Aimed at helping specifiers and engineers, a new ASTM International standard addresses the quality and strength of cement contained in geosynthetic cementitious composite mats (GCCMs), which are flexible concrete impregnated fabrics that harden on hydration to form a thin, durable waterproof and fire-resistant concrete layer. 

 
ASTM's geosynthetics committee developed the new standard to allow for a consistent industry method for the application of compression strength in GCCMs. 
 
According to ASTM International member Joe Royer, vice president, R&D, 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," Royer states. "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.
 
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