抄録
Natural penetration of water into wood specimens was investigated by using soft X-ray densitometry. This method makes it possible to obtain the continuos moisture distribution within the specimen during water penetration without destruction.
Specimens were taken from the sap- and heartwood of Hinoki (Chamaecyparis obtusa Endl.) and the sapwood of Akamatsu (Pinus densiflora Sieb. et Zucc.), and trimmed to the dimension of 10mm (R)×10mm(T)×180mm(L) and 10mm(R)×2mm(T)×180mm(L). One end of each specimen was dipped in distilled water and the water uptake was measured continuously by a load cell. At given time intervals, the specimens were taken out to weigh water uptake and for soft X-ray irradiation. After these measurements, the specimens were put back to continue the water penetration. The X-ray film obtained was scanned both in L- and R-direction of the specimens by a densitometer. Moisture increase within the specimen was calculated from the difference of film densities before and after penetration. As a result, the changes in moisture distribution in L- and R-directions of the specimen and penetration height during the process were clarified. With the aim to make clear the path of water penetration, wood specimens were stained with 1% aqueous solution of acid fuchsine, and the split radial surface was observed under a stereoscopic microscope.
It was concluded that the moisture distribution in each direction of the specimen was characteristic of the wood species. This characteristic was considered to be caused by the difference in penetration mechanism due to wood structure.
