The Frost-resisting Durability of High Strength Self-Compacting Pervious Concrete in Deicing Salt Environment

A high strength self-compacting pervious concrete(SCPC) with top-bottom interconnected pores was prepared in this paper. The frost-resisting durability of such SCPC in different deicing salt concentrations(0%, 3%, 5%, 10%, and 20%) was investigated. The mass-loss rate, relative dynamic modulus of elasticity, compressive strength, flexural strength and hydraulic conductivity of SCPC after 300 freeze-thaw cycles were measured to evaluate the frost-resisting durability. In addition, the microstructures of SCPC near the top-bottom interconnected pores after 300 freeze-thaw cycles were observed by SEM. The results show that the high strength SCPC possesses much better frost-resisting durability than traditional pervious concrete(TPC) after 300 freeze-thaw cycles, which can be used in heavy loading roads. The most serious freeze-thaw damage emerges in the SCPC immersed in the 3% of Na Cl solution, while there is no obvious damage in 20% of Na Cl solution. Furthermore, it can be deduced that the high strength SCPC can be used for 100 years in a cold environment.

Thermophysical, Mechanical and Durability Characterization of Adobe Bricks Reinforced with Fonio (Digitaria exilis) Sounds

Buildings constructed using modern materials such as cement are energy-intensive, facilitate heat transfer and thus promote warming inside the building. However, the Sudano-Sahelian regions have a hot climate occupying a large period of the year, thus requiring not only sustainable construction materials, but also which provide thermal comfort in the building by limiting the energy demand for air conditioning. These qualifications are important for sub-Saharan African countries in general and those of the Sudano-Sahelian zone in particular, which need ecological materials with good thermal performance to limit heating inside buildings. This study is an energy recovery of agricultural waste in buildings with a view to offering the populations of the northern regions of Cameroon suitable materials at lower cost for the construction of buildings. The soil used for this study was extracted from the locality of Yagoua where the populations make abundant use of mud bricks. Fonio waste was incorporated at low levels into the earth bricks, particularly at 0%, 1%, 2%, 3%, and 4%, with a view to strengthening their thermophysical and mechanical properties. The results obtained indicate that earth bricks reinforced with 4% waste showed better thermal and mechanical insulation properties compared to other formulations with an improvement of 16% and 78% respectively compared to the unreinforced samples. This research allows us to conclude that fonio waste can be used practically without expense in the building with a view to its energy recovery and will promote not only thermal comfort and the limitation of the energy supply for air conditioning, but the construction of more sustainable buildings with a cleaner environment.

Dual-Defect Engineering Strategy Enables High-Durability Rechargeable Magnesium-Metal Batteries

Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategies have been devised to enhance the Mg^(2+)migration kinetics and structural stability of cathodes,they fail to improve electronic conductivity,rendering the cathodes incompatible with magnesium-metal anodes.Herein,we propose a dual-defect engineering strategy,namely,the incorporation of Mg^(2+)pre-intercalation defect(P-Mgd)and oxygen defect(Od),to simultaneously improve the Mg^(2+)migration kinetics,structural stability,and electronic conductivity of the cathodes of RMMBs.Using lamellar V_(2)O_(5)·nH_(2)O as a demo cathode material,we prepare a cathode comprising Mg_(0.07)V_(2)O_(5)·1.4H_(2)O nanobelts composited with reduced graphene oxide(MVOH/rGO)with P-Mgd and Od.The Od enlarges interlayer spacing,accelerates Mg^(2+)migration kinetics,and prevents structural collapse,while the P-Mgd stabilizes the lamellar structure and increases electronic conductivity.Consequently,the MVOH/rGO cathode exhibits a high capacity of 197 mAh g^(−1),and the developed Mg foil//MVOH/rGO full cell demonstrates an incredible lifespan of 850 cycles at 0.1 A g^(−1),capable of powering a light-emitting diode.The proposed dual-defect engineering strategy provides new insights into developing high-durability,high-capacity cathodes,advancing the practical application of RMMBs,and other new secondary batteries.

