Potential measurement to determine the chloride threshold concentration that initiates corrosion of reinforcing steel bar in slag concretes

被引:45
作者
Garcia, Vincent [1 ]
Francois, Raoul [1 ]
Carcasses, Myriam [1 ]
Gegout, Philippe [2 ]
机构
[1] Univ Toulouse, UPS, INSA, LMDC, Toulouse, France
[2] Bouygues Travaux Publ, Pole Ingn Mat, Paris, France
关键词
Chloride threshold; Slag cement; Portland cement; Corrosion; Steel potential; BLAST-FURNACE SLAG; GGBS CONCRETE; MILD-STEEL; FLY-ASH; CEMENT; PERFORMANCE; BEHAVIOR; BINDING; RESISTANCE; LEVEL;
D O I
10.1617/s11527-013-0130-5
中图分类号
TU [建筑科学];
学科分类号
0813 ;
摘要
The chloride content at which reinforcement corrosion occurs (Ccrit) is an important parameter for the determination of the service life of a concrete structure. Many studies have been conducted on Portland cement concrete but few data are available concerning slag concrete. In this study, a method for determining the Ccrit value is proposed. It uses capillary suction and a diffusion phase with steel-potential monitoring during the progressive contamination of the concrete by chloride. The same experimental process, capillary suction then diffusion, was performed simultaneously with tap water and chloride solution to verify the specific behaviour of specimens due to the presence of chloride. During the phase of diffusion and potential monitoring, samples were kept immersed in saturated conditions. The criterion for detecting corrosion initiation was a variation of about -250 mV (Ghods et al., Corrosion Science 52:1649-1659, 2010), which corresponds to the difference usually noted between steel in the passive and active state. Two concrete compositions were investigated: one with only Portland cement as the binder and one incorporating slag with a substitution level of 60 %. As expected, in the Portland cement concrete, a drop in potential occurred when corrosion started. For slag concrete, no potential drop was recorded because the initial potential of the steel before the introduction of chlorides was lower. The method for determining Ccrit, based on the fall in potential recorded when corrosion started, would not be suitable to compare the different compositions of binder in saturated conditions. The presence of sulphides in the pore water solution of the slag concrete is a possible explanation of this result. Tests in a solution with added sulphides tended to confirm this hypothesis.
引用
收藏
页码:1483 / 1499
页数:17
相关论文
共 48 条
[1]   Chloride threshold dependence of pitting potential of reinforcements [J].
Alonso, C ;
Castellote, M ;
Andrade, C .
ELECTROCHIMICA ACTA, 2002, 47 (21) :3469-3481
[2]  
Amitava R, 2009, CEMENT CONCRETE RES, V39, P659
[3]  
Ampadu KO, 2001, SPECIAL PUBLICATION, V199, P681
[4]   Critical chloride content in reinforced concrete - A review [J].
Angst, Ueli ;
Elsener, Bernhard ;
Larsen, Claus K. ;
Vennesland, Oystein .
CEMENT AND CONCRETE RESEARCH, 2009, 39 (12) :1122-1138
[5]   Chloride induced reinforcement corrosion: Electrochemical monitoring of initiation stage and chloride threshold values [J].
Angst, Ueli M. ;
Elsener, Bernhard ;
Larsen, Claus K. ;
Vennesland, Oystein .
CORROSION SCIENCE, 2011, 53 (04) :1451-1464
[6]   Chloride threshold level for corrosion of steel in concrete [J].
Ann, Ki Yong ;
Song, Ha-Won .
CORROSION SCIENCE, 2007, 49 (11) :4113-4133
[7]  
[Anonymous], 2006, 1152 ASTM C
[8]  
[Anonymous], 1982, CBE FORSKNING FO 482
[9]  
[Anonymous], 1997, METH REC MES GRAND A
[10]  
Arup H., 1983, SOC CHEM IND, P151