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Study on Durability of Recycled Aggregate Concrete in High-Temperature and Complex Environments
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作者 Xiaoqing Hu Yao Tong +1 位作者 Xuan Min Rongchong Xu 《Journal of World Architecture》 2024年第5期66-71,共6页
Recycled aggregate concrete refers to a new type of concrete material made by processing waste concrete materials through grading,crushing,and cleaning,and then mixing them with cement,water,and other materials in a c... Recycled aggregate concrete refers to a new type of concrete material made by processing waste concrete materials through grading,crushing,and cleaning,and then mixing them with cement,water,and other materials in a certain gradation or proportion.This type of concrete is highly suitable for modern construction waste disposal and reuse and has been widely used in various construction projects.It can also be used as an environmentally friendly permeable brick material to promote the development of modern green buildings.However,practical applications have found that compared to ordinary concrete,the durability of this type of concrete is more susceptible to high-temperature and complex environments.Based on this,this paper conducts theoretical research on its durability in high-temperature and complex environments,including the current research status,existing problems,and application prospects of recycled aggregate concrete’s durability in such environments.It is hoped that this analysis can provide some reference for studying the influence of high-temperature and complex environments on recycled aggregate concrete and its subsequent application strategies. 展开更多
关键词 recycled aggregate concrete Construction engineering High-temperature and complex environment DURABILITY
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Prediction Model-based Multi-objective Optimization for Mix-ratio Design of Recycled Aggregate Concrete
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作者 CHEN Tao WU Di YAO Xiaojun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第6期1507-1517,共11页
The prediction model for mechanical properties of RAC was established through the Bayesian optimization-based Gaussian process regression(BO-GPR)method,where the input variables in BO-GPR model depend on the mix ratio... The prediction model for mechanical properties of RAC was established through the Bayesian optimization-based Gaussian process regression(BO-GPR)method,where the input variables in BO-GPR model depend on the mix ratio of concrete.Then the compressive strength prediction model,the material cost,and environmental factors were simultaneously considered as objectives,while a multi-objective gray wolf optimization algorithm was developed for finding the optimal mix ratio.A total of 730 RAC datasets were used for training and testing the predication model,while the optimal design method for mix ratio was verified through RAC experiments.The experimental results show that the predicted,testing,and expected compressive strengths are nearly consistent,illustrating the effectiveness of the proposed method. 展开更多
关键词 recycled coarse aggregate mix ratio multi-objective optimization prediction model compressive strength
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Compressive Performance of Fiber Reinforced Recycled Aggregate Concrete by Basalt Fiber Reinforced Polymer-Polyvinyl Chloride Composite Jackets 被引量:1
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作者 Zhijie Fan Huaxin Liu +2 位作者 Genjin Liu Xuezhi Wang Wenqi Cui 《Journal of Renewable Materials》 SCIE EI 2023年第4期1763-1791,共29页
The development of recycled aggregate concrete(RAC)provides a new approach to limiting the waste of natural resources.In the present study,the mechanical properties and deformability of RACs were improved by adding ba... The development of recycled aggregate concrete(RAC)provides a new approach to limiting the waste of natural resources.In the present study,the mechanical properties and deformability of RACs were improved by adding basalt fibers(BFs)and using external restraints,such as a fiber-reinforced polymer(FRP)jacket or a PVC pipe.Samples were tested under axial compression.The results showed that RAC(50%replacement of aggregate)containing 0.2%BFs had the best mechanical properties.Using either BFs or PVC reinforcement had a slight effect on the loadbearing capacity and mode of failure.With different levels of BFs,the compressive strengths of the specimens reinforced with 1-layer and 3-layer basalt fiber reinforced polymer(BFRP)increased by 6.7%–10.5%and 16.5%–23.7%,respectively,and the