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Performance of steel bridge deck pavement structure with ultra high performance concrete based on resin

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 895-904 doi: 10.1007/s11709-021-0759-z

摘要： This research investigated a pavement system on steel bridge decks that use epoxy resin (EP) bonded ultra-high performance concrete (UHPC). Through FEM analysis and static and dynamic bending fatigue tests of the composite structure, the influences of the interface of the pavement layer, reinforcement, and different paving materials on the structural performance were compared and analyzed. The results show that the resin bonded UHPC pavement structure can reduce the weld strain in the steel plate by about 32% and the relative deflection between ribs by about 52% under standard axial load conditions compared to traditional pavements. The EP bonding layer can nearly double the drawing strength of the pavement interface from 1.3 MPa, and improve the bending resistance of the UHPC structure on steel bridge decks by about 50%; the bending resistance of reinforced UHPC structures is twice that of unreinforced UHPC structure, and the dynamic deflection of the UHPC pavement structure increases exponentially with increasing fatigue load. The fatigue life is about 1.2 × 107 cycles under a fixed force of 9 kN and a dynamic deflection of 0.35 mm, which meets the requirements for fatigue performance of pavements on steel bridge decks under traffic conditions of large flow and heavy load.

关键词： steel bridge deck pavement     ultra-high-performance concrete     epoxy resin     composite structure     bending fatigue performance    

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Micromixing performance of the teethed high shear mixer under semi-batch operation

《化学科学与工程前沿（英文）》 2022年 第16卷 第4期   页码 546-559 doi: 10.1007/s11705-021-2069-3

摘要： Semi-batch operated reaction processes are necessary for some competitive reaction systems to achieve a desirable process selectivity and productivity of fine chemical products. Herein the structural and operating parameters of the teethed high shear mixers were adjusted to study the micromixing performance in the semi-batch operated system, using the Villermaux/Dushman reaction system. The results indicate that the rising of the rotor speed and the number of rotor teeth, the decrease of the width of the shear gap and the radial distance between the feed position and the inner wall of stator can enhance the micromixing level and lead to the decrease of the segregation index. Additionally, computational fluid dynamics calculations were carried out to disclose the evolution of the flow pattern and turbulent energy dissipation rate of the semi-batch operated high shear mixer. Furthermore, the correlation was established with a mean relative error of 8.05% and R2 of 0.955 to fit the segregation index and the parameters studied in this work, which can provide valuable guidance on the design and optimization of the semi-batch operated high shear mixers in practical applications.

关键词： high shear mixer     semi-batch operation     micromixing performance     Villermaux/Dushman system     segregation index    

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Experimental research on cyclone performance at high temperature

LI Wenqi, CHEN Jianyi

《机械工程前沿（英文）》 2007年 第2卷 第3期   页码 310-317 doi: 10.1007/s11465-007-0055-1

摘要： To predict the influence of operating temperatures on cyclone performance, an experimental investigation was conducted on particle separation in a reverse flow, tangential volute-inlet cyclone separator with a diameter of 300 mm and with air heated up to 973 K. The test powder silica has a mass median diameter of 10 um, while inlet velocity range was 12-36 m/s. Both the separation efficiency and pressure drop of the cyclone were measured as a function of the inlet velocity and operating temperature. At the same inlet velocity, both the separation efficiency and pressure drop decrease with increasing temperature. In addition, optimum inlet velocity, at which the cyclone has its highest separation efficiency, tends to increase with a rise in temperature. An analysis on our own data and published results has shown that the fractional efficiency of a cyclone is a definite function of dimensionless numbers such as the Stokes number, the Reynolds number, the Froude number, dimensionless cyclone inlet area, and dimensionless outlet diameter. A nondimensional experimental correlation of the cyclone performance, including the influence of temperature, was obtained on the basis of our own previous work. The prediction of the influence of temperature on separation efficiencies and pressure drops is in fairly good agreement with experimental results.

关键词： diameter     definite function     nondimensional experimental     cyclone performance     influence    

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Recovery and reuse of floc sludge for high-performance capacitors

《环境科学与工程前沿（英文）》 2022年 第16卷 第6期 doi: 10.1007/s11783-021-1512-5

摘要：

• The feasibility of facile fabrication of capacitor from floc sludge is discussed.

