Sung‐Gul Hong

One of the primary concerns about the design aspects is that how to deal with the shear reinforcement in the ultra-high performance fiber reinforced concrete (UHPFRC) beam. This study aims to investigate the shear behavior of UHPFRC rectangular cross sectional beams with fiber volume fraction of 1.5 % considering a spacing of shear reinforcement. Shear tests for simply supported UHPFRC beams were performed. Test results showed that the steel fibers substantially improved of the shear resistance

For optimum production of ultra-high performance concrete (UHPC), the material and microstructural properties of UHPC cured under various heat treatment (HT) conditions are studied. The effects of HT temperature and duration on the hydration reaction, microstructure, and mechanical properties of UHPC are investigated. Increasing HT temperature accelerates both cement hydration and pozzolanic reaction, but the latter is more significantly affected. This accelerated pozzolanic reaction in UHPC cle

The effects of incorporating carbon nanotubes (CNTs) into ultra-high performance concrete (UHPC), thereby forming UHPC/CNT composites, were investigated in terms of electrical curing efficiency, mechanical properties, and crack sensing capability. The addition of CNTs significantly decreased the electrical resistivity of the UHPC, allowing effective electrical curing at low voltage; improved mechanical properties through bridging, pore filling, and calcium-silicate-hydrate (C-S-H) stiffening eff

The objective of this study is to develop and characterize kaolinite clay-based structural mortar. The pozzolanic reaction induced from two mineral additives, i.e., calcium hydroxide and silica fume (SF), and the physical filling effect from SF, were found to be effective on the enhancement of structural properties. Based on several preliminary experiments, 7:3 ratio of kaolinite clay/calcium hydroxide was selected as a basic binder. Then, the amount of SF was chosen as 0%, 7.5%, and 15% of the

This study aimed at investigating the effects of ozone treatment on the dispersion of carbon nanotubes (CNTs) in aqueous solution and the resulting influence on the material properties of ultra-high performance concrete (UHPC). The CNT suspension was fabricated by the ozone treatment and used to produce UHPC/CNT composites. Using spatially-resolved small angle X-ray scattering, the degree of dispersion of CNTs in UHPC matrix was quantitatively evaluated. It was confirmed that the ozone treatment

This paper presents the structural performance of jacketed concrete columns subjected to cyclic lateral loading using ultrahigh-performance fiber-reinforced concrete (UHPFRC) with various advantages as construction materials of high strength and durability with self-compacting. The UHPFRC jacketing with/without textile reinforcement for concrete columns for the seismic retrofitting demonstrates its strengthening efficiency and reduction of jacket thickness through the experimental program in thi

This study aims to elucidate the effect of carbon nanotube (CNT) concentrations on the mechanical, electrical, shrinkage, and thermal properties of ultra-high performance concrete (UHPC). The stable dispersion of CNTs was achieved using well-dispersed CNT suspension and confirmed by consistent decrease in electrical resistivity. The autogenous shrinkage was effectively reduced by over 30% by incorporating around 0.5 wt% CNT content. While thermal conductivity was gradually increased with increas