Experimental investigation of interface treatment technique on interface shear bond fatigue behavior of Ultra-Thin Whitetopping

The bonded concrete overlays on existing asphalt pavements are classified into three subcategories namely whitetopping, thin-whitetopping and Ultra-Thin Whitetopping (UTW). The design service life of UTW overlays depends on several factors such as interface bond strength, slab thickness, slab size, material strength and underlying material condition. The quality of the interface bond depends on both surface preparation and the UTW placement procedure. The interface bond between two layers helps in the monolithic action of the pavement section by shifting the neutral axis from the middle of the UTW slab to the bottom of UTW slab. The composite action had a direct impact on the long-term performance of the UTW overlays. To assure good bonding, milling method is usually applied at the interfaces during UTW overlay construction. The interface bond strength due to milling technique can be measured with the help of several devices arranged by different laboratories. This paper investigates the interface shear bond strength and shear fatigue behavior of UTW pavement for different interface treatment techniques. For this experimental purpose, a laboratory direct shear testing method and procedure was used. Two interface treatment technique like groove and piercing method have been analyzed. Interface treatment with piercing technique had shown highest shear bond strength and k-modulus values. Incorporating groove interface technique with an inclination of 0-45 degrees and piercing interface treatment has been proposed. The interface shear bond fatigue behavior of piercing treatment technique with different debonding conditions are discussed. As expected the increase in debonding leads to decrease in interface shear stress and fatigue performance.