Corrigendum to “Mechanical characterization of novel Homogeneous Beech and hybrid Beech-Corsican Pine thin Cross-Laminated timber panels” [Constr. Build. Mater. 271 (2021) 121589] (Construction and Building Materials (2021) 271, (S0950061820335935), (10.1016/j.conbuildmat.2020.121589))

Abstract

For a mistake in writing the last versions of the above papers, the article “Mechanical characterization of novel Homogeneous Beech and hybrid Beech-Corsican Pine thin Cross-Laminated timber panels”, two authors were missing who provided the machine grading of beech and corsican pine baords and the regression analysis for the estimation of the mechanical properties of the boards from the non-destructive tests. So the authors of the article are: Authors: Martina Sciomentaa, Luca Speraa, Chiara Bedonb, Vincenzo Rinaldia, Michela Nocettic, Michele Brunettic, Massimo Fragiacomoa, Manuela Romagnolid aDepartment of Civil, Architecture and Building and Environmental Engineering, University of L'Aquila, Via Giovanni Gronchi 18, 67100 L'Aquila, Italy bDepartment of Engineering and Architecture, University of Trieste, Via Alfonso Valerio, 6/1, 34127 Trieste, Italy cCNR-IBE, Institute of BioEconomy, Via Madonna del Piano 10, 50019 Sesto Fiorentino, FI, Italy dDepartment of Innovation of Biological, Food and Forestry Systems (DIBAF), University of Tuscia, Via S. Camillo de Lellis, 01100 Viterbo, Italy Moreover, the authors regret that some parts of the paragraph 2.1 need small revisions and it should be replaced with the text below. The three-layered CLT panels object of study were produced by using softwood: Corsican pine (Pinus nigra subsp. laricio) and hardwood: beech (Fagus sylvatica L.) originated from a Southern Italy (Calabria) forest. Raw material was cut into boards having a nominal section of 120 mm width and 20 mm thick. Beech boards had an average length of 3.10 m while the Corsican pine ones of 4.00 m. A batch of 597 beech and 220 Corsican pine boards was collected and kiln-dried to a moisture content of 10%, in order to satisfy the manufacturers requirement for gluing process. The boards were strength graded according to EN 14081-2 rules [14] by the grading machine ViSCAN-Portable (MiCROTEC). Each board was first weighted and measured to determine its density ρ. Then, the natural frequency of vibration f1 induced by a percussion was measured by using a laser interferometer. The dynamic modulus of elasticity E0,dyn was thus calculated as: [Figure presented] where ρ is the density of the board, l is the length and f1 is the frequency. The machine settings used for the strength grading of the boards of both beech and pine were developed in previous studies [11],[15]. The strength class combinations used to qualify the raw material were D40 and rejects for beech and C20 and rejects for pine (EN 338 [16]). The 95% of beech boards was classified as D40, while 5% of the samples was discarded because of defects (presence of fiber deviations and not uniform planing). In the case of Corsican pine boards, the 73% of them was graded as C20, while the remaining 27% was rejected. A total amount of 365 beech boards and 90 Corsican pine boards was hence used for manufacturing a series of CLT panels. Regression analysis was performed based on destructive tests carried out on beech and pine raw material for the machine setting development [11],[15]. Linear regression were used for the estimation of the Modulus of Rupture (MOR), as well as the global and local Modulus of Elasticity (MOEglobal and MOElocal respectively) from the dynamic modulus of elasticity measured during machine grading. The mean properties obtained by the grading procedure and the evaluated MOR and MOEs are summarized in Table 1. For the research study herein discussed, two different types of adhesives were used, namely a melamine Urea Formaldheyde (MUF) adhesive (GripProTM Design – AkzoNobel, that was obtained by mixing a two component hardner (H002) and a liquid flexible resin (A002)), and a one-component Polyurethane adhesive (Loctite ® HBS 049-Purbond). The choice of employing the melamine adhesive was due to the usage of beech hardwood boards in panel's homogeneous and hybrid configurations with Corsican pine's boards. The GripProTM adhesive is specifically designed for softwood, as well as for hardwood timber, such as beech, birch, oak and chestnut. The development of machine setting for black pine was performed in the frame of the A.Pro.Fo.Mo.project, financed by GALStart, (Leader m. 124, PSR 2007-2013 Toscana Region). The financial support is gratefully acknowledged.