ultimate strains increased by 48.5%–80.7%and 97.1%–141.1%,respectively.The peak stress of the 3-layer BFRP-PVC increased by 42.2%,and the ultimate strain improved by 131.3%,relative to the control.This reinforcement combined the high tensile strength of BFRP,which improved the post-peak behavior,and PVC,which enhanced the structural durability.In addition,to investigate the influence of the various constraints on compressive behavior,the stress-strain response was analyzed.Based on the analysis of experimental results,a peak stress-strain model and an amended ultimate stress-strain model were proposed.The models were verified as well;the result showed that the predictions from calculations are generally consistent with the experimental data(error within 10%).The results of this study provide a theoretical basis and reference for future applications of fiber-reinforced recycled concrete. 展开更多
关键词 Basalt fiber reinforced polymer polyvinyl chloride recycled aggregate concrete axial compression performance stress-strain relationships stress-strain model
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Effect of High Temperature Curing on the Frost Resistance of Recycled Aggregate Concrete and the Physical Properties of Second-Generation Recycled Coarse Aggregate under Freeze-Thaw Cycles 被引量:1
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作者 Xintong Chen Pinghua Zhu +2 位作者 Xiancui Yan Lei Yang Huayu Wang 《Journal of Renewable Materials》 SCIE EI 2023年第6期2953-2967,共15页
With the emphasis on environmental issues,the recycling of waste concrete,even recycled concrete,has become a hot spot in the field of architecture.But the repeated recycling of waste concrete used in harsh environmen... With the emphasis on environmental issues,the recycling of waste concrete,even recycled concrete,has become a hot spot in the field of architecture.But the repeated recycling of waste concrete used in harsh environments is still a complex problem.This paper discusses the durability and recyclability of recycled aggregate concrete(RAC)as a prefabricated material in the harsh environment,the effect of high-temperature curing(60℃,80℃,and 100℃)on the frost resistance of RAC and physical properties of the second generation recycled coarse aggregate(RCA_(2))of RAC after 300 freeze-thaw cycles were studied.The frost resistance of RAC was characterized by compressive strength,relative dynamic elastic modulus,and mass loss.As the physical properties of RCA_(2),the apparent density,water absorption,and crushing value were measured.And the SEM images of RAC after 300 freeze-thaw cycles were shown.The results indicated that the frost resistance of RAC cured at 80℃ for 7 days was comparable to that cured in the standard condition(cured for 28 days at 20℃±2℃ and 95%humidity),and the RAC cured at 100℃ was slightly worse.However,the frost resistance of RAC cured at 60℃ deteriorated seriously.The RAC cured at 80℃ for 7 days is the best.Whether after the freeze-thaw cycle or not,the RCA that curd at 60℃,80℃,and 100℃ for 7 days can also meet the requirements of Grade III RCA and be used as the aggregate of non-bearing part of prefabricated concrete components.RCA_(2) which is cured at 80℃ for 7 days had the best physical properties. 展开更多
关键词 Freeze-thaw cycles curing condition recycled aggregate concrete second-generation recycled coarse aggregate
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Effect of Recycled Aggregate and Slag as Substitutes for Natural Aggregate and Cement on the Properties of Concrete:A Review
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作者 Peng Zhang Wenshuai Wang +1 位作者 Yuanxun Zheng Shaowei Hu 《Journal of Renewable Materials》 SCIE EI 2023年第4期1853-1879,共27页
Using recycled aggregate(RA)and slag instead of natural aggregate(NA)and cement can reduce greenhouse gas emissions(GHGE)and achieve effective waste recovery.In recent years,RA has been widely used to replace NA in co... Using recycled aggregate(RA)and slag instead of natural aggregate(NA)and cement can reduce greenhouse gas emissions(GHGE)and achieve effective waste recovery.In recent years,RA has been widely used to replace NA in concrete.Every year,several researchers conduct investigations on the mechanical performance and durability of recycled aggregate concrete(RAC).Due to the loose and porous material properties of RA,the mechanical properties and durability of RAC,such as strength,carbonation resistance,permeability resistance and chloride ion penetration resistance,are greatly reduced compared with natural aggregate concrete.In contrast,concrete containing slag instead of NA and cement generally improved the strength of concrete and reduced the internal porosity of materials.Herein,we discuss the effects of RA and slag on the workability,compressive strength,splitting tensile strength,ultrasonic pulse velocity(UPV)value,and elastic modulus of concrete.The relationships between the compressive strength and the splitting tensile strength,UPV value,and elastic modulus are discussed,and the optimal substitution method is proposed.In addition,various equations for calculating the compressive strength of concrete based on performance factors related to the compressive strength are summarized. 展开更多
