This study was conducted to propose a simulation model for corrosion cracking of cover concrete in reinforced concrete structures located on land and subjected to airborne chloride. Chloride penetration has been known to have great influences on the design corroded mass due to the fact that it changes the corrosion initiating time and corrosion rate. Accordingly, a chloride penetration model was proposed for reinforced concrete structures located on land. This model was verified with the drawn core of concrete specimens taken from structures that were free from the rain washout effect. In this study, the corrosion rate of reinforcing steel was also proposed by considering the change in degree of saturation in concrete due to environmental conditions. With the changes in the degree of saturation, the effective corrosion rate is changed according to three controlling factors: the conductivity of the concrete, the chloride concentration and the supply flux of oxygen. Therefore, the design corroded mass is the integration of the effective corrosion rate from the corrosion initiating time to the design time. Moreover, a numerical formula for limit corroded mass, which causes cracks in cover concrete, was developed and proposed. The accuracy of the formula was approximately 25% as compared to the experimental results of previous studies. Thus, the cracking time is the time when the design corroded mass is greater than the limit corroded mass. Additionally, the simulations at the time of cracking in cover concrete were compared with three actual reinforced concrete bridges subjected to airborne chloride.

This study examines the relationship between shear force and horizontal relative displacement of Lshape shear connector by means of beam type test method. An equation for maximum shear force of the specimen which takes into account the effects of size of the shear connector and the concrete strength was proposed. It was found that shear force-horizontal relative displacement relationship can be represented by a unique enveloped curve by normalizing shear force by maximum shear force and horizontal relative displacement by the height of the shear connector. The predicted maximum shear forces and shear forcehorizontal relative displacement relationships were found to agree with the experimental results.

This study examines the relationship between shear force and horizontal relative displacement of Lshape shear connector by means of beam type test method. An equation for maximum shear force of the specimen which takes into account the effects of size of the shear connector and the concrete strength was proposed. It was found that shear force-horizontal relative displacement relationship can be represented by a unique enveloped curve by normalizing shear force by maximum shear force and horizontal relative displacement by the height of the shear connector. The predicted maximum shear forces and shear forcehorizontal relative displacement relationships were found to agree with the experimental results.

This paper presents a strength model for Portland cement mortar with and without partial replacement mineral powders, limestone filler, blast furnace slag, and fly ash. The model was developed based on hydration heats and microstructure developments. The investigation was conducted on cylindrical mortar specimens with different water-to-cement ratios, different types of cements, and different curing conditions. The compressive strength of mortar was found to have a linear relationship with the ratio of hydration heat coupled with the porosity. Consequently, a strength model for mortar compressive strength, which is a summation of all heat-pore components multiplied by their own strength contribution factors, was established. The calculations of compressive strength using the proposed model agreed well with the experimental results in terms of cement paste, mortar, and concrete.