Potential Investigation of Stabilised Fuming Furnace Slag for Road Construction

Abstract

Fuming furnace (FF) slag is one of the industrial waste materials which is generated during extraction of zinc metal at the zinc industry. It is deposited at the designated FF slag yard near the plant area with very limited use. As a result, the deposits are increasing year after year posing threat to the environment and occupying large area of precious land. The present research explores the possibility of using this waste material in the road construction. The tests like Scanning electron microscope (SEM), Energy dispersive spectrometer (EDS) and X-ray diffraction was carried out on FF slag. To improve its geotechnical properties, it was mechanically stabilised with jarofix (another waste material generated from the same zinc industry) in the range of 25 to 75 percent. Apart from compaction characteristics, shear strength and consolidation characteristics of these mixes were studied to conclude about its feasibility in embankment and granular layers of road pavement. These mixes were further chemically stabilized with cement in the range of 3 to 9 percent to investigate their potential application in sub base and base layers of road construction. Compressive and durability characteristics of these mixes were also studied. Detailed laboratory study concluded that FF slag is a porous; amorphous cohesionless coarse grained material with high angle of internal friction. Engineering properties viz. dry density, CBR, and shear strength characteristics improved significantly after mechanical stabilisation with jarofix. These parameters of FF slag were compared with other industrial waste materials. Unconfined compressive strength and durability characteristics indicated suitability of cement stabilised slag-jarofix mixes for sub base and base layers of road pavement. It was concluded that about 20-30 percent of FF slag can be used as a replacement of fine aggregate in these granular layers. A typical pavement design indicated that it is possible to reduce the total pavement thickness of about 13 percent by using cement stabilised slag-jarofix mix.