scholarly journals Interface Bond Characterization between Fiber and Cementitious Matrix

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Won-Chang Choi ◽  
Seok-Joon Jang ◽  
Hyun-Do Yun
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Fiber Type ◽  
Polypropylene Fiber ◽  
Interfacial Properties ◽  
Design Parameters ◽  
Cement Matrix ◽  
Cementitious Matrix ◽  
Pull Out ◽  
Binder Ratio

The use of high performance composite fibers allows for the improvement of the mechanical properties of cement composites. Previous research results indicate that the mechanical properties of such composites are determined predominantly by the interface properties between the fiber and cementitious matrix. Many researchers have conducted single-fiber pull-out tests using cementitious composites to quantify the interfacial properties between the fiber and cement matrix. This paper aims to establish a design methodology that employs coefficients to represent the design parameters for the interfacial properties for three types of fibers: carbon fiber, polypropylene fiber, and twisted wire strand steel cord. The parameters for each type of fiber include the water-to-binder ratio and fiber embedment length. The adopted equation used for the numerical analysis was calibrated using experimental data, and design coefficients are proposed accordingly. The developed models could be validated successfully, and the pull-out characteristics of each fiber type are presented.

Microscopic Analysis and Study of High-Performance Seawater All-Coral Concrete

2019 ◽  
Vol 815 ◽  
pp. 216-222
Author(s):  
Chao Chen ◽  
Jin Ming Liu ◽  
Yang Yang ◽  
Zhi Guo Guo
Keyword(s):  
Mechanical Properties ◽  
Natural Environment ◽  
High Performance ◽  
Work Performance ◽  
Room Temperature ◽  
Microscopic Analysis ◽  
Internal Curing ◽  
Mix Design ◽  
Binder Ratio ◽  
Water To Binder Ratio

The ocean islands are far from inland and the concrete sandstone aggregates are scarce. In this paper, high-performance seawater all-coral concrete was developed by seawater mixing and room temperature maintenance design, and by optimizing the water-to-binder ratio, regulating internal curing, changing auxiliary cementing materials and blending ratio, incorporating expansion agent, adjusting fiber blending, etc. Combined with the consideration of work performance and mechanical properties, the concrete self-shrinkage is adjusted to further optimize the mix design. The mechanical properties of the optimized high-performance seawater all-coral concrete were studied, and the relevant durability tests were carried out according to the natural environment characteristics of the island. This is of great significance to the construction of island projects, repair and construction, and construction of protective projects [1].

scholarly journals Characteristics of Recycled Polypropylene Fibers as an Addition to Concrete Fabrication Based on Portland Cement

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1827 ◽  
Author(s):  
Marcin Małek ◽  
Mateusz Jackowski ◽  
Waldemar Łasica ◽  
Marta Kadela
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Polypropylene Fibers ◽  
Split Tensile Strength ◽  
Recycled Polypropylene ◽  
Recycled Fibers

High-performance concrete has low tensile strength and brittle failure. In order to improve these properties of unreinforced concrete, the effects of adding recycled polypropylene fibers on the mechanical properties of concrete were investigated. The polypropylene fibers used were made from recycled plastic packaging for environmental reasons (long degradation time). The compressive, flexural and split tensile strengths after 1, 7, 14 and 28 days were tested. Moreover, the initial and final binding times were determined. This experimental work has included three different contents (0.5, 1.0 and 1.5 wt.% of cement) for two types of recycled polypropylene fibers. The addition of fibers improves the properties of concrete. The highest values of mechanical properties were obtained for concrete with 1.0% of polypropylene fibers for each type of fiber. The obtained effect of an increase in mechanical properties with the addition of recycled fibers compared to unreinforced concrete is unexpected and unparalleled for polypropylene fiber-reinforced concrete (69.7% and 39.4% increase in compressive strength for green polypropylene fiber (PPG) and white polypropylene fiber (PPW) respectively, 276.0% and 162.4% increase in flexural strength for PPG and PPW respectively, and 269.4% and 254.2% increase in split tensile strength for PPG and PPW respectively).

scholarly journals PLASMA MODIFICATION OF MICROFIBERS - APPLICATION TO LIGHTWEIGHT CEMENT COMPOSITE CONTAINING RECYCLED CONCRETE

