Characterization of Dowelled Cross-Laminated Timber Panels Made of Uruguayan Fast-Grown Species

In recent decades, the development of adhesive-free engineered timber products has become one of the primary research areas in timber construction systems. This paper studies the structural behaviour of Dowelled Cross-Laminated Timber (DCLT) panels made of Uruguayan fast-growing Pinus taeda , connected by hardwood dowels. Two series, each comprising three structural-size panels were constructed using C14 and C22 classes timber, joined by 20 mm Eucalyptus grandis dowels. Shear tests on dowelled-cross connections and four-point bending tests on DCLT panels were performed, and the slip modulus and bending properties, respectively, were obtained. Results indicated that DCLT-C22 panels showed significantly higher bending strength (16.1 MPa) and stiffness (3,091 MPa) values than DCLT-C14 panels (10.7 MPa; 2,228 MPa), suggesting that the quality of lamellae had influence on the panel’s structural properties. The typical failure mode occurred under tension exclusively in the bottom lamellae, with fractures attributed to the presence of knots along the drilled holes and near the load application area. Wooden dowels exhibited minor visible fractures and crushing along their length. These findings suggest that adhesive-free cross-laminated timber panels made from Uruguayan pine are a promising alternative for residential floors and roof uses, advancing more sustainable construction systems.