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Fatigue reliability quantitative analysis of cement concrete for highway pavement under high stress ratio 被引量:5
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作者 薛彦卿 黄晓明 +2 位作者 钱吮智 马涛 邹湘衡 《Journal of Southeast University(English Edition)》 EI CAS 2012年第1期94-99,共6页
In order to obtain the change law of the fatigue reliability of cement concrete for highway pavement under high stress ratios, first, the probability densities of monotonic random variables including concrete fatigue ... In order to obtain the change law of the fatigue reliability of cement concrete for highway pavement under high stress ratios, first, the probability densities of monotonic random variables including concrete fatigue life are deduced. And then, the fatigue damage probability densities of the Miner and Chaboche-Zhao models are deduced. By virtue of laboratory fatigue test results, the fatigue damage probability density functions of the two models can be obtained, considering different stress ratios. Finally, substituting load cycles into them, the change law of cement concrete fatigue reliability about load cycles can be acquired. The results show that under the same stress ratio, with the increase in the load cycle, the fatigue reliability declines from almost 100% to 0% gradually. No matter under what stress ratio, during the initial stage of the load action, there is always a relatively stable phase for fatigue reliability. With the increase in the stress ratio, the stable phase gradually shortens and the load cycle corresponding to the reliability of 0% also decreases. In the descent phase of reliability, the higher the stress ratio is, the lower the concrete reliability is for the same load cycle. Besides, compared with the Chaboche-Zhao fatigue damage model, the Miner fatigue damage model is safer. 展开更多
关键词 cement concrete fatigue life fatigue damage probability density function high stress ratio fatigue reliability
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Effects of binder strength and aggregate size on the compressive strength and void ratio of porous concrete 被引量:22
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作者 P. Chindaprasirt S. Hatanaka +2 位作者 N. Mishima Y. Yuasa T. Chareerat 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2009年第6期714-719,共6页
To test the influence of binder strength, porous concretes with 4 binder strengths between 30.0-135.0 MPa and 5 void ratios between 15%-35% were tested. The results indicated that for the same aggregate, the rates of ... To test the influence of binder strength, porous concretes with 4 binder strengths between 30.0-135.0 MPa and 5 void ratios between 15%-35% were tested. The results indicated that for the same aggregate, the rates of strength reduction due to the increases in void ratio were the same for binders with different strengths. To study the influence of aggregate size, 3 single size aggregates with nominal sizes of 5.0, 13.0 and 20.0 mm (Nos. 7, 6 and 5 according to JIS A 5001) were used to make porous concrete. The strengths of porous concrete are found to be dependent on aggregate size. The rate of strength reduction of porous concrete with small aggregate size is found to be higher than that with larger aggregate size. At the same void ratio, the strength of porous concrete with large aggregate is larger than that with small aggregate. The general equations for porous concrete are related to compressive strength and void ratio for different binder strengths and aggregate sizes. 展开更多
关键词 cement paste porous concrete compressive strength void ratio
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Effect of Hydration Aging and Water Binder Ratio on Microstructure and Mechanical Properties of Sprayed Concrete 被引量:4
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作者 牛荻涛 王家滨 WANG Yan 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第4期745-751,共7页
In order to study the durability of sprayed concrete (shotcrete), effects of different hydration aging and water-binder ratio (w/b) on the microstructure of cement paste and basic mechanical properties of test spe... In order to study the durability of sprayed concrete (shotcrete), effects of different hydration aging and water-binder ratio (w/b) on the microstructure of cement paste and basic mechanical properties of test specimens were investigated. The phase composition, mass percentage of ettringite and portland in hydration production and microstructure were characterized by X-ray diffraction (XRD), thermo gravimetry-differential scanning calorimetry (TG-DSC) and scanning electron microscopy (SEM), respectively. The experimental results showed that changes in phase composition was more significant than those of water-binder ratio. With hydration aging and water-binder ratio increased, the mass percentage of ettringite and portland was decreased from 4.42%, 1.49% to 3.31%, 1.35%, respectively and the microstructure of paste was significantly compacted. Likewise, the mechanical properties including cubic compressive strength and splitting tensile strength were rised obviously. 展开更多
