Abstract
Concrete made with sea sand and seawater is rich in chlorine ions which are the main factors that induce corrosion of the reinforcement. In this study, an innovative method to rehabilitate reinforcement is presented; the concentrations of chloride ions and the corrosion inhibitor in concrete were measured. Electrochemical chloride extraction (ECE) was applied as a control experiment via using saturated Ca(OH)2 solution as an external electrolyte. Bidirectional electromigration (BIEM)technology combined with the corrosion inhibitor could not only remove the chloride ions but also protect the steel bar in concrete, and animidazoline inhibitor mixed in concrete is more effective than thetriethylenetetramine inhibitor due to the specific molecular structure. It was found that the optimum ratio of N/Cl reached the maximum value 3.3, when the concentration of inhibitor was 1. Meanwhile, the experimental results also revealed that the corrosion inhibitor and chloride ion concentrations reached necessary levels on the surface of the steel, and the corrosion inhibitor migrated effectively. Overall, the contents of imidazoline and triethylenetetramine inhibitor in seawater concrete are0.75% and 1%, respectively. The results demonstrate that the addition of the corrosion inhibitor and the application of bidirectional electromigration would effectively improve the durability of reinforced concrete containing sea sand and seawater.
Highlights
The last decade has witnessed an increasing demand forsand in the construction sector
Asindicated indicated in corrosion potentials of the steel bars inbars the concrete specimens
An amount of imidazoline and triethylenetetramine inhibitor were mixed into the concrete specimens which contained sea sand and seawater, and bidirectional electromigration (BIEM) technology was used
Summary
The last decade has witnessed an increasing demand forsand in the construction sector. There exists a short fall of river sand supplies, which has triggered a search for alternative sand resources. One possible alternative is desalinated sea sand, which, compared to river sand, offers several advantages: it has a lower mud content, harder particles and better gradation. Sea sand was first used in Great Britain in concrete structures [1,2]. It accounted for 12.2% of fine aggregates used in Japanese concrete in 2011; more than 90% of coastal projects used sea sand in concrete [3]. The Netherlands has utilized a large amount of sea sand in non-stressed structural components [4]
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