Published in Journal of Solid Waste Technology and Management, Vol. 44, No. 3, pp. 270-280 AUGUST 2018 Chemical, Mineral and Microstructural Characterization of Solid Wastes for Use as Auxiliary Additives in Soil Stabilization Jijo James 1 and P. Kasinatha Pandian 2 1 Associate Professor in Civil Engineering, SSN College of Engineering, Rajiv Gandhi Salai, Kalavakkam – 603110, India; jijothegreat@gmail.com 2 Principal and Professor in Civil Engineering, Karpaga Vinayaga College of Engineering and Technology, Chinna Kolambakkam, Padalam – 603308, India; pknp2020@gmail.com Abstract The study involved the characterization of five solid wastes viz. Phosphogypsum (PG), Ceramic Dust (CD), Press Mud (PM), Bagasse Ash (BA) and Coconut Shell Powder (CSP) in order to understand their suitability as additives to primary binders in soil stabilization. The materials were collected from their sources and were prepared in the laboratory for characterization. They were subjected to various tests including loss on ignition, x-ray fluorescence, x-ray diffraction and scanning electron microscopy tests. The results of the characterization were analysed using ASTM standard for natural pozzolans as well as literary evidence. Based on the investigation, it was found that only ceramic dust was able to achieve the minimum requirements for natural pozzolan in accordance with ASTM code C618. However, based on literary evidence it was found that CD, BA and PG were also capable of providing pozzolanic benefits. Keywords: Characterization, Mineralogy, Microstructure, Solid Wastes, Additive, Stabilization 1 INTRODUCTION Solid waste generation over the years has grown rapidly with the advent of machines and industrial mass manufacturing processes. Industrial revolution, considered as a turning point in the history of human civilization, contributed to the mass production of products as well as by-products, the latter of which resulted in disposal and management problems. Solid state wastes that remain at their place of disposal are called as solid wastes. Solid wastes can be classified as industrial, agricultural, domestic and mineral wastes based on their source of generation (Sabat and Pati 2014). World over, cities generate about 1.3 billion tonnes of solid wastes annually, expected to increase to 2.2 billion tonnes by 2025 (Hoornweg and Bhada-Tata 2012). Sustainable management of solid wastes through its utilization in various avenues has become a thrust area of research. Solid wastes reuse in soil engineering has become one such avenue for management of wastes with solid wastes being used in soil stabilization as stabilizers and additives (James and Pandian 2015, 2016a). A lot of solid wastes have been investigated by researchers and have been found useful not only as a construction material but also an effective material for soil amendment. There have even been attempts to generate a synthetic soil by using combinations of solid wastes (Disfani et al. 2009, James et al. 2017). Sewage sludge ash, Silica fumes, Sugarcane bagasse ash (BA), Groundnut shell ash, Marble dust, Rice husk ash, Rice straw ash, Locust bean waste ash, Egg shell ash, Cement kiln dust, Lime kiln dust, Sawdust ash, Waste paper sludge ash, Incineration ash, Limestone dust, Cement by-pass dust, Wood ash, Bottom ash, Calcined paper sludge, Palm oil fuel ash, Pumice waste, Lime sludge, Construction and demolition waste, Quarry dust and Crushed glass are some of the wastes that have been adopted successfully in soil improvement applications. However, before the utilization of any waste in a particular application, their Accepted Manuscript