Assessment of biodeterioration for the screening of new wood preservatives: Calculation of stiffness loss in rapid decay testing

Abstract

Abstract Demand for the development of environmentally benign wood preservatives has increased significantly. To reduce the evaluation time of prospective candidates, reliable accelerated decay methodologies are necessary for laboratory screening of potential preservatives. Ongoing research at Mississippi State University has focused upon utilizing custom built equipment to measure stiffness losses in wood wafers after 4 weeks of fungal exposure as opposed to mass losses in blocks after 12 weeks. Stiffness loss as a measure to quantify the extent of biodeterioration may allow detection of incipient decay. The resistance of untreated and treated southern yellow pine and radiata pine (Pinus radiata) sapwood wafers to biodeterioration by brown rot (Neolentinus lepideus, Gloeophyllum trabeum and Postia placenta) and white rot (Trametes versicolor and Irpex lacteus) fungi was investigated by measuring stiffness. From the data collected percentage stiffness losses were calculated based upon modulus of elasticity. It is a potentially accurate alternative to the “secant modulus” at a deformation equal to 5% of the specimen height calculation generally performed.