Abstract
We manufactured glulams with wood preservative (ACQ, AZP) treated and untreated laminae using two adhesive resins (PRF and API), and conducted aging treatments as follows.: (1) 10 years outdoor exposure of glulams, (2) 2 years outdoor exposure of block-shear-form pieces of 10mm and 25 mm width sawn from glulams, and (3) 1∼20 cycles of vacuum-pressure treatment of 25mm wide block-shear-form pieces. We conducted block-shear-tests after aging treatments, and goodness-of-fit tests of shear strength to distribution forms were performed. As a result for (3), no tendencies were recognized as to fits of distribution forms, and for (1) and (2), it was suggested that some specimens tend to fit the 2P or 3P Weibull distribution. We investigated the rate of decline of shear strength from the slope of the liner regression line obtained from a plot of square root of exposure month or cycles as x axis and ratio to initial average shear strength as y axis. For ACQ treated specimens, a difference of rate of decline was observed among (1)∼(3). For AZP treated and untreated specimens in (2), only slight differences between slope values were found due to width of specimen, and in (3), slope values obtained from the west side of glulams without exterior finish were nearly 0.
