Treatability of US wood species with pigment-emulsified creosote

Since the 1920s, creosote has been used extensively in the United States fo r treatment of construction timbers, poles, and posts. However, creosote ha s the tendency to exude or "bleed" from some treated commodities, producing a tar-like covered surface. In the United States, creosote-treated product s exhibiting cleaner dried surfaces and a reduced tendency to bleed have be en achieved through reduction of the xylene-insoluble carbonaceous fraction in creosote. In Australia, pigment-stabilized creosote emulsion formulatio ns have been designed and developed to "lock" the oil phase within the trea ted timber and are referred to as pigment-emulsified creosote (PEG). The su rfaces of PEG-treated commodities remain dry; the creosote does not leach i nto the ground or water in marine environments; and the oil remains mobile within the microstructure of the PEG-treated products. In this study, the t reatment characteristics of southern pine, red oak, red maple, and Douglas- fir with PEG 30W are reported. Results showed that treatment of the four wo od species with PEG 30W is generally comparable to treatment with reference creosote P1/P13, except that slightly greater variability in creosote load ing occurs with PEC.