Papers by Keyword: Chloride

Abstract: With the continuous development of novel concrete formulations incorporating various materials, a prevalent issue is their susceptibility to deterioration, which often results in the formation of cracks within the internal structure. This study mainly explores the impact of liquid concrete deep-penetration sealer (CDPS) on the durability of concrete. The evaluation of durability included compressive strength tests, abrasion resistance tests, permeability tests, and rapid chloride ion penetration tests. Although compressive strength and permeability are conventionally regarded as the primary metrics for assessing concrete performance in the industry, abrasion resistance is often overlooked. To address this gap, this study incorporated abrasion resistance testing to ascertain the sealer's efficacy in mitigating surface wear. This barrier mitigates the ingress of deleterious external agents, thereby enhancing the overall durability of the concrete. Furthermore, the results highlight the potential of such treatments to significantly improve critical performance parameters, particularly in terms of wear resistance and resistance to chloride ion penetration, which are essential for prolonging the lifespan of concrete structures.

Abstract: Stainless steel may be susceptible to localized corrosion. Despite this fact, still too many infrastructures are planned with an inadeguate metal chemical composition or placed in wrong environments. In most cases, a clear underestimation of these factors affects the stainless steel durability. These unexpected issues cause a significant technical and economical impact. In this work, several case studies of Inox exposed to unfavorable environmental conditions are presented. A wide range of structures, such as house handles, a swimming pool, a parapet, an industry plant and a waste water collection tank are investigated with respect to the corrosion behavior. Temperature and humidity cyclic variation, promote the enrichments of aggressive agents and lead to degradation. A too low Molybdenum content of the steels is inadequate for some type of structures and service conditions. The weldability changes depending on the steel type and along the thermally affected zones, intergranular corrosion may appear. In addition, a galvanic contact of the stainless steel with existing low alloyed steels components promotes the deterioration of the latter.

Abstract: All-solid-state battery is a promising next-generation energy storage and conversion device and the development of solid electrolyte is very important as the core of all solid-state batteries. Herein lithium-indium chloride solid electrolyte is successfully prepared and the ionic conductivity is increased from 1.07 to 1.41 mS/cm by optimizing the vacuum parameter in the process of preparation. The samples have typical C2/m space group of cubic crystal system, and the vacuum optimized sample has more regular ion arrangement, better crystallinity and fewer lattice defects. The prepared sample is used as the electrolyte layer and the electrolyte part of the composite cathode, and the layered oxide LiNi_0.6Co_0.2Mn_0.2O₂ without surface modification was used as the active material. After assembling the cell, the initial discharge specific capacity of the cell was tested to be 157.5mAh/g. In addition, the phase transition of the composite cathode is analyzed under different charge and discharge state. It is found that the use of the lithium-indium chloride solid electrolyte in composite electrode does not affect the REDOX reaction of LiNi_0.6Co_0.2Mn_0.2O₂ layered oxide, indicating that the electrolyte material is stable and compatible with layered cathode material, showing its excellent application prospect.

Abstract: Concrete bridges are widely widespread as a main roadway infrastructure. The maintenance and the restoration or renewal of such artefacts are a major concern for the public administration. The reinforced concrete objects are exposed to detrimental atmospheric condition. The deterioration is different for the sixteen highway bridge elements. Some parts are sheltered or directly exposed to the atmospheric events, such as sun, rain, snow, salt spreading, splashing and washing. South-west sides or partially sheltered zones are more susceptible to cyclic temperature and humidity variation. This results in increased carbonation. The North-east sides, especially the curbs, are less carbonated because of enhanced presence of high humidity and are more prone to organic growth. The limit of 0.025 % of chloride content by concrete weight is exceeded in some bridge elements down to 40 mm, apart from the piles. Shoulders and curbs exhibit the highest Chloride content. Lower contents are observed for beams, struts and piles partially sheltered from the direct salt spreading action. A slight correlation exists between high Chloride content and low mean carbonation and depends on the humidity presence. This is observed for the shoulders, the shelves and the curbs, but less for the beams, the piles, the struts and the heads.

Abstract: In cement industry, the emissions of greenhouse gases specifically CO₂ from the clinker production led to the need of alternative binders. Geopolymer binder whose precursors are sourced from industrial by-products such as fly ash that are rich is silica and alumina has been studied extensively in the past decades. Chloride attack is one of the threats to concrete structures. Analysis at microstructural level needs to be studied carefully before this binder can be used with confidence. This study attempts to compare the properties of fly ash geopolymer binder when exposed in water and chloride solution. Fly ash geopolymer pastes were prepared using 12M sodium hydroxide (NaOH) as activator. The pastes were tested under two separate curing conditions, i.e in ambient and in distilled water. Compressive strength test along with microstructure properties of samples cured at 7, 14 and 28 days were conducted via Universal testing machine, Fourier Transform Infra-Red (FTIR) spectroscopy and Scanning Electron Microscope with Energy-dispersive X-ray (SEM-EDX). After 28 days of curing, these samples were immersed in 10% sodium chloride (NaCl) solution for another 56 days. Samples cured in ambient condition showed better mechanical performance than those in distilled water. Their differences in compressive strength were also seen consistent with the FTIR results. Samples exposed to NaCl and distilled water showed similar mechanical performance and microstructural properties. Based on SEM-EDX analysis, samples cured in ambient were rich in silica and alumina while the intensity of these compounds were observed to reduce when exposed to distilled water. Samples cured in ambient showed stronger intensity of Si/Al gel as compared to samples exposed to chloride environment and distilled water and these were consistent with the compressive strength results obtained. When immersed in water, concentration gradient changes in the liquid phases, leading to ions diffusion and causing decrement in strength and durability of the solids in fly ash geopolymer.

