and hydraulic conductivity. The physical and mechanical properties of recycled materials may be affected by the chemical composition of parent materials and recycling process (Kuo et al. 2002). RCA differs from natural aggregates in composition (e.g. presence of mortar). It is more angular and has rougher surface than its virgin aggregate counterparts (Griffiths et al. 2002, Juan et al. 2009; Rathje et al. 2006; Soleimanbeigi et al. 2015). These physical characteristics are believed to augment the friction angle of RCA (Tatsuoka et al. 2005; Rathje et al. 2006). RCA is susceptible to higher-than-normal particle breakdown, which can potentially increase the amount of fines (e.g. particles passing No. 200 sieve), thus reducing hydraulic conductivity and altering the material’s compaction characteristics (Rathje et al 2006). RAP consists of nearly 92-97% aggregates that are coated with asphalt binder (Rathje et al. 2001). The specific gravity of asphalt binder is 1.0-1.04 (Roberts et al. 1996). The low specific gravity of asphalt binder thus lowers bulk values of specific gravity and dry unit weight of RAP. RAP particles have low absorption potential and a low content of fine particles. Because the material consists of angular particles, values of internal friction angles observed in the literature are equivalent to or higher than those of natural aggregates (Rathje et al. 2006; Cosentino et al. 2006; Soleimanbeigi et al. 2012; Edil et al. 2012). A critical characteristic of RAP is its creep potential. The viscoelastic properties of the bituminous coating in RAP may cause excessive creep strains when RAP is subjected to sustained deviatoric stresses (Rathje et al. 2006; Soleimanbeigi et al. 2015). BA’s physical and engineering properties depend on the parent coal type, specific plant processing, and recycling methodology. Gradation varies broadly between samples, and generally varies from well-graded gravel to poorly-graded sand. The presence of iron increases the values of specific gravity of BA. Specific gravity values reported in the literature range from
and hydraulic conductivity. The physical and mechanical properties of recycled materials may be affected by the chemical composition of parent materials and recycling process (Kuo et al. 2002). RCA differs from natural aggregates in composition (e.g. presence of mortar). It is more angular and has rougher surface than its virgin aggregate counterparts (Griffiths et al. 2002, Juan et al. 2009; Rathje et al. 2006; Soleimanbeigi et al. 2015). These physical characteristics are believed to augment the friction angle of RCA (Tatsuoka et al. 2005; Rathje et al. 2006). RCA is susceptible to higher-than-normal particle breakdown, which can potentially increase the amount of fines (e.g. particles passing No. 200 sieve), thus reducing hydraulic conductivity and altering the material’s compaction characteristics (Rathje et al 2006). RAP consists of nearly 92-97% aggregates that are coated with asphalt binder (Rathje et al. 2001). The specific gravity of asphalt binder is 1.0-1.04 (Roberts et al. 1996). The low specific gravity of asphalt binder thus lowers bulk values of specific gravity and dry unit weight of RAP. RAP particles have low absorption potential and a low content of fine particles. Because the material consists of angular particles, values of internal friction angles observed in the literature are equivalent to or higher than those of natural aggregates (Rathje et al. 2006; Cosentino et al. 2006; Soleimanbeigi et al. 2012; Edil et al. 2012). A critical characteristic of RAP is its creep potential. The viscoelastic properties of the bituminous coating in RAP may cause excessive creep strains when RAP is subjected to sustained deviatoric stresses (Rathje et al. 2006; Soleimanbeigi et al. 2015). BA’s physical and engineering properties depend on the parent coal type, specific plant processing, and recycling methodology. Gradation varies broadly between samples, and generally varies from well-graded gravel to poorly-graded sand. The presence of iron increases the values of specific gravity of BA. Specific gravity values reported in the literature range from