Reinforcement of interlaminar mechanical properties between rigid and flexible layers of semi-rigid base asphalt pavement using interlayer treatment

To increase the interlaminar mechanical properties between the asphalt course and the semi-rigid base course, a novel method is proposed, which utilises pits to lock and bond them. Three types of pavement with different treatments are constructed and tested to assess their interlaminar mechanical properties. The experimental results show that the shear strength and pulling strength of the interface connected by nine pits of 18 mm between the asphalt mixture and the cement-stabilised macadam are, respectively 41.6% and 29.6% higher than those of the prime coat asphalt. When the ambient temperature rises, the maximum interlaminar shear strength of the pavement treated with pits decreases with the slowest rate, becoming 16.6% lower than that of the prime coat asphalt. When the shear rate increases, the interlaminar shear strength of the pavement treated with pits increases at the fastest rate, resulting to be 28.5% higher than that of the prime coat asphalt. Furthermore, since the size has an important effect on the interlaminar mechanical properties, the larger interlocking area between the asphalt mixture and the cement-stabilised macadam results in the ability to bear greater interlaminar shear strength and pulling strength. The proposed method provides several advantages for future engineering applications.