Effect of slake durability on time dependent swelling behavior of red-bed siltstone in Sichuan Basin

The swelling behavior of red-bed rocks is a significant factor in the abnormal uplift of subgrades for high-speed railways constructed on the red stratum in the Sichuan Basin,China.The prime objective of this paper is to investigate the impact of mineralogical composition,moisture content,and overburden load on the time-dependent unconfined and oedometric swelling behavior of red-bed siltstone in the context of differences in the slake durability.Twenty samples were prepared for the swelling test,with eleven used for the unconfined swelling and slake index tests and nine for the oedometric swelling test.The temporal dependency of swelling is characterized by the viscosity coefficient of water absorption in a proposed swelling model.Results indicate that the swelling deformation of red-bed rocks is due to a combination of hydration swelling within the rock matrix and crack expansion caused by air breakage.In the unconfined swelling test,the final axial swelling strain of red-bed rocks decreases linearly with increasing slake index,while the viscosity coefficient increases exponentially with the slake index.In the oedometric swelling test,red-bed rocks with lower slake durability show greater sensitivity to lateral constraint and overburden load compared to those with higher slake durability.

Influence of Recycled Concrete Fine Powder on Durability of Cement Mortar

In this paper,the durability of cement mortar prepared with a recycled-concrete fine powder(RFP)was examined;including the analysis of a variety of aspects,such as the carbonization,sulfate attack and chloride ion erosion resistance.The results indicate that the influence of RFP on these three aspects is different.The carbonization depth after 30 days and the chloride diffusion coefficient of mortar containing 10%RFP decreased by 13.3%and 28.19%.With a further increase in the RFP content,interconnected pores formed between the RFP particles,leading to an acceleration of the penetration rate of CO_(2)and Cl^(−).When the RFP content was less than 50%,the corrosion resistance coefficient of the compressive strength of the mortar was 0.84-1.05 after 90 days of sulfate attack.But the expansion and cracking of the mortar was effectively alleviated due to decrease of the gypsum production.Scanning electron microscope(SEM)analysis has confirmed that 10%RFP contributes to the formation of a dense microstructure in the cement mortar.

Impact of typical environments in China’s western mountainous areas on the durability of railway concrete:a review

Purpose–This study aims to analyze the impact mechanism of typical environments in China’s western mountainous areas on the durability of railway concrete and propose measures to improve durability.Design/methodology/approach–With the continuous promotion of infrastructure construction,the focus of China’s railway construction has gradually shifted to the western region.The four typical environments of large temperature differences,strong winds and dryness,high cold and low air pressure unique to the western mountainous areas of China have adverse effects on the durability of typical railway structure concrete(bridges,ballastless tracks and tunnels).This study identified the characteristics of four typical environments in the western mountainous areas of China through on-site research.The impact mechanism of the four typical environments on the durability of concrete in different structural parts of railways has been explored through theoretical analysis and experimental research;Finally,a strategy for improving the durability of railway concrete suitable for the western mountainous areas of China was proposed.Findings–The daily temperature difference in the western mountainous areas of China is more than twice that of the plain region,which will lead to significant temperature deformation and stress in the multi-layered structure of railway ballastless tracks.It will result in cracking.The wind speed in the western plateau region is about 2.5 to 3 times that of the plain region,and the average annual rainfall is only 1/5 of that in the plain region.The drying effect on the surface of casting concrete will significantly accelerate its cracking process,leading to serious durability problems.The environmental temperature in the western mountainous areas of China is generally low,and there are more freeze-thaw cycles,which will increase the risk of freeze-thaw damage to railway concrete.The environmental air pressure in the western plateau region is only 60%of that in the plain region.The moisture inside the concrete is more likely to diffuse into the surrounding environment under the pressure difference,resulting in greater water loss and shrinkage deformation of the concrete in the plateau region.The above four issues will collectively lead to the rapid deterioration of concrete durability in the western plateau region.The corresponding durability improvement suggestions from theoretical research,new technology development and standard system was proposed in this paper.Originality/value–The research can provide the mechanism of durability degradation of railway concrete in the western mountainous areas of China and corresponding improvement strategies.

