# Transition Effects in Bridge Structures and Their Possible Reduction Using Recycled Materials
## 6 Perspectives and Research Gaps
It is particularly important that these are minimally processed waste materials with a long-term use that will not be an ongoing burden on the recycling industry (also due to material limitations and a finite number of cycles). These materials that do not require expensive and energy-intensive processing and production \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Material** & **Tensile Strength** & **Density** & **Strength-to-Weight** \\
**[-]** & **[MPa]** & **[g/cm\({}^{3}\)]** & **Ratio** \\  & & & **[kNm/kg]** \\ \hline PET & & & \\ reinforced with glass fiber & 196 & 1.80 & 109 \\ in a ratio of 55\% & & & \\ \hline PET & & & \\ reinforced with carbon & 220 & 1.45 & 152 \\ fiber & & & \\ in a ratio of 30\% & & & \\ \hline PET & & & \\ reinforced with basalt fiber & 113 & 1.63 & 69 \\ in a ratio of 30\% & & & \\ \hline rPET & & & \\ reinforced with glass fiber & 140 & 1.75 & 80 \\ in a ratio of 50\% & & & \\ \hline rPET & & & \\ reinforced with glass fiber & 135 & 1.66 & 82 \\ in a ratio of 40\% & & & \\ \hline rPET & & & \\ reinforced with glass fiber & 122 & 1.58 & 77 \\ in a ratio of 30\% & & & \\ \hline Steel S235 JR & 360–510 & 7.85 & 46–65 \\ \hline Steel S355 & 470–630 & 7.85 & 60–80 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of the properties of reinforced polymers to steel (based on [199; 200; 258; 201; 202; 259; 203; 204; 205; 206; 207; 208; 209; 200; 201; 202; 203; 204; 206; 207; 208; 209; 201; 202; 204; 205; 208; 209; 201; 202; 206; 201; 209; 202; 203; 204; 205; 206; 207; 208; 209; 200; 201; 209; 200; 202; 205;processes can be defined as low-processed materials or minimally processed materials [265]. These, firstly, are effective, and secondly, they fit into the policy of sustainable development. Post-waste reinforced polymer composites can be successfully considered as such. Material in civil engineering can significantly manage large quantities of waste and ensure their utility for an extended period. The design period, which is often 100 years and is in fact much longer after renovations, also has a positive impact on the possible effectiveness of material recycling. The construction of transportation infrastructure involves increasingly larger structures. This leads to increased vertical loads on the ground and, in the case of bridges and retaining structures, additional horizontal forces (pressure). The most commonly applied solutions to these problems are costly ground reinforcement techniques (such as piling, various types of columns) or enhancing slope stability and retaining structures (using ground anchors or nails). Moreover, the availability of high-quality natural materials (coarse sands, gravels, aggregates) is often limited, and their transportation over significant distances is uneconomical. An alternative, more cost-effective solution to these issues might involve the use of substitute materials. In future research, a critical aspect will be the integration of the abutment with the ground using reinforcing bars, along with selecting the composite's composition and shaping the geometry of the bar structure to achieve the required stiffness. It seems that there may be problems with the material's fatigue, its brittle failure pattern, and low ductility. However, the authors provide for the possibility of modifying the composition of the composite, thus giving the material the desired properties. There is a clear gap in the potential use of composites made from recycled materials in shaping transition zones in integral bridges. Future perspectives aim to propose a new design solution for bridge support structures based on the system of integral bridges, where the abutment will be closely linked to the embankment. In the future, a spatial structure will be designed and analyzed, ensuring cooperation between the abutment and the embankment. Through this, the change in the stiffness (flexibility) of the subgrade along the length of the structure and transition zones will be gradual, predicting a significant reduction in the transition effect.