In the past, the only measurement used to determine whether sealants could endure a great deal of foot traffic was hardness. Because research presented at symposia and from the field has shown that other factors need to be considered in the design and use of traffic sealants, ASTM International Committee C24 on Building Seals and Sealants has a new proposed standard that encompasses a wider range of factors. The document, WK6999, Specification for Horizontal Joint Seals Used in Pedestrian Walkways, is under the jurisdiction of Subcommittee C24.10 on Specifications, Guides and Practices. The committee hopes to bring the proposed standard to ballot in December 2006.

WK6999 will quantify wet applied horizontal joint sealants based on the following factors:

o Weatherability;

o Movement capability;

o Puncture resistance;

o Compression deflection;

o Resistance to dynamic loads;

o Adhesion through immersion and movement;

o Resistance to chemicals;

o Tear resistance;

o Abrasion resistance; and

o Rheology at application.

Incorporating these factors will give system designers greater flexibility in creating joints that will be ideally suited for specific situations. "There is no single product that does everything in horizontal seals today," says Larry Carbary, associate industry scientist, Dow Corning Corporation. "The proposed new standard will allow materials to have ratings according to what they are capable of performing and it will allow the specifier to design a system that can perform up to expectations."

"Committee C24 is writing the standard, but we are interested in greater participation, particularly from members of Committee E06 on Performance of Buildings," says Carbary. "Also, assistance is needed to write test methods and perform round robin testing within the next two years, so that a meaningful specification can be developed."

For further technical information, contact Larry Carbary, Dow Corning, Midland, Mich. (phone: 989/496-8696; l.carbary@dowcorning.com). Committee C24 meets June 12-16, in Reno, Nev. For membership or meeting details, contact Scott Orthey, ASTM International (phone: 610/832-9730; sorthey@astm.org).

Release #7089