Reinforced cast glass

Abstract

Glass casting offers the potential to create complex, large-scale, monolithic structural elements with optimized stiffness and material use. However, glass's brittleness and lack of post-failure redundancy pose safety challenges, especially since conventional float glass safety strategies are difficult to apply to volumetric components. Inspired by reinforced concrete, this study explores embedding metal reinforcement in cast glass directly during the casting process to enhance ductility, redundancy, and recycl-ability by avoiding adhesives. The novelty lies in directly bonding metal to glass using materials with similar thermal expansion coefficients, further allowing contamination-free recycling. Building on previous TU Delft research, we investigate two material combinations with matching thermal expansion coefficients: (i) bor-osilicate glass with F15 Kovar and (ii) soda-lime silica glass with Titanium Grade 2 or 5. Kiln-cast glass beams with a longitudinal metal reinforcement are produced and tested under four-point bending using Digital Image Correlation to assess their mechanical performance. Borosilicate glass specimens reinforced with Kovar demonstrated effective glass-metal interaction but lower strength due to interfacial bubbles, with all specimens failing in shear, in a similar manner to reinforced concrete, while retaining most glass attached to the metal rod. Soda-lime glass specimens reinforced with Titanium exhibited higher failure loads, though specimens reinforced with Grade 2 Titanium failed in bending similar to unreinforced glass. Titanium Grade 5 reinforcement showed potential for strength enhancement and progressive failure, emphasizing the importance of proper reinforcement selection and dimensioning. Finally, we discuss the potential for mate-rial separation at end-of-life and the applicability of this technology for embedded connections in cast glass.