## 2 Mechanical and Durability Properties of Asphalt Concrete and Concrete
### Influence of Fibers and Recycled Materials from Civil Construction on Pavements' Performances  
The increasing growth of urban sectors has led to a higher usage of natural resources and the generation of vast quantities of CDW. With around 1.3 billion tonnes of solid by-products annually from world cities, it is expected to increase to 2.2 billion tonnes by 2025 [55]. CDW, when reused as aggregates in new construction, can be known as RCAs from the demolition of concrete structures, or RAP from the pavement repair process. Table 3 shows the CDW's compositions and the waste recycling percentages in some countries. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Countries**} & \multicolumn{4}{c}{**CDW Composition 1**} & \multirow{2}{*}{**CDW Recycling**} \\ \cline{2-2} \cline{4-5}  & **RCAs, Mortar, and** & & & **CDW Materials 2 (\%)** \\  & **Ceramic Waste (\%)** & & & **Order** \\ \hline Germany & 45.0 & 35.0 & 20.0 & 90.0  \\ Belgium & 81.0 & 11.0 & 8.0 & 89.0  \\ South Korea & 65.0 & 19.0 & 16.0 & 98.0  \\ Denmark & 83.0 & 9.0 & 8.0 & 81.0  \\ Netherlands & 77.0 & 16.0 & 7.0 & 92.0  \\ UK & 65.0 & 30.0 & 5.0 & 52.0  \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Construction and demolition waste (CDW) characteristics and recycling processes in different locations worldwide. Figure 6: The overall experimental methodology, represented by a block diagram (adapted from [53]). In other countries, the CDW recycling rate is not significant, such as in Portugal (9.0%) and Brazil (16.1%) [57; 58]. However, in Japan and Australia, it should be noted that financial support for the high technology required for separation and processing has resulted in increased motivation in the industrial sectors to use recycled materials [59]. Then, sustainable pavement design is essential for AP and ICBP construction. Studies into the knowledge and application of CDW are ongoing, mainly in AC, CPB, and the pavement's base layer [15; 16; 60; 61; 62; 63]. Furthermore, various waste plastics such as polyethylene terephthalate (PET) and low-density polyethylene (LDPE), can be used as an alternative to replace aggregates. Then, the research by [PERSON] et al. [64], [PERSON] et al. [65], and [PERSON] et al. [66] for AC; and the studies by [PERSON] et al. [67], [PERSON] et al. [68], and [PERSON] et al. [69] for CPB can be cited. Incorporating CDW aggregate into pavement structures provides environmental and economic benefits. Because of the workability and air permeability, a relevant proposal would include this by-product in permeable pavements. Previous AP or ICBP has a surface layer that allows air and water to pass easily from the pavement top and through an interconnected network of void structures to the underlying layers. [PERSON] [17] analyzed some materials for fibers, such as nylon, steel, coconut, glass, and polypropylene. In addition, concrete blocks for ICBP were investigated with and without fibers. The results showed that the compressive and flexural strength properties increased at 7, 14, and 28 days of age. Furthermore, fibers were also used in AC, such as cellulose and polyester materials [70]. Cellulosic fibers present essential advantages such as a low cost and a zero carbon footprint, and they enjoyable physical and mechanical properties, e.g., low density and well-balanced stiffness [71]. Then, cellulosic fibers can be helpful for AC due to decreased stop binder drainage, preventing their loss during storage and transport [72]. Table 4 lists studies on the influences of fibers, RCAs, and RAP on AC, CPB, and granular materials properties for the bases of pavements. Research by [PERSON] et al. [60] highlighted that AC with RCAs would require a higher bitumen content for optimum performance than the control mix R0. The alternative mixtures, CR80 (7.5%), CR100 (8.0%), and FCR100 (9.9%) showed an optimum binder content above the 7% maximum recommended for the mix design.