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Qin Y.,Guangxi University | Long X.,Guangxi University | Ma X.,JiangSu Collaborative Innovation Center for Building Energy Saving and Construction Technology | Huang H.,Guangxi University
Cold Regions Science and Technology | Year: 2017

Building roadways through permafrost corridors is challenged by the presence of permafrost stratum, which is sensitive to the changes of the heat transfer balance at the ground surface. Due to the construction of the embankment, some reflected radiation from the nearby ground is trapped and absorbed by the side slope. This additional absorption of the embankment may be detrimental to the thermal stability of the permafrost stratum but has not been understood. Here we present two theoretical models to estimate the solar absorption of the embankment and we compare the prediction by the models against the experimental measurements. One is the solar trapping model and the other is the surface roughness model. The former is relatively complicate but it can estimate the macro-reflectivity/absorptivity of the embankment and of the side slope, respectively. The latter is relatively straightforward but can estimate the macro-reflectivity/absorptivity of the embankment only. It is found that the embankment absorbs more sunlight than the adjacent ground and that for a typical embankment, the macro-absorptivity of the embankment is 0.01–0.05 lower than its micro-absorptivity. This minimal difference suggests that the solar absorption of an embankment can be curtailed by raising the embankment's albedo, which can be done by flatting the side slope surface and painting the slope with high-reflectivity. © 2017 Elsevier B.V.


Li J.,China University of Mining and Technology | Li J.,Kaifeng University | Li J.,JiangSu Collaborative Innovation Center for Building Energy Saving and Construction Technology | Ji Y.-S.,China University of Mining and Technology | And 7 more authors.
KSCE Journal of Civil Engineering | Year: 2017

Objective: This study aims to improve the coagulation time, strength, and construction cost of magnesium phosphate cement. Methods: We analyzed the microstructure changes in the hardened magnesium phosphate cement paste through qualitative analysis, quantitative test, microscopic examination, and research regarding adding different concentrations of acetic acid on magnesium phosphate cement slurry time, effects of flow resistance, and mechanical properties. Results: When a moderate amount of AA was used, the setting time of MAPC mortar was significantly prolonged but was later reduced as the concentration increased. In the early phase, the degree of MAPC mortar hydration increased, whereas compressive strength significantly increased initially and increased slowly in the later phase. The crystal morphology and size of MAPC hydrates changed, and hardened MAPC became more compact in structure. The AA absorbed some ammonia in the MAPC condensation. Conclusion: Acetic acid can effectively regulate coagulation time, induce early hydration reaction rate, and improve the performance of magnesium phosphate cement, which can reduce the construction cost of magnesium phosphate cement. © 2017 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg


Zhou S.,China University of Mining and Technology | Zhou S.,Jiangsu Collaborative Innovation Center for Building Energy Saving and Construction Technology | Lu H.,China University of Mining and Technology | Lu H.,Jiangsu Collaborative Innovation Center for Building Energy Saving and Construction Technology | And 2 more authors.
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2016

The middle (seriously) deteriorated beams were strengthened with CFRP and the flexural behaviors were tested. The coupling effect of concrete deterioration and rebar corrosion on the strengthening efficiency was studied, and the influences of deterioration degree and CFRP amount on the strengthening effect were discussed. The results show that two typical failure modes were found when the beams under the ultimate flexural load, tensile failure of CFRP and shear fracture of the bonding layer. At the initial stage of loading, the plane section assumption was applicable, but it disabled at the later stage when it fragilely destroyed. The displacement ductility factor μ△ decreased slowly as the deterioration of RC beams increased. The tensile stress of CFRP was less than its limit value when the beam failed. Calculation models corresponding to the failure modes were established based on the test results and theoretical analysis. The influence of CFRP amount on strengthening effect was analyzed, and then the determining method of strengthening time was proposed. © 2016, Editorial Board of Journal of CUMT. All right reserved.


