Effect of curing temperature on carbonation behavior of steel slag compacts

Abstract Steel slag is now being explored as a novel prefabricated building material with high mechanical property and capability of carbon dioxide (CO2) storage when subjected to carbonation curing. Limited researches were focused on the effect of curing temperature on the carbonation performance of steel slag prefabricates. In this paper, the compacted steel slag cylinders were cured in the CO2 atmosphere of varied temperatures ranging from 0 °C to 90 °C. The evolutions of compressive strength and CO2 absorption ratio were tested. The changes of the surface temperature of the samples and the environmental temperature in the pressure tank during carbonation curing were recorded. The phase assemblage and microstructure of carbonated steel slag were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and thermogravimetry (TG) analysis. The results indicate that, in the early carbonation period, elevating the curing temperature is beneficial to the development of compressive strength and CO2 absorption ratio of the steel slag compacts. While, with the prolonging of curing time, the strength and CO2 absorption of samples cured at 0 °C and 90 °C is much lower than the samples cured at intermediate temperatures, i.e., 30 °C and 60 °C.