Abstract
An on-site installation survivability study of polyvinyl chloride-coated polyester flexible geogrids from a single manufacturer, placed in three types of commonly used pavement subgrade material, was performed to evaluate the amount and degree of installation damage. A series of singlerib strength tests, in-isolation junction strength tests, and wide-width tensile tests was performed to evaluate the strength of reduction due to the installation procedure. The results of the study indicated that installation damage to a flexible geogrid is a function of grain size distribution and angularity of backfill materials, and lift thickness. The test results showed that the tensile strength retained for flexible geogrids placed within clayey gravel, poorly graded silty gravel, and well-graded crushed stone gravel is 84 percent to 95 percent, 66 percent to 88 percent, and 57 percent to 88 percent. The reduction factor for tensile strength due to installation damage is related significantly to soil type and varies from 1.05 to 1.74. The retained strength of junction for flexible geogrid ranges from 71 percent to 100 percent for various types of subgrade material. The reduction factor for junction strength due to installation damage varies from 1.00 to 1.40 for different types of soil. Additionally, 2 percent of the maximum load is recommended as the preload for single-rib tensile strength test. Comparison of the test results shows that wide-width tensile strength of the test geogrids is about 10 percent to 20 percent lower than that obtained from single-rib tensile strength tests.
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