White Ordinary Portland Cement blended with superfine steel dust with high zinc oxide contents

The addition of steel waste in the form of slags and dust to cement is beneficial to the environment because waste can be immobilized, and thus, decreasing the waters contamination. In this paper, paste and mortar-based Portland cement samples with up to 70.0 wt% of steel dust were investigated. Since it is known that for one ton of Portland cement fabricated 900 kg of CO2 are emitted to the environment, the addition of steel waste to cement is very beneficial. Moreover, since steel dust reduces the amount of needed cement in concrete, it reduces the final cost of concrete significantly. Additionally, the manufacturing processing was conducted entirely at room temperature; therefore, the negative impact of cement in the environment is reduced. Scanning electron microscopy and X-ray diffraction characterization were conducted in order to investigate the microstructure of the samples. In addition, compression, density, and flow table tests were done over all samples. Thermo-gravimetric tests were performed to analyze the waste thermal stability. The effect of the potential hazardous components of this waste in water was analyzed through leachability tests. For all samples, compressive strength ranged from 73 to 2.5 MPa. The lowest strength value corresponded to 70 wt% of waste. Results show a solution for using this waste as admixture in cements and concrete, and therefore as a method for reducing cement paste in buildings and infrastructure. (C) 2016 Elsevier Ltd. All rights reserved.