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Physical and mechanical properties of a suitable constructional timber of Bangladesh
1997 - IRG/WP 97-40102
The study of physical and mechanical properties of lohasirish timber (Derris robusta Roxb.) grown in Bangladesh revealed that the sapwood is whitish to yellowish white, heartwood is dark grey to blackish in colour; the texture is moderately fine, the grain in mostly straight and coarse with whitish rings of parenchyma; shrinkage is moderate; the EMC ranges from 12% to 16%; fuelwood colorific value is higher; workability is moderately difficult but suitable for constructional works; the wood is heavy, the density is 750 ± 5% kg/m3 and 134% of Bangladesh teak (Tectona grandis); the sapwood is perishable and heartwood is moderately durable to durable; kiln-drying is moderately difficult to difficult; sapwood is easily pressure treatable but heartwood is refractory to treatment. The modulus of rupture (MOR) at green condition is 70 ± 2% N/mm2 which is about 100% of Bangladesh teak. The timber is very suitable for all constuctional and structural uses including electric anchor logs, crossarms and railway sleepers, beams, door frames etc.
A K Lahiry

Imprégnation de bois ronds par déplacement de sève à Madagascar
1975 - IRG/WP 352
M Fougerousse, P Guéneau

Impregnation of roundwoods by sap-displacement in Madagasca
1975 - IRG/WP 352 E
The use of roundwoods is already very important in Madagascar and steadily increasing for the following applications: - posts, electricity and telephone line supports (medium voltage) - stakes, piles for civil engineering structures, bridges, gantries, road and port works, etc. - construction of houses (posts, frameworks, piles, etc.) and rural buildings (sheds, stables, piggeries) - fence posts, vine stakes, posts for cattle pens, etc. As in all tropical, climates, the agents of destruction of standing timber are numerous and very active. Under these conditions, the natural durability of currently used species does not exceed a few years. It is necessary therefore to consider treatments for securing prolonged service life, without too much cost increase, so that users do not choose substitutes such as metal or concrete. The treatments in pressure vessels can only be applied, from an economical point of view, in regions near impregnation plants. But rural areas, too remote and badly served by transport, cannot be supplied in this way, because of the high transportation cost which has to be added to that of the treatment. This is why for a long time attention has been given to treatment processes and preservatives which can be applied without industrial equipment, at small scale sites, scattered eventually mobile. For a reasonable cost, these techniques confer to the wood a sufficient resistance to the agents of destruction, the most virulent of which are decay fungi and termites, in some cases both, depending on the area. Research in this direction has been carried out on the treatability of some Madagascan species using sap displacement.
M Fougerousse, P Guéneau

Improvement of Grevillea robusta durability using heat treatment
2006 - IRG/WP 06-40333
Heat treatment of Grevillea robusta was carried-out under inert conditions to improve its durability. Resistance of heat treated samples was evaluated by malt agar block tests after three months of exposure to several wood rotting fungi. Results showed that the fungal durability was greatly improved after treatment. There was a good correlation between fungal resistance and mass loss which is a factor of time when the treatment temperature is held constant. Microscopic, FTIR and 13C MAS NMR analysis were performed to characterize wood chemical and anatomical modifications that occur after treatment to understand the reasons of the durability improvement.
F Mburu, S Dumarçay, F Huber, M Petrissans, P Gérardin