scholarly journals Effect of Carbon Black and Hybrid Steel-Polypropylene Fiber on the Mechanical and Self-Sensing Characteristics of Concrete Considering Different Coarse Aggregates’ Sizes

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7455
Author(s):  
Shakeel Ahmed ◽  
Abasal Hussain ◽  
Zahoor Hussain ◽  
Zhang Pu ◽  
Krzysztof Adam Ostrowski ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Carbon Black ◽  
Steel Fiber ◽  
Crack Opening ◽  
Polypropylene Fiber ◽  
The Self ◽  
Filler Materials ◽  
Multiple Cracks ◽  
Cracking Behavior ◽  
Coarse Aggregates

The effect of combining filler (carbon black) and fibrous materials (steel fiber and polypropylene fiber) with various sizes of coarse particles on the post-cracking behavior of conductive concrete was investigated in this study. Steel fibers (SF) and carbon black (CB) were added as monophasic, diphasic, and triphasic materials in the concrete to enhance the conductive properties of reinforced concrete. Polypropylene fiber (PP) was also added to steel fiber and carbon to improve the post-cracking behavior of concrete beams. This research mainly focused on the effects of macro fibers on toughness parameters and energy absorption capacity, as well as enhancing the self-sensing of multiple cracks and post-cracking behavior. Fractional changes in resistance and crack opening displacement (COD-FCR) and the relationship of load-deflection-FCR with different coarse aggregates of (5–10 mm and 15–20 mm) sizes were investigated, and the law of resistance signal changes with single and multiple cracking through load-time-FCR curves was explored. Results indicated that the smaller size coarse aggregates (5–10 mm) showed higher compressive strength: up to 8.3% and 14.83% with diphasic (SF + CB), respectively. The flexural strength of PC-10 increased 22.60 and 51.2%, respectively, with and without fibers, compared to PC-20. The diphasic and triphasic conductive material with the smaller size of aggregates (5–10 mm) increased the FCR values up to 38.95% and 42.21%, respectively, as compared to those of greater size coarse aggregates (15–20 mm). The hybrid uses of fibrous and filler materials improved post-cracking behavior as well as the self-sensing ability of reinforced concrete.

scholarly journals Effect of crack pattern on the self-healing capability in traditional, HPC and UHPFRC concretes measured by water and chloride permeability

2019 ◽  
Vol 289 ◽  
pp. 01006 ◽  
Author(s):  
Alberto Negrini ◽  
Marta Roig-Flores ◽  
Eduardo J. Mezquida-Alcaraz ◽  
Liberato Ferrara ◽  
Pedro Serna
Keyword(s):  
Reinforced Concrete ◽  
Water Permeability ◽  
High Performance ◽  
Water Immersion ◽  
Crack Pattern ◽  
The Self ◽  
Reinforced Concrete Beams ◽  
Multiple Cracks ◽  
Self Healing ◽  
High Performance Fibre

Concrete has a natural self-healing capability to seal small cracks, named autogenous healing, which is mainly produced by continuing hydration and carbonation. This capability is very limited and is activated only when in direct contact with water. High Performance Fibre-Reinforced Concrete and Engineered Cementitious Composites have been reported to heal cracks for low damage levels, due to their crack pattern with multiple cracks and high cement contents. While their superior self-healing behaviour compared to traditional concrete types is frequently assumed, this study aims to have a direct comparison to move a step forward in durability quantification. Reinforced concrete beams made of traditional, high-performance and ultra-high-performance fibre-reinforced concretes were prepared, sized 150×100×750 mm3. These beams were pre-cracked in flexion up to fixed strain levels in the tensioned zone to allow the analysis of the effect of the different cracking patterns on the self-healing capability. Afterwards, water permeability tests were performed before and after healing under water immersion. A modification of the water permeability test was also explored using chlorides to evaluate the potential protection of this healing in chloride-rich environments. The results show the superior durability and self-healing performance of UHPFRC elements.

scholarly journals Microscale Cohesive-Friction-Based Finite Element Model for the Crack Opening Mechanism of Hooked-End Steel Fiber-Reinforced Concrete

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 669
Author(s):  
Yassir M. Abbas
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Crack Opening ◽  
Fiber Reinforced Concrete ◽  
Embedment Depth ◽  
Fe Model ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Matrix

