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The incidence of "acid attacks" (vitreolage) is a global concern, with those affected often receiving lifelong medical care due to physical and psychological damage. The purpose of this study was to evaluate the effectiveness of several emergency skin decontamination approaches against concentrated (>99 %) sulphuric acid and to identify the effective window of opportunity for decontamination. The effects of four decontamination methods (dry, wet, combined dry & wet and cotton cloth) were assessed using an in vitro diffusion cell system containing dermatomed porcine skin. Sulphuric acid (H 2 SO 4) was applied to the skin with decontamination protocols performed at 10 s, 30 s, 8 min, and 30 min post exposure. Skin damage was quantified by tritiated water (3H 2 O) penetration, receptor fluid pH and photometric stereo imaging (PSI), with quantification of residual sulphur (by SEM-EDS) to determine overall decontamination efficiency. Skin translucency (quantified by PSI) demonstrated a time-dependent loss of dermal tissue integrity from 10 s. Quantification of dermal sulphur content confirmed the rapid (exponential) decrease in decontamination efficiency with time. The pH of the water effluent indicated complete neutralisation of acid from the skin surface after 90 s of irrigation. Wet decontamination (either alone or immediately following dry decontamination) was the most effective intervention evaluated, although no decontamination technique was statistically effective after 30 s exposure to the acid. These data demonstrate the time-critical consequences of dermal exposure to concentrated sulphuric acid: we find no practical window of opportunity for acid decontamination, as physical damage is virtually instantaneous. • Response to an acid exposure requires rapid intervention. • Immediate flushing with water reduces skin damage, other methods exacerbate damage. • Effectiveness of washing deteriorates as soon as 30 s following exposure to acid. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of chitosan addition on mortar performance during sulfuric acid attack. Twenty-four mortars were prepared using Brazilian portland cements, varying traces, and chitosan dosages ranging from 0% to 3%. Mortar expansion tests were performed to evaluate sulfuric acid attack resistance. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) were performed to evaluate the morphology, XDR was performed to confirm the FTIR results. Chemical structure and bending (3 points) and compressive tests were conducted to evaluate mechanical properties. The study demonstrated that mechanical properties as well the sulfuric acid-attack resistance are sensitive to the biopolymer incorporation, with noticeable effects even at low concentrations, 1% chitosan improves bending strength for CP V-ARI and CP V-ARI-RS in trace A, but decreases it for all cements in trace B, an outcome reflected in SEM images. FTIR results reveal lower levels of gypsum and ettringite formation in mortars with added biopolymer, except for CP V-ARI-RS. Tests on mortar expansion demonstrate that chitosan enhances sulfuric acid attack resistance by reducing mortar expansion by up to 60%. Practical Applications: The degradation of cement-based materials due to sulfuric acid-attack is a significant issue, as it leads to the formation of expansive products that progressively weaken concrete structures and increase its vulnerability to penetration by other substances. This research aims to investigate the impact of incorporating chitosan, a biopolymer, into mortar prisms in terms of sulfuric acid resistance. The study examines changes in mechanical properties, alterations in material structure, and the performance of mortars with and without chitosan when exposed to sulfuric acid attack. Findings indicate that both mechanical properties and resistance against sulfuric acid deterioration are influenced by the addition of biopolymer and chitosan enhances protection from sulfuric acid attack by reducing mortar expansion. This research has application on concrete structures subject to sulfate attacks present on soil and water. So, reservoirs, sewage treatment plants and pipes are some of the practical applications of this study. [ABSTRACT FROM AUTHOR]

The durability problems in Portland cement are related to decalcification of C–S–H; alkali-activated composites are proposed as alternative, focusing on acid exposure and resistance. They were prepared from recycled materials, basic oxygen furnace carbonated and desulfurization slags. The standard material is 100% metakaolin geopolymer compared to slag-based alkali-activated materials (AAMs) with and without reinforcement of fibers (basalt, and cellulose), added in 4 wt%. The acidic environments are H2SO4, HCl, and HNO3N = 2.14 (10, 7.5, and 12.5 wt%, respectively). The chemical resistance is improved by the addition of basalt fibers. The decrease in weight loss is 48% in HNO3 and 47% in HCl for AAM-Bas sample, while for AAM-Cell it is 9% in HCl and 34% in HNO3. The compressive strength of the AAM and AAM-Bas samples remains constant after HCl attack, while this acid attacks cellulose samples, which are stable in HNO3 and have a compressive strength of 10 MPa. [ABSTRACT FROM AUTHOR]

The geopolymerization reaction is a chemical process involving the dissolution of amorphous, semi-crystalline and crystalline phases following alkaline or acid attack at ambient or at low temperature (T˂100 °C). Together with precondensed entities of the used activator solution the dissolved parts form a geopolymer network which glues together all remaining unreacted parts as ingredients of the artificial stone. The fate of the mineralogical phases present in the precursors used in the synthesis of alkaline and acid geopolymers is reviewed in this article. The different starting materials used in the synthesis of geopolymers and the different techniques used to modify the reactivity of these materials are reported. The mineralogical evolution of the amorphous, semi-crystalline and crystalline phases after activation at ambient and at low temperatures (T < 100 °C) is also reported. This study shows that for the mineralogical investigation of raw material, precursors and geopolymers, XRD is the most widely used analytical method. The most commonly used method to confirm the participation of crystalline phases in geopolymerization is the comparison of the diffractograms of the raw material to those of the products. It also indicates that, in addition to the amorphous aluminosilicate phases, certain semi-crystalline, and crystalline phases participate in this geopolymerization dynamic either by undergoing total or partial dissolution to form an inorganic macromolecule with an amorphous structure of the zeolitic type and other new minerals. The composition of the phases formed depends on the base material. Increasing the synthesis temperature promotes the dissolution of phases, the formation of geopolymer networks, and in some cases, the formation of new phases such as sodalities, zeolite A and zeolite P. Little work has been done to quantify the mineralogical phases before and after precursor activation, making it impossible to assess dissolution, the degree of geopolymerization, and mineral formation. The exact structure of the phases formed is often questionable, as most of the papers do not mention their reference structure number. There is also a lack of quantification of the amorphous phase resulting from the hardening of the activating solution and the evaluation of the fraction of the amorphous phase contained in the precursor remains unreacted. The mineralogical investigation must also extend to the quantification of phases using Rietveld refinement with internal standards to correlate these with the physical and mechanical properties of geopolymer products. Additional mineralogical study techniques, such as thin sections, should be used in future work for in-depth mineralogical investigation of geopolymers. [ABSTRACT FROM AUTHOR]

This study focuses on the role of low-quality calcined Fanja (FNJ) clay in enhancing the behavior of cured cement mortar (CM) and its resistivity to chloride and sulfuric acid attack. Ordinary Portland cement was replaced with different quantities (10%, 25%, 35%, and 50% by weight) of FNJ, which was calcined at different temperatures (620 °C, 760 °C, and 900 °C). After 28 days of curing, all the hardened mortars were immersed in 5% sulfuric acid for up to 12 weeks. Additionally, a rapid chloride permeability test was conducted on the 91-day cured CM and CM-FNJ samples to evaluate the affinity of calcined FNJs to retard the chloride diffusion into CM. The results showed that all samples containing FNJ900 showed better physical and mechanical properties than the control sample, while CM with NFJ760 recorded nearly similar performance as CM-NFJ900. In contrast, the CM-FNJ620 mixtures showed lower properties than those of other mixtures. In addition to the pozzolanic reactivity of the calcined clay, the presence of hematite in the calcined clay strongly contributed to increasing the mechanical properties of the hardened mortar through forming calcium ferrosilicate hydrate binding phase, as confirmed by X-ray diffraction. Moreover, the existence of hematite increased the resistivity of CM against sulfuric acid attack as it acts as a buffer for an acidic medium. Compared with CM-FNJ900, the CM-FNJ760 is recommended for use as it exhibited a higher strength activity index and comparable resistance to accelerated chloride diffusion and sulfuric acid accompanied by lower energy demand and lower CO2 emission, achieving the concept of 'sustainability'. [ABSTRACT FROM AUTHOR]

The present study examined the effects of colloidal nanosilica on the performance of cement paste samples exposed to nitric acid for a continuous period of 28 days. Compressive strength and weight losses in paste samples as a result of this attack were determined to be 66% and 27%. The inclusion of nanosilica up to 6% by weight reduced these sample losses by densifying the microstructure with its pore filling and pozzolanic effects. The addition of nanosilica decreased the flow of cement paste by 30%, but improved compressive and flexural strengths at the end of 28 days by up to 45% and 118%. The acid attack on the cement sample resulted in the formation of a degraded layer surrounding the unaltered core material. X‐ray tomography images showed this zone formation, and the scanning electron microscopy images revealed the degraded microstructure. The results of the x‐ray diffraction and nanoindentation tests confirmed the complete decalcification of the main cement hydrates, including calcium silicate hydrate and portlandite, as a result of acid attack. The results obtained suggest that the incorporation of nanosilica strengthens the microstructure of the cement matrix, thus improving the service life of structural concrete operating in chemical environments. [ABSTRACT FROM AUTHOR]

The formulation of ultra-high-performance concrete necessitates the use of a high cement content. The alkaline nature of cement makes it susceptible to acid attacks. In addition, its high C3A content causes its vulnerability to sulfate attack under the development of expansive ettringite, where porosity plays an important role. The main objective of this study was to figure out how mass loss and dimensional instability affected the rate of reaction and its relationship to acid concentration. It is noted that in contrast to sulfuric acid attack, sulfate attack on ultra-high-performance concrete (UHPC) is characterized by the accumulation of sulfate ions near the surface until reaching a critical concentration known as the threshold value. However, the reaction effect was not remarkable, as attributed to the extremely low porosity. The effect of curing was found to have a minimal influence on acid resistivity because it is a kind of spontaneous acid-base reaction that cannot be alleviated. In this research work, the UHPC's service life can be predicted when exposed to different concentrations of sulfuric acid. When comparing acid and sulfate attacks, the latter becomes negligible. Despite the use of silica fume and fly ash, the reactivity with sulfuric acid was found to occur spontaneously and rely on cement content and acid concentration. A concentration of 2.5% sulfuric acid is the threshold concentration after which a substantial change in the development of strength takes place. Both reactions were monitored on different types of samples over time using several techniques, such as XRD, TGA, and DSC and optical microscopy. [ABSTRACT FROM AUTHOR]

To develop a sustainable geopolymer concrete (GC), the efficacy of using fine recycled concrete powder (FRCP) and recycled aggregates (RA) as partial replacements for fly ash (FA) and natural aggregates (NA), respectively, was investigated. The compressive strengths of different GCs were measured. The durability performance was assessed by means of capillary suction tests, initial surface absorption tests and acid attack performed at ambient curing. The compressive strength of the GC made with 50% RA (both coarse and fine) and FRCP was found to be comparable to that of GC made with NA. Similarly, the inclusion of FRCP in the GC mixes resulted in a pore-blocking effect, restricting water ingress to the GC through capillary suction and surface absorption, even with the use of 50% coarse RA and 25% fine RA. The results demonstrated that sustainable GC can be developed using appropriate doses of FRCP and RA. [ABSTRACT FROM AUTHOR]

Ketonization of biomass‐derived carboxylic acids offers a promising approach to remove oxygen and upgrade into valuable chemicals. However, the mechanism on Brønsted acid site (BAS) confined in micropores of zeolite remains elusive, due to the difficulty to observe the reaction intermediates experimentally and to locate the transition state via static density functional theory (DFT) calculations. Herein, ketonization of acetic acid on HBEA at 673 K was studied by metadynamics simulations based on DFT. The first reaction step was the concerted protonation and dehydroxylation of acetic acid, resulting in an electrophilic acylium cation and H2O (ΔG‡ = 1.53 eV). The subsequent likely steps, including C─C coupling through the nucleophilic attack of acetic acid (path I), ketene (path II), and 1,1‐dihydroxyethene (path III) toward acylium cation were tracked and compared. The high barriers for formation of more nucleophilic intermediates of ketene and 1,1‐dihydroxyethene made the overall path II and III less favorable than the direct coupling between acetic acid and acylium cation (path I, ΔG‡ = 2.15 eV). These results indicate that acylium cation is a key intermediate, and the C─C coupling between acetic acid and acylium cation via nucleophilic attack is the most favorable path on BAS confined in zeolite. [ABSTRACT FROM AUTHOR]

Thioesters are important in synthesis, materials science, and biology, and their preparation traditionally relies on the use of disagreeable thiols. Here, we report a thiol‐free protocol that stitches together widespread carboxylic acids and aryl halides, producing a diverse array of thioesters. Crucial to this strategy is the discovery that tetramethylthiourea can serve as both a sulfur source and, upon direct excitation by purple light, as a strong reductant, suitable for activating aryl halides via single‐electron transfer. Coupling of the resulting aryl radicals provides an isothiouronium ion intermediate, which can be attacked by carboxylic acids via a polar pathway, affording the thioester products under mild conditions. [ABSTRACT FROM AUTHOR]

Our bodies act as sites of identity formation as well as association with the world. It is the primary way of establishing a connection with our surroundings. On the surface, skin serves as a protective layer of the body, but it also becomes an embodiment of the person's identity. An acid attack is an act of violence that completely damages this protective shield of the body. The paper addresses the issue of vitriolage- how it disfigures the face and mutilates the very being of a person. The violent physiological disfigurement, especially that of the face, as it is an important front to place and assert oneself in society, leads to a complete disruption of one's socio-personal relationships. The critical study of texts undertaken is an attempt to understand the physical and psychological sufferings and resilience of the acid attack victim/survivor. As an extension of the psychological consequences of the experience, the victim starts comparing the human self with animalistic/monstrous tendencies. Facial disfigurement, in general, tends to arouse some affective response in public, ranging from pity and sympathy to disgust and distress. Drawing on some tenets of Erving Goffman's theory of stigma and Tobin Siebers' disability aesthetics as critical viewpoints, the paper examines the stigmatisation and repulsion in the form of disgust that individuals with disfigurement encounter and their ability to challenge and overcome these societal constructs. [ABSTRACT FROM AUTHOR]

Air sensitivity remains a substantial barrier to the commercialization of sodium (Na)-layered oxides (NLOs). This problem has puzzled the community for decades because of the complexity of interactions between air components and their impact on both bulk and surfaces of NLOs. We show here that water vapor plays a pivotal role in initiating destructive acid and oxidative degradations of NLOs only when coupled with carbon dioxide or oxygen, respectively. Quantification analysis revealed that reducing the defined cation competition coefficient (η), which integrates the effects of ionic potential and sodium content, and increasing the particle size can enhance the resistance to acid attack, whereas using high-potential redox couples can eliminate oxidative degradation. These findings elucidate the underlying air deterioration mechanisms and rationalize the design of air-stable NLOs. [ABSTRACT FROM AUTHOR]

Industrial metallic waste is a focus in civil engineering research, leading us to utilize it as building materials. High-Flow Sand Concrete (HFSC) has an economical cost, acceptable mechanical properties, and high workability. However, its drawback is the development of cracks, mitigated through the incorporation of fibers. To maximize the advantages, stainless steel shavings waste was utilized as fibers, specifically opting for Stainless Steel Fiber 316L (SSF-316L). The samples of HFSC were reinforced with SSF-316L fiber shavings at doses of 0.25%, 0.50%, 0.75%, 1.00%, 1.50%, and 2.00% by mass of concrete over 90 days During our research, we conducted tests to study the influence of SSF-316L on three properties (physical, mechanical and durability). Among the physical tests there is the determination of the air content, slump and density), at the level of the mechanical properties (we cite the compression, bending and traction tests), as for the durability we exposed our specimens to acid and sulfate, at the end the HFSC specimens were examined under a scanning electron microscope (SEM). The results show that there is a relative improvement in these three properties (physical, mechanical and durability). [ABSTRACT FROM AUTHOR]

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This study focuses on investigating the relationship between binder chemical composition, microstructure development in alkali-activated paste (AAP), and the sulfuric acid resistance of alkali-activated concrete (AAC). Experimental analyses, including x-ray diffraction, thermogravimetric, and scanning electron microscopy (SEM) tests, were performed on the AAP to understand the impact of critical chemical compositions on the formation of hydrotalcite, portlandite, CSH, and CASH during the alkali-activation process. The sulfuric acid resistance of AAC was evaluated through various tests, including compressive strength, porosity, chemical titration analysis, and weight loss tests. These tests aimed to assess the ability of AAC to withstand sulfuric acid attacks and investigate how the binder's chemical composition influenced its resistance to acid exposure. The results revealed that higher alumino-silicate ratios (Al/Si) and magnesium oxide (MgO) content in the binder composition led to increased amounts of hydrotalcite and CASH in the alkali-activated system when zeolite and metakaolin were used as replacement materials for slag. The AAC specimens with slag and metakaolin showed lower porosity at the same replacement ratio. The increased amounts of hydrotalcite and CASH in the AAC microstructure contributed to a reduction in the concentration of sulfate ions penetrating the AAC, leading to improved sulfuric acid resistance. This information can contribute to optimizing binder formulations for improving AAC's mechanical properties and durability in corrosive environments. Practical Applications: Concrete samples containing metakaolin and synthetic zeolite tested throughout this research project can be utilized in different construction and civil engineering applications, all with differing degrees of suitability. Metakaolin and synthetic zeolites can be used as a slag replacement in concrete samples and used in masonry bricks, commonly used in masonry walls, columns, and partitions. Furthermore, load-bearing or nonload-bearing masonry structures for building and civil engineering can also adopt the incorporation of AAC. Metakaolin and synthetic zeolite types utilized in this research project could also be applied to produce slag granular mixtures for use in the construction of roads and airfields. The requirements for the relevant constituents, composition and laboratory performance classification are specified in BS EN 12390-1:2019. [ABSTRACT FROM AUTHOR]

Acid resistance testing of concrete – development of a rapid testing method In many applications in agriculture, industry and waste water systems, concrete damage caused by acid attack is the decisive damage mechanism for durability. First, the cement paste on the concrete surface is decomposed by dissolving attack before a diffusion‐inhibiting covering layer forms between the surface and the attack zone. Hereafter, the damaging process progresses diffusion controlled and the damage zone advances into the concrete interior. Finally, progressive surface concrete erosion occurs which becomes decisive for the development of damage. In order to predict durability, it is essential to reliably record all three types of damage‐stages, including their interactions, as part of performance tests. However, this means that long test times of several months are inevitable, thus no meaningful chemical acid resistance tests for quality control are available. However, if the erosion behaviour for a specific concrete composition is known through performance tests, the test duration can be significantly reduced, e.g. for production control. This article presents such a suitable rapid test method for characterizing the acid resistance of concrete, which detects the early damage stages of acid attack quickly and cost‐effectively. The comparability and reproducibility of the test results are demonstrated and the application limits and possibilities are discussed. [ABSTRACT FROM AUTHOR]

Solid waste generation and its sustainable disposal are big concerns in the present decade. Mine tailings and incinerated bottom ash are among the greatest solid waste contributors to the environment. To promote sustainable development, material reuse and recycling are important. In the present study, a feasibility study was conducted by utilizing such tailings and bottom ash for the production of controlled low-strength material (CLSM). The amount of cement was utilized less, and by controlling the design mix with a targeted flow, low-strength material was produced. Three different cement contents (60, 80, and 100 kg/m3) and 100% mine tailings or incinerated bottom ash were used as fine aggregate material. Fresh properties of different CLSM mixes, mechanical performance, and leaching behavior were conducted to confirm the final product. It was observed that both the mine tailings and bottom ashes are suitable as an aggregate material for CLSM mixes. The compressive strength values of different CLSM mixes at 28 days were observed between 0.13 and 1.88 MPa for various aggregate materials (mine tailings and bottom ash) and cement content. Moreover, there is an influence in the reactivity of cement hydration by the aggregate (tailings and ash), which was confirmed by the calorimetry study. The selected mine tailings and bottom ashes are not inert (like natural aggregate) within the CLSM mixes, and the chemical composition of the raw materials affects their fresh and hardened properties. The leaching test further shows that the final product could leach different heavy metals beyond the limit for inert materials, but within the nonhazardous limits by international standards. The present work deals with CLSM mixes with locally available industrial side streams; some important properties such as hardening time, penetration resistance, shrinkage, excavatability, and other durability properties (i.e., acid attack, freezing and thawing resistance) were not considered in the study and can be studied further. [ABSTRACT FROM AUTHOR]

Corrosion and friction coefficient tests were performed on solid oak wood machined with hard-metal woodworking tools coated with PVD coatings (AlCrN, AlTiN, TiAlN, TiCN and CrN). The tannic acid attacks the carbide more intensively than the PVD coatings. During cutting, corrosion spreads on the cutting edge of the cutter due to mechanical action, which dissolves the cobalt binder of the hard-metal and causes the carbide grains to flake off. After 80 min of contact with the wood, the cobalt content decreases from 3.53 to 1.74%. Depending on the PVD coating material, cracks of 4 to 40 µm in width appear after 120 min (9000 m cutting path). After 120 min of machining, wear, corrosion effects and the influence of corrosion on the coefficients of friction were evaluated for tools with and without PVD coatings. TiCN is the most sensitive to corrosion, while AlCrN and CrN coatings are the least sensitive, with the AlTiN coating being the most affected under real cutting conditions (with mechanical + thermal + corrosion effects) and the tools with CrN and AlCrN coatings being the least affected. Corrosion affects the hard-metal and PVD coatings and reduces the coefficient of friction. The angle between the directions of sliding and sharpening of the cutting edge sharpening significantly influences this parameter. The coefficient of friction of hard-metal WC-Co and PVD coatings is higher in the parallel machining direction than in the perpendicular machining direction and ranges from 16.03% (WC-Co) to 44.8% (AlTiN). The coefficient of friction of hard-metal WC-Co decreases by 5.13% before and after exposure to tannic acid, while the corrosion of PVD coatings reduces it by 4.13% (CrN) to 26.7% (TiAlN). [ABSTRACT FROM AUTHOR]

The chemical, microstructural and mechanical characterization of novel lightweight composites produced by adding waste cork dust to a metakaolin-based geopolymeric matrix prepared by alkaline activation is presented. The alkaline activator solutions used for the reticulation of the 3D aluminosilicate network at room temperature are composed of NaOH and sodium silicate to maintain a low cost of the final composite. In this line, the research of the highest addition of waste, e.g. cork dust, is pursued starting from 1 and reaching a maximum content of 10 wt% over metakaolin. The chemical stability is evaluated in water as well as in HNO 3 or in H 2 SO 4 0.5 and 2.5 N solutions. The addition of cork does not affect the reticulation of the geopolymeric binder used as matrix, as is demonstrated by FT-IR and XRD analyses. The modification of the dense geopolymeric microstructure with the introduction of cork dust weakens the hardened composites that become more permeable to water and acid solutions increasing the weight loss after immersion and decreasing the mechanical resistance to compression. The mechanical performance of the hardened composite with 10 wt% of cork dust still seems to be sufficient for application as self-supporting thermal insulation panels. (195/200). [ABSTRACT FROM AUTHOR]

Propranolol is a pharmaceutical organic drug used for the treatment of high blood pressure, heart problems and anxiety diseases. The disposal of the expired drug threatens the environment, but still, it contains active components. The potentiality of the active components of the expired propranolol drug (EPD) has utilized to protect the mild steel corrosion in 1.0 M hydrochloric acid medium. Weight loss method, potentiodynamic polarization, ac-electrochemical impedance spectroscopy, scanning electron microscopy with energy disperse X-ray spectroscopy and atomic force microscopy (AFM) were used to investigate the expired propranolol drug's capacity to defend mild steel surfaces against corrosion in 1 M HCl medium. The outcomes of the studies demonstrate that expired propranolol drug efficiently inhibits the corrosion of mild steel in 1.0 M HCl medium at various temperatures and inhibitor concentrations. The maximum inhibition efficiency obtained by the weight loss method was 89.81% at 0.01 M EPD concentration at 303 K. EPD has been determined to follow the Temkin's adsorption isotherm model. The SEM–EDX and AFM images were indicated that the formation of protective layer on the surface of mild steel against the acid attack. Potentiodynamic polarization studies showed that the inhibition mechanism is mixed mode and predominantly cathodic control. The observed values of ∆G0ads, indicated that the inhibitive effect is exothermic and spontaneous. Furthermore, the determined thermodynamic parameters suggest that the adsorption process is spontaneous. [ABSTRACT FROM AUTHOR]

The study examines the impact of WGP on the resistance of mortar to sulfuric acid solution attack, with specimens containing 0%, 5%, 10%, 15%, 20%, 25%, and 30% WGP produced as cement substitutes. Some fundamental properties of mortar mixtures were evaluated, such as the pozzolanic activity index assessment, fresh density, water absorption, and compressive strengths during water curing times. Subsequently, the behavior characteristics of mortars when subjected to sulfuric acid solutions were assessed, including mass loss, residual compressive strength, visual inspection, and microstructure features during eight weeks of immersion in sulfuric acid. The results of the study indicated that the incorporation of WGP led to improved sulfuric acid resistance in the mortar. Furthermore, an increase in WGP content resulted in a reduced reduction in compressive strength against sulfuric acid attacks as the ages progressed. The study revealed that the mortar containing 5% WGP as a cement substitute had the highest compressive strength compared to other specimens, and using 10% WGP as a supplementary cementitious material was comparable to the control mixture. Finally, the microstructure tests indicated that the sample containing 5% WGP had a lower intensity of CH peaks than the reference sample. The study suggests that the optimum amount of GWP for strength and economic parameters is 5%, and 10% substitution, respectively. However, when considering acid solution resistance, 25% GWP cement replacement is the ideal content. [ABSTRACT FROM AUTHOR]

This study primary is to investigate the shear strength of self-compacting concrete (SCC) reinforced by steel-fiber (SF) and polypropylene-fiber (PPF) in different environmental conditions: the air, sulfate (MgSO4 with a concentration of 5%) and acid (H2SO4 with a concentration of 5%). The study also examines the effect of fiber volume fraction on the workability, shear strength, compressive strength, and splitting tensile strength of fiber reinforced SCC. The article aims to determine the durability effects of both fibers and their resistance to aggressive environmental conditions. The contribution of this article is an experimental investigation on the shear strength of SCC reinforced by SF as well as PPF in 3 different environmental conditions after 30 days of exposure. The study also investigated the fresh and mechanical properties of 5 different mixtures of SCC with/out 0.1% and 0.2% fibers. The study also concluded that PPF decreased the workability of SCC badly, and special care must be taken when selecting its volume fraction. Also, it was found that generally shear strength of SCC mixes enhanced with increasing SF and PPF volume fraction. Moreover, it was found that both fibers have good durability effects, and resist aggressive environmental conditions, with the best results obtained from samples containing 0.2% SF. In the air condition, while the compressive strength, shear strength and tensile strength results were 52.6MPa, 6.43MPa and 3.91MPa, in the sulfate condition those were 46.37MPa, 6.55MPa and 3.59MPa, and in the acid condition those were 34.4MPa, 5.5MPa and 3.46MPa, respectively. [ABSTRACT FROM AUTHOR]

The corrosion of alkaline concrete materials exposed to a sulfuric acid environment is becoming more and more prevalent, and its damage assessment is becoming more and more imperative. This study aims to describe the corroded surfaces of concrete with different strength grades (C30, C50, C80) in sulfuric acid environments in terms of their three-dimensional fractal dimension. Three kinds of concrete with varying strength grades, namely C30, C50, and C80, were immersed in a sulfuric acid solution with pH ≈ 0.85 for four distinct corrosion durations, specifically 0, 28, 56, and 165 days, in accelerated corrosion tests. The 3D laser scanning technique was utilized to capture the 3D coordinates of the surface points of the concrete cylinder before and after corrosion. The fractal dimension of concrete's uneven surface before and after corrosion was computed via the cube covering method, and the mass loss of the concrete specimen was also obtained. The outcomes demonstrate that the three-dimensional fractal dimension provides a new method for characterizing the degree of corrosion deterioration of concrete samples affected by sulfuric acid via laser scanning technology. From the perspective of the appearance, mass loss, and fractal dimension of a rough surface in the sulfuric acid environment at a pH level of approximately 0.85, the degree of the corrosion deterioration of concrete is ranked from high to low as C80 > C50 > C30. These fractal dimensions of the concrete's corroded surfaces with various strength grades increase rapidly in the initial period. However, as the corrosion time progresses, the growth rate of the corroded surface fractal dimension gradually decelerates and tends towards stability, which accords with the law of exponential function. The widespread belief is that the higher the strength grade of concrete, the better its durability; however, this pattern varies in sulfuric acid corrosive environments. Therefore, based on this research, it is recommended that in extremely acidic environments (i.e., very low pH), more attention should be paid to high-strength grades of concrete. [ABSTRACT FROM AUTHOR]

AbstractIn Mexico, the first attack dates back to 1988, but it was not identified until 2022. This violence remained invisible and minimized, but since then 42 acid attacks against women have been recorded, of which 5 victims died as a result of the attack and its medical complications. We think that families should be educated to eliminate misogyny in families and ensure that women are valued equally as men. We also think that education from childhood, questioning one’s own beliefs, challenging stereotypes and gender roles, deconstructing prejudices, reporting, and acting with empathy and compassion are fundamental in a society with gender equity. [ABSTRACT FROM AUTHOR]

This study explores the physiomechanical and durability properties of C-25 concrete by partially replacing cement with blends of pumice powder (PP) and bamboo leaf ash (BLA). The combined amount of major oxides SiO2, Al2O3, and Fe2O3 in PP is 84.59%, while in BLA, it is 74.4%, classifying PP and BLA as class N and F pozzolans. Subsequently, the study examines the impact of different cement replacement percentages, emphasizing 5%, 10%, 15%, and 20% on C-25 with varying mixes of concrete: Mix-1 (100, 0, and 0), Mix-2 (90, 5, and 5), Mix-3 (85, 10, and 5), Mix-4 (85, 5, and 10), and Mix-5 (80, 10, and 10) which correspond to the proportions of OPC, VPP, and BLA used in each mix respectively and by using 1 : 2.34 : 2.68 (cement : sand : aggregate) with the water/cement ratio (w/c) of 0.491. The study's findings indicate that as the proportion of PP and BLA increases in concrete, the workability of the mixture decreases. Moreover, on the 28th day, Mix-2 with (35.84 MPa) and Mix-3 with (33.55 MPa) met the desired mean compressive strength (33.5 MPa) required for C-25 concrete per the ACI standards. Additionally, the flexural strength of concrete produced with partial replacement of Mix-2 with a flexural strength of 3.86 MPa fulfills the minimum strength requirement of 3.5 MPa specified by the C-25 ACI standards. The PP and BLA blended concrete had lower water absorption than the control mix in Mix-2. It also improved resistance to sulfuric acid attack, and Mix-3 had the least strength reduction of 9.59%. In contrast, the control mix has a 33.34% strength reduction. [ABSTRACT FROM AUTHOR]

Despite numerous studies conducted on the potential of waste materials as cement substitutes, the resistance of mortars comprising such blended cementitious materials against acidic environments has seldom been investigated. This paper presents an investigation into the potential of waste glass powder (WGP) as a replacement for cement in enhancing the mechanical, and durability of cementitious materials subjected to acidic environments. The study examines the impact of WGP on the resistance of mortar to hydrochloric acid solution attack, with specimens containing 0%, 5%, 10%, 15%, 20%, 25%, and 30% WGP produced as cement substitutes. The tests were conducted on the cement mortar and paste after water curing for 7, 14, 28, 42, and 56 days. Initially, the pozzolanic activity index assessment, fresh density, water absorption, and compressive strengths during water curing times were evaluated. Subsequently, the performance of mortars, when subjected to hydrochloric acid solutions, was assessed, including mass loss, residual compressive strength, visual inspection, and microstructure features during 8 weeks of immersion in hydrochloric acid. The results of the study indicated that the incorporation of WGP led to improved hydrochloric acid resistance in the mortar. Furthermore, an increase in WGP content resulted in a reduced reduction in compressive strength against hydrochloric acid attacks as the ages progressed. The study revealed that the mortar containing 5% WGP as a cement substitute had the highest compressive strength compared to other specimens, and using 10% WGP as a supplementary cementitious material was comparable to the control mixture. Finally, the x‐ray diffraction pattern indicated that the specimen containing 5% WGP had a lower intensity of portlandite peaks than the reference specimen. [ABSTRACT FROM AUTHOR]

The current study presents an investigation into the optimal content determination of the mix parameters in their acceptable ranges through fresh, mechanical, and durability characteristics in ground granulated blast furnace slag (GGBFS) based self-compacting geopolymer concrete (SCGC) cured under ambient temperature. Ordinary portland cement (OPC) based self-compacting concrete (SCC) was prepared as a control concrete. Both the M25 SCGC and SCC were characterized through fresh property tests satisfying the flowability, passing ability, and segregation resistance; mechanical tests by both nondestructive and destructive tests; and durability tests through water absorption, sorptivity, acid attack, sulfate attack; and rapid chloride permeability test (RCPT). The prime mix parameters considered in SCGC with their variation ranges were molar concentration of sodium hydroxide (10M, 12M, 14M, 16M), sodium silicate to hydroxide ratio (1.5, 2.0, 2.5, 3.0), superplasticizer (SP) dosage (5%, 6%, 7%, 8%), and percentage of extra water (EW) (15%, 18%, 21%, 24%). The results of SCGC were compared with the control SCC and discussed. The mix parameter optimal values derived from all the fresh and hardened concrete properties were a 12M concentration of sodium hydroxide, sodium silicate to hydroxide ratio of 2.5, SP dose of 7%, and EW percentage of 21%. SCGC thus prepared is stable, workable, and exhibits superior properties to OPC-based concrete to promote sustainable development. The current study estimates the optimal quantity of mix parameters, i.e., 12M NaOH, AAS ratio of 2.5, 7% SP, and 21% EW to produce ground granulated blast furnace slag (GGBFS)-based self-compacting geopolymer concrete (SCGC) cured under ambient temperature. The SCGC-optimized mix-parametric values are evaluated based on the mix materials whose physical and chemical properties are declared in the manuscript. The cementless concrete thus prepared is GGBFS based, which is an industrial byproduct, yielding sustainable concrete. Under ambient temperature, the SCGC can be cured, which is practically beneficial for the in situ construction work. The self-compacting capability of SCGC involves minimal energy in producing a dense, smooth concrete surface, reducing both the construction period and cost involvement. Being a stable workable concrete, its nonsegregation nature makes it homogeneous with minimal entrapped air. The reduced permeability nature renders it a larger insulating potential. Concerning OPC-based concrete, SCGC has larger mechanical and durability characteristics, making it a better choice. Thus, the SCGC has a huge potential in the global construction sector and is practically applicable. [ABSTRACT FROM AUTHOR]

