This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw ...This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw resistance and durability of recycled concrete samples under varying freeze-thaw cycles.The results indicate that an appropriate addition of SAP significantly enhances the freeze-thaw resistance of recycled concrete.After 200 freeze-thaw cycles,the RS0.6 sample retained good surface integrity,demonstrating the best performance.Compared to NAC,its mass loss decreased by 1.16%,the relative dynamic modulus improved by 7.01%,and the compressive strength loss rate decreased by 5.41%.Additionally,T2 spectrum analysis revealed that adding SAP optimized the pore structure of recycled concrete and mitigated pore development during freeze-thaw cycles.As the number of freeze-thaw cycles increased,the RS0.3 and RS0.6 samples demonstrated superior frost resistance compared to NAC.However,an excessive amount of SAP increased pore expansion during subsequent freeze-thaw cycles,ultimately weakening frost resistance.展开更多
To study the durability of concrete in harsh environments in Northwest China,concrete was prepared with various durability-improving materials such as concrete anti-erosion inhibitor(SBT-TIA),acrylate polymer(AP),supe...To study the durability of concrete in harsh environments in Northwest China,concrete was prepared with various durability-improving materials such as concrete anti-erosion inhibitor(SBT-TIA),acrylate polymer(AP),super absorbent resin(SAP).The erosion mode and internal deterioration mechanism under salt freeze-thaw cycle and dry-wet cycle were explored.The results show that the addition of enhancing materials can effectively improve the resistance of concrete to salt freezing and sulfate erosion:the relevant indexes of concrete added with X-AP and T-AP are improved after salt freeze-thaw cycles;concrete added with SBTTIA shows optimal sulfate corrosion resistance;and concrete added with AP displays the best resistance to salt freezing.Microanalysis shows that the increase in the number of cycles decreases the generation of internal hydration products and defects in concrete mixed with enhancing materials and improves the related indexes.Based on the Wiener model analysis,the reliability of concrete with different lithologies and enhancing materials is improved,which may provide a reference for the application of manufactured sand concrete and enhancing materials in Northwest China,especially for the study of the improvement effects and mechanism of enhancing materials on the performance of concrete.展开更多
Graphene and its derivatives are two-dimensional nanomaterials with exceptional physical and chemical properties.Research has shown that their addition can counter the inherent deficiencies of cementbased composites,i...Graphene and its derivatives are two-dimensional nanomaterials with exceptional physical and chemical properties.Research has shown that their addition can counter the inherent deficiencies of cementbased composites,including low tensile strength,poor toughness,and high susceptibility to cracking.However,because of its high specific surface area and the van der Waals force between layers,graphene is prone to agglomerate in the cement matrix which can make the properties worse.Hence,improving the graphene dispersion is essential.The surface structure and properties of graphene and its derivatives are first introduced,and the different methods for their dispersion in cement-based materials are reviewed.Their effects on the mechanical properties and durability of cement-based materials are then summarized.Based on these results,the microscopic and nanoscopic mechanisms of the way graphene and its derivatives affect cement-based materials are elaborated.Current problems and future trends in this research area are then considered.展开更多
Batteries,as one of the most important classes of electrochemical energy storage systems,play a critical role in enabling energy sustainability and mobility.In recent years,we have witnessed a prosperous boom of resea...Batteries,as one of the most important classes of electrochemical energy storage systems,play a critical role in enabling energy sustainability and mobility.In recent years,we have witnessed a prosperous boom of research on battery chemistries and materials aimed at enhancing energy density,reducing costs,and enabling faster charging.While these advancements promote the applications of batteries in various engineering scenarios,they also raise significant safety concerns,particularly as higher energy densities increase the risk of catastrophic failures.Unfortunately,real-world incidents involving electric vehicles,consumer electronics,and largescale energy storage systems have demonstrated the devastating consequences of battery failures,where severe property damage and even loss of life are frequently observed.展开更多
Building and construction sector, including infrastructures, are facing many challenges which are scarcity of raw materials, CO2 emissions, lower construction efficiency, and deterioration under corrosive environment ...Building and construction sector, including infrastructures, are facing many challenges which are scarcity of raw materials, CO2 emissions, lower construction efficiency, and deterioration under corrosive environment that cost the world economy $2.5 trillion and this translates to 3.4% of world gross domestic product. This paper presents several examples that show how the use of the nonmetallic materials improved sustainability and life cycles in the built environment by removing the corrosion issue from its root and using durable NM polymers in construction. The paper details recently patented Aramco technology for the use of nonmetallic paving panels that could be used as an alternative to concrete and asphalt paving. Other case studies presented cover use of GFRP Poles for traffic signs and signal poles to replace traditional steel poles. Details of developments for specialist structural application in bridges, in architectural applications, polymers in soils, fibers in pavement manholes and bendable concrete are presented.展开更多
This study applied machine learning methods to predict the durability performance(specifically shrinkage and freeze-thaw resistance)of solid waste-activated cementitious materials.It also offered insights for optimizi...This study applied machine learning methods to predict the durability performance(specifically shrinkage and freeze-thaw resistance)of solid waste-activated cementitious materials.It also offered insights for optimizing material formulations through feature impact analysis.The study collected a total of 130 sets of shrinkage data and 106 sets of freeze-thaw data,establishing various models,including BP,GA-BP,SVM,RF,RBF,and LSTM.The results revealed that the SVM model performed the best on the test dataset.It achieved an R^(2) of 0.9358 for shrinkage prediction,with MAE and RMSE values of 0.4644 and 0.6254,respectively.Regarding freeze-thaw quality loss prediction,the R^(2) was 0.9178,with MAE and RMSE values of 0.3139 and 0.5328,respectively.The study analyzed the impact of different features on the outcomes using the SHAP method,highlighting that the alkaline activator dosage,Al_(2)O_(3),SiO_(2),and water glass modulus were critical factors influencing shrinkage,while CaO,water-cement ratio,water,and Al_(2)O_(3) were crucial for freeze-thaw resistance.By investigating feature interactions through single-factor and two-factor analysis,the study proposed recommendations for optimizing material formulations.This research validated the efficacy of machine learning in predicting the durability of solid waste cementitious materials and offered insights for material optimization through feature impact analysis,thereby laying the groundwork for the development of related materials.展开更多