Han C.,China University of Mining and Technology | Han C.,JiangSu Collaborative Innovation Center for Building Energy Saving and Construction Technology | Wang D.,China University of Mining and Technology | Wang D.,JiangSu Collaborative Innovation Center for Building Energy Saving and Construction Technology | And 4 more authors.
Xi'an Jianzhu Keji Daxue Xuebao/Journal of Xi'an University of Architecture and Technology | Year: 2016

In market economy-oriented society, realization of architectural design innovation requires the joint efforts of construction investment units (customer) and architects. In architectural design innovation activities, the attitude of architects faced with the innovation risk is an important factor in achieving architectural design innovation, and the construction investment units generally prompt the architects to overcome innovation risk and ensure the effective realization of architectural design innovation through two means of external incentives and supervision. Using the mathematical model to explore the architectural design innovation risk and effectiveness issues of external incentives and supervision, can reveal the effective factors of realization the architectural design innovation, and provide the guidance and advice for further research and promoting architectural design innovation. © 2016, Editorial Office of Journal of Xi'an University of Architecture & Technology. All right reserved.


Wu Y.,China University of Mining and Technology | Wu Y.,Jiangsu Collaborative Innovation Center for Building Energy Saving and Construction Technology | Lu H.,China University of Mining and Technology | Lu H.,Jiangsu Collaborative Innovation Center for Building Energy Saving and Construction Technology | And 3 more authors.
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2015

The failure modes, expansive crack width, flexural carrying capacity and load-deflection curves were studied based on the artificial environment. The coupling effects of rebar corrosion and concrete deterioration were focused on. The results show that expansive crack is not detected when the corrosion of rebar is below 3.27 percent, and the main failure mode is crushing of compressive concrete. The carrying strength decreases rapidly with the corrosion increasing. After the cracks appearing, the failure mode changes to the yield of rebar, but the carrying strength decreases slowly. As the deterioration of beams increasing, the peak value and slope of load-deflection reduce. The concrete cracks because of the corroded rebar, and the binding force of concrete to the rebar decreases. The coupling effects promote the degradation of the bond between them. And then the flexural behavior of beams decreases. The experimental phenomena was analyzed with theory, and the results of test and calculation were compared. ©, 2015, China University of Mining and Technology. All right reserved.


Li X.,China University of Mining and Technology | Li X.,Jiangsu Collaborative Innovation Center for Building Energy Saving and Construction Technology | Zhao Z.-H.,China University of Mining and Technology | Liang Y.-S.,China University of Mining and Technology | And 2 more authors.
Magazine of Concrete Research | Year: 2016

An experimental study was undertaken to investigate the cyclic behaviour of earthquake- and corrosion-damaged rectangular reinforced concrete (RC) columns. Nine un-corroded columns and nine columns corroded using an external current method were tested to evaluate the effects of reinforcement corrosion level, initial earthquake damage degree (EDD), retrofit method and loading pattern on their cyclic behaviour. The test results indicate that reinforcement corrosion deteriorated the cyclic behaviour of RC columns in terms of strength, ductility, low-cycle fatigue life, secant stiffness and cumulative energy dissipation capacity, while retrofitting with carbon fibre reinforced polymer wraps and high-strength grout greatly improved the cyclic behaviour of both the un-corroded and corroded columns. For columns with an initial EDD of less than about 30%, regardless of whether they were first corroded or not, their strength, fatigue life and cumulative energy dissipation capacity after retrofit were fully restored to the levels prior to earthquake damage, whereas the level of improvement in the initial secant stiffness of damaged columns after retrofit was affected by the reinforcement corrosion level and the initial EDD. The influence of loading pattern on the cumulative energy dissipation capacity of un-corroded and corroded columns was also studied.


