|Concrete and Concrete Aggregates Committee Seeking Participation in New Bondbreaker Standard
Tilt-up construction has gained prominence over the last three decades as a practical and cost-effective method for building warehouses, offices, schools, homes and other structures. Liquid-applied bondbreakers are especially important to the tilt-up construction process for a number of reasons, but there is not currently a standard for their use in this type of construction. However, Committee C09 on Concrete and Concrete Aggregates is now working on the first, a draft Specification for Liquid-Applied Bondbreakers Used in Concrete Tilt-Up and Lift-Slab Construction. The committee is seeking participation of all interested parties familiar with tilt-up or lift-slab construction in the development of this standard.
The proposed standard will serve many purposes, says Michael A. Linn, president, Nox-Crete Products Group and a member of the C09.22 Subcommittee on Materials Applied to New Concrete Surfaces that is currently working on the standard. The primary purpose will be to clear up existing confusion and misconceptions by defining the performance differences between the various types of bondbreakers currently available.
One of the specific issues to be covered in the new standard is bondbreaker compatibility, or lack thereof, with other previously and subsequently applied products, such as curing compounds, flooring materials, exterior wall patching materials, sealers and coatings.
The standard will also cover the dual purpose that some bondbreakers have as a curing compound. Bondbreakers are commonly used to cure casting bed areas of a floor slab, as well as the entire floor slab itself and the backside of wall panels, although there is not currently a standard with which to measure bondbreakers by their curing properties.
In addition to these issues, the subcommittee also plans to address areas of concern such as emulsion stability of water-based products, resistance to settling during storage, applied-film dry time, resistance to rain wash-off and resistance to the osmotic effect.
Linn says that some of the benefits of the proposed standard include lowering construction costs, reducing product liability claims, increasing quality and enhancing the overall value of the project. He adds that design professionals, contractors, owners and manufacturers who are involved in tilt-up or lift slab construction will all benefit from the standard.
For further technical information, contact Michael A. Linn, Nox-Crete Products Group, Inc., Omaha, Neb. (phone: 402/341-1976). Committee C09 meets June 13-16 during the June Committee Week in Kansas City, Mo. For membership or meeting details, contact Jim Olshefsky, ASTM International (phone: 610/832-9714). //
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