<p>This study examined the effects of controlled interface texture and tack coat application rate on interface shear strength (ISS). The interaction between these two factors has not yet been explored. Double-layered asphalt concrete (AC) specimens were prepared using (i) a new hot-mix asphalt (HMA) layer and (ii) an aged field core as a bottom layer, with a new HMA layer as the top layer. Direct shear tests were conducted on these specimens with varying texture depths and orientations, using SS-1&#xa0;h tack coat at residual application rates of 0, 0.04, 0.06, and 0.08 gal/yd². Controlled texture depths were generated on new HMA and field cores. The top HMA layer was compacted over each bottom layer using a gyratory compactor, and ISS was evaluated under horizontal deformation using the direct shear test. Shearing was done parallel, perpendicular, and at 45° to the texture orientation. The highest value of ISS was observed at 0.06 gal/yd² in most conditions. Two-way ANCOVA indicates that the texture depth is significant in all groups, while the application rate is significant in most cases, except perpendicular texture-shear orientations. Interactions between application rate and texture were mostly insignificant, except for the smooth surface specimens. For conventional milled surfaces, the application rate is marginally significant. Three-way ANCOVA confirmed a strong texture-shear orientation effect, with perpendicular orientations yielding the highest ISS, followed by 45° and parallel orientations. New HMA specimens show a sharp increase in ISS due to texture depth compared to the field cores. This study found that controlled grinding/grooving enhances interlayer bonding and reduces tack coat dependence.</p>