A proposed new ASTM International test method will be used by ready-mix concrete producers to characterize the drying behavior of new and existing concrete mixture proportions. WK37029, Test Method for Measurement of Mass Loss Versus Time for One-Dimensional Drying of Saturated Concretes, is being developed by Subcommittee C09.66 on Concrete's Resistance to Fluid Penetration, part of ASTM International Committee C09 on Concrete and Concrete Aggregates.
"This proposed standard is being developed to support the modeling of concrete service life," says Dale Bentz, chemical engineer for the Materials and Structural Systems Division in the Engineering Laboratory at the National Institute of Standards and Technology.
Bentz, the chairman of the task group developing WK37029, notes that, in many applications, concrete is exposed to wetting and drying conditions such that the concrete is partially saturated. The purpose of the proposed standard is to provide information on the mass loss versus time (drying) behavior of an initially saturated concrete specimen exposed to one-dimensional drying in a controlled temperature and relative humidity environment.
"The drying information provided by the test in WK37029 can be used to directly assess the drying propensity of a given concrete mixture," says Bentz. "This information could be valuable for industrial flooring applications where quick drying is often desirable." Bentz also notes that the data can be analyzed to provide estimates of vapor diffusivity and liquid permeability for the concrete mixture being tested.
Ready-mix concrete producers, as well as testing laboratories and concrete consultants, will be the primary users of WK37029.
Participation in the standards developing activities of C09.66 is welcome. The subcommittee would be particularly interested in working with laboratories that would be willing to implement the test method contained in WK37029, as well as anyone else who has suggestions for modifications of the current version of the proposed standard.
CONTACT Technical Information: Dale P. Bentz, National Institute of Standards and Technology • Gaithersburg, Md. • Phone: 301-975-5865 | ASTM Staff: Scott Orthey • Phone: 610-832-9730 | Upcoming Meeting: Dec. 9-11 • December Committee Week • Jacksonville, Fla.