Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Durability of Concrete Exposed to Seawater at Early Ages: Floating Dock Method
https://orcid.org/http://orcid.org/0000-0001-7967-2149
https://orcid.org/http://orcid.org/0000-0003-0239-996X
https://orcid.org/http://orcid.org/0000-0002-2831-7531
https://orcid.org/http://orcid.org/0000-0003-1904-7426
https://orcid.org/http://orcid.org/0000-0001-9867-7631
Caisson method for the construction of breakwater structures can produce concrete caissons measuring up to 70 m long by 36 m wide and 35 m high. These caissons are gradually immersed in seawater as they are built; thus, the set concrete is exposed to seawater at early ages, within 18 to 48 h after casting in sliding formwork. The most suitable cements in terms of their resistance to chlorides are those containing active additions that result in hydrated pastes, whose gels reduce the penetrating advance of chlorides by diffusion: cements with natural pozzolans, fly ash, and blast-furnace slag. Due to this reason and the current trend of reducing the amount of clinker in cement to decrease the CO2 footprint and increase durability, a cement with a replacement of clinker up to 65% by blast-furnace slag has been used. To study the durability of slag concrete using this construction method, the properties of concrete exposed to seawater have been tested. Specimens were exposed to artificial seawater by the ponding method at different short ages for a period of 6, 18 and 36 months. The following properties were measured and compared with unexposed specimens: compressive strength, water and oxygen permeability, pore size distribution, migration coefficient DNT492 and chloride profiles. After 6, 18 and 36 months ponding, lower chloride contents were measured on the surface of concrete for the specimens exposed to seawater after 28 days curing compared to those exposed at early ages. However, these differences significantly decrease within a small depth from the exposed surface.
Durability of Concrete Exposed to Seawater at Early Ages: Floating Dock Method
https://orcid.org/http://orcid.org/0000-0001-7967-2149
https://orcid.org/http://orcid.org/0000-0003-0239-996X
https://orcid.org/http://orcid.org/0000-0002-2831-7531
https://orcid.org/http://orcid.org/0000-0003-1904-7426
https://orcid.org/http://orcid.org/0000-0001-9867-7631
Caisson method for the construction of breakwater structures can produce concrete caissons measuring up to 70 m long by 36 m wide and 35 m high. These caissons are gradually immersed in seawater as they are built; thus, the set concrete is exposed to seawater at early ages, within 18 to 48 h after casting in sliding formwork. The most suitable cements in terms of their resistance to chlorides are those containing active additions that result in hydrated pastes, whose gels reduce the penetrating advance of chlorides by diffusion: cements with natural pozzolans, fly ash, and blast-furnace slag. Due to this reason and the current trend of reducing the amount of clinker in cement to decrease the CO2 footprint and increase durability, a cement with a replacement of clinker up to 65% by blast-furnace slag has been used. To study the durability of slag concrete using this construction method, the properties of concrete exposed to seawater have been tested. Specimens were exposed to artificial seawater by the ponding method at different short ages for a period of 6, 18 and 36 months. The following properties were measured and compared with unexposed specimens: compressive strength, water and oxygen permeability, pore size distribution, migration coefficient DNT492 and chloride profiles. After 6, 18 and 36 months ponding, lower chloride contents were measured on the surface of concrete for the specimens exposed to seawater after 28 days curing compared to those exposed at early ages. However, these differences significantly decrease within a small depth from the exposed surface.
Durability of Concrete Exposed to Seawater at Early Ages: Floating Dock Method
https://orcid.org/http://orcid.org/0000-0001-7967-2149
https://orcid.org/http://orcid.org/0000-0003-0239-996X
https://orcid.org/http://orcid.org/0000-0002-2831-7531
https://orcid.org/http://orcid.org/0000-0003-1904-7426
https://orcid.org/http://orcid.org/0000-0001-9867-7631
Caisson method for the construction of breakwater structures can produce concrete caissons measuring up to 70 m long by 36 m wide and 35 m high. These caissons are gradually immersed in seawater as they are built; thus, the set concrete is exposed to seawater at early ages, within 18 to 48 h after casting in sliding formwork. The most suitable cements in terms of their resistance to chlorides are those containing active additions that result in hydrated pastes, whose gels reduce the penetrating advance of chlorides by diffusion: cements with natural pozzolans, fly ash, and blast-furnace slag. Due to this reason and the current trend of reducing the amount of clinker in cement to decrease the CO2 footprint and increase durability, a cement with a replacement of clinker up to 65% by blast-furnace slag has been used. To study the durability of slag concrete using this construction method, the properties of concrete exposed to seawater have been tested. Specimens were exposed to artificial seawater by the ponding method at different short ages for a period of 6, 18 and 36 months. The following properties were measured and compared with unexposed specimens: compressive strength, water and oxygen permeability, pore size distribution, migration coefficient DNT492 and chloride profiles. After 6, 18 and 36 months ponding, lower chloride contents were measured on the surface of concrete for the specimens exposed to seawater after 28 days curing compared to those exposed at early ages. However, these differences significantly decrease within a small depth from the exposed surface.
Durability of Concrete Exposed to Seawater at Early Ages: Floating Dock Method
Lecture Notes in Civil Engineering
Barros, Joaquim A. O. (Herausgeber:in) / Cunha, Vítor M. C. F. (Herausgeber:in) / Sousa, Hélder S. (Herausgeber:in) / Matos, José C. (Herausgeber:in) / Sena-Cruz, José M. (Herausgeber:in) / Vera-Agullo, Jose (Autor:in) / Lample, Rosa (Autor:in) / Pina-Zapardiel, Raul (Autor:in) / Silva, Nelson (Autor:in) / Mueller, Urs (Autor:in)
FIB International Conference on Concrete Sustainability ; 2024 ; Guimarães, Portugal
4th fib International Conference on Concrete Sustainability (ICCS2024) ; Kapitel: 16 ; 122-130
09.01.2025
9 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch