Mechanical Properties of Sprayable Fiber Reinforced Strain-Hardening Cement Composite (SHCC)

2013 ◽  
Vol 372 ◽  
pp. 211-214
Author(s):  
Zhong Jie Yu ◽  
Mi Hwa Lee ◽  
Hyun Do Yun
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Volume Fraction ◽  
Crack Opening ◽  
Cement Composite ◽  
Seismic Retrofitting ◽  
Mineral Admixtures ◽  
Uniaxial Tensile ◽  
High Expectations ◽  
The Subject

The use of strain-hardening cement composite (SHCC), which exhibits metal-like deformation behavior and has ability to restrict crack opening, as a retrofit material for seismic retrofitting of existing infrastructures, has been the subject of high expectations. In this work, Three SHCC mixtures including different chemical or mineral admixtures were prepared and evaluated based on the mechanical properties, such as flow, sprayability, compressive and uniaxial tensile performances. All SHCC mixtures were reinforced with polyvinyl alcohol (PVA) fibers at volume fraction of 2.2%. Mechanical properties of each SHCC mixture were measured and evaluated after mixing, pumping, and shotcreting. Experimental results indicated that the compressive strength and elastic modulus of three SHCC mixtures increased almost linearly according to shotcreting procedure from mixer to nozzle. And the uniaxial tensile of SHCC mixture (SHCC-AE) with AE agent was superior to the other SHCC mixtures (SHCC-MC and-N).

scholarly journals Effects of Shrinkage-Compensation on Mechanical Properties and Repair Performance of Strain-Hardening Cement Composite Materials

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Seok-Joon Jang ◽  
Sun-Woo Kim ◽  
Wan-Shin Park ◽  
Koichi Kobayashi ◽  
Hyun-Do Yun
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Volume Fraction ◽  
Cement Composite ◽  
Structural Performance ◽  
Rc Beam ◽  
Test Results ◽  
Fiber Volume ◽  
Study Results ◽  
Shrinkage Compensation

This paper describes the effects of expansive admixture on the mechanical properties of strain-hardening cement-based composite (SHCC) mixtures. Also, this study investigates structural performance of reinforced concrete (RC) beam specimens repaired with SHCC and Ex-SHCC (SHCC with expansive admixture). In this study, SHCC and Ex-SHCC mixtures with two specified compressive strength values of 30 MPa and 60 MPa and the fiber volume fraction of 1.5% were investigated. The expansive admixture replacement ratio of 10% by cement weight was used in this study. The test results indicate that the compressive, tensile, and flexural strength values of the SHCC mixtures increased when expansive admixture was included in the mix; however, their toughness and ductility decreased. The study results also show that the application of both SHCC and Ex-SHCC mixtures to repair damaged RC beam specimens can lead to significant structural performance improvement by mitigating crack damage and increasing ductility.

Cellulose Whiskers Micro-Fibers Effect in the Mechanical Proprieties of PP and PLA Composites Fibers Obtained by Spinning Process

2011 ◽  
Vol 146 ◽  
pp. 12-26 ◽  
Author(s):  
A. Gherissi ◽  
R.Ben Cheikh ◽  
E. Dévaux ◽  
Fethi Abbassi
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Tensile Tests ◽  
Advanced Materials ◽  
Uniaxial Tensile ◽  
Failure Resistance ◽  
Cellulose Whiskers ◽  
Limit Strength

In this study, we present the manufacturing process of two new composites materials in the form of long fibers of polylactic-acid (PLA) or polypropylene (PP), reinforced by cellulose whiskers micro-fibers loads. In order to evaluate the mechanical properties of these advanced materials, a several uniaxial tensile tests were carried out. The PP and the PLA have initially been spinning without the addition of cellulose whiskers micro-fibers. In order to study the effects of cellulose whiskers micro-fibers reinforcements in the Mechanical behavior of the PLA and PP filaments, we determinate the proprieties of these advanced material from the tensile results. For the PP composite filaments material case, the whiskers reinforcement increases Young's modulus and failure resistance, but it reduces the limit strength failure. For the PLA composites the addition of 1% wt of cellulose whiskers from the total volume fraction of the material, increase the Young’s modulus more than 50% and a decrease of the failure resistance and the limit strength of composite. The obtained composites fibers are very rigid and brittle. What follows, that the addition of cellulose whiskers micro fibers in PP matrix, provides mechanical properties more convenient compared to the PLA matrix.

scholarly journals Nanoparticle amount, and not size, determines chain alignment and nonlinear hardening in polymer nanocomposites

