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Literature review of reactive powder concrete

Jianzhu Jiegou Xuebao/Journal of Building structures 2015年第10期36卷 44-58页

作者： Zheng, Wenzhong Lv, Xueyuan Key Laboratory of Structures Dynamic Behavior and Control of China Ministry of Education Harbin Institute of Technology Harbin150090 China

This paper introduces the proportioning principles and technology of reactive powder concrete (RPC), and then summarizes RPC durability and high temperature resistance. It is found that in the calculation of bond-anchorage length, the appearance coefficient of steel bar is higher in RPC than in ordinary concrete. The flexural cracking strain of RPC beam is 705×10-6-864×10-6, higher than that of ordinary concrete beam, which is 80×10-6-120×10-6. The normal section limit compressive strain of RPC beam is 4 100×10-6-5500×10-6, higher than that of ordinary concrete beam, which is 3300×10-6. The plastic influence coefficient for sectional resisting moment of RPC beam increases with the longitudinal reinforcement ratio;the test value of inclined section shearing load-bearing capacity is lower than the calculated value due to lack of coarse aggregate interlock effect on both sides of inclined cracks in RPC beam. Compared with ordinary concrete, RPC possesses excellent performance of chloride ion permeability resistance, carbonation resistance, frost thawing resistance and sulfate resistance;RPC mixed with fiber appropriately can prevent thermal spalling effectively. Finally, this paper briefly introduces the pilot projects of RPC and manifested its broad application prospects. ©, 2015, Science Press. All right reserved.

关键词： Durability

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Experimental study on the lateral impact of fully clamped circular steel tubes

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Tianjin Daxue Xuebao (Ziran Kexue yu Gongcheng Jishu Ban)/Journal of Tianjin University Science and Technology 2016年 49卷 28-33页

作者： Zhang, Rong Zhi, Xudong Fan, Feng Wu, Qijian Key Laboratory of Structures Dynamic Behavior and Control of Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China

The performance of longitudinal welded steel tubes under drop hammer impact was experimentally *** order to simulate fixed conditions of specimen,loading mechanism platform and clamping device were *** influencing factors included:drop height of hammer,ratio of length to diameter of steel tube,and shape of *** results show that the failure mode of fully clamped tubes is shear failure,and with the increase of the impact energy,the deformation of circular steel tube goes through three stages:elastic small deformation stage,plastic large deformation stage,and shear failure stage. Drop height of hammer and ratio of length to diameter of steel tube have significant effects on strain growth rate,duration of impact and peak impact force. The shape of the plastic hinge is determined by the shape of the impact indenter. © 2016, Editorial Board of Journal of Tianjin University(Science and Technology). All right reserved.

关键词： Hammers

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Temperature and electric-field induced phase transitions, and full tensor properties of C-poled domain-engineered tetragonal 0.63Pb(Mg1/3Nb2/3)−0.37PbTiO3 single crystals

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Physical Review B 2016年第9期93卷 094104-094104页

作者： Limei Zheng Yujia Jing Xiaoyan Lu Ruixue Wang Gang Liu Weiming Lü Rui Zhang Wenwu Cao Condensed Matter Science and Technology Institute Harbin Institute of Technology Harbin 150080 China Key Laboratory of Structures Dynamic Behavior and Control of the Ministry of Education School of Civil Engineering Harbin Institute of Technology Harbin 150001 China Center for High Pressure Science and Technology Advanced Research Shanghai 201203 China Department of Mathematics Materials Research Institute The Pennsylvania State University University Park Pennsylvania 16802 USA

The phase-transition sequence of 0.67Pb(Mg1/3Nb2/3)−0.37PbTiO3 (PMN-0.37PT) single crystals driven by the electric (E) field and temperature is comprehensively studied. Based on the strain-E field loop, polarization-E field loop, and the evolution of domain configurations, the E field along the [011]C induced phase transitions have been confirmed to be as follows: tetragonal (T) → monoclinic (MC)→ single domain orthorhombic (O) phase. As the E field decreases, the induced O phase cannot be maintained and transformed to the MC phase, then to the coexistence state of MC and T phases. In addition, the complete sets of dielectric, piezoelectric, and elastic constants for the [011]C-poled domain-engineered PMN-0.37PT single crystal were measured at room temperature, which show high longitudinal dielectric, piezoelectric, and electromechanical properties (ɛ33T=10661,d33=1052pC/N, and k33=0.766). Our results revealed that the MC phase plays an important role in the high electromechanical properties of this domain-engineered single crystal. The temperature dependence of the domain configuration revealed that the volume fraction of the MC phase decreases with temperature accompanied by the reduction of ɛ33T,d31, and k31 due to the substantially smaller intrinsic properties of the T phase.