关键词 recycled aggregate concrete slag concrete WORKABILITY mechanical performance prediction equations
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Mechanical and Permeability Analysis and Optimization of Recycled Aggregate Pervious Concrete Based on Response Surface Method
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作者 Fan Li Xin Cai +2 位作者 Yanan Zhang Xingwen Guo Minmin Jiang 《Journal of Renewable Materials》 SCIE EI 2023年第4期1745-1762,共18页
In this paper,the effects of different influencing factors and factor interaction on the compressive strength and permeability of recycled aggregate pervious concrete(RAPC)were studied based on the response surface me... In this paper,the effects of different influencing factors and factor interaction on the compressive strength and permeability of recycled aggregate pervious concrete(RAPC)were studied based on the response surface method(RSM).By selecting the maximum aggregate size,water cement ratio and target porosity as design variables,combined with laboratory tests and numerical analysis,the influences of three factors on the compressive strength and permeability coefficient of RAPC were revealed.The regression equation of compressive strength and permeability coefficient of recycled aggregate pervious concrete were established based on RSM,and the response surface model was optimized to determine the optimal ratio of RAPC under the conditions of meeting the mechanical and permeability properties.The results show that the mismatch item of the model is not significant,the model is credible,and the accuracy and reliability of the test are high,but the degree of uncorrelation between the test data and the model is not obvious.The sensitivity of the three factors to the compressive strength is water cement ratio>maximum coarse aggregate particle size>target porosity,and the sensitivity to the permeability coefficient is target porosity>maximum coarse aggregate particle size>water cement ratio.The absolute errors of the model prediction results and the model optimization results are 1.28 MPa and 0.19 mm/s,and the relative errors are 5.06%and 4.19%,respectively.With high accuracy,RSM can match the measured results of compressive strength and permeability coefficient of RAPC. 展开更多
关键词 recycled aggregate pervious concrete(RAPC) response surface method(RSM) MECHANICAL PERMEABILITY OPTIMIZATION
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Experimental Behavior of Recycled Aggregate Concrete Filled Steel Tubular Columns
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作者 Thirumalai R Suresh Babu S 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第6期1414-1417,共4页
During the modernization or rehabilitation activity,the demolished structural waste causes large soil pollution and unavailability of natural aggregate is the big concern for the construction industry.Therefore,this m... During the modernization or rehabilitation activity,the demolished structural waste causes large soil pollution and unavailability of natural aggregate is the big concern for the construction industry.Therefore,this manuscript deals with the Composite Steel Circular Column(CSCC)with Recycled Aggregate concrete(RAC)as infill is partly used,with the replacement of 25%and 50%in M30 grade of Concrete.And internal reinforcement steel is fully replaced by rolled steel tubes(circular and square)with varied thickness,ISA-unequal angle.Around 14 specimens are cast and examined under axial load for analysis of the deflection characteristics,the load-bearing capacity along with its buckling behavior.The experimental values are estimated through LVDT(linear variable differential transducer)at 3-phase.The curve of load-deflection is drawn with the load pattern.From the date interpretation,it is found column made of 50%-RAC has more than 25%-RAC. 展开更多
关键词 composite steel circular column(CSCC) recycled aggregate concrete(RAC) ISAinternational standard angle LVDT(linear variable differential transducer)
