The building sector accounts for 40% of the total energy consumed in Europe at annual basis, together with the relevant Greenhouse Gas (GHG) emissions. In order to mitigate these impacts, the concept and establishment of the Nearly Zero Energy Buildings (NZEBs) is under continuous and intensive research. In fact, as the energy used for buildings’ operation becomes more efficient, impacts resulting from the buildings’ embodied energy become of more importance. Therefore, the selection of building materials and components is of high significance, as these affect the energy performance and potential environmental impacts of the building envelopes. The objective of this study is to perform a preliminary Life Cycle Assessment (LCA) on advanced multifunctional building components, aiming to achieve lower embodied emissions in NZEBs. The advanced components analyzed are composite panels for facade elements of building envelopes, providing thermal efficiency. The design of sustainable building envelope systems is expected to upgrade the overall environmental performance of buildings, including the NZEBs. The findings of this study constitute unambiguous evidence on the need for further research on this topic, as substantial lack of data concerning embodied impacts is presented in literature, adding to the growing discussion on NZEBs at a whole life cycle perspective across Europe. This research has shown that the electricity required from the manufacturing phase of the examined building components is the main contributor to climate change impact and the other environmental categories assessed. Sensitivity analysis that has been performed indicated that the climate change impact is highly depended on the electricity grid energy mix across Europe. Taking into account the current green energy transition by the increase of the renewable energy sources in electricity production, as well as the future upgrade of the manufacturing processes, it is expected that this climate change impact will be mitigated. Finally, the comparison between the CLC thermal insulator and other foam concretes in literature showed that the materials of the building components examined do not present any diversions in terms of environmental impact.
High electrical conductivity, along with high piezoresistive sensitivity and stretchability, are crucial for designing and developing nanocomposite strain sensors for damage sensing and on-line structural health monitoring of smart carbon fiber-reinforced polymer (CFRP) composites. In this study, the influence of the geometric features and loadings of carbon-based nanomaterials, including reduced graphene oxide (rGO) or carbon nanofibers (CNFs), on the tunable strain-sensing capabilities of epoxy-based nanocomposites was investigated. This work revealed distinct strain-sensing behavior and sensitivities (gauge factor, GF) depending on both factors. The highest GF values were attained with 0.13 wt.% of rGO at various strains. The stability and reproducibility of the most promising self-sensing nanocomposites were also evaluated through ten stretching/relaxing cycles, and a distinct behavior was observed. While the deformation of the conductive network formed by rGO proved to be predominantly elastic and reversible, nanocomposite sensors containing 0.714 wt.% of CNFs showed that new conductive pathways were established between neighboring CNFs. Based on the best results, formulations were selected for the manufacturing of pre-impregnated materials and related smart CFRP composites. Digital image correlation was synchronized with electrical resistance variation to study the strain-sensing capabilities of modified CFRP composites (at 90° orientation). Promising results were achieved through the incorporation of CNFs since they are able to form new conductive pathways and penetrate between micrometer-sized fibers.