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Numerical study on flexural behaviors of steel reinforced engineered cementitious composite(ECC) and ECC/concrete composite beams

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Science China(Technological Sciences) 2014年第3期57卷 637-645页

作者： YUAN Fang PAN JinLong WU YuFei Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education Southeast University Department of Civil and Architectural Engineering City University of Hong Kong

Engineered cementitious composite(ECC)is a class of high performance cementitious composites with pseudo strain-hardening behavior and excellent crack control *** of concrete with ECC can largely reduce the cracking and durability problems associated with brittleness of *** this paper,a simplified constitutive model of the ECC material was applied to simulate the flexural behaviors of the steel reinforced ECC and ECC/concrete composite beams with finite element *** simulation results are found to be in good agreement with test results,indicating that the finite element model is reasonably accurate in simulating the flexural behaviors of the steel reinforced ECC flexural *** effects of the ECC modulus,ECC tensile ductility,ECC thickness and ECC position on flexural behaviors in terms of ultimate moment,deflection and the maximum crack width of the steel reinforced ECC or ECC/concrete composite beam are hence evaluated.

关键词： engineered cementitious composite(ECC) constitutive model flexural behavior finite element

flexural behaviors of FRP strengthened corroded RC beams

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Journal of Southeast University(English Edition) 2014年第1期30卷 77-83页

作者：潘金龙王路平袁方黄毅芳东南大学混凝土及预应力混凝土教育部重点实验室南京210096 中国联合工程公司杭州310022

The flexural behavior of eight FRP （ fiber reinforced polymer） strengthened RC （reinforced concrete） beams with different steel corrosion rates are numerically studied by Ansys finite element software. The influences of the corrosion rate on crack pattern, failure mechanism, ultimate strength, ductility and deformation capacity are also analyzed. Modeling results show that the beams with low corrosion rates fail by the crushing of the concrete in the compression zone. For the beams with medium corrosion rates, the bond slip between the concrete and the longitudinal reinforcement occurs after steel yielding, and the beams finally fail by the debonding of the FRP plates. For the beams with high corrosion rates, the bond slip occurs before steel yielding, and the beams finally fail by the crushing of the concrete in the compression zone. The higher the corrosion rates of the longitudinal reinforcement, the more the carrying capacity of FRP strengthened RC beams reduces. The carrying capacity of RCB-1 （the corrosion rate is 0） is 115 kN, and the carrying capacity of RCB-7 （the corrosion rate is 20% ） is 42 kN. The deformation capacity of FRP strengthened corroded RC beams is higher than that of FRP strengthened uucorroded RC beams. The ultimate deflection of RCB-1 and RCB-7 are 20 mm and 35 nun, respectively, and the ultimate deflection of RCB-5 （the corrosion rate is 10% ） reaches 60 ilUn.

关键词： corroded reinforced concrete beam FRP ( fberreinforced polymer ) strengthening numerical analysis flexural behavior

Experimental and numerical study on flexural behaviors of steel reinforced engineered cementitious composite beams

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Journal of Southeast University(English Edition) 2014年第3期30卷 330-335页

作者：蔡景明潘金龙袁方东南大学混凝土及预应力混凝土教育部重点实验室南京210096

To investigate the flexural behaviors of steel reinforced engineered cementitious composite （ECC） beams, the behaviors of the steel reinforced ECC beam and the conventional steel reinforced concrete beam subjected to flexural load are experimentally compared. The experimental results show that the flexural strength and ductility of the steel reinforced ECC beam are 24.8% and 187.67% times larger than those of the steel reinforced concrete beam, and the substitution of concrete with ECC can significantly delay the propagation of cracks. Additionally, a simplified constitutive model of the ECC material is used to simulate the flexural behaviors of beams by the finite element analysis （FEA）. The results show a good agreement between the simulation and test results. The crack width of the steel reinforced ECC beam can be limited to 0.4 mm under the service load conditions. The application of ductile ECC can significantly increase the flexural performance in terms of flexural strength, deformation capacity and ductility of the beams.