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Experimental Investigation on Compressive Properties of Fiber Recycled Aggregate Concrete
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作者 Guiwu Lin Kaige Liu +2 位作者 Yuliang Chen Yunpeng Ji Rui Jiang 《Journal of Renewable Materials》 EI 2023年第11期3957-3975,共19页
This paper presents an experimental study to explore the compressive properties of fiber recycled aggregate concrete.A total of 75 specimens with the replacement rate of recycled coarse aggregate and fiber type were c... This paper presents an experimental study to explore the compressive properties of fiber recycled aggregate concrete.A total of 75 specimens with the replacement rate of recycled coarse aggregate and fiber type were conducted under a uniaxial compressive test.The failure modes,stress-strain whole curves,peak stress,peak strain,and energy dissipation capacity were systematically observed and revealed.Test results indicate that steel fiber has the best modification effect on energy dissipation capacity and the toughness index of recycled concrete,corresponding to the enhancement of 81.75% and 22.90% on average.The addition of polyvinyl alcohol fiber can effectively improve the compressive strength and energy dissipation capacity of recycled aggregate concrete by 28.49% and 29.43% on average,respectively.The compressive strength and energy dissipation capacity of recycled aggregate concrete is increased by an average of 16.5% and 24.4% by incorporating carbon fiber.The energy dissipation capacity of recycled aggregate concrete is increased by an average of 13.5% with the incorporation of polypropylene fiber.However,the addition of carbon fiber results in a slight reduction of toughness by 16.97%,and the effect of polyvinyl alcohol fiber on the energy dissipation capacity is limited.Besides,with the increase in replacement rate,the compressive strength and the energy dissipation capacity of recycled coarse aggregate concrete with fiber decreased,and toughness first decreased and then increased.Finally,based on the analysis of test data,a segment-based stress-strain model of fiber recycled aggregate concrete was proposed,which shows good agreement with the test results. 展开更多
关键词 recycled aggregate concrete FIBER compressive properties energy dissipation TOUGHNESS
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Multi-Scale Investigation on Concrete Prepared with Recycled Aggregates from Different Parent Concrete 被引量:2
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作者 Zhenhua Duan Nv Han +1 位作者 Amardeep Singh Jianzhuang Xiao 《Journal of Renewable Materials》 SCIE EI 2020年第11期1375-1390,共16页
Recycled aggregates(RA)are frequently obtained from various unknown sources,which caused variation in properties among recycled aggregates concrete(RAC).This paper investigated the macro and microscopic properties o... Recycled aggregates(RA)are frequently obtained from various unknown sources,which caused variation in properties among recycled aggregates concrete(RAC).This paper investigated the macro and microscopic properties of RAC prepared with RAs originated from different parent concretes with 90-day strength ranging from 30 MPa to 100 MPa.These parent concretes were prepared in advance and crushed to produce RA of distinct qualities.The attached mortar content can reach up to 69%in the concrete with highest strength grade.The microscopic investigation on different RAC was conducted with the X-ray Micro-Computed Tomography scanning technique and image process.Experimental results showed that the properties of RA derived from various parent concrete varied because of the amount of residual mortar.The development of mechanical properties and chloride-ion penetration of RACs all followed a binomial trend with the strength grades of the parent concrete because of the different quantity and quality of RAs. 展开更多
关键词 recycled aggregate recycled aggregate concrete parent concrete mechanical property CT scanning image process
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The Compression-deformation Behaviour of Concrete with Various Modified Recycled Aggregates 被引量:1
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作者 杜婷 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2005年第2期127-129,共3页
Modified recycled aggregates were prepared with three different cement-admixture grouts. The physical properties, such as water absorption, apparent density, crushing index, slump and compressive strength of the recyc... Modified recycled aggregates were prepared with three different cement-admixture grouts. The physical properties, such as water absorption, apparent density, crushing index, slump and compressive strength of the recycled aggregate and the recycled concretes were tested, and the tests for the compression-deformation behavior of the concretes were also performed. The experimental results show that the cement-Kim powder grout is satisfied for enhancing the recycled concrete, and the modification of the recycled aggregate with the grouts can improve the toughness and the deformation ability of the concretes. 展开更多
