3D-AM Thermally Smart Composites for Highly Sustainable and Energy Efficient Building Design and Retrofitting

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Reducing energy-related CO2 emissions from the construction sector is critical to curbing the unprecedented recent increase in the global mean abundance of carbon dioxide. According to the 2020 Global Status Report for Buildings and Construction, the sector accounts for almost 38% of energy- and process-related CO2 emissions worldwide. In particular, cement production and energy use in construction and its operational phases, and the disposal of demolition waste after the service life cycle, are the major sources of emission related to the building sector. Despite the severe environmental impact, almost all construction projects still rely on decades-old - and unstainable -- methods of construction and retrofitting, which need to be updated with novel methodologies to advance the construction industry toward greater sustainability. To eliminate the environmental impact of cementitious concretes and limit the energy use of buildings while properly recycling construction and demolition wastes (CDW), this research proposes to develop novel, thermally-smart, eco-friendly and energy-saving CDW-based geopolymer composites that can be easily used as structural and insulation/retrofitting materials in new and existing buildings via three-dimensional additive manufacturing (3D-AM) processing techniques. It is expected they will have the advantages of phase change materials (PCMs) in terms of enhanced storage capacity, be completely stable and PCM leak-proof, be optimally designed with conductive fillers for maximizing their thermal conductivity and have high mechanical and durability performance. Further, they will be based entirely on CDW materials through their maximized inclusion as binders, aggregates and hardeners. Hence, the resulting thermally smart composites will be optimized for the 3D printing process by fulfilling the required rheological, thixotropic, mechanical and printability properties of additive manufacturing. The targeted geopolymer composites will be developed to suit any building design and retrofitting application through reinforced building envelope walls and retrofitting/coating techniques. The final performance assessment of these innovative systems will be undertaken on laboratory-scale prototypes under various hot and cold environments to ensure that the targeted thermal performances are achieved. Also, sustainability and cost effectiveness will be ensured from material synthesis to the final application of the developed composites by performing environmental and cost assessment analyses throughout the planned tasks. The outcome of the proposed research will be to greatly reduce energy consumption by the building sector in Canada and around the world, and to find practical, ecological solutions for the mass recycling of landfilled CDW materials. Such energy savings are expected to be a significant advancement toward decarbonizing the construction industry and reducing global CO2 emissions and related climate change impact.