1.1 This test method covers the procedure for measuring the aperture stability modulus of a geogrid. (The terms secant aperture stability modulus, torsional rigidity modulus, in-plane shear modulus, and torsional stiffness modulus have been used in the literature to describe this same property.) 1.2 This test method is intended to determine the in-plane stability of a geogrid by clamping a center node and measuring the stiffness over an area of the geogrid. This test method is applicable for to various types of geogrid. 1.3 This test method is intended to provide characteristic properties for design. This test method was developed for pavement and subgrade improvement calibrated design methods requiring input of aperture stability modulus. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.
The aperture stability modulus was used in a couple of paved and unpaved roads design model adopted by FHWA.
Keywordsgogrids; index test; ;aboratory test; base reinforcement; subgrade improvement; torsional rgidity; aperture stability mdulus; in-plane sear modulus
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Ballot Item Approved as D7864-2015 and Pending Publication