Abstract: In this study, quarternary ammonium salts based on triethylammonium and benzyltriethylammonium cations with the anion of chloride are successfully used for giant bamboo (Dendrocalamus Asper) preservation. These salts are new biocides as well as new salts which penetrate bamboo well. The prepared salts with hydrogen and benzyl substituent at the cation and consisted of chloride anion, exhibited fungicidal activity against Aspergillus Flavus. The effective and lethal doses were measured by the agar-plate method. In their activity against bamboo degrading fungi, salt of benzyl-triethyl-ammonium chloride was comparable with commercially available benzalkonium chloride and didecyldimethylammonium. Keywords: Triethylammonium, Benzyltriethylammonium, chloride, antifungal, and giant bamboo (Dendrocalamus Asper) and Aspergillus Flavus

Abstract: Cerium (Ce) doped ZnO is a promising material for advanced photocatalysis. It is useful for inducing the treatment of many organic pollutants in water. However, the stability of its performance under varying temperature and saline condition has never been not fully assessed. In this study, powder form photocatalyst comprising 99.0 mol% ZnO and 1 mol% CeO₂ has been synthesized via modified citrate gelation technique and solid-state sintering at 1200 °C for 5 hours. The conversion of Ce doped ZnO from its precursors has been confirmed using XRD, SEM, and EDX techniques. The photocatalytic efficiency of the synthesized Ce doped ZnO under UV-C light (λ=265 nm) was determined. In the experiment, the operating temperature was varied between 25 to 40 °C, and the salinity of the treated solution was increased from 0 to 40 g/L NaCl. The findings revealed that the photocatalytic efficiency of Ce doped ZnO under UV light improved from 78.2% to 88.6% as the temperature increased from 25 to 40 °C. The performance of Ce doped ZnO decreased from 86.7% to 36.7% when the salinity increased from 0 g/L to 40 g/L. The elevation of temperature encouraged the photogeneration of electron-hole pairs on catalyst surface while the presence of chloride ions in treated medium caused scavenging of hydroxyl radicals or hole.

Abstract: In this study, the effects of the specimen preparation method, temperature, and duration of the extraction step for the determination of the water-soluble chloride content of sea sand were investigated. The results demonstrated that increasing the heating temperature and duration promoted the dissolution of chloride, where the maximum value was obtained at 80°C and 60 min. Hot water extraction (80°C/60 min) could eliminate the effects of different specimen preparation methods on the final test results. Therefore, a new method was developed with drying at a temperature of 110 ± 5°C and hot water extraction at a temperature of 80°C for 60 min. The suitability of the new method for determining the water-soluble chloride content of sea sand was verified by testing the extracted specimens again. The results indicated that the chloride in sea sand dissolved fully with the new method, and thus it is suitable for testing the water-soluble chloride content of sea sand. Finally, the organic and inorganic compositions of the film adsorbed on the surface of sea sand were studied based on thermogravimetric analysis, inductively coupled plasma atomic emission spectrometry, ion chromatography, and total organic carbon measurements. The results indicated that a layer of substance (a multi-substance film) was adsorbed onto the surface of sea sand. This layer comprised inorganic salts (such as Cl^–, Na⁺, Mg²⁺, SO₄^2–, and Ca²⁺) and organic compounds, which were related to the composition of sea water. The multi-substance film greatly affected the dissolution and diffusion of chloride in the sea sand. Hot water extraction accelerated the dissolution of the film and increased the test results in terms of the water-soluble chloride contents.

Abstract: The corrosion characteristics of 316SS and 304SS in subcritical and supercritical aqueous systems including chloride of approximate 4600 mg/L at 25 MPa and 250 °C, 350 °C, 425 °C, and 520 °C are comparatively investigated. Some local corrosion areas occurred on the surfaces of SS316, not on that of 304SS, at 250 °C and 425 °C, while at 350 °C, all the sample surfaces were covered by large amounts of corrosion products and clay materials due to the predominant precipitation for the formation of the outer subscale. Whether in reducing subcritical and supercritical industrial sludge suspension or in oxidizing supercritical sludge system, 304SS owns better corrosion resistance than 316SS due to higher chromium concentration of former.

Abstract: Engineering in seawater face materials corrosion such as concrete and steel bars attacked. Corrosion ions such as chlorides and sulphates exist in seawater with high concentration leading to the durability of engineering made by reinforced concrete degradation. The paper analyzed the mechanisms of steel and concrete in seawater corroded by sulphates and chlorides. According to the conditions of seawater environment the suggestions and measures to develop the durability of the reinforced concrete are proposed from the aspects of structure styles, construction requirements and materials etc.