PSI - Issue 64

Gabriella Maselli et al. / Procedia Structural Integrity 64 (2024) 1743–1751 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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implementing circular economy principles (AlJaber et al., 2023). However, as the construction sector is a sector with a high potential for the implementation of CE strategies, it is becoming increasingly urgent to (i) search for innovative materials in the field of civil and construction engineering that, besides being technically performing, represent environmentally friendly and cost-effective solutions, considering the entire life cycle; (ii) promote the adoption of eco-friendly products and technologies, maximising material recovery and avoiding excessive waste production and consequent landfilling. It is also evident that circular economy strategies can reduce the life-cycle costs of buildings (Jansen et al., 2020). According to Slaugter (2001), in fact, costs and time for flexible buildings are reduced by 2 per cent of the initial construction cost within the first renovation. Manewa et al. (2016) argue that buildings designed on the basis of EC principles reduce life-cycle costs, mainly due to lower maintenance. Nevertheless, CE strategies are hampered by several barriers, including higher investment and design costs and a lack of understanding of the benefits of circular design. Therefore, it is becoming increasingly relevant to use approaches that consider life cycle costs. The appropriateness of LCC in economic evaluation has been recognized in the literature, as it is a valuable approach to compare alternative building designs, thus allowing to assess the benefits of operational costs against any increase in initial costs (Ossio et al., 2023; Panza Uguzzoni et al., 2023). However, the barriers that have led to a low application of LCC in the construction field so far have also been recognized. According to Manewa et al. (2021): «Lack of data, awareness of clients, methodology and standardized practices in relation to LCC have hampered quantity surveyors in its limited use». In addition, the use of life-cycle based economic evaluation approaches are still rare in structural engineering. To address these challenges, this paper intends to propose a standardized, flexible and exportable LCC based methodology to: (a) evaluate the life cycle costs of structural materials used in the field of civil engineering; (b) identify among several alternatives the best performing product from both a technical and economic point of view. The article is structured as follows. Section 2 presents a focus on new circular materials that can be an alternative to conventional materials. Section 3 gives an excursus on current approaches to Life Cycle Costing. Section 4 outlines an evaluation methodology uncommon in structural engineering. The last Section discusses the results and provides research perspectives. 2. Innovative and circular materials in the building and construction sector The relevant literature points to the increasing experimentation of fibre-reinforced polymer matrix (FRP) materials both in the context of the restoration of existing structures and for new construction (Shannag and Higazey, 2020; Mak and Fam, 2020). In the context of reinforcing existing structures, the use of FRP composites as construction materials offers several advantages, mainly stemming from the possibility to customise such materials through the combination of fibres with a polymer resin matrix (Hu et al., 2020). The fibres provide most of the stiffness and strength, while the matrix binds the fibres together, between fibers and between the composite and the external loads and supports. This flexibility allows designers to select materials that meet specific requirements and offers ample opportunities to reinforce conventional materials used in civil construction (May et al., 2020). Furthermore, compared to metals, composites are ideal for applications where corrosion is an issue, such as composite bars and grids, pre- and post-tensioned cables (Kuzina et al., 2018). Due to their corrosion and solvent resistance, composite materials also require less maintenance than traditional materials, thus reducing total life cycle costs (Naser et al., 2019). In addition to FRP materials, research is also increasingly directed towards the use of innovative and eco-friendly construction materials to ensure higher performance in new and existing structures in terms of thermal and acoustic insulation. Several studies have focused on the advantages of recycled and waste materials to replace virgin materials. Advantages include the lower use of raw materials and soil, as well as lower energy consumption during the entire production process. Recent studies show that industrial, agricultural, construction and demolition waste, recycled aggregates and lightweight aggregates (LWA) made from waste materials can be good candidates to partially replace natural aggregates (Colangelo et al., 2021). While the FRP and eco-friendly materials mentioned above have been the subject of experimentation mainly as structural reinforcement of concrete or in the form of bars and/or stirrups, the use of composites as genuine construction materials has recently become more widespread. These are glass fibre-reinforced profiles (GFRP) made using the pultrusion technique. Like all FRP materials, pultruded GFRPs have a high strength-to-weight and stiffness to-weight ratio, excellent corrosion resistance, and thus superior durability to traditional construction materials (Report EUR 27666 CEN TC 250). Pultrusion is a continuous production process used to produce constant cross-sectional