Effect of Na3PO4 addition in mortar on steel reinforcement corrosion behavior in 3% NaCl solution

Testing phosphate ions as corrosion inhibitors for construction steel in mortars

“…In a previous work [29] In agreement with previous work [32,36,37], phosphates could also combine with the Ca 2+ ions present in the pore solution, precipitate as calcium phosphate and contribute in hindering oxygen and chloride diffusion.…”

“…Besides, the adequate phosphate to chloride ratio in mortars is controversial and the inhibition mechanism is not clear. Some authors propose a dual effect, where calcium phosphate could block the pores avoiding diffusion of aggressive species while iron phosphate could block cathodic or anodic sites [31,32,36,37].…”

“…Papers published earlier by other authors, that address the effect of phosphates in mortar, are either accelerated tests [36], deal with short term exposures [26,37], use monofluorphosphates [35], or study pre-oxidized or as-received rebars [32].…”

Corrosion Inhibitors for Reinforced Concrete: A Review

“…Corrosion Inhibitors, Principles and Recent Applicationssteel with 0.5 M inhibitor solution for 72 h forms a protective layer which further enhanced the protection efficiency [38][39][40][41]. Nahali et al [42] studied the effect of Na 3 PO 4 addition in chloride-contaminated mortar and concluded that the addition of phosphate inhibitor in concrete decreases the chloride ions effect on localized corrosion.…”

“…Soluble phosphate compounds, such as disodium phosphate or mono fluoro phosphate, can be mixed with mortar or applied on concrete [42] by immersion or by surface application [45]. Song et al [46] evaluated the role of alkaline nitrites on the inhibition of corrosion of steel in binary (OPC + PPC) and ternary cement (OPC + PPC + PSC) and reported that ternary system provides 81% protection efficiency ( Table 1) for steel in concrete in the presence of 3% chloride concentration.…”