Wu Y.-Z.,China University of Mining and Technology | Wu Y.-Z.,JiangSu Collaborative Innovation Center for Building Energy Saving and Construction Technology | Lv H.-L.,China University of Mining and Technology | Lv H.-L.,JiangSu Collaborative Innovation Center for Building Energy Saving and Construction Technology | And 2 more authors.
Construction and Building Materials | Year: 2016

An experimental investigation was conducted to explore the degradation model of bond stress between concrete and deformed steel bars with four different diameters (12, 16, 20 and 25 mm) to determine the coupling effects on the bond between deteriorated concrete and corroded steel bars. The results indicated that the failure mode of the specimens was primarily splitting failure; however, the marks of the steel bars at the interface between the deteriorated concrete and corroded steel bars became unclear as the corrosion ratio increased. The ultimate bond strength of the two specimens with the smaller diameters increased with deterioration before a crack appeared and then it decreased, whereas that of the two specimens with the larger diameters continuously decreased due to smaller protective concrete thickness. A simplified calculation model of the bond strength between the cracked concrete and heavily corroded deformed steel bars was established based on the bonding theory of concrete and plane steel bars suing the following factors: the corrosion ratio of the steel bars, the compressive strength of concrete, the width of the cracks in the concrete and the friction factor between the deteriorated concrete and corroded steel bars. © 2016


Wang Y.,China University of Mining and Technology | Wang Y.,Jiangsu Collaborative Innovation Center for Building Energy Saving and Construction Technology | Yuan G.,China University of Mining and Technology | Huang Z.,Brunel University | And 3 more authors.
Engineering Structures | Year: 2016

In this paper four large scale fire tests on the reinforced concrete slabs, under combined uni-axial in-plane and out-of-plane loading conditions with vertical restraint at four corners of the slabs, are presented. The research focuses on the quantitative relationship between horizontal restrained force and deformations, cracking patterns and spalling of the slabs in fire. Also the vertical restraint forces at the four corners of the slabs were measured in the tests. Comparisons of the results indicate that the compressive uni-axial in-plane loads have a considerable effect on the number and directions of cracks on the top of the concrete slabs in fire. The uni-axial in-plane restrained slabs have larger mid-span deflections and lower deflection recovery ratios than the slabs without in-plane loading. In addition, the test results indicate that increasing reinforcement ratio can effectively prevent the integrity failure of the restrained slabs. The research generates valuable test data which can be used to validate the numerical models developed by fellow researchers in the field of structural fire engineering. © 2016 Elsevier Ltd


Ding B.-D.,State Key Laboratory for Geomechanics & Deep Underground Engineering | Ding B.-D.,China University of Mining and Technology | Ding B.-D.,Jiangsu Collaborative Innovation Center for Building Energy Saving and Construction Technology | Lu H.-L.,State Key Laboratory for Geomechanics & Deep Underground Engineering | And 7 more authors.
Zhendong Gongcheng Xuebao/Journal of Vibration Engineering | Year: 2015

Through the experiment for a single-layer cylindrical reticulated shell under impact forces, this paper is intended to study the dynamic response and the dynamic stability of a single-layer cylindrical reticulated shell. The time history plots of the impact force, axial stress, node displacements and accelerations have been obtained using the dynamic strain gauge, force sensor, displacement sensor and acceleration sensors. According to the corresponding relationship between the different impact force amplitudes and the measured point displacements, the failure modes and forms of the reticulated shell model in terms of the dynamic stability are analyzed and the stability bearing capacity is determined. The results show that the impact force on the model takes the shape of triangular impulse and the acting periods of the impact vary from 15 to 30 ms, whose amplitude and width increase with the impact force and both are closely related with the model stiffness. There are global and local sensitivity rods for cylindrical reticulated shell under impact loads, which show strong shock resistance ability at post buckling while no continuous fracture under the vertex vertical impact. The detailed test model is established based on ANSYS/LS-DYNA in which the failure mode of the single-layer cylindrical reticulated shell has been simulated. After comparing the simulation results with the experimental results, the validity of the numerical simulation method is verified. © 2015, Nanjing University of Aeronautics an Astronautics. All right reserved.

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