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additives and permeability reducing admixtures having different action mechanisms on mechanical and durabilityperformance of cementitious systems

《结构与土木工程前沿（英文）》 2021年 第15卷 第5期   页码 1277-1291 doi: 10.1007/s11709-021-1752-2

摘要： In this paper, the effect of usage of the permeability reducing admixture (PRA) having different action mechanisms on hardened state properties of cementitious systems containing mineral additives is examined. For this aim, three commercial PRAs were used during investigation. The effective parameters in the first and third PRAs were air-entraining and high-rate air-entraining, respectively. The second one contained the insoluble calcium carbonate residue and had a small amount of the air-entraining property. Mortar mixes with binary and ternary cementitious systems were prepared by partially replacing cement with fly ash and metakaolin. The hardened state properties of mortar mixtures such as compressive strength, ultrasonic pulse velocity, water absorption, drying shrinkage and freeze–thaw resistance were investigated. The ternary cement-based mixture having both fly ash and metakaolin was selected as the most successful mineral-additive bearing mix in regard to hardened state properties. In this sense, PRA-B, with both insoluble residues and a small amount of air-entraining properties, showed the best performance among the mixtures containing PRA. The combined use of mineral additive and PRA had a more positive effect on the properties of the mixes.

关键词： cementitious system     mineral additive     permeability reducing admixture     mechanical properties     durability performance    

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A comprehensive assessment on the durability of gas diffusion electrode materials in PEM fuel cell stack

Arunkumar JAYAKUMAR

《能源前沿（英文）》 2019年 第13卷 第2期   页码 325-338 doi: 10.1007/s11708-019-0618-y

摘要： Polymer electrolyte membrane (PEM) fuel cell is the most promising among the various types of fuel cells. Though it has found its applications in numerous fields, the cost and durability are key barriers impeding the commercialization of PEM fuel cell stack. The crucial and expensive component involved in it is the gas diffusion electrode (GDE) and its degradation, which limits the performance and life of the fuel cell stack. A critical analysis and comprehensive understanding of the structural and functional properties of various materials involved in the GDE can help us to address the related durability and cost issues. This paper reviews the key GDE components, and in specific, the root causes influencing the durability. It also envisages the role of novel materials and provides a critical recommendation to improve the GDE durability.

关键词： PEM fuel cell     gas diffusion electrode(GDE)     gas diffusion layer(GDL)     membrane electrode assembly     durability     fuel cell catalyst    

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cathode with synergistic engineering of calcium-ion intercalation and polyaniline coating for high performance

《化学科学与工程前沿（英文）》 2023年 第17卷 第9期   页码 1244-1253 doi: 10.1007/s11705-022-2293-5

摘要： Vanadium oxides as cathode for zinc-ion batteries have attracted much attention because of their high theoretical capacity, flexible layered structure and abundant resources. However, cathodes are susceptible to the collapse of their layered structure and the dissolution of vanadium after repeated long cycles, which worsen their capacities and cycling stabilities. Herein, a synergistic engineering of calcium-ion intercalation and polyaniline coating was developed to achieve the superior electrochemical performance of vanadium pentoxide for zinc-ion batteries. The pre-intercalation of calcium-ion between vanadium pentoxide layers as pillars increase the crystal structure’s stability, while the polyaniline coating on the cathodes improves the conductivity and inhibits the dissolution of vanadium. This synergistic engineering enables that the battery system based-on the polyaniline coated calcium vanadate cathode to deliver a high capacity of 406.4 mAh·g−1 at 1 A·g−1, an ultralong cycle life over 6000 cycles at 10 A·g−1 with 93% capacity retention and high-rate capability. The vanadium oxide cathode with synergistic engineering of calcium-ion intercalation and polyaniline coating was verified to effectively improve the electrochemical performance of zinc-ion batteries.

