Effect of fiber types on the electrical properties of fiber reinforced concrete

2020 ◽  
Vol 10 (5) ◽  
pp. 733-739
Author(s):  
Saman Hedjazi ◽  
Daniel Castillo
Keyword(s):  
Electrical Resistivity ◽  
Reinforced Concrete ◽  
Electrical Properties ◽  
Fiber Reinforced Concrete ◽  
Test Machine ◽  
Fiber Types ◽  
Fiber Reinforced ◽  
Volume Fractions ◽  
Concrete Properties ◽  
Special Cases

Using fibers in concrete, has been recognized as a practical method to improve concrete properties such as reduction in crack development and higher resistance against impact and abrasion. Dry cementitious material exhibits very high electrical resistivity. However, fibers can significantly decrease the electrical resistivity of concrete which affects its insulating nature and has negative effects on concrete properties such as durability and also in special cases such as rail road ties production. In this paper the effect of steel, glass, and nylon fiber on the electrical properties of Fiber Reinforced Concrete (FRC) is investigated. Six different fiber volume fractions (Vf) (0.10% vol., 0.25% vol., 0.50% vol., 0.75% vol., 1.00% vol., 1.50% vol.) and several water-to-cement ratios (w/c) were considered as the main variables in the present study. In order to test the electrical properties of FRC, 100 mm × 200 mm cylinders were casted, cured and tested. The four point technique was used for measuring the surface electrical resistivity of concrete after curing in water for 3, 7, 28, and 44 days. Additionally, the compressive strength of each specimen was determined experimentally using the Compression Test Machine. The results revealed that the electrical resistivity of FRC decreases with an increase in fiber content but different types of fibers have different electrical effects on concrete. The effects of different volume fractions of three fiber types, together with different concrete mix proportions are presented and discussed.

scholarly journals Damage Evolution of Steel-Polypropylene Hybrid Fiber Reinforced Concrete: Experimental and Numerical Investigation

2018 ◽  
Vol 2018 ◽  
pp. 1-23
Author(s):  
Lihua Xu ◽  
Cuimei Wei ◽  
Biao Li
Keyword(s):  
Reinforced Concrete ◽  
Damage Evolution ◽  
Fiber Reinforced Concrete ◽  
Stiffness Degradation ◽  
Fiber Types ◽  
Peak Strain ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Volume Fractions ◽  
Aspect Ratios

This paper presents an experimental investigation on the stress-strain behavior and damage evolution of steel-polypropylene hybrid fiber reinforced concrete (HFRC) with different fiber types, volume fractions, and aspect ratios. The damage evolution laws of HFRC were obtained using uniaxial cyclic compression and tension tests. The results show that the addition of hybrid fiber has a significant synergetic effect on the mechanical behavior of concrete. The peak strength, peak strain, toughness, and postpeak ductility of HFRC under both tension and compression are improved, and the damage accumulation and stiffness degradation are alleviated by increasing volume fractions of SF and PF, as well as aspect ratios of SF. Moreover, the steel fiber volume fraction shows a more pronounced effect than that of other considered factors on the enhancement of cyclic mechanical parameters of HFRC. Based on the unloading stiffness degradation process, analytical equations were, respectively, proposed to generalize the damage progression of HFRC under compression and tension, with the effects of hybrid fiber taken into consideration. Finally, the proposed uniaxial damage evolution equations combined with the calibrated concrete damaged plasticity (CDP) model in ABAQUS were used to predict the responses of HFRC materials and structural members subjected to shear and seismic loads. The comparisons between the numerical predictions and experimental results show a good agreement.

Moisture Effects on Cellulose Fiber Reinforced Concrete Properties

2013 ◽  
Vol 330 ◽  
pp. 77-81
Author(s):  
Yu Chen ◽  
David Bloomquist ◽  
Raphael Crowley
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Yield Strength ◽  
Cellulose Fiber ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Concrete Properties ◽  
Moisture Effects ◽  
Strength Tests ◽  
Effect Of Moisture

ASTM C78, the Flexural Strength tests were conducted on Cellulose Fiber Reinforced Concrete (CFRC) samples subjected to difference moisture-levels to quantify the effect of moisture on them. Results indicated that modulus elasticity did not change along the increase in moisture. However, flexural strength and yield strength appeared to be affected under certain conditions.

