Static and Dynamic Behaviors of Fibre Reinforced Recycled Aggregate Mortar

2021 ◽  
Vol 882 ◽  
pp. 237-246
Author(s):  
Sallehan Ismail ◽  
Mohamad Asri Abd Hamid ◽  
Zaiton Yaacob
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Impact Load ◽  
Dynamic Compression ◽  
Recycled Aggregate ◽  
Fibre Reinforcement ◽  
Hopkinson Pressure Bar ◽  
Loading Test ◽  
Dynamic Increase Factor ◽  
Hybrid Fibre ◽  
The Impact

This study aims to explore the inclusion of microfibre in fine recycled aggregate (FRA) mortars under dynamic impact load. A 12-mm-diameter Split Hopkinson Pressure Bar (SHPB) was employed to test the impact of a recycled mortar with a single and hybrid fibre system and to determine potential improvements in its dynamic mechanical properties. In recycled mortar production, two microfibres with different sizes and types, namely, polypropylene and nylon, were added whilst keeping the amount of microfibres at a volumetrical fraction of 0.6%. An impact loading test was conducted by using the striking bar of SHPB at impact speeds of 2, 4 and 6 m/s. The effects of fibre on failure mode, tensile curve, compressive strength and dynamic increase factor (DIF) were then analysed. Experimental findings show that the improved mortar fibre mix has superior quasi-static and dynamic compression power compared with the reference mortar mix. Meanwhile, compared with the single fibre mix, the hybrid fibre mix is more effective in enhancing the dynamic compressive ability of the recycled mortar. The recycled-hybrid-fibre-enhanced mortar showed lower DIF values compared with the reference mortar, and the inclusion of fibre reinforcement can reduce the fragmentation of the recycled mortar mix after being subjected to impact.

scholarly journals Impact Properties of Recycled Aggregate Concrete with Nanosilica Modification

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xingguo Wang ◽  
Fei Cheng ◽  
Yixin Wang ◽  
Xianggang Zhang ◽  
Haicheng Niu
Keyword(s):  
Mechanical Properties ◽  
Split Hopkinson Pressure Bar ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Peak Strain ◽  
Hopkinson Pressure Bar ◽  
Aggregate Concrete ◽  
Dynamic Increase Factor ◽  
The Impact

The optimal soaking time and nanosilica concentration were chosen by the physical properties of the nanosilica-modified recycled aggregate. Recycled aggregate concrete (RAC) and nanosilica recycled aggregate concrete (SRAC) were fabricated by using ordinary recycled aggregate and nanosilica-modified recycled aggregate. Based on the comparative experimental study of basic mechanical properties, the effects of nanosilica recycled aggregate(SRA) modification and recycled aggregate(RA) replacement percentage on the basic mechanical properties of recycled concrete were analyzed. Finally, the split-Hopkinson pressure bar (SHPB) was used to conduct comparative experimental research on the impact resistance of recycled aggregate concrete and nanosilica-modified recycled aggregate concrete. The effects of nanosilica recycled aggregate modification and aggregate replacement percentage on failure morphology, dynamic peak stress, dynamic increase factor (DIF), dynamic peak strain were analyzed.

scholarly journals Study on Strain Rate Effect and Size Effect of Dynamic Response Characteristics of Granite

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Zhihang Hu ◽  
Yuying Ning ◽  
Jiuyang Zhang ◽  
Jianyu Zhao
Keyword(s):  
Aspect Ratio ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Impact Load ◽  
Hopkinson Pressure Bar ◽  
Aspect Ratios ◽  
Rate Of Increase ◽  
Density Index ◽  
The Impact ◽  
Time Density

Under impact load, the dynamic mechanical properties of rock are complex and changeable. The Split Hopkinson Pressure Bar (SHPB) system was used to change the impact load to carry out different strain rate loading tests on granite with different aspect ratios, and to analyze the influence of strain rate and aspect ratio on the dynamic energy consumption of granite crushing. The results show that at an impact velocity of 14 m/s, the granite with an aspect ratio of 1.4 appears to be strip-shaped fragments after being broken; the granite with an aspect ratio of 1.0 uniform square fragments after being broken; the granite with an aspect ratio of 0.6 appears to be a large number of flat fragments after being broken. When the load strain rate of the granite with an aspect ratio of 0.6 increases from 50 s-1 to 150 s-1, the energy-time density index increases significantly; when the load strain rate exceeds 150 s-1, the energy-time density index decreases. When the strain rate of granite with an aspect ratio of 1.0 exceeds 80 s-1, the energy-time density increases significantly. When the strain rate of the granite with an aspect ratio of 1.4 exceeds 60 s-1, the rate of increase of the energy-time density of the rock increases significantly.

scholarly journals Blasting Impact Simulation Test and Fragmentation Distribution Characteristics in an Open-Pit Mine

