Utilizing natural expansive clays that are available on-site as sewer trench backfill can cause destructive deformations due to volume changes, which are caused by seasonal climatic changes. Such deformations result in manhole structures protruding from the surface, which cause damage to the surrounding infrastructure and generate potential trip hazards. In this study, mixtures of recycled materials with minor sensitivity to moisture variations and superior compactibility were investigated using geomechanics theories associated with granular materials as an alternative backfill material. Blends of recycled glass (RG), plastic (RP), and tire-derived aggregates (TDA) were mixed on-site, wetted to the required moisture content (MC), and used to backfill excavated trenches around two manhole structures and extended to approximately 11 m along the trench. A benchmark trial was constructed by backfilling with natural soils available on-site according to the normal procedure. The full-scale trial sites were instrumented using settlement plates and MC sensors at various locations and depths for performance monitoring. The results of approximately 17 months of field monitoring showed that settlements over both areas that were backfilled with recycled blends were <20% of those over areas backfilled with site-won soils. Approximately 82% of the settlements in the recycled blends occurred during construction. In contrast, trenches that were backfilled with site-won soils continued to exhibit deformation due to consolidation and swell-shrink cycles. The outcome of this study could contribute to the United Nations' Sustainable Development Goals, in particular, Goal 12, by improving the industry's confidence in the reuse of wastes in geotechnical applications.