Nitrogen-doped single-walled carbon nanohorns(N-SWCNHs)can serve as an effective carrier for platinum(Pt)catalysts,which has the potential to improve the electrocatalytic activity of oxygen reduction reaction(ORR)and ...Nitrogen-doped single-walled carbon nanohorns(N-SWCNHs)can serve as an effective carrier for platinum(Pt)catalysts,which has the potential to improve the electrocatalytic activity of oxygen reduction reaction(ORR)and the operation life of the catalyst.In this work,dahlia-like SWCNHs with N contents ranging from 2.1at%to 4.3at%are controllably synthesized via arc discharge and applied as a carrier of Pt nanoparticles(NPs),denoted as Pt/N-SWCNHs.Pt/N-SWCNHs-2:1(graphite and melamine with the mass ratio of 2:1)exhibits excellent electrocatalytic activity(onset potential=0.95 V).The half-wave potential of Pt/N-SWCNHs-2:1 is only reduced by 2 mV after 3000 cyclic voltammetry cycles.This can be attributed to the enhanced dispersion of Pt NPs and the strong electronic interaction between the N-SWCNHs and Pt,facilitated by the optimal nitrogen doping level.The results of this work offer important perspectives on the design and enhancement of Pt-based electrocatalysts for ORR applications,highlighting the critical role of the nitrogen doping level in balancing the electrocatalytic activity and long-term stability.展开更多
The valorization of Amazonian wood residues into active chemical compounds could be an eco-friendly,cost-effective and valuable way to develop wood preservative formulations to enhance the decay and termite resistance...The valorization of Amazonian wood residues into active chemical compounds could be an eco-friendly,cost-effective and valuable way to develop wood preservative formulations to enhance the decay and termite resistance of low-durable wood species.Wacapou(Vouacapoua americana.,Fabaceae)is a well-known Guianese wood spe-cies commonly used in local wood construction due to its outstanding natural durability,which results from the presence of a large panel of extractives compounds.In addition,its industrial processing generates large amounts of residues.Wacapou residues were extracted by maceration using four different solvents(water/ethanol,ethyl acetate,hexane and dichloromethane/methanol),separately and successively.The yield of each extractive fraction was determined,and their chemical compositions were analyzed by Liquid Chromatography-Mass Spectrometry(LC-MS).Ethyl acetate led to the highest extraction yield,and the active compounds were identified in the obtained extractive fraction.In this sense,the fungicidal and termite-repellent properties of these extractives were then tested using a screening laboratory(with temperate and tropical microorganisms),according to the solution concentration(1%,2.5%,5%,8%and 10%).Finally,Virola michelii Heckel wood samples(low durable species)were impregnated with the 8%concentration solution.The impregnated wood samples were then exposed to a soil bed test.The results highlighted that the nature of the solvent used during wood maceration affects the con-tent of the obtained extractive fractions.Ultra-Performance Liquid Chromatography–High-Resolution Mass Spectrometry(UHPLC-HRMS)analyses showed the influence of extraction parameters on the nature of the extracted molecules.Wacapou extracts(from ethyl acetate maceration)showed good anti-fungal and anti-termite activities.Additionally,the concentration in extractives had an impact on the anti-termite activity level for Reti-culitermesflavipes and Cryptotermes sp.Formulations based on Wacapou extractives showed a good potential for valorization in eco-friendly preservatives,aiming to confer better durability to local low-durability wood species.展开更多
Herein,a new method was developed for efficient and lasting fluorescent whitening cotton fabric by synthesizing and using a vinyl-containing fluorescent whitening agent to covalently grafting onto fiber surfaces with ...Herein,a new method was developed for efficient and lasting fluorescent whitening cotton fabric by synthesizing and using a vinyl-containing fluorescent whitening agent to covalently grafting onto fiber surfaces with the assistance of electron beam irradiation.The results from FT-IR spectroscopic,X-ray photoelectron spectroscopic,and energy dispersive spectrometric analyses showed that the fluorescent whitening agent was successfully anchored on cotton fiber via radiation-induced grafting copolymerization.The optimized whiteness value at 110.81(that of raw cotton fabric,74.50)was achieved using just 0.3 wt% fluorescent whitening agent.Notably,the whiteness value of the treated cotton fabric remained 110+even after 100 equivalent home-washing cycles,substantiating its excellent washing durability.Skin stimulation experiments on rabbits showed that the primary stimulation index of all experimental groups was 0 and no abnormal clinical symptoms were found in all tested rabbits,demonstrating the outstanding skin safety.Furthermore,energy generated by irradiation grafting technology was much lower than that of traditional processes and water consumption greatly reduced.Even the effluent from this process completely met the discharge standard of industrial wastewater without any treatment.This study explores a new method for textile finishing via electron beam irradiation,providing a green and sustainable perspective for the textile industry.展开更多
This study investigates the use of a low-carbon soil stabilizer called SDG,which is made up of granulated blast furnace slag (GGBFS),desulfurization gypsum (DG),and calcium carbide slag (CCS),to solidify the soil.The ...This study investigates the use of a low-carbon soil stabilizer called SDG,which is made up of granulated blast furnace slag (GGBFS),desulfurization gypsum (DG),and calcium carbide slag (CCS),to solidify the soil.The impact of SDG components on the strength and durability of solidified soil was analysed through a series of tests,including unconfined compressive strength,water stability coefficient,water absorption rate,drying-wetting cycles,and shrinkage tests.Furthermore,microstructure characteristics were analysed using X-ray diffraction (XRD) and scanning electron microscopy (SEM).The study shows that the solidified soil has excellent strength and durability when the SDG stabilizer contains 60% GGBGS,10% DG,and 30% CCS.Additionally,increasing the DG content negatively affects the soil's resistance to water.The SDG stabilizer has potential chemical cementitious characteristics and the calcium carbide slag is rich in calcium ions,which undergo an ion exchange reaction with minerals in the soil.These findings offer new ideas for the development of soil stabilizers.展开更多