关键词 hydration aging water binder ratio (w/b) sprayed concrete(shortcrete) microstructuremechanical properties
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Spherical cavity-expansion model for penetration of reinforced-concrete targets 被引量:3
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作者 Y.J.Deng W.J.Song X.W.Chen 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2019年第3期535-551,共17页
The feature of reinforcing bars is introduced into dynamic cavity-expansion theory. Based on the elastic-plastic response penetration model of plain (i.e., unreinforced) concrete (Forrestal and Tzou, 1997), a dynamic ... The feature of reinforcing bars is introduced into dynamic cavity-expansion theory. Based on the elastic-plastic response penetration model of plain (i.e., unreinforced) concrete (Forrestal and Tzou, 1997), a dynamic spherical cavity-expansion penetration model for reinforced-concrete targets is developed with consideration of the circumferential restriction effect derived from reinforcing bars in the crushed region. The theoretical solution and simplified calculation formula for the cavity radial stress in incompressible and compressible reinforced concrete are obtained by introducing a reinforcement ratio as the volume fraction of rebars in the concrete target. A damping function is presented to describe the restriction effect of a single layer of reinforcing bars on the surrounding concrete, thus establishing a model to calculate the penetration resistance of multilayer reinforced-concrete targets. Compared with test data for the penetration depth, this model considering the circumferential restriction effect produces better results compared with the existing theory. 展开更多
关键词 Dynamic cavity-expansion theory REINFORCED concrete PENETratioN resistance REINFORCEMENT ratio
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Behavior of High Water-cement Ratio Concrete under Biaxial Compression after Freeze-thaw Cycles 被引量:2
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作者 SHRUG Huaishuai SONG Yupu OU Jinpin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2008年第4期589-594,共6页
The high water-cement ratio concrete specimens under biaxial compression that completed in a triaxial testing machine were experimentally studied. Strength and deformations of plain concrete specimens in two loading d... The high water-cement ratio concrete specimens under biaxial compression that completed in a triaxial testing machine were experimentally studied. Strength and deformations of plain concrete specimens in two loading direction under biaxial compression with stress ratio of a=0, 0.25, 0.5, 0.75, 1.0 were obtained after 0, 25, 50 cycles of freeze-thaw. Influences of freeze-thaw cycles and stress ratio on the peak stress and deformation of this point were analyzed according to the experimental results, Based on the test data, the failure criterion expressed in terms of principal stress after different cycles of freeze-thaw, and the failure criterion with consideration of the influence of freeze-thaw cycle and stress ratio were proposed respectively. 展开更多
关键词 concrete freeze-thaw cycles stress ratio strength criteria
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Improved designed method of pervious concrete based on optimal volume ratio of paste to aggregate 被引量:7
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作者 BA Ming-fang QI Xin-yu +3 位作者 ZHENG Yu-hang HUANG Guo-yang HE Zhi-min LIU Jun-zhe 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第5期1534-1545,共12页
An improved design method of pervious concrete was proposed to lower the deviation between the designed and actual porosity and maintain both mechanical property and permeability of pervious concrete. The improved des... An improved design method of pervious concrete was proposed to lower the deviation between the designed and actual porosity and maintain both mechanical property and permeability of pervious concrete. The improved design method is mainly based on the optimal volume ratio of paste to aggregate(VRPA), which was determined by testing the average thickness of cement paste coating aggregate. The performances of pervious concrete designed by the traditional method and the improved one were compared. The results show that with the increase of designed porosity, the reduction of compressive strength and flexural strength of pervious concrete designed by the improved method is significantly smaller than those designed by the traditional one. The maximum deviation between the designed and actual porosity of the pervious concrete by the improved method is only 1.54%, which is far less than 8.7% obtained by the traditional one. Micro-structural analysis shows that the porous distribution of pervious concrete designed by improved method exhibits better uniformity. 展开更多