Introduction: Vitriolage or acid attack or acid throwing is a gender-based terrible violent crime. There are many everlasting sequels of vitriolage which consist of permanent scarring of the face or body, blindness as well as socioeconomic and psychological intricacy. The sufferer of acid attack is competitor, hatred, enmity or jealousy. Vitriolage are most common in the Asian countries especially in south east Asian region followed by Europe and South America. Bangladesh, India, Pakistan, Colombia and Cambodia are the countries having the highest incidence of acid attacks. There is a sharp rise in vitriolage cases in India in the last few years as indicated by data from the National Crime Record Bureau (NCRB). Seventy per cent victims of vitriolage are women in India as indicated by the annual reports of the Acid Survivor Foundation. Aims and Objective: The aim of the study was to report incidence of acid attacks in India, Indian states and metropolitan cities. To analyse various police and court procedure and to discuss various steps to give justice to the victim of vitriolage. Materials and Methods: Present study is a retrospective data record-based study. Available data for the last 5 years (from 2017 to 2021) were taken from National Crime Report Bureau (NCRB). Available as per NCRB, data were analysed as per aims and objectives. Results: The trend of incidence of acid attacks in India was decreasing in the last 5 years, that is, the incidence was 244 in the year 2017 which become 176 in the year 2021. West Bengal and Uttar Pradesh were the states having the highest number of acid attack incidence during the last 5 years. Delhi city was the top most metropolitan city having the highest acid attack incidence in the last 5 years. Police investigation of cases of acid attacks against women and cases disposed of by the police decreased in the last 5 years. The chargesheeting rate was better in metropolitan cities than overall chargesheeting in India. There was an increased trial of cases of acid attacks against women and a decrease in cases disposed of by the court during the last 5 years. Conviction rate by the court was better in India than the metropolitan cities of India during the last 5 years. Case acquitted by the court in India was 24, 9, 10, 4 and 10, and in metropolitan cities it was 2, 1, 3, 0 and 2 during year 2017, 2018, 2019, 2020 and 2021, respectively. Conclusion: Vitriolage not only destroys physical health but also destroys mental health. Despite of strict action taken by the Indian government, vitriolage is still prevalent in India. Male dominancy and inadequate legal systems are responsible for this. Though there is a standard set by the Supreme Court for the sale of acid, it remains easily available as the guidelines are frequently violated by the preparator. Case investigation and chargesheeting should increase by the police. Trial of the case and conviction should increase by the court. Vitriolage victims must be sure of their scope to obtain education and job opportunity and societal fiction should be reviewed to support people to acknowledge why vitriolage is committed mainly against females. [ABSTRACT FROM AUTHOR]

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Concrete is one of the most commonly used construction materials; however, its durability plays a pivotal role in areas where the concrete is exposed to severe environmental conditions, which initiate cracks inside and disintegrate it. Randomly distributed short fibers arrest the initiation and propagation of micro-cracks in the concrete and maintain its integrity. Traditional polypropylene fibers are thin and encounter the problem of balling effects during concrete mixing, leading to uneven fiber distribution. Thus, a new polypropylene fiber is developed by gluing thin ones together, forming macro-polypropylene fibers. Thus, different amounts of fibers, 0–1.5% v/f with an increment of 0.5% v/f, are used in different grades of concrete to study their impact on durability properties, including resistance to freezing and thawing cycles, sulfate, and acid attacks. A total of 432 cube samples were tested at 28, 56, and 92 days. The results reveal that the maximum durability, in terms of compressive strength loss, is noted with a fiber content of 1% with improved resistance of 72%, 54%, and 24% against freeze–thaw cycles, sulfate attack, and hydrochloric acid attack, respectively, at 92 days. Thus, the resulting fiber-reinforced concrete may be effective in areas where these extreme exposure conditions are expected. [ABSTRACT FROM AUTHOR]

Applying waste tire rubber as rubber aggregate (RA) in concrete is advantageous from the perspective of environmental sustainability. This study examines the action of graphene oxide (GO) on the durability properties of high-strength rubberised concrete (RC). The durability characteristics of concrete were assessed with the help of acid attack, water sorptivity, and rapid chloride penetration test (RCPT) on the hardened concrete specimens for the test periods of 7, 28, 56, and 90 days each. Acid attack tests (mass loss and compressive strength loss) were performed after immersing the concrete specimens in hydrochloric (HCl) and sulphuric (H2SO4) acids for the stipulated periods. The increased mass and compressive strength losses were observed with the incorporation of RA in concrete, which was finally mitigated by the action of GO in concrete. Water absorption was increased by RA alone but was reduced after the incorporation of GO in this RC. It was also observed that the chloride penetration was reduced after the incorporation of RA and GO in conventional concrete (CC). This study concludes that GO excellently strengthens the long-term durability properties of the RC. [ABSTRACT FROM AUTHOR]

This article analyzes the aging effect of HDPE sewer pipes when exposed to sulfuric acid at different temperatures. The mechanical properties, structural and morphological changes were evaluated. Results showed an impressive environmental degradation of HDPE. The tensile test showed that with a well-correlated increase in immersion time and higher temperatures, the elongation and ultimate stress of HDPE decreased. At 60 °C, the elongation at break indicated, at every time interval, an abrupt drop and a simultaneous loss of ductility. The micro-structural FTIR absorptions at 719-730, 1462-1472, 2848, 2916 and 3400 cm-1 were detected and compared using the spectrum of an unaged HDPE. The modification of the mechanical properties seems to correlate well with the structural observations obtained from the scanning electron micrographs. Eventually, it was discovered, via thermal aging studies, that the combination of temperature and sulfuric acid appears to be a major factor in high-density polyethylene breakdown. [ABSTRACT FROM AUTHOR]

Background: The preventive role of fluoride in caries control is mainly due to the formation of fluorapatite crystals which are more resistant to acid attack. Glass ionomer cement (GIC), its newer modifications, and certain composites in which fluoride has been incorporated show fluoride release. Aim: This research aims to compare the initial fluoride liberated, the fluoride liberated after recharge, and the mean percentage reduction of modified varieties of GICs along with fluoride-releasing composites. Materials and Methods: Forty specimen blocks of the materials to be tested were divided into 5 groups (n = 8), namely Group 1: Zirconomer (SHOFU), Group 2: GC GOLD Label Hybrid (GC), Group 3: Tetric Prime (Ivoclar), Group 4: Ketac Molar (3M), and Group 5: TE-Econom Plus (Ivoclar). The initial fluoride liberated was measured on the 1st day, after 1 week, and after a fortnight, using a benchtop analyzer and total ionic strength adjustment buffer III analyzer. Then, fluoride application was done with fluoridated dentifrice using the hand brush method, and the samples were rechecked for fluoride release at similar time intervals, i.e. 1, 7, and 15 days. Results: Zirconomer showed significantly higher initial fluoride release. The minimum mass of fluoride was released by TE-Econom. A similar pattern was observed for fluoride liberation after recharge, with Zirconomer showing maximum re-release of fluoride and TE Econom showing maximum reduction in fluoride release after 15 days. Conclusion: Zirconomer exhibited high initial fluoride liberation and fluoride liberation after recharge following topical fluoride application. GC Gold Label Hybrid and Ketac Molar showed the least percentage reduction in the biweekly fluoride liberation which was remarkably lower than Zirconomer. Fluoride-releasing composites showed the least amount of initial fluoride liberation and fluoride liberation after recharge. [ABSTRACT FROM AUTHOR]

