Abstract: As a special polymer material, geosynthetics is widely used in hydraulic, transportation and environmental engineering. In its service period, the capability of maintaining mechanical properties is of vital importance to the stability of the whole project. The aging properties of geosynthetics are important for predicting the accurate life time of geosynthetics, which is a current hot research topic. Outdoor photo-oxygen aging test on HDPE geogrid was carried out at the outdoor test base of Yangtze River Scientific Research Institute. Test results showed that in the initial 9 months, the tensile strength of geogrid remained unchanged or even increased due to secondary compensatory responses to the UV aging. UV provided required energy for chemical crosslinking, which resulted in the polymer crosslinking reaction and slight contraction in woven fabric. As a result, the tensile strength of geogrid increased in the initial period (9 months), but decreased after 9 months. The long-term research results of the test base could provide first-hand data for the physical and mechanical indexes of the aging properties of geogrid under outdoor exposure.

Key words: geogrid, HDPE, photo-oxidation, outdoor test, aging property, tensile strength