关键词： Electric polarization Ferroelectricity Phase transitions Piezoelectricity Ferroelectrics Piezoelectrics Relaxor ferroelectrics Polarization

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Ultrasonic guided waves sensing using optical fiber sensor 7

Ultrasonic guided waves sensing using optical fiber sensor

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7th International Conference on Structural Health Monitoring of Intelligent Infrastructure, SHMII 2015

作者： Zhou, W. Li, H. Dong, Y. Wang, A. Key Lab. of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China National Key Laboratory of Science and Technology on Tunable Laser Harbin Institute of Technology Harbin150001 China

Optical fiber sensors have been proven that they have potential as ultrasonic guided waves sensor for structural health monitoring and damage detection. They can be used to receive acoustic emission signals from dynamic structural damages or guided waves propagating in waveguide and excited by ultrasonic actuators. Optical fiber sensors based on Mach-Zehnder interferometer were investigated in this work. Their sensing properties were explored experimentally using Lamb waves excited by a piezoelectric wafer in an aluminum plate. Spiral shape with different size was selected to increase their sensitivity. Experiments were also conducted to examine the voltage responses received by this type of sensor, and investigate results of tuning frequency. © 2015, International Society for Structural Health Monitoring of Intelligent Infrastructure, ISHMII. All rights reserved.

关键词： Structural health monitoring

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Seismic Behavior of Steel Plate Shear Walls-Steel Frame

Seismic Behavior of Steel Plate Shear Walls-Steel Frame

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The 2nd International Conference on Materials Science and Engineering Technology (MSET 2015)

作者： SHAO Fengru SHAO Yongsong Transportation Dept China Academy of Civil Aviation Science and Technology Key Lab of Structures Dynamic Behaviour and Control (Harbin Institute of Technology) Ministry of Education School of Civil Engineering Harbin Institute of Technology

A model with the ratio of 1:4 of a six layers' semi-rigid steel frame-steel plate shear wallssystem has been tested on the shaking *** strain variation of the steel plate shear wallsand the system's seismic behaviors to different kinds of seismic waves from four different siteclassification and with different peakaccelerationwere analyzed to provide theoretical and experimental evidence to the real projects.

关键词： semi-rigidjoints frame-shearwalls shaking table testing seismic behavior

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Experimental validation of a signal-based approach for structural earthquake damage detection using fractal dimension of time frequency feature

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Earthquake Engineering and Engineering Vibration 2014年第4期13卷 671-680页

作者： Tao Dongwang Mao Chenxi Zhang Dongyu Li Hui Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering Mechanics China Earthquake Administration Key Lab of Structures Dynamic Behavior and Control (Harbin Institute of Technology) Ministry of Education Center of Structural Monitoring and Control School of Civil Engineeing Harbin Institute of Technology

This article extends a signal-based approach formerly proposed by the authors, which utilizes the fractal dimension of time frequency feature （FDTFF） of displacements, for earthquake damage detection of moment resist frame （MRF）, and validates the approach with shaking table tests. The time frequency feature （TFF） of the relative displacement at measured story is defined as the real part of the coefficients of the analytical wavelet transform. The fractal dimension （FD） is to quantify the TFF within the fundamental frequency band using box counting method. It is verified that the FDTFFs at all stories of the linear MRF are identical with the help of static condensation method and modal superposition principle, while the FDTFFs at the stories with localized nonlinearities due to damage will be different from those at the stories without nonlinearities using the reverse-path methodology. By comparing the FDTFFs of displacements at measured stories in a structure, the damage-induced nonlinearity of the structure under strong ground motion can be detected and localized. Finally shaking table experiments on a 1：8 scale sixteen-story three-bay steel MRF with added frictional dampers, which generate local nonlinearities, are conducted to validate the approach.

关键词： earthquake damage detection time frequency feature fractal dimension signal-based shaking table test frictional damper

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Methods for determination of residual mortar content adhered to recycled aggregate

Methods for determination of residual mortar content adhered...

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4th International Conference on Civil Engineering, Architecture and Building Materials, CEABM 2014

作者： Jia, Chen Yan, Jia Chuan Hu, Qiong Zou, Chao Ying Chen, Fa Xin Key Lab of Structures Dynamic Behaviour and Control Harbin Institute of Technology Ministry of Education Heilongjiang Harbin 150090 China School of Civil Engineering Harbin Institute of Technology Heilongjiang Harbin 150090 China

ISBN: (纸本)9783038351641

To study the methods for determination of residual mortar content adhered to recycled aggregate, this paper aims at three methods which are apparent density method, quench hot method and sulfate solution freezing-thawing method. These methods were compared by experiments and their basic principles were also respectively stated. The principles of the latter two methods are similar, which are to separate the residual mortar and aggregate by external factors. But the effects of the sulfate solution freezing-thawing method is better than that of quench hot method. Finally, the best method is chosen to provide some theoretical evidence and research methods in studies and uses of recycled concrete. © (2014) Trans Tech Publications, Switzerland.

