DOI: 10.20350/digitalcsic/17382
title: Dataset for the paper “Criado, M., Torres, E., Hinojosa-Platero, J., Pachón-Montaño, A. 2025. Decontamination-Sludge-Induced Corrosion of Steel in Simulated Pore Solutions and Alkali-Activated Slag Pastes. Corrosion and Degradation Materials. 6(1), 8”

description: [EN] This is the experimental dataset used in the paper Corrosion and Degradation Material, 6: 8 (2025) (https://doi.org/10.3390/cmd6010008) in which the potential corrosion and current density of the steel sheets, simulating drums embedded in new sodium carbonate and silicate-activated slag formulations with surrogate decontamination sludges have been determined. This data set includes the results of the FTIR spectrum of the surrogate decontamination sludge, which presents the vibration bands of its main constituents such as EDTA, hydrazine and citric and oxalic acids. In addition, the results of the evolution of the corrosion potential (Ecorr) and corrosion current density (icorr) values as a function of time for carbon steel sheets submerged in simulated Portland cement and alkali-activated cements pore solutions along with the decontamination sludge have also been included, where was observed that the steel was in an active state. The results of the evolution of these two parameters and the electrochemical impedance spectroscopy for carbon steel embedded in the reference cement and sodium carbonate-activated slag and sodium silicate-activated slag pastes have been compiled in this data set and the carbon steel coupons in the reference cement showed the best corrosion resistance, followed by those embedded in the sodium silicate-activated slag. The results of the Raman spectrum of the corrosion deposits on the surface of the steel embedded in the sodium carbonate-activated slag show the presence of hematite. Finally, the results of the characterisation of the cementitious pastes mixed with the decontamination sludge by XRD and FTIR have been included, where the presence of the acidic sludge results in a decrease in pore-water pH and favours the initiation of the corrosion process in the sodium carbonate-activated slag paste.
description: Potential corrosion (Ecorr) and linear polarisation resistance (Rp) (Rp=ΔE/ΔI) were recorded for up to 37 days of immersion. Steel corrosion current density (icorr) can be calculated using the Stern–Geary equation 20, where icorr=B/Rp, applying ΔE ±20 mV at a scan rate of 0,125 mV/s and adopting a tentative value of 26 mV for the B constant for steel in the active (corroding) state 21. The piece of equipment used for the electrochemical measurements was a Gamry Interface 1010E Potentiostat/Galvanostat/ZRA controlled using Gamry Framework software. A classical three-electrode setup was used, employing the carbon steel sheets as the working electrode, Ag/AgCl (3M KCl) as the reference electrode, and a graphite bar as a counter electrode in a plastic cell filled with 200 ml of the simulated pore cement solution. Furthermore, carbon steel corrosion in the alkali-activated slag and reference pastes cubes was monitored using Ecorr, Rp, and electrochemical impedance spectroscopy (EIS) measurements for up to 14 months. EIS measurements were recorded at Ecorr with a 10mV root mean square (rms) amplitude excitation voltage, in a frequency range of 100 kHz to 10 mHz, with a logarithmic sweeping frequency of 10 points per decade. In this case, the setup consisted of a three-electrode electrochemical cell wherein the working electrode was carbon steel sheets, the reference electrode was Ag/AgCl (3M), and a stainless-steel mesh was used as a counter electrode surrounding the cementitious material specimen, acting as the electrolyte of the electrochemical cell. Raman spectra were obtained using a Renishaw Qontor Raman Microscope equipped with a 514 nm laser and a Leica microscope. The spectra were obtained with 50× magnification objective lenses. The laser power used was 25 mW, but the measurements were made at 5% of this power. The integration time was 1 s, and 20 accumulations were collected. The Raman shift was calibrated before measurements according to the silicon peak at 520.4 cm−1. The software employed for data acquisition and analysis was WIRE 5.3. XRD was conducted using a diffractometer (D8 Advance instrument, Bruker) with Cu-Kα1,2 radiation (1.5406 Å and 1.5444 Å), no monochromator, a goniometer radius of 217.5 mm, and a nickel filter. The X-ray tube was operated at 40 kV and 30 mA. The settings used were as follows: a variable 6 mm divergence slit (hydrated pastes); 2θ angle, 5–70°; step time, 0.5 seconds; and step size, 0.02°. The software used for the analysis of the XRD diffractograms was DIFRAC.EVA, using the free crystallographic database Crystallography Open Database (COD). The FTIR samples were prepared using the KBr pellet method: 1.0 mg of powder binder and 200 mg of KBr were weighed, and the mixture was homogenised in an agate mortar. Subsequently, it was compacted under vacuum in a die until a pellet was obtained. The spectrometer used was a Thermo Nicolet 6700. Spectra were obtained with 64 scans and measured in the range of 4000 to 400 cm-1, with a resolution of 4 cm-1.
description: sludge-FTIR.csv; Ecorr_icorr_pore solution.csv; Ecorr_icorr_pastes.csv; EIS-R-L pastes.csv; EIS-BFS-C-L pastes.csv; EIS-BFS-S-L pastes.csv; Raman-corrosion products.csv; XRD-pastes.csv; FTIR-pastes.csv; README_corrosion sludge.txt