The entire mechanical properties of steel fiber-reinforced concrete (SFRC) are significantly dependent on the fiber–matrix interactions. In the current study, a finite element (FE) model was developed to simulate the pullout response of hooked-end SFRC employing cohesive–frictional interactions. Plain stress elements were adapted in the model to exemplify the fiber process constituents, taking into consideration the material nonlinearity of the hooked-end fiber. Additionally, a surface-to-surface contact model was used to simulate the fiber’s behavior in the pullout mechanism. The model was calibrated against experimental observations, and a modification factor model was proposed to account for the 3D phenomenalistic behavior of the pullout behavior. Realistic predictions were obtained by using this factor to predict the entire pullout-slip curves and independent results for the peak pullout load. The numerical results indicated that the increased fiber diameter would alter the mode of crack opening from fiber–matrix damage to that combined with matrix spalling, which can neutralize the sensitivity of the entire pullout response of hooked-end steel fiber to embedment depth. Additionally, the fiber–matrix bond was enhanced by increasing the fiber’s surface area, sensibly leading to a higher pullout peak load and toughness. The developed FE model was also proficient in predicting microstructural stress distribution and deformations during the crack opening of SFRC. This model could be extended to fully model a loaded SFRC composite material by the inclusion of various randomly oriented dosages of fibers in the concrete block.

Mechanical Properties of Fiber Reinforced Self-Compacting Concrete

2013 ◽  
Vol 470 ◽  
pp. 797-801 ◽  
Author(s):  
Wu Jian Long ◽  
Han Xin Lin ◽  
Zhen Rong Chen ◽  
Kai Long Zhang ◽  
Wei Lun Wang
Keyword(s):  
Compressive Strength ◽  
Steel Fiber ◽  
Polypropylene Fiber ◽  
Performance Testing ◽  
The Self ◽  
Self Compacting Concrete ◽  
Curing Period ◽  
Polyethylene Fiber ◽  
Mechanics Performance ◽  
Mechanical Strengths

The mechanical strengths of self-compacting concrete (SCC) with different strengths and different fibers were investigated. By mechanics performance testing on concrete samples, it shows that the fiber can significantly reduce strength of the self-compacting concrete during curing period. The 28d tensile strength of self-compacting concrete can be improved when steel fiber, polypropylene fiber, or polyethylene fiber were used. Moreover, steel fiber can improve the 28d compressive strength; contrarily, polypropylene fiber and polyethylene fiber can reduce the 28d compressive strength.

scholarly journals Research on compressive strength of hybrid fiber reinforced concrete based on orthogonal design

2021 ◽  
Vol 261 ◽  
pp. 02019
Author(s):  
Tu-Sheng He ◽  
Meng-Qian Xie ◽  
Yang Liu ◽  
San-Yin Zhao ◽  
Zai-Bo Li
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Prediction Model ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Concrete Compressive Strength ◽  
Hybrid Fiber

The influence of steel fiber and polypropylene fiber mixed on compressive strength of high performance concrete (HPC) was studied. The steel fiber content (0.5%, 1.0%, 1.5%, 2.0%) (volume fraction, the same below), polypropylene fiber content (0.05%, 0.1%, 0.15%, 0.2%) and length (5mm, 6.5mm, 12mm, 18mm) were studied by L16 (45) orthogonal test for 28d ages, the range analysis and variance analysis of the test results are carried out, and the prediction model of compressive strength of hybrid fiber reinforced concrete was established. The results show that: The significant influence factor of concrete compressive strength is the volume fraction of polypropylene fiber, while the length of polypropylene fiber and the volume fraction of steel fiber are not significant; the concrete compressive strength with polypropylene fiber shows negative hybrid effect; The prediction model of compressive strength of hybrid fiber reinforced concrete has high accuracy, and the average relative errors is 2.96%.

scholarly journals Tension Stiffening Behavior of Polypropylene Fiber- Reinforced Concrete Tension Members

2021 ◽  
Vol 53 (2) ◽  
pp. 210209
Author(s):  
Aris Aryanto ◽  
Berto Juergen Winata
Keyword(s):  
Reinforced Concrete ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Polypropylene Fibers ◽  
Fiber Reinforced ◽  
Tension Stiffening ◽  
Cracking Behavior ◽  
Tension Members ◽  
Polypropylene Fiber Reinforced Concrete ◽  
Fiber Addition

