Influence of cold joints on the corrosion of steel in concrete mixed with seawater under varying water-cement ratios

• Main Authors: Caderao, Jomer Joseph, Fernandez, Raphael Allan, Santos, Zer Ivan, Toreja, Juan Philippe
• Format: text
• Language: English
• Published: Animo Repository 2016
• Subjects: Joints (Engineering); Steel > Corrosion > Testing; Concrete > Curing
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/8086
• Institution: De La Salle University

In the field of construction, there are several factors that affect concrete casting. Unanticipated delays in concrete casting produce cold joints. Cold joints are construction elements that have been proven to give detrimental effects on the overall strength on a concrete structure and allow moisture to seep, thus reaching the reinforced steel. This study aimed to evaluate the effects of cold joints on the corrosion of steel in concrete mixed and cured with seawater with the incorporation of varying water-cement ratios. A macrocell current density test was done to measure the corrosion rate of steel inside every rectangular specimen having 100x100x200mm dimensions. Three bars, measuring 60mm in length each were contained in every rectangular specimen. All the steel bars had copper wires soldered at each end, which would be connected to the potentiostat. Tests for corrosion rate were done once a week, in a period of eight weeks. Results showed a direct relationship between the water to cement ratios of the concrete and the corrosion rate. Aside from the varying water to cement ratios, the study showed that seawater increases the corrosion rate when used as curing medium. Cold joints also increased the corrosion rate. The results of the T-test showed that seawater cannot be substituted as a mixing agent for reinforced concrete due to a high significance difference value. Finally, the study concluded that the use of 0.3 water to cement ratio is the best specimen in terms of compressive strength and corrosion resistance.