关键词： engineered cementitious composites (ECC) ductility flexural behavior finite element

Exploring the mechanical properties of steel-and polypropylene-reinforced ultra-high-performance concrete through numerical analyses and experimental multi-target digital image correlation

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Frontiers of Structural and Civil Engineering 2023年第8期17卷 1228-1248页

作者： Behrooz DADMAND Hamed SADAGHIAN Sahand KHALILZADEHTABRIZI Masoud POURBABA Amir MIRMIRAN Department of Civil Engineering University of RaziKermanshah ***Iran Department of Civil Engineering University of TabrizTabriz ***Iran Ingram School of Engineering Texas State UniversitySan MarcosTX 78666USA University of Texas at Tyler TylerTX 75799USA

This study presents experimental and numerical investigations on the mechanical properties of ultrahigh-performance concrete(UHPC)reinforced with single and hybrid micro-and macro-steel and polypropylene *** this purpose,a series of cubic,cylindrical,dog-bone,and prismatic beam specimens(total fiber by volume=1%,and 2%)were tested under compressive,tensile,and flexural loadings.A method,namely multi-target digital image correlation(MT-DIC)was used to monitor the displacement and deflection *** obtained experimental data were subsequently used to discuss influential parameters,i.e.,flexural strength,tensile strength,size effect,*** analyses were also carried out using finite element software to account for the sensitivity of different ***,nonlinear regression analyses were conducted to obtain the flexural load-deflection *** results showed that the MT-DIC method was capable of estimating the tensile and flexural responses as well as the location of the crack with high *** addition,the regression analyses showed excellent consistency with the experimental results,with correlation coefficients close to ***,size-effect modeling revealed that modified Bazant theory yielded the best estimation of the size-effect phenomenon compared to other models.

关键词： UHPC MT-DIC flexural behavior tensile behavior steel fiber polypropylene fiber

同方期刊数据库

Properties and calculation of normal section bearing capacity of RC flexural beam with skin textile reinforcement

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Journal of Central South University 2013年第6期20卷 1731-1741页

作者：尹世平吕恒林徐世烺 State Key Laboratory for Geomechanics & Deep Underground Engineering(China University of Mining and Technology) Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering School of Mechanics & Civil EngineeringChina University of Mining and Technology College of Civil Engineering and Architecture Zhejiang University

In order to overcome the wide crack of ordinary reinforced concrete (RC) at service stage which affects the service performance and durability of structures,a kind of concrete structure with skin textile reinforcement is proposed,namely a part of concrete cover of RC members is replaced by textile reinforced concrete (TRC).The flexural experimental results indicate that when the reinforcement ratios of steel bars are constant,compared with control beams,the average value of crack loads of the beams,whose reinforcement ratios of textile are 0.018%,0.036% and 0.055%,increases by 15.5%,20.4% and 31.1%,respectively,the average value of yield loads respectively increases by 12.5%,19.9% and 21.1% and the average value of ultimate loads respectively increases by 8.5%,26.0% and 44.0%,*** reduction in cracks width and spacing is observed for specimens with a TRC layer,and when the beams yield,the maximum crack width of the beam with textile stuck no sand and the beam with textile stuck sand is reduced by around 60% and 70%,*** treatment of textile and mixing polypropylene fiber into fine grained concrete contribute to enhance the service performance of the flexural *** U-shaped hoop has almost no effect on the control of the crack ***,the calculation method of ultimate bearing capacity of this flexural component with TRC layer was *** between the calculated and the experimental values reveals satisfactory agreement,and the maximum error is no more than 6%.

关键词： reinforced concrete textile crack width limitation flexural behavior calculation of flexural capacity

behavior of preloaded RC beams strengthened with CFRP laminates

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第3期7卷 436-444页

作者：张爱晖金伟良李贵炳 Department of Civil Engineering Zhejiang University Hangzhou 310027 China

Eighteen reinforced concrete beams, including 16 beams strengthened with CFRP laminate at different levels of preload and 2 control beams, were tested to investigate the influence of preload level on flexural behavior of CFRP-strengthened RC beam. The experimental parameters include rebar ratios, number of plies of CFRP laminates and preload level at the time of strengthening. Theoretical analysis was also carried out to explain the experimental phenomena and results. The experimental and theoretical results indicated that the preload level has more influence on the stiffness and deflection of the strengthened beam, both at post-cracking and post-yielding stage, than that on the yielding and ultimate flexural strength of the strengthened beam. The main failure mode of CFRP-strengthened beam is the intermediate crack-induced debonding of CFRP laminates, provided that the development length of CFRP laminates and shear capacity of the beam are sufficient.

