By Bob Mackey
ASTM Committee D35 on Geosynthetics
The ASTM Committee D35 on Geosynthetics met in New Orleans, La., Jan. 28–30, 2015. There was significant progress within several of the D35 subcommittees as noted here:
Subcommittee D35.03 on Permeability and Filtration
The issue that generated a great deal of discussion at the January meeting of D35.03 centered around the use of the results from the Pore Size Distribution Test (D6767) to calculate apparent opening size and permittivity. The main item of discussion was the shape factor used in the calculations. Two proposed standards were discussed: (1) specification for catch basin inlet filters and (2) geocomposite drainage guide.
Subcommittee D35.05 on Geosynthetics in Erosion and Sediment Control
Joel Sprague is now chair of this subcommittee. It is focusing on developing standards associated with defining and measuring relevant material properties and appropriately incorporating them into material specifications associated with erosion and sediment control applications.
D35.05 has set up task groups to focus on improving the sampling and sample preparation procedures as well as Precision and Bias statements in all the current index tests for rolled erosion control products (RECPs).
Other subcommittee initiatives include the development of index tests for characterizing geosynthetic concrete composite mats (GCCM), a specification for turf reinforcement mats (TRMs), a new test method for horizontal permeability of sediment retention devices (SRDs), and a new test method for determining functional longevity of RECPs and SRDs.
Subcommittee D35.10 on Geomembranes
Subcommittee D35.10 continued discussions regarding leak location testing, with four revised standards, one still going through the ballot process and one new one on conductive-backed geomembranes to be started.
With the passing of a new standard practice on the MQC of thermal factory geomembrane seams, the subcommittee will soon start work on a CQC practice for destructive testing of field thermofusion seams. D3745 on the installation of bituminous geomembranes was brought over to D35.10 from D08.20. The subcommittee will start work on updating this standard.
Bob Mackey, principal engineer at S2L Inc. in Maitland, Fla., is the immediate past president of the North American Geosynthetics Society (NAGS). He is also chairman of the ASTM Committee D35 on Geosynthetics and is a member of Geosynthetics magazine’s Editorial Advisory Committee.