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.

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.

Damage Tolerance of Reinforced Concrete (RC) Beams with a Layer of PE Fiber Reinforced Strain-Hardening Cement Composite (PE-SHCC)

2013 ◽  
Vol 372 ◽  
pp. 219-222
Author(s):  
Yeon Jun Yun ◽  
Seok Joon Jang ◽  
Hyun Do Yun
Keyword(s):  
Reinforced Concrete ◽  
Strain Hardening ◽  
Volume Fraction ◽  
Cement Composite ◽  
Rc Beam ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Cracking Behavior ◽  
Flexural Performance ◽  
Strength And Ductility

This work evaluated the applicability of polyethylene (PE) fiber reinforced strain-hardening cement composite (PE-SHCC) layer at the bottom of reinforced concrete (RC) beams to improve the flexural performance and cracking behavior. PE-SHCC material with specific compressive strength of 70MPa was reinforced with 1.5% PE fibers at the volume fraction. Four RC beams with cross-section of 130 x 170mm and length of 1,460mm were made and tested under four-point monotonic loading. Three beams were layered with PE-SHCC material and one whole RC beam was a control specimen for comparison. Principal variable is the thickness of PE-SHCC layer; 20, 40 and 60mm that are equivalent to 11, 23 and 35% of beams depth. Experimental results indicated that the addition of PE-SHCC layer enhanced the crack-damage mitigation of RC beams and improve the structural behavior, such as strength and ductility, of RC beams.

Structural Behaviors of Non-Ductile Reinforced Concrete Frames with Engineered Cement Composite (ECC) Wing Wall Elements

2014 ◽  
Vol 597 ◽  
pp. 328-331
Author(s):  
Dae Hyun Kang ◽  
Won Gyun Lim ◽  
Hye Ran Kim ◽  
Mi Hwa Lee ◽  
Hyun Do Yun
Keyword(s):  
Reinforced Concrete ◽  
Cement Composite ◽  
Rc Frame ◽  
Test Results ◽  
Seismic Strengthening ◽  
Concrete Frames ◽  
Lower Beam ◽  
Pva Fiber ◽  
Structural Behaviors ◽  
Strengthening Method

In this paper, an experimental investigation was carried out to evaluate the application of engineered cement composite (ECC) wing wall elements for seismic strengthening of reinforced concrete (RC) buildings with non-ductile reinforcement details. The ECC is mixed with cement, silica fume, fly ash and polyvinyl alcohol (PVA) fiber. The ECC wing wall elements were fitted on three side of RC frame; upper beam, lower beam and column. Two specimens, non-ductile RC bare frame and RC frame strengthened with ECC wing wall, were made for this study. These specimens were made as a third scale for this study. The specimens were loaded through 1,000 kN actuator that consists of two cycles at a displacement level. The test results showed that the seismic strengthening method of ECC wing wall elements had a significant effect to improve seismic performance of non-ductile RC bare frame. As a result, the application of ECC wing wall elements in non-ductile RC bare frame may be effective alternative to seismic retrofit of non-ductile buildings.

scholarly journals Flexural Behavior of Extruded DFRCC Panel and Reinforced Concrete Composite Slab

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Chang-Geun Cho ◽  
Bang Yeon Lee ◽  
Yun Yong Kim ◽  
Byung-Chan Han ◽  
Seung-Jung Lee
Keyword(s):  
Reinforced Concrete ◽  
Cement Composite ◽  
Extrusion Process ◽  
Flexural Behavior ◽  
Composite Slab ◽  
Flexural Performance ◽  
Cracking Control ◽  
Rc Slab ◽  
Reinforced Cement ◽  
Deformation Hardening

This paper presents a new reinforced concrete (RC) composite slab system by applying an extruded Ductile Fiber Reinforced Cement Composite (DFRCC) panel. In the proposed composite slab system, the DFRCC panel, which has ribs to allow for complete composite action, is manufactured by extrusion process; then, the longitudinal and transverse reinforcements, both at the bottom and the top, are placed, and finally the topping concrete is placed. In order to investigate the flexural behavior of the proposed composite slab system, a series of bending tests was performed. From the test results, it was found that the extruded DFRCC panel has good deformation-hardening behavior under flexural loading conditions and that the developed composite slab system, applied with an extruded DFRCC panel, exhibits higher flexural performance compared to conventional RC slab system in terms of the stiffness, load-bearing capacity, ductility, and cracking control.

scholarly journals Flexural Behavior of Reinforced Concrete Beams Reinforced with 3D-Textile Composite Fiber

2020 ◽  
Vol 26 (7) ◽  
pp. 127-144
Author(s):  
Mays R. Abdulghani ◽  
Dr. Ahmed S. Ali
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Main Idea ◽  
Composite Fiber ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Textile Fiber ◽  
Textile Composite

