This study uses two different geocell shapes, namely square and hexagonal, to examine how the shape of the geocell affects the performance of unpaved roads. Waste from construction and demolition has been used as an infill material to prepare a pavement base layer. The properties of construction and demolition waste have been referred from Indian Road Congress IRC: 121–2017. The layer thickness of the subgrade and base course materials are considered to be 500 mm and 200 mm, respectively. A base-subgrade system reinforced with a geocell layer has been studied using the Plaxis 3D software. The base-subgrade system has been examined using the Mohr–Coulomb material model. Flexible pavement types that are conventional and unconventional have been compared. The results have been presented in terms of thickness, stress, and deformation to help understand how conventional and unconventional pavement layers performed in comparison. Geocell mattresses in hexagonal shapes perform better than those in square shapes, according to the results of the finite element analysis.