A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Optimization of Corrosion Countermeasures for Chloride Attacked RC Bridge Piers in a Strengthening Project
Abstract In Japan, a number of expressway structures located in the Pacific coast areas are suffering chloride attack and corrosion, caused by airborne salt and sea water. A typical case are highway bridges of the Seisyo Bypass which has been serving for 37 years. Recently, a project of seismic strengthening was implemented to about 160 piers of those bridges. Before the strengthening, inspection of the corrosion and countermeasure was necessary. Usually, the critical chloride concentration for steel corrosion was used as 1.2 kg/m3 for repair or strengthening. In this project, a careful in-situ inspection was carried out for corrosion and chloride amount of the piers. A relationship between chloride concentration and the corrosion degree was established using the inspected data. Accordingly, higher critical values of chloride concentration were suggested. Through careful inspection and prediction, the strengthening work using the values can satisfy durability requirement afterwards, and also reduce the cost. Based on the strategy, the strengthening work was carried out. Concrete cover was chipped by waterjet to some depth, which was determined by the critical chloride value. Polymer cement mortar with lithium nitrite was coated at the chipped surface against corrosion, and after that reinforced concrete jacketing was installed for strengthening.
Optimization of Corrosion Countermeasures for Chloride Attacked RC Bridge Piers in a Strengthening Project
Abstract In Japan, a number of expressway structures located in the Pacific coast areas are suffering chloride attack and corrosion, caused by airborne salt and sea water. A typical case are highway bridges of the Seisyo Bypass which has been serving for 37 years. Recently, a project of seismic strengthening was implemented to about 160 piers of those bridges. Before the strengthening, inspection of the corrosion and countermeasure was necessary. Usually, the critical chloride concentration for steel corrosion was used as 1.2 kg/m3 for repair or strengthening. In this project, a careful in-situ inspection was carried out for corrosion and chloride amount of the piers. A relationship between chloride concentration and the corrosion degree was established using the inspected data. Accordingly, higher critical values of chloride concentration were suggested. Through careful inspection and prediction, the strengthening work using the values can satisfy durability requirement afterwards, and also reduce the cost. Based on the strategy, the strengthening work was carried out. Concrete cover was chipped by waterjet to some depth, which was determined by the critical chloride value. Polymer cement mortar with lithium nitrite was coated at the chipped surface against corrosion, and after that reinforced concrete jacketing was installed for strengthening.
Optimization of Corrosion Countermeasures for Chloride Attacked RC Bridge Piers in a Strengthening Project
Sanada, Osamu (author) / Yanagisawa, Hiroshi (author)
2017-08-06
9 pages
Article/Chapter (Book)
Electronic Resource
English
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