Author:

Keywords:

BOF slag, Mineral carbonation, fine aggregate, cement mortar, soundness, leaching, Science & Technology, Technology, Construction & Building Technology, Materials Science, Composites, Materials Science, BOF slag, Mineral carbonation, Fine aggregate, Cement mortar, Soundness, Leaching, OXYGEN FURNACE SLAG, STEEL SLAG, ACCELERATED CARBONATION, ASPHALT MIXTURE, MINERAL CARBONATION, BOTTOM ASH, CONCRETE, STABILIZATION, DURABILITY, PREDICTION, 0904 Chemical Engineering, 0905 Civil Engineering, 1202 Building, Building & Construction, 3302 Building, 4005 Civil engineering, 4016 Materials engineering

Abstract:

Direct mineral carbonation produces a material rich in carbonates and with reduced quantities of free oxides. The aim of this work was to show that such materials can be used in the construction domain. Basic Oxygen Furnace (BOF) slag from the steelmaking process has been traditionally seen as unfit for bounded applications due to its propensity to swelling, resulting from hydration of its high free lime content. Here, BOF slag was crushed to suitable particle sizes, carbonated in an aqueous solution of carbonic acid, and utilized to replace 50% of natural sand aggregate in cement mortars. The mechanical and chemical properties of these mortars were compared to mortars containing non-carbonated slags, and a standard cement mortar as a reference. Tests were conducted to determine mortar paste consistency and soundness, and cured mortar compressive strength and leaching tendencies. The results showed a satisfactory performance for all considered aspects (comparable with the reference) of the mortar sample containing 37.5 wt% (1.5 in 4 parts solids) carbonated BOF slag of <0.5 mm particle size.