关键词： Mortar

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Research on deterioration of anchoring performance between anchorages to steel bars for prestressed concrete under fire

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Jianzhu Jiegou Xuebao/Journal of Building structures 2014年第3期35卷 110-118页

作者： Hou, Xiaomeng Zheng, Wenzhong Sun, Hongyu Key Laboratory of Structures Dynamic Behavior and Control of China Ministry of Education Harbin Institute of Technology Harbin 150090 China

In order to research the deterioration of anchoring performance between anchorages to steel bars for prestressed concrete under fire, 65 prestressed anchorage systems were tested under elevated temperatures. The typical tested prestressed anchorage system was specifically designed, which composed by JXM-clip anchorage, 7 steel bar for prestressed concrete (with a characteristic strength fptk=970 MPa) with surrounding concrete and a loading frame. A total of 29 unsealed prestressed anchorage systems and 18 prestressed anchorage systems with insulation were conducted as transient-state tests, while 18 prestressed anchorage systems were conducted as steady-state tests. The test variables included stress level (0.2~0.7), temperature (20~800°C), insulation (sealing anchorages by grouting, fire resistive coating and sealing anchorages by grouting and coating) and heating rate (10.0, 26.7°C/min). Transient-state test results from unsealed prestressed anchorage systems show that the failure mode of prestressed anchorage system is through slippage of anchorages. Lower the stress level, temperature and heating rate are, the higher will be the failure time in prestressed anchorage systems. In steady-state tests, failure mode of prestressed anchorage system is rupture of steel bar for prestressed concrete in temperature range of 20~400°C, while failure mode is through slippage of anchorages in temperature range of 400~800°C. Anchorages after elevated temperatures can not be applied in new structures. Test results from prestressed anchorage systems with insulation show that failure mode of anchorage systems is through slippage of anchorages, and insulations do not change the failure mode at elevated temperatures. As compared with unsealed prestressed anchorage systems, the failure time of prestressed anchorage systems with insulations is increased above 100%. It is not safe to apply the recommendation of fire resistive coating thickness for steel structures in GB 14907-2002 'Fir

关键词： Failure modes

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Establishment of frost resistance model for autoclaved fly ash bricks

Establishment of frost resistance model for autoclaved fly a...

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The 2014 IMSS International Conference on Future Manufacturing Engineering(ICFME 2014)

作者： Shuang Lu Zheng Wang Key Laboratory of Structures Dynamic Behavior and Control Ministry of EducationHarbin Institute of Technology

In cold area,the freeze-thaw cycling durability of building materials is one of the primary influence *** paper studied on the loss ratio of the relative dynamic elastic modulus of the autoclaved fly ash bricks,which is according to the ultrasonic speed after suffering different freeze-thaw *** that,the corresponding numerical model has been established *** results indicate that the calculated results by the model can fit with the experimental data very ***,the model can be applied to predict the service life by using environment parameters as the factors in the model.

关键词： fly ash brick freeze-thaw cycling model dynamic elastic modulus durability

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Hysteretic phase transition sequence in 0.67Pb(Mg1/3Nb2/3)O3−0.33PbTiO3 single crystal driven by electric field and temperature

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Physical Review B 2015年第18期91卷 184105-184105页

作者： Limei Zheng Xiaoyan Lu Hengshan Shang Zengzhe Xi Ruixue Wang Junjun Wang Peng Zheng Wenwu Cao Condensed Matter Science and Technology Institute Harbin Institute of Technology Harbin 150080 China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education School of Civil Engineering Harbin Institute of Technology Harbin 150001 China Shaanxi Key Laboratory of Photoelectric Functional Materials and Devices School of Materials and Chemical Engineering Xi'an Technological University Xi'an 710032 China College of Electronics and Information Hangzhou Dianzi University Hangzhou 310018 China Department of Mathematics and Materials Research Institute Pennsylvania State University University Park Pennsylvania 16802 USA

Domain pattern variations with temperature were studied by polarizing light microscopy for the morphotropic phase boundary composition 0.67Pb(Mg1/3Nb2/3)O3−0.33PbTiO3 (PMN-0.33PT) single crystal. At room temperature, the monoclinic MA phase is the dominant phase in the unpoled crystal, which coexists with a small fraction of the tetragonal (T) phase. The orientation of spontaneous polarization was calculated to be ∼4.8∘ away from the pseudocubic 〈111〉C in the {001}C plane family. Under an electric field of 6 kV/cm along [011]C, a single domain orthorhombic (O) phase was induced but partially switched back to MA a few hours after the removal of the E field. It was found that the temperature induced phase transition sequence of the [011]C poled PMN-0.33PT single crystal is strongly hysteretic. On heating, the phase transition sequence is as follows: coexistence of O phase and MA→rhombohedral→monoclinicMC→cubic(C). On cooling, the phase transition sequence is given by C→T→MA. The complete set of dielectric, piezoelectric, and elastic constants for the [011]C poled PMN-0.33PT single crystal was measured, which showed the strong feature of the single domain O phase with high shear (d15=2321pC/N,d24=1941pC/N) and low longitudinal piezoelectric coefficients (d33=165pC/N).

关键词： SINGLE crystals ELECTRIC fields TEMPERATURE POLARIZATION (Electricity) PIEZOELECTRIC devices

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