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Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
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Title: Small scale test to measure the strength of adhesives at elevated temperatures for use in evaluating adhesives for cross-laminated timber (CLT)

Source: Wood & Fire Safety, 2020. 3-8.

Author(s)Zelinka, Samuel L.; Miyamoto, Byrne ; Bechle, Nathan J.; Rammer, Douglas

Publication Year: 2020  View PDF »

Category: Journal Articles
Associated Research Project(s):   FPL-4714-2B   FPL-4716-2A

Abstract: Cross laminated timber (CLT) is becoming widely available in North America. The product standard for North American CLT, PRG-320, has strict requirements on adhesive performance under fire scenarios. To become an adhesive certified under PRG-320, a full sized CLT compartment must be built and tested without a second flashover occurring caused by delamination. Currently, only three adhesive formulations are PRG-320 certified. This large scale test is expensive to run and only yields “pass-fail” results. In this paper we present small-scale adhesive tests performed at the Forest Products Laboratory. The tests examine a single lap shear joint. The samples are tested at elevated temperatures in a universal testing machine with an environmental chamber built around the grips. The strains are measured using digital image correlation. Tests were conducted in two different manners. In the first test, thermal equilibrium was achieved and the sample was loaded to failure. In the second test, a constant load was applied and a thermal ramp was applied until failure occurs and the temperature at failure was recorded. Importantly, the tests were compared against control samples of solid wood (no adhesive) so that adhesive strength could be normalized to that of solid wood. It is hoped that this small-scale test can aid in the understanding of CLT adhesive performance and be used to screen adhesives prior to investment in large scale adhesive qualification tests.

Keywords: Mass timber; adhesives; elevated temperatures; strength; polyurethane; creep

Publication Review Process: Formally Refereed

File size: 664 kb(s)

Date posted: 09/23/2020

This publication is also viewable on Treesearch:  view
RITS Product ID: 99401
Current FPL Scientists associated with this product (listed alphabetically)
Rammer, Douglas R.
Research General Engineer
Zelinka, Samuel L.
Materials Research Engineer
 

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