## 6 Concluding Remarks  
Multifunctional cementitious composites can play a crucial role in monitoring the health of transportation infrastructures, detecting traffic, de-icing, providing grounding systems, shielding against electromagnetic interference, and harvesting energy. These capabilities are enabled by incorporating electrically conductive fillers, which fall into two primary categories: metal-based and carbon-based fillers. This review presents detailed information on the components, performance metrics, influencing factors, and the challenges associated with the fabrication and application of these self-sensing materials. Additionally, it explores recent advancements in the practical deployment of self-sensing cementitious composites in transportation infrastructure. The following key conclusions can be drawn from this review:  
Figure 27: (**a**) Smart pavement setup; (**b**) working modes [286], published by Elsevier (2023). Various conductive fillers can be utilized in the fabrication of multifunctional cementitious composites. Their performance depends on multiple factors, including the type, content, combination, and characteristics of conductive fillers (e.g., length, thickness, and aspect ratio). Therefore, selecting an appropriate conductive filler is paramount to optimizing the self-sensing properties of cementitious composites. Additionally, the cost of conductive fillers varies depending on their type. While some may be more affordable, they may not significantly enhance multifunctional properties, whereas others, though expensive, may considerably improve performance. Thus, achieving a balance between cost and effectiveness is essential. Hybrid conductive fillers are often preferred to optimize both performance and cost-efficiency. * The percolation threshold of conductive fillers is a critical factor in the fabrication of multifunctional cementitious composites. Conductive fillers must be incorporated in sufficient quantities to substantially enhance electrical and thermal conductivity; however, beyond a certain threshold, further addition does not yield a significant increase in conductivity. * The configuration and material composition of electrodes also influence the performance of multifunctional cementitious composites. In this regard, both contact and non-contact electrode systems can be employed, with each having specific advantages depending on the application. * Several challenges hinder the practical application of multifunctional cementitious composites. These include the agglomeration of conductive fillers, the polarization of electrical signals, and cost and environmental concerns. To address these challenges, proper dispersion techniques must be employed to prevent agglomeration, optimized electrode configurations and measurement systems and sufficient conductive fillers should be used to minimize signal polarization, and sustainable materials, such as waste-based materials, should be considered to reduce costs and mitigate environmental impact. * Multifunctional cementitious composite pavements have potential applications in various domains, including traffic monitoring, structural health monitoring (SHM), de-icing/snow melting, grounding systems, electromagnetic interference shielding, and energy harvesting. While the studies reviewed in this paper highlight the diverse field applications of these materials, their real-world implementation has largely been limited to small-scale pilot projects. Therefore, further research is needed to address existing challenges and enhance the feasibility of the large-scale deployment of these self-sensing materials in practical field conditions. Despite significant advancements, several research gaps remain, necessitating further investigation:
* While the influence of conductive filler type and content has been extensively studied, the impact of matrix materials (e.g., sand, gravel, binders, and other additives) has received limited attention.