Fuktgenomträngning i korslimmat trä : experimentell studie av limskiktets roll

Sammanfattning

Cross-laminated timber (CLT) is a sustainable construction material increasingly used in structural applications. However, its hygroscopic nature makes it sensitive to moisture, particularly during the construction phase. This study investigates how adhesive layers in CLT influence moisture transport across the element's cross section, focusing on capillary water uptake. Laboratory experiments were conducted with both CLT and solid wood specimens exposed to continous water contact for 25 days. Moisture content was measured at different depths using a hammer electrode and validated through the oven-drying method according to EN 13183-1. The test spicimens featured one or more polyurethane (PUR) adhesive layers. The results show that moisture accumulation was significantly lower above adhesive layers, indicating that the glue acts as a partial barrier to vertical capillary transport. In contrast, moisture distribution in solid wood was more uniform. This effect was especially evident in CLT specimens with multiple adhesive layers. Comparisons of measurement methods showed high consistency, supporting the reliability of the results. These findings suggest that adhesive layers have a clear impact on moisture dynamics and should be carefully considered in the design and construction of moisture-sensitive timber systems. Keywords: cross-laminated timber, moisture transport, adhesive layers, moisure content, capillary absorption, hammar electrode