2017 ◽  
Vol 114 (16) ◽  
pp. E3170-E3177 ◽  
Author(s):  
H. Samet Varol ◽  
Fanlong Meng ◽  
Babak Hosseinkhani ◽  
Christian Malm ◽  
Daniel Bonn ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Polymer Nanocomposites ◽  
Nonlinear Elasticity ◽  
Volume Fraction ◽  
Uniaxial Tensile ◽  
Large Strains ◽  
Chain Alignment ◽  
Strain Hardening Behavior ◽  
Polymer Chain Alignment ◽  
Nonlinear Hardening

Polymer nanocomposites—materials in which a polymer matrix is blended with nanoparticles (or fillers)—strengthen under sufficiently large strains. Such strain hardening is critical to their function, especially for materials that bear large cyclic loads such as car tires or bearing sealants. Although the reinforcement (i.e., the increase in the linear elasticity) by the addition of filler particles is phenomenologically understood, considerably less is known about strain hardening (the nonlinear elasticity). Here, we elucidate the molecular origin of strain hardening using uniaxial tensile loading, microspectroscopy of polymer chain alignment, and theory. The strain-hardening behavior and chain alignment are found to depend on the volume fraction, but not on the size of nanofillers. This contrasts with reinforcement, which depends on both volume fraction and size of nanofillers, potentially allowing linear and nonlinear elasticity of nanocomposites to be tuned independently.

Tensile and Cracking Behaviors of Strain-Hardening Cement Composite (SHCC) with Fluosilicate Based Shrinkage-Reducing Agent (SRA)

2014 ◽  
Vol 525 ◽  
pp. 473-477 ◽  
Author(s):  
Seung Ju Han ◽  
Seok Joon Jang ◽  
Zhong Jie Yu ◽  
Hyun Do Yun
Keyword(s):  
Strain Hardening ◽  
Volume Fraction ◽  
Cement Composite ◽  
Tensile Tests ◽  
Reducing Agent ◽  
Direct Tension ◽  
Direct Tension Test ◽  
Rich Mixture ◽  
Direct Tensile ◽  
Shrinkage Reducing Agent

This paper provides the results of direct tensile tests for strain-hardening cement composite (SHCC) to investigate the influence of fluosilicate based shrinkage-reducing agent (SRA) on the tensile and cracking behaviors of SHCC material under direct tension. The specified compressive strength of the SHCC material is 50MPa. The adding ratio of fluosilicate based SRA for SHCC material is 2.5 and 5.0%. Two mixitures of SHCC with 2.2% polyvinyl alcohol (PVA) fibers at the volume fraction were mixed; two mixtures with SRA and one mixture of conventional SHCC material. To evaluate the tensile and cracking behaviors of SHCC materials, two dumbbell-shaped tensile specimens for each mixture were manufactured and tested in direct tension. Test results show that the addition of fluosilicate based SRA improved direct tensile and cracking behaviors of SHCC materials with rich mixture. This phenomenon is noticeable for SHCC with higher volume of SRA.

scholarly journals Influence of fiber size on mechanical properties of strain-hardening fiber-reinforced concrete

2020 ◽  
Vol 14 (3) ◽  
pp. 84-95
Author(s):  
Duy-Liem Nguyen ◽  
Thac-Quang Nguyen ◽  
Huynh-Tan-Tai Nguyen
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Volume Fraction ◽  
Tensile Specimen ◽  
Gauge Length ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Compressive Properties ◽  
Fiber Volume ◽  
Fiber Size

This research deals with the influences of macro, meso and micro steel-smooth fibers on tensile and compressive properties of strain-hardening fiber-reinforced concretes (SFCs). The different sizes, indicated by length/diameter ratio, of steel-smooth fiber added in plain matrix (Pl) were as follows: 30/0.3 for the macro (Ma), 19/0.2 for the meso (Me) and 13/0.2 for the micro fiber (Mi). All SFCs were used the same fiber volume fraction of 1.5%. The compressive specimen was cylinder-shaped with diameter × height of 150 × 200 mm, the tensile specimen was bell-shaped with effective dimensions of 25 × 50 × 100 mm (thickness × width × gauge length). Although the adding fibers in plain matrix of SFCs produced the tensile strain-hardening behaviors accompanied by multiple micro-cracks, the significances in enhancing different mechanical properties of the SFCs were different. Firstly, under both tension and compression, the macro fibers produced the best performance in terms of strength, strain capacity and toughness whereas the micro produced the worst of them. Secondly, the adding fibers in plain matrix produced more favorable influences on tensile properties than compressive properties. Thirdly, the most sensitive parameter was observed to be the tensile toughness. Finally, the correlation between tensile strength and compressive strength of the studied SFCs were also reported. Keywords: aspect ratio; strain-hardening; post-cracking; ductility; fiber size.

