Characterisation of Foundry Sand Waste Material for Road Construction

Different types of waste materials viz. copper slag, zinc slag, steel slag, manganese slag, phosphogypsum slag, cinder, red mud, kimberlite, lime sludge, foundry sand, coal ash, jarofix, jarosite, manganese slag, marble dust etc. are being generated in huge quantity as a bye product from the different industries. Presently, utilization of these waste materials is much more crucial and concern in India due to large amount of production and having very limited application. Foundry sand is one of such waste material produced from foundry industries spreded all over the country. The annual production is about 3 million tons from different foundry industries in India. The unutilized accumulated material is about 25 million tons. The material was collected from foundry industry, Ahmadabad (Gujarat) and characterization was carried out to study its application in the construction of embankment, subgrade and shoulder layers of road. Physical, chemical and geotechnical characterization were carried out considering the application in road construction. The paper discusses about the laboratory test results and development of design specification of its suitability in the road construction. It is observed that foundry sand is a coarse grained material having sand size particles. It can be used in the construction of embankment/subgrade and shoulder layers after modification of geotechnical properties.
A K Sinha, M Vinoth, S R Shankar, V G Havanagi, Scientists, CSIR-Central Road Research Institute, New Delhi, India

Introduction
Foundry sand is an industrial waste material generated from the foundry industries spreded all over the country. It is a natural sand which is used as a molding material in the ferrous and nonferrous metal casting industries. This sand is typically recycled and reused through many production cycles. After several cycles, it becomes unsuitable for the industry and pile up as a waste material, called foundry sand. The total production of this waste sand is about 3 million tons annually.

Fox and Mast (1998) revealed that foundry sand may be used as an embankment construction and its performance is comparable to conventional soil. Kleven et al., (2000) observed that foundry sand can be used in the construction of pavement sub base layer (Kirk, 1998; Goodhue et al., 2001). Yucel and Ahmet (2005) advocated that soil-foundry sand mixtures blended with cement/lime can be used in the construction of highway sub base layer and as a fill material (Gedik et al., 2008). Luis et al. (2015) used the foundry sand blended with clayey soil for application in base and subbase layers construction and observed that foundry sand - soil mixtures have mechanical properties similar to the conventional material. Foundry sand improved the mechanical properties of clayey soil after blending which may be used in the construction of sub grade (Kumar et al. 2014). Even though, the percentage utilisation of foundry sand is very less in India. Laboratory investigation was carried out to assess the suitability in road construction viz. physical, chemical and geotechnical characteristics. Different geotechnical characteristics that were studied included; grain size analysis, Atterberg limit test, free swelling index test, specific gravity test, Proctor compaction test, CBR test, unconfined compressive strength test, consolidation test, permeability test and direct shear test. The paper discusses the results of laboratory studies and different technical specifications for its use in embankment, sub grade, shoulder and GSB layers of road. Design and stability analysis of foundry sand embankment was also presented under different water saturation condition with seismic factor.