scholarly journals Study on the Effect of Recycled Coarse Aggregate on the Shrinkage Performance of Green Recycled Concrete

2021 ◽  
Vol 13 (23) ◽  
pp. 13200
Author(s):  
Yang Yu ◽  
Peihan Wang ◽  
Zexin Yu ◽  
Gongbing Yue ◽  
Liang Wang ◽  
...  
Keyword(s):  
Primary Particle ◽  
Coarse Aggregate ◽  
Cementitious Material ◽  
Recycled Concrete ◽  
Low Carbon ◽  
Replacement Ratio ◽  
Recycled Coarse Aggregate ◽  
Shrinkage Property ◽  
Low Carbon Emission

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).

Study on Affection of the PVA Fiber on Recycled Coarse Aggregate to Porous Concrete Performance

2013 ◽  
Vol 438-439 ◽  
pp. 304-308 ◽  
Author(s):  
Du La Man
Keyword(s):  
Coarse Aggregate ◽  
Effective Porosity ◽  
Replacement Ratio ◽  
Porous Concrete ◽  
Recycled Coarse Aggregate ◽  
Contraction Property ◽  
Dry Shrinkage ◽  
Pva Fiber ◽  
Shrinkage Property ◽  
Skeleton Structure

Pervious concrete is one kind of porous concrete which has skeleton structure. In this test the recycled coarse aggregate replacement ratio is 30%, by using recycled coarse aggregate which through high quality processing replaces ordinary coarse aggregate and adding PVA fiber (the mass of PVA fiber respectively are 0%, 0.5%, 1.0% and 1.5% of the cement), the influences of PVA fiber on the strength, effective porosity and permeable coefficient of porous concrete are studied. Besides, the dry shrinkage property and temperature contraction property of porous concrete are discussed. The results can provide the basis for the design and application of the recycled coarse aggregate porous concrete.

Experimental Study on Mix Proportion and Fundamental Properties of Recycled Concrete

2012 ◽  
Vol 598 ◽  
pp. 635-639
Author(s):  
Zhao Hua Du ◽  
Jie Wang
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Replacement Ratio ◽  
Mixture Ratio ◽  
Recycled Coarse Aggregate ◽  
Fundamental Properties ◽  
Mix Proportion ◽  
Strength Tests

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.

Experimental Study on Compressive Strength of Recycled Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 75-78 ◽  
Author(s):  
Yi Li ◽  
Jun Lin Tao ◽  
Ting Lei ◽  
Jian Jun Xie
Keyword(s):  
Growth Rate ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Testing Machine ◽  
Recycled Concrete ◽  
Concrete Compressive Strength ◽  
Replacement Ratio ◽  
Recycled Coarse Aggregate ◽  
Study Results ◽  
Compressive Strength Test

Recycled concrete which are made by waste concrete has significance of environmental protection and saving natural resources. But there are different study results of recycled concrete of domestic and foreign scholars, so it is necessary to do the further study of recycled concrete. Compressive strength test of 225 concrete standard cube specimens have been done by Hydraulic Type Universal Testing Machine, and the relationships among recycled concrete compressive strength, age and recycled coarse aggregate replacement ratio have been studied. The results show: the growth rate of early strength of recycled concrete is smaller than natural concrete of the same gradation and the growth rate of later strength of recycled concrete is faster than natural concrete; when the recycled coarse aggregate replacement ratio increases the compressive strength of concrete decreases, and when the recycled coarse aggregate replacement ratio is over 70%, the decrease ranges more apparent.

Study on Strength Estimating of Recycled Concrete Based on Rebound Method and Ultrasonic-Rebound Combined Method

2011 ◽  
Vol 243-249 ◽  
pp. 5470-5474 ◽  
Author(s):  
Jun Chen ◽  
You Wen Su ◽  
Ting Lei ◽  
Song Gu
Keyword(s):  
Experimental Verification ◽  
Coarse Aggregate ◽  
Large Error ◽  
Recycled Concrete ◽  
Combined Method ◽  
Replacement Ratio ◽  
Recycled Coarse Aggregate ◽  
Test Conditions

In order to test the applicability of the strength curves of rebound method and ultrasonic-rebound combined method of common concrete in estimating the strength of recycled concrete, basis on the C30 recycled concrete specimens with 70% of recycled coarse aggregate replacement are designed, then changing the replacement ratio of recycled coarse aggregate for experimental verification. The results show that It will lead to a large error if using the strength curves of common concrete to estimate the strength of recycled concrete, and the error grows with the growth of the replacement ratio of recycled coarse aggregate. So It is necessary to establish the special purpose strength curves of recycled concrete with the rate of recycled coarse aggregate. Finally, the strength curves of recycled concrete with recycled coarse aggregate are 30%,50%,70% and 100% are given in this test conditions in this paper.

Experimental study on flexural property of self-compacting concrete beams with discontinuous graded recycled coarse aggregate

2020 ◽  
pp. 10-15
Author(s):  
Wu Chunyang ◽  
FU Jiajia ◽  
Wang Yao
Keyword(s):  
Experimental Study ◽  
Failure Modes ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Flexural Property ◽  
Replacement Ratio ◽  
Flexural Members ◽  
Recycled Coarse Aggregate ◽  
Current Design

Experimental study on the flexural property of self-compacting recycled concrete (SCRC) beams with discontinuous graded recycled coarse aggregate is carried out with different replacement ratio of recycled aggregate and concrete grade. The similarities and differences on the failure modes between 4 SCRC beams and 2 normal beams were discussed. According to various replacement ratio of recycled aggregate and concrete grade，the influence on the carrying capacity，cracking ability，etc. of SCRC beams with discontinuous graded recycled coarse aggregate was also analysed. The results show that the failure modes, cracks of pure bend of SCRC beams and normal ones are similar. The vertical crack width of SCRC beams are bigger than the normal beams. There are small cracks in the shear bending section. The ultimate strength decrease slightly and the calculation formulas of current design standard can be used of flexural members which are made of SCRC.

scholarly journals Carbonization Durability of Two Generations of Recycled Coarse Aggregate Concrete with Effect of Chloride Ion Corrosion

2020 ◽  
Vol 12 (24) ◽  
pp. 10544
Author(s):  
Chunhong Chen ◽  
Ronggui Liu ◽  
Pinghua Zhu ◽  
Hui Liu ◽  
Xinjie Wang
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Chloride Ion ◽  
Total Porosity ◽  
Recycled Concrete ◽  
Carbonation Depth ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Carbonation Resistance ◽  
Two Generations

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.

scholarly journals Seismic Performance of Recycled Concrete Filled Circular Steel Tube Columns

2020 ◽  
Vol 7 ◽  
Author(s):  
Dingyi Xu ◽  
Zongping Chen ◽  
Chunheng Zhou
Keyword(s):  
Seismic Performance ◽  
Coarse Aggregate ◽  
Slenderness Ratio ◽  
Steel Tube ◽  
Recycled Concrete ◽  
Load Range ◽  
Equivalent Viscous Damping ◽  
Displacement Ductility ◽  
Recycled Coarse Aggregate ◽  
Circular Steel Tube

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.

Experimental Study on Flexural Behaviors of Steel Reinforced Recycled Coarse Aggregate Concrete Beams

2012 ◽  
Vol 166-169 ◽  
pp. 1614-1619 ◽  
Author(s):  
Wen Yue Qin ◽  
Yu Liang Chen ◽  
Zong Ping Chen
Keyword(s):  
Bearing Capacity ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Recycled Concrete ◽  
Flexural Behavior ◽  
Aggregate Concrete ◽  
Strength Grade ◽  
Recycled Coarse Aggregate ◽  
The Impact

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.

Experimental Research on Mechanical Properties of Recycled Aggregate Concrete under Uniaxial Loading

2013 ◽  
Vol 671-674 ◽  
pp. 1736-1740
Author(s):  
Xue Yong Zhao ◽  
Mei Ling Duan
Keyword(s):  
Elastic Modulus ◽  
Coarse Aggregate ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Peak Strain ◽  
Stress Strain ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate

The complete stress-strain curves of recycled aggregate concrete with different recycled coarse aggregate replacement percentages were tested and investigated. An analysis was made of the influence of varying recycled coarse aggregate contents on the complete stress-strain curve, peak stress, peak strain and elastic modulus etc. The elastic modulus of RC is lower than natural concrete (NC), and with the recycled coarse aggregate contents increase, it reduces. While with the increase of water-cement ratio (W/C), recycled concrete compressive strength and elastic modulus improve significantly. In addition, put forward a new equation on the relationship between Ec and fcu of the RC.

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