Effects of Shrinkage Reducing Admixture (SRA) on the Tensile Behavior of Strain-Hardening Cement Composite (SHCC)

2013 ◽  
Vol 372 ◽  
pp. 203-206
Author(s):  
Seung Ju Han ◽  
Hye Ran Kim ◽  
Hyun Do Yun
Keyword(s):  
Strain Hardening ◽  
Volume Fraction ◽  
Cement Composite ◽  
Tensile Behavior ◽  
Direct Tension ◽  
Air Content ◽  
Shrinkage Reducing Admixture ◽  
Cracking Characteristics ◽  
Shrinkage Reducing Admixtures ◽  
Change Material

This research investigates the influence of shrinkage reducing admixture (SRA) on the tensile behavior of strain-hardening cement composite (SHCC). SHCC materials with specified compressive strength of 50MPa were mixed and tested. All SHCC mixes with different dosage of shrinkage reducing admixtures were reinforced with 2.2 % polyvinyl alcohol (PVA) fibers at the volume fraction. A special SRA, i.e. strontium (Sr)-based SRA, used in this study was based on a phase change material (PCM) that has the ability to absorb or release the hydration heat of cement composite. This paper focuses on the tensile behavior and cracking characteristics of SHCC materials under direct tension. The effect of a special SRA on the fresh properties, such as flow and air content, and hardened properties of SHCC materials was investigated. Test results showed that SRA reduces the air content of SHCC material. The SRA can also improve the tensile strength of SHCC material.

Flexural Toughness of Sprayable Strain-Hardening Cement Composite (SHCC) for Seismic Retrofit of Non-Ductile Reinforced Concrete Frames

2013 ◽  
Vol 658 ◽  
pp. 34-37 ◽  
Author(s):  
Seung Ju Han ◽  
Hyun Do Yun
Keyword(s):  
Reinforced Concrete ◽  
Strain Hardening ◽  
Strong Influence ◽  
Volume Fraction ◽  
Cement Composite ◽  
Flexural Behavior ◽  
Test Results ◽  
Flexural Test ◽  
Concrete Frames ◽  
Flexural Toughness

This experimental study investigates the flexural behavior and toughness of sprayable strain-hardening cement composite (SHCC) developed to retrofit seismically reinforced concrete structures with non-ductile reinforcement details. Three SHCC mixtures with specified compressive strength of 50 MPa are mixed and tested. All SHCC mixes with different dosage and combination of admixtures such as superplasticizer and powder admixture were reinforced with 2.2 % polyvinyl alcohol (PVA) fibers at the volume fraction. This paper focuses on the flexural toughness based on the flexural test results for 100 x 100 x 400 mm prisms. The flexural toughness is evaluated in accordance with ASTM C 1018. The results indicated that less than 2.5 % dosage of hybrid superplasticizer and powder admixtures respectively provides excellent sprayability and flexural behavior of SHCC mixed in this study. A strong influence of hybrid superplasticizer and powder admixture on the flexural toughness of SHCC mixes was observed.

Uniaxial Tensile Experiment on PVA Fiber Reinforced Cementitious Composites

2013 ◽  
Vol 438-439 ◽  
pp. 270-274
Author(s):  
Hai Long Wang ◽  
Guang Yu Peng ◽  
Yue Jing Luo ◽  
Xiao Yan Sun
Keyword(s):  
Volume Fraction ◽  
Ultimate Strain ◽  
Mineral Admixtures ◽  
Uniaxial Tensile ◽  
Cementitious Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Tensile Experiment ◽  
Fiber Reinforced Cementitious Composites ◽  
Uniaxial Tensile Experiment

Engineered cementitious composite (ECC) is a representative of the new generation of high performance fiber reinforced cementitious composites. To reveal the influence of mineral admixtures on the tensile mechanical characteristics of polyvinyl alcohol fiber reinforced engineered cementitious composites (PVA-ECC), the tensile properties of PVA-ECC with replacing cement by a significant amount of fly ash (FA), silica fume (SF) and metakaolin (MK) was experimentally investigated. Uniaxial tensile experiment was carried out using rectangular thin plate with sizes of 400×100×15mm3. Results from uniaxial tensile tests show that these mineral admixtures can improve the properties of PVA-ECC. The composite can achieve an ultimate strain of 2.0%, as well as an ultimate strength of 4.0MPa, with a moderate fiber volume fraction of 2.0%. In addition, the composites with FA, SF and MK show saturated multiple cracking characteristics with crack width at ultimate strain limited to below 175μm.

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