PSI - Issue 55

5

Poliana Bellei et al. / Procedia Structural Integrity 55 (2024) 96–102 Poliana Bellei et al. / Structural Integrity Procedia 00 (2019) 000 – 000

100

[Oyster Shell] Calcination process

8,64E+00

[Oyster Shell] Milling to powder process

4,77E-01

[Hidraulic Lime]

2,55E-01

[Oyster Shell] Milling to aggregate process

5,37E-02

[Sand]

1,19E-02

[Oyster Shell] Transport from Culatra Island (boat)

2,34E-04

Components and processess of LCA

[Oyster Shell] Transport to production facilities (truck)

9,15E-04

0,00E+00 2,00E+00 4,00E+00 6,00E+00 8,00E+00 1,00E+01

GWP per kg

Fig. 2. Components and processes of LCA in GWP per kilograms

2,00E+00

1,79E+00

1,60E+00

1,20E+00

GWP (kg CO 2 eq/m²)

8,95E-01

8,00E-01

4,00E-01

2,71E-01

2,21E-01

0,00E+00

24% NHL-OSP

24% NHL-COSP

30% S-OSA

CONTROL

Mortars

Fig. 3. Total GWP (kgCO 2 eq/m 2 ) of mortars. CONTROL: control mortar; 24% NHL-OSP: 24% of the hydraulic lime is replaced with oyster shell powder; 24% NHL-COSP: 24% of the hydraulic lime is substituted with calcined oyster shell powder; and 30% S-OSA: 30% of the sand is replacing by an oyster shell aggregate. Differences in the material acquisition processes can be observed in Fig. 2. The grinding process of oyster shells to achieve sand-sized distribution has a lower environmental impact compared to the environmental impact caused by powder grinding. Calcination of the oyster shell has been shown to be the process with the highest carbon emissions. Oyster shell powder, obtained by mechanical process, has a lower environmental impact, approximately 22% less when compared to calcined oyster shell powder (mechanical and thermal process) and closer to the control mortar. As observed, calcination is the process with the highest GWP per kilograms. Consequently, in Fig. 3 the 24% NHL COSP mortar solution exhibited the highest carbon footprint per square meter when compared to the 24% NHL-OSP and 30% S-OSA mortar. In this case, it would make sense to assess the short-term and long-term cost/benefit of producing a mortar using calcined oyster shell, and whether it truly outperforms other solutions. This would determine