Minkwan Ju 교수

The physicochemical properties of calcined kaolinite clay have an impact on the hydration kinetics of limestone calcined clay cements (LC 3 ). Therefore, this study compares the effects of two types of common clays, namely low-grade kaolinite (LGK) and mixed minerals (MIX), on the characterization, heat of hydration, setting times, and strength development mechanisms in LC 3 . The characterization of calcined clays is initially conducted. After conducting heat of hydration, TGA , and XRD analyse

Estimating the compressive strength of high strength concrete (HSC) is an essential investigation for the maintenance of nuclear power plant (NPP) structures. This study intends to evaluate the compressive strength of HSC using two approaches: non-destructive tests and concrete core strength. For non-destructive tests, samples of HSC were mixed to a specified design strength of 40, 60 and 100 MPa. Based on a dual regression relation between ultrasonic pulse velocity (UPV) and rebound hammer (RH)

This study investigated the punching shear behavior of full-scale, two-way concrete slabs reinforced with glass fiber reinforced polymer (GFRP) bars, which are known as noncorrosive reinforcement. The relatively low modulus of elasticity of GFRP bars affects the large deflection of flexural members, however, applying these to two-way concrete slabs can compensate the weakness of the flexural stiffness due to an arching action with supporting girders. The test results demonstrated that the two-wa

Abstract This study investigated the mechanical behavior of normal strength (NS) and high strength (HS) concrete containing recycled fine aggregates (RFAs). A high slump mixing design was employed, which may be potentially used as filled structural concrete. The compressive strength, tensile strength, and elastic modulus were measured according to the RFA replacement ratio and curing time. In addition, the shrinkage strain was measured in a temperature and humidity chamber over 260 days. The com

The paper describes the mechanical behavior of fine recycled concrete aggregate (FRCA) concrete according to the mineral admixtures. Three types of the mineral admixtures, i.e., fly ash (FA), ground-granulated blast-furnace slag (GGBS), and silica fume (SF), are used and the replacement ratios of FRCA are 50% and 100%. The dosages of the admixtures of FA, GGBS, and SF are determined with the normal dosage (30%, 40%, and 5.0%, respectively) based on the ACI committee reports (No. 232, 233, and 23

This study introduces a glass fiber reinforced polymer (GFRP)-steel hybrid bar with a core of a deformed steel bar (steel core). Six types of the hybrid cross section were considered, and a total of 48 tensile specimens were tested by the uniaxial tensile test to measure the tensile strength and modulus of elasticity of the GFRP hybrid bar. The results of the uniaxial tensile test revealed that the GFRP hybrid bar showed higher modulus of elasticity and lesser ultimate tensile strength than thos

Cross-bracing (X-bracing) is one of the most popular methods of seismic retrofitting. Research results indicate that X-bracing significantly increases structural stiffness and enhances the strength of the structures. However, researchers have also noted that conventional steel X-bracing methods can involve brittle failure at the connection between the brace and the building, as well as buckling failure of the braces. The current research thus investigated the structural properties of a new type