Utilization of Quarry Waste and Granulated Rubber Mix as Lightweight Backfill Material

Abstract

In the present investigation, an attempt has been made to propose a lightweight backfill material using industrial wastes, namely quarry waste and granulated rubber. Granulated rubber was added in varying percentages (5%, 10%, 15%, 20%, 25%, and 30%) to quarry waste for obtaining lightweight material. Laboratory investigation has been performed in the present study to examine the physical, chemical, and geotechnical properties of quarry waste and the geotechnical behavior of quarry waste–granulated rubber (QWGR) mixes. Using granulated rubber as additive, the unit weight of quarry waste material was found to reduce from 21.8 to 14.1 kN/m3 for QWGR30 mix. The friction angle of quarry waste was obtained to be 51.2°, which increased by about 14° with rubber addition for the QWGR30 mix. The permeability of quarry waste was found to improve from fine sand to coarse sand range with the granulated rubber inclusion, making it an efficient backfill material. QWGR30 mix was found to be an efficient lightweight backfill material with reduced lateral pressure by about 73% and 85% compared to quarry waste and conventional sand, respectively. The economic savings of the project on backfill material by using QWGR30 over conventional sand would be around 8.35%.