In [1] wurde erstmals die Herstellung eines tragenden Querschnitts in einem thermo-hygro-mechanischen Verfahren vorgestellt. Grundlage hierfür ist die Betrachtung des Holzes als zellulärer Polymerwerkstoff. Der Porenanteil von Holz, der durch die Lumen der Zellen gebildet wird, beträgt für heimische Holzarten mehr als 50 % [2]. Die chemische Zusammensetzung aus Zellulose, Hemizellulose und Lignin ermöglicht bei Wärme und Feuchtigkeit eine Erweichung [3], sodass Holz quer zur Faser auf die Hälfte seines Volumens verdichtet werden kann [4]. Dieser Vorgang geht mit Faltungen der Zellwände einher, die bei geeignetem Prozessregime hinsichtlich Temperatur, Feuchtigkeit und Verdichtungsgeschwindigkeit nahezu schadensfrei und reversibel sind. Dem verdichteten Material steht damit zur Umformung eine Dehnung von 100 % zur Verfügung [5].
Compressed laminated wood for the strengthening of glued laminated timber Glued laminated timber girders were investigated, which were strengthened with compressed laminated wood at the tension lamella and optionally also at the compression lamella to increase load-bearing capacity and stiffness. Compressed laminated wood is a wood composite consisting of beech (Fagus sylvatica) veneers, which are impregnated with phenol-resorcin resin. Compressed laminated wood possesses a YOUNG's modulus of more than 20 000 N/mm 2 and a bending strength of more than 200 N/mm 2 , which is compared to glued laminated timber GL24h a doubling and a tripling, respectively. The strengthening of the GL24h girders with compressed laminated wood led to a doubling of the bending capacity and to an increase of stiffness of about one third compared to plain GL24h girders with the same cross section. Moreover, the joint of glued laminated timber and compressed laminated wood was exposed to wetting-drying cycles to investigate the durability. Partly impregnated compressed laminated wood absorbed a lot of moisture and swelled heavily, but still less than plain beech wood. Thus, this material is only recommendable for the service classes 1 and 2. Completely impregnated compressed laminated wood showed only very low moisture uptake and swelling and can be applied also in service class 3.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.