Abstract
In this work, the ZnAl-NO2 LDH (layered double hydroxide) is investigated as a possible additive for mitigating the chloride-induced corrosion of steel in reinforced concrete. The investigation focused on the stability and chloride binding capacity of this LDH in the pH range typical of cementitious materials. Until pH = 12.5 the material was stable and effective in capturing chloride ions from the surrounding aqueous environment. For higher pH, precisely that of hydrated cement, the LDH was partially dissolved and OH− preferentially entrapped instead of Cl−. These results suggested that ZnAl-NO2 has excellent chloride entrapping capability at neutral pH, but this is reduced with increasing pH. However, when the LDH was incorporated into mortars, the chloride ingress was delayed, signifying that the dissolution of LDH leads to a secondary mechanism responsible for chloride capture.
Highlights
The corrosion of steel in reinforced concrete affects infrastructures worldwide [1,2,3].The cost of early repair and the reconstruction of these structures can lead to severe economic losses [4]
Concrete is a porous material [5], and aggressive species like chloride ions can pass through the concrete cover, until reaching the steel reinforcement, where they disrupt the steel native passive layer and initiate corrosion [6,7]
Innovative techniques are required to slow down the chloride ingress in concrete, delay the corrosion process and extend the service life of reinforced concrete infrastructures
Summary
The corrosion of steel in reinforced concrete affects infrastructures worldwide [1,2,3].The cost of early repair and the reconstruction of these structures can lead to severe economic losses [4]. Concrete is a porous material [5], and aggressive species like chloride ions can pass through the concrete cover, until reaching the steel reinforcement, where they disrupt the steel native passive layer and initiate corrosion [6,7]. Innovative techniques are required to slow down the chloride ingress in concrete, delay the corrosion process and extend the service life of reinforced concrete infrastructures. Layered double hydroxides (LDHs) are a new class of concrete additives which can entrap aggressive anions from the environment and release selected anions (e.g., corrosion inhibitor) from their galleries. Potential applications include sequestration of chloride and carbonate ions in aggressive environments, which in turn can potentially prolong the service life of structures susceptible to corrosion. LDHs have gained attention in the recent years, due to their ion exchange properties, in concrete technology [8] and in various branches of science and engineering [9], as a de-icing additive for asphalt roads [10], catalysis, [11], pharmaceutical applications [12], photochemistry [13], electrochemistry [14,15], biochemistry [16] and more
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