Durability evaluation for existing railway engineering: a review

Purpose – This study aims to analyze the factors, evaluation techniques of the durability of existing railwayengineering.Design/methodology/approach – China has built a railway network of over 150,000 km. Ensuring thesafety of the existing railway engineering is of great significance for maintaining normal railway operationorder. However, railway engineering is a strip structure that crosses multiple complex environments. Andrailway engineering will withstand high-frequency impact loads from trains. The above factors have led todifferences in the deterioration characteristics and maintenance strategies of railway engineering compared toconventional concrete structures. Therefore, it is very important to analyze the key factors that affect thedurability of railway structures and propose technologies for durability evaluation.Findings – The factors that affect the durability and reliability of railway engineering are mainly divided intothree categories: material factors, environmental factors and load factors. Among them, material factors alsoinclude influencing factors, such as raw materials, mix proportions and so on. Environmental factors varydepending on the service environment of railway engineering, and the durability and deterioration of concretehave different failure mechanisms. Load factors include static load and train dynamic load. The on-site rapiddetection methods for five common diseases in railway engineering are also proposed in this paper. Thesemethods can quickly evaluate the durability of existing railway engineering concrete.Originality/value – The research can provide some new evaluation techniques and methods for thedurability of existing railway engineering.

Influence of railway wheel tread damage on wheel-rail impact loads and the durability of wheelsets

Dynamic wheel-rail contact forces induced by a severe form of wheel tread damage have been measured by a wheel impact load detector during full-scale field tests at different vehicle speeds.Based on laser scanning,the measured three-dimensional damage geometry is employed in simulations of dynamic vehicle-track interaction to calibrate and verify a simulation model.The relation between the magnitude of the impact load and various operational parameters,such as vehicle speed,lateral position of wheel-rail contact,track stiffness and position of impact within a sleeper bay,is investigated.The calibrated model is later employed in simulations featuring other forms of tread damage;their effects on impact load and subsequent fatigue impact on bearings,wheel webs and subsurface initiated rolling contact fatigue of the wheel tread are assessed.The results quantify the effects of wheel tread defects and are valuable in a shift towards condition-based maintenance of running gear,and for general assessment of the severity of different types of railway wheel tread damage.

Preparation of Durable Antibacterial Polyester Fabrics by Grafting with the Natural Quaternary Ammonium Compound Betaine

Recently, the textile industry has increasingly advocated for natural resource-based healthcare textiles. This research presents a facile and eco-friendly approach to developing durable antibacterial polyester fabrics. Polyester fabric was first subjected to an alkaline hydrolysis to impart hydroxyl groups on the fiber surface. A natural antibacterial agent, betaine, was then covalently bonded to the hydrolyzed polyester fiber surface through esterification. XPS, Raman, SEM, and Wicking measurements were carried out to verify the esterification reaction. Antibacterial tests confirmed that betaine treatment grafted polyester fabrics revealed a remarkable antibacterial effect with inhibition rates > 99.9% against both E. coli and S. aureus and still remained inhibition rates of up to 91.5% against both bacteria after home washing for 20 cycles. Moreover, the modification significantly increased the capillary effect of polyester fabric but did not cause apparent adverse effects on the fabric’s hand or tensile strength. Overall, this grafting strategy for durable, antibacterial polyester fabric represents a significant practicality in the textile industry.

Dry Mix Slag—High-Calcium Fly Ash Binder. Part Two: Durability

This work investigates durability of cement-free mortars with a binder comprised of ground granulated blast furnace slag (GGBFS) activated by high-calcium fly ash (HCFA) and sodium carbonate (Na2CO3): the soundness, sulfate resistance, alkali-silica reactivity and efflorescence factors are considered. Results of tests show that such mortars are resistant to alkali-silica expansion. Mortars are also sulfate-resistant when the amount of HCFA in the complex binder is within a limit of 10 wt%. The fineness of fly ash determines its’ ability to activate GGBFS hydration, and influence soundness of the binder, early strength development, sulfate resistance and efflorescence behavior. The present article is a continuation of authors’ work, previously published in MSA, Vol. 14, 240-254.