关键词： zinc-ion battery     CaV8O20     polyaniline coating     synergistic engineering     high capacity     long durability    

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Cement mortar with enhanced flexural strength and durability-related properties using

Qing LIU, Renjun LIU, Qiao WANG, Rui LIANG, Zongjin LI, Guoxing SUN

《结构与土木工程前沿（英文）》 2021年 第15卷 第1期   页码 99-108 doi: 10.1007/s11709-021-0721-0

摘要： The low flexural strength and high brittleness of cementitious materials impair their service life in building structures. In this study, we developed a new polymer-modified mortar by polymerization of acrylamide (AM) monomers during the cement setting, which enhanced the flexural and durable performances of mortars. The mechanical properties, micro-and-pore structures, hydrated products, interactions between cement hydrates and polyacrylamide (PAM), and durability-related properties of the mortars were investigated comprehensively. Mortars with 5% PAM exhibited the best performance in terms of flexural strength among all the mixtures. The mechanical strength of cement pastes modified by polymerization of AM monomers was significantly superior to those modified by PAM. The chemical interactions between the polymer molecules and cement hydrates together with the formation of polymer films glued the cement hydrates and polymers and resulted in an interpenetrating network structure, which strengthened the flexural strength. Reductions in porosity and calcium hydroxide content and improvement in capillary water absorption were achieved with the addition of PAM. Finally, the chloride resistance was significantly enhanced with the incorporation of PAM.

关键词： acrylamide     in situ polymerization     interaction     porosity     durability    

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Sustainability of steel structures: towards an integrated approach to life-time engineering design

Raffaele LANDOLFO, Lucrezia CASCINI, Francesco PORTIOLI

《结构与土木工程前沿（英文）》 2011年 第5卷 第3期   页码 304-314 doi: 10.1007/s01709-011-0123-9

摘要： Nowadays, the construction sector is more and more oriented toward the promotion of sustainability in all its activities. The goal to achieve is the optimization of performances, over the whole life-cycle, with respect to environmental, economic and social requirements. According to the latest advances, the concept of sustainability applied to constructions covers a number of branches such as life-cycle costing, ecology, durability and even structural design. Several procedures and design tools have been implemented in the framework of international research. Indeed the current trend in civil engineering research is moving towards life-time engineering, with the aim to implement integrated methodologies to consider as a whole all the sustainability requirements according to time-dependent multi-performance-based design approaches. Following a general introduction of the concept of sustainability applied to constructions, this paper presents an overview of life-time engineering methodologies according to the current state-of-the-art. In particular the methods currently received by International Standards are discussed. A special focus is devoted to the durability design of metal structures with respect to the degradation phenomena able to impair the structural capacity over time. Finally a proposal towards an integrated approach to life-time engineering design of steel structures and needs for further advances are presented.

关键词： sustainability     life-time engineering     performance based design     durability     metal structures    

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Fresh and hardened properties of high-performance fiber-reinforced concrete containing fly ash and rice

Nguyen-Trong HO; Viet Quoc DANG; Minh-Hieu NGUYEN; Chao-Lung HWANG; Trong-Phuoc HUYNH

《结构与土木工程前沿（英文）》 2022年 第16卷 第12期   页码 1621-1632 doi: 10.1007/s11709-022-0884-3

摘要： Although fibers are used only infrequently as an additive in concrete in the construction industry, fiber-enhanced concrete is known to provide a wide range of advantages over conventional concrete. The main objective of this study was to investigate the influences of fiber type and content on the mechanical properties and durability of high-performance fiber-reinforced concrete (HPFRC) designed using a novel densified mixture design algorithm with fly ash and rice husk ash. Three types of fiber, including polypropylene (PP) fiber, steel fiber (SF), and hybrid fiber (HF), were considered. Based on the results, the inclusion of fibers decreased HPFRC flowability, regardless of fiber type. Although the compressive strength of HPFRC with 1.6% PP fiber content was 11.2% below that of the reference HPFRC specimen at 91 d of curing age, the 91-d compressive strengths of both SF and HF-enhanced HPFRC specimens were significantly better than that of the reference HPFRC specimen. Furthermore, the HPFRC specimens incorporating SF and HF both exhibited better splitting tensile and flexural strengths as well as less drying shrinkage than the HPFRC specimens incorporating PP fiber. However, the fiber-enhanced specimens, especially those with added SF, registered less surface electrical resistivity and greater vulnerability to chloride ion penetration than the reference HPFRC specimen.

