Characteristic of melted slag from wrought iron industry as green concrete material

Abstract

Utilization waste material on concrete ingredients or its manufacturing that did not harm the environment is the need for the environment sustainability. It is the background of research in concrete design for more environmental friendly as often called green concrete. This work aims to investigate the usability of the melted slag, obtained from local wrought iron industry, as aggregates replacement according to waste material utilization. In particular, it focused on studying the feasibility of replacing the aggregates using melted slag by investigating the basic physical characteristic. Slag is known have a high percentage of silica and ferric oxides, which gives pozzolanic activities that suitable to use as cement blended product. Slag waste used in this work is obtained from the wrought iron industry from Pakis district, Magelang Regency, Central Java, Indonesia. The slag chunk extracted from the furnace then crushed to smaller particle sizing as fine aggregates and coarse aggregates. The aggregates characteristic is observed in relation to gradation test, specific gravity, bulk density, clay lumps percentage, and Los Angeles abrasion value. All of observation parameters are taken consecutively based on SNI and ASTM specification to evaluate its compatibility as concrete aggregates. The current work remarks that the fine and coarse aggregates generated from wrought iron slag do not reveal complete fulfilment in the aggregate specifications of any standard. Even though, the slag fine aggregates could be used in standard or lightweight concrete with further treatment such as crushing to smaller particle size, washing to minimize the clay lumps, and mixing with natural aggregates.