Abstarct: Asphalt pavements are multilxayer systems that can be reinforced by geosynthetics. Geosynthetics are often installed by asphaltic coats between asphalt laxyers to ensure the distribution and transfer of stress between them and the asphalt mixture. Damage to the geosynthetic connection with asphalt laxyers can cause increased stresses in the upper pavement laxyers and ultimately lead to premature failure. Moisture penetration into pavement laxyers is one of the most destructive factors in the connection of tack coats with geosynthetics and asphalt mixtures. In the present study, direct shear test was used to investigate the long-term effects of moisture on the bond strength of tack coats. In this regard, cylindrical asphalt samples made in the laboratory are connected in pairs by tack coats baxsed on pure bitumen 60-70 to form pairs of final samples. Three types of geosynthetics including: geotextile, bonded geogrid and chicken wire (representing extruded geogrids) were used to make the pairs. To evaluate the effect of bitumen modification with anti-stripping additives, a commercial additive baxsed on fatty acid polyamines in the amounts of 0.2, 0.3 and 0.4% was used. In order to simulate the long-term effects of moisture on the tack coats connections, AASHTO T283 standard moisture conditioning and a proposed moisture conditioning were used. The results showed that the AASHTO T283 moisture conditioning does not have the ability to simulate the long-term effects of moisture on tack coats. The analysis of the results also revealed that used anti-stripping additive could not have an effect on the shear strength of tack coats connections. In addition, it was observed that the use of geosynthetics - especially geogrids - between asphalt laxyers may reduce the shear bearing capacity between them. The weakest shear performance was observed in the specimens containing the extruded geogrid, but in general the specimens with and without geosynthetics showed almost the same moisture sensitivity.