关键词 pervious concrete absolute volume method volume ratio of paste to aggregate mechanical properties porous structures PERMEABILITY
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Tests on Alkali-Activated Slag Foamed Concrete with Various Water-Binder Ratios and Substitution Levels of Fly Ash 被引量:6
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作者 Keun-Hyeok Yang Kyung-Ho Lee 《Journal of Building Construction and Planning Research》 2013年第1期8-14,共7页
To provide basic data for the reasonable mixing design of the alkali-activated (AA) foamed concrete as a thermal insulation material for a floor heating system, 9 concrete mixes with a targeted dry density less than 4... To provide basic data for the reasonable mixing design of the alkali-activated (AA) foamed concrete as a thermal insulation material for a floor heating system, 9 concrete mixes with a targeted dry density less than 400 kg/m3 were tested. Ground granulated blast-furnace slag (GGBS) as a source material was activated by the following two types of alkali activators: 10% Ca(OH)2 and 4% Mg(NO3)2, and 2.5% Ca(OH)2 and 6.5% Na2SiO3. The main test parameters were water-to-binder (W/B) ratio and the substitution level (RFA) of fly ash (FA) for GGBS. Test results revealed that the dry density of AA GGBS foamed concrete was independent of the W/B ratio an RFA, whereas the compressive strength increased with the decrease in W/B ratio and with the increase in RFA up to 15%, beyond which it decreased. With the increase in the W/B ratio, the amount of macro capillaries and artificial air pores increased, which resulted in the decrease of compressive strength. The magnitude of the environmental loads of the AA GGBS foamed concrete is independent of the W/B ratio and RFA. The largest reduction percentage was found in the photochemical oxidation potential, being more than 99%. The reduction percentage was 87% - 93% for the global warming potential, 81% - 84% for abiotic depletion, 79% - 84% for acidification potential, 77% - 85% for eutrophication potential, and 73% - 83% for human toxicity potential. Ultimately, this study proved that the developed AA GGBS foamed concrete has a considerable promise as a sustainable construction material for nonstructural element. 展开更多
关键词 ALKALI-ACTIVATED Foamed concrete Granulated Ground BLAST-FURNACE SLAG FLY ASH Water-to-Binder ratio Environmental Load
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Analysis of the Performances and Optimization of Polyurethane Concrete with a Large Percentage of Fly Ash
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作者 Tingting Huo Jiaquan Xue Zhi’an Fu 《Fluid Dynamics & Materials Processing》 EI 2023年第2期437-450,共14页
The properties of polyurethane concrete containing a large amount of fly ash are investigated,and accordingly,a model is introduced to account for the influence of fly ash fineness,water ratio,and loss of ignition(LOI... The properties of polyurethane concrete containing a large amount of fly ash are investigated,and accordingly,a model is introduced to account for the influence of fly ash fineness,water ratio,and loss of ignition(LOI)on its mechanical performances.This research shows that,after optimization,the concrete has a compressive strength of 20.8 MPa,a flexural strength of 3.4 MPa,and a compressive modulus of elasticity of 19.2 GPa.The main factor influencing 28 and 90 d compressive strength is fly ash content,water-binder ratio,and early strength agent content. 展开更多
关键词 Water-containing unsaturated polyurethane concrete fly ash ratio test strength test water content test mechanical properties
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Experimental research on shear carrying capacity of H-steel concrete composite beam with small shear span ratio 被引量:1
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作者 王钧 赵天石 +1 位作者 谢恒燕 郑文忠 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2010年第3期398-400,共3页
In order to investigate shear carrying capacity of H-steel concrete beam with small shear span ratio,shear test on 5 H-steel concrete composite beams with small span ratio (from 0.7 to 1.1) are reported,including test... In order to investigate shear carrying capacity of H-steel concrete beam with small shear span ratio,shear test on 5 H-steel concrete composite beams with small span ratio (from 0.7 to 1.1) are reported,including test design,test scheme,test method,failure characteristics and test results. Influences of shear span ratio,web of H steel and concrete on shear carrying capacity of this kind of beam are investigated. The main components comprising shear bearing capacity are analyzed. The results show that with the shear span ratio increasing,the contribution of web of H steel and concrete on shear carrying capacity decrease. Based on test data,the calculation formula of shear carrying capacity for this beam is established by curve fitting. 展开更多