关键词 recycled aggregates concrete recycled aggregates ultrafine mineral powder
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Compressive Strength, Pore Size Distribution and Chloride-ion Penetration of Recycled Aggregate Concrete Incorporating Class-F Fly Ash 被引量:13
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作者 寇世聪 C S Poon 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第4期130-136,共7页
The effects of fly ash on the compressive strength, pore size distribution and chloride-ion penetration of recycled aggregate concrete were investigated. Two series of concrete mb:tures were prepared. The concrete mi... The effects of fly ash on the compressive strength, pore size distribution and chloride-ion penetration of recycled aggregate concrete were investigated. Two series of concrete mb:tures were prepared. The concrete mixtures in series I had a water-to-binder ratio and a cement content of 0.55 and 410 kg/ m^3 , respectively. The concrete rnixtures in series II had a water-to-binder ratio and a cement content of 0.45 and 400 kg/ ml respectively. Recycled aggregate was ased as 20% , 50% , and 100% replacements of natural coarse aggregate in the concrete mixtures in both series. In cutdition, fly ash was used as 0% , 25% and 35% by weight replacements of cement. The results show that the compressive strengths of the concrete decreased as the recycled aggregate and the fly ash contents increased. The total porosity and average porosity diameter of the concrete increased us the recycled aggregate content increased. Furtherrruore , an increase in the recycled aggregate content decreased the resistance to chloride ion penetration. Nevertheless, the replacement of cement by 25% fly ush improved the resistance to chloride ion penetration and pore diameters and reduced the total porosity of the recycled aggregate concrete. 展开更多
关键词 durability properties recycled aggregate concrete fly ash
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Freeze-thaw Durability of Recycled Aggregate Concrete:An Overview 被引量:6
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作者 LUAN Haoxiang WU Jin PAN Jiayu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2021年第1期58-69,共12页
The characteristics of surface appearances,mass loss,relative dynamic modulus of elasticity and strength loss of different recycled aggregate concretes(RAC) exposed to freeze-thaw cycles were analyzed.It was found tha... The characteristics of surface appearances,mass loss,relative dynamic modulus of elasticity and strength loss of different recycled aggregate concretes(RAC) exposed to freeze-thaw cycles were analyzed.It was found that the freeze-thaw resistance of RAC could be determined by the recycled aggregate compositions and admixtures.Both the saturation degree and the air void structure were the key factors influencing the freeze-thaw damage on concrete.Some major proposed freeze-thaw deterioration mechanisms were utilized to interpret the freeze-thaw damage on recycled aggregate concrete.Meanwhile,some potential measures to enhance the freeze-thaw resistance of concrete were summarized and discussed. 展开更多
关键词 recycled aggregate concrete freeze-thaw durability aggregate composition deterioration mechanism improvement measures
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Effect of flexural loading on degradation progress of recycled aggregate concrete subjected to sulfate attack and wetting-drying cycles 被引量:4
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作者 Zhao Yasong Gao Jianming +1 位作者 Qi Bing Liu Chuanbei 《Journal of Southeast University(English Edition)》 EI CAS 2019年第1期83-88,共6页
