Acid Rain Corrosion Research Articles

Comparison on mechanisms of high-cycle fatigue performance of structural steel exposed to urban industrial atmosphere and laboratory simulated corrosive environment based on infrared thermography

The objective of this work is to analyze the high-cycle fatigue performance of the corroded base material without joints. Constant-amplitude axial tensile fatigue tests were conducted on 55 specimens obtained from the various environments. The infrared thermography was used to track the surface temperature of the specimens. When the corrosion degree is close, the accelerated corrosion test can simulate the atmospheric corrosion to predict the fatigue performance. The mechanism of discreteness of fatigue damage was analyzed from the perspective of energy dissipation. The S-N curves suitable for the Q235 steel in the acid rain corrosion environment are developed.

Axial performance degradation of squared CFST stubs in severe cold and acid rain area

The axial performance degradation of 40 concrete-filled squared thin-walled steel tubular stub columns in severe cold and acid rain area were studied in this paper. The test parameters include freeze-thaw cycles (0, 80, 160 and 240), corrosion rate (0, 10%, 20% and 30%) and wall thickness (3.0 mm and 4.5 mm). The test process involves three parts: only acid rain corrosion test, only freeze-thaw cycle test and alternation test of acid rain corrosion and freeze-thaw cycle. The results reflect that the failure modes of the specimens were the local buckling of the steel tube and the transverse tensile fracture at the corner of steel tube. Derived from the test results, the development of the rigidity, ductility and strength reduction factor of concrete-filled squared thin-walled steel tube with the different parameters were discussed, as well as the lateral deformation coefficient of the steel tube and the confinement effect of the core concrete. After validating the design methods in different standards, the modified Chinese standard prediction formula was recommended to evaluate the ultimate strength of concrete-filled squared thin-walled steel tube stub columns under the alternating action of acid rain corrosion and freeze-thaw cycle.

Municipal solid waste incineration fly ash exposed to carbonation and acid rain corrosion scenarios: Release behavior, environmental risk, and dissolution mechanism of toxic metals

This study investigated the leaching behavior, environmental risk, and dissolution mechanism of toxic metals (TMs) in solidified/stabilized municipal solid waste incineration fly ash (MSWI FA) exposed to alternative “carbonation + acid rain corrosion” disposal scenarios. The content of TMs (mg/kg) showed a trend of Zn (12,187.10 ± 168.60) > Pb (3374.43 ± 66.12) > Cu (1055.14 ± 32.52) > Cr (127.95 ± 8.12) > Cd (119.05 ± 6.26) > Ni (49.50 ± 3.20). Initial leaching of CO2-saturated water (CSW) and replacement of simulated acid rain (SAR) increased the environmental risk of leached TMs. The results of “average release rate” (mg/(kg·d)) of TMs indicated that Zn (0.8307)/Cu (0.0278)/Cd (0.0109) and Cu (0.0581)/Cr (0.001176)/Ni (0.004339) in phosphoric acid stabilized FA and Pb (0.0753)/Cr (0.001921)/Ni (0.00111) and Pb (0.0656)/Zn (1.0560)/Cd (0.0050) in Portland cement solidified FA were the key “problem TMs” during carbonation and acid rain corrosion, respectively. CSW leaching increased the independent environmental risk of most TMs in residual FA (especially Zn/Cd) due to the increased carbonate-bound fraction. Compared with independent carbonation, alternative “carbonation + acid rain corrosion” contributed to a higher comprehensive environmental risk for TMs in residual FA. CSW leaching system was an indirect carbonation based on CO2-water and FA matrix, in which “nucleation and dissolution” of carbonates and “immobilization and dissolution” of TMs coexisted. The dissolution mechanism of TMs was mainly controlled by reaction equilibrium of nucleation and dissolution of carbonates containing TMs. Dissolution and nucleation were the dominant mechanism in the early and later periods of CSW leaching, respectively. Carbonate layer dissolution, H+ corrosion/displacement, and counter-ion effect (SO42− > NO3− > Cl−) were the main mechanisms affecting TM dissolution during SAR leaching.

