# Sustainable Concrete with Recycled Aggregate from Plastic Waste: Physical-Mechanical Behavior
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & & & & & & & & & Mixed PET/rubber \\  & & & & & & & & X & & Mixed with steel \\ [PERSON] and [PERSON], 2024 [11] & X & & X & & & X & & & fibers \\ [PERSON] et al., 2022 [12] & X & & & & & & X & & \\ [PERSON] et al., 2021a [22] & X & & X & & & & X & & \\ [PERSON] et al., 2022 [14] & X & & & & & X & & & \\ [PERSON] et al., 2021 [15] & X & & & & & X & & & Mixed \\ [PERSON] et al., 2021b [17] & X & & & & & & X & & PET/PP/PEAD \\ [PERSON] and [PERSON], 2022 [16] & X & & X & & & & X & X & Mixed fibers; PP \\ [PERSON] et al., 2022 [18] & X & & & X & & & X & & and PET \\ [PERSON] et al., 2022 [13] & X & & & & & & & X & X \\ [PERSON] et al., 2021c [36] & & & & & & & & Mixed plastics \\ [PERSON] et al., 2022 [21] & X & & & & & & X & & Mixed PET, \\ [PERSON] et al., 2022 [37] & X & & & & & & X & & HDPE, PP \\ [PERSON] et al., 2022 [20] & X & & & & & X & & & \\ [PERSON] et al., 2022 [19] & X & & & & & X & & & \\ [PERSON] et al., 2023 [7] & X & X & X & X & & & X & X & X & Review \\ [PERSON] et al., 2021 [24] & & & & & X & & & & \\ [PERSON] et al., 2023 [25] & & & & & X & & & & Mixed PVC/glass \\ [PERSON] et al., 2015 [26] & & & & & X & & X & & \\ [PERSON] et al., 2024 [23] & & X & & & X & X & & & \\ [PERSON] et al., 2023 [27] & & & & & X & & & Review \\ [PERSON] et al., 2019 [28] & & & & & X & & & & \\ [PERSON] et al., (2021) [29] & & & & & X & & X & & \\ [PERSON], [PERSON], et al., (2022) [30] & & & & & X & & & Mixed nanographite \\ [PERSON] et al., (2019) [31] & & & & & X & & & Mortar \\ [PERSON], [PERSON], et al., (2022) [32] & & & & & X & & & \\ [PERSON] et al., (2022) [33] & & & & & X & & & & \\ [PERSON] et al., (2025) [34] & & & & X & & & & Mortar \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Types of recycled plastic aggregates used in previous studies. Regarding the degree of settlement, some studies [38; 39; 40] have suggested that as the percentage of RPA increases, the workability tends to decrease. This can be explained by different reasons: First, plastic residues affect the viscosity of the mixture and increase its consistency and its sharper and non-uniform shape [7], which can lead to poor bonding between the interfacial transition zone of the cement paste and the RPAs [12; 22]. In this sense, some investigations have studied applications for self-compacting concrete (SCC). [PERSON] et al. (2022) found that when 5% RPA was added, the slump decreased by only 2% concerning the reference mixture [20]; similar results were found by [PERSON] and [PERSON] (2024) when they added 10% fine rubber aggregate, reporting losses of 2% [11]. Regarding the basic mechanical properties, such as compressive strength, flexural strength, tension strength, and modulus of elasticity, some studies have found that they decrease as the percentage of RPA substitution increases. However, favorable results have been obtained with 5-10% substitutions [14; 15; 22], with outcomes remaining similar to the reference mixture [20]. In response to this loss of properties, some researchers have studied the addition of cementitious materials [21], heat treatments [17], and fibers [11] to reverse this trend and generate concretes that can compete for structural use or that resemble conventional concrete. Contrary to the above results, some studies have found that the properties of the reference mixture can be slightly improved. [PERSON] et al. (2022) found that the compressive strength increased when 5% PET gravel was used [18]; meanwhile, by using 10% PET aggregate, [PERSON] et al. (2022) found gains of 3% [13], and [PERSON] et al. (2022) found gains of 9% [37]. In addition to the basic mechanical and physical properties, thermal properties have been studied. [PERSON] et al. (2022) found that adding PET aggregates reduced concrete's thermal conductivity by up to 33% [19], while [PERSON] et al., (2022) found reductions of up to 59% when 100% RPA was added [21]. On the other hand, when evaluating the durability properties, [PERSON] et al.