The effect of glass fiber reinforced polymer (GFRP) on the technical properties of LSL made from poplar (Populus deltoids L.) employing pMDI and UF as binders was investigated. Technical properties such as modulus of rupture (MOR), Modulus of elasticity (MOE), shear strength (SS), compression strength parallel to the grains (CS //), impact strength (IS), water absorption (WA) and thickness swelling (TS) were determined. Results confirmed that resin type and GFRP have significant effects on the LSL properties. It was revealed that the most beneficial effect of GFRP is on MOR, MOE, IS, SS and CS respectively. The Highest properties were obtained by using pMDI as the resin and GFRP as the reinforcement, where properties such as MOR, MOE, IS, SS and CS were improved by 123, 114, 100, 94, and 90%, respectively, compared to control samples. Furthermore, GFRP incorporation led to alteration of fracture place from tension side to compression side. Depending on the treatment type, the WA and TS values of the LVLs improved between 23% to 68% and 19.5% to 78%, respectively.
Fifteen structural composite lumber (SCL) products including laminated-veneer lumber (LVL), laminated strand lumber (LSL), oriented strand lumber (OSL), and parallel strand lumber (PSL) provided by Boise Cascade, LP, West Fraser, and Weyerhaeuser were tested for moisture-related properties in this study, also covering four reference materials: 16-mm Oriented Strand Board (OSB), 19-mm Canadian Softwood Plywood (plywood), 38-mm Douglas-fir and lodgepole pine solid wood. Water absorption, vabour permeance, vapour sorption, and dimensional stability were measured with limited replication by following relevant standards for a purpose of assisting in improving building design and construction, such as hygrothermal modelling of building envelope assemblies, design for vertical differential movement, and on-site moisture management.