关键词： Beam Strengthen CFRP flexural behavior Preload level

Preparation and Reinforcement Adaptability of Jute Fiber Reinforced Magnesium Phosphate Cement Based Composite Materials

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 999-1009页

作者：刘芯州郭远臣 WANG Rui XIANG Kai WANG Xue YE Qing College of Civil Engineering Chongqing Three Gorges UniversityChongqing 404100China

To improve the brittleness characteristics of magnesium phosphate cement-based materials(MPC)and to promote its promotion and application in the field of structural reinforcement and repair,this study aimed to increase the toughness of MPC by adding jute fiber,explore the effects of different amounts of jute fiber on the working and mechanical properties of MPC,and prepare jute fiber reinforced magnesium phosphate cement-based materials(JFRMPC)to reinforce damaged *** improvement effect of beam performance before and after reinforcement was compared,and the strengthening and toughening mechanisms of jute fiber on MPC were explored through microscopic *** experimental results show that,as the content of jute fiber(JF)increases,the fluidity and setting time of MPC decrease continuously;When the content of jute fiber is 0.8%,the compressive strength,flexural strength,and bonding strength of MPC at 28 days reach their maximum values,which are increased by 18.0%,20.5%,and 22.6%compared to those of M0,*** beam strengthened with JFRMPC can withstand greater deformation,with a deflection of 2.3 times that of the unreinforced beam at *** strain of the steel bar is greatly reduced,and the initial crack and failure loads of the reinforced beam are increased by 192.1%and 16.1%,respectively,compared to those of the unreinforced *** JF added to the MPC matrix dissipates energy through tensile fracture and debonding pull-out,slowing down stress concentration and inhibiting the free development of cracks in the matrix,enabling JFRMPC to exhibit higher strength and better *** JF does not cause the hydration of MPC to generate new compounds but reduces the amount of hydration products generated.

关键词： magnesium phosphate cement jute fiber reinforcement of damaged beam flexural behavior

Performance of Epoxy-Repaired Corroded Reinforced Concrete Beams

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Transactions of Nanjing University of Aeronautics and Astronautics 2015年第5期32卷 579-584页

作者：李洪明吴瑾王喆尚保康 College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics

Reinforcement corrosion has a serious impact on the durability and safety of reinforced concrete *** reinforced concrete(RC)beam specimens are *** beam specimens are subjected to accelerated corrosion with the constant current,beam specimens are repaired with epoxy mortar and the flexural test of beams is *** the behaviors of repaired corroded reinforced concrete beams are *** experimental results show that cracking and ultimate loads of corroded RC beams are enhanced after being *** the strain distributions measured across sections of beam specimens still obey the assumption of plane *** being repaired,the number of cracks decreases and the crack spacing increases.

关键词： corrosion reinforced concrete beam epoxy mortar flexural behavior repair

flexural response of reinforced concrete beams strengthened with post-poured ultra high toughness cementitious composites layer

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Journal of Central South University 2011年第3期18卷 932-939页

作者：王楠徐世烺 State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian Institute of Building Scientific Research & Design Stock Co. Ltd.

Four-point bending tests were conducted up to failure on eleven reinforced concrete (RC) beams and strengthening beams to study the effectiveness of externally pouring ultra high toughness cementitious composites (UHTCC) on improving the flexural behavior of existing RC *** strengthening materials included UHTCC and high strength grade *** parameters,such as thickness and length of strengthening layer and reinforcement in post-poured layer,were *** flexural behavior,failure mode and crack propagation of composite beams were *** test results show that the strengthening layer improves the cracking and ultimate load by increasing the cross section *** UHTCC material into strengthening not only improves the bearing capacity of the original specimens,but also disperses larger cracks in upper concrete into multiple tightly-spaced fine cracks,thus prolonging the appearance of harm surface cracks and increasing the durability of existing *** with post-poured concrete,UHTCC is more suitable for working together with *** load?deflection plots obtained from three-dimensional finite-element model (FEM) analyses are compared with those obtained from the experimental results,and show close correlation.

关键词： ultra high toughness cementitious composities strengthening beams flexural behavior post-poured layer