scholarly journals Influence of MgO and Hybrid Fiber on the Bonding Strength between Reactive Powder Concrete and Old Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Mo Jinchuan ◽  
Ou Zhongwen ◽  
Wang Yahui
Keyword(s):  
Tensile Strength ◽  
Bonding Strength ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Drying Shrinkage ◽  
Splitting Tensile Strength ◽  
Reactive Powder Concrete ◽  
Fiber Volume ◽  
Reactive Powder

The reactive powder concrete (RPC) was used as concrete repair material in this paper. The influence of steel fiber, steel fiber + MgO, and steel fiber + MgO + polypropylene fiber (PPF) on the mechanical properties of RPC repair materials and the splitting tensile strength between RPC and old concrete was studied. Influences of steel fiber, MgO, and PPF on the splitting tensile strength were further examined by using scanning electronic microscopy (SEM) and drying shrinkage test. Results indicated that the compressive and flexural strength was improved with the increasing of steel fiber volume fraction. However, the bonding strength showed a trend from rise to decline with the increasing of steel fiber volume fraction. Although MgO caused mechanical performance degradation of RPC, it improved bonding strength between RPC and existing concrete. The influence of PPF on the mechanical properties of RPC was not obvious, whereas it further improved bonding strength by significantly reducing the early age shrinkage of RPC. Finally, the relationship of drying shrinkage and splitting tensile strength was studied, and the equation between the splitting tensile strength relative index and logarithm of drying shrinkage was obtained by function fitting.

Irradiation Duration Effect of Gamma Ray on the Compressive Strength of Reactive Powder Concrete

2020 ◽  
Vol 857 ◽  
pp. 15-21
Author(s):  
Nesreen B. Najib ◽  
Shatha D. Mohammed ◽  
Wasan Z. Majeed ◽  
Nada Mahdi Fawzi A. Jalawi
Keyword(s):  
Compressive Strength ◽  
Fiber Volume Fraction ◽  
Gamma Ray ◽  
Volume Fraction ◽  
Reactive Powder Concrete ◽  
Fiber Volume ◽  
Gamma Ray Irradiation ◽  
Duration Effect ◽  
Reactive Powder ◽  
The Impact

Reactive Powder Concrete (RPC) could be considered as the furthermost significant modern high compressive strength concrete. In this study, an experimental investigation on the impact of micro steel fiber volume fraction ratio and gamma ray irradiation duration influence upon the compressive strength of RPC is presented. Three volume fraction ratios (0.0, 1.0 and 1.5) % was implemented. For each percentage of the adopted fiber ratios, six different irradiation duration was considered; these are (1, 2, 3, 4, 5 and 6) days. Gamma source (Cs-137) of energy (0.662) MeV and activity (6) mci was used. In a case of zero volume fraction ratio, the experimental results showed that gamma ray had a significant influence on the reducing of the compressive strength varies between (1.2-8.6)% for a period of (1-6) days, respectively. Although there was a decrease in the compressive strength for a state of non-zero volume fraction ratio (1 and 1.5) % varies between (1.0-3.1 and 0.4-1.6) %, respectively, the attained results indicated that gamma ray had no significant effect to reduce the compressive strength of the RPC that’s included micro steel fibers as a volume fraction.

scholarly journals Evaluation of the Ultimate Strength of the Ultra-High-Performance Fiber-Reinforced Concrete Beams

2021 ◽  
Vol 11 (7) ◽  
pp. 2951
Author(s):  
Baek-Il Bae ◽  
Moon-Sung Lee ◽  
Chang-Sik Choi ◽  
Hyung-Suk Jung ◽  
Hyun-Ki Choi
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Ultimate Strength ◽  
High Performance ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Fiber Volume ◽  
High Performance Fiber

Evaluation of the ultimate strength for the UHPFRC (ultra-high-performance fiber-reinforced concrete) flexural members was conducted. In this study, an experimental program about UHPFRC beams was conducted with the effect of fiber volume fraction, shear span to depth ratio, and compressive strength of matrix as the main variables. Among them, it was found that fiber volume fraction was the variable that had the greatest influence on the ultimate strength. The inclusion of 2% volume fraction steel fiber increases the shear and flexural strength of UHPFRC beams significantly. In particular, steel fiber inclusion changed the mode of failure of beams from diagonal shear failure into flexural failure. For the classification of failure patterns, the ultimate flexural strength and shear strength of UHPFRC members were evaluated using the current design code and UHPC guidelines. Flexural ultimate strength was affected by the size and shape of the stress block and consideration of the matrix’s tensile strength. For the accurate shear strength prediction of UHPFRC beams, the tensile strength of the high strength matrix and the effect of steel fiber should be considered.