Owing to their excellent biocompatibility and potential for durability enhancement,polymeric heart valves(PHVs)are emerging as a promising alternative to traditional prostheses.Unlike conventional materials,PHVs can b...Owing to their excellent biocompatibility and potential for durability enhancement,polymeric heart valves(PHVs)are emerging as a promising alternative to traditional prostheses.Unlike conventional materials,PHVs can be manufactured under precise design criteria,enabling targeted performance improvements.This study introduces a geometric optimization strategy for enhancing the durability of PHVs.The finite element method(FEM)is combined with a dip-molding technique to develop a novel polymeric aortic valve with improved mechanical properties.The tri-leaflet geometry is parameterized using B-spline curves,and the maximum stress in the valve is reduced from 2.4802 to 1.7773 MPa using a multiobjective optimization algorithm NSGA-II(non-dominated sorting genetic algorithm II).Pre-optimized and optimized valve prototypes were fabricated via dip-molding and evaluated during pulsatile-flow tests and accelerated wear tests.The optimized design meets the ISO 5840 standards,with an effective orifice area of 2.019 cm^(2),a regurgitant fraction of 5.693%,and a transvalvular pressure gradient of 7.576 mmHg.Moreover,the optimized valve maintained its structural integrity and functionality over 14 million cycles of the accelerated wear test,whereas the unoptimized valve failed after two million cycles.These findings confirm that the FEM-based geometric optimization method enhances both the mechanical performance and durability of PHVs.展开更多
By using the phased characteristics summarizing method of the existing research on magnesium slag,this study investigates the hydration reaction,alkali activation reaction and CO_(2) mineralization reaction processes ...By using the phased characteristics summarizing method of the existing research on magnesium slag,this study investigates the hydration reaction,alkali activation reaction and CO_(2) mineralization reaction processes and mechanisms,and then explores its high-value utilization.The results show that physical and chemical activation can improve the mechanical properties of the gelled material system by increasing the crystal phase defects and surface energy and by reconstructing a new gelling system by depolymerizing glass.The CO_(2) mineralization reaction of magnesium slag can be used to construct a new gelling system for CaCO_(3) and calcium-modified silica gel.Magnesium slag can also be used to enhance the dry shrinkage and carbonation resistance of concrete owing to its expansibility and high alkali reserves.The mechanism and existence form of heavy metal ions in magnesium slag have been clarified.The study proposed a production system for magnesium slag and highlighted the potential research value in the field of wet carbonation to promote the application of magnesium slag.展开更多
It is a good practice to change the site soil properties when dealing with inappropriate soils in geotechnical engineering,referred to as soil improvement.This study investigated the effects of epoxy resin LR202 stabi...It is a good practice to change the site soil properties when dealing with inappropriate soils in geotechnical engineering,referred to as soil improvement.This study investigated the effects of epoxy resin LR202 stabilizer(5 wt%of soil as an optimum percentage)and glass fibers(0 wt%,0.4 wt%and 0.8 wt%of stabilized soil)as reinforcement on silty sand’s durability.For this purpose,the unconfined compressive strength test(12 tests),durability test(12 tests),ultrasonic pulse velocity(UPV)test(48 tests),and standard compactions test(5 tests)were performed.The results of this study showed that the addition of epoxy resin improves the durability of silty sand soil.The stabilized samples containing 5 wt%epoxy resin resisted 12 freeze-thaw cycles,and the sample behavior was enhanced by adding 0.4 wt%and 0.8 wt%fibers to the stabilized samples.Hence,the samples stabilized with epoxy resin exhibited acceptable behavior under freeze-thaw durability cycles.This indicates that epoxy resin stabilizer is appropriate in areas with possible frost and exhibits good behavior.The results of the UPV test showed that it could be used as a non-destructive test to control the durability of epoxy resin-stabilized soils.展开更多
Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in ...Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in irreversible changes and deterioration on its endurance.Numerous studies unveiled that hydrophobic surface protection could be an inexpensive and effective way of enhancing the durability of concrete.This research work aims to assess the feasibility of bio-cement posttreatment for facilitating hydrophobic surface protection,thus enhancing the performance and durability of concrete blocks.Enzyme induced carbonate precipitation(EICP)is one of the promising bio-cement methods.Concrete blocks casted in four different grades were subjected to EICP treatment with different treatment schemes and recipes of cementation media.The treated blocks were tested for water absorption,ultrasonic pulse velocity(UPV)measurements,unconfined compressive strength(UCS),thermal performance,and scanning electron microscopy(SEM).The results indicated that the concrete blocks subjected to EICP posttreatment showed over a 55%reduction in water absorption,a 15%higher UCS and a 6.7%higher UPV when compared with control blocks.The SEM analysis suggested that the EICP posttreatment could enhance the durability of concrete paving blocks by enabling a layer of calcite on the surface and by plugging the transport pore channels of the concrete.Although most of the posttreatment strategies investigated herein were found to be operative,a better response was seen in the posttreatment by spraying scheme with 0.5 mol/L cementation media(CM).With the successful demonstration,the EICP treatment prior to the use of concrete blocks can be recommended to the pavement construction industry.展开更多
The launch of International Thermonuclear Experimental Reactor project paves the way to wide adoption of DT fusion energy as future energy source.Efficient fuel cycle to minimize strategic tritium inventory proves cru...The launch of International Thermonuclear Experimental Reactor project paves the way to wide adoption of DT fusion energy as future energy source.Efficient fuel cycle to minimize strategic tritium inventory proves crucial for commercially viable fusion technologies.ZrCo alloy is considered as a promising candidate for fast isotope handling.However,cycling degradation caused by hydrogen-induced disproportionation results in severe tritium trapping,thus impeding its practical application.Herein,an isostructural transition is successfully constructed with low hysterisis,ameliorated plateau flatness of pressure-composition isotherms and improved high-temperature durability for hydrogen trapping minimization.Specifically,the optimal Zr_(0.7)Hf_(0.15)Nb_(0.15)Co_(0.6)Cu_(0.15)Ni_(0.25) alloy adopts Hf-Nb and Cu-Ni as Zr and Co side doping elements,exhibiting substantial thermodynamic destabilization with nearly 90℃ reduction of delivery temperature,and significant kinetic promotion with a threefold lower energy barrier.More importantly,both hydrogen utilization and cycling retention of optimal alloy are increased by about twenty times compared with pristine alloy after 100 cycles at 500℃.Minimized disproportionation driving force from both isostructural transition and suppressed 8e hydrogen occupation realizes full potential of optimal alloy.This work demonstrates the effectiveness of combining isostructural transformation and high-temperature durability improvement to enhance the hydrogen utilization of ZrCo-based alloys and other hydrogen storage materials.展开更多
