Influence of Shrinkage Compensation in Cement Matrix on the Tension Stiffening of Reinforced Strain-Hardening Cement Composite (SHCC) Tension Ties

This paper investigates the interaction of structural deformed bar reinforcement and strain hardening cement composite (SHCC). The SHCC shows excellent mechanical properties such as multiple cracks and strain-hardening. Generally, SHCC material consists of cement, silica sand and fibers and is rich mixture without aggregate. Rich mixture leads to much shrinkage strain of SHCC material. In this research, the replacement of a part of cement by expansive admixture (EXA) is considered as an alternative to compensate the shrinkage strain of SHCC material. This paper presents the experimental results of tests on tension stiffening and cracking behavior of reinforced conventional and shrinkage-compensating SHCC ties in monotonic and cyclic tension. Each tie specimen had a square cross-section dimension of 100 x 100mm and length of 1,500mm. A 16mm diameter deformed bar was embedded centrally and mixed with 1.5% hybrid fibers composed of Polyethylene(PE) and Steel core(SC). The test results indicated that the shrinkage compensation of cement matrix in SHCC improve the tension stiffening and cracking behavior of reinforced SHCC ties in monotonic and cyclic tension loading.

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Tension Stiffening and Cracking Behavior of Ultra High Strength Strain-Hardening Cement Composite (UHS-SHCC) Ties in Monotonic and Cyclic Tension

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.3982 ◽

2012 ◽

Vol 204-208 ◽

pp. 3982-3985

Author(s):

Young Jae Song ◽

Hyun Do Yun

Keyword(s):

Strain Hardening ◽

High Strength ◽

High Volume ◽

Cement Composite ◽

Initial Crack ◽

Conventional Concrete ◽

Tension Stiffening ◽

Cracking Behavior ◽

Cyclic Tension ◽

Reinforced Cement

This study investigates the tensile response of reinforced ultra high strength strain- hardening cement composite (UHS-SHCC) ties in directly monotonic and cyclic tension. The UHS-SHCC exhibits valuable material properties such as high compressive strength, tensile strain-hardening and ductility. However, UHS-SHCC requires high volume of cement, which leads to more shrinkage than conventional concrete. Authors have considered replacing a part of cement by the expansive admixture (EXA) for compensating the shrinkage of UHS-SHCC. Specifically, this paper explores the structural application of a shrinkage-compensating UHS-SHCC to improve tension stiffening in structural members. The cement composite type and EXA replacement were taken as experimental parameters. All specimens had a square cross-section dimension of 100 x 100mm and length of 1,500mm. The test results indicate that the shrinkage compensating UHS-SHCC is very effective to improve tension stiffening behavior and initial crack load of reinforced cement composite ties.

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The Effect of Shrinkage-Compensation on the Performance of Strain-Hardening Cement Composite (SHCC)

Sustainability ◽

10.3390/su11051453 ◽

2019 ◽

Vol 11 (5) ◽

pp. 1453 ◽

Cited By ~ 2

Author(s):

Seok-Joon Jang ◽

Ji-Hyeon Kim ◽

Sun-Woo Kim ◽

Wan-Shin Park ◽

Hyun-Do Yun

Keyword(s):

Compressive Strength ◽

Strain Hardening ◽

Extreme Environments ◽

Cement Composite ◽

Civil Infrastructure ◽

Conventional Concrete ◽

Calcium Sulfoaluminate ◽

Rich Mixture ◽

Shrinkage Compensation ◽

Direct Tensile

This study investigated the effects of shrinkage compensation on the tensile and cracking responses of strain-hardening cement composite (SHCC) by adding calcium sulfoaluminate (CSA)-based expansive additive (EXA) to the mixture. Such responses are closely related to the durability of concrete structures, of dumbbell-shaped SHCC specimens, and reinforced SHCC ties. For this study, two SHCC mixtures and a conventional concrete mixture with a specific compressive strength value of 30 MPa were prepared and measured in terms of shrinkage history, compressive strength, flexural strength, and direct tensile strength. The test results show that the mechanical properties of shrinkage-compensated SHCC with 10% CSA-based EXA are superior to those of conventional SHCC and concrete mixtures. Also, reinforced tension ties with shrinkage-compensated SHCC exhibited the best multiple cracking and tension-stiffening behavior among the three types of tension ties tested. The results show that shrinkage compensation using CSA-based EXA in SHCC with rich mixture is effective for resisting crack damage. Shrinkage-compensated SHCC may be used for civil infrastructure facilities that require high levels of durability and are exposed to extreme environments.

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Tension-Stiffening and Cracking Behavior of 100 MPa Shrinkage-Compensated Ultra High-Strength Strain-Hardening Cement Composite (UHS-SHCC) Ties

Journal of the Korea Concrete Institute ◽

10.4334/jkci.2013.25.4.371 ◽

2013 ◽

Vol 25 (4) ◽

pp. 371-379 ◽

Cited By ~ 1

Author(s):

Young-Jae Song ◽

Hyun-Do Yun

Keyword(s):

Strain Hardening ◽

High Strength ◽

Cement Composite ◽

Tension Stiffening ◽

Cracking Behavior

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Feasibility of Reduced Lap-Spliced Length in Polyethylene Fiber-Reinforced Strain-Hardening Cementitious Composite

Advances in Materials Science and Engineering ◽

10.1155/2018/1967936 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10

Author(s):

Wonchang Choi ◽

Seok-Joon Jang ◽

Hyun-Do Yun

Keyword(s):

Strain Hardening ◽

Cement Composite ◽

Cementitious Composite ◽

Fiber Reinforced ◽

Interfacial Behavior ◽

Reinforcing Bars ◽

Cracking Behavior ◽

Lap Splice ◽

Cyclic Tension ◽

Polyethylene Fiber

This research investigates the interfacial behavior between polyethylene (PE) fiber-reinforced strain-hardening cement composite (PE-SHCC) and reinforcing bars that are spliced in the tension region to determine feasibility of reduced lap-spliced length in PE-SHCC. Twenty test specimens were subjected to monotonic and cyclic tension loads. The variables include the replacement levels of an expansive admixture (0% and 10%), the compressive strength of the SHCC mixtures (40 MPa and 80 MPa), and the lap-spliced length in the tension region (40% and 60% of the splice length recommended by ACI 318). The PE-SHCC mixture contains polyethylene fiber to enhance the tensile strength, control the widths of the cracks, and increase the bond strength of the lap splice reinforcement and the calcium sulfo-aluminate- (CSA-) based expansive admixture to improve the tension-related performance in the lap splice zone. The results have led to the conclusion that SHCC mixtures can be used effectively to reduce the development length of lap splice reinforcement up to 60% of the splice length that is recommended by ACI 318. The addition of the calcium sulfo-aluminate-based expansive admixture in the SHCC mixtures improved the initial performance and mitigated the cracking behavior in the lap splice region.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.525.473 ◽

2014 ◽

Vol 525 ◽

pp. 473-477 ◽

Cited By ~ 1

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.

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

Advances in Civil Engineering ◽

10.1155/2018/6727516 ◽

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.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.372.219 ◽

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.

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