Study on the Recycled Concrete Beam’s Stiffness

2012 ◽  
Vol 193-194 ◽  
pp. 1361-1364
Author(s):  
Fang Yu ◽  
Can Bin Yin ◽  
Min Jiang

The intent of this paper is to investigate the flexural behavior of 4 recycled concrete simply-supported beams with same percentage of reinforntage of reinforcement and axial compressive strength but different replacement ratio of recycled aggregates.Besides the flexural capacity of normal section,the characteristics of both deflection and cracking are analyzed.Based on the experiment results,the following conclusions are drawn.In bending,the recycled concrete beam also has elastic,cracking,yield and ultimate point.The ultimate moment of recycled concrete beam can be estimated by the formula suggested by present code.

2010 ◽  
Vol 29-32 ◽  
pp. 543-548 ◽  
Author(s):  
Wen Hui Bai ◽  
Bin Xiang Sun

In order to investigate flexural behavior of simply-supported beam using recycled coarse aggregate concrete, the difference of the component normal section stress distortion performance and failure characteristic between the recycled concrete beam and the normal concrete beam is researched. The approaches of testing the flexural behavior of 6 recycled course aggregate beams with the same section size, different replacement ratio of recycled coarse aggregate (0%, 50%, 70% and 100%) and different percentage reinforcement (0.68%, 0.89% and 1.13%). Based on the experimental the following conclusions are draw. There are also 4 phases of elasticity, cracking, yield and ultimate during the stress course of recycled concrete beam component normal section stress; the average strain measured on cross-section obliges to the plane section assumption; the characteristics of stress distortion and destruction of recycled concrete beam are basically the same as those of the normal concrete beam. Under same conditions, the cracking moment and the ultimate flexural carrying capability of recycled concrete beam is almost the same as those of normal concrete beam. The deformation of recycled concrete beam is larger than concrete beam. The conclusion of the paper is that it is still feasible to calculate the ultimate bending moment, cracking moment, and the biggest crack width of recycled concrete beam according to the formula in China Concrete Structure Design Code, but the deflection formula needs to be adjusted.


2012 ◽  
Vol 174-177 ◽  
pp. 1277-1280 ◽  
Author(s):  
Hai Yong Cai ◽  
Min Zhang ◽  
Ling Bo Dang

Compressive strengths of recycled aggregate concrete(RAC) with different recycled aggregates(RA) replacement ratios at 7d, 28d, 60d ages are investigated respectively. Failure process and failure mode of RAC are analyzed, influences on compressive strength with same mix ratio and different RA replacement ratios are analyzed, and the reason is investigated in this paper. The experimental results indicate that compressive strength of recycled concrete at 28d age can reach the standard generally, it is feasible to mix concrete with recycled aggregates, compressive strength with 50% replacement ratio is relatively high.


2013 ◽  
Vol 368-370 ◽  
pp. 1090-1094
Author(s):  
Yuan Xu ◽  
Xiao Ping Wang ◽  
Juan Cheng ◽  
Dong Wang

Study four factors - water consumption , water-cement ratio , recycled fine aggregate replacement ratio of recycled coarse aggregate replacement rate - affect the regularity of the load-bearing hollow block compressive strength of recycled concrete by orthogonal test method , the test showed that , water consumption factors affect the compressive strength of recycled concrete block design with than the emphasis on the control of water consumption . Under the test conditions , the optimum mixture ratio of recycled concrete load-bearing block : water consumption of 160 kg / m 3 , the water cement ratio 0.45 , recycled fine aggregate replacement ratio of 30% recycled coarse aggregate replacement ratio of 30% .


2020 ◽  
Vol 6 (3) ◽  
pp. 271
Author(s):  
Mahmud Kori Effendi

Reinforced concrete is one of the most widely used building materials in Indonesia due to its workability, easiness, and reasonable price. Meanwhile, it is very important to understand the response of these elements during the loading process to ensure the development of an effective structure and one of the most effective numerical methods for reinforced concrete elements is the Finite Element Analysis (FEA). This study was, therefore, conducted to investigate the flexural behavior of reinforced concrete beam using a nonlinear finite element analysis through the application of the MSC MARC/MENTAT software program. This involved the use of a solid element to represent concrete while the truss bar was applied for reinforcing steel after which multi-linear and bilinear models were considered for the two elements respectively while embedded reinforcement model was applied to model the rebar. Moreover, the beam model was also studied and compared with experimental data from previous literature. The result showed the load-deflection to have significantly increased due to an increment in the steel reinforcement yield strength. The same was also observed for the concrete compressive strength while a decrease was recorded in deflection due to the reduction in the compressive strength because the strain was reaching the crushing value. Furthermore, the concrete tension model was found to be the same with the experimental results with the tensile strength observed to have lost its strength after reaching the tensile stress while the contact behavior of the modeled reinforced concrete beam showed the existence of a slip at the support and loading points.


