Lei Han, Dr. Mohammad Derikvand, Dr. Matthew Schwarzkopf and Dr. Andreja Kutnar, InnoRenew CoE, UP IAM researchers, together with Dr. Alexander Scharf from Norwegian Institute of Bioeconomy Research (NIBIO), Bogdan Mitkovski from PROFILES d.o.o. and Dr. Dick Sandberg from Norwegian University of Science and Technology (NTNU), recently published a new scientific article “Moisture-activated set-recovery of thermo-hydro-mechanically densified hardwood dowels for high-tolerance timber connections” in Construction and Building Materials journal.

In the article they investigate thermo-hydro-mechanically (THM) densified hardwood dowels for timber construction. Unlike traditional dowels, which require tight press-fits, these densified dowels expand when exposed to moisture, creating a self-tightening connection without glue or metal fasteners. European beech performed best, generating high pressure and retaining strength, while poplar expanded more but with lower force. Radial densification was more effective than tangential and hot water triggered faster expansion. This approach allows easier assembly, high tolerance in holes and predictable, durable connections, offering a promising solution for sustainable timber construction.