EAF STEEL SLAG AS SUPPLEMENTARY CEMENTING MATERIAL

Abstract

Large scale recycling of steel slag as a cementitious additive to cement mortar and/or concrete was investigated in this paper. As the material component of steel slag is highly variable, this EAF slag is gathered from plant site of Dong Tien steelmaker in Ba Ria-Vung Tau province. Chemical compositions of slag consist almost the high content of free CaO, MgO and iron, Fe_xO_y. Lower content of cementitious mineral C3S, C2S endorses relative low hydraulic reactivity in comparing with Portland cement. After grinding slag to particle size < 90 μm (Blaine 3400 cm²/g), blended cement–steel slag with 10 to 40% by mass of slag were formulated. Both steel slag-cement Portland and steel slag-granulated blast furnace slag (GBFS)-cement Portland system were introduced to analyze early age and later age property of mortar sample. Preliminary results of resistance remark appropriate formulation of 20% of slag. By adding 20% GBFS in such product, practical application could be considered due to the typical enhancement of durability property of cement mortar in severe condition (sulfate, chlorhydric acid). Others, by considering an approach of slag treatment to improve hydraulic reactivity as the GBFS materials model present. The mineralogical composition and some cementitious properties of obtained product would be discussed for a perspective of new clinker steel slag.