Construction and Demolition Waste as a Sustainable Backfill for Geosynthetic-Reinforced MSE Walls

In rapid urbanization, the construction of mechanically stabilized earthen (MSE) walls has found its inevitable part for which the natural backfill material is becoming scarce. Urbanization can itself answer this problem of scarcity if proper utilization of construction and demolition waste (CDW) is made possible. Proper detailed characterization is necessary to find the suitability of the material as an alternative for depleting natural sand. CDW material processing is minimal all around the world and the characteristics of the processed material vary from place to place. Characterization of various fractions of the CDW material collected from a waste processing unit in India is done by detailed experimental investigations. The results are compared with standard regulations to find the suitability of using the heterogeneous mixture of CDW material, as fill material in MSE walls. From the comparison, it was found that two different fractions of CDW material can be utilized as backfill of geosynthetic-reinforced MSE walls. Further, numerical modeling of an MSE wall was done using finite element program Plaxis. The deformation and stress–strain response of MSE wall backfilled with various fractions of CDW were promising. For Fraction 3 and Fraction 4 CDW, the deformation is reduced by 23% and 86%, respectively, compared to ideal backfill material. Present research highlights a sustainable way of managing the waste generated from the construction and demolition activities focusing on value addition of the material utilizing as a backfill of geosynthetic-reinforced MSE walls.