2012 ◽  
Vol 598 ◽  
pp. 635-639
Author(s):  
Zhao Hua Du ◽  
Jie Wang

In this paper, the mixture ratio of recycled concrete and its fundamental mechanics properties have been researched by experiments, which include the mechanical properties of recycled aggregate, the optimum mix design of the recycled concrete, compressive strength tests on concrete specimens using the broken abandoned concrete rubbles as recycled coarse aggregate, the replacement ratios of recycled coarse aggregate by mass to the natural coarse aggregate are 0, 0.3, 0.5, 0.70 and 1.0 respectively. The influences of the replacement ratio of recycled coarse aggregate by mass to the fundamental properties of the recycled concrete such as the compressive strength,and the elastic modulus are discussed and analyzed.and the optimum replacement ratio of recycled coarse aggregate by mass is suggested. These may be references to the applications of recycled concrete in engineering.


2011 ◽  
Vol 295-297 ◽  
pp. 958-961
Author(s):  
Ai Jiu Chen ◽  
Jing Wang ◽  
Zhan Fang Ge

At present, there are not any systematic researches on the fundamental performance of recycled concrete(RC). Thus it incites the inadequate confidence for the usage of RC. In this thesis, four different kinds of RC whose strength are C20、C25、C30、C35 respectively,are made using various mixing proportion. Then the influence rule of different recycled aggregate mixture quantities is drawn out, which consists the impacts on compressive strength, axial compressive strength, splitting strength, elastic modulus as well as the bending strength of RC. Meanwhile, the relation between the cubic compressive strength and the splitting strength, elastic modulus, axial compressive strength, bending strength is imitated, which provides study basis for the using of wasted concrete.


2013 ◽  
Vol 357-360 ◽  
pp. 1282-1285
Author(s):  
Hai Yong Cai ◽  
Li Bin Fu ◽  
Ling Bo Dang

Influence of replacement ratio and water-cement ratio on the recycled concrete mechanical properties were analyzed by testing the compressive strength and tensile strength of the recycled concrete. Results show that the mechanical properties of recycled concrete, compared with common concrete, can meet the requirements of the project. Water-cement ratio has great influence on compressive strength and tensile strength, replacement ratio has obvious influence on compressive strength but little on tensile.


2011 ◽  
Vol 299-300 ◽  
pp. 135-138 ◽  
Author(s):  
Yan Dong Jia ◽  
Zheng Wei Zhou ◽  
Yan Dong Qu ◽  
Ao Shuang Tian

Comparative experiments on the ordinary steel fiber recycled concrete (SFRC) and roller compacted SFRC were carried out to research the fracture properties of roller compacted SFRC. The results show that compressive strength, fracture toughness and fracture energy of roller compacted SFRC increase with the increase of fiber volume fraction. Compressive strength increase with the increase of recycled aggregate replacement rate and fracture toughness decrease, however, Crack tip opening displacement has little changes and fracture energy features fluctuation with the replacement ratio of recycled coarse aggregates increasing. The rolled formed layers have significant influence on the fracture properties of SFRC. The fracture toughness of roller compacted SFRC is generally lower than ordinary SFRC and compressive strength is higher than ordinary steel fiber concrete for the same aggregate replacement ratio and fiber volume fraction. Fracture energy of roller compacted SFRC is higher than ordinary SFRC for the higher steel fiber volume ratio.


2021 ◽  
pp. 136943322110262
Author(s):  
Haiyan Zhang ◽  
Keyue Wan ◽  
Bo Wu ◽  
Zhonghao Hu

Geopolymer recycled aggregate concrete (GRAC) is a new green construction material, which uses geopolymer as the binder and recycled concrete as aggregates. To compare the flexural performance of GRAC and ordinary recycled aggregate concrete (RAC) beams, static loading tests were conducted on seven GRAC beams and three RAC beams. The effects of the replacement ratio of recycled aggregates (RAs), the replacement patterns, and the reinforcement ratio on the flexural behavior of GRAC beams are evaluated. The test data show that the replacement ratio has no significant effect on the cracking pattern, failure mode, or bending capacity of GRAC beams, but the replacement pattern does have an effect. Under a given replacement ratio, replacing only the larger fraction of natural aggregates (NA) with RA improves the concrete strength and crack resistance of both RAC and GRAC beams, compared to that using same replacement percentage for all fractions. Due to the lower elastic modulus and strength of GRAC prepared in this study, the GRAC beams have lower height of neutral axis and greater deflection than RAC beams at the same load level and possess slightly lower cracking load, bending capacity, and ductility. The bending capacity of GRAC beams can be predicted by the formulas proposed for ordinary reinforced concrete beams in the Chinese code GB50010-2010, ACI 318-11, or BS EN 1992-1-1:2004 codes, but the safety margin is generally lower than that of ordinary reinforced concrete beams.


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