关键词： Floc sludge     Porous carbon electrode     Energy storage performance     Supercapacitors    

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Effect of cavity defect on the triaxial mechanical properties of high-performance concrete

Yanbin ZHANG; Zhe WANG; Mingyu FENG

《结构与土木工程前沿（英文）》 2022年 第16卷 第5期   页码 600-614 doi: 10.1007/s11709-022-0821-5

摘要： The stress concentration of pipe structure or cavity defect has a great effect on the mechanical properties of the high-performance concrete (HPC) members in deep underground locations. However, the behaviour of HPC with cavities under triaxial compression is not understood, especially when pressurized liquid flows into the fractures from the cavity. This study aims to investigate the effect of the cavity and the confining pressure on the failure mechanisms, strengths, and deformation properties of HPC with a new experimental scheme. In this experiment, the pressurized liquid can only contact the surface of the sample in the cavity, while the other surfaces are isolated from the pressurized liquid. To further explore the effect of the cavity, the same experiments are also conducted on sealed and unsealed intact samples without a cavity. The failure modes and stress-strain curves of all types of the samples are presented. Under various confining pressures, all the samples with a cavity suffer shear failure, and there are always secondary tensile fractures initiating from the cavity sidewall. Additionally, it can be determined from the failure modes and the stress-strain curves that the shear fractures result from the sidewall failure. Based on the different effects of the cavity on the lateral deformations in different directions, the initiation of the sidewall fracture is well predicted. The experimental results show that both the increase of the confining pressure and the decrease of the cavity size are conducive to the initiation of sidewall fracture. Moreover, the cavity weakens the strength of the sample, and this study gives a modified Power-law criterion in which the cavity size is added as an impact factor to predict the strength of the sample.

关键词： high-performance concrete     cavity     conventional triaxial compression     pressurized liquid     modified power-law criterion    

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Flexural and longitudinal shear performance of precast lightweight steel–ultra-high performance concrete

《结构与土木工程前沿（英文）》 2023年 第17卷 第5期   页码 704-721 doi: 10.1007/s11709-023-0941-6

摘要： In this study, the flexural and longitudinal shear performances of two types of precast lightweight steel–ultra-high performance concrete (UHPC) composite beams are investigated, where a cluster UHPC slab (CUS) and a normal UHPC slab (NUS) are connected to a steel beam using headed studs through discontinuous shear pockets and full-length shear pockets, respectively. Results show that the longitudinal shear force of the CUS is greater than that of the NUS, whereas the interfacial slip of the former is smaller. Owing to its better integrity, the CUS exhibits greater flexural stiffness and a higher ultimate bearing capacity than the NUS. To further optimize the design parameters of the CUS, a parametric study is conducted to investigate their effects on the flexural and longitudinal shear performances. The square shear pocket is shown to be more applicable for the CUS, as the optimal spacing between two shear pockets is 650 mm. Moreover, a design method for transverse reinforcement is proposed; the transverse reinforcement is used to withstand the splitting force caused by studs in the shear pocket and prevent the UHPC slab from cracking. According to calculation results, the transverse reinforcement can be canceled when the compressive strength of UHPC is 150 MPa and the volume fraction of steel fiber exceeds 2.0%.

关键词： precast steel–UHPC composite beam     flexural performance     longitudinal shear performance     parametric study     transverse reinforcement ratio    

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Development and road performance of clear asphalt with high transparency and adhesion

《结构与土木工程前沿（英文）》 2023年 第17卷 第2期   页码 238-255 doi: 10.1007/s11709-022-0898-x

摘要： Clear asphalt (CA) currently used in light-colored asphalt mixtures (LCAM) exhibits poor transparency and adhesion. Therefore, a highly transparent CA (HCA) modified using a silane coupling agent (KH550) was prepared. Furthermore, LCAM was prepared by mixing CA and limestone aggregates. The properties of the HCA and ordinary CA (OCA) were characterized using conventional asphalt tests, optical tests, pull-off tests, ultraviolet aging tests, dynamic shear rheometry, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. Whereas Marshall, moisture resistance, wheel tracking, trabecular bending, and British pendulum tests were employed for the LCAM. The transmittance and spectral reflectance of the HCA were 123.30 and 3.74 times greater than those of the OCA, respectively. The complex modulus and viscosity-aging index of the HCA were 48% and 53% less than those of the OCA, respectively. After modification with KH550, the Marshall stability ratio, tensile strength ratio, and flexural strain of the HCA-prepared LCAM increased by 12.92%, 25.06%, and 23.90%, respectively. However, the rutting resistance of the HCA-prepared LCAM was 14.3% less than that of the OCA-prepared LCAM. The comprehensive performances of the HCA and HCA-prepared LCAM were 49.2% and 10.3% greater than those of the OCA and OCA-prepared LCAM, respectively, indicating a high application value in the future.

