Construction material properties of high temperature arc gasification slag as a portland cement replacement

This study investigates a potential beneficial reuse application for high-temperature arc gasification slag (HTAG), a waste product of electricity generated using municipal solid waste as fuel. The potential for the beneficial use of this material for a partial replacement for portland cement was investigated at four levels of replacement (5, 20, 35, and 50%). The heat of hydration was measured for the reference and slag samples by isothermal conduction calorimetry. Results from the study demonstrate that at low replacement percentages the total heat evolution and the compressive strength of the control cement and slag-cement blends are similar. The compressive strength of mortars amended with pulverized and finely milled HTAG slag was measured at 7, 28 and 56 days and the results demonstrate that low replacement percentages (5%) of portland cement with HTAG slag produces comparable strength. Significant decreases in strength and heat were seen when higher replacement percentages (20-50%) were used, however these decreases were partially offset using finer slag. Although the activity index of the slag was relatively low compared to portland cement, an increased activity index can be reached by decreasing the average particle size, suggesting that properly processed HTAG slag does offer potential as a supplementary cementitious material. (C) 2018 Published by Elsevier Ltd.