• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.118-121
• /
• 2006

The research reported here is concerned with the effects of the fiber combination condition and water/cement ratio on the mechanical properties of high performance fiber-reinforced cementitious composites(HPFRCC). An experimental investigation of the behavior of steel cords(SC) and SC and Polyethylene(PE) hybrid fiber reinforced cementitious material under compressive and tensile loading is presented. In this experimental research, the tensile and compressive strength and strain capacity of HPFRCC were selected using the cylindrical specimens. The results show that W/C ratio is a significant effect factor on the compressive and tensile performance of HPFRCC. The envelope curve concept applies to hybrid fiber-reinforced cementitious composites in tension just as it does to compressive stress-strain curve of fiber-reinforced cement composites. For practical purposes, the tensile envelope curve may be taken to be the same as the monotonic tensile stress-strain curve.

• Composites Research
• /
• v.19 no.1
• /
• pp.43-48
• /
• 2006

High performance fiber reinforced cement composites have better performances than traditional cement based materials, therefore, have been expected as new construction applications such as the materials for construction & bridge structure, repair and rehabilitation applications, anti-collapse applications, anti-noise applications etc. However, they have lots of the problems such as material design, fabrication method and structural analysis. Also, the most serious problems of High performance fiber reinforced cement composites have been expensive initial cost, lack of long-term exposure data. As a result, it is needed that the efforts for lowering the initial cost and accumulation of long-term exposure. There has been hardly assessment results of life cycle cost for HPFRCC in construction field, but some papers showed that total life cycle cost could be profitable if the initial cost could be reduced.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.05a
• /
• pp.87-90
• /
• 2005

An experimental investigation on the strength and behaviour of reinforced concrete columns using high performance fiber reinforced cement composites has been carried out. The columns were subjected to monotonic axial compression until failure. The variables in this study are the combination ratio of steel cord(SC) and Polyethylene (PE), and the volumetric ratio of transverse reinforcement Test results showed that the fibers, when used in a hybrid form, could result in superior composite performance compared to their individual fiber reinforced cement composites.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.11a
• /
• pp.631-634
• /
• 2004

An experimental investigation on the strength and behaviour of reinforced concrete columns using high performance fiber reinforced cement composites has been carried out. The columns were subjected to monotonic axial compression until failure. The variables in this study are the combination ratio of steel cord(SCI) and polypropylene(PP), and the volumetric ratio of transverse reinforcement Test results showed that the fibers, when used in a hybrid form, could result in superior composite performance compared to their individual fiber reinforced cement composites.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.05a
• /
• pp.275-278
• /
• 2005

High performance fiber reinforced cement composites(HPFRCCs) is a class of high ductile fiber reinforced cementitious composites developed for applications in the sensitive construction industry. HPFRCCs has undergone major evolution in both materials development and the range of emerging applications. This paper is to evaluate structural strengthening performance of LRCF(Lightly reinforced concrete frame) using the HPFRCCs. The experimental results, as expected, show that the crack load, yield load, and limited load are superior for specimen with HPFRCCs infill wall due to crosslink effect of fibers in concrete.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.4
• /
• pp.92-100
• /
• 2015

The aim of this study is to evaluate the fracture characteristics of ductile fiber reinforced cement based composites with 1.5 volume ratio of polyvinyl alcohol and steel fiber by high velocity impact of steel projectile. We used gunpowder impact facility to evaluate the fracture characteristics of ductile fiber reinforced cement based composites by collision of steel projectile, and the impact velocity was from about 150 to 1,000m/s. The results of evaluation on the fracture characteristics of ductile fiber reinforced cement based composites were penetration grade, which is the kinetic energy more than three times of no-fiber reinforced specimen (Plain). In addition, ductile fiber reinforced cement based composites did not occurred critical damage other than the debris. In the case of mass loss, Plain specimen was proportional to kinetic energy of steel projectile, while ductile fiber reinforced cement based composites was not significantly affected by kinetic energy of steel projectile. In particular, this tendency had a close relationship with the fracture characteristics of back side of specimens, and the scabbing inhibiting efficiency of PVA specimen was higher than S specimen. In the results of verifying relationship between front and back side calculated by local damage, scabbing occurred at the region close to the back side in the ductile fiber reinforced cement based composites unlike Plain specimen. Thus, in this study, we examined principal fracture behaviors of ductile fiber reinforced cement based composites under collision of steel projectile, and verified that impact resistance performance was improved as compared to Plain specimen.

