Effects of moisture content on strength of CCA-treated lumber

Recent studies on the effects of chromated copper arsenate (CCA) treatment on lumber design properties have primarily evaluated the effects of such treatment at or near 12 % moisture content and at failure times of 1 to 10 min. The influence of various moisture contents and faster loading rates is unknown. This report discusses the influence of moisture content and its interaction with time-to-failure on the bending strength of CCA-treated (0.4 lb/ft 3 (6.4 kg/m 3)) lumber. The factors studied were moisture contents of 10, 15, and ≥23 % (green lumber) and ramp-load failure times in bending of 3-6, 30-60, and 300-600 seconds. This research concluded that a revised wet-use service factor for No. 1 and better waterborne-preservative-treated lumber is needed