The degradation progress of recycled aggregate concrete(RAC) subjected to sulfate attack under wetting-drying cycles and flexural loading is studied. Three different stress ratios(0, 0.3 and 0.5) were applied in this ... The degradation progress of recycled aggregate concrete(RAC) subjected to sulfate attack under wetting-drying cycles and flexural loading is studied. Three different stress ratios(0, 0.3 and 0.5) were applied in this test. The variations of relative dynamic elastic modulus Erd and water-soluble SO2-4 contents in RAC were used to evaluate degradation progress. The changes in mineral products and microstructures of interior concrete were investigated by means of X-ray diffraction(XRD), the environmental scanning electron microscope(ESEM) and X-ray computed tomography(X-CT). The results indicate that flexural loading accelerates the degradation of RAC under sulfate attack and wetting-drying cycles by expediting the transmission of SO2-4 into interior concrete. Furthermore, the accelerated effect of flexural loading is more obvious with the increase of stress ratio, that is because higher stress ratios can accelerate the extension of microcracks and generate more channels for the transmission of SO2-4. Also, more expansive products(gypsum and ettringite) are generated by the reaction of Ca(OH)2 with SO2-4, which can further accelerate the degradation of RAC. 展开更多
关键词 recycled aggregate concrete DEGRADATION sulfate attack flexural loading wetting-drying cycles
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Effects of Polypropylene Fibers on the Physical and Mechanical Properties of Recycled Aggregate Concrete 被引量:4
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作者 Pierre Matar Gérard-Philippe Zéhil 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第6期1327-1344,共18页
The viability of using polypropylene fibers(PPF) in concrete was largely studied. Yet, few of the existing research studies investigated the effects of PPF on the properties of concrete containing recycled concrete ag... The viability of using polypropylene fibers(PPF) in concrete was largely studied. Yet, few of the existing research studies investigated the effects of PPF on the properties of concrete containing recycled concrete aggregate(RCA). Mixes with different RCA replacement ratios and different PPF content were designed and tested. The test results showed that the addition of PPF did not change significantly the compressive strength and the density of the concrete, but slightly decreased its modulus of elasticity and Poisson’s ratio. The drop in the splitting tensile strength and the flexural strength due to RCA inclusions was to a large extent compensated by the PPF addition. The water absorption decreased and the percent voids increased with increased PPF addition. Correlations between the RCA content, the PPF content and the properties of concrete were studied. Useful regression models were proposed to predict the properties of concrete in relevant ranges of RCA and PPF content. 展开更多
关键词 CONCRETE recycled aggregate fiber reinforcement physical properties mechanical properties
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Improving performance of recycled aggregate concrete with superfine pozzolanic powders 被引量:3
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作者 王海龙 王俊杰 +1 位作者 孙晓燕 金伟良 《Journal of Central South University》 SCIE EI CAS 2013年第12期3715-3722,共8页
Phosphorous slag (PHS), ground granulated blast-furnace slag (GGBS) and fly ash (FA) were used as replacements of Portland cement to modify the microstruc^xe of recycled aggregate concrete (RAC). A new manufac... Phosphorous slag (PHS), ground granulated blast-furnace slag (GGBS) and fly ash (FA) were used as replacements of Portland cement to modify the microstruc^xe of recycled aggregate concrete (RAC). A new manufacturing method named "W3T4" was proposed to improve the performances of interracial transition zone (ITZ) between recycled aggregate and mortar. The mechanical properties and the durability of RAC were tested, which show that this new manufacturing method improves the properties of RAC, and the GGBS with finest size makes a great contribution to the performance of RAC due to its better filling effect and much earlier pozzolanic reaction. Combined with GGBS, the effects of PHS on the retardation of setting time can be alleviated and the synergistic effect helps to make a more compact RAC. For the RAC with 25% of the recycled aggregate (RA) replacement and 10% PHS + 10% GGBS additives, the compressive strength increases by 25.4%, but the permeability decreases by 64.3% with respect to the reference concrete made with nature aggregates. The micro-mechanisms of these improvements were investigated by the scanning electron microscope (SEM). The SEM images show that the new manufacturing method, adding superfine pozzolanic powders and super-plasticizer benefits, makes a much denser ITZ in RAC. 展开更多
关键词 recycled aggregate concrete superfine pozzolanic powders manufacturing method DURABILITY MICROSTRUCTURE
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Bond Behavior between BFRP Bars and Hybrid Fiber Recycled Aggregate Concrete after High Temperature 被引量:3
