Currently, tons of high-quality borosilicate glass are discarded to landfills each year, taking up space on valuable land. Within the existing soda-lime glass recycling industry it is not possible to use recycled borosilicate glass due to its higher melting temperatures and a dif
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Currently, tons of high-quality borosilicate glass are discarded to landfills each year, taking up space on valuable land. Within the existing soda-lime glass recycling industry it is not possible to use recycled borosilicate glass due to its higher melting temperatures and a difference in chemical composition. In fact, borosilicate glass disturbs the recycling process of soda-lime glass, resulting in more unused waste. Borosilicate glass is a type of glass that has favourable properties for application in the built environment, such as high optical qualities and a low thermal expansion coefficient. However, due to its high melting temperature and high energy consumption it is much more expensive to produce compared to the more common soda-lime glass. Nevertheless, in general it is possible to recycle glass waste almost 1:1, therefore, it is a waste to dump such high-quality glass on landfills. Cost and energy consumption issues related to the fabrication of borosilicate glass can be decreased by using recycled crushed glass (cullet) to the melt. Cullet reduces the required melting temperature, resulting in a lower energy consumption and a cheaper production process. However, a fully closed borosilicate glass recycling loop is not possible. The current borosilicate glass product industry has very strict quality control. Recycling glass introduces contaminations in the glass melt, which could generate flaws and cracks in the end product. This means it is not feasible to use recycled glass in these industries. This research proposes a promising approach to tackle the borosilicate glass waste problem and the recycling issues related to contamination: using the collected borosilicate glass waste to produce cast glass components. The bulkiness of such a component allows for a higher amount of impurities without risk of failure and a decrease in quality. In addition, cast glass allows for self-supporting facade systems in many configurations due to their increased cross-section and high-compressive strength capability. To allow disassembly of such a cast glass facade system a dry-interlocking system is proposed. Such a system can ‘close’ the recycling loop of borosilicate glass by feeding in waste glass from traditional borosilicate products into a new cast glass recycling loop. The challenges and opportunities regarding recycling borosilicate glass were researched by conducting experiments. Several mixtures of borosilicate glass with different chemical compositions were cast into small specimens to assess the mixability and corresponding mechanical properties of recycled borosilicate glass. In terms of mixability, good results were observed when the cullet is ground to powder, although there is a risk of contamination during grinding and thus degrading quality. Using fine cullet is also promising, but there is an increased risk of internal stresses. Specimens with a homogeneous chemical composition showed that it is possible to create borosilicate glass components with a lower firing temperature. In addition, these homogeneous specimens illustrated through a three-point bending test that recycled borosilicate glass has comparable mechanical properties to non-recycled borosilicate glass. This indicates that recycled borosilicate glass is suitable for application in cast glass components for use in the built environment. Due to time constraints and the preliminary nature of this research the number of specimens was relatively small. This thesis presents a dry-interlocking cast glass component system applied in a case study. The case study concerning the existing Casa da Música is meant to illustrate the possibilities of applying high-quality glass in an aesthetically pleasing facade system and to showcase the possibilities of recycling borosilicate glass. At the end-of-life of this design the facade can be disassembled. The components can either be directly reused in another building or recycled again. The proposed solution can reduce the growing amount of glass waste.