Segregation is a persistent phenomenon in granular materials. Studying the effect of segregation on the deformation behaviour of granular materials is essential. In this work, the Discrete Element Method(DEM) is used to perform simulations of the triaxial test on granular assemblies segregated based on the size of the particles. The macroscopic load response obtained from simulations is validated experimentally. A triangulation-based interpolation scheme is utilized to obtain the strain distribution in the granular assembly during the simulation. During the triaxial loading, it has been found that the smaller particles preferentially undergo a higher degree of lateral deformation. The strain distribution also indicates that the smaller particles undergo higher average shear strain than the larger particles. Strain localization is more prevalent in the smaller particles, too. The strength of the assembly does not seem to depend on the presence of segregation. This implies that segregation does not seem to affect the strength of the granular assembly when compared to the mono-disperse cases. However, it does affect the deformation pattern of the granular assembly. The segregation especially seems to strengthen the region containing larger particles.