Corrosion of reinforcing bars embedded in alkali-activated slag concrete subjected to chloride attack

Abstract

Steel bar embedded in an alkali-activated slag (AAS) concrete was tested under complete immersion, in 3.5% NaCl solution by weight of the slag. Ordinary Portland cement (OPC) was also tested for comparative purposes and exposed to the same solution. Monitoring of open-circuit potential, polarization resistance measurement and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion behavior of steel bar. The corrosion resistances of AAS and OPC concretes were performed at 0, 3, 6, 9 and 12 months. Electrochemical measurements shows that AAS concrete presents passive corrosion behavior the first 3 months, after this period of time, it presents corrosion resistance decreased due to the chlorides presence at the steel/AAS interface. For 0 months immersion (28 days of curing) the AAS and OPC concretes presented a 10% of corrosion probability. After 3 months of immersion the tested AAS and OPC concretes showed similar behavior, the active potentials in the range from −0.2 to −0.6 V vs. Cu/CuSO 4, indicate a 90% probability of corrosion.

Durability of mortar and concrete containing alkali-activated binder with pozzolans: A review

“…Electrochemical measurements indicated 10% corrosion possibility for both AAS and OPC concrete before immersing the specimens. On the other hand, the authors [34] illustrated 90% corrosion probability after 3-month immersion period in which active potential was ranging from À0.2 V to À0.6 V. They [34] concluded that due to the presence of chloride in the interface of steel and AAS, these phenomena occurred.…”

“…Miranda et al [22] Corrosion resistance NaOH and Na 2 SiO 3 FA Palacios and Puertas [23] Carbonation NaOH and Na 2 SiO 3 GBFS Fernandez-Jimenez et al [24] Acid attack and sulphate resistance NaOH and Na 2 SiO 3 FA Al-Otaibi [25] Chloride penetration resistance, porosity, carbonation Ca(OH) 2 and Na 2 SiO 3 GBFS Thokchom et al [26] Acid attack NaOH and Na 2 SiO 3 FA Wallah [27] Drying shrinkage NaOH and Na 2 SiO 3 FA Bernal et al [28] Carbonation and sorptivity NaOH and Na 2 SiO 3 GBFS and MK Allahverdi et al [29] Drying shrinkage NaOH and Na 2 SiO 3 GBFS Wongpa et al [30] Water permeability NaOH and Na 2 SiO 3 RHA and FA Yang et al [31] Shrinkage strain Ca(OH) 2 and Na 2 SiO 3 GBFS El-Sayed et al [7] Sulphate resistance NaOH and Na 2 SiO 3 GBFS Kushal and Partha [32] Porosity, water absorption and sorptivity NaOH and Na 2 SiO 3 FA Al Bakri et al [33] Acid resistance NaOH and Na 2 SiO 3 FA Chaparro et al [34] Corrosion resistance NaOH and Na 2 SiO 3 GBFS Beemamol et al [35] Chloride permeability and shrinkage NaOH FA Bernal et al [36] Carbonation NaOH and Na 2 SiO 3 GBFS and FA Prabu et al [37] Acid resistance, sulphate attack and chloride penetration NaOH, KOH, K 2 SiO 3 and Na 2 SiO 3 RHA and FA Shaikh [38] Chloride penetration, sorptivity and corrosion resistance NaOH and Na 2 SiO 3 FA Karim et al [39] Porosity, water absorption and thermal resistance NaOH GBFS, POFA and RHA FA: fly ash; GBFS: granulated blast furnace slag; MK: metakaolin; RHA: rice husk ash; POFA: palm oil fuel ash.…”

“…They [33] stated that the FA based activated concrete provided a superior durability in incursive environment in comparison with OPC concrete. In the same year, Chaparro et al [34] embedded steel bar in AAS concrete specimens that were immersed in 3.5% NaCl solution. Electrochemical measurements indicated 10% corrosion possibility for both AAS and OPC concrete before immersing the specimens.…”

“…Chaparro et al [34] used embedded steel bar in an AAS concrete and immersed the specimens in 3.5% NaCl solution. OPC specimens were also tested by immersing in the same solution for comparison purposes.…”

“…11. E corr vs. time of steel bars studded in both ordinary Portland cement (OPC) concrete and alkali-activated slag (AAS) concrete[34].Fig. 12.…”