Experimental Study on Rate-Dependent of the Bending Tensile Properties for Steel Fiber Reinforced Concrete

2011 ◽  
Vol 71-78 ◽  
pp. 1083-1089
Author(s):  
Zhang Luo
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Strain Rate ◽  
Tensile Properties ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Test Machine ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Rate Dependent

Extensive experimental research has been done on rate-dependent properties normal concrete, but very little on the tensile properties of steel fiber reinforced concrete (SFRC). In this article, based on a high-speed Instron servo-controlled hydraulic materials test machine is adopted to investigate the strain rate-dependent properties of bending tensile properties for SFRC. The scheme of experiment, the works of specimens fabricating and the processes of both loading and measuring were introduced. A total of 30 beam specimens are tested. The steel fiber content is varied: 0%, 1.0%, 2.0%, 3.0% and 4.0% by volume. The experimental results were analyzed. The emphasis is put on the study of the flexural strength changes of SFRC under different strain rates. It is discovered that, with the improvement of the strain rate, increasing strength of SFRC is very obvious. While the strain rate increases from 1.4×10-4s-1 to 0.53×10-4s-1, the flexural strength increasing around 30%.

Effect of Polypropylene Fiber on the Properties of Cement Mortar

2014 ◽  
Vol 919-921 ◽  
pp. 1903-1907
Author(s):  
Jun Pan ◽  
Fei Li ◽  
Xue Wu Zhang
Keyword(s):  
Reinforced Concrete ◽  
Fly Ash ◽  
Cement Mortar ◽  
Polypropylene Fiber ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Fiber Types ◽  
Fiber Reinforced ◽  
Bending Tests ◽  
Reinforced Cement

This thesis discusses the influence of fly ash content, fiber content and fiber types on the performance of fiber reinforced concrete, through the flexural and compressive tests on fiber reinforced cement mortar, and the splitting tensile and bending tests on the fiber reinforced concrete. The test result shows that the adding of fly ash can better play the enhancement of polypropylene fiber; the change of the fiber content affects the flexural strength of cement mortar and obviously improves the splitting tensile strength of the reinforced concrete; and the polypropylene fiber and steel fiber have different enhancement on cement mortar due to their qualitative differences.

Relationships between mechanical and transport properties for fiber reinforced concrete

2011 ◽  
Vol 46 (13) ◽  
pp. 1607-1615 ◽  
Author(s):  
Byoungil Kim ◽  
Jung-Youn Lee
Keyword(s):  
Reinforced Concrete ◽  
Transport Properties ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Types ◽  
Matrix Interface ◽  
Transport Mechanisms ◽  
Fiber Reinforced ◽  
Capillary Action ◽  
The Matrix

This study investigated the mechanical and transport properties of the important factors of fiber-reinforced concrete (FRC) for the design of durable concrete structures. The fibers that are commonly used in industry, such as 1% steel, 0.5% polypropylene (PP), and 0.75% polyvinyl alcohol (PVA) fibers, were evaluated. The addition of PP, PVA, and steel fibers, as they have been known, had little or no effect on compressive and tensile strengths but significantly affected postcracking behaviors and the critical transport mechanisms. The change of the permeable pores seems to depend on the material property of fibers between the fiber and the matrix interface. Among the fiber types used in this study, hook end steel fibers showed the best performance for both the mechanical and transport properties. Generally, as the permeable pore spaces increased, the strength as well as the resistance of transport properties also decreased. However, the effect of the permeable voids on the transport properties was much greater than that of the compressive strength. When the transport properties obtained are employed for the design of durable FRC, major properties such as the permeable voids and absorption by capillary action are important factors to be considered first for resisting movement of harmful substances into concrete.

scholarly journals Fiber Interfacial Transition Zone Concept for Steel Fiber-Reinforced Concrete by SEM Observation

2021 ◽  
Vol 19 (4) ◽  
pp. 294-307
Author(s):  
Ehsan Adili ◽  
Ali Kheyroddin
Keyword(s):  
Reinforced Concrete ◽  
Transition Zone ◽  
Sem Analysis ◽  
Interfacial Transition Zone ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Types ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Crack Widths

Fiber-reinforced concrete (FRC), which has become quite popular in recent years, improves many of concrete’s mechanical properties. It uses fibers discretely and is utilized in different structures. This paper proposes, between steel fibers and concrete, a fiber interfacial transition zone (FITZ) which is the most vulnerable part of steel FRC (SFRC) because it has a high cracking and microcracking potential due to fiber-concrete separation. In the prepared specimens, steel fibers were added to concrete in hooked and twisted forms, the SFRC microstructure was studied in both cases under a scanning electron microscope (SEM), and the related images were compared as secondary electron (SE) images. The SEM analysis showed highly precise images of the cracks and their microstructures in the FITZ and lab results show that the newly defined FITZ illustrates the cracking patterns well for both fiber types. Because twisted fibers have cracking angles and larger contact surfaces, the concrete-fiber bond is increased and the related crack widths decrease considerably. A comparison of the crack widths showed that those in the FITZ of specimens with twisted fibers decreased by a factor of approximately seven compared to those with hooked fibers.

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