A moisture-curable adhesive composition comprises a polymer component selected from a silane-terminated polyalkylene oxide and/or a polyurethane; a plurality of amino-silane modified wollastonite fibers having an average aspect ratio of from about 1.5:1 to about 12:1 and an average fiber length of from about 6 μm to about 825 μm; at least two fillers, wherein one of said fillers is untreated and a second of said fillers is treated with a modifier selected from the group consisting of a fatty acid derivative, a silane, a titanate, and mixtures thereof wherein at least one of said fillers is irregularly shaped; and a rheology modifier. The composition preferably further comprises a plurality of irregularly-shaped crumb rubber particles having an average particle size of between about 0.5 to 1.5 mm. The composition is useful for adhering tiles to surfaces, especially large format tiles to substantially vertically-extending wall surfaces.