Performance of CCB (Copper-Chromium-Boron) and Creosote Treated Fence Posts after 18 Years of Exposure in Greece

Abstract

The effect of 18 years exposure on toughness of Copper-Chromium-Boron (CCB) and creosote combination treated pine was examined. Fence posts were vacuum treated with CCB and subsequently at their lowest part that would lie in ground contact, with creosote using the open hot and cold tank process. After 18 years exposure under warm dry temperate climatic conditions in Greece, samples were taken from three different zones of posts: top, middle and ground contact line and tested for toughness using a Denison single blow impact bending test machine. There was no significant reduction of toughness in any of these zones. Chemical analysis of the residual CCB of unexposed and exposed samples by Inductively Coupled Plasma (ICP) showed that copper and chromium losses were insignificant but boron losses were significant being more than 50% of the initial. This was attributed to an effect of the creosote treatment. The results of this study show that climatic conditions of the exposure site play an important role. The climate is wetter and more favourable for decay in Northern Europe while in Southern Europe decay may be slower. Adequate protection may be achieved by less rigorous methods.