This paper focuses on comparing the behavior of RC tension members with and without the addition of polypropylene fibers at various corrosion levels. Eight cylindrical tensile specimens were tested to evaluate their tension-stiffening and cracking behavior. The content of polypropylene fiber added into the concrete mix was the main variable (0.25%, 0.50%, 0.75%, and 1.0% of total volume). The corrosion level was varied from slight (5%), medium (10%) to severe (30%) and, like the other variables, applied only to 1.0% polypropylene fiber-reinforced concrete (PFRC) specimens. The test results showed that the fiber addition significantly increased the tension-stiffening effect but was largely unable to reduce the effect of bond degradation caused by corrosion. Moreover, the addition of polypropylene fibers was able to improve the cracking behavior in terms of crack propagation, as shown by smaller crack spacing compared to the specimen without fiber addition at the same corrosion level.

Experimental Study on Fracture Properties of Hybrid Fiber Reinforced Concrete

2012 ◽  
Vol 450-451 ◽  
pp. 518-522 ◽  
Author(s):  
Yun Da Shao ◽  
Wen Feng Wang
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Crack Tip Opening Displacement ◽  
Hybrid Fiber ◽  
Opening Displacement ◽  
Critical Crack ◽  
Fracture Properties

Though fracture test on the fifteen specimens with notch of hybrid fiber reinforced concrete with the size of 100mm×100mm×400mm, this paper explores the hybrid effect between steel fiber and polypropylene fiber and impact on the fracture properties, such as critical effective crack length, critical crack tip opening displacement, effective stress intensity factors and fracture energy. The test results indicate that the addition of fiber is helpful to improve the fracture properties of concrete. Synergistic effect of two kinds of fibers is good, the steel fiber with high elastic module can restrain the cracking of concrete when the crack displacement is small, polypropylene macro-fiber with high ductility is more beneficial to increase the fracture properties of concrete than steel fiber when the crack displacement is big. The best fiber compounding can be gotten when the volume fractions of steel fiber and polypropylene fiber is respectively 0.5％and 1.0％in this experiment.

scholarly journals Research on the Dynamic Mechanical Properties and Constitutive Models of Steel Fiber Reinforced Concrete and Polypropylene Fiber Reinforced Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Jie Huang ◽  
Yi Zhang ◽  
Yubin Tian ◽  
Hengheng Xiao ◽  
Jun Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Polypropylene Fiber ◽  
Dynamic Mechanical Properties ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Dynamic Mechanical ◽  
Polypropylene Fiber Reinforced Concrete

This paper presents the results of an experimental research designed to investigate the dynamic mechanical properties and constitutive model of fiber reinforced concrete (FRC), including steel fiber reinforced concrete (SFRC) and polypropylene fiber reinforced concrete (PFRC) under fast loading. Experimental results are achieved by using the electrohydraulic servo loading test method, implying that the dynamic mechanical properties of PFRC and SFRC, such as peak stress, peak strain, and toughness, are positively affected by strain rate. The experimental elastic modulus test results of FRC with different fiber contents indicate that the elastic modulus is positively affected by polypropylene or steel fibers and increases with the increment of fiber content. Finally, the experimental stress-strain curves obtained in the MTS electrohydraulic servo system test are fitted by a damage dynamic constitutive model of FRC. The good fitting with experimental results proves that the model could be appropriate to describe the dynamic mechanical properties of FRC.

Synergistic Effects and Cracking Bending Strength for Steel-Polypropylene Hybrid Fiber Reinforced Concrete

2013 ◽  
Vol 652-654 ◽  
pp. 1237-1241
Author(s):  
Guo Dong Mei ◽  
Xiao Fan Liu ◽  
Ji Xiang Li ◽  
Wen Fu Duan
Keyword(s):  
Reinforced Concrete ◽  
Synergistic Effect ◽  
Bending Strength ◽  
Steel Fiber ◽  
Synergistic Effects ◽  
Polypropylene Fiber ◽  
Plain Concrete ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Hybrid Fiber

The cracking bending strength for steel-polypropylene hybrid fiber reinforced concrete (HFRC) had been studied based on experimental test. the inicial cracking strength achieve significant improvement compare to plain concrete, and the highest increase is 16.7%. There is a synergistic effect exist when steel fiber is 1.0% in volume or polypropylene fiber is 0.1% in volume, and the synergistic effect raise to vertex (1.043) when both of those two requirements are fulfilled.

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