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作者 Boheng Zhu Huaxin Liu +3 位作者 Genjin Liu Abasal Hussain Xiaofei Zhang Xuezhi Wang 《Journal of Renewable Materials》 SCIE EI 2021年第3期507-521,共15页
The aim of this study is to improve the bond performance of basalt fiber reinforced polymer(BFRP)bars and recycled aggregate concrete(RAC)after being exposed to high temperatures.The bond behavior(failure modes,bond s... The aim of this study is to improve the bond performance of basalt fiber reinforced polymer(BFRP)bars and recycled aggregate concrete(RAC)after being exposed to high temperatures.The bond behavior(failure modes,bond strength,bond stress-slip curves)between BFRP bars and hybrid fiber recycled aggregate concrete(HFRAC)after being exposed to temperatures ranging from 20℃up to 500℃was studied by using pull-out tests.The effect of high temperatures on mechanical properties of concrete(compressive strength,splitting tensile strength)and tensile strength of BFRP bars was also investigated.The bond strength decreased as the temperature increased and the drop of bond strength between RAC and BFRP bar was larger than that between HFRAC and BFRP bar.As the temperature rises,the key factor affecting the bond strength was gradually transformed from concrete strength to BFRP bar strength.The relationship between bond stress and slip in the dimensionless bond stress-slip ascending section was established,which was in good agreement with the experimental results. 展开更多
关键词 High temperature BFRP bar hybrid fiber recycled aggregate concrete bond performance
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The Complete Stress-strain Curve of Recycled Aggregate Concrete under Uniaxial Compression Loading 被引量:3
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作者 杜婷 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第5期862-865,共4页
The mechanical performance of recycled aggregate concrete (RAC) is investigated. An experiment on the complete stress-strain curve under uniaxial compression loading of RAC is carried out. The experimental results i... The mechanical performance of recycled aggregate concrete (RAC) is investigated. An experiment on the complete stress-strain curve under uniaxial compression loading of RAC is carried out. The experimental results indicate that the peak stress, peak strain, secant modulus of the peak point and original point increase with the strength grade of RAC enhanced. On the contrary, the residual stress of RAC decreases with the strength grade enhancing, and the failure of RAC is often broken at the interface between the recycled aggregate and the mortar matrix. Finally, the constitutive model of stress-strain model of RAC has been constituted, and the results from the constitutive model of stress-strain meet the experiment results very well. 展开更多
关键词 recycled aggregate concrete the complete stress-strain curve constitutive model uniaxial compression loading
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Study of the seismic response of a recycled aggregate concrete frame structure 被引量:2
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作者 Wang Changqing Xiao Jianzhuang 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2013年第4期669-680,共12页
Based on six-degree-of-freedom three-dimensional shaking table tests, the seismic response of a recycled aggregate concrete (RAC) frame was obtained. The analysis results indicate that the maximum story shear force ... Based on six-degree-of-freedom three-dimensional shaking table tests, the seismic response of a recycled aggregate concrete (RAC) frame was obtained. The analysis results indicate that the maximum story shear force and overturning moment reduce proportionally along the height of the model under the same earthquake wave. The story shear force, base shear coefficient and overturning moment of the structure increase progressively as the acceleration amplitude increases. The base shear coefficient is primarily controlled by the peak ground acceleration (PGA). The relationships between the PGA and the shear coefficient as well as between the PGA and the dynamic amplification factor are obtained by mathematical fitting. The dynamic amplification factor decreases rapidly at the elastic-plastic stage, but decreases slowly with the development of the elastic-plasticity stage. The results show that the RAC frame structure has reasonable deformability when compared with natural aggregate concrete frame structures. The maximum inter-story drift ratios of the RAC frame model under frequent and rare intensity 8 test phases are 1/266 and 1/29, respectively, which are larger than the allowable value of 1/500 and 1/50 according to Chinese seismic design requirements. Nevertheless, the RAC frame structure does not collapse under base excitations with PGAs from 0.066 g up to 1.170 g. 展开更多