关键词 concrete H-steel composite beam shear span ratio shear carrying capacity
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Experimental Study on Chloride Ion Penetration Resistance of Coal Gangue Concrete under Multi-Factor Comprehensive Action 被引量:1
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作者 Hongyu Chen Hongguang Zhu +1 位作者 Hongqiang Ma Mingyue Zhang 《World Journal of Engineering and Technology》 2019年第2期58-64,共7页
In order to investigate the chloride ion penetration resistance of coal gangue concrete under multi-factor comprehensive action, the non-steady-state accelerated chloride ion migration test was used to test the chlori... In order to investigate the chloride ion penetration resistance of coal gangue concrete under multi-factor comprehensive action, the non-steady-state accelerated chloride ion migration test was used to test the chloride diffusion law of coal gangue concrete specimens by crack width, curing temperature and water-cement ratio. Three groups of crack width (0 mm, 0.05 - 0.12 mm, 0.12 - 0.2 mm), three curing temperatures (high temperature 45, medium temperature 25, low temperature 10), three water cement ratios (0.3, 0.4, 0.5) were set in the experiment. The results show that when the curing temperature and water cement ratio are constant, the crack width less than 0.12 mm has little effect on the chloride content and chloride diffusion coefficient. When the crack width is larger than 0.12 mm, the chloride penetration depth increases with the crack width. The resistance to chloride ion penetration of gangue concrete is greatly influenced by the water cement ratio. The influ-ence degree of three factors on chloride ion migration coefficient of gangue concrete is as follows: water cement ratio > crack width > curing temperature. 展开更多
关键词 Coal GANGUE concrete CHLORIDE Ion PENETratioN Water CEMENT ratio Crack WIDTH CURING Temperature
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Comprehensive Analysis of the Effects of Superplasticizer Variation on the Workability and Strength of Ready-Mix Concrete
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作者 Tahsin Tareque Fahmid Tousif +2 位作者 Mirza Addaito Billah Abdullah Al Masum Jabir Seyedali Mirmotalebi 《Open Journal of Civil Engineering》 2023年第4期756-770,共15页
This experimental study aims to examine the influence of many crucial parameters on the workability and compressive strength of Ready-Mix Concrete (RMC). The study utilized two distinct varieties of superplasticizers ... This experimental study aims to examine the influence of many crucial parameters on the workability and compressive strength of Ready-Mix Concrete (RMC). The study utilized two distinct varieties of superplasticizers obtained from the local market. The fine aggregates utilized in this study were sourced from Sylhet sand, whereas the coarse aggregates were comprised of boulder crushed stone chips. The experimental procedures adhered to the requirements outlined by ASTM. A comprehensive investigation was conducted on a range of concrete compositions that used diverse chemical admixtures. The slump test was performed at regular intervals of 15 minutes until the slump value reached or fell below 3 cm after the mixing of the concrete. In the scenario involving two-stage admixture dosage, the second stage of admixture was introduced once the slump reached or dropped below 3 cm, following which the casting process was initiated. The process of curing concrete specimens consists of two distinct stages: the main stage and the final stage. Cylindrical specimens, with a diameter of 4 inches and a height of 8 inches, were manufactured for the purpose of evaluating their compressive strength at both 7 and 28 days. During the experimental trials, the water-cement (w/c) ratio was kept consistent, while different dosages of admixture were applied. The findings of the study indicate that the utilization of a two-stage dose of admixture resulted in enhanced and extended workability, along with higher strength of the concrete in comparison to specimens that did not incorporate any admixture. This research study enhances the comprehension of optimizing qualities of ready-mix concrete (RMC) by varying the superplasticizer, providing useful insights for the building sector. 展开更多
关键词 Admixture Dosage Slump Test Water-Cement ratio concrete Compositions Compressive Strength
