Abstract
Needle penetration resistance (NPR) and screw withdrawal resistance (SWR) are widely used techniques for density estimation of woods integrated in timber structures. The moisture content (MC) influences these measurements and correction coefficients are needed to ensure the accuracy of results. The goal of the present paper was to scrutinize the relation between NPR and SWR measurements and MC in case of radiata pine, Scots pine, Salzmann pine, and maritime pine usually used in wood constructions, from which 25 specimens from each species were probed. The specimen’s MC ranged from 65.1 to 8.3%. Results show that NPR depth has a positive linear relationship with MC while the SWR force a negative one below the fiber saturation point (FSP). Above the FSP, the MC influence is less pronounced and less regular. MC correction factors of measurements below the FSP are proposed for the species studied.
Acknowledgments
Ministerio de Economía y Competitividad [Spanish Ministry of Economy and Competitiveness]. Plan Estatal de Investigación Científica, Técnica y de Innovación, 2013-2016, Programa de Fomento de la Investigación Científica y Técnica de Excelencia, Subprograma de Generación del Conocimiento, Proyecto: BIA2014-55089-P. Plan Nacional I+D+i 2008-2011. Proy.: BIA 2010-18858. The authors would like to thank D. Ramón García Lombardero for his helpful technical assistance in the INIA-CIFOR Timber Structural Laboratory, Spain.
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Employment or leadership: None declared.
Honorarium: None declared.
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