Effects of rubbing action in manufacturing process of recycled coarse aggregate from waste concrete on strength and durability of recycled concrete products

Author(s):  
Y. Hosokawa
2011 ◽  
Vol 261-263 ◽  
pp. 19-23 ◽  
Author(s):  
Da Xing Qian ◽  
Ying Wei Yun ◽  
Ii Young Jang ◽  
Jong Hoe Kim

Recently reutilization of waste concrete becomes one of the hottest issues in civil engineering field throughout the world. However, most of the concerned research focuses on the RCA (recycled coarse aggregate) by simply crushing waste concrete. In this paper shucking technique is developed to secondary process the simply crushing waste concrete for improving the performance of RCA concrete. Test has been done to demonstrate that performances such as strength, elastic modulus et al. of shucking RCA concrete is better than those of common recycled concrete. Simultaneously, beam specimens are made to test the flexural behavior of shucking RCA concrete. Results showed that the deflection of shucking RCA concrete beam is approximately same with that of natural coarse aggregate concrete beam, which solves current problem that recycled aggregate concrete beam has bigger deflection than common concrete beam. The new shucking technique developed in this paper has many advantages to be applied in practical engineering and it has obvious economic benefits and social effect.


2011 ◽  
Vol 346 ◽  
pp. 47-51 ◽  
Author(s):  
M. Mandula ◽  
Xiao Yu Hu ◽  
Feng Jin Chen ◽  
Wen Long Zhang

This paper studies the recycling of solid waste concrete of the foundational content. Through the experimental research on the use of recycled aggregate and recycled concrete powder, I propose recycled coarse aggregate, recycled powder of various physical and chemical characteristic and the powder mixed with cement slurry mixed with recycled coarse aggregate on the surface of the mechanical properties after treatment. The results show that the coarse aggregate crushing value after surface treatment, strength characteristics of concrete can meet the requirements of ordinary concrete.


2012 ◽  
Vol 174-177 ◽  
pp. 275-279
Author(s):  
Da Xing Qian ◽  
Ying Wei Yun ◽  
Il Young Jang ◽  
Woo Young Park

In this paper shucking technique is developed to improve the performance of recycled coarse aggregate concrete. Comparison test has been done to demonstrate the good performance of shucking recycled coarse aggregate concrete than that of common recycled concrete. Simultaneously recycled fine aggregate concrete and recycled finely grinded admixture are extracted and studied too. Results show that this new technique can not only improve the performance of recycled material and enlarge recycled material type, but also make waste concrete to be reused completely.


2020 ◽  
Vol 12 (24) ◽  
pp. 10544
Author(s):  
Chunhong Chen ◽  
Ronggui Liu ◽  
Pinghua Zhu ◽  
Hui Liu ◽  
Xinjie Wang

Carbonation durability is an important subject for recycled coarse aggregate concrete (RAC) applied to structural concrete. Extensive studies were carried out on the carbonation resistance of RAC under general environmental conditions, but limited researches investigated carbonation resistance when exposed to chloride ion corrosion, which is an essential aspect for reinforced concrete materials to be adopted in real-world applications. This paper presents a study on the carbonation durability of two generations of 100% RAC with the effect of chloride ion corrosion. The quality evolution of recycled concrete coarse aggregate (RCA) with the increasing recycling cycles was analyzed, and carbonation depth, compressive strength and the porosity of RAC were measured before and after chloride ion corrosion. The results show that the effect of chloride ion corrosion negatively affected the carbonation resistance of RAC, and the negative effect was more severe with the increasing recycling cycles of RCA. Chloride ion corrosion led to a decrease in compressive strength, while an increase in carbonation depth and the porosity of RAC. The equation of concrete total porosity and carbonation depth was established, which could effectively judge the deterioration of carbonation resistance of RAC.


2011 ◽  
Vol 477 ◽  
pp. 280-289 ◽  
Author(s):  
Shao Wei Yao ◽  
Zhen Guo Gao ◽  
Chang Rui Wang

The properties of recycled coarse aggregate and the slump, the physical and mechanical properties and durability of recycled aggregate concrete were studied through tests. The results indicate that the slump, compressive strength and durability of concrete with recycled aggregate are lower than that of concrete with natural aggregate when recycled coarse aggregate fully absorbs water. However, the slump can be similar to that of concrete with natural aggregate. The properties of recycled aggregate concrete can be improved by strengthening the recycled coarse aggregate, and it is also found that the recycled coarse aggregate strengthened by grinding is superior to that soaked by chemical solution.


2021 ◽  
Vol 13 (23) ◽  
pp. 13200
Author(s):  
Yang Yu ◽  
Peihan Wang ◽  
Zexin Yu ◽  
Gongbing Yue ◽  
Liang Wang ◽  
...  

Shrinkage property is a significant indicator of the durability of concrete, and the shrinkage of green recycled concrete is particularly problematic. In this paper, construction waste was crushed and screened to generate simple-crushed recycled coarse aggregate (SCRCA). The SCRCA was then subjected to particle shaping to create primary particle-shaped recycled coarse aggregate (PPRCA). On this basis, the PPRCA was particle-shaped again to obtain the secondary particle-shaped recycled coarse aggregate (SPRCA). Under conditions where the dosage of cementitious material is 300 kg/m3 and the sand rate is 38%, a new high-belite sulphoaluminate cement (HBSAC) with low carbon emission and superior efficiency was used as the basic cementitious material. Taking the quality of recycled coarse aggregate (SCRCA, PPRCA, and SPRCA) and the replacement ratio (25%, 50%, 75%, and 100%) as the influencing factors to prepare the green recycled concrete, the workability and shrinkage property of the prepared concrete were analyzed. The results show that the water consumption of green recycled concrete decreases as the quality of the recycled coarse aggregate (RCA) increases and the replacement ratio decreases, provided that the green recycled concrete achieves the same workability. With the improvement of RCA quality and the decrease of replacement ratio, the shrinkage of recycled concrete decreases. The shrinkage performance of green recycled concrete configured with the SPRCA completely replacing the natural coarse aggregate (NCA) is basically the same as that of the natural aggregate concrete (NAC).


2018 ◽  
Vol 7 (3.35) ◽  
pp. 1
Author(s):  
T. V. Arul Prakash ◽  
Dr. M. Natarajan ◽  
Dr. T. Senthil Vadivel ◽  
K. Vivek

This article presents the influence of the Recycled Concrete Aggregate (RCA) on the mechanical properties of self-compacting fly ash concrete (M30 Grade). The RCA from local construction demolition site were employed as a replacement for natural coarse aggregate (0% - 30%) in self-compacting concrete (SCC). The Viscosity modifying material used in this study was Class F fly ash. The results indicate that recycled concrete aggregate can be replaced by an optimal 25% replacement percentage in the manufacture of SCC without significantly affecting strength and durability.  


2020 ◽  
Vol 7 ◽  
Author(s):  
Dingyi Xu ◽  
Zongping Chen ◽  
Chunheng Zhou

This study was conducted to experimentally investigate the behavior of recycled concrete-filled circular steel tube (RCFST) columns subjected to cyclic loading. Ten specimens were prepared and tested. Four parameters were used to characterize seismic behavior: the replacement percentage of recycled coarse aggregate, slenderness ratio, axial compression level, and steel ratio. A novel calculation method for the bearing capacity for RCFST columns is established. The failure processes and modes of RCFST columns are found to be similar to normal concrete-filled steel tube columns. Varying the replacement percentage of recycled coarse aggregate has little effect on the hysteresis curves of the RCFST columns. The RCFST columns also show seismic performance similar to that of concrete-filled steel tubes. The displacement ductility of all specimens is larger than 3.0 and the equivalent viscous damping coefficients corresponding to the ultimate load range from 0.305 to 0.460.


2012 ◽  
Vol 166-169 ◽  
pp. 1614-1619 ◽  
Author(s):  
Wen Yue Qin ◽  
Yu Liang Chen ◽  
Zong Ping Chen

In order to reveal the flexural behavior of normal section of steel reinforced recycled coarse aggregate concrete beams,6 steel reinforced recycled concrete beams were designed for flexural test,the study mainly considered the impact of coarse aggregate replacement rates and concrete strength grade two changing parameters on the flexural behavior of steel reinforced recycled coarse aggregate concrete beams. Through this test, the whole mechanical process、crack distribution and failure behavior of this kind of specimens were observed, and obtained the stress-strain distribution curves、the ultimate bearing capacity and load-displacement curves parameters. Based on the study measurement data, deeply analyzed the impact of coarse aggregate replacement rates and concrete strength grade on the flexural behavior of steel reinforced recycled coarse aggregate concrete beams. The result shows that: steel reinforced recycled coarse aggregate concrete beams’ failure pattern was similar to normal SRC beams, during loading process the section strain agreed with the plane-section assumption, and the beams have good bearing capacity and deformation performance.


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