Experimental Study on Improvement Mechanism of Silane Emulsion on Acid Rain Corrosion of Green Ecological Concrete

Concrete structure is vulnerable to acid rain corrosion, which affects the service life of the material, in the corrosive environment, and concrete structure will deteriorate because of the erosion of water/chloride ions. Therefore, waterproof treatment of concrete structure is needed to improve the durability of the structure. In this study, the green ecological concrete is taken as the research object. The concrete is mixed with a certain amount of silane emulsion to reduce the probability of corrosion of concrete due to moisture and chloride ions, thereby prolonging the service life of this kind of concrete. During the experiment, in order to further test the corrosion resistance of silane emulsion to this kind of concrete, different kinds of concrete were taken as test objects and divided into 3 test groups, namely, the original test group (ITE), the non silane emulsion test group (TWSE) and the optimal ratio test group (OT-SE). It is proved by experiments that the best proportion of concrete mixed with silane emulsion is 0.32 of water binder ratio, 18% of coal powder mixing ratio, 37% of gravel mixing ratio and 0.23% of proportion of silane emulsion. The above factors are applied to compressive strength test, and 30 days as test time, the compressive strength of concrete with fly ash is measured. In the experiment of anticorrosion, compared with the traditional concrete samples, the electrical flux of concrete mixed with silane emulsion decreased by 28.7% in 8 h, that is, chloride ion permeability decreased significantly.

Deterioration mechanism of steam-cured concrete subjected to coupled environmental acid and drying action

In order to investigate the deterioration mechanism of steam-cured concrete under severe environmental actions such as acid rain corrosion, salt corrosion, and cyclic thermal loading, accelerated corrosion tests were conducted in this study. Surface damage as well as deteriorative kinetics of steam-cured concrete and cement paste suffering from coupled acid-thermal actions was investigated by soaking-drying cycle experiments. The effects of mineral admixture, curing regime and corrosion condition on the durability were all comparatively studied, and the X-ray diffractograms and nanoindentation were applied to analyse the mechanism of corrosion deterioration. The results revealed that compared with the cementitious materials under standard curing, larger depth and faster corrosion were observed for steam-cured concrete and cement paste, which might be partly attributed to the lower content of hydrated production presented in steam-cured specimens. Besides, under acid solution soaking-drying cycle regime, there was significant higher corrosion depth compared to only soaking in acid solution. The corrosion depth under steam curing and soaking-drying condition increased by 156.68% and 44.17%, respectively, compared with those under standard curing and only soaking treatment. In addition, fly ash effectively decreased the corrosion depth of steam-cured cement paste and concrete by 64.98% and 16.33%, respectively.

Effect of Acid Rain Pollution on Durability of Reinforced Concrete Structures

In order to solve the problem of insufficient accuracy and effectiveness of the current analysis model of the durability of reinforced concrete, the corrosion process of concrete by acid rain and the corrosion process of steel bars by acid rain are analyzed; based on the acid rain corrosion process, the structure of reinforced concrete composite beams under acid rain erosion Carbonization depth of medium concrete; Corrosion depth of reinforced concrete composite beam structure was obtained by carbonization depth; Durability index was calculated by carbonization depth and corrosion depth. It is suitable for analysis of the influence of acid rain pollution on the durability of reinforced concrete composite beam structures.

