• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.401-402
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• 2010

This research initially suggest flexural toughness density as a key parameter describing energy absorption capacity of High Performance Fiber Reinforced Cementitious Composites [HPFRCC] regardless of the size of specimen. Two types of high strength steel fibers, Hooked and Twisted fiber, were used in two types of flexural specimen ($100{\times}100{\times}350mm^3$ and $150{\times}150{\times}500mm^3$) to estimate and validate the flexural toughness density.

• International Journal of Concrete Structures and Materials
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• v.18 no.3E
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• pp.207-211
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• 2006

This paper presents an experimental study on the repair performance of sprayed engineered cementitious composites(ECC) serving as a repair material. Sprayable ECC, which exhibit tensile strain-hardening behavior in the hardened state and maintain sprayable properties in the fresh state, have been developed by using a parallel control of micromechanical design and rheological process design. The effectiveness of sprayable ECC in providing durable repaired structures was assessed by spraying the ECC and testing them for the assessment. The experimental results revealed that, when sprayed ECC were used as a repair material, both load carrying capacity and ductility represented by the deformation capacity at peak load of the repaired flexural beams were obviously increased compared to those of commercial prepackaged mortar(PM) repaired beams. The significant enhancement in the energy absorption capacity and tight crack width control of the ECC repair system treated with wet-mix spraying process suggests that sprayed ECC can be effective in extending the service life of rehabilitated infrastructures.

• Structural Engineering and Mechanics
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• v.52 no.5
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• pp.857-873
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• 2014

Structural behaviors of a sustainable hybrid column with the ultra high performance cementitious composites (UHPCC) permanent form under compression and flexure were studied. Critical state and failure stage characters are analyzed for large and small eccentricity cases. A simplified theoretical model is proposed for engineering designs and unified formulas for loading capacity of the hybrid column under compression and flexure loads are derived, including axial force and moment. Non-linear numerical analysis is carried out to verify the theoretical predictions. The theoretical predictions agree well with the numerical results which are verified by the short hybrid column tests recursively. Compared with the traditional reinforced concrete (RC) column, the loading capacity of the sustainable hybrid column is improved significantly due to UHPCC confinements.

• Structural Engineering and Mechanics
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• v.55 no.5
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• pp.931-951
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• 2015

To improve the durability and service life of reinforced concrete column such as bridge piers, an advanced composite column made of Ultra High Performance Cementitious Composites (UHPCC) permanent form is proposed. Based on elasticity plasticity theory, axial compression behavior of the composite column was studied theoretically. The first circumferential cracking load and ultimate limit loading capacity are derived for the composite column. Short composite column compression tests and numerical simulations using FEM method were carried out to justify the theoretical formula. The effects of UHPCC tube thickness on the axial compression behavior were studied. Using the established theoretical model and numerical simulation, the large dimension composite columns are calculated and analyzed with different UHPCC tube thickness. These studies may provide a reference for advanced composite column design and application.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.577-580
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• 2004

Recently, DFRCCs (Ductile Fiber Reinforced Cementitious Composites), materials with remarkable ductility when compared to ordinary fiber-reinforced concrete (FRC), have been developed and studied actively in the US, Japan, and many European countries. The transformation of failure behavior from brittle to ductile is achieved by incorporating with fracture mechanics concept especially micro-mechanical models approach of cementitious composite materials in manufacturing ordinary fiber-reinforced composites. The purpose of this study is to accurately understand the shear behavior of DFRCC repaired RC beams. Using a four-point bending test, the shear strengths and shear stress-deflection relations of DFRCC repaired RC specimens are obtained. The results show that DFRCC can be effectively used for repairing materials for concrete structures.

• Earthquakes and Structures
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• v.26 no.4
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• pp.269-283
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• 2024

When a reinforced concrete (RC) structure is exposed to a corrosive environment for an extended period of time, the material qualities deteriorate, resulting in a loss in seismic performance. Engineered Cementitious Composites (ECC) have been used to reinforce the corroded RC structure, which can achieve reinforcement effectiveness for a small change in cross-section size. In this work, finite element models of unjacketed RC pier and ECC jacketed pier were established and verified by experimental tests, with the buckling effect of longitudinal reinforcement considered. Compared with the unjacketed pier, the displacement of the pier top of the ECC jacketed pier was reduced by about 9.52% under earthquake action. In the case of moderate and major earthquakes, the probability of exceedance of ECC jacketed pier is significantly reduced. For the case of rare earthquake loading, with the ECC jacket, the e of the pier experiencing serious damage and complete damage states is reduced by 10.29% and 29.78%, respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.5
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• pp.615-627
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• 2024

This study presents fundamental research data on the application and utility of biochar in Engineered Cementitious Composites (ECC) for carbon sequestration. The study experimentally measures and compares the compressive strength, tensile strength, and flexural strength of high-toughness biochar-incorporated ECC (BE) and biochar-incorporated mortar (BM) with varying levels of biochar replacement. This study aims to compare BM and BE. BM shows an increase in mechanical properties at a biochar content of 1 %. BE shows an increase in mechanical properties at a biochar content of 2 %. The reason for the increase is that biochar particles fill the voids between the binder materials, acting as a filler. This helps form a denser structure. These findings suggest that incorporating biochar into mortar and ECC can enhance their mechanical properties at optimal biochar contents.

• Magazine of the Korea Concrete Institute
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• v.18 no.1 s.90
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• pp.28-35
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• 2006

• Magazine of the Korea Concrete Institute
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• v.16 no.5 s.82
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• pp.64-72
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• 2004

• Magazine of the Korea Concrete Institute
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• v.18 no.3 s.92
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• pp.82-86
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• 2006