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

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.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.671-674.1736 ◽

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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Experimental and Theoretical Investigation on the Thermo-Mechanical Properties of Recycled Aggregate Concrete Containing Recycled Rubber

Frontiers in Materials ◽

10.3389/fmats.2021.655097 ◽

2021 ◽

Vol 8 ◽

Author(s):

Yunchao Tang ◽

Wanhui Feng ◽

Zheng Chen ◽

Yumei Nong ◽

Minhui Yao ◽

...

Keyword(s):

Mechanical Properties ◽

Elevated Temperatures ◽

Microstructural Analysis ◽

Strain Curve ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Stress Strain ◽

Aggregate Concrete ◽

Recycled Rubber

The utilization of recycled aggregates made from construction wastes and recycled rubber made from waste tires is an effective method to realize the sustainable development. Thus, this study aims to determine the feasibility of using recycled aggregate concrete containing rubber, named rubberized recycled aggregate concrete (RRAC) as a new type of green-building material. The experimental carbon emissions test verified RRAC as a low-carbon material. In addition, the residual mechanical properties of RRAC were investigated under elevated temperatures. After exposure at 200, 400, and 600 C for 60 min, the stress−strain curve, compressive strength, energy absorption capacity, and spalling resistance of RRAC with recycled aggregate replacement ratios of 50 and 100%, rubber contents of 0, 5, 10, and 15% were explored with microstructural analysis. Moreover, empirical models were proposed to describe the effects of heated temperatures and rubber contents on the stress–strain relationship of RRAC. The results indicated that the rubber particles could reduce the spalling of specimens based on the vapor pressure theory. Therefore, this study provided scientific guidance for the design of structures made with RRAC for resisting high temperatures.

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Axial stress-strain behavior of macro-synthetic fiber reinforced recycled aggregate concrete

Cement and Concrete Composites ◽

10.1016/j.cemconcomp.2019.01.005 ◽

2019 ◽

Vol 97 ◽

pp. 341-356 ◽

Cited By ~ 28

Author(s):

Syed Minhaj Saleem Kazmi ◽

Muhammad Junaid Munir ◽

Yu-Fei Wu ◽

Indubhushan Patnaikuni ◽

Yingwu Zhou ◽

...

Keyword(s):

Axial Stress ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Synthetic Fiber ◽

Fiber Reinforced ◽

Stress Strain ◽

Aggregate Concrete ◽

Strain Behavior

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Stress–Strain Curve and Carbonation Resistance of Recycled Aggregate Concrete after Using Different RCA Treatment Techniques

Applied Sciences ◽

10.3390/app11094283 ◽

2021 ◽

Vol 11 (9) ◽

pp. 4283

Author(s):

Long Li ◽

Dongxing Xuan ◽

Chisun Poon

Keyword(s):

Elastic Modulus ◽

Strain Curve ◽

Peak Stress ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Stress Strain Curve ◽

Stress Strain ◽

Aggregate Concrete ◽

Treatment Techniques ◽

Carbonation Resistance

Five recycled coarse aggregate (RCA) treatment techniques including flow-through carbonation, pressurized carbonation, wet carbonation, nano silica (NS) pre-spraying and combined pressurized carbonation with NS pre-spraying, were utilized to improve the performance of recycled aggregate concrete (RAC). The characteristics of the stress–strain curves of RACs including peak stress, peak strain, elastic modulus, ultimate strain and toughness were evaluated after using the above RCA treatment techniques. A theoretical model for natural aggregate concrete was used to analyse the stress–strain curve of RAC. Additionally, the carbonation resistance of RAC after using different RCA treatment techniques were investigated. The results showed that the calculated stress–strain curve of RAC based on the theoretical model matched well with the experimental results. Among the three types of carbonation techniques, pressurized carbonation caused the highest improvement in peak stress and elastic modulus of RAC, followed by flow-through carbonation, the last was wet carbonation. The NS pre-spraying method contributed to even higher improvement in peak stress and elastic modulus of RAC than the pressurized carbonation method. The combined pressurized carbonation with NS pre-spraying exhibited the highest enhancement of RAC because both the RCA and the new interface transition zone (ITZ) were improved. The carbonation resistance of RAC was improved after using all the studied RCA treatment techniques.

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Axial stress–strain behavior of carbon FRP-confined seawater sea-sand recycled aggregate concrete square columns with different corner radii

Composite Structures ◽

10.1016/j.compstruct.2021.113589 ◽

2021 ◽

Vol 262 ◽

pp. 113589

Author(s):

Pengda Li ◽

Tianqi Yang ◽

Qiang Zeng ◽

Feng Xing ◽

Yingwu Zhou

Keyword(s):

Axial Stress ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Stress Strain ◽

Aggregate Concrete ◽

Strain Behavior ◽

Sea Sand

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Compressive Mechanical Properties of a Novel Recycled Aggregate Concrete with Recycled Lightweight Aggregate

Advances in Materials Science and Engineering ◽

10.1155/2021/2134082 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Anjun Li ◽

Gaoqiang Zhou ◽

Xianggang Zhang ◽

Ercong Meng

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Lightweight Aggregate ◽

Ultimate Strain ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Peak Strain ◽