Effect of Surface State on Acid Rain Corrosion Resistance of T6 6005A Aluminum Alloy by BT-FSW Joint

The test sample was 5 mm thick artificial aging 6005A aluminium alloy profile, which was butted by BT-FSW. This work aimed to analyse the effect of surface state on corrosion resistance of welded joints in acid rain environment based on acetate ssalt spray test (CASS), polarization curve and EIS impedance test, combined with SEM scanning and EDS energy spectrum. The results showed that the corrosion rate of pre-welded polished joints was high at the initial stage of salt spray corrosion, and the corrosion rate of both joints were equal at the later stage of corrosion, higher than that of base metal. The best preservation of corrosion morphology was THAZ, followed by nugget zone and HAZ, and the pitting degree of base metal was the most serious. The polarization curves of the polished joints before 30 min corrosion were located at the lower right of the image, and its self-corrosion current density in the nugget zone showed the worst corrosion resistance. The corrosion resistance of the pre-welded polished joint increased after 336 hours of corrosion, the corrosion breakdown potential and self-corrosion current were not significantly different from those of the unpolished joints. The fitting curves of the two kinds of joints had similar dual capacitance arc resistance characteristics and the impedance parameters in EIS, and the electrochemical corrosion resistance of the two joints were weaker than that of the base metal.

Evaluation of concrete deterioration under simulated acid rain environment

Abstract Acid rain is identified as one of the most serious environmental problems nowadays and it is mainly a mixture of sulfuric and nitric acids. Deterioration of concrete structures exposed to aggressive acid rain attack is a key durability issue that affects the performance and maintenance costs of vital civil infrastructures. The motivation for understanding the acid rain corrosion process is high because of the early age deterioration of many concrete structures exposed to acid rain. The main objective of this study was to investigate the durability of concrete specimens with different supplementary cementitious materials, such as fly ash, zeolite and blast furnace slag against acid rain attack. Experiments of acid rain simulation influence on the composites were carried out for 7 weeks and parameters like visual changes, absorbability and leachability of calcium and silicon ions were evaluated. The increase in absorbability was detected for all samples while the sample with blast furnace slag was identified to be the most durable in this point of view. The most durable sample considering leached-out calcium and silicon ions was found to be sample with fly ash.

Prediction and Analysis of the Residual Capacity of Concrete-Filled Steel Tube Stub Columns under Axial Compression Subjected to Combined Freeze-Thaw Cycles and Acid Rain Corrosion.

This paper presents a theoretical investigation on the safety evaluation, stability evaluation, and service life prediction of concrete-filled steel tube (CFST) structures in a Northern China area with acid rain. The finite element software ABAQUS was used to establish a numerical model, which was used to simulate the axial compression behavior of CFST columns subjected to the combined actions of freeze–thaw cycles and acid rain corrosion. The model performance was validated using the experimental results of the evaluation of mechanical properties, including the failure mode and load–displacement curve. Then, the effects of the section size, material strength, steel ratio, and combined times on the residual capacity were studied. The results show that the section size has a smaller influence on the residual strength than the other parameters and can be neglected in the design procedure. However, the other parameters, including the material strength, steel ratio, and combined times have relatively large influences on the axial compressive performance of CFST stub columns subjected to a combination of freeze–thaw cycles and acid rain corrosion. Finally, design formulae for predicting the residual strength of CFST stub columns that are under axial compression and the combined effect of freeze–thaw cycles and acid rain corrosion are proposed, and their results agree well with the numerical results.

Mechanical Behavior of Brick Masonry in an Acidic Atmospheric Environment

In order to evaluate the deterioration regularity for the mechanical properties of brick masonry due to acid rain corrosion, a series of mechanical property tests for mortars, bricks, shear prisms, and compressive prisms after acid rain corrosion were conducted. The apparent morphology and the compressive strength of the masonry materials (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), the shear behavior of the masonry, and the compression behavior of the masonry were analyzed. The resistance of acid rain corrosion for the cement-lime mortar prisms was the worst, and the incorporation of fly ash into the cement mortar did not improve the acid rain corrosion resistance. The effect of the acid rain corrosion damage on the mechanical properties for the brick was significant. With an increasing number of acid rain corrosion cycles, the compressive strength of the mortar prisms, and the shear and compressive strengths of the brick masonry first increased and then decreased. The peak stress first increased and then decreased whereas the peak strain gradually increased. The slope of the stress-strain curve for the compression prisms gradually decreased. Furthermore, a mathematical degradation model for the compressive strength of the masonry material (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), as well as the shear strength attenuation model and the compressive strength attenuation model of brick masonry after acid rain corrosion were proposed.

