A new ASTM International standard will aid engineers and specifiers looking to understand the quality and strength of cement contained in geosynthetic cementitious composite mats (GCCMs). ASTM’s geosynthetics committee developed the new standard, which is needed to allow for a consistent industry method for the application of compression strength in GCCMs.
GCCMs are flexible, concrete-impregnated fabrics that harden on hydration to form a thin, durable waterproof and fire-resistant concrete layer.
According to ASTM International member Joe Royer, vice president of research and development, ClockSpring NRI, the new standard (soon to be published as D8329) will be critical for manufacturers’ ability to compare cement quality in their products. He notes it will also be important to asset owners, engineers and contractors to ensure that compression data reported on GCCM technical data sheets are measured for field-applicable water-to-cementitious material ratios.
“Because these materials are hydrated in the field typically with excess water and no mixing, it is critical to understand the actual field water-to-cementitious material ratio,” says Royer. “If a measurement is taken with an optimized value from lab conditions it will not accurately reflect what is occurring in the field application, so this standard allows for laboratory determination of typical field ratios.”
Royer notes that task groups within the geosynthetics committee are developing other GCCM-related standards, covering flex, installation and sampling, along with a GCCM terminology standard. Become a member at www.astm.org/JOIN.