Improving ductility and bending features of poplar glued laminated beams by means of embedded carbon material

Abstract

Timber from fast-growing plantations such as poplar, typically used for plywood, can play a very important role in the coming decades for the development of a bio-economy. Long-term decarbonization in the construction sector depends to a considerable extent on the development of new engineered wood products for structural use. Composite materials resulting from the combination of materials with low mechanical properties (poplar timber) and materials with high mechanical properties in low proportions (carbon composites) stand as a good technological solution, in that they can provide low-weight products with competitive mechanical properties. This paper describes an experimental campaign involving glued laminated beams made of poplar timber and carbon composite material. Two types of carbon composites (fabric and pultruded laminated), thickness and location (at tension, compression or both sides) are studied in terms of ductility, stiffness and strength of the whole element by means of bending and non-destructive tests. The results demonstrate that the position and the type of reinforcement along the cross-section bear a clear influence on the mechanical behavior of the whole element. In terms of stiffness and strength, respective improvements of up to 44% and 33% are achieved. Moreover, high ductility values are obtained when the reinforcement is placed at the tension area, whereas brittle behavior is observed when the reinforcement is placed only at the compression zone.