International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Index Copernicus Value (2013): 6.14 | Impact Factor (2014): 5.611 Volume 4 Issue 12, December 2015 www.ijsr.net Licensed Under Creative Commons Attribution CC BY A Study on Characteristics of Subgrade Soil by Use of Foundry Sand and Iron Turnings Brajesh Mishra M. Tech., Assistant Engineer, U.P. Cane Development Department, Lucknow, India Abstract: It is due to continuous increase in industrial by-products and wastes, solid waste management in present scenario has become a global environmental concern. Due to costly disposal of waste materials and shortage of landfills , it is the need of the hour to reuse the waste materials in various construction activities in a eco-friendly way. Foundry sand is one of such industrial by-product causing hazardous effect on environment and human being. The natural properties of foundry sand can be used to utilize it in sub-grade of a pavement to avoid any possible threat to environment and giving a way for safe and economical disposal of the same. Other industrial waste is iron turnings which can also be reused. This study is about the improvement of compaction and sub-grade characteristics of sandy clayey soil by blending it with foundry sand and iron turnings in specified proportions. The various strength parameters i.e. compaction characteristics and California Bearing Ratio (CBR) of different mix proportions of soil, foundry sand along with iron turnings were studied. It was observed that the Maximum Dry Density(MDD) and California Bearing Ratio (CBR) values increases up to certain proportion of addition of foundry sand in sandy clayey soil and thereafter on further addition of foundry sand it starts decreasing. The same trend was also observed with the introduction of iron turnings in selected soil-foundry sand mixture. As a result a suitable composition with optimum percentage of clayey soil, foundry sand and iron turnings was found, which can be effectively used in the construction of sub-grade of roads and embankments giving a way for good and economical construction. Keywords: California Bearing Ratio (CBR), Maximum Dry Density(MDD), Foundry sand, Iron turnings, Industrial by-product. 1. Introduction A large amount of sand as a part of metal casting process is used in Metal foundries. In the process sand is recycled and reused many times. When the sand can not be further utilized in the foundry process, it is removed and termed as “foundry sand”. It is high quality silica sand which is a by-product of casting process of ferrous and nonferrous metals. The properties of foundry sand is dependent on type of casting process and the type of industry. High quality silica sands are used by the industries in their metal casting process. Foundry sand consists of green sand and resin sand. Green sand typically comprise of high quality silica-sand, 5to 10% bentonite clay, 2 to 5% water and around 5% sea coal. Green sand is most commonly used around 90% of the molding material by foundries. Resin sands are high- quality silica sand usually held together with organic binder in conjunction with catalyst in different hardening procedures. Resin sands are mostly used for “cores” that produce cavities that are not practical to produce by green sand molding operations. Table 1: Typical properties of green foundry sand Property Value Test Method Specific gravity 2.40-2.70 ASTM 854-06 Bulk Density gm/cc 1.60 AASHTO T084 Absorption % 0.76-6.20 ASTM C128 Moisture Content % 0.10- 15.0 ASTM D 2216 Hydraulic conductivity 10ˉ³ to 10ˉ9 ASTM D 5084 California Bearing Ratio (CBR)% Average 20 ASTM D 1883 Internal friction angle 33° - 43° ASTM D 3080 Magnesium sulphate soundness loss % 5-15 ASTM C88-05 Foundry sand is basically fine aggregate. It can be used in following ways-  Same way as natural sand  In embankments & other similar civil engineering applications  Flow able fills  Hot mix asphalts and Plain cement concrete (PCC)  Agriculturally as top soil In engineering applications in India at present foundry sand around 5 to 7 lacs tones is used annually. Due to paucity of funds in India specially for low volume village roads there is a requirement of cheaper materials for construction. Foundry sand along with iron turnings and locally available materials can be used in embankments and sub-base of rural roads. So one can utilize a large volume of foundry sand in road construction projects to minimize the cost of construction. Many researchers in past have shown that foundry sand can be used successfully in various civil engineering construction. Some of those are listed below-  Highway bases and retaining structures (Kirk,1998: Mast and Fox,1998: Goodhue et al,2001)  Landfill Liners (Abichou et al, 1998, 2004)  Asphalt concrete (Javeb and Lovell,1995)  Flow able fill (Bhat and Lovell,1996)  Pavement bases (Kleven et al,2000) Existing research has shown that foundry sand can play its role in geotechnical construction due to its comparable properties with sand-bentonite mixtures. (Abichou et al, 2004) 1.1 Need for Utilization of Foundry sand In India at present around 6500 foundries are in operation with a total casting output around 2.8 million tones. India is a leading producer of casting in the world. The foundry units in India are mostly located in Rajkot, Agra, Howrah, Jamnagar, Kolhapur, Coimbatur and Hyderabad. Annually around 2 million tones of foundry sand waste is produced in Paper ID: NOV152228 1262