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaohua Ding ◽  
Xiang Lu ◽  
Wei Zhou ◽  
Xuyang Shi ◽  
Boyu Luan ◽  
...  
Keyword(s):  
Coal Mine ◽  
Wave Attenuation ◽  
Split Hopkinson Pressure Bar ◽  
Impact Load ◽  
Large Diameter ◽  
Test System ◽  
Open Pit ◽  
Hopkinson Pressure Bar ◽  
The Impact ◽  
The Relationship

Based on the split Hopkinson pressure bar (SHPB) test system, dynamic impact tests of coal specimens under different impact pressures were carried out to study the relationship between the impact load and the size of crushed lump coal. Based on the theory of stress wave attenuation, the relationship between the blasting impact load in a single-hole blasting area of a coal seam and the load applied in an impact failure test of a coal specimen in the laboratory was established. According to the characteristics of the fragmentation distribution of the coal specimens destroyed under a laboratory impact load and the requirement of the minimum cost control of coal blasting in an open-pit coal mine, the fragmentation size range was divided into three groups: large-diameter, medium-diameter, and powder particles. Based on this range, the variation rule of the mass percentage of coal fragments with impact pressure was obtained. Established on the evaluation principle of the blasting effect in an open-pit coal mine, a good impact fragmentation effect was obtained. The good pressure range is 0.30 MPa≤P<0.90 MPa.

scholarly journals Dynamic Compressive and Tensile Characteristics of a New Type of Ultra-High-Molecular Weight Polyethylene (UHMWPE) and Polyvinyl Alcohol (PVA) Fibers Reinforced Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Bashir H. Osman ◽  
Xiao Sun ◽  
Zhenghong Tian ◽  
Hao Lu ◽  
Guilin Jiang
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Construction Projects ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Dynamic Mechanical Properties ◽  
Hopkinson Pressure Bar ◽  
Dynamic Increase Factor ◽  
Fiber Concrete ◽  
New Type

The dynamic mechanical properties of concrete materials are important parameters for evaluating the safety performance of concrete structures under dynamic loads. Fiber cement-based materials have been widely used in the construction projects due to their strength, toughening, and cracking resistance. In this study, we conducted experimental and theoretical studies on dynamic compression and tensile mechanical properties of different proportions of new-type fiber concrete. A Split-Hopkinson pressure bar equipment was used to determine the concrete behavior at different strain rates. The effects of strain rate and fiber content on the strength of the specimen, dynamic increase factor, and ultimate strain were analyzed. Based on the macrodamage factor, the traditional nonlinear viscoelastic constitutive model was simplified and improved. The four-parameter constitutive model was obtained, and the influence of these parameters on the performance of fiber concrete was analyzed. The experimental results were compared with those predicted from the available equations, and results were in accordance. Finally, an analytical equation for predicting the dynamic compression and tensile properties of these new-type fibers was proposed.

SHPB Dynamic Experiment on Silica Fume Concrete

2013 ◽  
Vol 631-632 ◽  
pp. 771-775 ◽  
Author(s):  
Rong Jun Chen ◽  
Hong Wei Liu ◽  
Rui Zeng
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Silica Fume ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Impact Resistance ◽  
Dynamic Mechanical Properties ◽  
Hopkinson Pressure Bar ◽  
The Impact

Dynamic mechanical properties of silica fume concrete in a number of strain rate under the conditions of dynamic compression mechanical properties subjected to various strain rates were studied, and gained the stress versus strain curves, details of an experimental investigation using 74 mm-diameter split Hopkinson pressure bar(SHPB) apparatus were presented. The results showed that: The admixture of silica fume concrete impact resistance, especially under the impact of the performance of high-speed has a very important influence, with the impact velocity increased, the strain rate increase, and its impact more obvious.

scholarly journals Impact Behavior of Recycled Aggregate Concrete Based on Split Hopkinson Pressure Bar Tests

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yubin Lu ◽  
Xing Chen ◽  
Xiao Teng ◽  
Shu Zhang
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Impact Behavior ◽  
Hopkinson Pressure Bar ◽  
Aggregate Concrete ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
The Impact

This paper presents the experimental results of recycled aggregate concrete (RAC) specimens prepared with five different amounts of recycled coarse aggregate (RCA) (i.e., 0, 25%, 50%, 75%, and 100%) subjected to impact loading based on split Hopkinson pressure bar tests. Strain-rate effects on dynamic compressive strength and critical strain of RAC were studied. Results show that the impact properties of RAC exhibit strong strain-rate dependency and increase approximately linearly with strain-rate. The transition point from low strain-rate sensitivity to high sensitivity decreases with the increase of matrix strength.

