A proposed new ASTM standard will provide proper direction and ensure adequate documentation to aid in the interpretation, understanding and reduction of variance in test results for fiber-reinforced concrete.
WK35250, Practice for Fiber-Reinforced Concrete for Making and Curing Test Specimens in the Laboratory and Field, is now being developed by Subcommittee C09.42 on Fiber-Reinforced Concrete, part of ASTM Committee C09 on Concrete and Concrete Aggregates.
“Fiber-reinforced concrete is not the same as ordinary Portland cement concrete in terms of simple fabrication,” says Clifford MacDonald, fellow, American Concrete Institute, director of engineering, FORTA Corp., and chairman of the task group developing WK35250. “There are specific issues that need to be addressed to ensure consistency in making specimens for testing. At this time, there are limited and/or inconsistent practices instructing the industry on how to make FRC specimens.”
MacDonald also notes that current standards for other types of concrete test samples involve rodding or internal vibration, both methods that can lead to nonuniform fiber concrete. Both of these conditions increase variance between test results.
WK35250 describes testing done by means of external vibration, which is effective for fiber-reinforced concrete. Testing agencies and those who specify testing of fiber concrete will use the proposed standard, once it has been approved. Fibers can be used in any concrete, and particularly fiber reinforced concrete is used in precast applications, industrial floor slabs, composite metal decks, blast containment structures, overlays, tunnels and many other applications.
All interested parties are invited to participate in the development of WK35250.
CONTACT Technical Information: Clifford MacDonald, FORTA Corp. • Inver Grove Heights, Minn. • Phone: 651-552-5963 O ASTM Staff: Scott Orthey • Phone: 610-832-9730 O Upcoming Meeting: June 24-27 • June Committee Week • San Diego, Calif.
This article appears in the issue of Standardization News.