The effects of various fly ash(FA)contents on the durability and mechanical properties of recycled fine aggregate high ductility cementitious composites(RFA-HDCC)prepared with recycled fine aggregates(RFA)to fully rep...The effects of various fly ash(FA)contents on the durability and mechanical properties of recycled fine aggregate high ductility cementitious composites(RFA-HDCC)prepared with recycled fine aggregates(RFA)to fully replace natural fine aggregates was investigated.The results indicated that a 50% FA content significantly increased the compressive strength of RFA-HDCC by 13.93%.However,a?further increase in FA content led to a drastic decrease.The increased fly ash content substantially reduced the flexural and tensile strength;however,it markedly increased the matrix strain capacity,resulting in a 53.73% increase in the peak strain when FA was raised to 70%.Regarding durability,the increase in FA content negatively affected the chloride ion permeability and carbonation resistance.However,the increase in FA content initially improved the frost resistance of RFA-HDCC,peaking at 50% FA and deteriorating at 60% and 70% FA content.展开更多
In this paper,polyamide(PA)woven fabric was used as the base fabric,and polyurethane(PU)solution containing silica nanoparticles(PU@SiO_(2)NPs)was used as the coating solution to prepare composite tent fabric(PA/PU@Si...In this paper,polyamide(PA)woven fabric was used as the base fabric,and polyurethane(PU)solution containing silica nanoparticles(PU@SiO_(2)NPs)was used as the coating solution to prepare composite tent fabric(PA/PU@SiO_(2)).The morphology,structure,and durability of the tent fabric under ultraviolet(UV)radiation,waterstained,or thermal conditions were investigated.The results show that compared with PA/PU fabric without SiO_(2)NPs,when the mass fraction of SiO_(2)NPs in PU coating is 5%,the air permeability of PA/PU@SiO_(2)fabric decreases from about 7.5 to 6.0 nm/s,while the reflectivity to UVvisible light is significantly improved.The surface wettability decreases,as indicated by the average water contact angle(WCA)on PA/PU@SiO_(2)remaining stable at 47°after 9 min.After thermal treatment,the PA/PU@SiO_(2)fabric shows superior mechanical stability.The degradation rate of the tensile strength is only 6.3%,approximately half that of the PA/PU fabric.Meanwhile,the elongation at break increases to 98.9%,compared to 61.8%for the PA/PU fabric.展开更多
This paper presents an experimental study on the alkali-resistant properties of basalt fiber reinforced polymers （BFRP） bars under a typical concrete environment. BFRP bars were embedded in concrete and exposed to d...This paper presents an experimental study on the alkali-resistant properties of basalt fiber reinforced polymers （BFRP） bars under a typical concrete environment. BFRP bars were embedded in concrete and exposed to different aggressive environments, including tap water, saline solution and ambient temperature environments, to study the effects of the type of solution and relative humidity （RH） on the durability of BFRP. Meanwhile, BFRP bars were directly immersed in an alkaline solution for comparison. The acceleration factor describing the relationship between the alkaline solution immersion and the moisture-saturated concrete was also obtained. Aging was accelerated with a temperature of 60 ℃. The results show that the chloridion in the saline solution does not have any harmful effects on the degradation of the concrete-encased BFRP bars. Contact with an alkaline （high pH） concrete pore-water solution is the primary reason for the degradation of the BFRP bars. The degradation rate of concrete-encased BFRP bars is accelerated when a high temperature and a high humidity are present simultaneously. The degradation rate of the BFRP bars is relatively quick at the initial stage and slows down with exposure time. Results show that the degradation of 2.18 years in moisture-saturated concrete at 60 ℃corresponds to that of one year when directly immersed in an alkaline solution （other conditions remaining the same） for the BFRP bars analyzed.展开更多
A method for a vehicle durability emission test using a robot driver insteadof human drivers on the chassis dynamometer is presented. The system architecture of vehicledurability emission test cell, the road load simu...A method for a vehicle durability emission test using a robot driver insteadof human drivers on the chassis dynamometer is presented. The system architecture of vehicledurability emission test cell, the road load simulation strategy and the tele-monitoring systembased on Browser/Client structure are described. Furthermore, the construction of the robot driver,vehicle performance self-learning algorithm, multi-mode vehicle control model and vehicle speedtracking strategy based on fuzzy logic arealso discussed. Besides, the capability of controlparameters self-compensation on-line makes it possible to compensate the wear of vehicle componentsand the variety of clutch true bite point during the long term test. Experimental results show thattherobot driver can be applicable to a wide variety of vehicles and the obtained results stay withina tolerance band of ± 2 km/h. Moreover the robot driver is able to control tested vehicles withgood repeatability and consistency; therefore, this methodpresents a solution to eliminate theuncertainty of emission test results by human drivers and to ensure the accuracy and reliability ofemission test results.展开更多
The test results of eight concrete beams reinforced with carbon fiber reinforced polymer （CFRP） sheets subjected to an aggressive environment under a sustained load are presented. The beams are 1 700 mm long with a ...The test results of eight concrete beams reinforced with carbon fiber reinforced polymer （CFRP） sheets subjected to an aggressive environment under a sustained load are presented. The beams are 1 700 mm long with a rectangular cross-section of 120- mm width and 200-mm depth. The beams are precracked with a four-point flexural load, bonded CFRP sheets, and placed into wet-dry saline water（ NaCl） either in an unstressed state or loaded to about 30% or 60% of the initial ultimate load. The individual and coupled effects of wet-dry saline water and sustained bending stresses on the long term behaviour of concrete beams reinforced with the CFRP are investigated. The test results show that the coupled action of wet-dry saline water and sustained bending stresses appears to significantly affect the load capacity and the failure mode of beam strengthened with CFRP, mainly due to the degradation of the bond between CFRP and concrete. However, the stiffness is not affected by the coupled action of wet-dry cycles and a sustained load.展开更多
基金Funded by the Science and Technology Program of Gansu Province(Nos.25JRRA497,23ZDFA017)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0950000)High-level Talent Funding of Kashi。
文摘This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw resistance and durability of recycled concrete samples under varying freeze-thaw cycles.The results indicate that an appropriate addition of SAP significantly enhances the freeze-thaw resistance of recycled concrete.After 200 freeze-thaw cycles,the RS0.6 sample retained good surface integrity,demonstrating the best performance.Compared to NAC,its mass loss decreased by 1.16%,the relative dynamic modulus improved by 7.01%,and the compressive strength loss rate decreased by 5.41%.Additionally,T2 spectrum analysis revealed that adding SAP optimized the pore structure of recycled concrete and mitigated pore development during freeze-thaw cycles.As the number of freeze-thaw cycles increased,the RS0.3 and RS0.6 samples demonstrated superior frost resistance compared to NAC.However,an excessive amount of SAP increased pore expansion during subsequent freeze-thaw cycles,ultimately weakening frost resistance.
