Wood construction materials like plywood or laminated veneer lumber rely on adhesives for part of their structural integrity. When used in outdoor applications, however, humidity can affect their performance even when the materials are mostly protected from the elements.
FPL researcher Joseph Jakes is taking a closer look at the relationship between moisture, adhesives, and wood, particularly as it relates to historic covered bridges. The roof structures keep the heavy timber trusses dry enough that they have lasted 100 to 200 years. But when historic bridges are repaired using today’s engineered wood products, the swelling and shrinking of wood due to humidity changes can cause wood-adhesive bondline failures that result in further costly repairs.
Jakes is working to develop new, sophisticated techniques to better understand the interactions between wood and adhesives at the cellular level. These techniques can be used to formulate improved adhesives, resulting in more cost-effective methods for preserving historic covered bridges.
The results of this project reach beyond the benefits of historic bridge applications. The development of more durable engineered wood products promotes the forest products industry as a whole by increasing the use of wood in outdoor applications. This study will also add to greater fundamental understanding of how wood cell walls swell with moisture.