Design and Construction of Road Embankment Using Fly ash in Waterlogged Area
U.K.Guru Vittal, Head, Geotechnical Engg Division, P.S.Prasad, Sr. Scientist, CSIR - Central Road Research Institute, New Delhi.
IntroductionIndia depends primarily on coal based thermal power plants for electricity generation, leading to production of huge quantities of fly ash and subsequently its disposal problems. The solution to this problem lies in gainful utilisation of fly ash. One of the identified areas for bulk utilisation of fly ash is construction of roads and embankments. CSIR-Central Road Research Institute (CSIR-CRRI) during the last two decades has undertaken many demonstration road projects using fly ash for embankment and road pavement construction. Recently, construction of one more embankment was taken up in Delhi by using fly ash. Delhi Government has taken up construction of 'Signature Bridge' and its approaches at Wazirabad across River Yamuna through Delhi Tourism & Transportation Development Corporation Ltd. The eastern approach of this bridge comprises of an embankment of about 1.73 km length. This embankment has been constructed using a mixture fly ash and sand as core material of the embankment with soil cover. The distinguishing feature of this project was use of fly ash as fill material, in a waterlogged area, which had never been attempted before. Hitherto for constructing embankment in waterlogged areas, gravel was being used as per MoRTH Specifications for Road and Bridge Works. However in this project fly ash was successfully used to replace gravel for back dumping operations in waterlogged area.
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