The Study of Field Effect through Uniaxial Compression Experiment on Marine Recycled Concrete Specimen Based on DPDM Technique

2012 ◽  
Vol 446-449 ◽  
pp. 1735-1742
Author(s):  
Wen Bai Liu ◽  
Chao Shen ◽  
Xia Li ◽  
Hong Ming Jiang
Keyword(s):  
Uniaxial Compression ◽  
Field Effect ◽  
Strain Curve ◽  
Heterogeneous Material ◽  
Concrete Specimen ◽  
Middle Part ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Replacement Rate ◽  
Compression Resistance

Recycled concrete is a kind of composite heterogeneous material. Through the uniaxial compression experiment on recycled concrete specimen, the corresponding stress-strain curve is depicted with the major variables of replacement rate of recycled aggregate and time of corrosion by seawater, and the analysis of compression resistance capacity of recycled concrete sample is carried out by comparing common samples with those after the process of vacuum pumping. According to the results of comparison, the process of vacuum pumping can raise the strength of concrete by 9% to 22% and the lowering speed of compression resistance capacity rises as replacement rate of recycled aggregate goes up after the same corrosion period. The compression resistance capacity of the concrete specimen with replacement rate of 60% descends 50% to 80% faster than the sample with 30% of rate. DPDM technique is used to analyze deformation field, displacement field and strain field of concrete specimen during the process of uniaxial compression. As shown in the images from the experiment, the cracks develop from the bottom and both edges towards the middle part along the direction of loading until some of them run through the cube with the failure of the overall specimen while the stress reaches the peak, the displacement amount decreases from bottom to top and from both edges to center and the greatest strain concentration scatters around the bottom of the specimen while the strain of 62% appears around the peak stress of 33-36MPa. This paper puts forward constructive references and guidance for the application of recycled concrete in marine engineering on the basis of the study of field effect through uniaxial compression experiment based on DPDM technique.

Numerical Simulation of Marine Recycled Concrete Specimen Based on ABAQUS

2012 ◽  
Vol 482-484 ◽  
pp. 621-626
Author(s):  
Wen Bai Liu ◽  
Wang Nan Chen ◽  
Xia Li
Keyword(s):  
Numerical Simulation ◽  
Uniaxial Compression ◽  
Sea Water ◽  
Strain Curve ◽  
Concrete Specimen ◽  
Water Erosion ◽  
Recycled Concrete ◽  
Experimental Results ◽  
Stress Strain Curve ◽  
Stress Strain

Based on ABAQUS, this article builds up a dispersion cracking model and carries out the numerical simulation of the influence of sea water erosion depth and intension upon marine recycled concrete specimen. Compared with stress-strain curve from the experiment, it can be easily found that the experimental results match well with that of simulation through the numerical simulation of uniaxial compression on average concrete, recycled concrete corroded by seawater and the same concrete after vacuum pumping, which shows two kinds of curves stay close to each other. From the results of the simulation, strain develops from the edges to the middle of the cube until it runs through the whole section, which basically corresponds with the outcome observed in the experiment.

scholarly journals Discrete Element Simulation Analysis of Biaxial Mechanical Properties of Concrete with Large-Size Recycled Aggregate

2021 ◽  
Vol 13 (13) ◽  
pp. 7498
Author(s):  
Tan Li ◽  
Jianzhuang Xiao
Keyword(s):  
Mechanical Properties ◽  
Stress State ◽  
Strain Curve ◽  
Confining Pressure ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Model ◽  
Large Size

Concrete made with large-size recycled aggregates is a new kind of recycled concrete, where the size of the recycled aggregate used is 25–80 mm, which is generally three times that of conventional aggregate. Thus, its composition and mechanical properties are different from that of conventional recycled concrete and can be applied in large-volume structures. In this study, recycled aggregate generated in two stages with randomly distributed gravels and mortar was used to replace the conventional recycled aggregate model, to observe the internal stress state and cracking of the large-size recycled aggregate. This paper also investigated the mechanical properties, such as the compressive strength, crack morphology, and stress–strain curve, of concrete with large-size recycled aggregates under different confining pressures and recycled aggregate incorporation ratios. Through this research, it was found that when compared with conventional concrete, under the confining pressure, the strength of large-size recycled aggregate concrete did not decrease significantly at the same stress state, moreover, the stiffness was increased. Confining pressure has a significant influence on the strength of large-size recycled aggregate cocrete.

Study on the Mechanical Properties and Frost Resistance of Recycled Concrete Prepared by Village Construction Wastes

2011 ◽  
Vol 418-420 ◽  
pp. 406-410
Author(s):  
Jun Liu ◽  
Yao Li ◽  
Dan Dan Hong ◽  
Yu Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Frost Resistance ◽  
Cement Mortar ◽  
Strength Loss ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Replacement Rate ◽  
Concrete Mechanical Properties ◽  
Better Than

Abstract. Recycled aggregate—rural building material wastes pretreated by cement mortar—are applied into concrete with different replacement rates: 0, 25%, 50%, 75%, and 100%. Results from measurements of compressive strength, cleavage tensile strength, mass loss after fast freeze-thaw cycles, and compressive strength loss indicate that a different recycled aggregate replacement rate certainly influences concrete mechanical properties and frost resistance. Recycled aggregate replacement rates less than 75% performs better than common concrete. Data from the 100% replacement rate is worse than that of rates less than 75% but still satisfy the general demands of GB standard on C30 concrete.

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.

Experimental Study on Mechanical Properties of Recycled Concrete Specimens of Marine Engineering

2011 ◽  
Vol 71-78 ◽  
pp. 331-337
Author(s):  
Wen Bai Liu ◽  
Xia Li
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Engineering Application ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Replacement Rate ◽  
Replacement Ratio ◽  
Ordinary Concrete ◽  
Seawater Corrosion ◽  
Marine Engineering

Mechanical properties of recycled concrete under different conditions were studied in this paper. Based on three kinds of replacement percentage of recycled aggregate and four kinds of seawater corrosion conditions, the experimental study of mechanical properties of recycled concrete specimens corroded by seawater and produced under vacuum conditions were conducted, and compared with that of ordinary concrete specimens. Testing results show that compressive strength of recycled concrete decreases with the increase of both the replacement rate of recycled aggregate and the corrosion time by seawater, with the maximum reduce value is 17.96% and 24.52%; Vacuum conditions effectively improve the strength of recycled concrete, improved value is 1.03-1.19 times of the same replacement ratio of recycled aggregate, and 1.00-1.16 times of the ordinary concrete. It provides the reference for marine engineering application of recycled concrete.

scholarly journals Compressive Strength Study on the Freeze-thaw Resistance of Recycled Aggregate Concrete Members

2017 ◽  
Vol 11 (1) ◽  
pp. 270-280 ◽  
Author(s):  
Haicheng Niu ◽  
Yonggui Wang ◽  
Xianggang Zhang ◽  
Xiaojing Yin
Keyword(s):  
Compressive Strength ◽  
Mass Loss ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Replacement Rate ◽  
Aggregate Concrete ◽  
Freeze Thaw ◽  
Surface Scaling

Introduction: Freeze-thaw resistance of recycled aggregate concrete with partial or total replacement of recycled aggregate compared with that of natural aggregate concrete was investigated in this paper. Method: Ninety specimens were fabricated to study the influence of different recycled aggregate replacement ratios on the surface scaling, mass loss, and residual compressive strength after 100 freeze-thaw cycles. Results: The experiment results indicate that the type of recycled aggregate and its replacement ratio have significant effects on the freeze-thaw performance. The cubic compressive strength of recycled aggregate concrete is overall slightly lower than that of normal concrete. After 100 freeze-thaw cycles, the compressive strength decreases and the reduction extent increases with increasing replacement rate of recycled aggregate. The surface scaling of reinforced recycled concrete prisms tends to be more severe with the increase of freeze-thaw cycles. Conclusion: Furthermore, a notable rise in mass loss and the bearing capacity loss is also found as the substitution ratio increases. Under the same replacement rate, recycled fine aggregate causes more negative effects on the freeze-thaw resistance than recycled coarse aggregate.

Experimental Study on Flexural Property of Reinforced Concrete Beams with Recycled Aggregate of Construction Waste

2012 ◽  
Vol 517 ◽  
pp. 601-605
Author(s):  
Zhao Hua Du ◽  
Tong Hao ◽  
Li Xin Liu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Recycled Concrete ◽  
Reinforced Concrete Beams ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Flexural Property ◽  
Test Results ◽  
Replacement Rate ◽  
Construction Waste

This paper presents the test results of 6 reinforced concrete beams with recycled aggregates of construction waste under flexure, the beams were made of two strength grade concrete of and with different recycled aggregate replacement rate. The results indicate: the ultimate bearing capacity of recycled concrete beams with natural aggregate concrete beams are almost the same, and can meet the requirements of chinese code; The cracking resistance of the reinforced recycled concrete beams is slightly less than that of the beams with natural aggregates, the influence of recycled aggregate replacement rate to cracking resistance is not obvious. Recycled concrete beam crack load the calculated value is greater than the measured value, should carry out the theoretical value adjustment. Reinforced concrete beams is one of concrete structures, its the most common and most important component, Study of flexural property of reinforced concrete for recycled concrete structure component in the popularization and application to have the important significance [. This paper presents the test results of 6 reinforced concrete beams with recycled aggregates of construction waste under flexure, the beams were made of two strength grade concrete of C30 and C40 and with different recycled aggregate replacement rate of 0%, 50% and 70%. These results may be as a reference for the application of the concrete with recycled aggregates of construction waste in engineering [2,3,.

Microscopic Mechanism Study on Carbonation Resistance of Recycled Aggregate Concrete

2011 ◽  
Vol 194-196 ◽  
pp. 1001-1006 ◽  
Author(s):  
Hai Feng Yang ◽  
Zhi Heng Deng ◽  
Xue Liang Li
Keyword(s):  
Fly Ash ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Replacement Rate ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Concrete Carbonation ◽  
Carbonation Resistance

24 100mm × 100mm × 300mm recycled concrete prisms and 96 150mm × 150mm × 150mm cubes are completed in this paper.The relationships of the carbonation depth in each carbonation age with replacement rate of recycled coarse aggregate and fly ash is studied; The SEM is used to observe the interface structure of recycled coarse aggregate concrete and compared with ordinary concrete, and finally,a recycled concrete carbonation model is proposed. The results showed that: the substitution of recycled coarse aggregate and fly ash cut down the recycled concrete carbonation resistance significantly, which are related with the replacement rate; the content of Ca(OH)2 in the recycled aggregate concrete decreased ,also there are obvious interface transition zone between the recycled coarse aggregate and the new cement;obvious cracks and large voids are exist before the recycled aggregate concrete is loaded, which lead directly to lower carbonation resistance of the recycled concrete.

Study Strength of Recycled Concrete Mix Design

2013 ◽  
Vol 423-426 ◽  
pp. 1072-1075
Author(s):  
Xin Hua Zhang ◽  
Sai Tian ◽  
Huai Ru Dai ◽  
Wei Lin ◽  
Zhi Chun Yao ◽  
...  
Keyword(s):  
Concrete Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Mix Design ◽  
Replacement Rate ◽  
Ordinary Concrete ◽  
Concrete Mix Design ◽  
Waste Production ◽  
Concrete Mix

This paper discusses waste production of recycled aggregate concrete is used as the recycled concrete, experiment with different recycled aggregate instead of natural aggregate, the ratio of recycled concrete workability and compressive strength etc performance compared with ordinary concrete, analyzing the change of the recycled aggregate replacement rate on the influence of concrete strength.

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