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Research on Preparation and Influencing Fctors of High Calcium High Sulfate Ash to Autoclaved Aerated Concrete
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作者 WAN Jun JIA Shaohui 《矿物学报》 CAS CSCD 北大核心 2013年第S1期96-96,共1页
In this paper, a high calcium high sulfate ash as the main material, adding fly ash, lime, cement, gypsum and some modifiers to prepare autoclaved aerated concrete. The products complies with the technical requirement... In this paper, a high calcium high sulfate ash as the main material, adding fly ash, lime, cement, gypsum and some modifiers to prepare autoclaved aerated concrete. The products complies with the technical requirements of GB/T11968-2006. This paper also studies the influence of the physical methods and water ratio on autoclaved aerated concrete by high calcium high sulfate ash aerated concrete. The best ratio of water and Grinding time were found in practice study. 展开更多
关键词 HIGH CALCIUM HIGH SULFATE ASH autoclaved aerated concrete ratio of water LIME DENSIFICATION
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Influence of Axial Load Ratio on Shear Behavior of Through-Diaphragm Connections of Concrete-Filled Square Steel Tubular Columns 被引量:2
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作者 张广泰 韩建红 +1 位作者 荣彬 Apostolos Fafitis 《Transactions of Tianjin University》 EI CAS 2015年第4期341-346,共6页
Nonlinear finite element analysis and parametric studies were carried out to study the influence of axial load ratio on the shear behavior of the through-diaphragm connections of concrete-filled square steel tubular c... Nonlinear finite element analysis and parametric studies were carried out to study the influence of axial load ratio on the shear behavior of the through-diaphragm connections of concrete-filled square steel tubular columns. The analysis reveals that smaller axial load ratio can improve the shear bearing capacity and ductility while larger axial load ratio will decrease the shear behavior of the through-diaphragm connections. The parametric studies indicate that the axial load ratio should be limited to less than 0.4 and its influence should be considered in the analysis and design of such connections. 展开更多
关键词 through-diaphragm connection concrete-filled square steel TUBULAR COLUMN AXIAL load ratio shearbearing capacity DUCTILITY
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Equal Volumes of Sand and Gravel Concrete Mix Ratios in Cameroon and Its Effect on Concrete Compressive Strength
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作者 Patrick Bame Che Yamb Bell Emmanuel Ndigui Billong 《World Journal of Engineering and Technology》 2022年第3期539-549,共11页
In recent years, the rationalization of concrete mix ratios which batches equal volumes of sand and gravel in building projects has been gaining grounds in the Cameroon construction industry. The main objective of thi... In recent years, the rationalization of concrete mix ratios which batches equal volumes of sand and gravel in building projects has been gaining grounds in the Cameroon construction industry. The main objective of this study is therefore to investigate if the concrete produced with rationalized mix ratio can be adopted as conventional mix ratio in terms of minimum required compression strength of concrete for buildings. Specifically this work compared the conventional mix ratio of 350 kg of cement: 400 liters of sand: 800 liters of gravel for a cubic meter and the rationalized batch of 350 kg of cement: 600 liters of sand: 600 liters of 5/15 gravel, 15/25 gravel and a combination of 5/15 + 15/25 gravel. Average compressive tests’results for both the conventional and the rationalized mix ratios were found to meet the minimum compressive strength of 65% at 7 days, 90% at 14 days and 99% at 28 days for gravel size combination 5/15 + 15/25. Single size gravel of 5/15 and 15/25 did not meet the minimum required compressive strength of 20 N/mm<sup>2</sup> for the rationalized mix ratio at 28 days curing based on the minimum compressive strength required, this study arrives at the conclusion that the equal volumes of sand and gravel mix ratio of 350 kg/m<sup>3</sup> of cement: 600 liters of sand: 600 liters of gravel mix ratio can be adopted as a conventional concrete mix ratio for gravel size 5/15 + 15/25. 展开更多
关键词 Conventional concrete rationalized concrete Mix ratio Compressive Strength Equal Volumes of Sand and Gravel
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Slenderness Ratio Influence on the Structural Behavior of Residential Concrete Tall Buildings
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作者 Tarek A. Awida 《Journal of Civil Engineering and Architecture》 2011年第6期527-534,共8页