Experimental Study on Compression Mechanical Properties of Aluminum Foams with Passive Confined Pressure

2013 ◽  
Vol 788 ◽  
pp. 147-151
Author(s):  
Cheng Bing Li ◽  
Jing You Chen
Keyword(s):  
Mechanical Properties ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Enhancement Effect ◽  
Hopkinson Pressure Bar ◽  
Aluminum Foams ◽  
Open Cell ◽  
The Impact

Abstract: Quasi-static and dynamic compression of open-cell and close-cell aluminum foams were investigated by MTS-809 material testing machine and Split Hopkinson Pressure Bar under the free state and passive confined pressure conditions. Experimental results indicate that the passive confined pressure has an important impact on quasi-static and dynamic compression mechanical properties of open-cell and close-cell aluminum foams. The enhancement effect of the passive confined pressure on close-cell aluminum foams is stronger than the impact on open-cell aluminum foams. The quasi-static and dynamic compression processes of aluminum foams consist of elastic stage, yield platform stage and compacting stage. The open-cell and close-cell aluminum foams investigated have strain rate sensitivity characteristics.

scholarly journals Fracture Characteristics and Geometric Fractal of Damaged Sandstone under Impact Load

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Hao Hu ◽  
Qiangqiang Zheng ◽  
Xin Gao ◽  
Bing Cheng ◽  
Qianqian Wang ◽  
...  
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Impact Load ◽  
Reduction Rate ◽  
Average Diameter ◽  
Rock Block ◽  
Damage Factor ◽  
Hopkinson Pressure Bar ◽  
Fracture Characteristics ◽  
Before And After ◽  
The Impact

Before the rock mass in the engineering is broken under load, it is usually in a state of varying degrees of damage. Aiming at the fracture characteristics of damaged sandstone under impact load, this paper adopts a method of the cyclic static load to cause the sandstone specimens to have varying degrees of damage. Then, the wave velocity of sandstone before and after the damage is measured using the nonmetallic acoustic velocimeter, and the change rule of damage factor is analyzed. Finally, the split Hopkinson pressure bar (SHPB) is used to test the impact dynamics of sandstone with different damage degrees. The broken rock block is screened by a vibrating screen, and the crushing characteristics are analyzed. The results show that not only the damage factor of damaged sandstone but the growth rate increases, with the raising upper limit of stress. Under the impact load of the same incident energy, the fragmentation degree of the damaged sandstone increases with the increase of the upper stress limit, while the average diameter of the broken rock block decreases gradually, and the reduction rate increases first and then decreases.

scholarly journals Dynamic Compressive Strength Tests of Corroded SFRC Exposed to Drying–Wetting Cycles with a 37 mm Diameter SHPB

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2267
Author(s):  
Hui Chen ◽  
Xiangqiang Zhou ◽  
Qiang Li ◽  
Rui He ◽  
Xin Huang
Keyword(s):  
Strain Rate ◽  
Steel Fiber ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Strain Curve ◽  
Fiber Reinforced Concrete ◽  
Impact Compression ◽  
Dynamic Increase Factor ◽  
Compression Performance ◽  
The Impact

This study focuses on the dynamic compression performance of corroded steel fiber-reinforced concrete (SFRC) exposed to drying–wetting chloride cycles by a 37 mm diameter split Hopkinson pressure bar (SHPB) system. Three steel fiber contents (0.5%, 1.0%, 2.0%, by volume) were incorporated into concrete, and samples were subjected to drying–wetting cycles for different corrosion durations (30 days, 60 days, 90 days) after 28 days age. The sample damage mode, stress–strain curve and the dynamic compression performance of corroded SFRC were compared with plain concrete. Through the experimental data, strain-rate effect, fiber reinforcement effect and the corrosion duration influence on the impact compression property of SFRC were identified. The dynamic increase factor results of these samples were compared with the existing models in previous published literature. An empirical dynamic increase factor profile characterization model considering fiber content, corrosion duration and strain-rate is proposed.

Analysis of the Impact of the Frequency Range of the Tensometer Bridge and Projectile Geometry on the Results of Measurements by the Split Hopkinson Pressure Bar Method

2013 ◽  
Vol 20 (4) ◽  
pp. 555-564 ◽  
Author(s):  
Wojciech Moćko
Keyword(s):  
Test Bench ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Deformation ◽  
Spectral Width ◽  
Hopkinson Pressure Bar ◽  
Computing Environment ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
The Impact ◽  
Bench Model

Abstract The paper presents the results of the analysis of the striker shape impact on the shape of the mechanical elastic wave generated in the Hopkinson bar. The influence of the tensometer amplifier bandwidth on the stress-strain characteristics obtained in this method was analyzed too. For the purposes of analyzing under the computing environment ABAQUS / Explicit the test bench model was created, and then the analysis of the process of dynamic deformation of the specimen with specific mechanical parameters was carried out. Based on those tests, it was found that the geometry of the end of the striker has an effect on the form of the loading wave and the spectral width of the signal of that wave. Reduction of the striker end diameter reduces unwanted oscillations, however, adversely affects the time of strain rate stabilization. It was determined for the assumed test bench configuration that a tensometric measurement system with a bandwidth equal to 50 kHz is sufficient

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