Primary Study on Compressed Preservative-treated Wood (CPW) for Outdoor Applications
Jinzhen Cao, Jia Mao
In this study, the compressed wood samples pre-treated with hot water bath or water spraying were immersed in the ammoniacal copper quat –type D (ACQ-D) preservative solution to get compressed preservative-treated wood (CPW). The liquid absorption and the recovery rate of compression deformation of the compressed wood was determined, as well as the surface hardness, the distribution of density and CuO retention in the thickness direction of CPW. The results showed that: (1) the recovery rate and liquid absorption were closely related with each other. Generally a higher recovery rate of compressed deformation corresponded to a higher liquid absorption; (2) the liquid absorption of compressed wood with pre-treatments was about 1.5 times of the untreated control samples, and the surface hardness of the CWP prepared with this method was 3~4 times of that of the untreated control samples; while the corresponding values of those without pre-treatments were more than 2.0 times and about 1.6 times, respectively; (3) the density distribution of the CWP with pre-treatments were much more uniform in the thickness direction, additionally the retention of CuO appeared to be much higher and had a clear trend of higher retention on surfaces and lower inside compared with that of the CWP without pre-treatments. In conclusion, the CPW prepared in this study can achieve both surface densification and preservation, which are suitable for outdoor applications.