Violence against women in India encompasses a range of abuses, including physical, sexual, and psychological harm. This analysis aims to shed light on the issue within India's patriarchal society, where such abuse has become normalized. Despite laws aimed at protecting women, their status often remains unchanged, highlighting the global crisis of violence against women as a grave human rights violation. Constitutional equality notwithstanding, Indian women still encounter significant obstacles, evidenced by rising violence rates. Discrimination, subjugation, and exploitation contribute to various violent acts against women. Crimes like rape and domestic violence persist, despite existing laws. This review also examines dowry issues, acid attacks, and eve-teasing, attributing them to gender bias, educational deficits, inadequate legal awareness, media influences, and financial instability. It suggests prevention strategies such as advocating for women's rights, enhancing education, strengthening legal systems, and empowering women. Raising awareness among women is crucial, enabling them to assert their rights and seek justice when violated. [ABSTRACT FROM AUTHOR]

This research aims to experiment with the integration of agricultural solid wastes into the manufacturing process of cementitious materials, ensuring that the resulting products exhibit satisfactory durability and mechanical properties. In this study, geopolymer composite (GP) was prepared using ground granulated blast furnace slag (BFS) and Arachis hypogaea (AH) fine dry peels as an example of agriculture waste is commonly available in Egypt. Some selected GP mixes were reinforced by nano magnetite (Fe3O4,NF). The prepared GP was cured for 28 days at two different circumferences, a normal curing at 25°C or hydrothermal curing at 60°C/0.02MPa. The setting times and compressive strength of the different types of manufactured general purpose (GP) were evaluated. The durability of the prepared GP against firing as well as H2SO4 acid (5%) attack were measured. The findings demonstrated that BFS/AH based GP offered diminished setting times and GP mixes hydrothermally cured at 60°C/0.02MPa adopted higher mechanical properties than those cured normally at room temperature. Besides, incorporation of AH dry peels up to 10% in GP manufacturing boosted the mechanical properties during the first 3 days for GP mixes cured at room temperature. Additionally, in comparison to the reference mix, the blended mix showed an accepted resistance to the effect of firing and astonishing resistance to acid attack. Admixing GP with 1% NF improved its durability in the two deterioration actions studied. [ABSTRACT FROM AUTHOR]

The present study utilized machine learning (ML) techniques to investigate the effects of eggshell powder (ESP) and recycled glass powder (RGP) on cement composites subjected to an acidic setting. A dataset acquired from the published literature was employed to develop machine learning-based predictive models for the cement mortar's compressive strength (CS) decrease. Artificial neural network (ANN), K-nearest neighbor (KNN), and linear regression (LR) were chosen for modeling. Also, RreliefF analysis was performed to study the relevance of variables. A total of 234 data points were utilized to train/test ML algorithms. Cement, sand, water, silica fume, superplasticizer, glass powder, eggshell powder, and 90 days of CS were considered as input variables. The outcomes of the research showed that the employed models could be applied to evaluate the reduction percentage of CS in cement composites, including ESP and RGP, after being exposed to acid. Based on the R2 values (0.87 for the ANN, 0.81 for the KNN, and 0.78 for LR), as well as the assessment of variation between test values and anticipated outcomes and errors (1.32% for ANN, 1.57% for KNN, and 1.69% for LR), it was determined that the accuracy of the ANN model was superior to the KNN and LR. The sieve diagram exhibited a correlation amongst the model predicted and target results. The outcomes of the RreliefF analysis suggested that ESP and RGP significantly influenced the CS loss of samples with RreliefF scores of 0.26 and 0.21, respectively. Based on the outcomes of the research, the ANN approach was determined suitable for predicting the CS loss of mortar subjected to acidic environments, thereby eliminating lab testing trails. [ABSTRACT FROM AUTHOR]

The present study aims to determine the effects of blending cementitious materials on the mechanical and durability properties of high-performance concrete (HPC). Densified silica fume and fine-grounded metakaolin are used as supplementary cementitious materials (SCMs). A total of 16 mixes containing both binary and ternary blending of SCMs were chosen for w/b ratios of 0.4 and 0.3 respectively. The hardened properties tested for the HPC mixes were compressive strength at 7, 28, and 90 days, flexural strength at 28 days, and modulus of elasticity at 28 days. Maximum strength gains up to 15%, 38%, and 23% for compression, flexure, and elastic modulus were observed in ternary mixes compared to binary mixes. Stress-strain behaviour of ternary mixes indicates increased tolerance of stress for the least amount of strain in the specimens. Based on the experimental results, empirical relations were developed and checked with the existing codes and by earlier researchers. The durability properties tested for HPC were water absorption at 28 days, acid attack, and sulphate attack at 28, 56, and 90 days. Ternary mixes improved the pore structure of HPC, resulting in a 56% reduction in water absorption and a 34% reduction in compressive strength loss due to immersion in 5% H2SO4 at 90 days. The findings of the study endorse that ternary blending of SF and MK can improve the engineering properties of HPC, and a mix containing SF 10% and MK 10% is recommended for the best results. [ABSTRACT FROM AUTHOR]

Compacted cement-bound soils (CCS) are widely used as leakage barriers around solid waste landfills and contaminated sites. However, a study of its long-term reliability in an acidic environment is relatively scarce. A 3-year-long experimental study on the changes in permeability coefficient and microstructure of CCS under acid attack was conducted, from which the following conclusions can be drawn: the permeability coefficient of CCS under weak acid (pH = 5.00) attack decreased progressively with time, from 4.90 × 10−8 cm/s at the beginning to 6.70 × 10−10 cm/s after 3 years. Under strongly acidic environments with pH values of 2.65 and 3.65, the permeability coefficients of CCS initially decreased and then increased with time, reaching 6.70 × 10−5 and 9.37 × 10−8 cm/s, respectively. The degradation effect of a weak acid (pH = 5.00) on the hydration products of cement was mild as a large amount of hydration products (e.g. C-S-H shaped in short fibrous) remained in the pores of CCS after 3 years of immersion. However, strong acid caused an obvious degradation effect on the hydration products, which almost disappeared after 3 years of immersion. Based on the study data, a unified mathematical model was developed to correlate the permeability coefficient of CCS, immersion time and acidic solution pH value. Furthermore, a quantitative expression function between the service life of CCS and solution pH value was established. [ABSTRACT FROM AUTHOR]

Self‐compacting concrete (SCC) is a type of flowable, high‐strength and high‐performance concrete in the construction field, which can flow and compact under its own weight. The damage of concrete is often caused by internal microstructural defects. Nano silica (NS) has excellent pozzolanic properties, and with an appropriate content of NS as auxiliary cementing material, it can promote the generation of C‐S‐H gels in addition to serve as internal filler, thus improves the micro‐scale defects in concrete. This paper extracts data from studies published over the last decade which focus on the application of NS in SCC and discusses the similarities and differences between the studies. Ultimately, a systematic review of the physical and chemical characteristics of NS, and the effect of NS on the workability, mechanical and durability properties of SCC is presented. Based on the review, the most common NS content is 0%–6%, where the negative effect of 0%–6% NS on the workability of SCC can be controlled by increasing the dosage of superplasticizer. The NS content of 2%–3% is optimum for improving the mechanical strength and the ability of SCC to resist water permeability, corrosion, acid and sulfate attacks, elevated temperature as well as shrinkage. [ABSTRACT FROM AUTHOR]