Serviceability analysis of wood–plastic composites impregnated with paraffin-based Pickering emulsions in simulated sea water–acid rain conditions

In order to enhance the serviceability of sorghum straw/polyvinyl chloride composites in simulated sea water–acid rain conditions, paraffin-based Pickering emulsions stabilized by attapulgite particles were prepared as an anti-corrosion coating of the composites, and a worst-case simulated sea water and acid rain corrosion scenario was employed. The results showed that Pickering coating can have superior leaching resistance in the sea water-acid rain conditions. The coated composites had higher water-resistance and hardness than non-coated composites. The presence of Pickering coating resists the degradation effects of simulated corrosion through better water-resistance and hardness, as well as better mechanical and wear properties of the composites. Prior to the corrosion, the thermal stability of the composites was slightly reduced due to the presence of paraffin, while after 12 d corrosion, Pickering emulsions endowed the coated composites with higher thermal stability than non-coated composites.

Experimental Study on the Durability of Monorail Track Beam After Acid Rain Corrosion

An experimental study is proposed in this paper to investigate about the durability of monorail track beam after acid rain corrosion in a monorail transportation system. Firstly, a 20-m full-scale beam was built to analyze the causes of corrosion of a monorail track beam, and the corrosion pool was used to make a catalyzed corrosion test on the beam. Then the strand steels were contrasted after 3000-h of accelerated corrosion test. Next, experimental study was performed and the characteristics of strand corrosion in the monorail track beam with corrosion is discussed based on experimental observations. The results show that after the acid rain corrosion, the cross-sectional area of the prestressed steel strand was reduced, although the degree of corrosion was not serious compared with the plain bars, it was more dangerous because of high stress, so further research is necessary to clarify the effects of acid rain corrosion on the durability of the track beam.

Wear behavior of wood–plastic composites in alternate simulated sea water and acid rain corrosion conditions

To investigate the effect of alternate simulated sea water and acid rain corrosion on the wear resistance properties of wood–plastic composites, sorghum straw fiber-reinforced polyvinyl chloride (SPVC) composites prepared through extrusion molding were studied. The most detrimental alternating corrosion parameters were evaluated with the orthogonal design method, and the samples were then processed considering superimposed corrosion with the worst parameters. The results show that the worst alternating corrosion parameters were: sea water salinity 3.5% × sea water temperature 55 °C + acid rain pH 2.5 × acid rain temperature 55 °C. Longer alternating corrosion periods resulted in worse physical, mechanical, and thermal properties of the SPVC composites, a PVC matrix that was more easily softened in the frictional environment, and fibers more easily pulled-out to form abrasive particles. Debris of broken or pulled-out fibers moving with high-speed in a high-temperature and high-load frictional contact environment can cause severe abrasive wear.

Wear behavior of straw fiber-reinforced polyvinyl chloride composites under simulated acid rain conditions

In order to investigate the effect of simulated acid rain (SAR) corrosion on the wear-resistance properties of straw fiber/polyvinyl chloride (SPVC) composites, four types of straw fibers (wheat straw (WS), rice straw (RS), corn straw (CS), and sorghum straw (SS) fibers) were utilized and incorporated into poly(vinyl chloride) (PVC). The results show that the SS fibers have high levels of cellulose, lignin and crystallinity, and it also exhibited high adhesion strength with PVC matrix, which endow the SS/PVC with high wear-resistance compared with other three SPVC composites. After SAR corrosion, SPVC composites exhibited severe degradation of the physical, mechanical, and thermal properties, and the fibers were easily pulled out from the matrix to form abrasive particles. The high-speed fiber debris in high-temperature and high-loading environments can be deemed a kind of “incompressible lumps” that will form a certain abrasive wear.

