ABSTRACT
The resilience of mechanically stabilized earth structures in elevated pH backfill conditions have typically been a concern due to the potential for elevated degradation due to hydrolysis. An investigation of the reduction in tensile strength of coated polyester (PET) geogrids exposed to pH of 10 was performed. Arrhenius modeling was used to extrapolate the degradation rate of the geogrid tensile strength to 20°C over a 75-year design life and determine the appropriate reduction factor for durability in higher pH environments. This study also identifies the importance of product specific testing by evaluating two types of PET geogrids and the limitations of only using CEG and molecular weight as guidelines for determining reduction factors. The two geogrid types exhibited distinctly different tensile strength degradation. The disparity in tensile strength degradation confirms the importance of the materials and the geogrid manufacturing processes in selecting appropriate durability reduction factors for field applications.
