Ultrasound classification for recycled glulam sleepers

Nowadays, due to environmental concerns and high market value, the railroads dramatically decreased the use of native timber sleepers. Aiming to reducing environmental impact, a recycling process was developed where wooden sleepers that are discarded or sold at low prices by railway companies are transformed into glulam railway sleepers. Vale Company donated 46 railway sleepers for this study, which 35 of these were transformed into 6 new railway sleepers. In this article, the non-destructive tests on discarded railway sleepers and on the thin board's procedures are described. These tests were performed in order to determine the greater longitudinal moduli of elasticity for the upper and lower boards’ distribution of the recycled glulam sleepers (RGS) and also for determining the direction of lamination of the sleepers, to provide a greater reuse of materials. The results indicated that the railway sleepers ultrasound test are not indicated and should be replaced by testing only one board of each sleeper, which is sufficient to classify the pieces.