Geotechnical Characterization of Construction and Demolished (C&D) Waste

Natural well-graded granular materials are conventionally used as a fill material for various geotechnical applications. However, due to high demand for granular material, illegal dredging of sands from the river beds is on the rise. On the other hand, a study carried out by Centre for Science and Technology, New Delhi, has reported that huge amounts to the tune of 530 million tonnes of Construction and Demolished (C&D) Waste were generated during the year 2013 in India. This C&D waste includes waste from demolished structures due to renovations of existing structures and repair of roads, flyovers, bridges, etc. In addition, enormous debris is generated following disasters such as that during the Uttarakhand floods in 2013. Typically, C&D waste is dumped in municipal landfills. This study presents the efficacy of crushed concrete and concrete rubble for use as an alternate backfill material in mechanically stabilized earth (MSE) walls. Crushed concrete (CC) is collected locally from the demolished structures of Ordinance Factory Campus, Yeddumailaram, Telangana, and processed before testing. Various index and engineering properties of CC such as particle-size distribution, specific gravity, water absorption, permeability, compaction characteristics, and crushability are ascertained and compared with TxDOT and MORTH specifications for fill materials. Corrosion resistivity of CC is determined by pH test, and the chemical composition of CC is obtained from X-ray fluorescence (XRF) studies. CC is classified as well-graded gravel (GW) as per IS: 2720 (Part 4)-1985. The study indicates that C&D waste, traditionally considered as waste material, can be reused viably as backfill for MSE walls.