Inhibition Effect of Tartrate Ions on the Localized Corrosion of Steel in Pore Solution at Different Chloride Concentrations

Abstract

The aim of this work is the evaluation of the inhibition effect of tartrate ions with respect to the localized corrosion of steel reinforcements in alkaline solution as a function of the concentration of chlorides ions. Weight loss tests and electrochemical tests were carried out in saturated Ca(OH)2 solution with NaOH at pH 12.7 and 13.2. The results only evidence a slight inhibition effect at pH 12.7, whereas at pH 13.2 the pitting onset is inhibited also for chloride concentration up to 3 M. Tartaric acid is a dicarboxylic acid with nucleophile substituents, which can act as a chelating agent both adsorbing on the surface of the passive film and forming a soluble complex with ferrous and ferric ions. Tartrate causes an increase in the passive current density but it prevents the depassivation of carbon steel due to the action of chlorides, thus preventing pitting initiation due to the competitive adsorption on metal surface.

Durability of Mortars Manufactured with Low-Carbon Binders Exposed to Calcium Chloride-Based De-Icing Salts

“…Finally, the CSA clinker was used to produce a traditional OPC-CSA-CŜ ternary mixture (PC-CSA) and two low carbon quaternary mortars (S-CSA and FA-CSA) containing calcium sulphoaluminate clinker, calcium sulphate, supplementary cementitious materials (plain fly ash or ground granulated blast-furnace slag) and hydrated lime [25,30]. In these mixtures, proper setting time and workability were ensured by means of a tartaric acid-based admixture at 0.8 wt.% by binder mass [31]. Experimental methods Mortars were mixed by adding the cementitious powder, sand, water and admixtures in an automatic mixer with a planetary motion with the following procedure:…”

The Improvement of Durability of Reinforced Concretes for Sustainable Structures: A Review on Different Approaches

“…Corrosion inhibitors can be used to both prevent and stop chloride induced corrosion and as a remedial for structures exposed to carbonation. They can be divided in two groups: admixed inhibitors (mass inhibitors), directly added as a constituent to fresh concrete, and as preventive techniques; migrating inhibitors, applied on the concrete surface which can penetrate into the hardened cement matrix, usually adopted in rehabilitation [40][41][42][43][44]. Among the mass inhibitors, inorganic ones were firstly studied since the 1950s and efficient commercial products are available.…”

Corrosion performance of steel rebars by application of electroless Ni-P-W coating: An optimization approach using grey relational analysis

“…A considerable financial loss may take place and lead to high cost of repair. Steel rebar corrosion in concrete is a rather complex phenomenon and affected by its working environment and guided by complex electrochemical reactions [3,4]. Chloride ion penetration and nation causes severe degradation of concrete structures in marine environment [5,6].…”

“…But as the chloride concentration increases beyond a certain threshold value, this passivity is lost [9][10][11]. Furthermore, interaction with atmospheric CO 2 also decreases the pH [3]. In marine environment, coastal structures, bridges, etc., due to a high accumulation of chloride ions, severe degradation of steel rebars embedded in concrete takes place [12].…”

“…In marine environment, coastal structures, bridges, etc., due to a high accumulation of chloride ions, severe degradation of steel rebars embedded in concrete takes place [12]. The localized attack of chlorides causes rapid reduction in cross-section and failure of the structure [3]. Also, environment mediated embrittlement of microstructure of rebars may take place along with pitting causing structural steels to crack under stress [13].…”