Study on Durability of Recycled Aggregate Concrete in High-Temperature and Complex Environments

Recycled aggregate concrete refers to a new type of concrete material made by processing waste concrete materials through grading,crushing,and cleaning,and then mixing them with cement,water,and other materials in a certain gradation or proportion.This type of concrete is highly suitable for modern construction waste disposal and reuse and has been widely used in various construction projects.It can also be used as an environmentally friendly permeable brick material to promote the development of modern green buildings.However,practical applications have found that compared to ordinary concrete,the durability of this type of concrete is more susceptible to high-temperature and complex environments.Based on this,this paper conducts theoretical research on its durability in high-temperature and complex environments,including the current research status,existing problems,and application prospects of recycled aggregate concrete’s durability in such environments.It is hoped that this analysis can provide some reference for studying the influence of high-temperature and complex environments on recycled aggregate concrete and its subsequent application strategies.

Lightweight Design of Commercial Vehicle Cab Based on Fatigue Durability

To better improve the lightweight and fatigue durability performance of the tractor cab,a multi-objective lightweight design of the cab was carried out in this study.First,the finite element model of the cab with counterweight loading was established and then confirmed by the physical testing,and use the inertial reliefmethod to obtain stress distribution under unit load.The cab-frame rigid-flexible couplingmulti-body dynamicsmodelwas built by Adams/car software.Taking the cab airbag mount displacement and acceleration signals acquired on the proving ground as the desired signals and obtaining the fatigue analysis load spectrum through Femfat-Lab virtual iteration.The fatigue simulation analysis is performed in nCode based on the Miner linear fatigue cumulative damage theory.Then,with themass and fatigue damage values as the optimization objectives,the bending-torsional stiffness and first-order bending-torsional mode as constraints,the thickness variables are screed based on the sensitivity analysis.The experimental design was carried out using the Optimal Latin hypercube method,and the multi-objective optimal design of the cab was carried out using theKriging approximationmodel fitting and particle swarmalgorithm.The weight of the optimized cab is reduced by 7.8%on the basis of meeting the fatigue durability performance.Finally,a seven-axis road simulation test rig was designed to verify its fatigue durability.The results show the optimized cab can consider both lightweight and durability.

Mechanical Properties and Durability of Sustainable Concrete Manufactured Using Ceramic Waste:A Review

Green and sustainable concrete has attracted significant attention from the construction industry and researchers since it was proposed.The ceramic waste materials are often directly buried in the ground or placed in an open dump,and the accumulation of ceramic waste contributes to environmental pollution,which makes the recycling of ceramic waste quite urgent.Owing to the pozzolanic activity,excellent mechanical properties and durability,industrial ceramic waste is considered as a suitable substitute for cement or natural aggregates to fabricate renewable concrete.In this paper,the pozzolanic activity of ceramic waste and the workability,mechanical performance,and durability of ceramic concrete are discussed.In addition,the most recent research results pertaining to ceramic concrete are reviewed.Ground ceramic powder improves the workability,compressive strength,resistance to chloride penetration,and carbonation resistance of concrete to a certain extent.Concrete containing ceramic as the aggregate has a lower mechanical performance than ordinary concrete.However,the resistance to chloride penetration,freeze-thaw resistance,and high-temperature resistance of ceramic concrete are remarkable.Ceramic concrete is environmentally friendly,requires fewer energy resources to manufacture than ordinary concrete,and has excellent engineering properties.However,further research is required for future engineering applications.

Graphene quantum dots as sulfiphilic and lithiophilic mediator toward high stability and durable life lithium-sulfur batteries

