Creep behavior of geosynthetics using confined-accelerated tests

The creep behavior of geosynthetics has commonly been determined using standardized creep tests, which are time consuming and very expensive. In addition, these tests involve the use of in-isolation specimens. Thus they are not likely to consider the overall effect of soil confinement. Confined creep tests conducted at elevated temperature can be used to address these negative aspects of standardized creep tests. This paper presents a pioneering laboratory apparatus developed in order to conduct confined, accelerated and confined-accelerated creep tests. In addition, preliminary tests were performed to assess the new equipment's capability of conducting confined and accelerated creep tests. These tests were performed using a biaxial geogrid, a woven geotextile, and a nonwoven geotextile. The new equipment allowed different conditions to be reproduced. The creep behavior of the nonwoven geotextile and the geogrid was found to be very sensitive to soil confinement. On the other hand, the woven geotextile presented a creep behavior independent of soil confinement. The geogrid results did not agree with reports in the technical literature. Accordingly, these results showed the importance of characterizing the effect of soil confinement in geosynthetics creep behavior. Additionally, these preliminary results showed the potential of the new device to overcome the main negative aspects of standardized creep tests on geosynthetics.