基金Funded by the National Natural Science Foundation of China(No.52178216)the Research on the Durability and Application of High-performance Concrete for Highway Engineering in the Cold and Arid Salt Areas of Northwest China(No.2022-24)the Construction Project of the Scientific Research Platform of Provincial Enterprises Supported by the Capital Operating Budget of Gansu Province(No.2023GZ018)。
文摘To study the durability of concrete in harsh environments in Northwest China,concrete was prepared with various durability-improving materials such as concrete anti-erosion inhibitor(SBT-TIA),acrylate polymer(AP),super absorbent resin(SAP).The erosion mode and internal deterioration mechanism under salt freeze-thaw cycle and dry-wet cycle were explored.The results show that the addition of enhancing materials can effectively improve the resistance of concrete to salt freezing and sulfate erosion:the relevant indexes of concrete added with X-AP and T-AP are improved after salt freeze-thaw cycles;concrete added with SBTTIA shows optimal sulfate corrosion resistance;and concrete added with AP displays the best resistance to salt freezing.Microanalysis shows that the increase in the number of cycles decreases the generation of internal hydration products and defects in concrete mixed with enhancing materials and improves the related indexes.Based on the Wiener model analysis,the reliability of concrete with different lithologies and enhancing materials is improved,which may provide a reference for the application of manufactured sand concrete and enhancing materials in Northwest China,especially for the study of the improvement effects and mechanism of enhancing materials on the performance of concrete.
文摘Graphene and its derivatives are two-dimensional nanomaterials with exceptional physical and chemical properties.Research has shown that their addition can counter the inherent deficiencies of cementbased composites,including low tensile strength,poor toughness,and high susceptibility to cracking.However,because of its high specific surface area and the van der Waals force between layers,graphene is prone to agglomerate in the cement matrix which can make the properties worse.Hence,improving the graphene dispersion is essential.The surface structure and properties of graphene and its derivatives are first introduced,and the different methods for their dispersion in cement-based materials are reviewed.Their effects on the mechanical properties and durability of cement-based materials are then summarized.Based on these results,the microscopic and nanoscopic mechanisms of the way graphene and its derivatives affect cement-based materials are elaborated.Current problems and future trends in this research area are then considered.
文摘Batteries,as one of the most important classes of electrochemical energy storage systems,play a critical role in enabling energy sustainability and mobility.In recent years,we have witnessed a prosperous boom of research on battery chemistries and materials aimed at enhancing energy density,reducing costs,and enabling faster charging.While these advancements promote the applications of batteries in various engineering scenarios,they also raise significant safety concerns,particularly as higher energy densities increase the risk of catastrophic failures.Unfortunately,real-world incidents involving electric vehicles,consumer electronics,and largescale energy storage systems have demonstrated the devastating consequences of battery failures,where severe property damage and even loss of life are frequently observed.
文摘Building and construction sector, including infrastructures, are facing many challenges which are scarcity of raw materials, CO2 emissions, lower construction efficiency, and deterioration under corrosive environment that cost the world economy $2.5 trillion and this translates to 3.4% of world gross domestic product. This paper presents several examples that show how the use of the nonmetallic materials improved sustainability and life cycles in the built environment by removing the corrosion issue from its root and using durable NM polymers in construction. The paper details recently patented Aramco technology for the use of nonmetallic paving panels that could be used as an alternative to concrete and asphalt paving. Other case studies presented cover use of GFRP Poles for traffic signs and signal poles to replace traditional steel poles. Details of developments for specialist structural application in bridges, in architectural applications, polymers in soils, fibers in pavement manholes and bendable concrete are presented.
文摘This study applied machine learning methods to predict the durability performance(specifically shrinkage and freeze-thaw resistance)of solid waste-activated cementitious materials.It also offered insights for optimizing material formulations through feature impact analysis.The study collected a total of 130 sets of shrinkage data and 106 sets of freeze-thaw data,establishing various models,including BP,GA-BP,SVM,RF,RBF,and LSTM.The results revealed that the SVM model performed the best on the test dataset.It achieved an R^(2) of 0.9358 for shrinkage prediction,with MAE and RMSE values of 0.4644 and 0.6254,respectively.Regarding freeze-thaw quality loss prediction,the R^(2) was 0.9178,with MAE and RMSE values of 0.3139 and 0.5328,respectively.The study analyzed the impact of different features on the outcomes using the SHAP method,highlighting that the alkaline activator dosage,Al_(2)O_(3),SiO_(2),and water glass modulus were critical factors influencing shrinkage,while CaO,water-cement ratio,water,and Al_(2)O_(3) were crucial for freeze-thaw resistance.By investigating feature interactions through single-factor and two-factor analysis,the study proposed recommendations for optimizing material formulations.This research validated the efficacy of machine learning in predicting the durability of solid waste cementitious materials and offered insights for material optimization through feature impact analysis,thereby laying the groundwork for the development of related materials.
基金financially supported by the National Natural Science Foundation of China(Nos.12175089 and 12205127)the Key Research and Development Program of Yunnan Province,China(Nos.202301AU070064 and 202103AF140006)the Yunnan Industrial Innovative Talents Program for“Xingdian Talent Support Plan”,China(No.KKXY202252001).