关键词： high-performance fiber-reinforced concrete     fly ash     rice husk ash     durability     mechanical strength    

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高性能多功能水泥基复合材料 Article

Victor C. Li

《工程（英文）》 2019年 第5卷 第2期   页码 250-260 doi: 10.1016/j.eng.2018.11.031

摘要：

混凝土是一种不断发展的材料，甚至高性能混凝土的定义也正随着时间的推移而发生变化。本文所说的混凝土材料的高性能特性是指那些直接影响我们生活质量的民用基础设施的理想耐久性、回弹性和可持续性的特性。这些特性包括拉伸延展性、自体裂缝宽度控制和材料的“绿色”环保性。此外，智能功能应旨在通过响应结构周围环境的变化来提高基础设施的耐久性、回弹性和可持续性以实现其理想功能，从而使材料的行为方式更类似于某些生物材料。本文基于工程水泥基复合材料（ECC）的最新研究进展，提出可以设计出具有高性能兼智能多功能性的混凝土材料，并且其具有满足 21 世纪民用基础设施预期需求的潜力。本文重点介绍了 ECC 的相关特性以及未来研究的方向。

关键词： 高性能混凝土     多功能     智能     水泥基复合材料     耐久性     回弹性     可持续性     基础设施    

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Experimental investigation on freeze−thaw durability of polymer concrete

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 1038-1046 doi: 10.1007/s11709-021-0748-2

摘要： Assessing the durability of concrete is of prime importance to provide an adequate service life and reduce the repairing cost of structures. Freeze–thaw is one such test that indicates the ability of concrete to last a long time without a significant loss in its performance. In this study, the freeze–thaw resistance of polymer concrete containing different polymer contents was explored and compared to various conventional cement concretes. Concretes’ fresh and hardened properties were assessed for their workability, air content, and compressive strength. The mass loss, length change, dynamic modulus of elasticity, and residual compressive strength were determined for all types of concretes subjected to freeze–thaw cycles according to ASTM C666-procedure A. Results showed that polymer concrete (PC) specimens prepared with higher dosages of polymer contents possessed better freeze–thaw durability compared to other specimens. This high durability performance of PCs is mainly due to their impermeable microstructures, absence of water in their structure, and the high bond strength between aggregates and a polymer binder. It is also indicated that the performance of high-strength concrete containing air-entraining admixture is comparable with PC having optimum polymer content in terms of residual compressive strength, dynamic modulus of elasticity, mass loss, and length change.

关键词： durability test     freeze-thaw resistance     polymer concrete     residual compressive strength     ASTM C666-15    

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Experimental study on flexural behavior of ECC/RC composite beams with U-shaped ECC permanent formwork

Zhi QIAO, Zuanfeng PAN, Weichen XUE, Shaoping MENG

《结构与土木工程前沿（英文）》 2019年 第13卷 第5期   页码 1271-1287 doi: 10.1007/s11709-019-0556-0

摘要： To enhance the durability of a reinforced concrete structure, engineered cementitious composite (ECC), which exhibits high tensile ductility and good crack control ability, is considered a promising alternative to conventional concrete. However, broad application of ECC is hindered by its high cost. This paper presents a new means to address this issue by introducing a composite beam with a U-shaped ECC permanent formwork and infill concrete. The flexural performance of the ECC/RC composite beam has been investigated experimentally with eight specimens. According to the test results, the failure of a composite beam with a U-shaped ECC formwork is initiated by the crushing of compressive concrete rather than debonding, even if the surface between the ECC and the concrete is smooth as-finished. Under the same reinforcement configurations, ECC/RC composite beams exhibit increases in flexural performance in terms of ductility, load-carrying capacity, and damage tolerance compared with the counterpart ordinary RC beam. Furthermore, a theoretical model based on the strip method is proposed to predict the moment-curvature responses of ECC/RC composite beams, and a simplified method based on the equivalent rectangular stress distribution approach has also evolved. The theoretical results are found to be in good agreement with the test data.

关键词： engineered cementitious composite (ECC)     durability     ECC/RC composite beam     permanent formwork     flexural performance     theoretical method    

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渤海海峡隧道支护结构耐久性分析

吴永胜,万飞,谭忠盛

《中国工程科学》 2013年 第15卷 第12期   页码 67-72

摘要：

通过对海底隧道结构耐久性影响因素进行分析，并根据工程试验研究成果及设计施工技术经验，提出了渤海海峡隧道初期支护和二次衬砌结构耐久性的提高措施。对已成功修建的海底隧道耐久性设计参数进行分析整理，结合渤海海峡隧道的实际情况，采用工程类比法提出了渤海海峡隧道的耐久性设计参数，为渤海海峡隧道100年使用年限提供了有力的保障。