Effect of Polypropylene Fiber on Mechanical Properties of Concrete Containing Fly Ash

2011 ◽  
Vol 346 ◽  
pp. 26-29 ◽  
Author(s):  
Hong Wei Wang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Modulus Of Elasticity ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Splitting Tensile Strength ◽  
Fiber Volume

A designed experimental study has been conducted to investigate the effect of the fiber fraction of polypropylene fiber on the mechanical properties of concrete containing fly ash, a large number of experiments have been carried out in this study. The mechanical properties include compressive strength, splitting tensile strength and compressive modulus of elasticity. On the basis of the experimental results of the specimens of six sets of mix proportions, the mechanism of action of polypropylene fiber on these mechanical properties has been analyzed in details. The results indicate that there is a tendency of increase in the compressive strength and splitting tensile strength, and the modulus of elasticity of concrete containing fly ash decrease gradually with the increase of fiber volume fraction with appropriate content.

Research on Strength of Steel Fiber Reinforced Concrete at Low Fiber Volume Fraction Based on Binary Variance Analysis

2013 ◽  
Vol 742 ◽  
pp. 243-248
Author(s):  
Jian Song Yuan ◽  
Dan Ying Gao ◽  
Lin Yang
Keyword(s):  
Tensile Strength ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Concrete Strength ◽  
Volume Ratio ◽  
Fiber Reinforced Concrete ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Volume ◽  
Split Tensile Strength

Based on the strength tests, including compressive strength, split tensile strength, shear strength , of steel fiber reinforced concrete (SFRC) with different concrete strength grades (C20~C50) at low fiber volume fraction (0~0.7%), the influences of concrete strength grades and steel fiber volume on concrete strengths were studied, and the effect significance levels of the two factors was analyzed through the binary variance analysis. The results show that when the concrete strength grades are amongst C20 ~ C50 and steel fiber volume rates lie in the range 0~0.7%,the strengths of SFRC rises as concrete strength grade and steel fiber volume ratio increase ; the influence of concrete grade is more significant than that of steel fiber volume ratio on compressive strength and split tensile strength of SFRC; the influence of steel fiber volume fraction is less significant than that of concrete strength grades on shear strength of SFRC.

scholarly journals Influence of Cooling Methods on the Behavior of Reactive Powder Concrete Exposed to Fire Flame Effect

Fibers ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 19
Author(s):  
Hadeel K. Awad
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Volume Fraction ◽  
Splitting Tensile Strength ◽  
Reactive Powder Concrete ◽  
Absorbed Energy ◽  
Fire Flame ◽  
Reactive Powder ◽  
Cooling Methods

The construction of highly safe and durable buildings that can bear accident damage risks including fire, earthquake, impact, and more, can be considered to be the most important goal in civil engineering technology. An experimental investigation was prepared to study the influence of adding various percentages 0%, 1.0%, and 1.5% of micro steel fiber volume fraction (Vf) to reactive powder concrete (RPC)—whose properties are compressive strength, splitting tensile strength, flexural strength, and absorbed energy—after the exposure to fire flame of various burning temperatures 300, 400, and 500 °C using gradual-, foam-, and sudden-cooling methods. The outcomes of this research proved that the maximum reduction in mechanical properties is detected in case of 0% addition at burning temperature of 500 °C using sudden cooling to be 63.90%, 55.77% and 53.8% for compressive, splitting tensile, and flexural strength, respectively, while using 1.5% produced a modification in compressive strength, splitting tensile strength, and flexural strength to 6.67%, 4.15%, and 7.00% respectively, and 7.10 kN·mm for the absorbed energy for gradual cooling at 300 °C. From the results, the adopted cooling methods can be ordered according to their negative influence by sudden, foam, and gradual, while the optimum percentage of (Vf) is 1.5% when burning at 300 °C for all methods of cooling. 1.0% is considered the optimum percentage for all burning temperatures that exceed 400 °C using sudden-cooling method.

