Evaluation of cement paste containing recycled stainless steel powder for sustainable additive manufacturing

Abstract

Cement is a key ingredient and the most widely used cementitious material in making concrete. Often, numerous materials are mixed with cement in the form of powders (that are mainly supplementary cementitious materials), fillers or others, to enhance the properties and applicability of concrete produced. In the last two decades, additive manufacturing has grown rapidly; however, large amounts of waste metal powder from additive manufacturing were generated at the same time. Metal powders are generally expensive, and recycling of such metal powder causes associated hazards and environmental stress. Incorporating metal powder into cementitious system may be a solution to utilize metal powders from the additive manufacturing industry and to improve the mechanical strength of cement part at the same time. In this study, a non-conventional Stainless Steel (SS) micropowder, of particle size 40–100 µm was used in cement paste mixture. SS powder is a new material to be used in the cementitious matrix that has not been reported in the literature to the best of authors’ knowledge. Properties of SS micropowder modified cement paste samples were characterized and compared to that of a control (reference) mixture. The results indicated that addition of 5% SS micropowder to cement paste (by volume of the mixture) was an optimum quantity that improved the strength and durability of the mixture whereas 2 and 8% SS addition had negative effects. Further study to explore its use at higher dosages as replacement of cement is recommended.