Masoud Jafarnezhad - Master of civil engineering, majoring in road and transportation, Zanjan Branch, Islamic AzadUniversity, Zanjan, Iran
Seyyed Amir Hossein Beheshti - Department of Civil Engineering, Zanjan Branch, Islamic Azad University, Zanjan, Iran
Seyyed Mahdi Sajjadi - Department of Civil Engineering, Zanjan Branch, Islamic Azad University, Zanjan, Iran

Geogrids are another group of geosynthetics that are made of polyester and polyethylene or a combination of these or other similar materials and are produced in three thicknesses in different thicknesses, sizes and dimensions. In this research, the effect of geogrid on the pavement behavior and its final bearing capacity is addressed. It will be assumed that on a sandy bed, there is a concrete pavement reinforced with geogrid with specific and fixed characteristics and loads, and the interaction of pavement and geogrid is modeled. According to the results, with increasing the number of geogrid layers, the amount of subsidence under the concrete pavement has decreased. Accordingly, if geogrid is not used, the amount of settling was equal to ۱۰۰.۶ mm, which was increased to ۷۱.۶ mm by adding a layer of geogrid, which was a decrease of ۲۹%. Also, this amount of reduction is set at ۶۵% if three geogrid layers are used. In addition, by increasing the number of geogrid layers from ۱ to ۳, the amount of subsidence has increased from ۷۱.۶ mm to ۳۴.۵ mm, which is a decrease of ۵۱%. With increasing the number of geogrid layers, the bearing capacity of the pavement has increased. Accordingly, in case of not using geogrid, the amount of carrying capacity was equal to ۱۶۲ tons, which was increased to ۲۰۰.۷ tons by adding a layer of geogrid, which was a growth of ۲۴%. Also, this amount of increase is set at ۳۸% if three geogrid layers are used. In addition, with the increase in the number of geogrid layers from ۱ to ۳, the amount of carrying capacity has increased from ۲۰۰.۷ tons to ۲۲۳.۴ tons, which is an increase of ۱۱%. By increasing the distance between the geogrid layers, initially the subsidence decreases and then it increases. By increasing the distance between the geogrid layers from ۰.۵ m to ۱ m, the amount of concrete pavement settling has increased from ۶۸.۲ mm to ۵۴.۹ mm, which has been a decrease of ۱۹%. Then, with increasing the distance from ۱ meter to ۲ meters, the amount of subsidence increased from ۵۴.۹ mm to ۷۳.۷ mm, which was a growth of ۳۴%. Therefore, the distance of ۱ meter between the geogrid layers is the optimal distance. By increasing the distance between the geogrid layers, first the bearing capacity is increased and then it is reduced. By increasing the distance between the geogrid layers from ۰.۵ meters to ۱ meter, the amount of paving bearing capacity has increased from ۱۹۶.۶ tons to ۲۱۳.۷ tons, which is an increase of ۹%. Then, with increasing the distance from ۱ meter to ۲ meters, the amount of carrying capacity decreased from ۲۱۳.۷ tons to ۱۸۴.۱ tons, which was a decrease of ۱۴%. Therefore, the distance of ۱ meter between the geogrid layers is the optimal distance.

Bearing capacity, Sitting, Concrete pavement, Geogrid