PSI - Issue 67

G. Goracci et al. / Procedia Structural Integrity 67 (2025) 30–38 G. Goracci/ Structural Integrity Procedia 00 (2024) 000 – 000

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aggregates and binders increase the reflectivity of pavements and asphalts, substantially impacting urban temperature reduction. Although the benefits of cool materials are well-documented, challenges remain, including higher initial costs, the need for periodic maintenance, and aesthetic considerations. Ongoing research focuses on developing more cost-effective cool materials, improving their durability, and integrating them with other urban sustainability initiatives. Amidst these technological advancements, our approach to addressing this dual challenge is rooted in the holistic integration of multiple environmental strategies. We focus on utilizing industrial waste materials to capture CO 2 , developing cool cement to mitigate UHI, and enhancing human comfort in urban environments (see Fig 1). Specifically, Periwinkle shells, a by-product of the food industry, are rich in calcium carbonate and portlandite, making them suitable for CO 2 sequestration through mineral carbonation. Similarly, steel slag, a by-product of steelmaking, contains a high percentage of calcium oxide (CaO) and magnesium oxide (MgO), enhancing its potential for CO 2 capture. These carbonated materials are used to develop cementitious materials with high solar reflectivity. Utilizing such cool cements in urban infrastructure, such as pavements, roofs, and building facades, significantly reduces surface temperatures. This not only lowers the ambient temperature in cities but also cuts down on the energy required for air conditioning, further reducing CO 2 emissions. Moreover, reduced urban temperatures lead to lower incidences of heat related illnesses and mortality, thereby enhancing public health. Finally, by leveraging the carbonation reactions of industrial by-products, we not only sequester CO 2 and develop materials that contribute to reducing CO 2 emissions, but also address waste management issues, thereby contributing to a circular economy. In conclusion, this multifaceted approach ensures that our strategies not only combat climate change but also foster more sustainable and livable urban environments.

Figure 1 : Scheme of our strategy, starting with the collection of industrial waste materials like periwinkle shells and steel slag. These materials capture CO2 through mineral carbonation and are then used to develop advanced cementitious materials with high solar reflectivity. When applied in urban infrastructure such as pavements, roofs, and building facades, these materials reduce surface temperatures and mitigate the UHI effect. This process sequesters CO 2 , lowers energy consumption for air conditioning, enhances urban liveability, and addresses waste management issues, contributing to a circular economy.

2. Materials And Methods This study investigates two different sample types for CO 2 sequestration and urban cooling: cement paste samples composed of Ordinary Portland Cement (OPC) mixed with carbonated periwinkle shell (PS) ash, and pelletized samples composed of steel slag mixed with Portlandite.