شيماء عباس عبد السادة النايلي

The breakthrough and diffusion of chloride ions into reinforced concrete structures is the major contributing factor for inducing corrosion of the steel reinforcement. This work presents a study of the total chloride contents in concrete and the corrosion process by testing electrical resistivity and half-cell potential of concrete samples. The novelty of this work in the use of a green inhibitor—orange peel extract. The analysis was based on an experimental investigation of the samples with time of immersion in 3.5 wt% NaCl aqueous solutions at room temperature according to European Standards. For this study, different mixtures of concrete were prepared by adding two types of superplastisizers and green inhibitors in different concentrations. The results of the Cl− ions test showed that all the samples (except sample C2) after an immersion testing period of 6 months contained Cl− ions in high concentrations, indicating a greater risk of corrosion. Sample C2 (with green inhibitor and Oxydtron superplasticizer) showed the highest resistance against the chloride ion ingress measured by following the Cl− concentration changes up to the end of the 6 months testing period. This samples' good resistance to corrosion in the tested environment was also proved by the results of several sets of measurements of the electrical resistivity and half-cell potentials carried on the concrete test samples.

In recent years the use of inhibitors in producing high-performance concrete has increased significantly to mitigate chloride and sulphate attacks. The present inhibitors in the market are toxic to the environment. Hence, the objective of the present investigation was to study a novel, eco-friendly and green waste plant (orange peel) extracts inhibitor and study its effects on compression strength of reinforced concrete. This inhibitor was added to the concrete mix with concentrations of 1% and 3% by weight of cement with two types of superplasticizers. Results showed that the tested penetrating type corrosion inhibitor as an admixture of the concrete samples did not impair on compressive strength, but with one of the superplasticizers showed higher (acceptable) values compared to the other type of superplasticizer due to the difference between their ability in reducing the ratio of water of the concrete samples.

In this article, novolac nanoparticles with different weight fraction (0-40) wt.% were added to NBR/CR blends and investigate the effect of these additions on the specific gravity of rubber blend. The results obtained shown that the novolac nanoparticles works on increasing the specific gravity of NBR/CR blends, and specific gravity ratio increases with increased novolac nanoparticles percentage.

the applicability of a new organic inhibitor extracted from a cheap organic waste of orange peel (so-called „green” inhibitor) was studied in a laboratory system where the steel rebar samples obtained from a steel mill operating in Hungary were investigated in several sets of experiments to reveal their major corrosion properties in aqueous solutions containing sodium chloride salt. the initial corrosion rates were determined by a standard electrochemical polarisation technique on active (scale and rust free) steel specimen while being immersed in 3.5% nacl aqueous solutions containing the methanol extract of the chosen green inhibitor in a preliminary test run of 24 hours. Due to the inhibitor’s active groups identified by Ftir spectroscopy, this new green inhibitor (with concentrations tested at 1 and 3%) showed promising surface adsorptive and corrosion mitigating effects examined also by scanning electron microscopy (sem) combined with eDs surface analysis. these sem-eDs surface analyses were performed on the given rebar samples after an immersion (i.e. corroding) period of one month.

Due to the high cost of repair of damaged constructions, some preventive measures, namely using, for example, rice husks as corrosion inhibitor admixtures were chosen as a prospective preventive technique. Along this approach, laboratory concrete samples were so prepared and sent to mechanical testing, and concurrently, the inhibitive potential of the rice husks suspended in electrolyte solution (water with dissolved sodium chloride of 3.5 wt.%) was also tested by using a standard electrochemical corrosion testing technique, i.e. the powdered rice husk was added to the electrolyte solution in different dosages (1%, 2% and 3%), then the corrosion currents of the steel samples were recorded by using a three-electrode cell assemblage. In these laboratory tests a quite steady decreasing tendency could be observed in the measured corrosion current densities (Icorr) compared to the case when the electrolyte solution did not contain any inhibitor admixture (Icorr=41.3 µA/cm2; taken as the reference). For example, a corrosion current of Icorr = 28.5 µA/cm2 was measured at 1% rice husk concentration, and only Icorr = 7.8 µA/cm2 when the solution was mixed with 3% rice husk powder.

تم تقييم خمسة بحوث علمية لمجلة هندسة البناء الرصينة والمصنفة ضمن السفير وتقع ضمن الربع الاول