Degradation mechanism of CA mortar in CRTS I slab ballastless railway track in the Southwest acid rain region of China – Materials analysis

Cement-emulsified asphalt mortar (CA mortar) is a key component of ballastless high-speed rail systems. Previous research illustrates acidic substances can provoke an intense deterioration on CA mortar. In order to investigate the relationship between acid rain environment and degradation mechanism of CA mortar in practical engineering, microstructure and organic-inorganic compositions of CA mortar collected from Chongqing and Chengdu were observed respectively. The degree of acid rain corrosion and thaumasite sulfate attack (TSA) were identified by analyzing the quantity and distribution of hydration products with XRD, SEM-EDAX, FTIR. The data of Ca(OH)2 X-ray diffraction intensity and weight loss of CA mortar in specific temperature range was used to calculate asphalt content. The asphalt components were examined using TG-DTA. Results showed that the loss of asphalt and asphaltenes under the coupling effects of loads and rain was one of the main reasons for the material degradation, instead of salt crystallization erosion or TSA caused by acid rain, neither the oxidation aging of asphalt. The results of this research will promote the microstructure optimization of CA mortar, and the development of the repairing material or technology to improve the maintenance system for high speed railways in different regions.

Analysis of Concrete Performance Used for Non-Ballasted Track Base Plate Based on the Coupling of Effect of Acid and Carbonization

Combining Shi Wu Passenger Dedicated Line and considering the effect of variety and content of mineral admixtures on concrete performance, the paper has investigated the microscopic structural’s variation of C40 high performance used in non-ballasted track base plate under the coupling conditions of acid rain and carbonization by using micro-testing methods such as SEM and XRD and optimizing mix design.The effect of variation on concrete performance has also been analyzed. Results show that when the concrete was eroded in coupling conditions of acid rain and carbon corrosion, C40 high performance concrete specimens produced a certain amount of acicular and columnar ettringite, the surface structure was loose, and pore increased, in addition, plate Ca(OH)2 crystal content gradually decreased with increasing of age, the concrete strength decreased, the maximum reducing value reached to 27%, what's more, the depth of neutralization increased with age. For different erosion pattern, its influence law was: S mode＜ST mode＜TS mode＜T mode.

Anti-Shear Reliability Analysis of Existing Pretension Prestressed Concrete Beam Bridges in the Corrosion Environment with Acid Rain

Under the acid rain corrosion condition, the shear-bearing capacity of the pretension prestressed concrete beam will attenuate gradually with the stirrup corrosion and concrete deteriorate. Moreover, the stress corrosion cracking failure and the bond force degradation of the prestressed wires that caused by the aggravated corrosion mediator ingress will further increase the shear failure risk of the pretension prestressed concrete structure without any symptom. The paper presents a shear bearing capacity calculation model of the pretension prestressed concrete beam bridge and discuss the time-variation model of the stirrup corrosion considering the effective prestress attenuation under the acid rain corrosion condition. The analysis method on anti-shear reliability of existing pretension prestressed concrete beam bridges under the sodium sulfate corrosion condition is proposed then. The method will be used in the durability and safety evaluation of the shear-bearing capacity of the existing pretension prestressed concrete beam bridges in the corrosion environment with acid rain.

Organic films for protection of copper and bronze against acid rain corrosion

In this paper, the anticorrosive effects of surface films formed on copper and bronzes by different organic inhibitors (mainly benzotriazole derivatives) are evaluated. Several alloys, nominally similar in composition to ancient artistic bronzes, were studied in comparison with copper. The protective efficiency of the organic coatings was tested by electrochemical ac and dc measurements performed both in acid and neutral rain. The experimental data show that benzotriazole derivatives with a long aliphatic chain form thin and very protective films on copper. The presence of the alloying elements (e.g. Sn, Zn, Pb) and multiphasic structures decrease the organic film performances. Nevertheless, among the compounds used, the most efficient, 5-octyl-1,2,3-benzotriazole (C8), seems to be a promising coating in the bronze conservation field.