The development of lithium-sulfur(Li-S) battery as one of the most attractive energy storage systems among lithium metal batteries is seriously hindered by low sulfur utilization, poor cycle stability and uneven redeposition of Li anode. It is necessary to propose strategies to address the problems as well as improve the electrochemical performance. One of the effective solutions is to improve the sulfiphilicity of sulfur cathode and the lithiophilicity of the Li anode. Herein, we reported that a synergistic functional separator(graphene quantum dots(GQDs)-polyacrylonitrile(PAN) @polypropylene(PP) separator)improved the electrochemical activity of sulfur cathode as well as the stability of Li anode. GQDs induced uniform Li^(+)nucleation and deposition, which slowed down the passivation of Li anode and avoided shortcircuit. Further, three-dimensional network constructed by electrospinning nanofibers and the polar functional groups of GQDs could both effectively inhibit the shuttle of LiPSs and improve the sulfur utilization. The stability of Li-S battery was improved by the synergistic effect. In addition, GQDs and electrospinning nanofibers protector increased lifetime of separators. Benefiting from the unique design strategy, Li//Li symmetric battery with GQDs-PAN@PP separators exhibited stably cycling for over 600 h. More importantly, the Li-S full batteries based GQDs-PAN@PP separators enabled high stability and desirable sulfur electrochemistry, including high reversibility of 558.09 mA h g^(-1)for 200 cycles and durable life with a low fading rate of 0.075% per cycle after 500 cycles at 0.5 C. Moreover, an impressive areal capacity of 3.23 mA h cm^(-2)was maintained under high sulfur loading of 5.10 mg cm^(-2). This work provides a new insight for modification separator to improve the electrochemical performance of Li-S/Li metal batteries.

A Review of the Advances Made in Improving the Durability of Welded Wood against Water in Light of the Results of African Tropical Woods Welding

Wood plays a major role in the production of furniture and wooden structures.Nevertheless,in this process,the massive use of adhesives and plural connectors remains a definite problem for health and the environment.Therefore,wood welding is a breakthrough in this respect.This paper reviews the applications of wood welding in furniture and construction and then examines advances in improving the durability of welded wood against water.Our contribution also highlights the need to join African tropical woods using the rotational friction welding technique.According to our results,these woods present interesting chemical singularities,which could provide solutions to the water vulnerability of the welded wood.Moreover,the use of such a joining method would first free the Cameroonian furniture industry from the chemical industry,secondly position it at the forefront of new eco-design trends and thirdly make it competitive with other countries in the Central African sub-region.These works enrich the long and rich bibliography on the technique of wood welding,which has long been conspicuous by its absence of tropical woods.

Ti-Fe_(2)O_(3)/Ni(OH)_(x) as an efficient and durable photoanode for the photoelectrochemical catalysis of PET plastic to formic acid

Photoelectrochemical(PEC) technology provides a promising prospect for the transformation of polyethylene terephthalate(PET) plastic wastes to produce value-added chemicals.The PEC catalytic systems with high activity,selectivity and long-term durability are required for the future up-scaling industrial applications.Herein,we employed the interfacial modification strategy to develop an efficient and stable photoanode and evaluated its PEC activity for ethylene glycol(EG,derived from PET hydrolysate) oxidation to formic acid.The interfacial modification between Fe_(2)O_(3)semiconductor and Ni(OH)xcocatalyst with ultrathin TiO_(x) interlayer not only improved the photocurrent density by accelerating the kinetics of photogenerated charge carriers,but also kept the high Faradaic efficiency(over 95% in 30 h) towards the value-added formic acid product.This work proposes an effective method to promote the PEC activity and enhance the long-term stability of photoelectrodes for upcycling PET plastic wastes.

Workability and Durability of Concrete Incorporating Waste Tire Rubber:A Review

Environmental problems caused by waste tires are becoming increasingly prominent.There is an urgent need to find a green way to dispose of waste tires,and scholars have made considerable efforts in this regard.In the construction industry,rubber extracted from waste tires can be added to concrete to alleviate environmental problems to a certain extent.As a new building material,rubber concrete has superior properties compared to ordinary concrete and has been widely used in many fields.Numerous studies have been conducted worldwide to investigate the effect of waste tire rubber on the performance of concrete.It has been reported that the addition of waste tire rubber has a significant influence on the performance of concrete.Workability influences the hardened performance of rubber concrete,especially the durability.Based on the current research results,the workability and durability of concrete manufactured with waste tire rubber,including water absorption and permeability,carbonation resistance,chloride ion permeability resistance,and freeze-thaw resistance,are summarized in this paper.It is concluded that the addition of waste tires has a negative effect on the workability of concrete.In terms of durability,concrete exhibits better chloride ion penetration resistance and frost resistance,with a higher water absorption rate,and lower anti-permeability and carbonation resistance owing to the addition of waste tire rubber.

