No abstract

No abstract

No abstract

No abstract

IntroductionThe River Yamuna is a most important river of Delhi, capital of India and stretched within the zone of 22 km from Wazirabad to Okhala. Within this stretch 22 major drains of the capital, Delhi is connected and continuously discharging highly contaminated sediments, sewage and sludge effluents directly into it resulting in the rise of its bed level due to siltation day by day [5]. Thus, before monsoon every year dredging of the soils from each drain becomes essential. As recorded during 2010-2013 the total quantity of dredged soils removed from all the drains is approximately 8, 30,000 m 3 and in 2016 the quantity of dredged soil removed is about 3, 38,132 m 3 [17]. Due to scarcity of open land, the Government of Delhi is facing great problems to dispose these high quantities of dredged soils every year. The earlier practice of dumping of dredged soils into landfill areas or into open places caused a lot of environmental problems and suffering to local public which forced management authority for alternative solutions of its disposal. Currently, stabilization and solidification (S/S) processes have been recognized AbstractLarge amount of sediments are dredged from connecting drains of River Yamuna as a part of its regular maintenance in Delhi. These dredged soils generally considered as waste due to its poor engineering properties. In this study attempt has been made to improve strength, durability and immobilize contaminants of the contaminated dredged soil collected from Najafgarh drain by mixing it with different proportion of cement-bottom ash mix so that it can suitably fulfill the requirements of highway subgrade materials. Compaction test, California bearing ratio test, wetting and drying test, toxicity characteristic leaching procedure leachate test and scanning electron microscope test were performed on the contaminated dredged soil specimens and the results indicated that cement-bottom ash mix was effective in improving the engineering properties of the contaminated dredged soils. Also, the test results of the contaminated dredged soil stabilized with cement-bottom ash mix were better in comparison to cement alone. From the study it reveals that the optimum proportion of additive to be used to improve properties of the contaminated dredged soils was 10% cement + 10% bottom ash mix for use it as a highway subgrade fill materials. Gupta et al. Geo-Engineering (2017) Page 2 of 13 Gupta et al. Geo-Engineering (2017) 8:20 to treat such type of contaminated dredged soils containing heavy metals and to use it as valuable resources. Wilk et al. [28] reported the stabilization and reuse of contaminated dredged material from Former Wood Treating Facility, Port Newark, New Jersey and New York harbour dredged sediments using cement. He found that dredged material from Port Newark when treated with 8% cement achieved unconfined compressive strength greater than 1.7 MPa which was suitable for its use as base material for pavement whereas the dredged soil from New York harbour site got stabilized to...