关键词 recycled aggregate concrete (RAC) frame structure seismic response shear coefficient dynamicamplification factor
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Effects of Recycled Aggregate Content on Pervious Concrete Performance 被引量:2
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作者 Lei Guo Zi Guan +4 位作者 Lixia Guo Weiping Shen Zhilong Xue Pingping Chen Mingru Li 《Journal of Renewable Materials》 SCIE EI 2020年第12期1711-1727,共17页
A recycled aggregate(RA)was prepared by crushing and sieving demolished discarded concrete pavements and was subsequently tested and analyzed to determine its various physical properties.On this basis,pervious concre... A recycled aggregate(RA)was prepared by crushing and sieving demolished discarded concrete pavements and was subsequently tested and analyzed to determine its various physical properties.On this basis,pervious concrete(PC)mix proportions were designed.Coarse RA particles with sizes of 5–10 and 10–20 mm were selected.Concrete specimens were prepared with a water–cement ratio of 0.3,an aggregate–cement ratio of 4.5,the substitute rates of RA with 0,25%,50%,75%and a single-/double-gap-graded RA mix(mass ratio of particles with sizes of 5–10 mm to particles with sizes of 10–20 mm:1:1,1:2,2:1,2:3 and 3:2).Various properties of the RA-containing PC(RPC)were determined by analyzing the compressive strength,splitting tensile strength,effective porosity,permeation coefficient and impact and abrasion resistance of the specimens.The results showed the following:The density of the RPC decreased with an increasing RA replacement ratio.The density of the RPC prepared with a double-gapgraded RA mix was lower than that prepared with a single-gap-graded RA(particle size:10–20 mm)mix.The permeation coefficient of the RPC increased with increasing porosity.The splitting tensile strength of the RPC was positively correlated with its compressive strength.The compressive strength of the RPC decreased with increasing porosity.The regression analysis showed that the impact and abrasion resistance of the RPC increased with increasing compressive strength.In addition,all of the RPC specimens met the strength and permeation requirements.This study can provide theoretical support for the application of RPC. 展开更多
关键词 recycled aggregate recycled pervious concrete STRENGTH PERMEABILITY wear resistance mix proportion
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Mechanical Properties and ITZ Microstructure of Recycled Aggregate Concrete Using Carbonated Recycled Coarse Aggregate 被引量:7
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作者 伍君勇 张云升 +2 位作者 ZHU Pinghua FENG Jincai 胡坤 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2018年第3期648-653,共6页
The effect of carbonation treatment and mixing method on the mechanical properties and interfacial transition zone(ITZ) properties of recycled aggregate concrete(RAC) was investigated. Properties of recycled concr... The effect of carbonation treatment and mixing method on the mechanical properties and interfacial transition zone(ITZ) properties of recycled aggregate concrete(RAC) was investigated. Properties of recycled concrete aggregate(RCA) were tested firstly. Then, five types of concretes were made and slump of fresh concrete was measured immediately after mixing. Compressive strength and splitting tensile strength of hardened concrete were measured at 28 d. Meanwhile, the microstructure of RAC was analyzed by backscattered electron(BSE) image. It was found that the water absorption ratio of carbonated recycled concrete aggregate(CRCA) was much lower when compared to the untreated RCA. Comparatively, the apparent density of CRCA was not significantly modified. The concrete strength results indicate that the mix CRAC-2 prepared with CRCA by adopting two-stage mixing approach shows the highest compressive strength value compared to the other mixes. The microstructural analysis demonstrate that the mix CRAC-2 has a much denser old ITZ than the untreated RAC because of the chemical reaction between CO2 and the hydration products of RCA. This study confirms that the ITZ microstructure of RAC can be efficiently modified by carbonation treatment of RCA and encourages broadening the application of construction and demolition wastes. 展开更多
关键词 recycled aggregate concrete compressive strength interfacial transition zone carbonation treatment two-stage mixing approach back scattered electron
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