The displacement response of a cylindrical and an apsidal shaped structural unit under blast loading is compared in this study using the finite element code LS-DYNA utilizing two different concrete constituent models, namely the Riedel-Hiermaier-Thoma (RHT) model and the Continuous Surface Cap Model (CSCM). The blast load generated by an emulsion explosive corresponding to six scaled distances is used for the study. The validation of the displacement response is carried out by utilising the Newmark numerical integration procedure using the linear acceleration method. The unique apsidal shape in its displacement response performs better across all the simulations indicating superior blast resistance. CSCM model returns conservative values of displacements in the study. The study finds that the RHT model requires higher stress levels for consideration of dynamic strengths and hence returns lower displacement values for the instances considered in this simulation. This study recommends the use of an apsidal unit and the use of RHT constitutive model in the simulations.