Normal concrete is weak against tensile strength, has low ductility, and also insignificant resistance to cracking. The addition of diverse types of fibers at specific proportions can enhance the mechanical properties as well as the durability of concrete. Discrete fiber commonly used, has many disadvantages such as balling the fiber, randomly distribution, and limitation of the Vf ratio used. Based on this vision, a new technic was discovered enhancing concrete by textile-fiber to avoid all the problems mentioned above. The main idea of this paper is the investigation of the mechanical properties of SCC, and SCM that cast with 3D AR-glass fabric having two different thicknesses (6, 10 mm), and different layers (1,2 layers). As well as micro-steel fiber with 1.25% volume fraction was used. Sixteen rectangular reinforced concrete beam specimens have been tested to study the behavior of their flexural strength. The results concluded that utilizing 3D-TFs with mortar mixture gave significantly higher enhancement for the load-carrying capacity than the concrete mixture. The utilization of 3D-TFs and micro-steel fiber together in the SCM mix gave better results. The stiffness of the specimens was improved with increasing the thickness and the number of textile fiber layers.

scholarly journals Flexure Performance of Externally Bonded CFRP Plates-Strengthened Reinforced Concrete Members

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xin Yuan ◽  
Chaoyu Zhu ◽  
Wei Zheng ◽  
Jiangbei Hu ◽  
Baijian Tang
Keyword(s):  
Failure Modes ◽  
Calculation Model ◽  
Flexural Behavior ◽  
Test Results ◽  
Flexural Test ◽  
Concrete Members ◽  
Cfrp Plate ◽  
Matlab Program ◽  
Externally Bonded ◽  
The Relationship

This paper investigates the flexural behavior of CFRP plate-strengthened concrete structures. Specimens of the CFRP plate-reinforced beam were designed and tested by the four-point flexural test. The load-deflection relationship, failure modes, and crack propagation were analyzed. The results showed that the postcracking stiffness and bearing capacity of the test beams can be improved by the additional anchoring measures for CFRP strengthening. The relationship between flexural moment and curvature was analyzed by introducing a MATLAB program. The calculation model between curvature, flexural moment, and stiffness was derived for the CFRP plate-strengthened structure. The recommended calculation model was applied in the analysis of deflection, and the theoretical values were compared with the test results.

Influence of Fiber Volume Fraction and Aggregate Size on Flexural Behavior of High Strength Steel Fiber-Reinforced Concrete (SFRC)

2013 ◽  
Vol 372 ◽  
pp. 223-226 ◽  
Author(s):  
Seok Joon Jang ◽  
Yeon Jun Yun ◽  
Hyun Do Yun
Keyword(s):  
Reinforced Concrete ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Aggregate Size ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Flexural Behavior ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Volume

The effects of aggregate size and fiber volume fraction on the flexural behavior of 70MPa high strength steel fiber-reinforced concrete (SFRC) were investigated in this work. Test variables consist of fiber volume fraction (0, 1 and 2 %) and maximum aggregate size (8, 13 and 20 mm). The prism for flexural test was 100 x 100 x 400 mm and was tested under four points loading. Flexural toughness index was measured using ASTM C 1018 procedure. Test results indicated that the addition of steel fiber to 70MPa high strength concrete improves flexural and post-cracking behaviors. This phenomenon is remarkable for SFRC mixture with higher fiber content and smaller aggregate size. Also, the flexural toughness of high strength SFRC depends primarily on fiber content. The maximum aggregate sizes were secondary in importance.

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).

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 Flexural Behavior of Bamboo Reinforced Concrete Beam with Steel Stirrups

2019 ◽  
Vol 8 (4S2) ◽  
pp. 97-99
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Flexural Behavior ◽  
Test Results ◽  
Steel Reinforced Concrete ◽  
Beam Design ◽  
Materials Used ◽  
Bamboo Reinforcement

The flexural behavior of concrete beams reinforced with bamboo was studied experimentally. Bamboo was used as the main reinforcement with different bonding materials in place of steel. A nominal mix of M20 grade concrete was adopted for the beam design. The Bamboo surface was treated with common binding materials like Araldite and Bitumen. Araldite and Bitumen are good binding materials used to connect materials like steel, carbon and many different materials. Two specimens were casted with bitumen coating, two specimens were coated with araldite, two specimens were casted without any binder coating and a specimen was casted using normal steel reinforcement. Beams were casted with bamboo reinforcement and cured for 28 days. Deflection and flexural behavior of the beams were monitored. The test results imply that araldite coating in concrete beams with bamboo reinforcement increased the flexural strength to that of bamboo reinforced concrete using bitumen which is lesser strength to that of steel reinforced concrete beam.

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