Geopolymers, known for their enhanced resistance to aggressive environment, are the subject of a new study to further increase their resistance by incorporating various raw materials. This research investigates the influence of waste glass content on the properties of alkali-activated binders exposed to an aggressive environment. The waste glass, replacing slag and metakaolin, was added in varying amounts ranging from 0 to 30 mass%. Sodium water glass, in the mass ratio of 4:5 to the binder, was used as the alkaline activator. The resistance to acid attack was assessed by immersing mortars in a sulfuric acid solution. The samples underwent analysis for appearance, mass and longitudinal change, compressive strength, and loss of alkalinity. Phase composition and microstructure were analysed using X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy techniques. Acid and water leachate was analysed by inductively coupled plasma mass spectrometry. The findings of the study revealed that incorporating waste glass content up to 20 mass% reduced porosity and affected the formation of gypsum. Gypsum results from the reaction between the binder and sulfuric acid and contributes to the surface deterioration of the specimens. Consequently, this research demonstrates that waste glass incorporation in the mix design can enhance the resistance of geopolymers to sulfuric acid, thus extending the service life of concrete structures. [ABSTRACT FROM AUTHOR]

Acid treatment of sepiolite under different molarity of HCl at various times was studied to find the best acid treatment conditions for obtaining anhydrous sepiolite without structural folding and with fully open and empty channels. It was found that high molarity (e.g., 3 M) acid treatment causes severe acid attack and heterogeneous magnesium dissolution from sepiolite particles. In contrast, the low molarity (e.g., 0.5 M) acid treatment dissolves magnesium homogeneously through the particles. This, in turn, affects the behavior of sepiolite upon calcination at 450ºC in that homogeneous magnesium dissolution gives better structural stability and consequently higher amount of open channels with the least amount of magnesium removal (25%). This is verified by rehydration behavior and specific surface area measurements after the calcination, where over 90% of the surface area could be preserved after the calcination of the low molarity acid-treated samples. No change in the morphology of sepiolite fibers was observed after acid treatment. [ABSTRACT FROM AUTHOR]

Aggressive environment reduces the mechanical and durability-related properties of concrete. In this study, the effects of exposing the concrete containing crumbed tire rubber (CTR) to aggressive environmental conditions, including hydrochloric acid (HCl) is investigated. For this purpose, 5, 10, and 15% of the fine aggregate of the mixing design were partially replaced with the CTR, and then at the age of 7 days, when the concrete reached almost 70% of the initial strength, the samples were placed in water containing 2% HCl for 28 and 90 days. In this study, the effect of using Nano-SiO2(NS) in the rubberized concrete and its behavior in acidic environments by replacing 5 and 10% by weight of cement with NS was also studied. Compressive strength and mass loss were evaluated at 28 and 90 days after casting. The results showed that the detrimental effects of HCl on the compressive strength of concrete significantly increased with an increasing in CTR content of concrete. The results also indicated that the impact of HCl acid on mass loss is improved by increasing the percentage of CTR so that the sample with the 15% crumbed tire showed a 7% lower weight reduction than the control sample. [ABSTRACT FROM AUTHOR]

In sewage pipelines, H2SO4 is formed by the action of H2S gas generated from sewage and bacteria inhabited on the walls, resulting in H2SO4 attack on the concrete above the sewage level. In Osaka city, Japan, it was found that the deterioration degree of sewage pipelines became greater in coastal areas. In the coastal areas, the groundwater derived from seawater flowed through the joints of the sewage pipes. We assumed that seawater with high Cl content may accelerate the deterioration of concrete by adding the effect of NaCl to H2SO4 attack. In this study, hardened cement paste specimens were immersed in a solution of 0.1 mol/L H2SO4 mixed with NaCl to clarify the effect of NaCl, the main component of seawater, on H2SO4 attack of concrete. The specimens were analyzed using EPMA, XRD, and FT‐IR after the immersion test, and the immersion solution was analyzed using ion chromatography. The deterioration degree of the specimens increased as the amount of NaCl added to H2SO4 increased. Relatively more gypsum was formed and delaminated under the condition of 2 % Cl addition. It has been reported that HCl causes the formation of highly soluble salt (CaCl2) and the dissolution of Ca. The addition of NaCl to H2SO4 is assumed to accelerate the deterioration degree of hardened cement paste by adding the effect of HCl acid. [ABSTRACT FROM AUTHOR]

The exposure of concrete structures to acid attack is a growing concern. This study employs thermodynamic modeling to investigate the changes in phase assemblage of powdered cement pastes subjected to a wide range of sulfuric and acetic acid concentrations. A modeling approach utilizing IPHREEQC implemented through Matlab is presented, and the obtained results are compared with pH measurements and compositions of equilibrated calcium and sulfate solutions. The influence of incorporating 11% silica fume (SF) as a replacement for cement predicted a 70% reduction of Portlandite content in the hardened cement paste. Consequently, the acid attack processes and subsequent pH reduction are affected. The modeling approach demonstrates good agreement with experimental data for acetic acid, across a broad range of acid concentrations, for both Portland cement and a blend with SF, without the need for any fitting parameters. However, significant discrepancies between the model and experiments are observed in the case of sulfuric acid. This discrepancy arises due to the formation of lump pieces of material in the experimental setup at higher acid concentrations. These lumps consist of a thin layer of altered hardened cement paste, primarily composed of sulfate‐rich phases, encapsulating unaltered hardened cement paste. Since the reaction was not homogeneous and the powder did not entirely react, the sulfuric attack experimental setup was not representative for validating the thermodynamic model. [ABSTRACT FROM AUTHOR]

A titration method is used to analyse the acid neutralization/consumption capacity (ANC) of cement binders, which involves plotting the steady‐state pH against the amount of acid added to a diluted suspension of hardened cement samples. Despite ANC being employed for several decades, there is no reported application of ANC for metakaolin‐based geopolymers. This study compares the resistance of metakaolin geopolymers to acetic acid and hydrochloric acid with that of Calcium Aluminate Cement (CAC) and Portland Cement (PC). The proposed ANC test setup involves small acid dosage steps using an auto‐titrator, resulting in a high‐resolution titration curve. The effect of binder chemical composition on acid resistance is evaluated through cumulative and differential ANC analysis, providing a new rapid approach to evaluate the durability of geopolymers in low pH environments. [ABSTRACT FROM AUTHOR]

The article discusses the rise of movies in India that depict scenes of sexual abuse and rape, often glorifying the acts and portraying them in a detailed and graphic manner. These movies often present rape as a tool for power and ownership, with the perpetrators being the sons of influential and powerful fathers. The article provides examples of such movies and highlights the negative socio-cultural impact they have, perpetuating violence against women and promoting the idea that women desire violence. The authors suggest that stricter filtering and certification by the Indian Censor Board, as well as the adoption of an accepted moral code by the media industry, could address this issue. [Extracted from the article]