关键词： light-colored asphalt pavement     orthogonal test     road performance     spectral reflectance     silane-coupling agent    

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Construction of interfacial dynamic bonds for high performance lignin/polymer biocomposites

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1372-1388 doi: 10.1007/s11705-023-2302-3

摘要： Lignin is the largest natural aromatic biopolymer, but usually treated as industrial biomass waste. The development of lignin/polymer biocomposites can promote the high value utilization of lignin and the greening of polymers. However, the weak interfacial interaction between industrial lignin and polymer induces poor compatibility and serious agglomeration in polymer owing to the strong intermolecular force of lignin. As such, it is extremely difficult to prepare high performance lignin/polymer biocomposites. Recently, we proposed the strategy of in situ construction of interfacial dynamic bonds in lignin/polymer composites. By taking advantage of the abundant oxygen-containing polar groups of lignin, we inserted dynamic bonding connection such as hydrogen bonds and coordination bonds into the interphase between lignin and the polymer matrix to improve the interfacial interactions. Meanwhile, the natural amphiphilic structure characteristics of lignin were utilized to construct the hierarchical nanophase separation structure in lignin/polymer composites. The persistent problems of poor dispersity and interfacial compatibility of lignin in the polymer matrix were effectively solved. The lignin-modified polymer composites achieved simultaneously enhanced strength and toughness. This concise review systematically summarized the recent research progress of our group toward building high-performance lignin/polymer biocomposites through the design of interfacial dynamic bonds (hydrogen bonds, coordination bonds, and dynamic covalent bonds) between lignin and different polymer systems (polar plastics, rubber, polyurethane, hydrogels, and other polymers). Finally, the future development direction, main challenges, and potential solutions of lignin application in polymers were presented.

关键词： lignin     polymer     interfacial dynamic bonds    

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Shear behavior of ultra-high-performance concrete beams prestressed with external carbon fiber-reinforced

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1426-1440 doi: 10.1007/s11709-021-0783-z

摘要： The ultra-high-performance concrete (UHPC) and fiber-reinforced polymer (FRP) are well-accepted high-performance materials in the field of civil engineering. The combination of these advanced materials could contribute to improvement of structural performance and corrosion resistance. Unfortunately, only limited studies are available for shear behavior of UHPC beams reinforced with FRP bars, and few suggestions exist for prediction methods for shear capacity. This paper presents an experimental investigation on the shear behavior of UHPC beams reinforced with glass FRP (GFRP) and prestressed with external carbon FRP (CFRP) tendons. The failure mode of all specimens with various shear span to depth ratios from 1.7 to 4.5 was diagonal tension failure. The shear span to depth ratio had a significant influence on the shear capacity, and the effective prestressing stress affected the crack propagation. The experimental results were then applied to evaluate the equations given in different codes/recommendations for FRP-reinforced concrete structures or UHPC structures. The comparison results indicate that NF P 18-710 and JSCE CES82 could appropriately estimate shear capacity of the slender specimens with a shear span to depth ratio of 4.5. Further, a new shear design equation was proposed to take into account the effect of the shear span to depth ratio and the steel fiber content on shear capacity.

关键词： beam     external prestressing     ultra-high-performance concrete     fiber-reinforced polymers     shear behavior     design equation    

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Fast determination of tobramycin by reversed-phase ion-pair high performance liquid chromatography with

Liang ZHU, Jingkang WANG

《化学科学与工程前沿（英文）》 2013年 第7卷 第3期   页码 322-328 doi: 10.1007/s11705-013-1348-z

摘要： A simple and direct method without a derivation step for routine analysis of tobramycin has been developed. This method used reversed-phase ion-pair high performance liquid chromatography (HPLC) with a refractive index (RI) detector and a C18 column which is stable at pH above 1.00. The presence of 4.50 mg·mL trifluoroacetic acid (TFA) in the mobile phase improved the protonation of tobramycin and the formation of ion-pairs, and thus reduced its hydrophility. This unique separation–detection combination showed good linearity with correlation coefficients 0.9996 in the concentration range of 0.25–2.50 mg·mL . The quantitation limit and detection limit were determined to be 0.23 mg·mL and 0.071 mg·mL , respectively. Tobramycin was recovered in 98.00%, 98.84% and 99.64% for tobramycin solutions at concentrations of 2.25 mg·mL , 1.50 mg·mL and 0.75 mg·mL , respectively. The relative standard deviations for six spiked samples ranged from 0.20% to 2.40%, indicating a good reproducibility of this method.

