Carbonation of cementitious materials is one of main causes of reinforcement corrosion and CO₂ diffusivity influenced by microstructural characteristics of the cementitious materials is a decisive parameter for the carbonation rate. This study focused on establishing a multifactor functional model to calculate the CO₂ diffusivity of carbonated cementitious materials. Because CO₂ gas flows through carbonated zone, it is necessary to estimate CO₂ diffusivity of carbonated concrete. Many factors on the CO₂ diffusivity, such as the diffusivity in vapor, tortuosity, microstructural characteristics of cement paste, contribution of aggregate, and reduction of porosity due to carbonation, were considered. Apparent and effective CO₂ diffusivity were calculated according to the absence or presence of moisture in the pore system of concrete, and the results were compared with previous research.

The resistivity of a concrete structure exposed to chloride ions indicates the risk of early corrosion damage, because a low resistivity is related to rapid chloride penetration and to a high corrosion rate. Concrete resistivity is a geometry-independent material property that describes the electrical resistance, which is the ratio between the applied voltage and resulting current in a unit cell. The current is carried by ions dissolved in the pore liquid. While some data exist on the relationship between the moisture content and electrical resistivity of concrete, very little research has been conducted to evaluate the effect of chloride on the conduction of electricity through carbonated and non-carbonated concrete. The purpose of this study is to examine the effect of chloride concentration on the surface electrical resistivity measurement of carbonated and non-carbonated concrete. Chloride concentration had influenced the resistivity of concrete and the relationship showed a linear function. However, for concrete under the combined deterioration of carbonation and chlorides, a reduction in porosity due to the carbonation had a greater effect on the electrical resistivity than the increase in conductivity due to the chloride ions. Conclusively, this paper suggested the quantitative solution to depict the electrical resistivity of concrete with various chloride concentrations.

The paper presents an analytical investigation of the effect of vertical ground motion on the selected 13 reinforced concrete (RC) frames with different geometric configurations. For this purpose, earthquake ground motions with various vertical‐to‐horizontal peak acceleration ratios are selected to which a suitable scale factor is applied to match with seismic hazards of Korea. The methodology involves the evaluation of the structural responses of RC frames subjected to the selected records by means of nonlinear time history analyses. The results from the analysis are compared with results from studies of the case of horizontal‐only excitation. The effect of the vertical earthquake component on damage of RC frames is considered at both the global and the local levels. The effect of vertical ground motion on axial force, shear demand, and shear capacity of RC columns is investigated to assess failure on a local level. In particular, the shear capacity is evaluated by using both the conservative method of a design code and more realistic predictive approaches. The results of the extensive analyses indicate that vertical ground motion can significantly affect the response of RC members in terms of axial force variation and shear capacity. These results point to the conclusion that vertical ground motion needs to be included in analysis for assessment and design.

Due to the increasing tendency to construct taller and more slender buildings, the need to address aerodynamic and induced dynamic forces (inertial forces) under both service and strength-level wind loads has become more important. Currently, application of performance-based wind design (PBWD) to reduce induced dynamic forces applied through the acceptance of inelastic deformation is permitted as an alternative design approach, in which wind load can be reduced with respect to the yield strength and ductility of the structure. However, reduced wind load smaller than aerodynamic forces may not ensure proper inelastic wind design. The results of this study indicate that to avoid huge ductility demand due to damage accumulation, the yield strength for structural systems with zero-to-modest post-yield stiffness must be larger than the aerodynamic forces. Moreover, due to uncertainty in the number of occurrences of peak aerodynamic loads applied to a structure during a wind event, it would be advisable for systems with large post-yield stiffness to consider upper limits of aerodynamic forces.

Textile-reinforced concrete (TRC) is highly anticipated as an alternative to reinforced concrete due to its ability to enable lightweight design, free formability, and improved ductility. In this study, TRC panel test specimens were fabricated and four-point loading flexural tests were performed to examine the flexural characteristics of TRC panels reinforced with carbon fabric, and to investigate the effect of the fabric reinforcement ratio, anchorage length, and surface treatment of fabric. Furthermore, the flexural behavior of the test specimens was numerically analyzed using the general section analysis concept of reinforced concrete and compared with the experimental results. Due to bond failure between the carbon fabric and the concrete matrix, the TRC panel showed a large decrease in flexural performance in terms of flexural stiffness, flexural strength, cracking behavior, and deflection. This low performance was improved by increasing the fabric reinforcement ratio, anchoring length, and sand–epoxy surface treatment of the anchorage. Comparing the numerical calculation results with the experimental results, the deflection of the experimental results was approximately 50% larger than the numerical calculation results. This is because the perfect bond between the carbon fabric and the concrete matrix failed, and slip occurred.