Experimental evaluation of asphalt material for interlayer in rigid-flexible composite pavement

Bond condition between layers in a rigid-flexible composite pavement is a key factor affecting the durability and maintenance of the pavement. High-temperature properties and viscosity of four interlayer asphalt materials were tested by rotational rheometer. Dynamic mechanical temperature sweep tests and shear fatigue tests were also carried out. The results indicated that AR (asphalt with rubber) and SBS modified asphalt are better asphalt materials for an interlayer, as their pavement performances are overall better than those of matrix asphalt A-50 (asphalt of penetration 50) and A-70 (asphalt of penetration 70). Compatibility of matrix asphalt and modifying agent has significant impact on fatigue properties of SBS polymer modified asphalt. SBS modified asphalt is recommended for an interlayer, for its excellent pavement performance and construction convenience. The optimum dosage of SBS modified asphalt is determined by interlayer bond test. The findings of this study could provide an important reference for choosing interlayer asphalt material for rigid-flexible composite pavements.