Replacement Ratio ◽

Stress Strain ◽

Aggregate Concrete

A novel recycled aggregate concrete was prepared by replacing the natural aggregate with recycled lightweight aggregate. Subsequently, the mechanical properties and compressive stress-strain constitutive relation of the recycled lightweight aggregate concrete (RLWAC) were explored. For this purpose, the recycled lightweight aggregate (RLWA) replacement ratio (0%, 25%, 50%, 75%, and 100%) was selected as a variable, and the compressive strength of 15 cube and 30 prism specimens was evaluated. The failure morphology of the specimen was subsequently characterized, along with the cubic compressive strength, axial compressive strength, peak strain, ultimate strain, and other performance indices. The influence of the replacement ratio for the specimen indices of the RLWAC was also analyzed. It was observed that the dry apparent density of RLWAC decreased gradually on increasing the replacement ratio. Compared with 0% replacement ratio, a decrease of 6.50%, 11.39%, 21.84%, and 27.54% was observed, respectively. On enhancing the RLWA replacement ratio, the compressive strength, peak strain, and ultimate strain of RLWAC were observed to be gradually reduced. As the replacement ratio was increased from 75% to 100%, the peak strain was noted to decrease the most by about 6.8%. As the replacement ratio was increased from 50% to 75%, the ultimate strain decreased the most by about 14.2%. Based on the experimental findings, the functional relationships of the strength indices and the conversion value of each strength index with the replacement ratio were also established. Finally, based on the model proposed by the existing model, the stress-strain equation of RLWAC was developed, and the fitting results were observed to be in good agreement with the test results.

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Water-glass Module on Mechanical Properties of Geopolymer Recycled Aggregate Concrete

Journal of Physics Conference Series ◽

10.1088/1742-6596/2148/1/012060 ◽

2022 ◽

Vol 2148 (1) ◽

pp. 012060

Author(s):

Zhaoyang Ding ◽

Qun Su ◽

Hongguan Bian ◽

Qing Wang ◽

Jinghai Zhou

Keyword(s):

Mechanical Properties ◽

Water Glass ◽

Elasticity Modulus ◽

Peak Stress ◽

Hydration Product ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

National Standard ◽

Peak Strain ◽

Aggregate Concrete

Abstract Geopolymer recycled aggregate concrete (GRAC) was prepared by replacing cement with geopolymer and natural aggregate with wast concrete. The effect of water-glass modules on mechanical properties of GRAC was studied. It was found that there are tow kind of binding structures in geopolymer hydration product: C-A-S-H and N-A-S-H, they both contribute to the strength of GRAC. The value of size conversion coefficient of current national standard is inapplicable for GRAC, the calculation method of which is given in this paper. Elasticity modulus and peak stress of GRAC is proportional to water-glass modulus, and peak strain is inversely proportional and its constitutive equation was established.

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Effects of Different Strain Rates on the Impact Properties of Recycled Aggregate Concrete Modified With Nanosilica Solution and Polyvinyl Alcohol Fiber

Frontiers in Materials ◽

10.3389/fmats.2021.662374 ◽

2021 ◽

Vol 8 ◽

Author(s):

Xingguo Wang ◽

Maolin Jiang ◽

Xianggang Zhang ◽

Zhaoxia Cheng ◽

Jian Gong ◽

...

Keyword(s):

Polyvinyl Alcohol ◽

Strain Rate ◽

Peak Stress ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Peak Strain ◽

Aggregate Concrete ◽

Impact Properties ◽

Pva Fiber ◽

The Impact

The recycled aggregate (RA) was modified by 2% nanosilica solution, and the split Hopkinson pressure bar (SHPB) test device was used to study the dynamic impact properties of the modified recycled aggregate concrete (RAC) mixed with polyvinyl alcohol (PVA) fibers. The RA replacement percentage, the amount of PVA fiber, and the strain rate were variables. The failure pattern, the stress–strain curve of the nanosilica solution, and PVA fiber-modified RAC were shown under different strain rate conditions. Dynamic peak stress, peak strain, and dynamic increase factor (DIF) of the specimens are discussed. The results showed that the stress and dynamic peak strain value of the specimen increased with the increase of the strain rate; moreover, with the increase of the RA replacement percentage and the PVA fiber content, the dynamic peak stress of the specimen decreases, while the dynamic peak strain and the DIF value increase. The incorporation of nanosilica-modified RA is beneficial to the improvement of the impact performance of RAC, and the incorporation of an appropriate amount of the PVA fiber effectively improves the deformability of RAC.

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Compressive Behavior, Microstructural Properties, and Freeze–Thaw Behavior of Tailing Recycled Aggregate Concrete with Waste Polypropylene Fiber Addition

Materials ◽

10.3390/ma14216712 ◽

2021 ◽

Vol 14 (21) ◽

pp. 6712

Author(s):

Fan Xu ◽

Tao Li ◽

Chenghua Li ◽

Zhijun Li ◽

Sheliang Wang ◽

...

Keyword(s):

Polypropylene Fiber ◽

Strain Curve ◽

Peak Stress ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Cement Matrix ◽

Peak Strain ◽

Aggregate Concrete ◽

Freeze Thaw ◽

Thaw Cycle

To improve the high brittleness of recycled aggregate concrete containing iron ore tailings (TRAC), the feasibility of adding polypropylene fiber (PPF) to TRAC was studied by performing a compression stress–strain curve test, scanning electron microscope characterization, and a freeze–thaw cycle test. The results indicated that PPF had a beneficial impact on reducing the brittleness of TRAC. With the increase in PPF content, the peak strain increased, the elastic modulus decreased, and the peak stress and energy absorption capacity increased at first and then decreased. Furthermore, the microstructure investigation revealed that the interface friction between the PPF, aggregate, and cement matrix was the main source of energy dissipation. When the load acted on the concrete, the stress was dispersed to the fiber monofilaments, thus effectively enhancing the peak stress and peak strain of concrete and suppressing the generation and development of cracks in the concrete. In terms of freeze–thaw resistance, adding a small amount of PPF could reduce the negative effects of the freeze–thaw process on the cement matrix. On the premise of ensuring strength, the waste utilization should be as high as possible. Therefore, it was suggested that the content of PPF in fiber-reinforced tailings recycled aggregate concrete (TRAC-PP) should be 0.6%.

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