文摘Nitrogen-doped single-walled carbon nanohorns(N-SWCNHs)can serve as an effective carrier for platinum(Pt)catalysts,which has the potential to improve the electrocatalytic activity of oxygen reduction reaction(ORR)and the operation life of the catalyst.In this work,dahlia-like SWCNHs with N contents ranging from 2.1at%to 4.3at%are controllably synthesized via arc discharge and applied as a carrier of Pt nanoparticles(NPs),denoted as Pt/N-SWCNHs.Pt/N-SWCNHs-2:1(graphite and melamine with the mass ratio of 2:1)exhibits excellent electrocatalytic activity(onset potential=0.95 V).The half-wave potential of Pt/N-SWCNHs-2:1 is only reduced by 2 mV after 3000 cyclic voltammetry cycles.This can be attributed to the enhanced dispersion of Pt NPs and the strong electronic interaction between the N-SWCNHs and Pt,facilitated by the optimal nitrogen doping level.The results of this work offer important perspectives on the design and enhancement of Pt-based electrocatalysts for ORR applications,highlighting the critical role of the nitrogen doping level in balancing the electrocatalytic activity and long-term stability.
基金PROTEXTWOOD (ID 2202-102) funded through LabEx AGRO ANR-10-LABX-0001-01 (under ISiteUniversité de Montpellier framework)the project PANTHER2-Guyane funded through AgenceNationale de la Recherche (ANR-22-CE43-0019)+2 种基金“Investissement d’Avenir” grant managed by Agence Nationale de la Recherche (CEBA, ref. ANR-10-LABX-25-01)supported by the FEDER (European Regional Development Fund)research project “EcovaloBois” (Project number: GY0015430)by the CNRS peps INSIS2018 research project “GuyavaloFibres”.
文摘The valorization of Amazonian wood residues into active chemical compounds could be an eco-friendly,cost-effective and valuable way to develop wood preservative formulations to enhance the decay and termite resistance of low-durable wood species.Wacapou(Vouacapoua americana.,Fabaceae)is a well-known Guianese wood spe-cies commonly used in local wood construction due to its outstanding natural durability,which results from the presence of a large panel of extractives compounds.In addition,its industrial processing generates large amounts of residues.Wacapou residues were extracted by maceration using four different solvents(water/ethanol,ethyl acetate,hexane and dichloromethane/methanol),separately and successively.The yield of each extractive fraction was determined,and their chemical compositions were analyzed by Liquid Chromatography-Mass Spectrometry(LC-MS).Ethyl acetate led to the highest extraction yield,and the active compounds were identified in the obtained extractive fraction.In this sense,the fungicidal and termite-repellent properties of these extractives were then tested using a screening laboratory(with temperate and tropical microorganisms),according to the solution concentration(1%,2.5%,5%,8%and 10%).Finally,Virola michelii Heckel wood samples(low durable species)were impregnated with the 8%concentration solution.The impregnated wood samples were then exposed to a soil bed test.The results highlighted that the nature of the solvent used during wood maceration affects the con-tent of the obtained extractive fractions.Ultra-Performance Liquid Chromatography–High-Resolution Mass Spectrometry(UHPLC-HRMS)analyses showed the influence of extraction parameters on the nature of the extracted molecules.Wacapou extracts(from ethyl acetate maceration)showed good anti-fungal and anti-termite activities.Additionally,the concentration in extractives had an impact on the anti-termite activity level for Reti-culitermesflavipes and Cryptotermes sp.Formulations based on Wacapou extractives showed a good potential for valorization in eco-friendly preservatives,aiming to confer better durability to local low-durability wood species.
基金supported by the National Natural Science Foundation of China(Nos.12075153 and 11875313)CNNC Key Laboratory on Uranium Extraction from Seawater(No.KLUES202205).
文摘Herein,a new method was developed for efficient and lasting fluorescent whitening cotton fabric by synthesizing and using a vinyl-containing fluorescent whitening agent to covalently grafting onto fiber surfaces with the assistance of electron beam irradiation.The results from FT-IR spectroscopic,X-ray photoelectron spectroscopic,and energy dispersive spectrometric analyses showed that the fluorescent whitening agent was successfully anchored on cotton fiber via radiation-induced grafting copolymerization.The optimized whiteness value at 110.81(that of raw cotton fabric,74.50)was achieved using just 0.3 wt% fluorescent whitening agent.Notably,the whiteness value of the treated cotton fabric remained 110+even after 100 equivalent home-washing cycles,substantiating its excellent washing durability.Skin stimulation experiments on rabbits showed that the primary stimulation index of all experimental groups was 0 and no abnormal clinical symptoms were found in all tested rabbits,demonstrating the outstanding skin safety.Furthermore,energy generated by irradiation grafting technology was much lower than that of traditional processes and water consumption greatly reduced.Even the effluent from this process completely met the discharge standard of industrial wastewater without any treatment.This study explores a new method for textile finishing via electron beam irradiation,providing a green and sustainable perspective for the textile industry.
基金Funded by the National Key R&D Program of China (No. 2022YFC3803405)the China State Construction Key Laboratory Project (No. ZJXJ-PT-2022-14)。
文摘This study investigates the use of a low-carbon soil stabilizer called SDG,which is made up of granulated blast furnace slag (GGBFS),desulfurization gypsum (DG),and calcium carbide slag (CCS),to solidify the soil.The impact of SDG components on the strength and durability of solidified soil was analysed through a series of tests,including unconfined compressive strength,water stability coefficient,water absorption rate,drying-wetting cycles,and shrinkage tests.Furthermore,microstructure characteristics were analysed using X-ray diffraction (XRD) and scanning electron microscopy (SEM).The study shows that the solidified soil has excellent strength and durability when the SDG stabilizer contains 60% GGBGS,10% DG,and 30% CCS.Additionally,increasing the DG content negatively affects the soil's resistance to water.The SDG stabilizer has potential chemical cementitious characteristics and the calcium carbide slag is rich in calcium ions,which undergo an ion exchange reaction with minerals in the soil.These findings offer new ideas for the development of soil stabilizers.