• Journal of the Korea Concrete Institute
• /
• v.27 no.2
• /
• pp.157-167
• /
• 2015

Cement composites subjected to high-velocity projectile shows local failure and it can be suppressed by improvement of flexural toughness with reinforcement of fiber. Therefore, researches on impact resistance performance of cement composites are in progress and a number of types of fiber reinforcement are being developed. Since bonding properties of fiber with matrix, specific surface area and numbers of fiber are different by fiber reinforcement type, mechanical properties of fiber reinforced cement composites and improvement of impact resistance performance need to be considered. In this study, improvement of flexural toughness and failure reduction effect by impact of high-velocity projectile have been evaluated according to fiber type by mixing steel fiber, polyamide, nylon and polyethylene which are have different shape and mechanical properties. As results, flexural toughness was improved by redistribution of stress and crack prevention with bridge effect of reinforced fibers, and scabbing by high-velocity impact was suppressed. Since it is possible to decrease scabbing limit thickness from impact energy, thickness can be thinner when it is applied to protection. Scabbing of steel fiber reinforced cement composites was occurred and it was observed that desquamation of partial fragment was suppressed by adhesion between fiber and matrix. Scabbing by high-velocity impact of synthetic fiber reinforced cement composites was decreased by microcrack, impact wave neutralization and energy dispersion with a large number of fibers.

• International Journal of Concrete Structures and Materials
• /
• v.3 no.1
• /
• pp.71-77
• /
• 2009

A theoretical model of multiple cracking failure mechanism is proposed herein for fiber reinforced high performance Cementitious composites. By introducing partial debonding energy dissipation on non-first cracking plane and fiber reinforcing parameter, the failure mechanism model of multiple cracking is established based on the equilibrium assumption of total energy dissipation on the first crack plane and non-first cracking plane. Based on the assumption of the first crack to be the final failure crack, energy dissipation terms including complete debonding energy, partial debonding energy, strain energy of steel fiber, frictional energy, and matrix fracture energy have been modified and simplified. By comparing multiple cracking number and energy dissipations with experiment results of the reference's data, it indicates that this model can describe the multiple cracking behavior of fiber reinforced high performance cementitious composites and the influence of the partial debonding term on energy dissipation is significant. The model proposed may lay a foundation for the predictions of the first cracking capacity and post cracking capacity of fiber reinforced high performance cementitious composites and also can be a reference for optimal mixture for construction cost.

• International Journal of Concrete Structures and Materials
• /
• v.3 no.2
• /
• pp.119-126
• /
• 2009

This paper provides a brief summary of the performance of an innovative slip hardening twisted steel fiber in comparison with other fibers including straight steel smooth fiber, high strength steel hooked fiber, SPECTRA (high molecular weight polyethylene) fiber and PVA fiber. First the pull-out of a single fiber is compared under static loading conditions, and slip rate-sensitivity is evaluated. The unique large slip capacity of T-fiber during pullout is based on its untwisting fiber pullout mechanism, which leads to high equivalent bond strength and composites with high ductility. Due to this large slip capacity a smaller amount of T-fibers is needed to obtain strain hardening tensile behavior of fiber reinforced cementitious composites. Second, the performance of different composites using T-fibers and other fibers subjected to tensile and flexural loadings is described and compared. Third, strain rate effect on the behavior of composites reinforced with different types and amounts of fibers is presented to clarify the potential application of HPFRCC for seismic, impact and blast loadings.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2017.05a
• /
• pp.214-215
• /
• 2017

Extreme loads such as impact and explosion have higher strain rate than static loading condition. Therefore, it is necessary to evaluate mechanical properties at high strain rate in order to apply fiber reinforced cement composites to ensure safety performance against impact and explosion. In this study, the compressive properties of fiber reinforced cement composites by strain rate were evaluated.