Durability assessment of LC<sup>3</sup>-based reinforced concrete under combined chloride-sulfate environment via the EIS technique: Fid-Bau Portal

Durability assessment of LC³-based reinforced concrete under combined chloride-sulfate environment via the EIS technique

Ejbouh, Aadil / Ech-chebab, Adil / Hassi, Sara / Galai, M. / Benqlilou, H. / Ebn Touhami, Mohamed

Abstract

Highlights • The NTD EIS technique is used to assess the durability of LC³ binder against combined chloride sulfate penetration. • LC³ technology improves the durability performance of reinforced concrete structures in simulated real-life conditions chloride-sulfate penetration. • LC³ achieved the same compressive strength as traditional OPC. • The excellent resistance of LC³ against the combined chloride-sulfate attack is attributed to the CH consumption, matrix densification, and the filler effect generated by the ternary reaction of ternary LC3 binder.

Abstract Concrete technology has significantly advanced towards alternative sustainable and eco-friendly cement-based materials. Accordingly, the durability of real-life blended concrete under realistic exposure aggressive conditions needs to be explored in depth. This study evaluates the effect of local raw clay on the durability performance of underground reinforced concrete in a simulated real-life aggressive environment with combined chloride-sulfate attack. Blended limestone cement (LC) containing calcined clay (LC³) or fly ash (LCF) with 40% replacement by cement mass, were prepared concurrently to compare the results with the traditional OPC. Assessment of durability performance of reinforced blended concrete was performed using non-destructive electrochemical impedance spectroscopy technique (EIS), and compressive strength. Characterization and elaboration of electrochemical phases were monitored by X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), and SEM/EDS analysis. Electrochemical measurements showed that the diameter of the impedance semi-circle in both high and low-frequency regions of LC³-based reinforced concrete increases as corrosion progresses, while that of LCF and OPC decreases. LC³ showed the best corrosion resistance marked by a lower corrosion rate and comparable strength. Furthermore, LC³ binder exhibited a good hydration degree, with higher CH and Friedel’s salt content. Ultimately, the LC³ technology improves the durability performance of reinforced concrete structures in simulated real-life conditions which could advance its application on the industrial scale.