Journal of South China University of Technology(Natural Science Edition) ›› 2024, Vol. 52 ›› Issue (3): 28-40.doi: 10.12141/j.issn.1000-565X.230030

• Materials Science & Technology • Previous Articles     Next Articles

Study on Sodium β-glycerophosphate in Concrete Affects the Inhibited Behavior of Steel Bar

WANG Xiaoxian1 LIU Jiaping1 MU Song2 JIN Ming1 MA Qi2   

  1. 1.School of Materials Science and Engineering,Southeast University,Nanjing 211189,Jiangsu,China
    2.National Key Laboratory of High Performance Civil Engineering Materials,Jiangsu Building Science Research Institute Co. ,Ltd. ,Nanjing 210008,Jiangsu,China
  • Received:2023-01-05 Online:2024-03-25 Published:2024-03-05
  • Contact: 刘加平(1967-),男,教授、博士生导师,主要从事钢筋混凝土耐久性研究。 E-mail:liujiaping@cmjgk.cn
  • About author:王潇舷(1992-),女,博士生,主要从事钢筋混凝土耐久性研究。E-mail:xiaoxian_wang@foxmail.com
  • Supported by:

    the National Key Research and Development Project of China(2021YFF05008022021YFF0500803); the Southeast University Outstanding Doctoral Dissertation Cultivation Fund(YBPY21)

Abstract:

In the high alkaline environment of concrete, in order to improve the resistance of steel bar in concrete to chloride ion erosion, this study adopted a new environmentally friendly organic rust inhibitor-β-glycerophosphate sodium to protect the steel bar and achieve the purpose of extending the service life of reinforced concrete structures. In this study, the electrochemical measurements were used to monitor the evolution properties of the steel embedded in concrete in real time. The corresponding key parameters were obtained to explore the relationship between sodium β-glycerophosphate and steel passive film in the passivation period, as well as the relationship among sodium β-glycerophosphate, steel passive film and chloride ions during the maintenance passivation period, and then the rust resistance mechanism of this kind of organic matter was revealed. The results obtained by OCP, LPR and EIS electrochemical testing methods show that: β-sodium glycerophosphate forms a more density protective film through physicochemically interacting with Fe oxides/hydroxides on the steel surface, so as to make the surface of the steel bar form a protective film with more inhibited behavior, which also improves the resistance of the steel bar under chloride ion erosion. The resistance of the steel bar in each of the four solutions is: NaOH + 0.1 mol/L sodium β-glycerophosphate > saturated clarified Ca(OH)2 > NaOH > saturated clarified Ca(OH)2 + 0.1 mol/L sodium β-glycerophosphate. Among them, the critical chloride ion concentrations (ccrit) of steel bars in NaOH, NaOH + 0.1 mol/L sodium β-glycerophosphate and saturated clarified Ca(OH)2 solutions are: 0.02 mol/L, 0.07 mol/L, and 0.04 mol/L, respectively, while no effective passive film is generated on the steel bar in saturated clarified Ca(OH)2 + 0.1 mol/L sodium β-glycerophosphate. In addition, the addition of sodium β-glycerophosphate to Na+ solutions can promote the formation of a more dense passive film on the steel bar surface with a faster passivation rate. That is, more than 80% passivation film can be formed in 72 h, and the rust inhibitor rate is as high as 99.80%. Furthermore, further comparative analyses of the effects the Na+ and Ca2+ solutions themselves on the resistance of the steel bar under chloride ions erosion show that Ca2+ solution is more conducive to the resistance to chloride ion erosion ability, and the corrosion inhibition efficiency is more than 90%.

Key words: concrete simulation pore solution, sodium β-glycerophosphate, passive film, chloride ion, electrochemical behavior

CLC Number: