Cyclic Stress-Strain Model for Air-Entrained Recycled Aggregate Concrete after Freezing-and-Thawing Cycles

2018 ◽  
Vol 115 (3) ◽  
Author(s):  
Kaihua Liu ◽  
Jiachuan Yan ◽  
Chaoying Zou ◽  
He Wu
Keyword(s):  
Cyclic Stress ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Freezing And Thawing ◽  
Stress Strain ◽  
Aggregate Concrete ◽  
Freezing And Thawing Cycles ◽  
Strain Model

Eccentric compressive behavior of recycled aggregate concrete columns after freezing and thawing cycles

2018 ◽  
Vol 21 (15) ◽  
pp. 2299-2310 ◽  
Author(s):  
Jiachuan Yan ◽  
Kaihua Liu ◽  
Chaoying Zou ◽  
Jian Wang
Keyword(s):  
Coarse Aggregate ◽  
Concrete Columns ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Compressive Behavior ◽  
Freezing And Thawing ◽  
Replacement Ratio ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Freezing And Thawing Cycles

The eccentric compressive behavior of 18 recycled aggregate concrete columns after freezing and thawing cycles were investigated. The effect of the number of freezing and thawing cycles, the replacement ratio of recycled coarse aggregate, and the eccentricity of axial loading on the eccentric compressive behavior of columns was analyzed. The results show that the strain distribution along the depth of cross section of columns was plane during the eccentric compression test after freezing and thawing cycles. With the increase in the freezing and thawing cycles and the replacement ratio of recycled coarse aggregate, the failure modes of partial specimens turned from ductile tension failure to brittle compression failure. Two existing design methods for calculating the bearing capacity of conventional concrete columns subjected to eccentric compressive loading were verified to be effective for evaluating that of recycled aggregate concrete columns after limited freezing and thawing cycles.

scholarly journals Axial Stress-Strain Performance of Recycled Aggregate Concrete Reinforced with Macro-Polypropylene Fibres

2021 ◽  
Vol 13 (10) ◽  
pp. 5741
Author(s):  
Muhammad Junaid Munir ◽  
Syed Minhaj Saleem Kazmi ◽  
Yu-Fei Wu ◽  
Xiaoshan Lin ◽  
Muhammad Riaz Ahmad
Keyword(s):  
Axial Stress ◽  
Peak Stress ◽  
Polypropylene Fibre ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Peak Strain ◽  
Stress Strain ◽  
Polypropylene Fibres ◽  
Aggregate Concrete

The addition of macro-polypropylene fibres improves the stress-strain performance of natural aggregate concrete (NAC). However, limited studies focus on the stress-strain performance of macro-polypropylene fibre-reinforced recycled aggregate concrete (RAC). Considering the variability of coarse recycled aggregates (CRA), more studies are needed to investigate the stress-strain performance of macro-polypropylene fibre-reinforced RAC. In this study, a new type of 48 mm long BarChip macro-polypropylene fibre with a continuously embossed surface texture is used to produce BarChip fibre-reinforced NAC (BFNAC) and RAC (BFRAC). The stress-strain performance of BFNAC and BFRAC is studied for varying dosages of BarChip fibres. Results show that the increase in energy dissipation capacity (i.e., area under the curve), peak stress, and peak strain of samples is observed with an increase in fibre dosage, indicating the positive effect of fibre addition on the stress-strain performance of concrete. The strength enhancement due to the addition of fibres is higher for BFRAC samples than BFNAC samples. The reduction in peak stress, ultimate strain, toughness and specific toughness of concrete samples due to the utilisation of CRA also reduces with the addition of fibres. Hence, the negative effect of CRA on the properties of concrete samples can be minimised by adding BarChip macro-polypropylene fibres. The applicability of the stress-strain model previously developed for macro-synthetic and steel fibre-reinforced NAC and RAC to BFNAC and BFRAC is also examined.

Compressive stress–strain behavior of steel fiber reinforced-recycled aggregate concrete

2014 ◽  
Vol 46 ◽  
pp. 65-72 ◽  
Author(s):  
Jodilson Amorim Carneiro ◽  
Paulo Roberto Lopes Lima ◽  
Mônica Batista Leite ◽  
Romildo Dias Toledo Filho
Keyword(s):  
Compressive Stress ◽  
Steel Fiber ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Aggregate Concrete ◽  
Strain Behavior

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.

scholarly journals A Study on the Properties of Recycled Aggregate Concrete and Its Production Facilities

2019 ◽  
Vol 9 (9) ◽  
pp. 1935 ◽  
Author(s):  
Jung-Ho Kim ◽  
Jong-Hyun Sung ◽  
Chan-Soo Jeon ◽  
Sae-Hyun Lee ◽  
Han-Soo Kim
Keyword(s):  
Drying Shrinkage ◽  
Quality Standards ◽  
Poor Quality ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Freezing And Thawing ◽  
Construction Waste ◽  
Aggregate Concrete ◽  
Air Volume

In recent years, the amount of construction waste and recycled aggregate has been increasing every year in Korea. However, as the recycled aggregate is poor quality, it is not used for concrete, and the Korean government has strengthened the quality standards for recycled aggregate for concrete. In this study, research was conducted on the mechanical and durability characteristics of concrete using recycled aggregate, after developing equipment to improve the quality of recycled aggregate to increase the use of recycled aggregate for environmental improvements. The results illustrated improvements in the air volume, slump, compressive strength, freezing and thawing resistance, and drying shrinkage. Furthermore, this study is expected to contribute to the increased use of recycled aggregate in the future.

scholarly journals Properties of Concrete Using Treated Low-Class Recycled Coarse Aggregate and Blast Furnace Slag Sand

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 843
Author(s):  
Yuji Miyazaki ◽  
Takeshi Watanabe ◽  
Yuji Yamada ◽  
Chikanori Hashimoto
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Hardened Concrete ◽  
Freezing And Thawing ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Furnace Slag

Since high quality natural aggregates are becoming scarce, it is important that industrial recycled products and by-products are used as aggregates for concrete. In Japan, the use of recycled aggregate (RG) is encouraged. Since, strength and durability of recycled aggregate concrete is lower than that of normal aggregate concrete, the use of recycled aggregate has not been significant. In order to improve physical properties of concrete using recycled coarse aggregate, blast furnace slag sand has been proposed. Recently, blast furnace slag sand is expected to improve durability, freezing, and thawing damage of concrete in Japan. Properties of fresh and hardened concrete bleeding, compressive strength, and resistance to freezing and thawing which are caused by the rapid freezing and thawing test using liquid nitrogen is a high loader than the JIS A 1148 A method that were investigated. As a result, concrete using treated low-class recycled coarse aggregate and 50% or 30% replacement of crushed sand with blast furnace slag sand showed the best results, in terms of bleeding, resistance to freezing and thawing.

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