ISO 13431 pdf download.Geotextiles and geotextile-related products — Determination of tensile creep and creep rupture behaviour
1 Scope
This Standard specifies a method for determining the tensile creep and creep rupture behaviour of geotextiles and geotextile-related products in an unconfined situation. Application of this standard is limited to those products and applications where the risk of collapse of a structure due to premature failure or to strain/time variation of the reinforcement under constant load is of essential importance. As the test is carried out over a long period of time and the procedure is complex, it is therefore recommended that the test is not considered to be a routine quality control test. The results of the test may not be representative of the performance of the products when subject to soil pressures.
2 Normative References
This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate points in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies.
3 Definitions
For the purposes of this standard the following definitions apply: 3.1 tensile strength: Maximum load per unit width, in kilonewtons per metre, developed in a specific material subjected to an external tensile load, when measured in accordance with EN ISO 10319.3.2 preload: Force, in kilonewtons per metre, equal to 1 % of the tensile strength, but not more than 10% of the tensile creep load, applied to the specimen to enable the gauge length and strain zero to be determined under reproducible conditions. 3.3 nominal gauge length: Initial distance between two reference points located on the specimen parallel to the applied load before the application of the preload. The gauge length should be set to be completely clear from the clamping devices. The gauge length should be a representative part of the specimen, e.g. for grid structures the gauge length should be a whole number of meshes or ribs. 3.4 technically representative width (TRW): A small width, that exhibits tensile strength/ strain characteristics per unit width, under identical test conditions, within ± 5% for tensile strength and ± 20% for strain at the maximum load, of the values measured in accordance with EN ISO1 0319. 3.5 tensile creep strain: Time dependent change in tensile strain of a specimen subject to a constant tensile load. 3.6 tensile creep rupture: Tensile failure of a specimen subject to a constant tensile load, which is less than the tensile strength. NOTE: In some materials tensile creep rupture is preceeded by an increasing rate of strain. 3.7 tensile creep load: Constant tensile static load per unit width, in kilonewtons per metre, applied to the specimen. NOTE: The tensile creep load is usually expressed as a percentage of the tensile strength of the sample. The tensile creep load includes the preload and, if applicable, any load due to the loading device.3.8 loading time: Time, in seconds, required to apply the full tensile creep load. 3.9 creep time: Time elapsed from the end of the loading time. 3.10 time to creep rupture: Time elapsed from the end of the loading time until tensile creep rupture of the specimen. 3.11 initial strain: Change in the gauge length (strain), in percent, measured on the specimen at (60 ± 5) s after the end of the loading time. 3.12 lateral contraction: Decrease in the width of the specimen during the tensile test, expressed as a percentage of the width of the specimen under preload, measured at the centre of the gauge length (see figure 2).