The Asphalt Tack Bond Shear Strength Apparatus mounts in most Marshall Stability Test Load Frames and determines the shear strength of tack coat material between two asphalt layers. The heavy steel frame holds a specimen against a fixed plate while a moveable shear plate mounted on roller bearings is positioned over the shear plane. Lateral load on the specimen is controlled by a calibrated spring with a dial indicator to display force. The shear plane gap is 0.5 in (12.5mm), and maximum shear travel is also 0.5 in (12.5 mm). 4in (102mm) or 6in (152mm) diameter cores are mounted using the included adapters. A similar model is available for testing 100 and 150mm (3.94 and 5.91in) diameter samples. The Tack Bond Shear Strength Apparatus is compatible with most Marshall Load Frames with daylight openings of at least 10in (254mm).