Facile fabrication of durable superhydrophobic fabrics by silicon polyurethane membrane for oil/water separation

Nowadays, oil contamination has become a major reason for water pollution, and presents a global environmental challenge. Although many efforts have been devoted to the fabrication of oil/water separation materials, their practical applications are still hindered by their weak durability, poor chemical tolerance,environmental resistance, and potential negative impact on health and the environment. To overcome these drawbacks, this work offers a facile method to fabricate the eco-friendly and durable oil/water separation membrane fabrics by alkaline hydrolysis and silicon polyurethane coating. The X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy results demonstrate that silicon polyurethane membrane could be coated onto the surface of hydrolyzed polyester fabric and form a micro-/nano-scaled hierarchical structure. Based on this, the modified fabric could have a stable superhydrophobic property with a water contact angle higher than 150°, even after repeated washing and mechanical abrasion 800 times, as well as chemical corrosion. Moreover, the modified fabrics show excellent oil/water separation efficiency of up to 99% for various types of oil–water mixture. Therefore, this durable, eco-friendly and cost-efficient superhydrophobic fabric has great potential in large-scale oil/water separation.

Time-varying seismic fragility analysis of durability damage of high-tensile reinforcement ECC bridge pier

The deterioration of the performance of offshore bridges is particularly prominent due to the complex natural environment,including the coupling effects of earthquake and seawater erosion.In particular,bridge piers are the main energy-consuming and load-bearing components,so that excellent seismic capacity of bridge piers is the key to avoiding bridge damage.Although earthquake resistant behavior of ordinary reinforced concrete bridge piers(ordinary pier)can be improved by increasing the section size and reinforcement ratio of piers,the improvement of the earthquake resistant behavior is limited.To further improve the earthquake resistant behavior of bridge piers,high-tensile reinforcement engineered cementitious composite(ECC)bridge piers are utilized and time-varying seismic fragility analysis are conducted in this study.The refined model of a bridge pier is built by OpenSees.First,the influence of ECC replacement height on pier curvature is analyzed to determine the reasonable ECC height.Then,the time-varying fragility analysis of high-tensile reinforcement ECC piers(ECC composite piers)with durability damage are evaluated considering the time-varying law of materials.Four damage states,slight damage,moderate damage,extensive damage and complete collapse,are utilized in the study.These fragility curves indicate the durability damage can debase the earthquake resistant behavior of piers continually,the exceedance probability of the same state of destruction increases with the increase of peak ground acceleration(PGA)and service time of pier.The results also indicate that the corrosion level of chloride ion to pier is small during the early service period,and the bridge pier vulnerable curve is similar to that of the new bridge pier.As the level of chlorine ion corrosion deepens,transcendental probability is increased.Compared with the ordinary pier,the exceedance probability in each limit state of ECC composite piers is significantly reduced.The proposed ECC composite pies leads to better realistic time-varying earthquake resistant behavior.

Modification of Wood by Tannin-Furfuryl Alcohol Resins-Effect on Dimensional Stability,Mechanical Properties and Decay Durability

Furfurylation is a well-known wood modification technology.This paper studied the effect of tannin addition on the wood furfurylation.Three kinds of dicarboxylic acids,adipic acid,succinic acid,and tartaric acid,as well as glyoxal as a comparing agent,were used to catalyse the polymerisation of furanic or tannin-furanic solutions during wood modification.Impregnation of furanic or tannin-furanic solution at a certain concentration into the wood followed with curing at 103℃for a specific duration was performed for the wood modification.Different properties of the modified woods like dimensional stability,resistance of treatment to leaching,mechanical properties,decay durability against white-rot(Coriolus versicolor,Pycnoporus sanguineus)and brown-rot(Coniophora puteana)as well as their chemical and anatomical characteristics were evaluated.Results revealed that the partial substitution of FA by the tannins improved the fixation of the chemicals impregnated in wood.Further,dimensional stability,leaching resistance,Brinell hardness,modulus of elasticity/modulus of rupture,and decay durability properties of the furfurylated wood were also improved in the presence of tannins.Scanning electron microscopy revealed the deposition of the polymer in the wood lumen cells and in the wood cell walls.