Influence of Mechanical Damage under Repeated Loading on the Resistance of Geogrids against Abrasion

Abstract

Geogrids are building materials widely used for soil reinforcement that can be affected by the action of many degradation agents throughout their service life. The potential negative effect of the degradation agents should be properly estimated and accounted for during the design phase. The main aim of this work was to study the influence of mechanical damage under repeated loading on the resistance of geogrids against abrasion. Three geogrids (one extruded and two woven) were exposed in isolation to mechanical damage under repeated loading and abrasion tests, followed by the successive exposure to both degradation tests. The damage suffered by the geogrids was evaluated by visual inspection and by tensile tests. Based on the changes found in tensile strength, reduction factors were determined. The reduction factors obtained directly from the successive exposure were compared to those resulting from a method in which the reduction factors obtained for the isolated effect of each degradation agent were multiplied. Results indicated that the abrasion process tended to be affected by a previous exposure to mechanical damage under repeated loading and that the multiplication of the reduction factors obtained for the isolated effects of the degradation agents may not correctly represent their combined effect.

Tensile and Tearing Properties of a Geocomposite Mechanically Damaged by Repeated Loading and Abrasion

“…The mechanical damage under repeated loading tests (for ease of writing, hereinafter designated as RL tests) and the abrasion tests followed standard methods, which, in addition to being described in the respective standards (EN ISO 10722 [22] and EN ISO 13427 [23], respectively), were also described in previous works [12,13,24]. Therefore, in this work, only a short description of these tests is provided.…”

“…The abrasion process was conducted under a pressure of 6 kPa and included 750 abrasion cycles. A schematic of the abrasion tests can be found in Carlos et al [13]. In these tests, the tested side refers to the side of the geocomposite in direct contact with the P100 abrasive.…”

“…The tensile and tearing strength results also allowed the calculation of reduction factors (RFs) for the effect (isolated and combined) of the RL and abrasion tests. As in other works [12,13,24], the reduction factors represent the quotient between the strength (tensile or tearing) of the intact sample and the respective strength of a damaged sample.…”

“…Previous research has shown that, although it is a common method, multiplying partial reduction factors may result in a misrepresentation of the combined effect of degradation agents. When inaccurate, the resulting reduction factors may either be conservative [8][9][10] or underestimate [11][12][13] the combined effect of the degradation agents.…”

“…Previous research on mechanical damage of geosynthetics promoted by exposure to repeated loading and abrasion has shown that the mechanical and hydraulic properties of these materials can be affected by damaging actions [12,13,24]. Different materials have been tested, mostly geotextiles and geogrids, with their structure having a significant influence on their survivability to damaging actions.…”