关键词： tobramycin     aminoglycoside     refractive index detector     high-performance liquid chromatography     ion-pairing    

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Behavior and strength of headed stud shear connectors in ultra-high performance concrete of composite

Jianan QI, Yuqing HU, Jingquan WANG, Wenchao LI

《结构与土木工程前沿（英文）》 2019年 第13卷 第5期   页码 1138-1149 doi: 10.1007/s11709-019-0542-6

摘要： This study presents an experimental and numerical investigation on the static behavior of headed stud shear connectors in ultra-high performance concrete (UHPC) of composite bridges. Four push-out specimens were tested. It was found that no cracking, crushing or splitting was observed on the concrete slab, indicating that UHPC slab exhibited good performance and could resist the high force transferred from the headed studs. The numerical and experimental results indicated that the shear capacity is supposed to be composed of two parts stud shank shear contribution and concrete wedge block shear contribution. The stiffness increment of a stud in UHPC was at least 60% higher than that in normal strength concrete. Even if the stud height was reduced from 6 to 2 , there was no reduction in the shear strength of a stud. Short stud shear connectors with an aspect ratio as small as 2 could develop full strength in UHPC slabs. An empirical load-slip equation taking into account stud diameter was proposed to predict the load-slip response of a stud. The reliability and accuracy of the proposed load-slip equation was verified by the experimental and numerical load-slip curves.

关键词： ultra-high performance concrete     studs     shear strength     FE analysis     push-out test    

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Experimental investigations of internal energy dissipation during fracture of fiber-reinforced ultra-high-performance

Eric N. LANDIS, Roman KRAVCHUK, Dmitry LOSHKOV

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 190-200 doi: 10.1007/s11709-018-0487-1

摘要： Split-cylinder fracture of fiber-reinforced ultra-high-performance concrete (UHPC) was examined using two complementary techniques: X-ray computed tomography (CT) and acoustic emission (AE). Fifty-mm-diameter specimens of two different fiber types were scanned both before and after load testing. From the CT images, fiber orientation was evaluated to establish optimum and pessimum specimen orientations, at which fibers would have maximum and minimum effect, respectively. As expected, fiber orientation affected both the peak load and the toughness of the specimen, with the optimum toughness being between 20% and 30% higher than the pessimum. Cumulative AE energy was also affected commensurately. Posttest CT scans of the specimens were used to measure internal damage. Damage was quantified in terms of internal energy dissipation due to both matrix cracking and fiber pullout by using calibration measurements for each. The results showed that fiber pullout was the dominant energy dissipation mechanism; however, the sum of the internal energy dissipation measured amounted to only 60% of the total energy dissipated by the specimens as measured by the net work of load. It is postulated that localized compaction of the UHPC matrix as well as internal friction between fractured fragments makes up the balance of internal energy dissipation.

关键词： ultra-high-performance concrete     concrete fracture     X-ray computed tomography     acoustic emission    

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Fabrication of high-performance pervaporation composite membrane for alkaline wastewater reclamation

《化学科学与工程前沿（英文）》 2022年 第16卷 第5期   页码 709-719 doi: 10.1007/s11705-021-2078-2

摘要： Pervaporation desalination has a unique advantage to recycle concentrated salt solutions. The merit can be applied to treat alkaline wastewater if the membrane has superior alkali-resistance. In this paper, we used polyethylene microfiltration membrane as the substrate and deposited a glutaraldehyde crosslinked sodium carboxymethylcellulose layer by spray-coating. Pervaporation flux of the composite membrane reached 35€±€2 kg·m–2·h–1 with a sodium chloride rejection of 99.9%€±€0.1% when separating a 3.5 wt-% sodium chloride solution at 70 °C. The desalination performance was stable after soaking the membrane in a 20 wt-% NaOH solution at room temperature for 9 d and in a 10 wt-% NaOH solution at 60 °C for 80 h. Moreover, the membrane was stable in 4 wt-% sulfuric acid and a 500 mg·L−1 sodium hypochlorite solution. In a process of concentrating a NaOH solution from 5 to 10 wt-% at 60 °C, an average water flux of 23 kg·m–2·h–1 with a NaOH rejection over 99.98% was obtained.

