Silicon manganese is an essential alloy in the manufacture of steel which impart hardness & strength and performs as an oxidizing agent. Large amount of non bio-degradable slag is produced during the manufacture of alloy which was thought of being used http://images.google.co.in/imgres?imgurl=http://www.sharpferro.com/images/hc-si-mn_small.jpg&imgrefurl=http://www.sharpferro.com/product_specification.htm&usg=__5lH3ImPsg0lfeC-iwnG5Jw4JUlU=&h=227&w=368&sz=28&hl=en&start=16&um=1&tbnid=7vllkL2PXo%20in the construction industry as aggregates in flexible and rigid pavements as well as Ballast for rail track construction. Use of SiMn slag requires detailed knowledge of its chemical, mineralogical, pozzolanic, volume expansion and strength properties in addition to reaction kinetics which plays an important role in the final valorization of slag as pozzolanic material. The paper discusses prominent experimental investigations on Silico Mangenese Slag as non-conventional or manufactured aggregate being investigated as Material for Road and Rail Track Construction. The tests were carried out to determine its suitability as an aggregate in various construction fields. Initially the index properties were found out for subsequent use in designing of concrete.