Controlled release mechanism and inhibition performance of smart inhibitor LDH-NO2 in the reinforced concrete structures

• Published in: 工程科学学报 Vol. 44; no. 8; pp. 1368 - 1378
• Main Authors: Cheng WEN, Yu-wan TIAN, De-yue YANG, Gui WANG, Pei-chang DENG, Chao-fang DONG
• Format: Journal Article
• Language: Chinese
• Published: Science Press 01.08.2022
• Subjects: controlled release; density functional theory (dft); inhibition; inhibitor; layered double hydroxide (ldh)
• ISSN: 2095-9389
• DOI: 10.13374/j.issn2095-9389.2021.08.01.003

Reinforcement corrosion is one of the most serious problems limiting the durability of concrete structures. Corrosion inhibitors are used as admixtures in the fresh concrete to prolong the service life of the concrete structure, and calcium nitrite is the most extensively tested admixed inhibitor. However, the premature deactivation and overdose of conventional inhibitors limit their application, and one strategy to solve this problem is to use smart inhibitors with controlled release, long-term effects, and targeting performance. In this paper, a smart inhibitor of LDH-NO2 was prepared based on the Zn‒Al layered double hydroxide as a shell and the nitrite ions as a core. The first principles calculation, physical detection techniques, immersion test, and electrochemical methods were performed to study the micro- and macro-controlled release mechanism and inhibition property of LDH-NO2. The results show that: (1) The nitrites in LDH-NO2 can release spontaneously in the chloride-contaminated or/and carbonated