Thickness reduction of the pavement structure and effective utilization of locally available materials can ensure the conservation of natural resources as well as reduction in carbon emissions. This study aims to utilize locally available sandy soil, stabilized with cement and a silica-rich additive, for the base layers of flexible pavements. Unconfined compressive strength (UCS) and durability testing was undertaken on samples prepared with various cement and additive dosages to determine the optimal cement and additive dosages. Laboratory findings indicated considerable enhancement in the strength and durability due to addition of silica-rich additive to cement stabilized soil. Specifically, the durability of cement stabilized soil with additive increased by 74% compared to cement stabilized soil without additive. Based on the findings of the laboratory study, a pavement section for a National Highway (NH-66) project in the Kerala state, India, is designed. Life cycle assessment (LCA) is performed in terms of carbon emissions by implementing cradle-to-gate methodology, and the reduced carbon footprints are assessed by comparing with that of a pavement with granular aggregate base. Carbon emissions are found to have reduced by 42% using the soil stabilized base with cement and additive compared to that of the granular aggregate base. The reduction in carbon emission is primarily due to reduction in thickness of bituminous layers and associated reduction of aggregate quantity in base layer of the pavement.