Characterisation of a 3D Printed Alkali-Activated Material Based on Waste-Mineral-Wool at Room and Elevated Temperatures (2024-01)¶

The building sector is the largest energy consumer in the European Union (EU), accounting for approximately 40 % of energy consumption and 36 % of CO2 emissions [1]. The demand for housing is expected to rise because of the increase in global population. Consequently, construction and demolition waste (CDW), which currently constitutes approximately 25–30 % of the total waste generated annually in Europe [2], will also increase, making it necessary to use it appropriately instead of being dumped in landfills. Additive manufacturing (3D printing) has gained significant attention over the last few years and has served as an encouraging method for solving several environmental problems, including the need for both local source materials and minimising waste production. 3D printing enables the production of more complex shapes and has been employed in various fields [3,4]. Additive manufacturing offers advantages such as freedom of design, reduced labour, customisation, automation, waste minimisation, and the ability to build complex structures with inexpensive materials. However, it also suffers from disadvantages such as the formation of voids between layers, which results in higher porosity and reduced adhesion between printed layers and anisotropic behaviour. These disadvantages represent the challenges in additive manufacturing that need to be overcome [5]. Various types of additive manufacturing methods are currently in use, including binder jetting, directed energy deposition, material extrusion, material jetting, powder bed fusion, sheet lamination, and vat photo-polymerization [6]. Extrusion and layered printing are most commonly applied for concrete-type materials [7,8].