Swelling pressure of wood determined from hygro-mechanical creep measurements

Swelling pressure in longitudinal direction has been determined on the basis of the time dependence of intensity of hygro-mechanical creep on the stretching, by the method of Moliński and Raczkowski [11]. The external stress needed for total inhibition of unidirectional spruce wood longitudinal swelling has been established. The maximum value of the swelling pressure determined on the basis of hygro-mechanical deformations of spruce wood samples simultaneously subjected to stretching in longitudinal direction and moistening is 14.4 MPa which is by 60% higher than the corresponding value found by the direct method of swelling inhibition for spruce wood sample of the same density.