关键词： 海底隧道     支护结构     耐久性     设计参数    

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基于PFM的B级钢侧架耐久性分析

李伟,李强,王平

《中国工程科学》 2011年 第13卷 第1期   页码 56-61

摘要：

基于概率断裂力学对B级钢货车侧架的圆角细节进行了模拟耐久性试验研究，提出了一种新的通用当量初始缺陷尺寸分布的计算方法，建立了裂纹超越概率模型，从存活概率P, 应力水平σ, 裂纹形成时间t和经济维修极限ae 4个角度评估了结构的损伤度, 并结合实测的应力谱预测了其经济寿命。结果表明，裂纹萌生时间能很好地服从三参数Weibull分布，求得的通用EIFS分布参数通过了K—S检验，拟合效果很好。裂纹超越概率模型可以对结构产生的耐久性损伤进行定量度量，预测的经济寿命随裂纹穿越概率的增加呈现增长的趋势，验证了新的计算方法和概率模型的合理有效性。

关键词： 耐久性     疲劳     B级钢     裂纹    

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A new systematic firefly algorithm for forecasting the durability of reinforced recycled aggregate concrete

Wafaa Mohamed SHABAN; Khalid ELBAZ; Mohamed AMIN; Ayat gamal ASHOUR

《结构与土木工程前沿（英文）》 2022年 第16卷 第3期   页码 329-346 doi: 10.1007/s11709-022-0801-9

摘要： This study presents a new systematic algorithm to optimize the durability of reinforced recycled aggregate concrete. The proposed algorithm integrates machine learning with a new version of the firefly algorithm called chaotic based firefly algorithm (CFA) to evolve a rational and efficient predictive model. The CFA optimizer is augmented with chaotic maps and Lévy flight to improve the firefly performance in forecasting the chloride penetrability of strengthened recycled aggregate concrete (RAC). A comprehensive and credible database of distinctive chloride migration coefficient results is used to establish the developed algorithm. A dataset composite of nine effective parameters, including concrete components and fundamental characteristics of recycled aggregate (RA), is used as input to predict the migration coefficient of strengthened RAC as output. k-fold cross validation algorithm is utilized to validate the hybrid algorithm. Three numerical benchmark analyses are applied to prove the superiority and applicability of the CFA algorithm in predicting chloride penetrability. Results show that the developed CFA approach significantly outperforms the firefly algorithm on almost tested functions and demonstrates powerful prediction. In addition, the proposed strategy can be an active tool to recognize the contradictions in the experimental results and can be especially beneficial for assessing the chloride resistance of RAC.

关键词： chloride penetrability     recycled aggregate concrete     machine learning     concrete components     durability    

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Accelerated life-time test of MEA durability under vehicle operating conditions in PEM fuel cell

Tian TIAN, Jianjun TANG, Wei GUO, Mu PAN

《能源前沿（英文）》 2017年 第11卷 第3期   页码 326-333 doi: 10.1007/s11708-017-0489-z

摘要： In this paper, a novel accelerated test method was proposed to analyze the durability of MEA, considering the actual operation of the fuel cell vehicle. The proposed method includes 7 working conditions: open circuit voltage (OCV), idling, rated output, overload, idling-rated cycle, idling-overload cycle, and OCV-idling cycle. The experimental results indicate that the proposed method can effectively destroy the MEA in a short time (165 h). Moreover, the degradation mechanism of MEA was analyzed by measuring the polarization curve, CV, SEM and TEM. This paper may provide a new research direction for improving the durability of fuel cell.

关键词： polymer electrolyte membrane fuel cell     accelerated life-time test     load cycling test     durability    

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Long-term durability of onshore coated concrete —chloride ion and carbonation effects

Seyedhamed SADATI,Mehdi K. MORADLLO,Mohammad SHEKARCHI

《结构与土木工程前沿（英文）》 2016年 第10卷 第2期   页码 150-161 doi: 10.1007/s11709-016-0341-2

摘要： Enhancing service life of reinforced concrete (RC) structures located in marine environments is an issue of great interest for design engineers. The present research addresses the effect of surface coatings on service life of onshore RC structures. Long-term performance of concrete samples up to 88 months of exposure at natural marine environment was investigated. Two onshore exposure conditions, including soil and atmosphere and different types of concrete coatings were studied. Carbonation rates of up to 0.5 and 1.5 mm/year were observed at the first 88 months of exposure for soil and atmospheric samples, respectively. Surface chloride ion build-up and variation in chloride ion diffusion were monitored with respect to time, and service life was estimated. Based on the obtained results it is proposed to use the aliphatic acrylic and polyurethane coatings for enhancing the service life of concrete structures in the investigated exposure conditions.

