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

2019 ◽  
Vol 11 (5) ◽  
pp. 1453 ◽  
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.

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.

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

2012 ◽  
Vol 204-208 ◽  
pp. 3660-3663
Author(s):  
Hyun Do Yun ◽  
Su Chang Wang ◽  
Chang Gun Cho
Keyword(s):  
Strain Hardening ◽  
Shrinkage Strain ◽  
Cement Composite ◽  
Cement Matrix ◽  
Tension Stiffening ◽  
Cracking Behavior ◽  
Rich Mixture ◽  
Cyclic Tension ◽  
Shrinkage Compensation ◽  
Deformed Bar

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.

Advanced concretes for high temperature applications

2019 ◽  
Author(s):  
Alok A. Deshpande ◽  
Dhanendra Kumar ◽  
Ravi Ranade ◽  
Andrew S. Whittaker
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Strain Hardening ◽  
Modulus Of Rupture ◽  
Direct Tension ◽  
Conventional Concrete ◽  
Normal Strength ◽  
Temperature Applications

<p>The mechanical properties of concrete deteriorate at high temperatures. Strain-hardening cementitious composites (SHCC) are a special class of fiber-reinforced concretes that exhibit strain-hardening behavior in direct tension. The mechanical behavior of a SHCC made using polyvinyl alcohol (PVA) fibers is characterized after exposure to temperatures up to 800°C. The effects of temperature on compressive strength, splitting tensile strength and modulus of rupture are reported. For comparison, a normal strength conventional concrete of similar compressive strength to the SHCC was heated and tested in the same conditions as the SHCC. The normalized tensile strength of SHCC at room temperature, and after exposure to high temperature, is significantly greater than the value for conventional concrete. The PVA fibers provide crack-bridging capacity up to about 200°C (melting point of PVA fibers is 230°C), leading to improved tensile behavior. At greater temperatures, the fibers melt, creating pathways for steam to escape, reducing micro-cracking and significantly improving mechanical behavior with respect to conventional concrete. SHCC is a robust alternative to conventional concrete for high temperature applications.</p>

scholarly journals Effect of Expansive Admixtures on the Shrinkage and Mechanical Properties of High-Performance Fiber-Reinforced Cement Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Won-Chang Choi ◽  
Hyun-Do Yun
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Shrinkage Strain ◽  
Cement Composites ◽  
Fiber Reinforced ◽  
Calcium Sulfoaluminate ◽  
High Performance Fiber ◽  
Reinforced Cement ◽  
Shrinkage Compensation ◽  
Direct Tensile

High-performance fiber-reinforced cement composites (HPFRCCs) are characterized by strain-hardening and multiple cracking during the inelastic deformation process, but they also develop high shrinkage strain. This study investigates the effects of replacing Portland cement with calcium sulfoaluminate-based expansive admixtures (CSA EXAs) to compensate for the shrinkage and associated mechanical behavior of HPFRCCs. Two types of CSA EXA (CSA-K and CSA-J), each with a different chemical composition, are used in this study. Various replacement ratios (0%, 8%, 10%, 12%, and 14% by weight of cement) of CSA EXA are considered for the design of HPFRCC mixtures reinforced with 1.5% polyethylene (PE) fibers by volume. Mechanical properties, such as shrinkage compensation, compressive strength, flexural strength, and direct tensile strength, of the HPFRCC mixtures are examined. Also, crack width and development are investigated to determine the effects of the EXAs on the performance of the HPFRCC mixtures, and a performance index is used to quantify the performance of mixture. The results indicate that replacements of 10% CSA-K (Type 1) and 8% CSA-J (Type 2) considerably enhance the mechanical properties and reduce shrinkage of HPFRCCs.

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.

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

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.

Engineered/strain-hardening cementitious composites (ECC/SHCC) with a compressive strength over 210 MPa

2021 ◽  
pp. 100775
Author(s):  
Bo-Tao Huang ◽  
Ke-Fan Weng ◽  
Ji-Xiang Zhu ◽  
Yu Xiang ◽  
Jian-Guo Dai ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Strain Hardening ◽  
Cementitious Composites ◽  
Engineered Strain

scholarly journals Properties of Calcium Sulfoaluminate Cement Mortar Modified by Hydroxyethyl Methyl Celluloses with Different Degrees of Substitution

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2136
Author(s):  
Shaokang Zhang ◽  
Ru Wang ◽  
Linglin Xu ◽  
Andreas Hecker ◽  
Horst-Michael Ludwig ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Bond Strength ◽  
Cement Mortar ◽  
Retention Rate ◽  
Methyl Cellulose ◽  
Tensile Bond Strength ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Cement Mortars

This paper studies the influence of hydroxyethyl methyl cellulose (HEMC) on the properties of calcium sulfoaluminate (CSA) cement mortar. In order to explore the applicability of different HEMCs in CSA cement mortars, HEMCs with higher and lower molar substitution (MS)/degree of substitution (DS) and polyacrylamide (PAAm) modification were used. At the same time, two kinds of CSA cements with different contents of ye’elimite were selected. Properties of cement mortar in fresh and hardened states were investigated, including the fluidity, consistency and water-retention rate of fresh mortar and the compressive strength, flexural strength, tensile bond strength and dry shrinkage rate of hardened mortar. The porosity and pore size distribution were also analyzed by mercury intrusion porosimetry (MIP). Results show that HEMCs improve the fresh state properties and tensile bond strength of both types of CSA cement mortars. However, the compressive strength of CSA cement mortars is greatly decreased by the addition of HEMCs, and the flexural strength is decreased slightly. The MIP measurement shows that HEMCs increase the amount of micron-level pores and the porosity. The HEMCs with different MS/DS have different effects on the improvement of tensile bond strength in different CSA cement mortars. PAAm modification can improve the tensile bond strength of HEMC-modified CSA cement mortar.

scholarly journals Effect of Recycled Coarse Aggregate and Bagasse Ash on Two-Stage Concrete

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 556
Author(s):  
Muhammad Faisal Javed ◽  
Afaq Ahmad Durrani ◽  
Sardar Kashif Ur Rehman ◽  
Fahid Aslam ◽  
Hisham Alabduljabbar ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Construction Material ◽  
Strength Reduction ◽  
Recycled Aggregate ◽  
Two Stage ◽  
Conventional Concrete ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates

Numerous research studies have been conducted to improve the weak properties of recycled aggregate as a construction material over the last few decades. In two-stage concrete (TSC), coarse aggregates are placed in formwork, and then grout is injected with high pressure to fill up the voids between the coarse aggregates. In this experimental research, TSC was made with 100% recycled coarse aggregate (RCA). Ten percent and twenty percent bagasse ash was used as a fractional substitution of cement along with the RCA. Conventional concrete with 100% natural coarse aggregate (NCA) and 100% RCA was made to determine compressive strength only. Compressive strength reduction in the TSC was 14.36% when 100% RCA was used. Tensile strength in the TSC decreased when 100% RCA was used. The increase in compressive strength was 8.47% when 20% bagasse ash was used compared to the TSC mix that had 100% RCA. The compressive strength of the TSC at 250 °C was also determined to find the reduction in strength at high temperature. Moreover, the compressive and tensile strength of the TSC that had RCA was improved by the addition of bagasse ash.

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