基金funded by the National Natural Science Foundation of China(No.82400370)the Interdisciplinary Innovation Team Incubation Project of Children’s Hospital of Fudan University(No.EKYX202416).
文摘Owing to their excellent biocompatibility and potential for durability enhancement,polymeric heart valves(PHVs)are emerging as a promising alternative to traditional prostheses.Unlike conventional materials,PHVs can be manufactured under precise design criteria,enabling targeted performance improvements.This study introduces a geometric optimization strategy for enhancing the durability of PHVs.The finite element method(FEM)is combined with a dip-molding technique to develop a novel polymeric aortic valve with improved mechanical properties.The tri-leaflet geometry is parameterized using B-spline curves,and the maximum stress in the valve is reduced from 2.4802 to 1.7773 MPa using a multiobjective optimization algorithm NSGA-II(non-dominated sorting genetic algorithm II).Pre-optimized and optimized valve prototypes were fabricated via dip-molding and evaluated during pulsatile-flow tests and accelerated wear tests.The optimized design meets the ISO 5840 standards,with an effective orifice area of 2.019 cm^(2),a regurgitant fraction of 5.693%,and a transvalvular pressure gradient of 7.576 mmHg.Moreover,the optimized valve maintained its structural integrity and functionality over 14 million cycles of the accelerated wear test,whereas the unoptimized valve failed after two million cycles.These findings confirm that the FEM-based geometric optimization method enhances both the mechanical performance and durability of PHVs.
基金Funded by the National Natural Science Foundation of China(No.52208203)China Postdoctoral Science Foundation Funded Project(No.2023MD734209)+2 种基金Shaanxi Province Key Research and Development Program Project(No.2024GH-YBXM-03)Scientific Research Program Funded by Education Department of Shaanxi Provincial Government(No.23JP081)Innovation and Entrepreneurship Training Program for College Students(No.S202310703)。
文摘By using the phased characteristics summarizing method of the existing research on magnesium slag,this study investigates the hydration reaction,alkali activation reaction and CO_(2) mineralization reaction processes and mechanisms,and then explores its high-value utilization.The results show that physical and chemical activation can improve the mechanical properties of the gelled material system by increasing the crystal phase defects and surface energy and by reconstructing a new gelling system by depolymerizing glass.The CO_(2) mineralization reaction of magnesium slag can be used to construct a new gelling system for CaCO_(3) and calcium-modified silica gel.Magnesium slag can also be used to enhance the dry shrinkage and carbonation resistance of concrete owing to its expansibility and high alkali reserves.The mechanism and existence form of heavy metal ions in magnesium slag have been clarified.The study proposed a production system for magnesium slag and highlighted the potential research value in the field of wet carbonation to promote the application of magnesium slag.
文摘It is a good practice to change the site soil properties when dealing with inappropriate soils in geotechnical engineering,referred to as soil improvement.This study investigated the effects of epoxy resin LR202 stabilizer(5 wt%of soil as an optimum percentage)and glass fibers(0 wt%,0.4 wt%and 0.8 wt%of stabilized soil)as reinforcement on silty sand’s durability.For this purpose,the unconfined compressive strength test(12 tests),durability test(12 tests),ultrasonic pulse velocity(UPV)test(48 tests),and standard compactions test(5 tests)were performed.The results of this study showed that the addition of epoxy resin improves the durability of silty sand soil.The stabilized samples containing 5 wt%epoxy resin resisted 12 freeze-thaw cycles,and the sample behavior was enhanced by adding 0.4 wt%and 0.8 wt%fibers to the stabilized samples.Hence,the samples stabilized with epoxy resin exhibited acceptable behavior under freeze-thaw durability cycles.This indicates that epoxy resin stabilizer is appropriate in areas with possible frost and exhibits good behavior.The results of the UPV test showed that it could be used as a non-destructive test to control the durability of epoxy resin-stabilized soils.
基金supported by the following two grants:(i)Japan Society for the Promotion of Science(JSPS)KAKENHI Grant Number JP22H01581(i)National Research Counsil(NRC)of Sri Lanka Investigator Driven Grant Number 22-041.
文摘Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in irreversible changes and deterioration on its endurance.Numerous studies unveiled that hydrophobic surface protection could be an inexpensive and effective way of enhancing the durability of concrete.This research work aims to assess the feasibility of bio-cement posttreatment for facilitating hydrophobic surface protection,thus enhancing the performance and durability of concrete blocks.Enzyme induced carbonate precipitation(EICP)is one of the promising bio-cement methods.Concrete blocks casted in four different grades were subjected to EICP treatment with different treatment schemes and recipes of cementation media.The treated blocks were tested for water absorption,ultrasonic pulse velocity(UPV)measurements,unconfined compressive strength(UCS),thermal performance,and scanning electron microscopy(SEM).The results indicated that the concrete blocks subjected to EICP posttreatment showed over a 55%reduction in water absorption,a 15%higher UCS and a 6.7%higher UPV when compared with control blocks.The SEM analysis suggested that the EICP posttreatment could enhance the durability of concrete paving blocks by enabling a layer of calcite on the surface and by plugging the transport pore channels of the concrete.Although most of the posttreatment strategies investigated herein were found to be operative,a better response was seen in the posttreatment by spraying scheme with 0.5 mol/L cementation media(CM).With the successful demonstration,the EICP treatment prior to the use of concrete blocks can be recommended to the pavement construction industry.
基金supports from the National Key Research and Development Program of China(2022YFE03170002)the National Natural Science Foundation of China(52071286 and U2030208).
文摘The launch of International Thermonuclear Experimental Reactor project paves the way to wide adoption of DT fusion energy as future energy source.Efficient fuel cycle to minimize strategic tritium inventory proves crucial for commercially viable fusion technologies.ZrCo alloy is considered as a promising candidate for fast isotope handling.However,cycling degradation caused by hydrogen-induced disproportionation results in severe tritium trapping,thus impeding its practical application.Herein,an isostructural transition is successfully constructed with low hysterisis,ameliorated plateau flatness of pressure-composition isotherms and improved high-temperature durability for hydrogen trapping minimization.Specifically,the optimal Zr_(0.7)Hf_(0.15)Nb_(0.15)Co_(0.6)Cu_(0.15)Ni_(0.25) alloy adopts Hf-Nb and Cu-Ni as Zr and Co side doping elements,exhibiting substantial thermodynamic destabilization with nearly 90℃ reduction of delivery temperature,and significant kinetic promotion with a threefold lower energy barrier.More importantly,both hydrogen utilization and cycling retention of optimal alloy are increased by about twenty times compared with pristine alloy after 100 cycles at 500℃.Minimized disproportionation driving force from both isostructural transition and suppressed 8e hydrogen occupation realizes full potential of optimal alloy.This work demonstrates the effectiveness of combining isostructural transformation and high-temperature durability improvement to enhance the hydrogen utilization of ZrCo-based alloys and other hydrogen storage materials.
