This Technical Note 3 focusses on the importance of using ASTM D8058 for determining the flexural strength of GCCMs.
ASTM D8058 GCCM Flexural Strength:
GCCMs behave as composite materials, they combine the benefits of geosynthetics and concrete. Broadly speaking, conventional geosynthetics are strong in tension and weak in compression, whereas concrete is strong in compression but weak in tension.
Flexural Strength testing of cured GCCMs provides the best overall indication of the in-service performance of a GCCM by compressing one surface while simultaneously extending the other and is considered the standard index test for this class of material.
The internationally recognised standard for flexural strength testing of GCCMs is ASTM D8058 ‘Standard Test Method for Determining the Flexural Strength of a GCCM Using the Three-Point Bending Test’.
What is ASTM D8058:
ASTM D8058 uses a constant rate of extension testing machine with a 3-point fixture set up to continuously measure the stress and displacement of a cured GCCM specimen as it is loaded to failure. By studying the results, ASTM D8058 enables the composite performance of a GCCM to be understood by determining both the Initial Flexural Strength (IFS), which is governed by the cementitious material, and the Final Flexural Strength (FFS), when the geosynthetic components fail.