The main concern of this paper is to study the influence of the building slenderness ratio on the structural behavior of the residential concrete tall buildings aiming to deepen structure and architect designers under... The main concern of this paper is to study the influence of the building slenderness ratio on the structural behavior of the residential concrete tall buildings aiming to deepen structure and architect designers understanding for such type of buildings. The study is emphasized only on Kuwait city design conditions for wind and seismic loadings. The paper presents an actual case study for adding two thirty stories residential towers with two different slenderness ratios to an existing residential complex. Wind loading is considered using both code values and wind tunnel results. Three dimensional finite element techniques through ETABS software are used in conducting analysis for structures presented here. A serviceability study is performed to ensure that buildings have sufficient stability to limit lateral drift and peak acceleration within the acceptable range of occupancy comfort. In addition, an ultimate strength study is carried out to verify that all the structural elements are designed to withstand factored gravity and lateral loads in a safe manner according to the international building codes. Analysis results are presented and discussed. A brief idea about foundation design of the new towers and its connection to the existing foundation is presented. Finally conclusions are summarized as guidelines for the structural professions of concrete residential tall buildings. 展开更多
关键词 Slenderness ratio residential tall buildings finite element reinforced concrete analysis and design.
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Preparation and Optimization of Mix ratio for C50T Girder Manufactured Sand and Concrete
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作者 Honghong Ye Delin Zeng +4 位作者 Yong Yang Xingbo Fan Wei Wang Pingbo Zao Zhusheng Yang 《Frontiers Research of Architecture and Engineering》 2021年第2期16-20,共5页
Considering actual construction conditions of Binchuan-Heqing Highway,this paper provides the C50 mix ratio conforming to engineering requirements by strictly controlling the quality of raw materials,optimizing the de... Considering actual construction conditions of Binchuan-Heqing Highway,this paper provides the C50 mix ratio conforming to engineering requirements by strictly controlling the quality of raw materials,optimizing the design of mix ratio scientifically,preparing superior C50 concrete 0 with manufactured sand,and optimizing the concrete mix ratio based on the adjustment of fly ash replacement,water-cement ratio,polycarboxylate-type water reducer mixing amount,sand ratio,etc.The result indicates that,the water-cement ratio has a great influence on the concrete strength,and if the ratio of coal ash is high in the binding material,the early compressive strength of the concrete will increase slowly. 展开更多
关键词 concrete Mix ratio STRENGTH Water-cement ratio
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Dynamic performance of angle-steel concrete columns under low cyclic loading-I:Experimental study 被引量:21
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作者 郑文忠 计 静 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2008年第1期67-75,共9页
This paper describes low cyclic loading testing of nine angle-steel concrete column (ASCC) specimens. In the tests, the influence of the shear-span ratio, axial compression ratio and shear steel plate ratio on the h... This paper describes low cyclic loading testing of nine angle-steel concrete column (ASCC) specimens. In the tests, the influence of the shear-span ratio, axial compression ratio and shear steel plate ratio on the hysteretic behavior, energy dissipation, strength degradation, stiffness degradation, skeleton curve and ductility of the ASCCs is studied. Based on the test results, some conclusions are presented. The P-A and sectional M -φ hysteretic models for the ASCCs are presented in a companion paper (Zheng and Ji, 2008). 展开更多
关键词 cyclic loading test DUCTILITY hysteretic model angle-steel concrete column shear-span ratio steel platestirrup steel jacketing seismic retrofitting
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Dynamic performance of angle-steel concrete columns under low cyclic loading-II:parametric study 被引量:16
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作者 Zheng Wenzhong Ji Jing 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2008年第2期137-146,共10页
