Study on Recycled Aggregate Concrete Frame Joints with Method of Nonlinear Finite Element

2009 ◽  
Vol 417-418 ◽  
pp. 745-748
Author(s):  
Jian Zhuang Xiao ◽  
M.M. Tawana ◽  
Xiao Hui Zhu

With the achievements made in the research of mechanical properties for recycled aggregate concrete, this paper adopts the method of nonlinear finite element to analyze the seismic behavior of frame joints. The frame joints are made of recycled aggregate concrete. It also takes into account the bond behavior between steel bars and recycled aggregate concrete in the core area of the joints, and the force-displacement curve of the joints is calculated. Nonlinear finite element analysis shows that the results of the calculations are in accordance with the test results. It is concluded in this paper that, built models with nonlinear finite element method can be applied in simulating exactly the same seismic behavior of frame joints under low frequency reversed lateral loading.

2013 ◽  
Vol 357-360 ◽  
pp. 1383-1388 ◽  
Author(s):  
Hai Feng Yang ◽  
Zhi Heng Deng ◽  
Yue Feng Hu

In order to study the mechanistic differences between recycled aggregate concrete (RAC)and normal aggregate concrete(NAC), the magnifier and scanning electron microscope were used to observe the meso-interfacial structure and microstructure of interfacial transition zone morphology of the RAC respectively, and analysed differences between RAC and NAC; Secondly, the finite element software ABAQUS was used to simulation the simplified model of RAC. The above analysis results show that, there existe a transition zone in the interface, the aggregate-new mortar interface as well as the new-old mortar interface has been obvious cracks before loading, this part is the weak link of RAC ;After loading, the crack occurs first in the old interface, then appeared at the new interface, and then develop to the old mortar, finally, there formed a through crack.


2014 ◽  
Vol 1079-1080 ◽  
pp. 220-225
Author(s):  
Jia Li Fu ◽  
Bing Kang Liu ◽  
Jun Wei Ma ◽  
Hui Zhou

The torsional capacity oftwo recycled aggregate concrete (RAC) beams with 100% recycled coarse aggregate(RCA) and two normal concrete beams subjected to monotonic torsion was investigatedby the finite element software ABAQUS, and the simulated results were comparedwith the experimental results. The investigation shows that recycled aggregateconcrete torsional members have good seismic behavior. The simulated resultsagree well with experimental ones. It can be reference for actual engineering.


2013 ◽  
Vol 446-447 ◽  
pp. 1472-1476
Author(s):  
Xu Xiang Wang ◽  
Feng Liu ◽  
Wen Xian Feng ◽  
Lan Zeng

Horizontal bearing capacity and seismic resistance of Recycled aggregate Concrete Filled Steel Tube (RCFST) columns under low cyclic loads have been analyzed by nonlinear finite element software in this paper. A three-dimensional nonlinear finite element (FE) model was developed, and some parameters that affect the restoring force model of RCFST columns were studied, including axial compression ratio, steel ratio, steel yield strength, strength of core recycled aggregate concrete and recycled aggregate substitution rate. Analysis results show that, along with steel ratio, steel yield strength and recycled aggregate substitution rate increasing, seismic resistance of RCFST becomes better. However, the increase of core recycled aggregate concrete and axial compression ratio will weaken seismic resistance of RCFST columns.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2312
Author(s):  
Xin Liang ◽  
Fang Yan ◽  
Yuliang Chen ◽  
Huiqin Wu ◽  
Peihuan Ye ◽  
...  

In order to study the mechanical properties of recycled aggregate concrete (RAC) at different ages, 264 standard cubes were designed to test its direct shear strength and cube compressive strength while considering the parameters of age and recycled aggregate replacement ratio. The failure pattern and load–displacement curve of specimens at direct shearing were obtained; the direct shear strength and residual shear strength were extracted from the load–displacement curves. Experimental results indicate that the influence of the replacement ratio for the front and side cracks of RAC is insignificant, with the former being straight and the latter relatively convoluted. At the age of three days, the damaged interface between aggregate and mortar is almost completely responsible for concrete failure; in addition to the damage of coarse aggregates, aggregate failure is also an important factor in concrete failure at other ages. The load–displacement curve of RAC at direct shearing can be divided into elasticity, elastoplasticity, plasticity, and stabilization stages. The brittleness of concrete decreases with its age, which is reflected in the gradual shortening of the elastoplastic stage. At 28 days of age, the peak direct shear force increases with the replacement ratio, while the trend is opposite at ages of 3 days, 7 days, and 14 days, respectively. The residual strength of RAC decreases inversely to the replacement ratio, with the rate of decline growing over time. A two-parameter RAC direct shear strength calculation formula was established based on the analysis of age and replacement rate to peak shear force of RAC. The relationship between cube compressive strength and direct shear strength of recycled concrete at various ages was investigated.


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