Performance of Bamboo Fiber Reinforced Composites: Mechanical Properties

2021 ◽  
Vol 879 ◽  
pp. 284-293
Author(s):  
Norliana Bakar ◽  
Siew Choo Chin
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Vinyl Ester ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Bamboo Fiber ◽  
Synthetic Fiber ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Volume Fractions

Fiber Reinforced Polymer (FRP) made from synthetic fiber had been widely used for strengthening of reinforced concrete (RC) structures in the past decades. Due to its high cost, detrimental to the environment and human health, natural fiber composites becoming the current alternatives towards a green and environmental friendly material. This paper presents an investigation on the mechanical properties of bamboo fiber reinforced composite (BFRC) with different types of resins. The BFRC specimens were prepared by hand lay-up method using epoxy and vinyl-ester resins. Bamboo fiber volume fractions, 30%, 35%, 40%, 45% and 50% was experimentally investigated by conducting tensile and flexural test, respectively. Results showed that the tensile and flexural strength of bamboo fiber reinforced epoxy composite (BFREC) was 63.2% greater than the bamboo fiber reinforced vinyl-ester composite (BFRVC). It was found that 45% of bamboo fiber volume fraction on BFREC exhibited the highest tensile strength compared to other BFRECs. Meanwhile, 40% bamboo fiber volume fraction of BFRVC showed the highest tensile strength between bamboo fiber volume fractions for BFRC using vinyl-ester resin. Studies showed that epoxy-based BFRC exhibited excellent results compared to the vinyl-ester-based composite. Further studies are required on using BFRC epoxy-based composite in various structural applications and strengthening purposes.

scholarly journals Tensile Mechanical Properties and Failure Modes of a Basalt Fiber/Epoxy Resin Composite Material

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Jingjing He ◽  
Junping Shi ◽  
Xiaoshan Cao ◽  
Yifeng Hu
Keyword(s):  
Tensile Strength ◽  
Composite Material ◽  
Fiber Volume Fraction ◽  
Failure Modes ◽  
Volume Fraction ◽  
Basalt Fiber ◽  
Orientation Angle ◽  
Fiber Volume ◽  
Fiber Clustering ◽  
Fiber Orientation Angle

Uniaxial tensile tests of basalt fiber/epoxy (BF/EP) composite material with four different fiber orientations were conducted under four different fiber volume fractions, and the variations of BF/EP composite material failure modes and tensile mechanical properties were analyzed. The results show that when the fiber volume fraction is constant, the tensile strength, elastic modulus, and limiting strain of BF/EP composite material all decrease with increasing fiber orientation angle. When the fiber orientation angle is constant, the tensile strength, elastic modulus, and limiting strain of BF/EP composite material all increase with increasing fiber volume fraction. A certain degree of fiber clustering appears in the epoxy resin when the basalt fiber volume fraction is >1.2%. The fiber equidistribution coefficient and clustering fiber content were used to characterize the basalt fiber clustering effect. With the increase of fiber volume fraction, the clustering fiber content gradually increased, but the fiber equidistribution coefficient decreased. Meanwhile, based on Tsai theory, a geometric model and a tensile mechanical model of the clustering fiber are established. By considering the fiber clustering effect, the BF/EP composite material tensile strength is calculated, and the calculated values are close to the experimental results.

scholarly journals Tensile Behavior Characteristics of High-Performance Slurry-Infiltrated Fiber-Reinforced Cementitious Composite with Respect to Fiber Volume Fraction

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3335 ◽  
Author(s):  
Seungwon Kim ◽  
Dong Joo Kim ◽  
Sung-Wook Kim ◽  
Cheolwoo Park
Keyword(s):  
Tensile Strength ◽  
Energy Absorption ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Absorption Capacity ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Energy Absorption Capacity ◽  
Direct Tensile ◽  
Direct Tensile Strength

Concrete has high compressive strength, but low tensile strength, bending strength, toughness, low resistance to cracking, and brittle fracture characteristics. To overcome these problems, fiber-reinforced concrete, in which the strength of concrete is improved by inserting fibers, is being used. Recently, high-performance fiber-reinforced cementitious composites (HPFRCCs) have been extensively researched. The disadvantages of conventional concrete such as low tensile stress, strain capacity, and energy absorption capacity, have been overcome using HPFRCCs, but they have a weakness in that the fiber reinforcement has only 2% fiber volume fraction. In this study, slurry infiltrated fiber reinforced cementitious composites (SIFRCCs), which can maximize the fiber volume fraction (up to 8%), was developed, and an experimental study on the tensile behavior of SIFRCCs with varying fiber volume fractions (4%, 5%, and 6%) was carried out through direct tensile tests. The results showed that the specimen with high fiber volume fraction exhibited high direct tensile strength and improved brittleness. As per the results, the direct tensile strength is approximately 15.5 MPa, and the energy absorption capacity was excellent. Furthermore, the bridging effect of steel fibers induced strain hardening behavior and multiple cracks, which increased the direct tensile strength and energy absorption capacity.

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