基金Funded by the Natural Science Foundation of Jiangsu Province(No.BK20220626)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX24_3174)Taizhou Science and Technology Support Programme(Social Development)Directive Project(No.TS202432)。
文摘The effects of various fly ash(FA)contents on the durability and mechanical properties of recycled fine aggregate high ductility cementitious composites(RFA-HDCC)prepared with recycled fine aggregates(RFA)to fully replace natural fine aggregates was investigated.The results indicated that a 50% FA content significantly increased the compressive strength of RFA-HDCC by 13.93%.However,a?further increase in FA content led to a drastic decrease.The increased fly ash content substantially reduced the flexural and tensile strength;however,it markedly increased the matrix strain capacity,resulting in a 53.73% increase in the peak strain when FA was raised to 70%.Regarding durability,the increase in FA content negatively affected the chloride ion permeability and carbonation resistance.However,the increase in FA content initially improved the frost resistance of RFA-HDCC,peaking at 50% FA and deteriorating at 60% and 70% FA content.
文摘In this paper,polyamide(PA)woven fabric was used as the base fabric,and polyurethane(PU)solution containing silica nanoparticles(PU@SiO_(2)NPs)was used as the coating solution to prepare composite tent fabric(PA/PU@SiO_(2)).The morphology,structure,and durability of the tent fabric under ultraviolet(UV)radiation,waterstained,or thermal conditions were investigated.The results show that compared with PA/PU fabric without SiO_(2)NPs,when the mass fraction of SiO_(2)NPs in PU coating is 5%,the air permeability of PA/PU@SiO_(2)fabric decreases from about 7.5 to 6.0 nm/s,while the reflectivity to UVvisible light is significantly improved.The surface wettability decreases,as indicated by the average water contact angle(WCA)on PA/PU@SiO_(2)remaining stable at 47°after 9 min.After thermal treatment,the PA/PU@SiO_(2)fabric shows superior mechanical stability.The degradation rate of the tensile strength is only 6.3%,approximately half that of the PA/PU fabric.Meanwhile,the elongation at break increases to 98.9%,compared to 61.8%for the PA/PU fabric.
基金The National Key Basic Research Program of China(973 Program)(No.2012CB026200)the Key Project of Chinese Ministry of Education(No.113029A)+1 种基金the National Key Technology R&D Program of China during the 12th Five Year Plan Period(No.2011BAB03B09)the Fundamental Research Funds for the Central Universities
文摘This paper presents an experimental study on the alkali-resistant properties of basalt fiber reinforced polymers （BFRP） bars under a typical concrete environment. BFRP bars were embedded in concrete and exposed to different aggressive environments, including tap water, saline solution and ambient temperature environments, to study the effects of the type of solution and relative humidity （RH） on the durability of BFRP. Meanwhile, BFRP bars were directly immersed in an alkaline solution for comparison. The acceleration factor describing the relationship between the alkaline solution immersion and the moisture-saturated concrete was also obtained. Aging was accelerated with a temperature of 60 ℃. The results show that the chloridion in the saline solution does not have any harmful effects on the degradation of the concrete-encased BFRP bars. Contact with an alkaline （high pH） concrete pore-water solution is the primary reason for the degradation of the BFRP bars. The degradation rate of concrete-encased BFRP bars is accelerated when a high temperature and a high humidity are present simultaneously. The degradation rate of the BFRP bars is relatively quick at the initial stage and slows down with exposure time. Results show that the degradation of 2.18 years in moisture-saturated concrete at 60 ℃corresponds to that of one year when directly immersed in an alkaline solution （other conditions remaining the same） for the BFRP bars analyzed.
文摘A method for a vehicle durability emission test using a robot driver insteadof human drivers on the chassis dynamometer is presented. The system architecture of vehicledurability emission test cell, the road load simulation strategy and the tele-monitoring systembased on Browser/Client structure are described. Furthermore, the construction of the robot driver,vehicle performance self-learning algorithm, multi-mode vehicle control model and vehicle speedtracking strategy based on fuzzy logic arealso discussed. Besides, the capability of controlparameters self-compensation on-line makes it possible to compensate the wear of vehicle componentsand the variety of clutch true bite point during the long term test. Experimental results show thattherobot driver can be applicable to a wide variety of vehicles and the obtained results stay withina tolerance band of ± 2 km/h. Moreover the robot driver is able to control tested vehicles withgood repeatability and consistency; therefore, this methodpresents a solution to eliminate theuncertainty of emission test results by human drivers and to ensure the accuracy and reliability ofemission test results.
基金The National Natural Science Foundation of China(No.50608013)Special Prophase Project on Basic Research of the National Department of Science and Technology(No.2004CCA04100)
文摘The test results of eight concrete beams reinforced with carbon fiber reinforced polymer （CFRP） sheets subjected to an aggressive environment under a sustained load are presented. The beams are 1 700 mm long with a rectangular cross-section of 120- mm width and 200-mm depth. The beams are precracked with a four-point flexural load, bonded CFRP sheets, and placed into wet-dry saline water（ NaCl） either in an unstressed state or loaded to about 30% or 60% of the initial ultimate load. The individual and coupled effects of wet-dry saline water and sustained bending stresses on the long term behaviour of concrete beams reinforced with the CFRP are investigated. The test results show that the coupled action of wet-dry saline water and sustained bending stresses appears to significantly affect the load capacity and the failure mode of beam strengthened with CFRP, mainly due to the degradation of the bond between CFRP and concrete. However, the stiffness is not affected by the coupled action of wet-dry cycles and a sustained load.
