Effect of environmental temperature on bending strength of the finger jointed aspen lumber
¹Forest and Wood Products Research and Development Institute, Dobeles iela 41, LV-3001 Jelgava, Latvia
²Latvia University of Life Sciences and Technologies, Forest faculty, Department of Wood Processing, Dobeles iela 41, LV-3001 Jelgava, Latvia
³ “4 Plus” Ltd. Abula iela 6B, Valmiera, LV-4201; Merķeļa iela 20, Alūksne, LV-4301, Latvia
*Correspondence: uldis.spulle@llu.lv
Abstract:
Glued sauna wall boards are used as non-load-bearing structures. These products are subject to aggressive microclimate impact and very often for the gluing in length and width thermoplastic polyvinyl acetate adhesives (PVAC) are used.
In the performed research sauna wall boards made of common aspen (Populus tremula L.) with mean wood moisture content 8% were used. For the gluing in length with finger joint PVAC glue of D4 (LVS EN 204) group was used.
The aim of the research is identifying the impact of the environmental temperature on the strength of finger jointed aspen timber in 4 point static bending (in compliance with standard LVS EN 408). As a result of the study it was established, that after holding the finger jointed testing pieces visible in flat wise for 3 hours at the temperature of 100 oC, the mean bending strength decreased by 56% or 31.7 MPa in comparison to that held in the standard atmosphere. In case of the aspen timber with finger joints visible in edge wise held for 3 hours at the temperature of 100 oC, the bending strength decreased by 60% or 29.3 MPa in comparison to the testing pieces of the same type held in the standard atmosphere.
Key words:
sauna wall board, temperature effect, thermoplastic glue