Physico-Mechanical and Energy Properties of Pine (pinus Sylvestris) and Beech (fagus Sylvatica) Wood from Railroad Ties

The objective of the present work was to determine the physico-mechanical and energy properties of pine (Pinus sylvestris) and beech (Fagus sylvatica) wood from railroad ties. The ties were divided into internal and external parts as well as into parts impregnated and unimpregnated with creosote oil. The effects of creosote impregnation on wood hardness, compressive strength parallel to the grain, static bending strength, and calorific value were studied. The obtained results show that the parameters of the analyzed samples meet the standard requirements (EN 338) for construction wood (compressive and bending strength class: C50—pine; D70—beech). Depending on the particular property being studied, both pine and beech samples belong to the highest or one of the highest wood quality classes. Creosote oil considerably increased wood density (by 9% for beech and 19% for pine) but did not affect its hardness. Creosote impregnation significantly improved the compressive strength parallel to the grain of both wood species (beech: σc=51.99 MPa (IN); σc=57.78 MPa (OUT); pine: σc=36.56 MPa (IN); σc=42.45 MPa (OUT)); in the case of static bending strength, its value was increased for beech wood (σg=106.13 MPa (IN); σg=113.18 MPa (OUT)) and reduced for pine wood (σg=66.34 MPa (IN); σg=82.62 MPa (OUT)). The oil contained in wood from ties significantly elevated its calorific value (by 25% for beech and 10% for pine). Unfortunately, the presence of creosote oil currently prevents wood from railroad ties from being reused as the oil is deemed hazardous and carcinogenic. However, if it were possible to isolate the unimpregnated parts of railroad ties, they could be reapplied for construction or other uses.