Influence of temperature on tensile strength and stiffness of geogrid reinforcement

Abstract

Geosynthetic reinforcement materials are known to be load-, strain-, time- and temperature- dependent. Under operational conditions in reinforced soil structures, these materials can be expected to creep to different degrees depending on their structure, method of manufacture and constituent polymer type. Recently, the influence of load, strain and time has been quantified using a hyperbolic isochronous stiffness model. This model is used to estimate the tensile load in a polymeric reinforcement material to compute the maximum tensile load in geosynthetic MSE wall layers under operational conditions using the AASHTO Stiffness Method. However, the stiffness method model was calibrated using laboratory creep data collected at ambient laboratory temperatures in the vicinity of 20℃. In situ measured temperatures in monitored MSE walls in the field can vary significantly below and above this reference temperature both spatially and temporally. Consequently, it may be expected that the stiffness of polymeric materials may also vary depending on temperature, which in turn will influence the strength and stiffness of the polymeric reinforcement. This paper uses data collected from the literature and unpublished sources to quantify the influence of temperature on the mechanical strength and load-strain time behaviour of typical geosynthetic reinforcement products manufactured from polypropylene (PP), high-density polyethylene (HDPE) and polyester (PET) polymers. The results are compiled to demonstrate the quantitative influence of temperature on tensile strength and reinforcement stiffness.