This study investigates the use of crushed glass waste as partial cement replacement in ordinary concretes. Six concrete mixes were designed and prepared: a reference without substitution and five substitution percentages of crushed glass waste ranging from 5% to 25%. The made concrete mix design underwent different tests, namely: slump test, mechanical strength, thermogravimetric analysis (TGA), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) determination and finally, water porosimetry, in order to evaluate the influence of the use of crushed glass waste on the properties of fresh and hardened concrete. Mechanical strengths results show that the use of 15% of the crushed glass waste improves the mechanical strength. TGA analysis confirms this result by highlighting a higher hydration degree. The latter contributes to the reduction of the porosity and, consequently, the mechanical strength increases. Also, it can be caused by the increasing amount of chromium which, if added a little, accelerates the hydration of C3S and leads to an increase of the mechanical strength. The BET technique and porosimetry tests showed that the use of crushed glass waste reduces the global porosity of concrete. This is due to the filling effect of the glass powder.

Purpose: When concrete is manufactured, it can be instantaneously contaminated by chloride (Cl⁻) ions or later by their intrusion from the environment. This work aims to study the electrochemical behavior of the passive layer formed on the reinforcing steel surface in the presence of the same Cl⁻ ion concentration, with and without passivation time. This will, undoubtedly, affect the corrosion threshold values thereafter. Design/methodology/approach: Electrochemical polarizations were carried out in two concrete pore solutions. The surfaces of samples immersed for 255 days in saturated Ca(OH)₂ solution were examined with optical and scanning electron microscopy and Raman microspectroscopy. Findings: Cl⁻ ion origins in reinforced concrete lead to different values of corrosion thresholds. The passive layer behaves like a physicochemical barrier, and corrosion occurs at higher NaCl concentration thresholds. The formed passive film on the steel surface shows differences in the chemical composition and the morphology. The results show a rich presence of hematite. Maghemite, lepidocrocite, akaganeite and goethite are also present in much lower concentrations. The Cl⁻ ion presence in fresh concrete at the beginning of the manufacture harms the good formation and the good stability of these oxides, leading to corrosion initiation. Originality/value: This study contributes to a better understanding of the passive layer role, not only in reducing the corrosion rate value but also in reconsidering new Cl⁻ ion corrosion threshold values.

The modelling of chloride transport in concrete under an electrical field requires taking into account the electrode processes. These processes are very rarely introduced into the literature, despite their impact on chloride migration and the electroneutrality of the pore solution of the material. This paper aims to propose a multi-ion model for chloride migration that takes into consideration the electrode processes. The model is applied to simulate the standard chloride migration test. The generation of OH⁻ in the cathode and H⁺ in the anode allows for the monitoring of the electroneutrality. The model considers all of the ions in the pore solution. Ion fluxes are calculated using the Nernst–Planck equation. The Langmuir model is used to simulate the chloride isotherms. The thermodynamic equilibrium in the material is considered, which reflects the ion–solid interactions during the migration. Measurements of water porosity and the chemical composition of the pore solution are essential to provide input data and the initial and boundary conditions. The numerical results of the ion profiles in the material studied confirm the electroneutrality at any point within the material, in contrast with models that do not take the electrode processes into account. The proposed model allows for the more accurate simulation of the chloride migration test and electrochemical chloride extraction in reinforced concrete structures subjected to NaCl as part of maintenance and repair strategies.