" LIGNOCELLULOSIC A1ATERIAL IN BUILDING ELEMENTS "

Abstract

Modem building techniques as cemented lignocellulosic bricks are applied for some general aspects such as satisfying the increasing population, avoiding some environmental pollution and economising consumption of natural resources.

The major study in this work is carried out on spruce wood waste to improve its water repellency and to define the optimum conditions used to produce cemented lignocellulosic bricks possessing low bulk d nsity, high water repellency and moderated strength propOerties. These optimum conditions are applied on the non-wood fibrous materials, such as bagasse and barked cotton stalk.

Generally, using different concentrations of synthetic resins improved the water resistance (W.R.V. decreased) of wood waste. The extent of improvement increased with increasing resin concentration; up to 40 % and 50 % in case of urea - formaldehyde and novolac resin, respectively. At relatively low resin concentration (especially 10 %) the improvement in water resistance is time dependant while it is the reverse (time independant) at relatively high resin concentration (especially 50%). On the other hand, at relatively higher resin concentration (50 %) the impregnation of wood with alcoholic novolac resin produces high water resistance than urea­ formaldehyde ( the percent of improvement based on untreated sample are 47.63 %, 36.10 % respectively). Results also showed that the maximum improvement percentage in case of urea-formaldehyde (40% concentration) and novolac (50 % concentration) is nearly the same 46.24 %, 47.63 %, respectively.