*10-07
2.01*10-07
0.51*10-07
0.18*10-07
ODP
0.11*10-11
4.26*10-11
5.19*10-11
12.3*10-11
7.50*10-11
8.30*10-11
1.81*10-11
0.54*10-11
EE ren
4.50*10-4
7.32*10-4
8.17*10-4
70.00*10-4
44.80*10-4
50.50*10-4
8.37*10-4
5.67*10-4
EE nren
0.20*10-3
3.54*10-3
4.29*10-3
16.9*10-3
10.70*10-3
11.9*10-3
1.64*10-3
0.81*10-3
EGWP
6.09*10-4
10.30*10-4
12.50*10-4
15.30*10-4
9.14*10-4
10.10*10-4
2.85*10-4
6.19*10-4
bWF
1.07*10-4
1.55*10-4
1.57*10-4
2.66*10-4
1.38*10-4
1.43*10-4
2.52*10-4
0.39*10-4
NRc
2.06*10-3
2.52*10-3
3.07*10-3
3.79*10-3
2.34*10-3
2.61*10-3
1.38*10-3
17.1*10-3

12. Results
below 40MPa
above 40MPa

13. Conclusions
Fresh discussion: updated environmental impact outlook integration to the concrete mixes selection process
Low non renewable content & GWP – physical, mechanical and environmental properties
Sodium silicate substantially increased impacts in all of the remaining categories analyzed
LCA
Save time and resources -holistic development of sustainable and durable materials
Mix D4 – best match concrete properties, regulations and GWP/NRc

14. THANK YOU! Maristela G. da SILVA, Marcella SAADE, Vanessa GOMES
Department of Civil Engineering, Federal University of Espírito Santo,