Untersuchungen zum System Holz-Zement

Wood-cement-composite behaviour of beech circular hollow sections

“…Beech LVL-hollow sections permanently exposed to an alkaline medium due to the subsoil installation and the cement embedment of the nails, reveal a considerable loss of material strength due to the alkaline degradation of wood (Glaus et al 1999;Hirschmüller et al 2018b;Knill and Kennedy 2003;Mašura 1982;Tamburini 1970). Extracted organic wood components, in particular beech, have a high amount of water-soluble sugars and therefore, reveal an inhibiting effect on the cement hydration, resulting in a retarded reaction time, having a reduced maximum hydration temperature (Wei et al 2000b) and a lower strength of hardened cement paste (Schubert et al 1990a). Research in the field of wood/cement interaction has shown that cement composition (e.g., use of low-alkali cements), usage of cement admixtures (e.g., chemical cement setting accelerators) and pre-treatment of wood (e.g., steaming, hydro extraction, sodium hydroxide extraction or cement micro coating) help to compensate the abovementioned cement hydration inhibiting effect (Klatt 2012;Schubert et al 1990aSchubert et al , 1990bSchwarz and Simatupang 1984;Simatupang 1986;Wei et al 2000a).…”

“…Firstly, the paper introduces the investigated composite's cross section and the associated surface modification process of the LVL hollow sections. As in published research work, mainly the maximum cement hydration temperature, its temporal position and the compressive strength of hardened cement samples mixed with wood eluate water or wood chips are of interest (Schubert et al 1990a, b;Schwarz and Simatupang 1984), only little information about the hydration inhibiting effect of wooden boards with cement contact, examined by a determination of loose cement material remaining on the contact surface, is available (Simatupang 1986). However, to the authors' knowledge, no publication deals with the surface soundness determination of cement in contact with peeled beech veneer.…”