关键词： pervaporation     alkaline solution concentration     polyethylene membrane     acid resistance     chlorine tolerance    

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Freshwater algae chemotaxonomy by high-performance liquid chromatographic (HPLC) analysis

Yansong HOU, Wei LIANG, Liping ZHANG, Shuiping CHENG, Feng HE, Zhenbin WU

《环境科学与工程前沿（英文）》 2011年 第5卷 第1期   页码 84-91 doi: 10.1007/s11783-010-0283-1

摘要： The study of community composition of algae is essential for understanding the structure and dynamics of the aquatic ecosystem and for evaluating the eutrophic level of the water body. A high-performance liquid chromatographic (HPLC) method based on a reverse-phase C nonpolar column was developed for the main algal taxa, which includes cyanophytes, bacillariophytes, euglenophytes, dinophytes, and chlorophytes. Based on the elution order using HPLC, 19 pigments were identified, and they were chlorophyllide , 19′-butanoyloxyfucoxanthin, chlorophyll + , phephorbides , peridinin, methyl-chlorophyllide , fucoxanthin, neoxanthin, violaxanthin, myxoxanthophyll, diadinoxanthin, diatoxanthin, lutein, zeaxanthin, chlorophyll allomer, chlorophyll , chlorophyll allomer, chlorophyll , and β,β-carotene. A comparison study of cell microscopic counts and accessory pigment analysis indicated that HPLC analysis could be a useful tool for monitoring phytoplankton communities and their abundance.

关键词： high-performance liquid chromatographic (HPLC)     algae     pigment     chemotaxonomy    

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Fabricating sustainable lignin-derived porous carbon as electrode for high-performance supercapacitors

《化学科学与工程前沿（英文）》 2023年 第17卷 第8期   页码 1065-1074 doi: 10.1007/s11705-023-2313-0

摘要： Lignocellulosic biomass such as plants and agricultural waste are ideal to tackle the current energy crisis and energy-related environmental issues. Carbon-rich lignin is abundant in lignocellulosic biomass, whose high-value transformation and utilization has been the most urgent problem to be solved. Herein, we propose a method for the preparation of porous carbon from lignin employing an H3PO4-assisted hydrothermal method. We characterize the as-prepared lignin-derived porous carbon and investigate its potential for energy storage. After assisted hydrothermal treatment followed by carbonization at 800 °C, the lignin-derived porous carbon displays a high specific capacitance (223.6 F·g–1 at 0.1 A·g–1) and excellent cycling ability with good capacitance retention. In this present study, the resultant lignin-derived porous carbon was used as the electrode of a supercapacitor, illustrating yet another potential high-value use for lignin, namely as a candidate for the sustainable fabrication of main supercapacitor components.

关键词： lignin     porous carbon     electrode     supercapacitor    

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标题 作者 时间 类型 操作

Performance of steel bridge deck pavement structure with ultra high performance concrete based on resin

期刊论文

Micromixing performance of the teethed high shear mixer under semi-batch operation

期刊论文

Experimental research on cyclone performance at high temperature

LI Wenqi, CHEN Jianyi

期刊论文

Recovery and reuse of floc sludge for high-performance capacitors

期刊论文

Effect of cavity defect on the triaxial mechanical properties of high-performance concrete

Yanbin ZHANG; Zhe WANG; Mingyu FENG

期刊论文

Flexural and longitudinal shear performance of precast lightweight steel–ultra-high performance concrete

期刊论文

Development and road performance of clear asphalt with high transparency and adhesion

期刊论文

Construction of interfacial dynamic bonds for high performance lignin/polymer biocomposites

期刊论文

Shear behavior of ultra-high-performance concrete beams prestressed with external carbon fiber-reinforced

期刊论文

Fast determination of tobramycin by reversed-phase ion-pair high performance liquid chromatography with

Liang ZHU, Jingkang WANG

期刊论文

Behavior and strength of headed stud shear connectors in ultra-high performance concrete of composite

Jianan QI, Yuqing HU, Jingquan WANG, Wenchao LI

期刊论文

Experimental investigations of internal energy dissipation during fracture of fiber-reinforced ultra-high-performance

Eric N. LANDIS, Roman KRAVCHUK, Dmitry LOSHKOV

期刊论文

Fabrication of high-performance pervaporation composite membrane for alkaline wastewater reclamation

期刊论文

Freshwater algae chemotaxonomy by high-performance liquid chromatographic (HPLC) analysis

Yansong HOU, Wei LIANG, Liping ZHANG, Shuiping CHENG, Feng HE, Zhenbin WU

期刊论文

Fabricating sustainable lignin-derived porous carbon as electrode for high-performance supercapacitors

期刊论文