Tests of nine angle-steel concrete column (ASCC) specimens under low cyclic loading are described in a companion paper (Zheng and Ji, 2008). In this paper, the skeleton curves from the numerical simulation are pre... Tests of nine angle-steel concrete column (ASCC) specimens under low cyclic loading are described in a companion paper (Zheng and Ji, 2008). In this paper, the skeleton curves from the numerical simulation are presented, and show good agreement with the test results. Furthermore, parametric studies are conducted to explore the influence of factors such as the axial compression ratio, shear steel plate ratio, steel ratio, prismatic concrete compression strength, yield strength of angle steel and shear span ratio, etc., on the monotonic load-displacement curves of the ASCCs. Based on a statistical analysis of the calculated results, hysteretic models for load-displacement and moment-curvature are proposed, which agree well with the test results. Finally, some suggestions concerning the conformation of ASCCs are proposed, which could be useful in engineering practice. 展开更多
关键词 low cyclic loading angle-steel concrete column shear-span ratio steel plate stirrup hysteretic model
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Research on Flexural Behavior of Coral Aggregate Reinforced Concrete Beams 被引量:9
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作者 MA Hai-yan DA Bo +1 位作者 YU Hong-fa WU Zhang-yu 《China Ocean Engineering》 SCIE EI CSCD 2018年第5期593-604,共12页
Through the flexural behavior test of coral aggregate reinforced concrete beams(CARCB) and ordinary Portland reinforced concrete beams(OPRCB), and based on the parameters of concrete types, concrete strength grades an... Through the flexural behavior test of coral aggregate reinforced concrete beams(CARCB) and ordinary Portland reinforced concrete beams(OPRCB), and based on the parameters of concrete types, concrete strength grades and reinforcement ratios, the crack development, failure mode, midspan deflection and flexural capacity were studied, the relationships of bending moment-midspan deflection, load-longitudinal tensile reinforcement strain, load-maximum crack width were established, and a calculation model for the flexural capacity of CARCB was suggested. The results showed that with the increase in the reinforcement ratio and concrete strength grade, the crack bending moment(Mcr)and ultimate bending moment(Mu) of CARCB gradually increased. The characteristics of CARCB and OPRCB are basically the same. Furthermore, through increasing the concrete strength grade and reinforcement ratio, Mcr/Mu could be increased to delay the cracking of CARCB. As the load increased, crack width(w) would also increase. At the beginning of the loading, w increased slowly. And then it increased rapidly when the load reached to the ultimate load, which then led to beam failure. Meanwhile, with a comprehensive consideration of the effects of steel corrosion on the loss of steel section and the decrease of steel yield strength, a more reasonable calculation model for the flexural capacity of CARCB was proposed. 展开更多
关键词 coral aggregate reinforced concrete beam flexural behavior steel corrosion reinforcement ratio concrete strength calculation model
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Experimental study on the seismic behavior of high strength concrete fi lled double-tube columns 被引量:13
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作者 Qian Jiaru Li Ningbo +1 位作者 Ji Xiaodong Zhao Zuozhou 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第1期47-57,共11页
To study the seismic behavior of high strength concrete fi lled double-tube(CFDT) columns,each consisting of an external square steel tube and an internal circular steel tube,quasi-static tests on eight CFDT column sp... To study the seismic behavior of high strength concrete fi lled double-tube(CFDT) columns,each consisting of an external square steel tube and an internal circular steel tube,quasi-static tests on eight CFDT column specimens were conducted.The test variables included the width-to-thickness ratio(β1) and the area ratio(β2) of the square steel tube,the wall thickness of the circular steel tube,and the axial force(or the axial force ratio) applied to the CFDT columns.The test results indicate that for CFDT columns with a square steel tube with β1 of 50.1 and 24.5,local buckling of the specimen was found at a drift ratio of 1/150 and 1/50,respectively.The lateral force-displacement hysteretic loops of all specimens were plump and stable.Reducing the width-to-thickness ratio of the square steel tube,increasing its area ratio,or increasing the wall thickness of the internal circular steel tube,led to an increased fl exural strength and deformation capacity of the specimens.Increasing the design value of the axial force ratio from 0.8 to 1.0 may increase the fl exural strength of the specimens,while it may also decrease the ultimate deformation capacity of the specimen with β1 of 50.1. 展开更多
关键词 high strength concrete fi lled double-tube(CFDT)column seismic behavior area ratio of the square steel tube width-to-thickness ratio of the square steel tube axial force ratio quasi-static test
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