2021 ◽  
Vol 30 ◽  
pp. 7-11
Author(s):  
Jakub Ďureje ◽  
Zdeněk Prošek ◽  
Jan Trejbal ◽  
Pavel Tesárek ◽  
Štěpán Potocký
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Oxygen Plasma ◽  
Cement Composite ◽  
Recycled Concrete ◽  
Plasma Modification ◽  
Cement Matrix ◽  
Foaming Agent ◽  
Cementitious Matrix

The article deals with the optimalization of composition for reinforced lightweight cement composite containing micronized recycled concrete, which will be used to produce masonry blocks. The composite material is reinforced with polypropylene microfibers. To increase the cohesion between the fibers and the cementitious matrix, the optimal modification using oxygen plasma was chosen. Furthermore, a suitable foaming agent was chosen to lighten the cement matrix. A suitable ratio of cement and micronized recycled concrete was determined. Finally, a cement composite was made from the optimized components. The mechanical properties of this composite were tested. The resulting mechanical properties of the lightweight samples were compared with the non-light samples.

scholarly journals On enhancing the mechanical behavior of ultra-high performance concrete through multi-scale fiber reinforcement

2021 ◽  
Author(s):  
Ketan Ragalwar ◽  
William Heard ◽  
Brett Williams ◽  
Dhanendra Kumar ◽  
Ravi Ranade
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Underlying Mechanism ◽  
Steel Fibers ◽  
Flexural Behavior ◽  
Steel Wool ◽  
Multi Scale ◽  
Pull Out ◽  
Fiber Matrix

Steel fibers are typically used in ultra-high performance concretes (UHPC) to impart flexural ductility and increase fracture toughness. However, the mechanical properties of the steel fibers are underutilized in UHPC, as evidenced by the fact that most of the steel fibers pull out of a UHPC matrix largely undamaged during tensile or flexural tests. This research aims to improve the bond between steel fibers and a UHPC matrix by using steel wool. The underlying mechanism for fiber-matrix bond improvement is the reinforcement of the matrix tunnel, surrounding the steel fibers, by steel wool. Single fiber pullout tests were performed to quantify the effect of steel wool content in UHPC on the fiber-matrix bond. Microscopic observations of pulled-out fibers were used to investigate the fiber-matrix interface. Compared to the control UHPC mixture with no steel wool, significant improvement in the flexural behavior was observed in the UHPC mixtures with steel wool. Thus, the addition of steel wool in steel fiber-reinforced UHPC provides multi-scale reinforcement that leads to significant improvement in fiber-matrix bond and mechanical properties of UHPC.

An Experimental Study on Evaluation of Mechanical Properties in High Performance Concrete Using Admixture

2013 ◽  
Vol 372 ◽  
pp. 231-234
Author(s):  
Jeong Eun Kim ◽  
Wan Shin Park ◽  
Nam Yong Eom ◽  
Sun Woong Kim ◽  
Do Gyeum Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Silica Fume ◽  
Modulus Of Elasticity ◽  
High Performance ◽  
High Performance Concrete ◽  
Splitting Tensile Strength ◽  
Experimental Investigations ◽  
Binder Ratio

In this study, some experimental investigations on the development of mechanical properties with age of high performance concrete (HPC) incorporated with blast furnace slag with fly ash or silica fume have been reported. Four different blended HPC were prepared in 0.40 water-binder ratio. At every four mixtures, the compressive strength, splitting tensile strength and modulus of elasticity at 7 and 28 days have been observed for HPC developments. Consequently, only replacement of silica fume significantly increases the mechanical properties in terms of compressive strength, splitting tensile strength and modulus of elasticity.

scholarly journals Finite Element Simulation of NiTiNb Shape Memory Alloy Pipe-Joint Subjected to Coupled Transformation and Plastic Deformation

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Xiang Chen ◽  
Bin Chen ◽  
Xianghe Peng ◽  
Xiaoqing Jin ◽  
Ying Ma ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
High Performance ◽  
Coupling Effect ◽  
Longitudinal Direction ◽  
Design Parameters ◽  
Pull Out ◽  
Pipe Joint

