Effect of Limestone Powder Content on Chloride Threshold for Rebar Depassivation in Concrete
LI Chenzhi1, JIANG Linhua2,*
1 College of Civil Engineering, Tongji University, Shanghai 200092, China 2 College of Mechanics and Materials, Hohai University, Nanjing 210098, China
Abstract: The effect of limestone powder (LP) content on the chloride threshold for rebar depassivation was investigated. Wetting-drying cycles were conducted to accelerate the chloride penetration into concrete specimens. Half-cell potential and AC impedance techniques were employed to monitor the dynamic changes of self-corrosion potential (Ecorr) and corrosion current density (icorr), respectively, which were used to diagnose the corrosion condition of the rebar. The results indicate that the chloride threshold decreases as the LP content increases, which is attributed to the lower pH value of concrete pore solution due to decreased cement content. XRD patterns demonstrate that incorporating LP inhibits the formation of monosulfate (AFm) phase, thereby undermining the chloride binding capacity of the hydrates. The variation of icorr with time follows a three-parameter Weibull distribution, with the probability density representing the rate of passivity breakdown, which is found to increase with increasing limestone content.
1 Shi C J, Wang D H, Jia H F, et al. Journal of the Chinese Ceramic Society, 2017, 45(11), 1582 (in Chinese). 史才军, 王德辉, 贾煌飞, 等. 硅酸盐学报, 2017, 45(11), 1582. 2 Da B, Yu H F, Ma H Y, et al. Materials Reports, 2019, 33(12), 2002 (in Chinese). 达波, 余红发, 麻海燕, 等. 材料导报, 2019, 33(12), 2002. 3 Xiong Y Z, Wan H W. Concrete, 2010(9), 89 (in Chinese). 熊远柱, 万慧文. 混凝土, 2010(9), 89. 4 Xiao J, Wang Y H, Deng D H, et al. Journal of Building Materials, 2008(2), 212 (in Chinese). 肖佳, 王永和, 邓德华, 等. 建筑材料学报, 2008(2), 212. 5 Wang D H, Shi C J, Jia H F, et al. Journal of Fuzhou University (Natural Science Edition), 2018, 46(6), 874(in Chinese). 王德辉, 史才军, 贾煌飞, 等. 福州大学学报(自然科学版), 2018, 46(6), 874. 6 Panesar D K, Zhang R X. Construction and Building Materials, 2020, 251, 118866. 7 Yu B, Huang J M, Wan W W, et al. Materials Reports, 2020, 34(S2), 1227 (in Chinese). 余波, 黄俊铭, 万伟伟, 等. 材料导报, 2020, 34(S2), 1227. 8 Shi J J, Ming J, Sun W. Cement and Concrete Composites, 2018, 92, 110. 9 ASTM, C876-91, Standard Test Method for Half-cell Potentials of Uncoated Reinforcing Steel in Concrete, 1991. 10 Hu J Y, Zhang S S, Chen E, et al. Construction and Building Materials, 2022, 325, 126718. 11 Angst U M, Elsener B, Larsen C K, et al. Corrosion Science, 2011, 53, 1451. 12 Xu J X, Jiang L H, Wang J X. Construction and Building Materials, 2009, 23, 1902. 13 Meira G R, Andrade C, Vilar E O, et al. Construction and Building Materials, 2014, 55, 289. 14 Hu X, Shi C J, Li Q L, et al. Journal of the Chinese Ceramic Society, 2015, 43(4), 376 (in Chinese). 胡翔, 史才军, 李庆玲, 等. 硅酸盐学报, 2015, 43(4), 376. 15 Weibull W. Journal of Applied Mechanics, 1951, 18, 293. 16 Strzelecki P. International Journal of Fatigue, 2020, 145, 106080. 17 Li X, Grace J R, Bi X, et al. Fuel, 2016, 184, 211. 18 Jiang H P, Jiang A N, Yang X R. Rock and Soil Mechanics, 2021, 42(7), 1894 (in Chinese). 蒋浩鹏, 姜谙男, 杨秀荣. 岩土力学, 2021, 42(7), 1894. 19 Wang D H, Shi C J, Farzadnia N, et al. Construction and Building mate-rials, 2018, 181, 659. 20 Lothenbach B, Saout G L, Gallucci E, et al. Cement and Concrete Research, 2008, 38, 848. 21 Kakali G, Tsivilis S, Aggeli E, et al. Cement and Concrete Research, 2000, 30, 1073.
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2024, Vol. 38 
