Concrete is a composite material that is widely used in a construction project. The evaluation of concrete structure is very important in order to determine its strength and quality. Concrete is commonly evaluated by using the ultrasonic pulse velocity (UPV) method, which adopted the concept of measuring time of a first arrival of the received signal. Hence, this paper aims to evaluate the first arrival time of the detected ultrasonic signals based on different conditions of concrete structure. A simulation study was conducted by using COMSOL Multiphysics software version 5.6. Data collected were categorized into three sections, including in concrete model with inclusion of air hole, crack, and rust. From the simulation results, concrete models with inclusion of air hole showed an increment in the arrival time as the size of air hole increase. For the concrete models with rust, the arrival time were significantly increased in 20-mm and 40-mm rust, however it turns down as the size of rust reached 60-mm. The results also indicated that transverse crack took a longer arrival time compared to other orientation of crack.