关键词： carbonation     chloride ion     corrosion     service life     surface coating    

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Enhancing compressive strength and durability of self-compacting concrete modified with controlled-burnt

《结构与土木工程前沿（英文）》 2022年 第16卷 第2期   页码 161-174 doi: 10.1007/s11709-021-0796-7

摘要： In sugar industries, the growing amount of sugarcane bagasse ash (SBA), a byproduct released after burning bagasse for producing electricity, is currently causing environmental pollution. The residual ash displays a pozzolanic potential; and hence, it has potential as a cement addictive. This study focuses on enhancing suitability of SBA through incorporating ground blast furnace slag (BFS) in manufacturing self-compacting concretes (SCCs). For this purpose, SBA was processed by burning at 700 °C for 1 h, before being ground to the cement fineness of 4010 cm2/g. SCC mixtures were prepared by changing the proportions of SBA and BFS (i.e., 10%, 20%, and 30%) in blended systems; and their performance was investigated. Test results showed that the presence of amorphous silica was detected for the processed SBA, revealing that the strength activity index was above 80%. The compressive strength of SCC containing SBA (without BFS) could reach 98%−127% of that of the control; combination of SBA and 30% BFS gets a similar strength to the control after 28 d. Regarding durability, the 10%SBA + 30%BFS mix exhibited the lowest risk of corrosion. Moreover, the joint use of SBA and BFS enhanced significantly the SCC’s sulfate resistance. Finally, a hyperbolic formula for interpolating the compressive strength of the SBA-based SCC was proposed and validated with error range estimated within ±10%.

关键词： sugarcane bagasse ash     self-compacting concrete     compressive strength     sulfate resistance     water absorption     strength formula    

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标题 作者 时间 类型 操作

additives and permeability reducing admixtures having different action mechanisms on mechanical and durabilityperformance of cementitious systems

期刊论文

A comprehensive assessment on the durability of gas diffusion electrode materials in PEM fuel cell stack

Arunkumar JAYAKUMAR

期刊论文

cathode with synergistic engineering of calcium-ion intercalation and polyaniline coating for high performance

期刊论文

Cement mortar with enhanced flexural strength and durability-related properties using

Qing LIU, Renjun LIU, Qiao WANG, Rui LIANG, Zongjin LI, Guoxing SUN

期刊论文

Sustainability of steel structures: towards an integrated approach to life-time engineering design

Raffaele LANDOLFO, Lucrezia CASCINI, Francesco PORTIOLI

期刊论文

Fresh and hardened properties of high-performance fiber-reinforced concrete containing fly ash and rice

Nguyen-Trong HO; Viet Quoc DANG; Minh-Hieu NGUYEN; Chao-Lung HWANG; Trong-Phuoc HUYNH

期刊论文

高性能多功能水泥基复合材料

Victor C. Li

期刊论文

Experimental investigation on freeze−thaw durability of polymer concrete

期刊论文

Experimental study on flexural behavior of ECC/RC composite beams with U-shaped ECC permanent formwork

Zhi QIAO, Zuanfeng PAN, Weichen XUE, Shaoping MENG

期刊论文

渤海海峡隧道支护结构耐久性分析

吴永胜,万飞,谭忠盛

期刊论文

基于PFM的B级钢侧架耐久性分析

李伟,李强,王平

期刊论文

A new systematic firefly algorithm for forecasting the durability of reinforced recycled aggregate concrete

Wafaa Mohamed SHABAN; Khalid ELBAZ; Mohamed AMIN; Ayat gamal ASHOUR

期刊论文

Accelerated life-time test of MEA durability under vehicle operating conditions in PEM fuel cell

Tian TIAN, Jianjun TANG, Wei GUO, Mu PAN

期刊论文

Long-term durability of onshore coated concrete —chloride ion and carbonation effects

Seyedhamed SADATI,Mehdi K. MORADLLO,Mohammad SHEKARCHI

期刊论文

Enhancing compressive strength and durability of self-compacting concrete modified with controlled-burnt

期刊论文