A study on the microcell and macrocell of seawater-fly ash concrete columns with cold joints

• Main Authors: Go, Lance Hencer W., Lim, Patrick Jerwin G., Tan, Christine Joy S., Teng, John Robert L.
• Format: text
• Language: English
• Published: Animo Repository 2018
• Subjects: Fly ash; Cement; Building materials
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/7733
• Institution: De La Salle University

Corrosion has been a problem in the construction industry ever since steel was used in infrastructure works. This problem is especially evident in reinforced concrete, a material widely used in infrastructure projects for its strength and economical effectiveness. The overarching goal of this paper is sustainability in the construction industry. Through recycling fly ash, a byproduct of the combustion process that occurs in coal fired power plants and utilizing seawater, an extremely abundant and easily accessible material especially along the coast, the researchers hope to ease the stress placed on the environment with the use of traditional construction methods. This study explored the effects of the partial replacement of cement with the fly ash and the feasibility of employing sea water in the mixing and curing processes with regards to the corrosion of reinforcing steel bars in concrete. Fly ash was used to partially replace cement at different percentages (0%, 15%, and 30%) and freshwater and seawater were utilized in both the mixing and curing of the concrete column samples. The corrosion level were measured at 7th, 14th, 21st, and 28th day curing using microcell and macrocell tests. These tests are nondestructive and had no lasting effect on the samples. In addition to these tests, the impressed current technique was employed to accelerate the corrosion process and simulate the long term effects. The concrete columns contained segmented reinforcing bars in order to allow the measurement of corrosion at different points of the column. To validate that these samples still reach the minimum design strength, cylinder samples were produced from the same design mix used for the columns and tested with strain gauges attached. This study will reveal whether or not the substitution of fly ash and sea water will prove to be viable in terms of controlling the extent of corrosion that is produced compared with the traditional concrete and freshwater. Initial findings concluded that seawater alone is not enough to sup