Geo-synthetics, which are produced with different raw materials and in various structures, are made of polymeric compounds. They have diverse applications in construction industries such as retaining walls, road construction and so on. From both technical and economical point of view, their usage is efficient. Geo-grids, a kind of geo-synthetics, are in grid form which is composed of set of polymeric ribs that have bound to each other. There are empty spaces with determined dimensions among the ribs, which are called “aperture”. The presence of aperture causes interlocking effects of soil particles, stones and etc. Their dimensions vary between 10 to 100 mm. The ribs, usually made of PE, PET and GF, are placed in both horizontal and vertical directions. Numerous studies have been performed on the mechanical properties of woven geo-grids up to now. Since tensile property of warp knitted geo-grids has not been specifically investigated, so this property was covered in this study. Therefore the effect of yarn count, pattern and applying tensile load in different orientations has been investigated. At first, from applying tensile test (based on ASTM D6637) on five different patterns, one pattern was chosen. Each geo-grid was made of high tenacity PET yarn, next each geo-grid was coated with PVC resin. Then, the chosen pattern was knitted with three different yarn count (1000, 1500 and 2000 denier). Finally, tensile load was applied in four different orientations (0, 30, 45 and 90) on these samples. The Anova and Duncan tests were performed on the obtained results. The results indicate that maximum tensile force increased with increasing in yarn counts and increasing in course density in pattern. In addition, maximum tensile force increases as orientation increases from 0 to 90. Also, increasing in maximum tensile force was observed by applying PVC coating.