The assembling process of Ni47Ti44Nb9 alloy pipe joints considering the phase transformation and plasticity was numerically simulated for the first time with a developed constitutive model. The simulated process was based on the experimental material parameters, which were determined with the experimental tensile results of Ni47Ti44Nb9 shape memory alloy (SMA) and steel bars. The results showed that, after assembly, the Mises stress distributed uniformly along the longitudinal direction of the NiTiNb joint, but nonuniformly along the radial direction. The maximum σeq does not appear at the inner wall of the joints due to the coupling effect of the plastic deformation and the recoverable transformation. The contact pressure distributed uniformly along the circumferential direction, but nonuniformly along the longitudinal direction. The sizes of the SMA joint and the pipe should be properly matched to ensure contact during the stage of the rapid reverse phase transformation to obtain stable connection performance. The pull-out force was also computed, and the results were in good agreement with the experimental results. The results obtained can provide available information for the optimization of the design parameters of the high-performance SMA pipe-joint, such as inner diameter and assembly clearance.

Interfacial Debonding and Sliding in Brittle Cementmatrix Composites from Steel Fiber Pullout Tests

1994 ◽  
Vol 370 ◽  
Author(s):  
M. Jamal Shannag ◽  
Will Hansen ◽  
Rune Brincker
Keyword(s):  
High Performance ◽  
Volume Fraction ◽  
Particle System ◽  
Interfacial Properties ◽  
Test Method ◽  
Cement Matrix ◽  
Fiber Volume ◽  
Fiber Pullout ◽  
Plastic Tube ◽  
Embedment Length

AbstractA specially designed single fiber pullout apparatus was used to provide simultaneous results on total fiber displacement versus load in addition to monitoring the fiber displacement at the free end. In this apparatus the fiber was going through the entire specimen, which made it possible to determine the point of complete debonding. To control the embedment length a plastic tube was inserted around the fiber. The described fiber pullout test method coupled with an appropriate analysis provides a quantitative determination of interfacial properties which are relevant to toughening of brittle materials through fiber-reinforcement. The technique was used on a high strength cement-based matrix called the Densified Small Particle system (DSP), and on an ordinary strength matrix. Other parameters investigated included fiber embedment length and fiber volume fraction in the cement matrix. The results indicate that: (1) the dense DSP matrix has significantly improved interfacial properties as compared to the ordinary strength matrix; (2) the major energy of pullout in both systems is due to sliding; and (3) both the debonding energy and sliding energy increase with fiber embedment length. These results are important in the understanding of the role of steel fibers in improving the tensile properties of high performance fiber reinforced composites.

scholarly journals Optimizing the Mechanical Properties of Ultra-High-Performance Fibre-Reinforced Concrete to Increase Its Resistance to Projectile Impact

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5098
Author(s):  
Anna L. Mina ◽  
Konstantinos G. Trezos ◽  
Michael F. Petrou
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Fibre Reinforced Concrete ◽  
Direct Tension ◽  
Steel Fibres ◽  
Projectile Impact ◽  
Binder Ratio ◽  
High Performance Fibre

This study describes an extensive experimental investigation of various mechanical properties of Ultra-High-Performance Fibre-Reinforced Concrete (UHPFRC). The scope is to achieve high strength and ductile behaviour, hence providing optimal resistance to projectile impact. Eight different mixtures were produced and tested, three mixtures of Ultra-High-Performance Concrete (UHPC) and five mixtures of UHPFRC, by changing the amount and length of the steel fibres, the quantity of the superplasticizer, and the water to binder (w/b) ratio. Full stress–strain curves from compression, direct tension, and flexural tests were obtained from one batch of each mixture to examine the influence of the above parameters on the mechanical properties. The Poisson’s ratio and modulus of elasticity in compression and direct tension were measured. Additionally, a factor was determined to convert the cubic strength to cylindrical. Based on the test results, the mixture with high volume (6%) and a combination of two lengths of steel fibres (3% each), water to binder ratio of 0.16% and 6.1% of superplasticizer to binder ratio exhibited the highest strength and presented great deformability in the plastic region. A numerical simulation developed using ABAQUS was capable of capturing very well the experimental three-point bending response of the UHPFRC best-performed mixture.

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